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Home My WebLink AboutSWMU 69_Plan_20080101FINAL Submitted To: U.S. ARMY ENVIRONMENTAL COMMAND Submitted By. PARSONS January 2008 RECERIED JUN 1.1 2N DENS - 7FAYFFN, L i-� H EGIONAL nrM rF FINAL CORRECTIVE MEASURES IMPLEMENTATION PLAN FOR SWMU 69 JEEP DISMANTLING AREA FORT BRAGG, NORTH CAROLINA January 2008 Prepared for: UNITED STATES ARMY ENVIRONMENTAL COMMAND and FORT BRAGG DIRECTORATE OF PUBLIC WORKS Ross Miller PhD, PE Project Manager Daniel Griffiths, C.P.G. Technical Director �� %010610,,, RECEIVED / DENR / DWQ � � '�,.Of' H CA/RO'•., AQU1F:Pp-pRnTF Angie M. Cook, P.G. ` ,=��ti��E�S�6'��y'�'� MAR 0 �' �n"' .sECT�oN North Carolina Professional a SEAL � zoos Geologist No. 2110 2110 A. RECOVE® JUN 11200$ DENR - FAYE7TEVILLE REGIONAL OFRCE TABLE OF CONTENTS Page LIST OF ACRONYMS AND ABBREVIATIONS.......................................................... iv SECTION 1 - INTRODUCTION.................................................................................... 1-1 1.0 Introduction.......................................................................................................... 1-1 1.1 Corrective Action Objectives............................................................................... 1-1 1.2 Document Organization....................................................................................... 1-2 1.3 Facility Background............................................................................................. 1-2 1.4 Site History.......................................................................................................... 1-3 1.5 Geology and Hydrogeology................................................................................. 1-3 1.5.1 Site Geology............................................................................................. 1-3 1.5.2 Groundwater Hydrology.......................................................................... 1-4 1.5.3 Surface Water Hydrology........................................................................1-7 1.6 Summary of Previous Site Investigations ........................................ 1.6.1 USGS RFI 1994-1999..............................................................................1-7 1.6.2 Supplemental RFI (USACE) 2001-2002................................................ : 1-9 1.6.3 Surface and Subsurface Soil....................................................................1-9 1.6.4 Groundwater.......................................................................................... 1-10 1.6.5 2004 Sampling Event...........................................................................1-14 1.6.6 2007 Groundwater Sampling Event ............................. !.......................... 1-14 1.6.7 Surface Water and Sediment..................................................................1-21 1.7 Human Health Risk Assessment........................................................................ 1-21 1.7.1 Uncertainties.......................................................................................... 1-22 SECTION 2 - PROJECT ORGANIZATION, ROLES, AND RESPONSIBILITIES .................................... 2-1 2.1 Project Organization............................................................................................ 2-1 2.2 Responsibilities and Authorities.......................................................................... 2-1 2.2.1 Project Manager.......................................................................................2-1 2.2.2 Technical Director................................................................................... 2-2 2.2.3 Site Manager............................................................................................2-2 2.2.4 Site Health and Safety Officer................................................................. 2-2 2.3 Site Safety............................................................................................................ 2-2 SECTION 3 - CORRECTIVE MEASURES IMPLEMENTATION .............................. 3-1 3.1 Remedial Design Approach................................................................................. 3-1 3.2 Permitting and Regulatory Compliance............................................................... 3-2 3.2.1 Hazardous and Solid Waste Amendment Permit (RCRA permit)........... 3-2 3.2.2 Underground Injection Permitting........................................................... 3-2 3.2.3 Notifications.............................................................................................3-2 3.2.4 Storm Water Pollution Prevention........................................................... 3-2 3.2.5 Spill Prevention, Control, and Countermeasures.....................................3-2 -i- S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc 3.3 Remedial Construction Activities 3.3.1 Mobilization.............................................................................................3-3 3.3.2 Monitoring Well Installation....................................................................3-3 3.3.3 Organic Substrate Injection...................................................................... 3-4 3.3.3.2 Substrate Direct Injection Points ............................................. 3-8 3.3.3.3 Substrates................................................................................ 3-8 3.3.3.3 Substrate Preparation and Emplacement ............................... 3-10 3.3.4 Site Restoration...................................................................................... 3-18 3.3.5 Final Site Survey....................................................................................3-18 3.4 Performance Monitoring.................................................................................... 3-18 3.4.1 Groundwater Monitoring Well Network, Frequency, and Parameters.. 3-18 3.4.2 Surface Water Monitoring Locations, Frequency and Parameters........ 3-19 3.4.3 Performance Evaluations....................................................................... 3-22 3.4.4 Performance Monitoring Program Optimization ................................... 3-23 3.5 Contingency Planning........................................................................................ 3-23 3.5.1 Bioaugmentation Solution Preparation and Injection............................3-24 3.5.2 Contingency Substrate Injection............................................................3-25 3.6 Institutional Controls......................................................................................... 3-25 SECTION 4 - REPORTING AND DOCUMENTATION..............................................4-1 4.1 Corrective Measures Implementation Report ......................................................4-1 4.2 Performance Effectiveness Reports..................................................................... 4-1 4.3 Periodic Remedy Reviews.................................................................................... 4-2 SECTION5 - REFERENCES......................................................................................... 5-1 LIST OF TABLES No Title 1.1 Summary of Selected VOCs in Groundwater at SWMU 69 .............................. 1-11 1.2 Summary of Surface Water Data and Associated Regulatory Criteria..............1-25 1.3 Summary of Carcinogenic and Non -Carcinogenic Risks for all Receptors for the Groundwater Pathway............................................................................ 1-26 3.1 Injection Protocol Summary ................................................................................ 3-7 3.2 2-Month Substrate Distribution Sampling Event ............................................... 3-20 3.3 Year One Effectiveness Monitoring Program .................................................... 3-21 -ii- SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc TABLE OF CONTENTS (Continued) LIST OF FIGURES No. Title 1.1 Groundwater Potentiometric Surface Map .......................................................... 1-5 1.2 PCE and TCE Concentrations Detected in Groundwater . ................................. 1-15 1.3 TCE Concentration Contours in Middendorf Formation, 2001......................... 1-17 1.4 TCE Concentrations Detected in Groundwater, February, 2007....................... 1-19 1.5 Summary of Surface Water Analytical Results 1998-2006 ............................... 1-23 3.1 Proposed Substrate Injection Areas..................................................................... 3-5 3.2 Substrate Injection Areas 1 and 2..........................:........................................... 3-11 3.3 Substrate Injection Areas 3, 4, and 5................................................................. 3-13 3.4 Substrate Blending and Mixing System............................................................. 3-17 3.5 Substrate Injection System.................................................................................3-18 LIST OF APPENDICES Appendix Title A Substrate Loading Calculations B Under Ground Injection Permit Application 7 -iii- SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doe LIST OF ACRONYMS 1,1,2,2-TeCA 1,1,2,2-tetrachloroethane µg/kg micrograms per kilogram µg/L micrograms per liter , AEC Army Environmental Command AOC Areas of Concern bgs below ground surface BMP base master plan CFR Code of Federal Regulations cis-1,2-DCE cis-1,2-dichloroethene CMIR Corrective Measures Implementation Report COC chemical of concern COPC chemical of potential concern COR contracting officers representative CSM conceptual site model DERP Defense Environmental Restoration Program DNAPL dense nonaqueous-phase liquid DoD Department of Defense DPW Directorate of Public Works ELCR excess lifetime cancer risk EPC exposure point concentrations ft/day feet per day ft/ft foot per foot ft/yr feet per year' gprn gallons per minute GPS global positioning system HDPE high -density polyethylene HI hazard index HSWA Hazardous and Solid Waste Amendment ID inside diameter ILCR incremental life time cancer risk IRP Installation Restoration Program LTM long-term monitoring LUC land use controls MCL Maximum Contaminant Levels mg/L milligrams per liter MSL mean sea level MTBE methyl-tert butyl ether NCDENR North Carolina Department of Environmental Health and Natural Resources OD outside diameter OSHA Occupation Safety and Heath Administration OSWER Office of Solid Waste and Emergency Response Parsons Parsons Infrastructure & Technology PCB polychlorinated biphenyls -iv- S:\ES\Remed\745446 Fort Bragg PBC\20010 SWM1J-69\CM1P\ftna1\Fina1 Fort Bragg SW W69 CMIP.doc � PCE tetrachloroethene POC point of contact PRG preliminary remediation goal psi pounds per square inch PVC polyvinyl chloride QA/QC quality assurance / quality control RBC Risk Based Concentrations RCRA Resource Conservation and Recovery Act RFA RCRA Facility Assessment RFI RCRA Facility Investigation RME reasonable maximum exposure SAP/QAPP Sampling and Analysis Plan/Quality Assurance Project Plan SHARP Safety, Health, and Risk Program SPCC Spill Prevention, Control, and Countermeasure SVOC semi -volatile organic compound SWMU Solid Waste Management Unit TCE trichloroethene TEAP terminal electron accepting processes TO Task Order USAEC United States Army Environmental Command USEPA United States Environmental Protection Agency USGS United States Geological Society VOC volatile organic compound -v- SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc This page intentionally left blank SECTION 1 INTRODUCTION 1.0 INTRODUCTION Parsons Infrastructure and Technology Group, Inc. (hereafter referred to as Parsons) prepared this document for the United States Army Environmental Command (USAEC) and the Fort Bragg Directorate of Public Works (DPW) under contract number W91ZLK- 05-D-0016, task order 0001. This report presents the Corrective Measures Implementation Plan for Solid Waste Management Unit (SWMU) 69 in adherence to the Office of Solid Waste and Emergency Response (OSWER) Directive 9902.3- 2A dated May 1994 "[Resource Conservation and Recovery Act] RCRA Corrective Action Plan". The purpose of this document is to present the implementation plan for remedial actions at SWMU 69. 1.1 CORRECTIVE ACTION OBJECTIVES Corrective Action Objectives have been developed for SWMU 69 based on the site related contaminants, physical conditions, identification of applicable �r..egulations, and the baseline risk assessment. These objectives are to: • Prevent current human exposure to the chemicals of concern (COCs) in the groundwater through the ingestion, inhalation and dermal pathways. Currently the groundwater pathway is incomplete as there are no drinking water wells within or around SWMU 69, indicating that the potential risk to future residential receptors is low and within accepted levels. • Prevent future human exposure to unacceptable levels of COCs in the groundwater through the ingestion, inhalation and dermal pathways. • Reduce the levels of COCs in groundwater, in conjunction with monitored natural attenuation, to meet the North Carolina 2L standards (North Carolina Department of Environmental and Natural Resources [NCDENR], 2002). The selected corrective action will consist of enhanced bioremediation and natural attenuation. The application of enhanced bioremediation and natural attenuation is expected to reduce contaminant concentrations in groundwater and achieve the best overall results with respect to such factors as effectiveness, implementability and cost. SAES\Remed\745446 Fort Bragg PB020010 SWMU-69\CMIP\final\Final Fort Bragg SWMU69 CMIP.doc 1.2 DOCUMENT ORGANIZATION The report is divided into 5 sections and 3 appendices. Section 1 presents the introduction, summarizes the Corrective Action Objectives, provides the purpose and organization of this report, and provides background information on regulatory issues and previous investigations/actions conducted at the site. Section 1 also covers the environmental (physical) setting at the site and Fort Bragg in general and summarizes the results of a risk assessment previously conducted at SWMU 69. • Section 2 describes project organization, responsible and authoritative parties, and site safety. • Section 3 describes the scope of the final design, including the remedial design approach, related construction activities, and performance monitoring. • Section 4 describes project reporting and documentation requirements. • Section 5 provides references used in the preparation of this document. • Appendix A presents detailed substrate loading and radius of influence calculations completed to support the design of this application. • Appendix B contains a copy of the under ground injection permit application. 1.3 FACILITY BACKGROUND In 1988, NCDENR, in conjunction with the United States Environmental Protection Agency (USEPA) Region 4, issued a Hazardous Waste Facility Permit to Fort Bragg. The Former Jeep Dismantling Area was identified in the permit as SWMU 69 and was listed as requiring a RCRA Facility Investigation (RFI) based on the findings of the 1988 Fort Bragg RCRA Facility Assessment (RFA) conducted by Kearney, Inc and DPRA, INC (Kearney and DPRA, 1988) in accordance with RCRA. The United States Geological Survey (USGS) conducted an RFI of SWMU 69 from 1994 to 1998. The results of the RFI were presented in the April 1999 USGS report (USGS, 1999). Operable Unit 4 is a designation of the Installation Restoration Program (IRP) and consists of SWMU 69, SWMU 63, and Areas of Concern (AOC) E, F, and G. The RFI concluded that various volatile organic compounds (VOCs) identified during that investigation have migrated through the soils into the groundwater within and around the area of SWMU 69. Based on the results of the RFI investigation, NCDENR and Fort Bragg DPW determined that a supplemental RFI was warranted. Work supporting the supplemental RFI was performed in 2001 and 2002. Results of the initial investigation revealed the presence of chlorinated solvents, pesticides, and petroleum related compounds in the soils and groundwater at SWMU 69. The Supplemental RFI delineated the Chemicals of Potential Concern (COPCs) in the 1-2 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CM1P\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc soils in the suspected source area and concluded that the soils did not contain significant levels of COPCs above the screening criteria and therefore do not pose a continuing source of contamination to the groundwater at SWMU 69. It also concluded that the areas of detected concentrations of VOCs in the groundwater were the result of either the co - mingled plumes of several small releases over a widespread area or of multiple small releases at SWMU 69 over a period of years. A supplemental sampling event was conducted in 2004 to delineate the concentrations of VOCs in the groundwater in the area downgradient of SWMU 69. Groundwater samples were collected from existing select monitoring wells as well as from additional downgradient temporary monitoring well locations. An additional groundwater sampling event was conducted in February 2007. During the 2007 sampling event monitoring wells where contaminant concentrations exceeded regulatory criteria historically were resampled. A total of 16 wells were sampled in Febraury 2007. 1.4 SITE HISTORY The SWMU 69 area has been used for military equipment and vehicle storage since the 1970s and continues to be used for this purpose. The SWMU 69 area was also used for the dismantlement of jeeps from 1988 to 1990. A visual site inspection conducted during the 1988 RFA indicated that oil had leaked from old motors onto the unprotected ground. Stacks of vehicle parts were observed scattered over the ground surface. 1.5 GEOLOGY AND HYDROGEOLOGY 1.5.1 Site Geology Soil types in the Fort Bragg cantonment area range from moderately well drained to excessively well drained soils in the highly dissected uplands and have brittle loamy or clayey subsoil. These soils are the weathered by-products of the unconsolidated sandy sediments of the Coastal Plain. Soils located in the upland areas are generally sandy, acidic, and low in organic matter and fertility. Soils in the lower elevations are heavier in texture, contain more organic and clay material, and are poorly drained and swampy when adjacent to natural waterways. Because the soils often have similar properties, the transition zones are not always apparent. Several soil types are present within the immediate vicinity of SWMU 69 ranging from loamy sand to sandy clay. The major geologic formations in the Fort Bragg area (from oldest to youngest) are the Carolina Slate Belt, the Cape Fear Formation, and the Middendorf Formation. The Carolina State Belt is composed of metavolcanic, metasedimentary, and igneous rocks of Precambrian to Cambrian age and is the basement unit at Fort Bragg. The top of the Carolina Slate Belt is about 60 feet above mean sea level (msl) near the western edge of Fort Bragg (approximately 230 feet below ground surface [bgs]). The Cape Fear and Middendorf Formations are of Late Cretaceous age and are part of the Atlantic Coastal Plain deposits. The deposits are sediments that were deposited on top of the basement rocks and generally become thicker and dip toward the southeast. The Cape Fear and Middendorf Formations are non -marine in origin and are generally considered representative of deltaic deposits. f 1-3 S:\ES\Remed\745446 Fort Bragg PBC\200I0 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc The Cape Fear Formation is continuous throughout Fort Bragg and consists of pale -to - medium gray clays and sandy clays with some sand units. The lower part of the Cape Fear contains beds of greenish -gray clays, some of which have red mottling. The Cape Fear Formation contains more clay, and the individual quartz -sand beds are generally thinner and finer -grained than in the Middendorf Formation. The top of the Cape Fear Formation is located at approximately 80 feet bgs in the area of SWMU 69 and consists of clay and sandy clay ranging in thickness from 10 to 15 feet. The Middendorf Formation overlies the Cape Fear Formation, and is exposed at the ground surface throughout Fort Bragg. The Middendorf is composed of tan, cross - bedded, medium and fine-grained micaceous quartz sand and clayey sand interbedded with clay or sandy -clay lenses of limited extent. The basal unit of the Middendorf Formation within Fort Bragg is described as a sand layer with rounded quartzite pebbles in a clay matrix. Layers of hematite -cemented sandstone occur locally throughout the Middendorf Formation as do thin layers of kaolin and kaolin -cemented sandstone. 1.5.2 Groundwater Hydrology The same three geologic formations that underlie Fort Bragg also form the three fresh- water aquifers in this area. The saprolite-basement rock aquifer is composed of the saprolite underlying the Cape Fear Formation and the fracture zones in the uppermost part of the metamorphic and crystalline Cambrian and Precambrian basement rock. This saprolite-basement aquifer is generally assumed to yield little water, and there are no water supply wells known to tap solely into this aquifer. The Cape Fear aquifer is composed primarily of clays interbedded with silt and silty sands in the Fort Bragg area. The uppermost portion (5 to 10 feet) of the Cape Fear Formation is a compact, thick clay unit that serves as an aquitard which restricts the vertical movement of groundwater between the overlying sediments and the silty -sand units of the Cape Fear Formation, creating confined aquifer conditions for the groundwater found in the Cape Fear units below. There are no potable water supply wells in the Fort Bragg cantonment area that tap into the Cape Fear Formation; however, east of Fort Bragg, the Cape Fear aquifer is used for both public and industrial water supply. The primary water -bearing aquifer in the Fort Bragg area is the Middendorf aquifer, which consists primarily of coarse -to -fine-grained silty or clayey sands with interbedded light -gray to tan clay. Groundwater in the Middendorf aquifer is commonly under unconfined conditions. In some areas of Fort Bragg, a laterally extensive clay layer is present that separates the Middendorf aquifer into two water -bearing zones. The groundwater in the Upper Middendorf remains unconfined, whereas the groundwater in the lower zone is under confined or semi -confined conditions. The sandy soils of Fort Bragg are highly permeable leached beds of the Upper Middendorf Formation that allow rapid infiltration of precipitation. Precipitation is the primary source of groundwater recharge for the Middendorf aquifer. In the area of SWMU 69, groundwater is located at 35 to 40 feet bgs. The direction of groundwater flow is to the north-northeast, following the general slope of the ground surface and the direction of a surface -water drainage (Figure 1.1). Horizontal hydraulic 1-4 � S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc P, T RE NO 200' 0 200' 400, LEGEND SCALE, IN. FEET. liiT4 ley-, 100 - NIT ORING- WELL WITH FIGURE 1.1 69M SWmU - 69 (252.) WATER"4.EVEL- ELEVATIONS IOMETRIC GROUNDWATER POTENT AREA -OF GROUND -WATER MONIT011 SURFACE MAP PIEZOUIETER-' Corrective Measures St - udy Fort Bragg, North Carolina. -VI P:, GROUND �ATER.CONTOUR LINES 1 PARSONr �Apriim6yi Denver, Colorado Sources USACE,2006. - ..— .. -1. --,:..- : I I - draW1744468WMU 69 Surfece Mepxde me 6108107 pg 3 1-5 finally left blank conductivities were determined from slug tests conducted during the RFI (USGS, 1999) at nine wells at SWMU 69. Hydraulic conductivities for the Upper Middendorf ranged from 0.9 to 13 feet per day (ft/day), while the Lower Middendorf ranged from 14 to 78 ft/day. Using an average horizontal conductivity of 20 ft/day, an average porosity of 30 percent, and horizontal hydraulic gradients of 0.002 to 0.028 feet per foot (ft/ft), the USGS (1999) calculated the average linear groundwater velocity to range from 0.16 to 2.24 ft/day (58 to 818 feet per year [ft/yr]). The hydraulic conductivities determined from wells completed in the Lower Middendorf formation were higher overall than those from wells completed in the Upper Middendorf formation. 1.5.3 Surface Water Hydrology An east -west trending ridge.divides Fort Bragg into two drainage sub -basins. Surface water in the northern subbasin drains into tributaries of the Little River, while the surface water in the southern subbasin drains into tributaries of Cross Creek and Rockfish Creek. Streambeds generally consist of unconsolidated materials; typically silts, sands, and clays. , Several impoundments are present at Fort Bragg and include Young Lake in the northern portion of the cantonment area, Lake McArthur.in the northwestern corner of the installation, Mackellar's Pond in the northeastern part of the installation, and Smith Lake in the southeastern section. There are no surface water bodies within the area defined as SWMU 69 other than drainage ditches constructed to drain parking areas. However, there are two drainages that originate immediately north and northeast:-of`SWMU 69 (Figure 1.1) that may be impacted by contaminants originating from SWMU 69. The streams are unnamed but have been termed collectively as the Young Lake Tributary in USGS (1999). The two streams merge immediately south of Butner road and flow north- northeast toward Young Lake, located approximately 1 mile down stream from SWMU 69. 1.6 SUMMARY OF PREVIOUS SITE INVESTIGATIONS 1.6.1 USGS RFI 1994-1999 Initial work performed in 1994-95 by the USGS as part of the RFI included surface geophysics, a soil -gas survey, completion of 28 soil borings, and the installation of 10 monitoring wells. Seven surface -water and six streambed sediment samples were collected for analysis during this initial investigation. Results from the initial sampling revealed the presence of chlorinated solvents, pesticides, and petroleum -related compounds in the soil and groundwater. The chlorinated solvents tetrachloroethene (PCE) and trichloroethene (TCE) were the predominant contaminants detected in both soil and groundwater samples. In 1997, screening samples of both soil and groundwater downgradient from SWMU 69 were collected and analyzed in order to determine the location for groundwater monitoring wells that were subsequently installed in order to further delineate groundwater 1-7 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CM1P\fina1\Final Fort Bragg SWMU69 CMIP.doe contaminants. A second soil -gas survey was conducted in the area defined by the initial survey as having the highest concentrations of TCE, as well as an adjacent area north of SWMU 69. In 1997, 18 additional monitoring wells were installed in order to collect groundwater samples for laboratory analysis. These wells were screened in both surficial aquifers (the Upper and Lower Middendorf Formation) as well as the deeper confined aquifer (the Cape Fear Formation). This brought the total number of monitoring wells installed at SWMU 69 to 28. The 1999 RFI identified seven VOCs as COPCs in the groundwater at SWMU 69. These were benzene, carbon tetrachloride, chloroform, 1,2-dichloroethane, 1,1,2,2- tetrachloroethane (1,1,2,2-TeCA), PCE, and TCE. Of these COPCs, the chlorinated organic compounds (carbon tetrachloride, chloroform, 1,2-dichloroethane, 1,1,2,2-TeCA, PCE, and TCE) were the most prevalent. The concentrations of PCE and TCE were the highest of all analytes detected. COPCs were identified in 1999 by comparing analytical results to the USEPA Region III Risk Based Concentrations (RBCs) for tap water (USEPA, 1998), the USEPA Maximum Contaminant Levels (MCLs) (USEPA, 1996), and the NC Groundwater Standards (NCDENR, 2002). Three semi -volatile organic compounds (SVOCs) (bis(2- ethylhexyl)phthalate, 4-chloro-3-methylphenol, and n-nitrosodi-n-propylamine), one pesticide (dieldrin), and five metals (aluminum, iron, lead, manganese, and vanadium) were also identified as COPCs in the groundwater. A total of 63 soils samples were collected by the USGS during their investigations and compared to the USEPA Region 3 RBCs. Three SVOCs (benzidine, benzo(a)pyrene, and benzo(g,h,i)perylene), one polychlorinated biphenyl (PCB) (Aroclor 1260), iron, and vanadium were identified as COPCs in the surface soils. No COPCs were identified in the subsurface soils. In 1998, surface -water and sediment samples were collected by the USGS from five locations along the Young Lake Tributary. 1,1,2,2-TeCA was detected in two surface - water samples collected from downstream surface water sampling locations. PCE and TCE were also detected at low estimated levels in the same two samples. Chloromethane and 1,1,2,2-TeCA were determined to be COPCs in the surface water in the two unnamed tributaries to Young Lake. The PCE and TCE detections were below the screening criteria used at that time (USEPA Region III RBCs and the 1996 NCDENR Water Quality Standards Applicable to Surface Waters of North Carolina). TCE was detected in one of the sediment samples from the streambeds (below the screening criteria). The USGS concluded that the following COPCs identified in the groundwater: benzidine, ben_ zo(a)pyrene, benzo(g,h,i)perylene, dieldrin, and Aroclor 1260, were not considered to be environmentally significant because of their limited distribution, low concentrations, and infrequent detections above the screening criteria. They also concluded that the chlorinated organic compounds had migrated to the north-northeast within the Middendorf aquifer to a discharge area at the tributary to Young Lake and to the underlying Cape Fear aquifer. The USGS Report recommended further definition of the chlorinated solvent contamination in the soil and groundwater. r ` 1-8 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CM1P\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc 1.6.2 Supplemental RFI (USACE) 2001-2002 The first phase of work for the Supplemental RFI consisted of collecting soil samples from within the suspected source area as well as groundwater samples from the 28 existing groundwater wells. The second phase of this Supplemental RFI also collected a series of groundwater grab samples from numerous locations based on the conceptual site model (CSM) in order to further delineate the groundwater contamination. The data collected during this supplemental work is presented in the Site Conceptual Model Report for the Supplemental RHInvestigations of SWMU 69, Fort Bragg, NC (USACE, 2003). 1.6.3 Surface and Subsurface Soil Twenty-four soil borings were completed throughout the suspected source area. A total of 24 surface soil and 54 subsurface soil samples were collected for laboratory analysis from the borings based on field screening data and observations collected during drilling. The soil samples were analyzed for VOCs, SVOCs, PCBs, and chlorinated pesticides, based on results from the previous investigations. Results of the soil analyses were compared to the USEPA Region 9 Preliminary Remediation Goals (PRGs) for residential soils and to the North Carolina Soil to Groundwater concentrations (NCDENR, 2002). Five pesticide compounds (dieldrin, aldrin, methyoxychlor, 4'4-DDE and 4'4-DDT) and five SVOC compounds (benzo(a)anthracene, chrysene, fluoranthene, phenanthrene, and pyrene) were detected in some samples. Aroclor-1260 was the only PCB detected in ' 1 the soils. Seventeen VOCs were detected at least once in the 78 samples: 1,2,3- __ ' trichlorobenzene, 1,2,4-trichloroebenzene, 1,2,4-trimethylbenzene; 1,3,5- trimethylbenzene, 1,3-dichloropeopane, 1,4-dichlorobenzene, 2-buf h e, acetone, chloroform, chloromethane, methyl-tert-butyl-ether (MTBE), naphthalene, styrene, tetrachloroethene, trichloroethene, toluene, and total xylenes. TCE, PCE and toluene were detected most frequently. None of the analytes detected in either the surface or subsurface soil samples exceeded the USEPA Region 9 PRG screening values. Two compounds, dieldrin and TCE, had detections that exceeded NC Soil to Groundwater limits. TCE exceeded the NC soil to groundwater value (18.3 micrograms per kilogram [jig/kg]) in 8 of the 54 subsurface samples and dieldrin exceeded this value (1.13 µg/kg) in 10 subsurface soil samples. Seven of these dieldrin detections are thought to be the result of laboratory contamination, as dieldrin was also detected in the laboratory method blank at 1.3 µg/kg. Detections of TCE above the NC soil screening level ranged from 19 to 110 µg/kg. The depth of the groundwater in this area of SWMU 69 averages 38.5 feet bgs. Only two of the detections of dieldrin and TCE that exceeded the soil to groundwater criteria were from depths greater than 25 feet bgs, the remaining detections were all from depths between 4 to 25 feet bgs, with concentrations declining with depth' in the samples collected below 25 feet bgs. There was no correlation between any elevated PID response and the concentrations of the VOCs detected in the soil samples. Nor did any concentrations of TCE appear to correlate directly with the amount of clay in any soil samples, although the two highest y _ 1-9 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc � 1 concentrations of TCE were from samples that contained stiff gray clay, a surface sample and a sample from 35 to 36 feet bgs. There were no COPCs identified in the subsurface soils during the initial RFI and the excess lifetime cancer risk (ELCR) calculated for human receptors to the surface soils were within range of acceptable risk levels. Based on the infrequent detection of COPCs in the soils during the Supplemental RFI and the low levels detected, it was concluded by the USACE that the soils at SWMU 69 do not to pose a risk to human receptors. Therefore, it was concluded that no soil corrective action was necessary (USACE, 2006). 1.6.4 Groundwater The second phase of the Supplemental RFI consisted of installing piezometers to obtain more detailed information about the groundwater elevations across the area. Groundwater grab samples were also collected using direct push technology. Following the EPA Triad methodology, samples were analyzed in the field in order to provide real- time data. This phase of the Supplemental RFI was conducted in order to determine if the areas of higher concentrations were indicative of past source areas or if they represented zones of residual dense non -aqueous phase liquid (DNAPL). A total of 22 piezometers were installed around the area of the two small streams and the area south of Butner Road in order to obtain more detailed information concerning the direction of groundwater flow in this area and to construct a more realistic potentiometric surface map. Initial groundwater samples for field analysis were collected from the 22 piezometer locations. A direct-sparging ion -trap mass spectrometer was used to analyze groundwater samples using EPA Method SW8265. A total of 81 primary samples were collected and analyzed for TCE, PCE, and cis-1,2-dichloroethene (cis-1,2-DCE), based on the results of the previous investigations (Table 1.1). Figure 1.2 presents groundwater analytical data collected from site monitoring wells and grab samples collected using direct push drilling methods. Figure 1.3 depicts the interpreted extent of the SWMU 69 VOC plume based on the direct push grab sampling and groundwater monitoring well sampling conducted in 2001. The interpreted plume extent depicted in Figure 1.3 encompasses a total area of approximately 36 acres, as defined by the 1 microgram per liter (µg/L) TCE contour. In addition , a total of 5 CAH hot spots were defined based on data collected in 2001 (Figure 1.3). Results from this event provided a more detailed vertical and horizontal delineation of the PCE/TCE in the groundwater and support the conclusion that the chlorinated solvent contamination detected in the groundwater could be from two or more separate releases. Widespread minor concentrations are most likely remnants of previous small releases. In this case, dispersion and dilution processes were the major contributors to COC concentration reductions because of the subsurface conditions. Areas of significantly higher concentrations detected during this event coincided with those previously reported. Dissolved levels of PCE/TCE detected in the groundwater do not approach concentrations that would indicate the presence of dense non -aqueous phase liquids (Cohen and Mercier, 1993). 1-10 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc TABLE 1.1 SUIIVIN1ARY OF SELECTED VOCS IN GROUNDWATER SWMU69 FORT BRAGG, NORTH CAROLINA Screen Interval (ft below ground PCE d TCE y cis-1 2-DCE 1,1.2,2-TeCA y Well Location surface) Sampling Round ( ) m (t ( ) ( r North Carolina 2L Default Numerical Value" e' 0.7 2.8 70 0.17 North Carolina Surface Water Standard 3.3 30 4,900 4.0 69MWI 36.0-46.0 April-95 21.1' 25J NAB NA August-98 3.2 5.2 NA NA October-00 2.6 6.8 NA NA August-01 21 42 NA NA September-02 15 13 NA NA Febru -07 8.05 2.37 <0.29 <0.48 69MW2 36.0 - 46.0 April-95 ND `' ND NA NA August-98 0.I4J 0.33J NA NA October-00 ND ND NA NA August-01 ND 1.8 NA NA September-02 ND 1.4 NA NA Febru -07 <0.15 <0.70 <0.29 <0.48 69MW3 36.0-46.0 April-95 ND ND NA NA August-98 0.32.1 0.22J NA NA October-00 ND ND NA NA August-01 ND ND NA NA Se tember-02 ND ND NA NA 69MW4 1.5 - 6.5 October-00 ND ND NA NA August-01 ND ND NA NA Se tember-02 ND ND NA NA 69MW5 32.5-42.5 April-95 ND 6.2 NA NA August-98 0.98J 0.25.1 NA NA October-00 ND ND NA NA August-01 ND ND NA NA' Se tember-02 ND 2.3 NA NA 69MW6 31.0-41.0 April-95 ND 89 ND NA August-98 0.12J 26 ND NA October-00 0.5 51 2.2 NA August-01 0.591 75 2.1 NA September-02 ND 91 2.6 NA Febru -07 <0.15 15.4 0.68.1 <0.12 69MW7 32.0 - 42.0 April-95 ND ND NA NA August-98 0.43J 0.801 NA NA October-00 ND ND NA NA August-01 0.39J 4.0 NA NA Se tember-02 ND 2.0 NA NA 69MW8 205.0 - 225.0 August-98 <21 0.14J NA NA October-00 ND ND NA NA August-01 ND ND NA NA Se tember-02 ND ND NA NA 69MW9 40.4 - 50.4 April-95 ND 24 NA NA August-98 2.3 0.74J NA NA October-00 2.3 0.50 NA NA August-01 6.7 0.84J NA NA September-02� 13 1.2 NA NA Febru -07 5.23 0.991 <0.29 <0.48 69MW 10 35.0 - 45.0 April-95 ND 19 NA NA August-98 26 23 NA NA October-00 26 36 NA NA August-01 25 18 NA NA September-02 32 5.9 NA NA June-04 9.0 11 NA NA Febru -07 9.97 22.5 <0.29 <0.12 69MWI 1 13.0 - 23.0 August-98 0.541 0.14J NA NA October-00 ND ND NA NA August-0I ND ND NA NA September-02 ND ND NA NA June-04 ND ND NA NA S:\ES1RemedV45416FortBraggPB000010SWMIJ-69\CMIPTinaffable1.l.ds 1-11 TABLE 1.1 (Continued) SUMMARY OF SELECTED VOCS IN GROUNDWATER SWMU69 FORT BRAGG, NORTH CAROLINA Screen Interval (ft below ground PCE m TCE' cis-1,2-DCE m 1, I,2.2-TeCA ° Well Location surface) Sampling Round ( ) ( ( ( ' 69MW 12 12.5 - 22.5 August-98 0.34J 42J ND NA October-00 ND 28.3 ND NA August-01 0.321 30 0.74 NA September-02 0.421 28 ND NA June-04 ND 28 1.1 NA Febru -07 0.65 45.8 1.191 <0.12 69MW 13 15.0 - 20.0 August-98 0.21J 1.1 NA NA October-00 ND ND NA NA August-01 ND ND NA NA September-02 ND 0.461 NA NA June-04 ND ND NA NA 69MW 14S 35.0 - 45.0 August-98 0.27J 5.1 NA NA October-00 ND 3.9 NA NA August-01 ND 7.5 NA NA September-02 ND ND NA 0.40 Febru -07 <0.15 1.72.1 <0.29 <0.12 69MW 14D 72.0 - 82.0 August-98 0.30J ND NA 1.0 October-00 ND ND NA ND August-01 ND ND NA 0.42.1 September-02 ND ND NA ND Febm -07 0.251 1.731 <0.29 <0.12 69MW 15S 16.0 - 26.0 August-98 ND ND NA NA October-00 ND ND NA NA August-01 ND ND NA NA Se tember-02 ND ND NA NA 69MW 15D 34.0 - 44.0 August-98 0.24J 0.41J NA NA October-00 ND ND NA NA August-01 0.37.1 0.48J NA NA Se tember-02 ND 0.361 NA NA 69MW 16S 21.0 - 31.0 August-98 0.451 7.3 ND NA October-00 ND 7.8 ND NA August-01 0.37.1 20 0.61.1 NA September-02 ND 19 0.71J NA June-04 ND 23 0.95 NA Febru -07 <0.15 23.1 0.99.1 <0.12 69MW 16D 44.0 - 54.0 August-98 ND ND NA NA October-00 ND 0.19J NA NA August-0I ND ND NA NA September-02 ND ND NA NA June-04 ND ND NA NA 69MW 17S 19.0 - 29.0 August-98 24 9.11 NA NA October-00 15.5 3.2 NA NA August-01 25 4.8 NA 2.2 September-02 21 4.4 NA 0.651 Februa -07 13.8 3.62 <0.29 <0.12 69MW 17D 39.0 - 49.0 August-98 0.32J 7.8 NA NA October-00 ND ND NA NA August-01 1.6 2.1 NA 2.2 September-02 1.2 0.51J NA 0.65.1 Febru -07 1.48 1.211 <0.29 1.07 69MW 18D 25.0 - 35.0 August-98 0.30J 49 ND ND October-00 ND 45.7 ND ND August-01 0.371 49 1.2 0.38J September-02 0.401 38 1.3 0.51J June-04 0.43J 38 1.3 0.68J Febru -07 0.64 53.7 1.421 <0.12 69MW 19D 20.0 - 30.0 August-98 0.753 18 11 NA October-00 2.5 30.5 ND NA August-01 2.9 33 2.7 NA September-02 4.1 31 1.8 0.49J June-04 2.4 28 0.43J 1.9 Febru -07 5.06 26.2 <0.29 <0.12 SAESUtemedV45446 Fart Bragg PBC00010 SWMU-MCMIPUinaffable 1.I.As 1-12 TABLE 1.1 (Continued) SUMMARY OF SELECTED VOCS IN GROUNDWATER SW MU69 FORT BRAGG, NORTH CAROLINA Screen Interval (ft below ground al PCE TCE m cis- 1,2-DCE" 1,1,2,2-TeCA y Well Location surface) Sampling Round ( ) N ( ) ( ) ( ) 69NIW20D 32.0-42.0 Augltst-98 0.183 0.181 NA ND October-00 ND ND NA ND August-01 0.47J ND NA ND September-02 ND ND NA 0.751 June-04 ND ND NA ND 69MW21C 145.0- 165.0 August-98 0.47J ND NA NA October-00 ND ND NA NA August-01 ND ND NA NA Se tember-02 ND ND NA NA 69MW21D 30.0-40.0 August-98 0.35J 70 NA NA October-00 ND 26.9 NA NA August-01 0.36 51 NA NA September-02 0.423 20 NA NA June-04 ND 30 1.2 ND Febru -07 0.341 45 1.37J <0.12 69MW22C 184.0-194.0 August-98 0.35J 21 NA NA October-00 ND ND NA NA August-01 ND 4.3 NA NA September-02 ND II NA NA Febru -07 <0.15 4.64 <0.29 <0.12 69MW221) 66,0 - 76.0 August-98 0.151 1.5 NA NA October-00 ND 3.1 NA NA August-0I 0.30J 3.4 NA NA September-02 ND 3.9 NA NA June-04 ND 1.7 NA 6.2 Febru -07 <0.15 1.59J. <0.29 3.31 69TMW23 24.0 - 28.0 June-04 NA NA NA NA 69TMW24 24.0-28.0 June-04 NA 18 NA NA 69TMW25 28.0 - 30.0 bt June-04 NA 14 0.82J.- NA at PCE = tetrachloroethene, TCE = tichloroethene, DCE = dichloroethene, and TeCA = tetrachloroethane bt pg/L = micrograms per liter. J The NC 2L standard contains methodologies to calculate cleanup criteria other than the default 2L values. The default 21-numerical values are included in this table for reference. v J-Flag indicates the detected concentration is greated than the method detection limit and less than the method reporting limit. The concentration is therefore estimated. d NA = not available. "<" indicates that the analyte was not detected at a concentration greater than the indicated method detection limit. €t ND = indicates that the analyte was not detected at a concentration greater than the method detection limit. In this case the method detection limit was not available. w The screen interval at 69TMW25 is estimated as the well log could not be located by USACE. SAESUtcmed1745446 Fort Bragg PBC00010 VAIU-MCMIPUinaffable I.I.:Is 1-13 1.6.5 2004 Sampling Event The Supplemental RFI recommended that an additional groundwater well be installed downgradient of 69MW21D toward Young Lake to define the downgradient extent of the VOCs in the groundwater. In 2004, a decision was made by Fort Bragg to obtain groundwater samples from downgradient locations and install downgradient wells using direct push methods. A very stiff clay layer was encountered during drilling and only grab samples could be obtained using the direct push equipment. Three groundwater grab samples were collected, two from the west side of the tributary for Young's Lake and one from the east side. Ten existing wells were also sampled at this time and three surface water samples were collected. Results of the groundwater grab sample collected from the most downgradient location on the west side of the stream were non -detect; however, TCE was detected on the east side of the stream. Results from the 2004 sampling event are presented on Table 1.1. Analytical results from the monitoring wells sampled were similar to previous sampling results. All lab data, field sampling data sheets, and the Quality Assurance/Quality Control (QA/QC) Report for this data are located in Appendix E of USACE, 2006. NCDENR has requested that a permanent well be installed in the downgradient area of SWMU 69 north of Butner Road. The purpose of this new well will be to act as a sentry well below the toe of the SWMU69 plume and will act as a sampling point to determine if the SWMU69 plume is migrating in the downgradient direction. The proposed location of this well (to be installed by conventional drilling methods) is presented in Section 3 as part of the proposed remedial action presentation. The proposed well location is based on the results of the downgradient grab samples and discussions with NCDENR. 1.6.6 2007 Groundwater Sampling Event A groundwater monitoring event was conducted in February 2007 to collect an up-to- date data set to support the SWMU 69 remedial design. Table 1.1 summarizes the VOC data collected during this sampling event as well as relevant historic data. The February 2007 TCE in groundwater data set is also depicted on Figure 1.4 along with an updated plume foot print based on the 1.0 µg/L contour. During the February 2007 sampling event PCE and TCE were detected at concentrations above the NC 2L standards at a total of 5 and 9 locations, respectively. The maximum PCE concentration of 13.8 µg/L was detected at 69MW17S while the maximum TCE concentration of 53.7 µg/L was detected at 69MW18D. 1,1,2,2-TeCA was also detected at 2 locations at concentrations that exceeded the NC 2L standard, with a maximum detected concentration of 3.31 µg/L (69MW22D). PCE and TCE concentrations at the majority of monitoring wells have been generally decreasing for at least the last 5 to 6 years, with the notable exceptions of monitoring wells 69MW 12, 69MW16S, 69MW-18D, and 69MW19D (Table 1.1). r` 1-14 ) S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc P-2 w I D 24 F 21 m ` susc�r\ 3 a 1 Vb, tpc.; Ta 6 I f ' ✓ 1 � o / � � 1 � �j �. � I \ •c: Stctfr xL'a C- b If) I S I R E APB LEGEND nrf; 200' 0 200' 400' MONIT_ORINd WELL. LOCATIONS SCALE IN FEET 6M V 1 WITH CDNCENTRA i IONS F -10'a PIEZOMETER LOCATIONS, FIGURE 1.2 GROUNDWATER GRAB SAMPLE PCE AND TCE ~:ocA-rloNs CONCENTRATIONS DETECTED IN GROUNDWATER I DEP'TN OF SAMPLE, Corrective Measures Study =�riiiE ' PCEfi GE CONCENTRATIONS t Fort Bragg, North. Carolina Source USACE; 2006,i IPAR SS' O MS Notnc. Qata Presenter! in fhls:figure was collecEetl to Jgne.2004 Denver, Colorado- draw17<5446 SWNU 69 Surface Map.cdr:ma 09/13/OB pg.4 } 1-15 i nally let blank�� LEGEND North ��. MONITORING WELL WITH (21/42)C�a�LE CONCENTRATIONS IN ems ` GEOPROBE GRAB SAMPLE 6.9� 69TW10 LOCATIONS -WITH PCE/TCE (ND/2,4) CONCENTRATIONS IN ug/L i A /l/ TCE ISOCONCENTRAT1 N —50 CONTOUR IN pg/L, (DASHED WHERE APPROXIMATE - T! u�oo z I I IfN ("` 112 (6.7/0 1. 6 as $ h Wnb . ..- 30J/ -344) 1 /\ Al 22C/N f 'RRI�CC(qy{yl 69MW3 axe w� (ND/.ND) Y S W) gg7t. exm 293x Q� t 10 OVA T--TND/ND) 69MWll (ND/ND) 200 0 200! 400 SCALE IN FEET FIGURE 1.3 SWM U-69 TCE CONCENTRATIONS CONTOURS IN MIDDENDORF FORMATION (pg/L) (AUG 2001) Corrective Measures Study h Fort Bragg,_North Carolina PARSONS Denver, 1- dravA7454 6 SU1'"U 69 Surface Map.cdr ma 5/08/07 pg 5 rally left blank VTTAMW4 13'- VrTAMW5 �VTTAMVro VT7AMW72�^ VTTAM WB AEHAV--2 VTTAMWt0` VrTAMW9 AEHAV-3 t VTTAMWtt c17 ; bum J 6f3MW22. 1.59J" 2.37, S (J 7 0 �69MW3 i"69MW -' *.69MW10. 112MW4 t Legend ® Groundwater, Monitoring Well and TICE "An asterisk indicates a temporary -well installEil 12MW3 ® Surface Water Sample Locations I -F-�— Rail Roads Stream 69TM W23 0 m TCE Concentration C®nfio.ui° l r . 1.0 ug/L l s — — — 1.0 ug/C inferred i SWMU-69 . _ Corrective Measures Study u 20" UgIL TCE CONCENTRATIONS !: 50 ug/L DETECTED IN GROUNDWATER FEBRUARY, 2007 0 . " 300 : 6.00 FT. BRAGG, NORTH CAROLINA " Feet j CHECKED BY D. Gritfitns 1 '_ 1 e� { {� lInChe. UGIIS3OO feel SONS DRAFTED BY C.ten9raak Co C9 k, FILE SVVMLL69 TCE_Feb2 DATE SM7 1-19 12MW9 FIGURE 1.4 orally left blank r � -- 1.6.7 Surface Water and Sediment Two unnamed intermittent streams (termed "unnamed Young Lake Tributaries" by the USGS) drain the hillside north of SWMU 69. Both streams empty their contents eventually. into Young Lake, located approximately I mile to the north-northeast. The surficial groundwater located in the uppgr and lower Middendorf Formation is the primary source of surface water in the streams. During heavy rain events the streams also collect surface water runoff from the SWMU 69 area as well as the area to the north of SWMU 69. A total of fifteen surface -water samples have been collected during the various investigative phases at SWMU 69. Figure 1.5 shows the locations _of each sample and presents a summary of the analytical results. Five samples were collected in 1998, four samples in 2001 (an additional sample was planned; however, the stream was dry in that location), and three samples in 2003. Three additional samples were collected in 2006. The analytical data for these samples is summarized in Table 1.2. Several of these samples have been collected from the same location over a period of eight years (Figure 1.5). Both surface -water and sediment samples collected in 2001 and 2003 were from the same locations,.as the samples collected by the USGS in order to confirm the previous detections. Table 1.2 summarizes the surface water detections and compares these results to the NCDENR screening criteria for protection of human health as described by North - Carolina Rule 15A NCAC 213, updated in 2004. 1,1,2,2-TeCA, PCE, TCE, and cis-1,2- DCE have all been detected sporadically in the surface water. However, none of these detections have exceeded the NCDENR screening criteria for the pratectioii of human health indicating that the surface water at SWMU 69 does not currently present a risk to human receptors. 1.7 HUMAN HEALTH RISK ASSESSMENT A human health risk assessment was performed by ABB, INC. in 1995 after the initial RCRA RFI was performed (USACE 2006). The incremental life time cancer risk (ILCR) for carcinogens and hazard index for non -carcinogens were calculated for exposure of future excavation workers to surface soils, and adult and child residents to surface soils, subsurface soils, and groundwater. There were no human health COPCs identified for subsurface soils. For the excavation worker, the ILCR associated with exposure to surface soils was 7 x 10-8 and had a hazard index (HI) of 0.01. Both the adult and child resident exposure to surface soils was 1 x 10-5. Hazard Indices were 0.16 and 0.6, respectively. Incremental levels of risk for workers were minimal and all levels are within the USEPA Region 4's levels of acceptable risk (1 x 10-5 to 1 x 10-4) and require no corrective action. This site currently has an industrial use, is covered in gravel and asphalt, and is behind a locked fence. Because this site has a non-residential use, there are no current risks to residential receptors. 1-21 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc Risks for residential receptors for the groundwater pathway were also calculated. The maor contributors to a cancer risk exceeding the ] 0- level were tetrachloroethene (3 x 10- ), trichloroethene (3 x 10-5), chloroform (2 x 10-5) and arsenic (5 x 10-4). Because arsenic is a naturally occurring element in the Middendorf Formation, ABB (1995) concluded that the risk attributable to arsenic was overestimated. Also, arsenic was only detected in 3 of the 28 groundwater samples and all arsenic levels detected were below the USEPA MCLs and NC 2L values. Risks for future receptors for the groundwater pathway were reevaluated using the more current 2002 sampling data. Currently, drinking water at Fort Bragg is from surface water sources. Therefore, the pathway is not complete for groundwater and no risk to current human receptors exists from SWMU 69 site groundwater. However, there is some potential for future groundwater contaminant plume discharge to the unnamed tributaries to Young Lake, which would pose a risk to surface water receptors. In addition, the state of North Carolina requires that groundwater be remediated to the NC Groundwater 2L standards, thus remediation is warranted on this site. Exposure point concentrations (EPC) were calculated by using the arithmetic average of the groundwater concentrations for each of the four COPCs following EPA Region 4 guidance (Table 1.3). These averages were calculated by using a value equal to '/2 the reporting limit for those samples that did not have a detection reported. Exposure point calculations are presented in Appendix B of the Final Corrective Measures Study document (Parsons, 2007a). Groundwater data from wells upgradient of SWMU 69 (69MW7, 69MW22D, 69MW20) were omitted as well as data from wells completed in the lower Cape Fear aquifer (69MW8, 69MW22C, 69MW21Q. The EPC is considered to be reasonable maximum exposure (RME) for future receptors to the groundwater. 1.7.1 Uncertainties Three major types of uncertainties should be considered when reviewing the results of the exposure assessment: 1. Uncertainties associated with predicting future land use, 2. Uncertainties associated with estimating constituent concentrations at receptor locations, and 3. Uncertainties associated with assumptions used in the exposure models. The uncertainties associated with the SWMU69 exposure assessment are presented in detail in the final SWMU 69 Corrective Measures Study (Parsons 2007a). 1-22- SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIPTna1\Fina1 Fort Bragg SWMU69 CMIP.doc AN NO AN NO BOW" 20 REWLTS rq Temwastow 3W am/ LEGEND 'iCALE IN FEET FIGURE 1.5 MONITORING WELL SUMMARY OF SURFACE WATER PIEZOMETER ANALYTICAL RESULTS 1998-2006 GRAB SAMPLE Corrective Measures Study Fort Bragg, North Carolina SURFACE WATER SAMPLE LOCATIONI§ PARSONS Source: USACE, 2006. Denver, Colorado onally left blank TABLE 1.2 SUMMARY OF SURFACE WATER DATA AND ASSOCIATED REGULATORY CRITERIA SWMU69 FORT BRAGG, NORTH CAROLINA Location: Sample No.: Sampling Date: NC Screening Standards SWMU-69 YLT2-SW2 12-Au -98 SWMU-69 YLT3-SWI 12-Au -98 SWMU-69 YLT4-SWI 12-Au -98 SWMU-69 YLT5-SWI 12-Au -98 SWMU-69 YLT6-SW1 12-Au -98 SWMU-69 69SW1 27-Au -01 SWMU-69 69SW2 27-Au -01 SWMU-69 69SW3 27-Au -01 SWMU-69 69SW4 27-Au -01 Current Surface Water Standard Surface Water Source VOCs 8260B 1,1 2,2-Tetrachloroethane L 4.0 NCHH 1.0 - U 1.4 - U - U 1.2 - U - U - U Chloromethane L 96 NCHH - U - U - U - U - U - U 0.4 - U 031 J cis-1,2-Dichloroethene /L 4,900 NCHH _U _U - U - U - U - U - U - U _U Toluene 11.0 NCAL -U -U -U -U -U -U 0.8 -U -U Tetrachloroethene /L 3.3 NCHH, _U - U 0.15 J - U - U - U - U - U - U Trichloroethene /L 30 NCHH 1.1 - U 1.3 - U - U 1.3 - U - U - U Location: Sample No.: Sampling Date: NC Screening Standards SWMU-69 69SW7 12-Au -98 SWMU-69 69SW8 12-Au -98 SWMU-69 69SW9 12-Au -98 SWMU-69 SW106 6-Mar-06 SWMU-69 SW206 6-Mar-06 SWMU-69 SW306 6-Mar-06 Surface Water Standard Surface Water Source VOCs 8260B 1,1,2 2-Tetrachloroethane L 4.0 NCHH - U - U - U - U - U 0.27 J Chloromethane L 96 NCHH - U. - U - U - U - U - U cis-1 2-Dichloroethene L 4,900 NCHH - U - U - U 0.23 J 0.24 J - U Toluene /L 11.0 NCAL - U - U --U - U . - U - U Tetrachloroethene L 3.3 NCHH - U - U - U - U - U - U Trichloroethene /L 30 NCHH - U - U - U 0.87 J 1 0.85 J 0.85 J DATA QUALIFIER CODES: J = Analyte positively identified; numerical value is approximate (below quantitation limit, but above method detection limit). U = Analyzed for, but not detected above quantitation limit. NS = Not Sampled. NOTES: NCAL = Surface Water Criteria based on North Carolina Aquatic Life Surface Water Standards, 213. NCHH = Surface Water Criteria based on North Carolina Human Health Water Standards, 213. NRWQC = EPA National Recommended Water Quality Standards. NL = Not listed. S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CM1P\fina1\Tab1e 1.2.a1s 1-25 Table 1.3 Summary of Carcinogenic and Non -Carcinogenic Risks for all Receptors for the Groundwater Pathway Fort Bragg, North Carolina Chemical of Concern Carcinogenic Non-Carcino enic Child Resident Adult Resident Installation Worker Child Resident Adult Resident Installation Worker Tetra chloroethene 1.21 x 10"5 3.96 x 10'5 1.09 x 10-1 0.023 0.001 -- Trichloroethene 1.74 x 10" 1.82 x 10-' 4.90 x 10 0.403 0.017 -- 1,1,2,2- Tetrachloroethane 4.63 x 10-' 1.71 x 10"6 4.12 x I e -- -- -- Chloroform 4.63 x 10-7 2.32 x 10"' -- 0.008 0.0004 0.01 Total 1.48 x le 4.07 x 10"5 1.62 x 10- 0.434 0.018 0.01 1-26 SAES\Remed\745446 Fort Bragg PBC\20010 SWMIJ-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc SECTION 2 PROJECT ORGANIZATION, ROLES, AND RESPONSIBILITIES 2.1 PROJECT ORGANIZATION This project is being conducted by Parsons Infrastructure and Technology Group (Parsons) under contract to the USAEC and in conjunction with the Fort Bragg DPW. The lead regulatory agency on, this site is the NCDENR. 2.2 RESPONSIBILITIES AND AUTHORITIES Parsons will.,serve as the Contractor for all remedial activities specified in this corrective measures implementation plan, and will be . responsible for planning, implementation, and documentation of engineering and remedial activities. Parsons will also be responsible for compliance with applicable QA/QC requirements, health and safety requirements, and regulatory requirements during the work. Parsons will report directly to USAEC, through the Army's Contracting Officer's Representative (COR), and may be supported during various activities by one or more subcontractors. Subcontractors will comply with all applicable Army and Parsons requirements. The fQlowng sections describe the responsibilities of key Parsons project personnel. 2.2.1 Project Manager The project Manager for this contract is Dr. Ross Miller, PE, PhD, CIH. Dr. Miller's responsibilities include: • The effective execution of the Task Order (TO)/project, • Serving as Army's and -regulator's primary point of contact (POC), • Assigning the necessary technical and support personnel to execute this project, • Cost, schedule, and quality conformance, • Preparing project status reports, • Preparing any contract modifications, and participating in contract negotiations, • Small business goal conformance, and • Project closeout. 2-1 SAES\Remed\745446 Fort Bragg PB020010 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc 2.2.2 Technical Director The technical director for this project is Mr. Dan Griffiths, CPG. Mr. Griffiths' responsibilities include: • Reviewing technical submittals for the project, Identifying technical expertise for project support, • Performing monthly audits of field activities. 2.2.3 Site Manager The site manager's responsibilities will include: • Coordination with Fort Bragg personnel for site access, utility clearances, and access to potable water from a nearby fire hydrant or approved surface water impoundments, • Ensuring that this CMIP is implemented completely and properly, • Ensuring that all site activities are conducted safely, • Personnel coordination, and • Performing and documenting site audits. 2.2.4 Site Health and Safety Officer The site health and safety officer's responsibilities will include: • Site specific health and safety training for all Parsons and subcontract employees, • Daily health and safety meetings, • Daily site health and safety inspections, • Periodic site health and safety audits, • Maintenance of site health and safety (as well as Occupation Safety and Health Administration [OSHA]) records, and • Coordination of Parsons corporate health and safety audits as necessary. 2.3 SITE SAFETY Parsons has implemented a Corporate Safety, Health, and Risk Program (SHARP) which requires Project Managers to implement effective programs in these areas. Parsons' goal is zero accidents and zero injuries with work tasks designed to minimize or eliminate hazards to personnel, equipment, and the general public. A SHARP compliant site specific health and safety plan has been developed for this project and is incorporated by reference (Parsons, 2007b) into this CMIP. 2-2 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc SECTION 3 CORRECTIVE MEASURES IMPLEMENTATION 3.1 'REMEDIAL DESIGN APPROACH The enhanced anaerobic bioremediation technology will be applied to five areas within the SWMU 69 TCE plume where TCE concentrations have historically been highest (Figure 3.1). The application of enhanced bioremediation in these "hot spot" areas is intended to reduce contaminant mass present in the subsurface and thereby reduce the time required for natural attenuation to reach NC 2L standards in groundwater within the SWMU 69 plume extent. The.mixed substrate for this application will consist of a soluble- substrate (sodium lactate) to provide an immediate mass of bioavailable organic carbon to drive geochemistry into anaerobic conditions, and food -grade vegetable oil to provide a slow release source of organic carbon to drive reductive dechlorination over the long term. This mixture typically supports anaerobic biodegradation for 4 to 6 years. A pH buffering product consisting of a proprietary mixture of naturally occurring %y } long lasting buffering agents, water, dispersants, and food grade preservatives will be added to maintain neutral pH conditions within each reaction area. Microbial populations capable of dechlorinating chlorinated solvents have been shown to `require near neutral pH conditions (pH greater than 6) to grow effectively (Volkering and Pijls, 2004), making pH buffering an important factor in successful enhanced bioremediation applications. The injection well network in each hot spot will consist of approximately 10 direct push injection points installed in overlapping arcs or lines. The spacing between the injection points. will be approximately 9 to 10 feet to ensure adequate substrate distribution. Half of the injection points will be completed as temporary small diameter wells to allow for future injections of amendments and additional organic substrate if necessary. During the initial injection approximately 1,500 gallons of organic substrate mixture and pH amendment will be injected at each point, flooding the area with organic carbon. After the first twelve months of performance monitoring, the geochemical data and progress of COC degradation in the hot spots will be reviewed. If degradation is lagging and conditions are sufficiently anaerobic, a supplemental volume of approximately 200 to 300 gallons of dilute bioaugmentation culture and a pH amendment may be injected into each of the small diameter wells. The bioaugmentation culture will consist of a non- pathogenic, naturally occurring population of microbial strains known to be capable of complete dechlorination of PCE, TCE, and 1,1,2,2-tetrachloroethane and its degradation products (cis-1,2-DCE and vinyl chloride). If it is applied the bioaugmentation culture will be provided by SIREM Laboratories, which has developed a bioaugmentation f _ rr 3-1 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CM1P\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc product called KB-1 that was specifically developed for the degradation of PCE and TCE. A second injection of organic substrate may be applied to the SMWU 69 hot spot areas in the event that the initial injection' does not provide adequate organic carbon to the subsurface. 3.2 PERMITTING AND REGULATORY COMPLIANCE 3.2.1 Hazardous and Solid Waste Amendment Permit (RCRA permit) A Hazardous and Solid Waste Amendment (HSWA) permit is currently in place at Fort Bragg.. The Fort Bragg HSWA permit was due for renewal in 2007 and the renewal application has been submitted to NCDENR for review. The permit renewal application briefly presents remedial activities planned at SWMU 69 as presented in more detail in this document. There will be a 30-day public comment period associated with the HSWA permit application. After the comment period is concluded the application will be finalized and the HSWA permit will be renewed. The new HSWA permit will include a description of the corrective actions at SWMU 69. 3.2.2 Underground Injection Permitting An underground injection permit is required for the injection activities at SWMU 69. The injection permit will be obtained from the NCDENR Aquifer Protection Section through a formal application and review process. The application for the underground injection permit for injection activities at SWMU 69 is attached as Appendix B. 3.2.3 Notifications Fort Bragg DPW, NCDENR, and USAEC will be kept abreast of field schedule developments through regularly scheduled bi-weekly conference calls. The NCDENR Aquifer Protection Section will not typically attend the biweekly project conference calls. Therefore the NCDENR Aquifer Protection Section Representative (Qu Qi) will be updated periodically by Parsons or by the project NCDENR representative (Marti Morgan). 3.2.4 Storm Water Pollution Prevention It is anticipated that the ground surface and related vegetation at SWMU 69 will be disturbed only minimally during injection activities at the five hot -spot areas because drilling activities will be limited to direct push drilling and vehicle traffic off currently established roads will be minimal. Thus, a storm water pollution prevention plan is not required for this effort. 3.2.5 Spill Prevention, Control, and Countermeasures Oils stored on -site (soy bean oil) are subject to regulation under 40 CFR 112, Oil Pollution Prevention. The total volume of vegetable oil stored on site will be greater than the 1,320 gallon limit specified in the Spill Prevention, Control, and Countermeasure (SPCC) regulations under 40 CFR 112 Subpart C. The emulsion product and pH buffer also planned for injection at SWMU 69 do not fall under this regulation as these products 3-2 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc = do not have similar physical properties as oil (e.g., solubility and density) and the volumes of these products stored on site will be relatively low (less than 1,320 gallons). A SPCC plan for both SWMU 69 and SWMU 103 will be developed and published under a separate cover. 3.3 REMEDIAL CONSTRUCTION ACTIVITIES 3.3.1 Mobilization Mobilization activities will commence upon acceptance of the final SWMU 69 CMIP and the receipt of all required permits and authorizations as discussed in Section 3.2. Mobilization activities will consist of the following tasks: • Coordination of utility clearances for all drilling locations. • Site access coordination with Fort Bragg. The intended drilling and injection areas are not located in high security or limited access areas. However, facility coordination will be necessary for proper sighting of equipment and materials. • Delivery of organic substrates and injection equipment. • Mobilization of one or two drilling contractors to support the monitoring well installation activities and the direct push injection activities. • Installation of silt fencing on the downhill side of each injection area as well as the substrate staging and injection area. 3.3.2 Monitoring Well Installation Two new monitoring wells (69MW23 and 69MW 161) will be installed to complete the groundwater monitoring network required to evaluate the performance of natural attenuation at SWMU 69. 69MW23 will be installed north of the intersection of Butner and Varsity Roads and 69MW13I will be installed in the immediate vicinity of existing wells 69MW16S and 69MW16D, as presented on Figure 3.1. 69MW23 will be installed such that the screen interval will be located at 25 to 35 feet bgs while 69MW16M will be installed such that the screen interval is located at approximately 31 to 41 feet bgs, between the screen intervals at 69MW16S and 69MWI6D. 69MW23 will be installed using hollow stem auger drilling methods and will be constructed of two inch inside diameter (ID) polyvinyl chloride (PVC) well materials. The 69MW23 boring will be advanced to the boring termination depth using 4-1/4 inch ID hollow stem augers. After the augers are advanced to depth the monitoring well will be installed inside the auger. After the monitoring well is installed the augers will be withdrawn, and filter sand (#10-20) will be emplaced within the annular space between the outside of the PVC screen and the inside of the borehole to a level approximately 2 feet above the top of the PVC screen. The remaining annular space will be sealed with approximately 2 feet of bentonite chips immediately above the sand filter pack and concrete/bentonite grout from the top of the bentonite chip seal to approximately 2 feet 3-3 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc below ground surface. The top of the casing will be finished with the installation of a water tight "J-plug" cap within a steel "stick-up" type surface completion set in a concrete collar. 69MW16I will be installed using direct push drilling methods and will be constructed of 0.75 or one inch ID PVC well materials. The screen materials used to install 69MW 16M will consist of "pre -packed" screens that have sand packs already installed around the screens prior to installation. The boring for 69MW16M will be advanced using 2.125 or 3.25-inch Geoprobe rods until the total depth of the boring (41 feet) is reached. After the total boring depth is reached the pre -packed screens and appropriate riser pipe will be installed inside the Geoprobe rod and the rod will be withdrawn to allow the natural aquifer matrix to collapse around the pre -packed screens and riser pipe. A concrete/bentonite slurry will be tremmied into the borehole from the top of natural collapse to ground surface to serve as a sanitary seal around the well casing. The new well will be completed by installing a stick-up type locking steel well completion over the PVC well casing. The well completion will be surrounded at groundsurface with a concrete collar to ensure that the completion remains stable. The installation of new permanent monitoring well 69MW23 will be conducted in accordance with North Carolina State regulations as specified in Subchapter 2C Section .0100 of the North Carolina Administrative Code. 69MW19I will not be installed in accordance with Subchapter 2C Section .0100 of the North Carolina Administrative Code in that a bentonite chip seal will not be installed about the pre -packed screen interval. 3.3.3 Organic Substrate Injection 3:3.3.1 Substrate Injection Wells A total of 62 injection locations will be installed in 5 injection areas (coinciding with 5 previously identified hot spots). 31 of the 62 injection locations will be installed as temporary small diameter PVC wells. The temporary PVC injection wells will consist of 0.75-inch or 1-inch ID PVC injection wells installed using a direct push rig. The approximate orientation of these points is shown on Figures 3.2 and 3.3. The injection points will be constructed with screen lengths of up to 15 feet and will be installed as specified in Table 3.1. The direct push drilling equipment will advance 2.125-inch outside diameter (OD) steel casing through the vadose zone and into the saturated zone. The steel outer casing will be outfitted with an expendable tip. After the steel direct push casing has been advanced to approximately 1-foot below the bottom of the screened interval the steel casing will be pulled back approximately 1-foot to dislodge the expendable steel point. After the expendable point has been dislodged the well will be installed inside the steel direct push casing. Each injection well will consist of 10 to 20 feet (depending on the treatment area) of 0.75-inch or 1-inch ID machine slotted Schedule 40 PVC screen flush threaded to the appropriate length of non -slotted riser pipe. The riser pipe will extend from the top of the screen interval to approximately 2-feet above ground surface. The entire well stick, consisting of PVC screen and casing will be installed inside the steel direct push casing and the steel casing will be withdrawn to allow the natural formation material to collapse 3-4 f S:\ES\Remed\745446 Fort Bragg PBC\200I0 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc VTTAMW4—43-VTTAMW5 VTTAM WS �7 VTTAMW12 -Q TTAMW31 ITTAMWI VTTAMW8 VTTAMW2AEHAV-2 VTTAMW70 IVTTAMW9 f69MW8 AEHAV--3 69MWI' .. i69MW5 `VTTAMWII CO ool 69MW2 69MW9 - SWMU 69 169MWi 12MW9 - 69M W22% Ed �' 69MWI 69MWI i 69MW22C� �P 71- ' Q J69MW3 �� 89MW4.1 12MW4 I. ov ji orally left blank TABLE 3.1 INJECTION PROTOCOL SUMMARY SWMU-69 FORT BRAGG, NORTH CAROLINA Injection Points Substrate Injection Mixture { Injection Injection Total Emulsion Product 50% oil b weight) Buffering Makeup Well Interval Spacing Points Volume Soybean Oil Lactate Neat So bean Oil Agent Water ID feet feet (gallons) (gallons) (pounds) (pounds) (gallons) ounds)(gallons) (pounds) ( allons) Injection Area-1 1 35-44 9 10 140 69 1 539 62 672 5,242 Injection Area-2 31-40 9 15 210 104 809 93 1,008 7,862 Injection Area-3 21-30 9 15 210 104 809 93 1,008 7,862 Injection Area-4 15-35 9 10 350 173 1348 154 1,505 11,739 Injection Area-5 31-40 9 12 . 168 83 647 74 890 6945 TOTALS: 62 1,078 533 4,152 476 5,083 39,650 NOTES: Sodium Lactate Product 1. Assumes WiIlClear sodium lactate product is 60 percent sodium lactate by weight 2. Molecular weight of sodium lactate (CH,-CHOH-COONa) = 112.06. 3. Molecular weight of lactic Acid (C6H(,Or) = 90.08. 4. Specific gravity of WiIlClear Product= 1.323 @ 20 degrees Celsius. 5. Weight of WillClear Product =11.0 pounds per gallon. 6. Pounds per gallon of lactic acid in product =1.323 x 8.33 lb/gal H2O x 0.60 x (90.08/112.06) = 5.31 lb/gal. NOTES: Vegetable Oil Emulsion Product 1. Assumes emulsion product is 50 percent soybean oil by weight. 2. Soybean oil is 7.8 pounds per gallon. 3. Assumes sepcific gravity of emulion product is 0.96 and that emulsion product is 4 percent sodium lactate by weigt 98 1,058 14, 147 1,588 21, 147 1,588 21, 245 2,646 35. 118 1,270 16, 755 8,150 107 Total Volume Injection Interval feeti(percent)feet Estimated Effective Porosity Radius of Influence Injection Time at 4 gpnr (days) ubstrate pounds)(gallons) Water+ Substrate 5,832 14,896 9 25% 5.4 8 8,911 22,365 9 25% 5.4 6 8,911 22,365 9 25% 5.4 6 13,091 37,065 19 25% 5.8 10 7,856 17,993 9 25% 5.3 5 44,601 114,684 Days: 35 Drums Gallons Total Tales Gallons Total Emulsion Product Emulsion Product 1 55 19.6 1 220 4.9 Neat Soybean Oil Neat Soybean Oil. 1 55 92.4 1 220 23.1 Buffering Agent IBuffering Agent I 55 13.6 1 1 250 3.0 SAES\Reme&745446 Fort Bragg PBC\?0010 SWMU-691CMIP\fina1\Tab1e 3.I.x1s 3-7 around the PVC injection well. The steel direct push casing will be entirely withdrawn from around the injection well and the depth to natural collapse will be measured using a steel tape attached to a sounding weight. In the event that natural soils do not collapse around the screen interval the annular space between the outside of the PVC casing and the wall of the borehole will be filled with new, clean 20-40 silica well sand. If the natural soils collapse to above the top of the screened interval than the remaining open annular space will be filled with sodium bentonite chips of granular bentonite as appropriate. Once each well is installed a threaded cap will be installed in the top of the well casing to seal the well. Each injection well will be completed with a temporary PVC surface casing to protect the injection well from potential damage. The temporary PVC surface casing will consist of a 5-foot section of 4" PVC schedule 40 pipe that will be installed around the injection well and buried in the ground to approximately 2-3 feet in depth. A bentonite surface sanitary seal will be installed at the bottom of the surface completion to keep surface water from infiltrating down the borehole. A threaded PVC cap will be installed at the top of the completion casing to seal the completion. 3.3.3.2 Substrate Direct Injection Points Substrate will be injected into the subsurface directly through temporarily installed steel GeoprobeTM rods and screen point sampling tools (SP 15 or SP 16 as appropriate) at one half of the injection locations (locations .that will not be completed as temporary injection wells). Substrate injection at these "direct injection" locations will be conducted in the same way as the injection wells except that the substrate will be injected into the subsurface directly through the GeoprobeTM rods instead of through PVC well Y casings. The GeoprobeTM rods and associated tool string will be removed after injection activities are complete at each point and thus will not remain in the ground for more than a few days. The locations of the proposed injection wells and points are depicted in Figures 3.2 and 3.3. 3.3.3.3 Substrates The injection fluid that will be deployed at SWMU 69 will consist of a four part emulsion. The injection fluid will consist of approximately 103,000 gallons of water, 5,100 gallons of neat soybean oil, 870 gallons of a pre -mixed soybean oil -in -water emulsion product (containing soybean oil and sodium lactate), and approximately 720 gallons of pH buffering product. The injection fluid was designed specifically for each injection area at SWMU 69 by first calculating the geometric and hydraulic properties of the intended injection areas such as the cross sectional area, the intended lateral dimensions, volume of pore water present in each area during injection, and the volume of groundwater that will flow through each treatment zone during the intended life expectancy of 5 years. These properties were then used to calculate the hydrogen demand that must be met to deplete competing electron acceptors (e.g., dissolved oxygen and iron reduction and methane production) as well as the hydrogen demand required to reductively dechlorinate the contaminant mass present at each injection area. A safety factor of 5 was then applied to 3-8 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc develop a conservative hydrogen loading requirement that is sufficient to deplete all known electron acceptors as well as any potential unknown or unquantifiable inefficiencies or electron consumers. The total hydrogen demand was then converted to substrate demand by dividing the hydrogen demand (in moles of molecular hydrogen) by the production capacity of the sum of the individual electron donors to be applied at SWMU 69. The resulting substrate donor demand and the hydraulic characteristics of each injection area were then used to design the actual injection fluid for each injection area.. The design calculations for each injection area are presented in Appendix A and are summarized in Table 3.1. Neat Soybean Oil Food -grade soybean oil and liquid lecithin will be obtained from a commercial supplier such as Solae, Inc. of Fort Wayne, Indiana. Vegetable oil and lecithin are food - grade materials extracted from soy beans and are used in the food industry for a wide variety of applications. A soybean oil -lecithin mixture with a ratio of 40 pounds soybean oil to 1.0 pound lecithin will be prepared by the vendor prior to shipment to Fort Bragg. Pure soybean oil/lecithin emulsion will be shipped to the site in 1,900 pound (243 gallon) totes or in bulk tanker trailers. Soybean' oil is relatively insoluble in water, thus lecithin is added as an emulsification agent so that the soybean oil can be emulsified with water prior to injection. This emulsification step is taken to increase the injection volume (e.g., 1 part oil and 9 parts water) without increasing the vegetable oil volume. The result is that a relatively small volume of vegetable oil (2,515 gallons) can be distributed into a relatively large volume of aquifer matrix (approximately 200,000 cubic feet). This will distribute -.vegetable oil such that the vegetable oil occupies only a small portion (2.6 perce4y of the interstitial void spaces of the aquifer matrix. In this way, a flow -through treatment bio-barrier is developed that allows groundwater to continue to flow through the treatment cell, bringing dissolved contaminant mass with it for treatment within the treatment zone. After injection the vegetable oil -in -water emulsion will ultimately break and be distributed as small droplets of oil trapped within the aquifer matrix. This entrapped oil does not migrate with advective groundwater flow, rather it remains in place as a relatively immobile, slowly soluble, long-term source of organic carbon. Soybean Oil -in -Water Emulsion Product A portion of the soybean oil loading that will be injected at SWMU 69 will be added in the form of a pre -emulsified soybean oil -in -water emulsion product. This product will be shipped to Fort Bragg as a pre-processed micro -emulsion with an oil droplet size of less than one micron which is considerably smaller than the 10 to 20 micron median droplet size of the field mixed emulsion discussed above. The extremely small droplet size of the emulsion product allows the soybean oil associated with this product to travel short distances in the direction of groundwater flow after injection. The travel distance is typically on the order of 20 to 50 feet depending on the groundwater flow velocity and the mean pore throat size of the soil matrix. It is expected that the migration distance at Fort Bragg will be toward the upper end of that range due to the relatively high groundwater flow rates observed at SWMU 69. The migration of the emulsion product f 3-9 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc _ F will result in the expansion of the each enhanced bioremediation treatment area, the % extension of the residence time in the treatment area, and increased treatment efficiency. The emulsion product also contains a small amount of sodium lactate that will serve as a source of completely soluble organic carbon to the subsurface. The calculated substrate demand (appendix A) will be completely fulfilled by the soybean oil mass that is being injected. Thus, the sodium lactate mass represents extra organic carbon mass that will likely be used only to condition the groundwater geochemistry ahead of the soybean oil derived organic carbon. pH Buffering Product A pH buffering product consisting of a mixture of proprietary naturally occurring long lasting buffering agents, water, dispersants, and food grade preservatives will be injected into the subsurface at SWMU 69 along with the organic substrates. The pH buffering product will be added to support pH conditions in the near neutral range by neutralizing naturally occurring acidic compounds as well as organic acids produced during the fermentation of the vegetable oil. pH conditions must be supported above approximately pH 6 in order for biotic reductive dechlorination to occur efficiently (Volkering and Pijis, 2004). Injection Water Potable water from a nearby fire hydrant or approved surface water impoundment will be used in conjunction with extracted site groundwater to dilute the organic substrates prior to injection. Potable water . and groundwater will serve as a dispersant for the soybean oil -in -water emulsion as well as a carrier for the pH product. Approximately 97 percent of the total fluid that will be injected at SWMU 69 will be water. The injection fluid will consist primarily of water in order to ensure adequate distribution of the organic substrates to avoid physically clogging soil pore throats with soybean oil or the development of excessive biofouling, which would cause an unacceptable decrease in site soil permeability and result in groundwater flow deflection. It is expected that approximately 50 percent of the makeup water for the injections will consist of potable hydrant or surface water with the remaining consisting of untreated groundwater. However, if groundwater cannot be extracted from existing SWMU 69 wells at a reasonable rate then a larger percentage -of potable water may be used to maintain the project schedule. The makeup water used during the SWMU69 injections will be characterized through VOC analysis (USEPA Method 8260B) and this characterization data will be reported in the corrective measures implementation report. 3.3.3.3 Substrate Preparation and Emplacement Substrate injection activities will begin with the delivery and staging of the organic substrates and the setup of a portable injection system at SWMU 69. The injection system will be shipped to Fort Bragg on; one or two pallets and will be setup in a rental cargo van to protect the.system from inclement weather. The injection system will be staged near existing monitoring well 69MW16S in close proximity to an existing fire hydrant. In the event that the fire hydrant is unavailable for use, surface water from a 3-10 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc n With Associated Calculated Radius of Influence ssociated Calculated Radius of Influence 69MWT� Z 0 100 200 7== Feet 1 inch equals 100 feet SWMU 69 69mW1 SWMU-69 VTIVE MEASURES IMPLEMENTATION PLAN IUBSTRATE INJECTION AREAS I AND 2 j. IT.-BRAGG, NORTH CAROLINA, j 69.MW3 CHECKED BY D. Griffiths FIGURE: DRAFTED BY UMSONS SVMLI FILE -69LAJt35_SubInLAmaI2=d DATE 7112107 nearly approved impoundment will be trucked to the site in a rented or subcontracted water truck. Potable water will be supplied to the injection system by running a high density polyethylene (HDPE) line from the fire hydrant or water truck to a large storage tank (frac tank). The storage tank will be filled periodically during injection and the full tank will serve as the water supply during injection. The water tank will be disconnected from the hydrant or water truck when it is not being filled. The supply line from the hydrant or water truck will be situated such that an air gap of at least twice the supply line diameter is established and maintained in order to prevent back flushing into the hydrant. The air gap will conform to ASME A112.1.2 — 1991; Air Gaps In Plumbing Systems. A second HDPE line will be run from the bottom valve on the storage tank to the substrate blending and mixing system. The organic substrates and the pH amendment product will then be amended into the potable water at the correct dosage rate inline through a series of dosimeters. A static high sheer in -line mixer will be used to emulsify the soybean oil -lecithin mixture and potable water to form an oil -in -water emulsion. This oil -in -water emulsion will then be pumped to each injection area with an air operated diaphragm pump (or similar) through HDPE conveyance lines. The system that will be staged in the -vicinity of 69MW 16S is depicted in Figure 3.4. Within each injection area (Figures 3.2 and 3.3) site groundwater will be extracted from existing groundwater monitoring wells for re -injection with the oil -in -water emulsion being piped from the 69MW16S staging area. Submersible pumps will be temporarily installed in one or two monitoring wells (depending on the injection area) to supply site water for injection. The discharge lines from the submersible. pumps will be tied in to the supply line coming from the injection system at 69N4W 16S through a manifold consisting of valves and flow meters designed to measure flow from the groundwater extraction pumps and flow coming from the injection system (Figure 3.5). The mixtures of site groundwater and potable water will be different for each injection area and will depend on the rate at which groundwater can be extracted from the formation. However, the final mixture of organic substrate and water will conform to the design calculations summarized in Table 3.1 and presented in Appendix A. After the oil -in -water emulsion from the injection system has been diluted with site groundwater it will be injected into a combination of temporary injection wells and injection points. It is expected that the total oil -in -water emulsion flow (10 to 20 gallons per minute [gpm]) will be split so that substrate can be injected into two to four injection locations at the same time (5 to 10 gpm per location). Substrate injection will start at each location at a relatively low rate for the first 5 to 10 minutes to ensure that all aspects of the system are in order. During that period., system pressures will be monitored and flow rate adjustments made as needed to avoid excessive pressure which could constitute a health and safety hazard. Removal of all air from the system will be ensured by checking the air release vents installed on each of the injection location risers. Once this initial volume of substrate is injected, the injection rate will be increased to the maximum rate possible without exceeding safe operating pressures or the overburden pressure of the formation (<40 pounds per square inch [psi]). After the appropriate volume of the emulsion has been injected into the subsurface the emulsion flow will be 3-15 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CM1P\fina1\Fina1 Fort Bragg SWMU69 CM1P.doc Fire Hydrant/ Water Truck Flow I Meter LEGEND ® BALL VALVE DOSIMETER I PRESSURE GAGE 20,000 gallon Frac Tank * NOTE: An airgap will be maintained per ASME All 2.1.2 as a back flow prevention measure. ti' Diaphrag Pump Neat Soybean Oil pH Buffer Product I In -Line Mixer I TITLE 5oyoean Oil Emulsion SWMU-69 ITo Infection rea �' CORRECTIVE MEASURES IMPLEMENTATION PLAN SUBSTRATE BLENDING AND MIXING SYSTEM LOCATION FT. BRAGG, NORTH CAROLINA CHFCKFD BY I D. Griffiths PARSONS 9110/07 sl 3.4 From Mixin" System LEGEND ® BALL VALVE T PRESSURE GUAGE lbo lydf� �.�� 0i TITLE Injection Point 1 Injection Point Injection Point Injection Point SWMU-69 CORRECTIVE MEASURES IMPLEMENTATION PLAN SUBSTRATE INJECTION SYSTEM LOCATION FT. BRAGG, NORTH CAROLINA CHECKED BY I D. Gdf ffis PARSONS (FILE I draw%745446 SI Svslem.cdd 3.5 J-1 / stopped and system pressure will be reduced to zero prior to disconnecting any injection -- lines. Assuming the volumes of emulsion/water mixture presented in Table 3.1 can be successfully injected into the formation equally and radial along the entire length of each injection screen interval, and assuming 25 percent effective porosity in the subsurface, this should provide a column of substrate (evenly distributed as droplets throughout the aquifer material) approximately 11 to 12 feet in diameter around each substrate injection location. The effective oil saturation in the subsurface after injection is complete is targeted at approximately 2.6 percent of the effective aquifer matrix porosity. During the course of injection, downgradient wells will be visually monitored to check for emulsion breakthrough. After the process has been completed, the presence of phase -separated oil emulsion in the substrate injection wells and the impact on the groundwater table elevation will be measured with an oil -water interface probe. The presence of vegetable oil or vegetable oil emulsion in nearby wells will also be monitored visually by collecting samples with a clear polyethylene bailer. 3.3.4 Site Restoration After well installation and substrate injection activities are complete any areas that were disturbed by these activities will be returned to their pre -mobilization state. It is expected that site restoration activities will be limited to filling in ruts and planting grass seed and removal of silt fencing. Major disturbances are not expected because off -road vehicle usage will be limited to a pickup truck mounted direct push drilling rig and potentially a small site support vehicle. 3.3.5 Final Site Survey After well installation and substrate injection'activities are complete all well locations will be surveyed. The new permanent monitoring well location will be surveyed by a state licensed land surveyor while the injection well locations will be surveyed by Parsons using a global positioning system (GPS) or by taping from existing well locations. In addition, well completion records for the two new permanent monitoring wells will be completed and submitted to Fort Bragg DPW. All new well location data will be presented in the Corrective Measures Implementation Report (CMIR). 3.4 PERFORMANCE MONITORING 3.4.1 Groundwater Monitoring Well Network, Frequency, and Parameters The groundwater monitoring well network at SWMU 69 will be monitored semi- annually for the first year following injection to document the short term effectiveness of the enhanced bioremediation remedial approach. The current, naturally occurring, geochemical conditions at SWMU 69 are aerobic. Thus, it is expected that it will take at least six months for the injected substrate to establish anaerobic conditions necessary for biotic reductive dechlorination to occur: After anaerobic conditions are established it typically takes at least 6 to 12 additional months to establish the proper microbial r i 3-18 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc I T population necessary for biotic reductive dechlorination. Therefore, a more frequent sampling schedule during the first year following injection is unnecessary. Approximately six to eight weeks following injection an abbreviated groundwater sampling round will be conducted at SWMU 69 to determine if organic substrate has been distributed adequately within each of the five treatment areas. Monitoring wells and injection wells in each injection area will be sampled for TOC, geochemical parameters, and pH. Groundwater will not be analyzed for VOCs because it is unlikely that the injected substrate will have impacted VOC concentrations immediately after injection. A proposed monitoring program for this substrate distribution sampling event is summarized in Table 3.2. During the first year following substrate injection groundwater from wells in the vicinity of the carbon substrate injection areas will be sampled and analyzed for VOCs, TOC, geochemical parameters and pH. In addition, several of the temporary injection wells will also be sampled to monitor geochemical and contaminant conditions within the injection areas. Results of the groundwater sampling will be used to evaluate the effectiveness of the enhanced anaerobic bioremediation application. A proposed monitoring program for the first year following injection is summarized in Table 3.3. After the frst year following substrate injection groundwater sampling events will be conducted annually to .document the effectiveness of the remedial action. The location and sampling frequency of wells for performance sampling will be selected based on evaluation of the results of the previous year's performance sampling. Therefore, the w year 2 monitoring program will be presented in the first annual report to be prepared following the completion of the first year of performance monitoring. "Over the first 10 years, it is anticipated that some of the interior wells may be mQved -to ' a biennial sampling frequency. However, wells near residential areas (e.g., 69MW12, 69MW18D, 69MW21D, and 69MW23 [new well]) may remain on an annual sampling frequency. In addition, Monitoring wells installed in the Cape Fear Aquifer (69MW8, 69MW21C, and 69MW22C) will be sampled on a biennial (once every two years) schedule to ensure that these well locations remain unimpacted by contaminants related to SWMU 69. Groundwater sampling activities will be conducted in accordance with the final project sampling and analysis plan/quality assurance program plan (SAP/QAPP) (Parsons 2007c). 3.4.2 Surface Water Monitoring Locations, Frequency and Parameters A total of two surface water sampling locations in the unnamed tributaries to Young Lake will be sampled on the same frequency as the majority of the monitoring wells at SWMU 69 (e.g., semi-annually for the first year after injection). The historic surface water sampling location 69SW8, located adjacent to injection area 5 (Figure 3.1), will be sampled as part of the SWMU 69 long term monitoring program (LTM). In addition, a new surface water sampling location will be established at the confluence of the two unnamed tributaries to Young Lake, in the vicinity of injection area 3, (Figure 3.1) and sampled as part of the SWMU 69 LTM program. The new surface water sampling location will be labeled 69SW10. • 1 3-19 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CM1P.doc Location Identifier Monitoring Well Installation Water Level, Measurement Groundwater Analyses VOCs' .'(SW8260B) Methane, Ethane, Ethene Nitrate+ Nitrite (E300.1) Total Organic Carbon (SW9060M) _ Well Llead Analysesh'. Mobile Lab Analyses`' Groundwater Monitoring Wells. 69MW l t 69MW6 t - 69MW8 t . 69MW9 t " 69MW10 69MW12 69MW 14S t 69MW16S t t i t 69MW17S t . 69MW18D 69MW 19D 69MW21 C t 69MW2ID i 69MW22C . 69MW23 x i Tem oran, Injection ells Area=1 X i t Area-2. i TABLE 3.3 YEAR ONE EFFECTIVENESS MONITORING PROGRAM SWMU69 FORT BRAGG, NORTH CAROLINA Location Identifier Monitoring Well Installation Sampling Frequency Water Level Measurement Groundwater Analyses VOCsd SW8260B) Methane, Ethane, Ethene Nitrate + Nitrite E300.1) Total Organic Carbon SW9060M) Well Head Analysesb� Mobile Lab Analyses Groundwater Monitorin Wells 69MW 1 semi-annual I 1 1 69MW6 semi-annual I 1 69MW8 bi-annual 1 I 1 69MW9 semi-annual 1 I 1 69MW 10 semi-annual I 1 l I 1 1 1 69MW 12 semi-annual I 1 1 1 1 69MW14S semi-annual I 69MW16S semi-annual I I I l ] I 1 69MW 17S semi-annual 1 1 1 69MW18D semi-annual 1 I t 1 1 I I 69MW 19D semi-annual I 1 1 1 1 I 1 69MW21C bi-annual I I 1 69MW21D semi-annual I 69MW22C' bi-annual 69MW23 X semi-annual 1 1 1 TemporaryInjection Wells Area -I X semi-annual I 1 1 1 I I I I Area-2 X semi-annual 1 1 I 1 1 I 1 Area-3 X semi-annual I 1 1 1 1 I 1 Area-4 X semi-annual 1 1 1 I 1 1 I Area-5 X semi-annual I 1 I 1 1 I I Surface Water M nitoring Locations 69SW8 1 69SW IO 1 SUBTOTALS 19 1 21 1 10 1 10 1 12 1 19 1 12 QA/QC Duplicates 2. I 1 1 I I MS 2 MSD 2 JTrip Blanks 1 TASK TOTAL 28 11 I l 13 20 I3 p1 Volatile organic compounds (VOCs) to include aromatic and chlorinated aliphatic hydrocarbons. N Well head analyses include dissolved oxygen, oxidation-reduction potential, pH, temperature, and conductivity. ` Mobile lab analyses include carbon dioxide, alkalinity, ferrous iron, and manganese. This well'was most recently sampled in February 2007. Thus, it will not be sampled again until Spring 2009. S:\ES\itemed\745446 Fort Bragg PB020010 SWMU-69\CMIP\fnal\Table 3.3.xls 3-21 Surface water sampling activities will be conducted in accordance with the final _ project SAP/QAPP (Parsons 2007c). 3.4.3 Performance Evaluations The performance of the enhanced bioremediation application at SWMU 69 will initially be evaluated annually. If the long term monitoring program sampling frequency is reduced to less than annual, performance evaluations will be conducted on the same frequency as the sampling schedule. The performance evaluation at SWMU 69 will start with an assessment of contaminant concentrations over time. Contaminant concentration trends are the primary line of evidence for determining the effectiveness of the SWMU 69 application. If contaminant concentrations in groundwater decrease over time, the SWMU 69 remedial application can be considered to be successful. The second step in evaluating the effectiveness of an enhanced bioremediation application is to evaluate the concentrations of parent compounds (TCE) and reductive dechlorination daughter products (cis-1,2-DCE, VC, and ethene). If biotic reductive dechlorination is occurring then the concentration and molar fraction of the parent compound will decrease while the concentrations and molar fractions of daughter products will increase. The presence and relative molar fractions of the individual daughter products will indicate whether partial or complete reductive dechlorination is occurring. During the first year after substrate injection it is expected that at least partial _ reductive dechlorination of TCE to cis-1,2-DCE will occur. However, more complete reductive dechlorination to VC and ethene may not occur until up to 2 years after injection. The demonstration of partial reductive dechlorination, coupled with reduced TCE concentrations during year one will be interpreted to indicate that the SWMU 69 enhanced bioremediation application successfully induced reductive dechlorination. It should be noted that VC is extremely unstable under aerobic geochemical conditions (the natural geochemical conditions at SWMU 69) because VC is readily degraded through aerobic oxidation. Thus, while VC may be produced in the injection areas through biotic reductive dechlorination, the VC mass will be rapidly oxidized as soon as it migrates outside of the anaerobic zone established around the injection area. In addition, only very low concentrations of VC and ethene are expected to be produced at SWMU 69 because TCE is present at very low concentrations. Within a closed system (e.g., a laboratory setting) the dechlorination of 25 µg/L of TCE would only produce 12 µg/L of VC and 5 µg/L of ethene. In a natural system it is unlikely that these low concentrations of VC or ethene would ever be detected because these compounds are extremely volatile and reactive. Thus, the absence of detectable concentrations of VC and ethene at SWMU 69 will not indicate that reductive dechlorination is not occurring. The third step in evaluating an enhanced bioremediation application involves the evaluation of the geochemical data to determine what geochemical conditions are present at the site and whether sufficient organic substrate remains to support the anaerobic geochemical conditions necessary for biotic reductive dechlorination. TOC concentrations are evaluated to determine if sufficient organic carbon remains. TOC 3-22 SAES\Remed\745446 Fort Bragg PBC\200.10 SWMU-69\CMP\fina1\Fina1 Fort Bragg SWMU69 CMP.doc - concentrations greater than 20 milligrams per liter (mg/L) have been interpreted by the USEPA to be necessary to support anaerobic geochemical conditions and reductive dechlorination (USEPA, 1998). In addition, dissolved oxygen, oxidation-reduction potential, nitrate/nitrite, ferrous iron, methane, and manganese data will be reviewed to determine what terminal electron accepting processes (TEAPs) are actually occurring at SWMU 69. This data will help to determine how much of the organic substrate is being consumed by processes other than `reductive dechlorination and will lead to a determination of how long the substrate will last in the subsurface. The final step in evaluating the enhanced bioremediation at SWMU 69 will be to review the pH data. Biotic reductive dechlorination has been shown to occur most rapidly under pH neutral conditions (6 to 8). In addition, biotic reductive dechlorination does not occur under acidic conditions (ph less than 6) due to the pH sensitivity of the microorganisms involved in the reductive dechlorination process (Volkering and Pijls, 2004). If pH conditions become more acidic than pH 6 during the course of this application (due to the depletion of natural and added buffering capacity) then complete reductive dechlorination may slow down until the buffering capacity is replaced. The following conditions will indicate a successful remedy: • The TOC concentration in each injection area (as indicated by data collected from the temporary injection wells) is greater than 20 mg/L. y Declining TCE concentration trends in the injection area monitoring wells (e.g., 69MW10, 69MW16S, 69MW12, 69MW18D, 69MW19D, and 69MW21D). ,f 3.4.4 Performance Monitoring Program Optimization The SWMU 69 performance monitoring program will be evaluated annually to determine if the program can be optimized such that only data that is of value and directly contributes to future decisions are collected. Any proposed changes to the monitoring program will be discussed and approved by the Army and NCDENR prior to implementation. 3.5 CONTINGENCY PLANNING Two potential contingencies are planned for possible deployment at SWMU 69. In the event that the analytical data (VOCs and geochemistry) indicate that anaerobic geochemical conditions appropriate for biotic reductive dechlorination have been established but that biotic reductive dechlorination is not occurring then a bioaugmentation culture may be injected into the SWMU 69 injection areas in an effort to emplace a microbial population known to be capable of reductive dechlorination, thereby inducing reductive dechlorination. This contingency will be deployed if all of the following conditions are met: • DO is consistently less than 1 mg/L over multiple sampling rounds. • ORP is less than -100 mV (indicative of moderately to strongly reducing conditions) over multiple sampling rounds. 3-23 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc • TOC concentration is above 50 mg/L in the area being considered for bioaugmentation. • TCE concentration trends increase or remain stable over multiple sampling rounds beyond the first year of long term monitoring. • Daughter products (cis-1,2-DCE and/or VC and/or ethene) are not detected. The second contingency relates to the early depletion of the injected organic substrate. If geochemical data indicates that the organic substrate emplaced during the first injection is becoming depleted before contaminant concentrations are reduced in the hot spots, then additional organic substrate will be injected into the hot spots to extend the longevity of the enhanced bioremediation application. Substrate depletion will be signified by the reduction of TOC concentrations to below 20 mg/L, and the return of aerobic geochemical conditions, in the injection areas. If geochemical data indicates that the substrate is reaching depletion and TCE concentrations in the hot spot(s) remain above TCE concentrations in the remainder of the plume (estimated to be approximately 20 µg/L based on direct push data collected in 2001), then additional organic substrate will be injected. 3.5.1 Bioaugmentation Solution Preparation and Injection In the event that bioaugmentation is deemed to be necessary a bioaugmentation culture will be purchased from SIREM Laboratories and mobilized to the site in specially designed sealed shipping containers. An injection system consisting of a groundwater , extraction pump, a transfer pump, an injection pump, and an inline dosimeter as well as various valves, pressure gauges, and flow meters will also be mobilized to the field site. It is expected that less than one liter of bioaugmentation culture will be required for each injection well based on Parsons and Sirem Laboratories' prior experience at other sites. Sirem's general rule of thumb for calculating culture dosage is l part culture per 30,000 parts groundwater in the intended treatment area. The treatment volume for each injection well is approximately 1,780 gallons. Applying a 1:30,000 factor yields a calculated culture volume of approximately 0.25 liters per injection well. Thus, approximately 1.25 liters to 2.0 liters of bioaugmentation culture will be required for each injection area. Upon arrival the injection system will be setup in the injection area to be bioaugmented. A groundwater extraction pump will be installed in a nearby monitoring well to supply makeup water for the bioaugmentation injection. The geochemistry of the groundwater to be extracted will be confirmed to be anaerobic (dissolved oxygen less than 1 mg/L) prior to mixing with the bioaugmentation culture. After the groundwater geochemistry has been confirmed. The groundwater will be extracted, amended inline with culture through a closed system dosimeter, and re -injected into the previously installed small diameter injection wells. The Bioaugmentation process will begin at each injection well by starting the extraction pump, pumping water through the entire injection system, and discharging to the injection well. During this initial phase the system will be bled of all air bubbles and 3-24 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc 4 pockets and all joints and couplings will be inspected for leaks. After the system has been started the dosimeter will be set to add bioaugmentation culture at a rate of I percent of the water flow. Previously extracted groundwater amended with one percent culture will continue to be injected until approximately 0.25 liters of culture have been added. At that point the dosimeter will be shutdown and un-amended groundwater will continue to be injected to improve the subsurface distribution of bioaugmentation culture. Ultimately each injection well will receive approximately 0.25 liters of culture and approximately 250 gallons of water. 3.5.2 Contingency Substrate Injection In the event that a second substrate injection is deemed to be necessary, additional soybean oil and the injection system will be mobilized to the site. The contingency injection will be conducted in exactly the same way as the primary injection except that the contingency injection will be conducted through the previously installed small diameter injection wells only. The scope of the second injection and the substrate loading to be deployed will depend upon conditions present within the treatment areas to re -injected. However, for permitting purposes it is assumed that the contingency injection will be required and that it will involve the injection of approximately %2 of the substrate volumes injected during the primary injection. 3.6 INSTITUTIONAL CONTROLS Administrative controls and groundwater -use restrictions for the SWMU 69 groundwater plume footprint have already been incorporated into the base master plan (BMP). Currently, SWMU 69 is part of a federal installation and is expected to be retained by the federal government for the indefinite future. Groundwater=use restrictions were implemented to prevent the use of the groundwater for potable water and irrigation. References to relevant corrective action documents for this SWMU will also be included in the BMP. The groundwater use restrictions will be maintained in the BMP until North Carolina 21, standards are met or until contaminant concentrations are at such levels to allow for unrestricted land use. A survey plat for the SWMU will be prepared for inclusion in the BMP. The survey plat will indicate the location and dimensions of the SWMU 69 groundwater plume with respect to permanently surveyed benchmarks. The plat will contain a directive that states Fort Bragg's obligation to prohibit use of the groundwater at SWMU 69 in accordance with this CMIP. The previously surveyed groundwater monitoring wells that establish the present extent of groundwater contamination originating from SWMU 69 will be used to establish the perimeter of the SWMU 69 groundwater plume. Institutional controls include the restriction of groundwater use at SWMU 69. Restrictions on groundwater use for consumption and irrigation will be maintained for the life of this remedial action, estimated to be 20 to 60 years. The groundwater -use restrictions will be maintained during the period of ownership by DoD through the BMP. The BMP will be an effective tool for prohibiting installation of drinking water or irrigation wells at the site while property is under DoD ownership. Groundwater is not currently used as a source of drinking water or irrigation at the site. Institutional controls 3-25 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc prohibiting the use of groundwater in the future will be effective at protecting human health from the elevated levels of COCs in the groundwater. The SWMU 69 land use controls (LUCs) also prohibit intrusive activities within this boundary (e.g., excavation, digging, drilling) without an approved health and safety plan, use of proper personal protective equipment, and other necessary precautions. If soil is excavated from within the SWMU 69 plume area it must be properly characterized, classified, and disposed of in accordance with the Resource Conservation and Recovery Act (RCRA), Offsite Disposal Rule (40 Code of Federal Regulations [CFR] 300.400). Use of groundwater extracted from within the LUC boundary for potable or agricultural use is prohibited. Specific examples of prohibited uses include drinking, irrigation, fire control, and dust control. Dewatering of excavations or trenches is be allowed within the SWMU 69 LUC boundary unless contaminated water is properly managed in accordance with applicable state and federal regulations. It is expected that the proposed land use controls will effectively minimize the potential for any contaminant impacts to potential receptors given that the expected future land use for the SWMU 69 area is much as the current land use is. The future land use is expected to be a combination of vehicle parking and storage in the currently fenced vehicle storage area, an electrical substation and associated power lines, etc and wetlands and/or undeveloped wooded and grass covered areas. 3-26 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc SECTION 4 REPORTING AND DOCUMENTATION 4.1 CORRECTIVE MEASURES IMPLEMENTATION REPORT A CMIR will be issued at the completion of the substrate injection activities at SWMU 69. The CMIR will present all field activities completed at SWMU 69, any field data collected during the installation of the corrective action, and any deviations from the final SWMU 69 CMIP. The CMIR will also present data pertaining to the wells that were used for groundwater extraction, extraction rates, and the total volume removed from each well. 4.2 PERFORMANCE EFFECTIVENESS REPORTS An annual performance effectiveness report will be issued to present the results of the sampling events collected during the previous calendar year. If the monitoring frequency is reduced, the frequency of progress reporting will be reduced as well to coincide with monitoring events. Performance effectiveness reports will present all data collected during the subject reporting period (in accordance with the project.. SAP/QAPP), an assessment of contaminant concentration trends at each performance monitoring well, an assessment of the effectiveness of the remedial action implemented at SWMU 69, and recommendations for any changes to the performance monitoring program for the following reporting period. Recommended elements of the evaluation report for this site include: • A summary of site activities. An evaluation of new data and comparisons with previous data and established performance criteria, which would consist of presentation of the following: — Data in tabular format; — Graphs (e.g., contaminant concentration versus time for individual wells); — Figures (contaminant contours); and — Progress towards achieving remediation goals. An evaluation of need for implementation of additional remedial phases and/or contingency plans. 4-1 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc • Conclusions. • Recommendations. 4.3 PERIODIC REMEDY REVIEWS This site is managed by the Army under the Department of Defense (DoD) Defense Environmental Restoration program (DERP). Paragraph 23.2 of the DoD DERP guidance (DoD, 2001) specifies that periodic remedy reviews be conducted at least every 5 years to ensure that the selected remedy continues to protect human health and the environment. Thus, the remedial action at SWMU 69 will be reviewed at least every five years. The first review will be conducted within approximately 5 years of the selected remedy installation (estimated to be during the spring of 2013). 4-2 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CM1P\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc SECTION 5 REFERENCES Cohen, R.M., and J.W. Mercier. 1993. Dense Non -Aqueous Phase Liquid Site Evaluation. CRC Press, Inc. Boca Raton, Florida. Kearney, A. T., Inc., and DPRA Inc., 1988, Interim Facility Assessment Report, Fort Bragg Military Reservation: United States Environmental Protection Agency Region 4, Contract No. 68-04-7038. North Carolina Department of Environment and Natural Resources [NCDENR]. 2002. Groundwater Quality Standards, 15A NCAC 02L.0202, available at <http://gW.ehnr.state.nc.us/ADA_Webpage/Adobe/gwStandards.l df>. Parsons Infrastructure and Technology Group (Parsons), 2007a. Final Corrective Measures Study for SWMU 69 Jeep Dismantling Area. Fort Bragg, North Carolina. May Parsons, 2007b. Final Accident Prevention Plan for Remedial Services at FortBragg, NC. June. Parsons, 2007c. Draft Project Sampling and Analysis Plan/Quality Assurance Plan. March. US Army Corps of Engineers [USACE]. 2003. Savannah District, Site Conceptual Model Report for the Supplemental RFI Investigations of SWMU 69, Fort Bragg, NC, August USACE. 2006. Savannah District, Draft Site Conceptual Model Report for the Supplemental RFI Investigations of SWMU 69, Fort Bragg, NC, May U.S. Environmental Protection Agency (USEPA) Region 4. 1996b. Supplemental Guidance to RAGS. Region 4. Bulletins, Human Health Risk Assessment, November. USEPA. 1998. Technical Protocol for Evaluating Natural Attenuation of Chlorinated Solvents in Groundwater: EPA/600/R-98/128, September 1998. http://www.epa.gov/ada/reports.html. U.S. Geological Survey (USGS), RCRA Facility Investigation at Operable Unit 4, Fort Bragg Installation Restoration Program, Fort Bragg, North Carolina, Volume I, dated April 1999. 1 5-1 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc Volkering, F. and Pijls, C. 2004. Factors Determining Reductive Dechlorination of cis- 1,2-DCE at PCE Contaminated Sites. Proceedings of the Fourth International Conference on Remediation of Chlorinated and Recalcitrant Compounds (Monterey, CA; May 2004). Paper 3D-10. Columbus, OH: Battelle Press. 5-2 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIP\fina1\Fina1 Fort Bragg SWMU69 CMIP.doc APPENDIX A SUBSTRATE LOADING CALCULATIONS S:\ES\Remed\745446 Fort Bragg PBC\20010 MMU-69WMIMiinal\Final Fort Bragg SWMU69 CMIP.doc This page intentionally left blank TABLE A-1 INJECTION PROTOCOL SUMMARY SWMU-69 FORT BRAGG, NORTH CAROLINA Injection Points Substrate In'ectior Injection Injection Total Emulsion Product(50% oil b weight) Volume Soybean Oil Lactate Well Interval Spacing Points Neat So 1 (gallons) ID feet (feet) (gallons) (gallons) (pounds) (pounds) Injection Area-1 35-44 9 10 140 69 1 539 62 672 Injection Area-2 31-40 9 15 210 - 104 809 93 1,008 Injection Area-3 21-30 9 15 210 104 809 93 1,008 Injection Area-4 15-35 9 10 350 173 1348 154 1,505 Injection Area-5 31-40 9 12 168 83 647 74 890 TOTALS: 62 1,078 1 533 1 4,152 476 5,083 NOTES: Sodium Lactate Product 1. Assumes WillClear sodium lactate product is 60 percent sodium lactate by weight 2. Molecular weight of sodium lactate (CH3-CHOH-COONa) = 112.06. 3. Molecular weight of lactic Acid (QHsO,) = 90.08. 4. Specific gravity of WillClear Product= 1.323 @ 20 degrees Celsius. 5. Weight of WillClear Product= I I.0 pounds per gallon. 6. Pounds per gallon of lactic acid in product =1.323 x 8.33 lb/gal HZO x 0.60 x (90.08/112.06) = 5.31 lb/gal. NOTES: Vegetable Oil Emulsion Product 1. Assumes emulsion product is 50 percent soybean oil by weight. 2. Soybean oil is 7.8 pounds per gallon. 3. Assumes sepcific gravity of emulion product is 0.96 and that emulsion product is 4 percent sodium lactate 1 [0] 7,862 7,862 11,73! 6945 Total Volume Estimated Injection Effective Radius of Interval Porosity Influence (feet) (percent) (feet) Injection Time at 4 gpm (days) Buffering A ent Makeup Water (gallons) Substrate ( ounds) Water+ Substrate (gallons) allons (pounds) 98 1,058 14,000 5,832 14,896 9 25% 5.4 8 147 1,588 21,000 8,911 22,365 9 25% 5.4 6 147 1,588 21,000 8,911 22,365 9 25% 5.4 6 245 2,646 35.000 13,091 37,065 19 25% 5.8 10 118 1,270 16,800 7,856 17,993 9 25% 5.3 5 755 8,150 107,800 44,601 114,684 Days: 35 Drums Gallons Total Totes Gallons Total Emulsion Product Emulsion Product 1 55 19.6 1 220 4.9 Neat Soybean Oil Neat So bean Oil 1 55 92.4 1 220 23.1 Buttering Agent Buffering Agent I 55 13.6 1 250 3.0 injection summaryids A - j 1/17/2008 TABLE A -I AREA -I INJECTION PROTOCOL SWMU-69 FORT BRAGG, NORTH CAROLINA 1. Treatment Zone Physical Dimensions Width (Perpendicular to predominant groundwater Flow direction) Length (Parallel to predominant groundwater flow) Saturated Thickness Treatment Zone Cross Sectional Area Treatment Zone Volume Treatment Zone Total Pore Volume (total volume x total porosity) Treatment Zone Effective Groundwater Volume (total volume x effective porosity) Design Period of Performance Values 100 Range Units 1-10,000 feet 1-1,000 feet 1-100 feet fill - ft' - gallons - gallons .5 to 5 year 18 9.5 950 17,100 38,383 31,986 5 2. Treatment Zone Hydrogeologic Properties Total Porosity 30% .05-50 Effective Porosity 25% .05-50 Average Aquifer Hydraulic Conductivity 18 .01-1000 ft/day Average Hydraulic Gradient 0.008 0.1-0.0001 ft/ft Average Groundwater Seepage Velocity through the Treatment Zone 0.58 - ft/day Average Groundwater Seepage Velocity through the Treatment Zone 210.2 - ftlyr Average Groundwater Flux through the Treatment Zone 373,591 - gallons/year Soil Bulk Density i 1.65 1.4-2.0 gm/cm' Soil Fraction Organic Carbon (foc) 0.0021 0.0001-0.1 3. Initial Treatment Cell Electron -Acceptor Demand (one total pore volume) A. Aqueous -Phase Native Electron Acceptors Oxygen avg of 4 readings Nitrate Sulfate Carbon Dioxide (estimated as the amount of Methane produced) Concentration (mg/L) Mass (lb) Stoichiomelric demand (wtlwt h2) Hydrogen Demand (lb) Electron Equivalents per Mole 5.5 1.76 7.9 0.22 4 1.3 0.42 10.2 0.04 5 5 1.60 10.6 0.15 8 15.0 4.80 5.5 0.88 8 B. Solid -Phase Native Electron Acceptors Manganese (IV) (estimated as the amount of Mn (II) produced Iron (III) (estimated as the amount of Fe (II) produced) C. Soluble Contaminant Electron Acceptors Tetrachloroethene (PCE) Trchloroelhene (TCE) Dichloroethene (cis-DCE, trans-DCE, and 1,1-DCE) Vinyl Chloride (VC) Carbon Tetrachloride (CT) Trichloromelhane ( or chloroform) (CF) Dichloromelhane (or methylene chloride) (MC) Chloromethane Terachloroethane (1,1,1,2-PCA and 1,1,2,2-PCA) Trichloroethane (1,1,1-TCA and 1,1,2-TCA) Dichloroethane (1,1-DCA and 1,2-DCA) Chloroethane D. Sorbed Contaminant Electron Acceptors (Soil Concentration = Koc x foc x Cgw) Tetrachloroethene (PCE) Trchloroethene (TCE) Dichloroethene (cis-DCE, trans-DCE, and 1,1-DCE) Vinyl Chloride (VC) Carbon Tetrachloride (CT) Trichloromethane (or chloroform) (CF) Dichloromethane (or methylene chloride) (MC) Chloromethane Terachloroethane (1,1,1,2-PCA and 1,1,2,2-PCA) Trichloroethane (1,1,1-TCA and 1.1,2-TCA) Dichloroethane (1,1-DCA and 1,2-DCA) Chloroethane Soluble Competing Electron Acceptor Demand (lb.) 1.3 Sloichiometric Hydrogen Electron Concentration Mass demand Demand Equivalents per (mg/L) (lb) (wt/wt h2) (lb) Mole 1.0 0.32 27.5 0.01 1 5 1.60 55.9 0.03 1 Solid -Phase Competing Electron Acceptor Demand (lb.) 0.04 Stoichiomelric Hydrogen Electron Concentration Mass demand Demand Equivalents per (mg/L) (lb) (wt/wt h2) (lb) Mole 0.010 0.00 20.6 0.00 8 0.022 0.01 21.7 0.00 6 0.000 0.0 24.0 0.00 4 0.000 0.00 31.0 0.00 2 0.000 0.00 19.1 0.00 8 0.000 0.00 19.8 0.00 6 0.000 0.00 21.1 0.00 4 0.000 1 0.00 1 25.0 1 0.00 2 0.000 0.00 20.8 0.00 8 0.000 0.00 22.1 0.00 6 0.000 0.00 24.5 0.00 4 0.000 0.00 32.0 0.00 2 Total Soluble Contaminant Electron Acceptor Demand (lb.)( 0.00 ) Stoichiometric Hydrogen Electron Koc Soil Conc. Mass demand Demand Equivalents per (mug) (mg/kg) (lb) (wt/wt h2) (lb) Mole 263 0.01 0.01 20.6 0.00 8 107 0.00 0.01 21.7 0.00 6 45 0.00 0.00 24.0 0.00 4 3.0 0.00 0.00 31.0 0.00 2 224 0.00 0.00 25.4 0.00 8 63 0.00 0.00 12.3 0.00 6 28 0.00 0.00 21.1 0.00 4 25 11 0.00 1 0.00 1 25.0 1 0.00 1 2 117 0.00 0.00 20.8 0.00 8 105 0.00 0.00 22.0 0.00 6 30 0.00 0.00 25.0 0.00 4 3 0.00 0.0D 32.0 0.00 2 Total Sorbed Contaminant Electron Acceptor Demand (lb.)( 0.00 (continued) Area-1.xls " - 2 1/152008 4. Treatment Cell Electron -Acceptor Flux (per year) A. Soluble Native Electron Acceptors TABLE A-1 Concentration (mg/L) Mass (lb) Sloichiometric demand (wt/wt hZ) Hydrogen Demand (lb) Electron Equivalents per Mole 5.5 17.15 7.9 2.17 4 0.3 1.03 10.2 0.10 5 5 15.59 10.6 1.48 8 ,15 46.76 5.5 8.56 8 Oxygen Nitrate Sulfate Carbon Dioxide (estimated as the amount of Methane produced) Total Competing Electron Acceptor Demand Flax (lb/yr) 12.3 B. Soluble Contaminant Electron Acceptors Tetrachloroelhene (PCE) Trichloroethene (TCE) Dichloroethene (cis-DCE, trans-DCE, and 1,1-DCE) Vinyl Chloride (VC) Carbon Tetrachloride (CT) Trichloromelhane (or chloroform) (CF) Dichloromelhans (or methylene chloride) (MC) Chloromethane Tetrachloroethane (1,1,1,2-PCAand 1,1,2,2-PCA) Trichloroethane (1,1,1-TCA and 1,1,2-TCA) Dichloroethane (1,1-DCA and 1,2-DCA) Chlorcethane Sloichiometric Hydrogen Electron Concentration Mass demand Demand Equivalents per (mg/L) (lb) (wttwt h2) (lb) Mole 0.010 0.03 20.6 0.00 1 8 0.022 0.07 21.7 0.00 6 0.000 0.00 24.0 0.00 4 0.000 0.00 31.0 0.00 2 0.000 0.00 19.1 0.00 8 0.000 0.00 19.8 0.00 6 0.000 0.00 21.1 0.00 4 0.000 0.00 25.0 0.00 2 0.000 0.00 20.8 0.00 8 0.000 0.00 22.1 0.00 6 0.000 0.00 24.5 0.00 4 0.000 0.00 32.0 0.00 2 Total Soluble Contaminant Electron Acceptor Demand Flux (lb/yr)l 0.00 l Initial Hydrogen Demand First Year (lb) 13.65 Total Life -Cycle Hydrogen Demand (lb) 61.69 5. Design Factors and Total Hydrogen Demand Microbial Efficiency Uncertainty Factor 2X - 5X Methane and Solid -Phase Electron Acceptor Uncertainty 2X - 5X Remedial Design Safety Factor (e.g., Substrate Leaving Reaction Zone) 1X - 2X SOLUBLE SUBSTRATE DESIGN FACTOR: 1.0 HRC DESIGN FACTOR: 0.0 SLOW RELEASE EDIBLE OIL DESIGN FACTOR: 5.0 Area -lads A - 3 111 &2008 TABLE A-2 AREA -I INJECTION PROTOCOL SWMU-69 FORT RRACG_ NORT14 CAROT INA Substrate Molecular Formula(gm/mole) Substrate Molecular Weight Moles of Hydrogen Produced per Mole of Substrate Ratio of Hydrogen Produced to Substrate (gm/gm P&P Manual Appendix C Lactic Acid (assuming 100%) C311603 90.1 15 0.3357 2 Molasses (assuming 100% sucrose) C12H22011 342 15 0.0883 8 Fructose (assuming 100%) C61-11206 180 8 0.0895 4 Ethanol (assuming 100%) CZH60 46.1 2 0.0875 2 HRC C391-156039 956 24 0.0506 26 Linoleic Acid (Soybean Oil, Corn Oil, Cotton Oil) C18H3Z0Z 281 12 0.0862 16 Table A-3 Estimated Substrate Requirements for Hydrogen Demand in Table 1, Area 1 noeinn I ifo IvranmIs d_9 Substrate Design Factor Pure Substrate Mass Required to Fulfill Hydrogen Demand (pounds) Substrate Product Required to Fulfill Hydrogen Demand (pounds) Substrate Mass Required to Fulfill Hydrogen Demand (milligrams) Effective Substrate Concentration m /L Lactic Acid 0.0 0 0 0.00E+00 0 Sodium Lactate Product 60 percentsolution 1.0 184 306 1.39E+08 20 Molasses(assuming 60% sucrose by weight) 0.0 0 0 0.00E+00 0 . Fructose Product(assuming 80% fructose by weight) 0.0 0 0 0.00E+00 0 Ethanol Product(assuming 80% ethanol by weight) 0.0 0 0 0.00E+00 0 HRC assumes 40% lactic acid and 40% glycerol by weight) 0.0 0 0 0.00E+00 0 L.inoleic Acid (Soybean Oil, Corn Oil, Cotton Oil 0.0 0 0 1 0.00E+00 1 0 Commercial Vegetable Oil Emulsion Product 60% oil by weight) 5.0 3,576 5,960 1 2.70E+09 1 382 NOTES: Sodium Lactate Product 1. Assumes sodium lactate product is 60 percent sodium lactate by weight. 2. Molecular weight of sodium lactate (CH,-CHOH-COONa) = 112.06. 3. Molecular weight of lactic Acid (C61`1603) = 90.08 . 4. Therefore, sodium lactate product yields 48.4 (0.60 x (90.08/112.06)) percent by weight lactic acid. �� _ A --4 1/15/2008 AREA -I INJECTION PROTOCOL SWMU-69 FORT BRAGG, NORTH CAROLINA Well ID Injection Points Substrate Injection Mixture Total Volume Injection Interval (feet) Estimated Effective Porosity (percent) Radius of Influence feet Injection Time at 4 gpm (hours) Injection Interval feet Injection Spacing (feet) Emulsion Product (50% oil b wei ht Neat So been Oil Buffering Agent Makeup Water (gallons) Substrate (pounds) Water+ Substrate ( allons) Volume (gallons) Soybean Oil (gallons) (pounds) Lactate (ounds) allons) (pounds) (gallons) ( ounds) SWMU691NJI.1 3544 9 14 6.9 53.9 6.2 67 524 10 106 1,400 584 1,491 9 25% 5.4 6.2 SWMU691NJI-2 35.44 9 14 6.9 53.9 6.2 67 524 10 106 I.400 584 1.491 9 25% 5.4 6.2 SWMU691NJI-3 3544 9 14 6.9 53.9 6.2 67 524 10 106 1.400 584 1.491 9 25% 5.4 6.2 SWMU691N114 35.44 9 14 6.9 53.9 6.2 67 524 10 106 1,400 584 1.491 9 25% 5.4 6.2 SWMU691NJI-5 3544 9 14 6.9 6.2 67 524 10 106 1.400 584 1,491 9 25% 5.4 6.2 SWMU691NJ[-6 35-44 9 14 6.9 6.2 67 524 10 106 1.400 584 1.491 9 25% 5.4 6.2 SWMU691NJI-7 3544 9 14 6.9 6.2 67 524 10 106 1.400 584 1,491 9 25% 5.4 6.2 SWMU691NJI-8 3541 9 14 6.9 P53.99 6.2 67 524 10 106 1.400 584 1.491 9 25% 5.4 6.2 SWMU69INJI-9 35.44 9 14 6.9 6.2 67 524 10 I06 1,400 584 1.491 9 25% 5.4 6.2 SWMU691NJI-10 3544 9 14 69 62 67 524 10 106 1400 584 1,491 9 251 5.4 6.2 TOTAL: i 140 69 539 62 672 5,242 98 1,058 1 14,000 1 5,843 14910 9 Dn s: 8 SUBSTRATECONCENTRATIONS Final Percent Substrate by Weight: 5.0% Final Lactic Acid Concentration: 0.5 grams/liter Percent Oil by Volume in Emulsion: 5.3 Final Percent Water by Weight: - 95.0% Final Oil Concentration: 46.6 grams/liter EFFECTIVE TREATMENT ZONE CONCENTRATIONS Design Life (years): 5 Lactic Acid Treatment Zone Concentration (mg/W: 57 Final Vegetable Oil Concentration (mg/L): 371 Treatment Zone Volume+ Groundwater Flux Volume 1,868,980 gallons Percentage orTreatment Zone Volume relative to Volume of Injected Fluid 46.6% (NOTES: Sodium Lactate Product I. Assumes WiIlClear sodium lactate product is 60 percent sodium lactate by weight. 2. Molecular weight of sodium lactate (CI4-CHOH-COONa) = 112.06. .3. Molecular weight of lactic Acid &1`1603) = 90.08. '4. Specific gravity of WiIlClear Product = 1.323 Q 20 degrees Celsius. 5. Weight of WiIlClear Product = 11.0 pounds per gallon. 6. Pounds per gallon of lactic acid in product = 1.323 x 8.33 lb/gal RO x 0.60 x (90.081112.06) = 5.31 lb/gal. NOTES: Fructose Product 1. Assumes fructose product is 80 percent fructose sugar by weight. NOTES: Vegetable Oil Emulsion Product I. Assumes emulsion product is 60 percent soybean oil by weight. 2. Soybean oil is 7.8 pounds per gallon. 3. Assumes se cifie gravity of emulion product is 0.96 and that emulsion product is 4 percent sodium lactate by weight. Drums Gallons Total Totes Gallons Total Emulsion Product Emulsion Product 1 55 2.5 1 220 0.6 Neat Soybean Oil Neat Sovbean Oil 1 55 12.2 1 220 3.1 Sodium Lactate Sodium Lactate I - 55 0.0 1 220 0.0 Area-t.xls t • - 5 111512008 TABLE A-i AREA-2 INJECTION PROTOCOL SWNIU-69 FORT BRAGG, NORTH CAROLINA 1. Treatment Zone Physical Dimensions Width (Perpendicular to predominant groundwater flow direction) Length (Parallel to predominant groundwater flow) Saturated Thickness Treatment Zone Cross Sectional Area Treatment Zone Volume Treatment Zone Total Pore Volume (total volume x total porosity) Treatment Zone Effective Groundwater Volume (total volume x effective porosity) Design Period of Performance Values 150 Range Units 1-10,000 feet 1-1.000 feel 1-100 feet - ft2 - fe - gallons - gallons .51o5 year 26 9.5 1425 37,050 83,162 69.302 5 2. Treatment Zone Hydrogeologic Properties Total Porosity Effective Porosity Average Aquifer Hydraulic Conductivity Average Hydraulic Gradient Average Groundwater Seepage Velocity through the Treatment Zone Average Groundwater Seepage Velocity through the Treatment Zone Average Groundwater Flux through the Treatment Zone Soil Bulk Density Soil Fraction Organic Carbon (foc) 3. Initial Treatment Cell Electron -Acceptor Demand (one total pore volume) 30 % 25 % .0550 .05-50 .01-1000 f /day 0.1-0.0001 fvft - fvday - ftlyr - gallonstyear 1.4-2.0 gm/cma 0.0001-0.1 18 0.008 0.58 210.2 560.387 1.65 0.0021 A. Aqueous -Phase Native Electron Acceptors Oxygen avg of 4 readings Nitrate Sulfate Carbon Dioxide (estimated as the amount of Methane produced) Concentration (mg/L) Mass (lb) Stoichiometric demand (wvwt h2) Hydrogen Demand (lb) Electron Equivalents per Mole 5.5 .3.82 7.9 0.48 4 1.3 0.90 10.2 0.09 5 5 .3.47 10.6 0.33 8 15.0 10.41 5.5 1.91 8 B. Solid -Phase Native Electron Acceptors Manganese (IV) (estimated as the amount of Mn (II) produced Iron (III) (estimated as the amount of Fe (II) produced) C. Soluble Contaminant Electron Acceptors Tetrachloroethene (PCE) Trichloroethene (TCE) Dichloroelhene (cis-DCE, trans-DCE, and 1,1-DCE) Vinyl Chloride (VC) Carbon Tetrachloride (CT) Trichloromethane (or chloroform) (CF) Dlchioromethane (or methylene chloride) (MC) Chloromethane Tetrachlorcethane (1,1,1,2-PCA and 1,1,2,2-PCA) Trichloroethane (1,1,1-TCA and 1,1,2-TCA) Dichloroethane (1,1-DCA and 1,2-DCA) Chloroethane D. Sorbed Contaminant Electron Acceptors (Soil Concentration = Koc x foc x Cgw) Tetrachloroethene (PCE) Trichloroethene (TCE) Dichloroethene (Gs-DCE, trans-DCE, and 1,1-DCE) Vinyl Chloride (VC) Carbon Tetrachloride (CT) Trichloromelhane (or chloroform) (CF) Dichloromethane (or methylene chloride) (MC) Chloromethane Tetrachloroethene (1,1,1,2-PCA and 1,1,2,2-PCA) Trichloroethane (1,1,1-TCA and 1,1,2-TCA) Dichloroethane (1,1-DCA and 1,2-DCA) Chloroethane Soluble Competing Electron Acceptor Demand Stoichiometric Hydrogen Electron Concentration Mass demand Demand Equivalents per (mg/L) (lb) (wt/wt h2) (lb) Mole 1.0 0.69 27.5 0.03 1 El 15 10.41 55.9 0.19 1 Solid -Phase Competing Electron Acceptor Demand (lb.) 0.21 Stoichiometric Hydrogen Electron Concentration Mass demand Demand Equivalents per (mg/L) (lb) (vWM h2) (lb) Mole 0.000 0.00 20.6 0.00 8 0.023 0.02 21.7 0.00 6 0.000 0.00 24.0 0.00 4 0.000 0.00 31.0 0.00 2 0.000 0.00 19.1 0.00 8 0.000 0.00 19.8 0.00 6 0.000 0.00 21.1 0.00 4 0.0o0 1 0.00 25.0 0.00 1 2 0.000 0.00 20.8 0.00 8 0.000 0.00 22.1 0.00 6 0.000 0.00 24.5 0.00 4 0.000 0.1 32.0 0.00 2 Total Soluble Contaminant Electron Acceptor Demand (lb.)L 0.00 Stoichiometric Hydrogen Electron Koc Soil Conc. Mass demand Demand Equivalents per (mug) (mg/kg) (lb) (wVwt h2) (lb) Mole 263 0.00 0.00 20.6 0.00 8 107 0.01 0.02 21.7 0.00 6 45 0.00 0.00 24.0 0.00 4 3.0 0.00 0.00 31.0 0.00 2 224 0.00 0.00 25.4 0.00 8 63 0.00 0.00 12.3 0.00 6 28 0.00 0.00 21.1 0.00 4 2s 0.00 0.00 1 25.0 0.00 2 117 0.00 0.00 20.8 0.00 8 105 0.00 0.00 22.0 0.00 6 30 0.00 0.00 25.0 0.00 4 3 0.00 0.00 32.0 0.00 2 Total Sorbed Contaminant Electron Acceptor Demand (lb.)I 0.00 I (continued) Area-2.4s A - 6 11115aa08 4. Treatment Cell Electron -Acceptor Flux (per year) A. Soluble Native Electron Acceptors TABLE A-1 Concentration (mg/L) Mass (lb) Stoichiometric demand (wttwt hz) Hydrogen Demand (lb) Electron Equivalents per Mole 5.5 25.72 7.9 3.26 4 0.3 1.54 10.2 0.15 5 5 23.38 10.6 2.21 8 15 70.14 5.5 12.85 8 Oxygen Nitrate Sulfate Carbon Dioxide (estimated as the amount of Methane produced) Total Competing Electron Acceptor Demand Flux (lb/yr) 18.5 B. Soluble Contaminant Electron Acceptors Tetrachloroethene (PCE) Trichloroethene (TCE) Dichloroethene (cis-DCE, trans-DCE, and 1,1-DCE) Vinyl Chloride (VC) Carbon Tetrachloride (CT) Trichloromelhane ( or chloroform) (CF) Dichloromethane (or methylene chloride) (MC) Chloromethane Tetrachloroethane (1,1,1,2-PCA and 1,1,2,2-PCA) Trichloroethane (1,1.1-TCA and 1,1,2-TCA) Dichloroethane (1,1-DCA and 1,2-DCA) Chloroethane Stoichiometric Hydrogen Electron Concentration Mass demand Demand Equivalents per (mg/L) (lb) (wt/wt hZ) (lb) Mole 0.000 0.00 20.6 0.00 1 8 0.023 0.11 21.7 0.00 1 6 0.000 0.00 24.0 0.00 1 4 0.000 0.00 31.0 0.00 1 2 0.000 0.00 19.1 0.00 1 8 0.000 0.00 19.8 0.00 6 0.000 0.00 21.1 0.00 4 0.000 0.00 25.0 0.00 2 0.000 0.00 20.8 0.00 8 0.000 0.00 22.1 0.00 6 0.000 0.00 24.5 0.00 4 0.000 0.00 32.0 0.00 2 Total Soluble Contaminant Electron Acceptor Demand Flux (lb/yr) 0.00 Initial Hydrogen Demand First Year (Ib) 21.49 Total Life -Cycle Hydrogen Demand (Ib) 93.54 5. Design Factors and Total Hydrogen Demand Microbial Efficiency Uncertainly Factor 2X - 5X Methane and Solid -Phase Electron Acceptor Uncertainty 2X - 5X Remedial Design Safety Factor (e.g., Substrate Leaving Reaction Zone) 1X - 2X SOLUBLE SUBSTRATE DESIGN FACTOR: 1 1.0 HRC DESIGN FACTOR: 0.0 SLOW RELEASE EDIBLE OIL DESIGN FACTOR: 5.0 Area 2jds A - 7 1n5/2009 Substrate Molecular Formula Substrate Molecular Welght mlmole Moles of Hydrogen Produced per Mole of Substrate Ratio of Hydrogen .... Produced.to: Substrate (gm/gm P&P Manual Appendix C". ."." Lactic Acid (assuming 100%) ". • C311603 90.1 .15 - 0:3357 2 Molasses (assuming 100% sucrose) C121-122011 .. 342. .15 0.0883 8 Fructose (assuming 100%) C61-11206 180 .8 - 0.0895 4 " Ethan.61 (assuming 100%) C21-160 . 46.1. 2 0.0875 _ _ 2 HRC C361-15e039. 956 24 0.0506 26 Linoleic Acid (Soybean Oil, Corn Oil, Cotton Oil), C161-13202 281. 12 0.0862 16, Table-A-3 Estimated Substrate. Requirements for Hydrogen.Demand in.Table.l, Area'-2 . Substrate Design, Factor Pure Substrate Mass Required to Fulfill Hydrogen Demand_ (pounds) " ..Substrate Product Required_to Fulfill . Hydrogen Demand. ounds Substrate Mass Required to Fulfill Hydrogen Demand milli rams Effective Substrate Concentration m /L Lactic Acid : 0.0" .. 0 .. 0 0.00E+00- 0 - .'. Sodium Lactate Product 60 percent solution '.:. 1.0 279 :.: 464' ' 2.11E+08 20 Molasses(assuming 60%sucrose by weight) 0.0. 0 0 0.00E+00 . 0 Fructose Product(assuming 80% fructose b weight) 0.0'-- '0 0' 0.00E+00 ' 0 Ethanol Product assumin 80% ethanol by weight) 0.0 0 -0 0.00E+00 . _ 0 ' HRC (assumes 40% lactic acid and 40% glycerol by weight) - :. 0.0 0,.-. -0 O.00E+00 . 0. Linoleic Acid (Soybean Oil; Corri Oil, Cotton Oil 0.0. _ 0 0 ' O.00E+00.: 0 .. Commercial Vegetable Oil Emulsion Product(60% oil by weight) 5.0 5;423 . 9,038 4.10E+09. 383 I., atiuo Points Substnitc I-n ectino Mislurc - Total Valumc EatimulcJ Injecliuo. - iojatloo. lojectino -. Emulsion pioducl 5U%nii by xci �htP B.Mring, ' M1lakcup. - Water+. Injection "EOectirc Radius of j 1i Well Interval .Spacing Volume' Su3'bc:in Oil Lacudi Neal Suvhcao0il A^'cot .Water. Substrate Substrate Iolcnel P.omsil2 Inflame o14 gpm _ . . .-. -._ .. -._ �-..___.-._...._..... ".:.:u__.... r......_.:.. r..:.n..:.:. r........a.i r..,n-rs . /fomn' inrrcenrl (fretl - . fhnursl' 1a9 fflm 11��®®®®®®��® TOTAL: 210 too .' 809 93. -Lou% . 7Ji62 ' ' 147 Isa% n.uuu a,rw lz a — SUBSTRATE CONCENTRATIONS - 'Final Percent Substrate by Wcigbtd . 5.0% Final Lactic Acid Cuncentratiaai.gnm:✓litcr Percent Oil by Vultieu. in Emulsiu 5.3 Final Percent Water by Weight: - 95.0% Finul Oil Curt—tratiun:.. ' 46.6 •ramsAiter . EFFECTIVE TREATMENT ZONE CONCENTRATIONS _ Design Life (rean)s : -4.0 - Lactic Add Trcalmeol Zone Cuoceolraliun:(.w0:. _ ' S6 ' Fioul Vegetable Oil Cuocentralian (mIJL)r J6S ireattncor2uocVolumc*CmunJo'atcr Flus Valumc- - 2182'9,4153' ulluns. Perccnta •c of Taalmcnl 7amc Valumc rclativc In Vulumc of ln'eatcd Fluid P..J NOTES: Sudmm Latute ...It I. Assures WillClearsodium lac . wit, induct is 6U percent sodium lactate by IigliL " 2. Mnleculu a cigbi of sodium L•ictmc (CI{-CHOH-COONa).= I 12.06: - 3. Molecularltiight of lactic Acid (CDH40il-9U,U%: - 4. Specific gmdity of Will0c r Produci= 1.323 i1. 26 degrees Celsius. - 5: Weight of WHIClcar Pioduc1= 11.0 pounds per gallon:. 6, Pounds per gall -of lactic acid in pmduct = 1.323s %.33 Ib/gal HO\ u.6n s 190.WVI 12.U6) 5.31 lblgal. NOTES: Fiuctmc Prudud.' - - Dennis Gailous Total " Toles "- Gallons : Told Emulsion Product Emulsion Product I . 55 3.% I 22m 61 Nca(Sdvbcan Oil ' Not Sovbcan Oil ' "1 .55 I%.3 '.I -.'- _226 .� 4.6-. Sadium Lacedc Sodium Lucmlc ...- 1 'SS. .(I.U-.-'-. I' it U.U.' 1: Assunes fructose product is %ll perccllL fructose sugar by, wight.. NOTES: Vcgclablc Oil Emulsion Product L. Assuites cmulsion product is 6u percent so3.bcan oil be ncighl. 2..Saybcmi6ilis7.8.poundsperga110n " 3. Assures se c ific 9taviteofenudidn product is U.96 mid that cmulsion roducl is 4 perceia sodium Iaclale by ss'ci ght.,' TABLE A-1 AREA-3 INJECTION PROTOCOL SWNIU-69 FORT BR4GG, NORTH CAROLINA 1. Treatment Zone Physical Dimensions Values Range Units Width (Perpendicular to predominant groundwater flow direction) 150 1-10,000 feet Length (Parallel to predominant groundwater flow) 26 1-1,000 feet Saturated Thickness 9.5 1-100 feet Treatment Zone Cross Sectional Area 1425 - IF Treatment Zone Volume 37,050 - ft, Treatment Zone Total Pore Volume (total volume x total porosity) 83,162 - gallons Treatment Zone Effective Groundwater Volume (total volume x effective porosity) 69,302 - gallons Design Period of Performance 5 .51o5 year 2. Treatment Zone Hydrogeologic Properties Total Porosity 30% .05-50 Effective Porosity 25% .05-50 Average Aquifer Hydraulic Conductivity 18 .01-1000 ft/day Average Hydraulic Gradient 0.008 0.1-0.0001 ft/ft Average Groundwater Seepage Velocity through the Treatment Zone 0.58 - fl/day Average Groundwater Seepage Velocity through the Treatment Zone 210.2 - ft/yr Average Groundwater Flux through the Treatment Zone 560.387 - gallons/year Soil Bulk Density 1.65 1.4-2.0 gm/cm' Soil Fraction Organic Carbon (foe) 0.0021 0.0001-0.1 3. Initial Treatment Cell Electron -Acceptor Demand (one total pore volume) A. Aqueous -Phase Native Electron Acceptors Oxygen avg of 4 readings Nitrate Sulfate Carbon Dioxide (estimated as the amount of Methane produced) Concentration (mg/L) Mass (lb) Stoichiometric demand (wUwl hz) Hydrogen Demand (lb) Electron Equivalents per Mole 5.5 3.82 7.9 0.48 4 1.3 0.90 10.2 0.09 T 5 5 3.47 10.6 0.33 8 15.0 10.41 5.5 1.91 8 B. Solid -Phase Native Electron Acceptors Manganese (IV) (estimated as the amount of Mn (II) produced Iron (III) (estimated as the amount of Fe (11) produced) C. Soluble Contaminant Electron Acceptors Tetrachloroethene (PCE) Trichloroelhene (TCE) Dichlorcethene (cis-DCE, trans-DCE, and 1,1-DCE) Vinyl Chloride (VC) Carbon Tetrachloride (CT) Trichloromethane (or chloroform) (CF) Dichloromethane (or methylene chloride) (MC) Chloromethane Tetrachloroethane (1,1,1,2-PCA and 1,1,2,2-PCA) Trichloroelhane (1,1,1-TCA and 1,1,2-TCA) Dichioroethane (1,1-DCA and 1,2-DCA) Chloroethane D. Sorbed Contaminant Electron Acceptors (Soil Concentration = Koc x foe x Cgw) Tetrachloroethene (PCE) Trichloroethene (TCE) Dichloroelhene (cis-DCE, trans-DCE, and 1,1-DCE) Vinyl Chloride (VC). Carbon Tetrachloride (CT) Trichloromelhane ( or chloroform) (CF) Dichloromethane (or methylene chloride) (MC) Chloromethane Tetrachloroethane (1,1,1,2-PCA and 1,1,2,2-PCA) Trichloroelhane (1,1,1-TCA and 1,1,2-TCA) Dichloroethane (1,1-DCA and 1,2-DCA) Chloroethane Soluble Competing Electron Acceptor Demand (lb.) 2.8 Stoichiometric Hydrogen Electron Concentration Mass demand Demand Equivalents per (mg/L) (lb) (wt1wt hZ) (lb) Mote 1.0 0.69 27.5 0.03 1 15 10.41 55.9 0.19 1 Solid -Phase Competing Electron Acceptor Demand (lb.) 0.21 Stoichiometric Hydrogen Electron Concentration Mass demand Demand Equivalents per (mg/L) (lb) (wYM hz) (lb) Mole 0.005 0.00 20.6 0.00 8 0.026 0.02 21.7 0.00 6 0.000 0.00 24.0 0.00 4 0.000 0.00 31.0 0.00 2 0.000 0.00 19.1 0.00 8 0.000 0.00 19.8 0.00 6 0.000 0.00 21.1 0.00 4 0.000 1 0.00 25.0 0.00 1 2 0.000 0.00 20.8 0.00 8 0,000 0.00 22.1 0.00 1 6 0.000 0.00 24.5 0.00 1 4 0.000 0.00 32.0 0.001 2 Total Soluble Contaminant Electron Acceptor Demand (lb.) 0.00 _ Stoichiometric Hydrogen Electron Koc Soil Cone. Mass demand Demand Equivalents per (mug) (mg/kg) (lb) (wI/wt hz) (lb) Mote 263 0.00 0.01 20.6 0.00 8 107 0.01 0.02 21.7 0.00 6 45 0.00 0.00 24.0 0.00 4 3.0 0.00 0.00 31.0 0.00 2 224 0.00 0.00 25.4 0.00 8 63 0.00 0.00 12.3 0.00 6 28 0.00 0.00 21.1 0.00 4 25 0.00 0.00 25.0 0.00 2 117 0.00 0.00 20.8 0.00 8 105 0.00 0.00 22.0 0.00 6 30 0.00 0.00 25.0 0.00 4 3 0.00 0.00 32.0 0.00 1 2 otal Sorbed contaminant Electron Acceptor Demand (lb.)[ 0.00 I (continued) Aree-3xts A - 1 t/152008 i 4. Treatment Cell Electron -Acceptor Flux (per year) A. Soluble Native Electron Acceptors TABLE A-1 Concentration (mg/L) Mass (lb) Sloichiometric demand (wttwt hZ) Hydrogen Demand (lb) Electron Equivalents per Mole 5.5 25.72 7.9 3.26 4 0.3 1.54 10.2 0.15 5 5 23.38 10.6 2.21 8 15 70.14 5.5 12.85 8 Oxygen Nitrate Sulfate Carbon Dioxide (estimated as the amount of Methane produced) Total Competing Electron Acceptor Demand Flux (Iblyr) 18.5 B. Soluble Contaminant Electron Acceptors Tetrachloroethene (PCE) Trichloroelhene (TCE) Dichloroethene (cis-DCE, trans-DCE, and 1,1-DCE) Vinyl Chloride (VC) Carbon Tetrachloride (CT) Trichloramethane (or chloroform) (CF) Dichloromethane (or methylene chloride) (MC) Chloromethane Tetrachloroethane (1,1,1,2-PCA and 1,1,2,2-PCA) Trichloroethane (1,1,1-TCA and 1,1,2-TCA) Dichloroethane (1,1-DCA and 1,2-DCA) Chloroelhane Stoichiometric Hydrogen Electron Concentration Mass demand Demand Equivalents per (mg/L) (lb) (wtlwt hz) (lb) Mole 0.005 0.02 20.6 0.00 8 0.026 0.12 21.7 0.01 6 0.000 0.00 24.0 0.00 4 0.000 0.00 31.0 0.00 2 0.000 0.00 19.1 0.00 a 0.000 0.00 19.8 0.00 6 0.000 0.00 21.1 0.00 4 0.000 1 0.00 1 25.0 1 0.00 2 0.000 0.00 20.8 0.00 8 0.000 0.00 22.1 0.00 6 0.000 0.00 24.5 0.00 4 0.000 0.00 32.0 0.00 2 Total Soluble Contaminant Electron Acceptor Demand Flux (Iblyr)1 0.01 1 Initial Hydrogen Demand First Year (lb)l 21.49 Total Life -Cycle Hydrogen Demand (lb)l 93.54 5. Design Factors and Total Hydrogen Demand Microbial Efficiency Uncertainly Factor 2X - 5X Methane and Solid -Phase Electron Acceptor Uncertainty 2X - 5X Remedial Design Safety Factor (e.g., Substrate Leaving Reaction Zone) 1X - 2X SOLUBLE SUBSTRATE DESIGN FACTOR: I 1.0 HRC DESIGN FACTOR: 0.0 SLOW RELEASE EDIBLE OIL DESIGN FACTOR: 1 5.0 Area-3.As A - 1 1 1/15/200a TABLE A-2 AREA-3 INJECTION PROTOCOL SWMU-69 FORT BRAGG, NORTH CAROLINA Substrate Molecular Formula(gm/mole) Substrate Molecular Weight Moles of Hydrogen Produced per Mole of Substrate Ratio of Hydrogen Produced to Substrate (gm/gm P&P Manual Appendix C Lactic Acid (assuming 100%) C3H603 90.1 15 0.3357 2 Molasses (assuming 100% sucrose) C121-122011 342 15 0.0883 8 Fructose (assuming 100%) C61-11206 180 8 0.0895 4 Ethanol (assuming 100%) C21-160 46.1 2 0.0875 2 HRC C391-156039 956 24 0.0506 26 Linoleic Acid (Soybean Oil, Corn Oil, Cotton Oil) C1aH3202 281 12 0.0862 16 Table A-3 Estimated Substrate Requirements for Hydrogen Demand in Table 1, Area 3 Design Life (Years): 4.9 Substrate Design Factor Pure Substrate Mass Required to Fulfill Hydrogen Demand (pounds) Substrate Product Required to Fulfill Hydrogen Demand (pounds) Substrate Mass Required to Fulfill Hydrogen Demand (milligrams) Effective Substrate Concentration m /L Lactic Acid 0.0 0 0 0.00E+00 0 Sodium Lactate Product 60 percent solution 1.0 279 464 2.11E+08 20 Molasses(assuming 60% sucrose by weight) 0.0 0 0 0.00E+00 0 Fructose Product(assuming 80% fructose by weight) 0.0 -0 0 0.00E+00 0 Ethanol Product(assuming 80% ethanol by weight) 0.0 0 0 0.00E+00 0 HRC assumes 40% lactic acid and 40% glycerol by weight) 0.0 0 0 0.00E+00 0 Linoleic Acid (Soybean Oil, Corn Oil, Cotton Oil 0.0 0 0 0.00E+00 0 Commercial Vegetable Oil Emulsion Product 60% oil by weight) 5.0 5,423 9,039 4.10E+09 383 NOTES: Sodium Lactate Product 1. Assumes sodium lactate product is 60 percent sodium lactate by weight. 2. Molecular weight of sodium lactate (CH3-CHOH-COONa) = 112.06. 3. Molecular weight of lactic Acid (C61-1603) = 90.08. 4. Therefore, sodium lactate product yields 48.4 (0.60 x (90.08/112.06)) percent by weight lactic acid. k' 1 �')08 1o41iuoPnints "Substalcln'eetindalixmre' Total Vnlumc-" Estimal'd Injecliuo lojcctiuo' Iojttliuo Ernulsfon Prlduet eMilnil brtrci bt Buffering " Makcup . " Wuter+ lojcctiun. "Effective Radius of ,Time' Well Intcn-d Spacing Volume Sa)'bean Oil. - L.ctale' Neal Sanccan Oil .Acnl Waicr Substrate . Substrle •lni al 'Poasily Innucace at4 upm in. . lfn..n. 1 'rr.•.•n 'Invllnwel /n:illnnui r.n.n�daf A.nmdrl i.ulL�n�l-'hni.ndd rnnllnn�l. rnnnndrl /nwllnn�l '..d l ' frallanxl Ifcell- Incrcentl /fcell- t6norsl I[® I SWMU6911,113-11 IF111111111111�[RA 1 SWMU69 SUBSTRATECONCENiRATIONS' - Fiod Pcrccat Substate by Weight: 5.0 % Flout la clic Acid Cuocenlatino: 0.5 grams/lit.r. Percent Oil he Volume In Emulsiuo:. 5.3 % -' Maul Percent Waferbr Wci Lbe 95.0% Fiad Oil Cutlmalralian: 46.6 gramsAft.r EFFECTIVE TREATMENT ZONE CONCF-NTRATIONS Design Lifc (ycarx):. - 4.9 Lactic Acid Trealntcui tilnc Ca m,mratfud (my/L):. 56 - - - Find Vegetable Oil Cooccntralioo (mg/L):'. 368 ' Trcatmcntbloc Vnlumc+Gmmndwalcr Flux Vniume 2J119.058 •dlooi Perccot.ce nfTrcatmenl time Vnlumc relative to Vnlumc of InjatcJ FIuiJ -' 32:3 % " NOTES: Sodium Lactate Pniduct I.. Asswiics WillClmrsodium luciam product is 6U pcmcnl sodium lacwle br tmigln. 2: Molcculw iecigla ofsodiuul laculc(CH-CHOU-COON.) 0112.06: - 3. Molmulanveiglnof Ixcdc Acid(GH,,OJ-9U.Ug. . 1:. Spmifrc grariiy of Wil[Clcar Product= 1.323 rh 20 degrees Cclsius_ - - 5: Wcigla of WillCieur.Product=.]LUpouildspergallon: - - G. Poatids per gallon of lactic acid in product 1.323 x N.3.: lb/gal 1j0'x 0.60 x (90.08/112.06) 5.31 Ib/gal. NOTES: Fact,,. Priducl - Drums Gallons . _ TomI Toics ..Gallons - Tobd Emulsion Product - Emulsion Product 1 55 3.g - I 221-,' :'1.11-' Ncat.So,ben110il- - NcmSocbcmlOil•- ".1 .55 1113 "'1220 .4A . Sodium Lacww ' - - Sodiu Lacimc ' . 1 15 .0.0 . .1 220 U.0 I, Assumes fruciosc product is SU pciccin fruclosc sugar by mcighL, - NOTES:. Vegciahlc Oil Emulsion Product - - - - I. Assumes mulsion product is 60.perecnt soybean oil by.orighi. 2, Sorbc:uloilis7.8 pounds per gallmt 3:.Asswtus sc ifir meib of crtiulion roduct is 0.96':wd ilcil emulsion roduet is 1 rccia sodium lactate be rrcigbt. TABLE A -I AREA4 INJECTION PROTOCOL SWNIU-69 FORT BRAGG, NORTH CAROLINA 1. Treatment Zone Physical Dimensions Values Range Units Width (Perpendicular to predominant groundwater Flow direction) 90 1-10,000 feet Length (Parallel to predominant groundwater flow) 26 1-1,00D feet Saturated Thickness 20 1-10D feet Treatment Zone Cross Sectional Area 1800 - ff Treatment Zone Volume 46,800 - it, Treatment Zone Total Pore Volume (total volume x total porosity) 105,047 - gallons Treatment Zone Effective Groundwater Volume (total volume x effective porosity) 87.539 - gallons Design Period of Performance 5 .5 to 5 year 2. Treatment Zone Hydrogeologic Properties Total Porosity 30 % .05-50 Effective Porosity 25% .05-50 Average Aquifer Hydraulic Conductivity 18 .01-1000 f /day Average Hydraulic Gradient 0.008 0.1-0.0001 Wit Average Groundwater Seepage Velocity through the Treatment Zone 0.58 - ft/day, Average Groundwater Seepage Velocity through the Treatment Zone 210.2 - ftlyr Average Groundwater Flux through the Treatment Zone 707,857 - gallons/year Soil Bulk Density 1.65 1.4-2.0 gm/cm" Soil Fraction Organic Carbon (foc) 1 0.00211 0.0001-0.1 3. Initial Treatment Cell Electron -Acceptor Demand (one total pore volume) A. Aqueous -Phase Native Electron Acceptors Oxygen avg of 4 readings Nitrate Sulfate Carbon Dioxide (estimated as the amount of Methane produced) Concentration (mg/L) Mass (lb) Stoichiometric demand (wt/wt h2) Hydrogen Demand (lb) Electron Equivalents per Mole 5.5 4.82 7.9 0.61 4 1.3 1.14 10.2 0.11 5 5 4.38 10.6 0.42 8 15.0 13.15 5.5 2.41 8 B. Solid -Phase Native Electron Acceptors Manganese (IV) (estimated as the amount of Mn (II) produced Iron (III) (estimated as the amount of Fe (II) produced) C. Soluble Contaminant Electron Acceptors Tetrachloroethene (PCE) Trichloroethene (TCE) Dichloroethene (cis-DCE, trans-DCE, and 1,1-13CE) Vinyl Chloride (VC) Carbon Tetrachloride (CT) Trichloromelhane ( or chloroform) (CF) Dichloromethane (or methylene chloride) (MC) Chloromethane Tetrachloroethane (1,1,1,2-PCA and 1,1,2,2-PCA) Trichloroethane (1,1,1-TCA and 1,1,2-TCA) Dichloroethane (1,1-DCA and 1,2-DCA) Chloroethane D. Sorbed Contaminant Electron Acceptors (Soil Concentration = Koc x foe x Cgw) Tetrachloroethene (PCE) Trichloroelhene (TCE) Dichloroethene (cis-DCE, trans-DCE, and 1,1-DCE) Vinyl Chloride (VC) Carbon Tetrachloride (CT) Trichloromethane ( or chloroform) (CF) Dichloromethane (or methylene chloride) (MC) Chloromethane Tetrachloroethene (1.1,1,2-PCA and 1,1,2,2-PCA) Trichloroelhane (1,1,1-TCA and 1,1,2-TCA) Dichloroethane (1,1-DCA and 1,2-DCA) Chloroethane Soluble Competing Electron Acceptor Demand (lb.) 3.5 Stoichiometric Hydrogen Electron Concentration Mass demand Demand Equivalents per (mg/L) (lb) (wt/wt h2) (lb) Male 1.0 0.88 27.5 0.03 1 15 13.15 55.9 0.24 11 1 Solid -Phase Competing Electron Acceptor Demand (lb.) 0.27 Stoichiometric Hydrogen Electron Concentration Mass demand Demand Equivalents per (mg/L) (lb) (WtW h2) (lb) Mole 0.005 0.00 20.6 0.00 8 0.054 0.05 21.7 0.00 6 0.000 0.00 24.0 0.00 4 0.000 0.00 31.0 0.00 2 0.000 0.00 19.1 0.00 8 0.000 0.00 19.8 0.00 6 0.000 0.00 21.1 0.00 4 0.000 0.00 25.0 0.00 2 0.000 0.00 20.8 0.00 8 0.000 0.00 22.1 0.00 6 0.000 0.00 24.5 0.00 4 0.000 0.00 32.0 0.00 2 Total Soluble Contaminant Electron Acceptor Demand (lb.)i 0.00 I Stoichiometric Hydrogen Electron Koc Soil Cone. Mass demand Demand Equivalents per (mug) (mg/kg) (lb) (wbW h2) (lb) Mole 263 0.00 0.01 20.6 0.00 8 107 0.01 0.06 21.7 0.00 6 45 0.00 0.00 24.0 0.00 4 3.0 0.00 0.00 31.0 0.00 2 224 0.00 0.00 25.4 0.00 6 63 0.00 0.00 12.3 0.00 6 28 0.00 0.00 21.1 0.00 4 25 0.00 1 0.00 25.0 0.00 2 117 0.00 0.00 20.8 0.00 8 105 0.00 0.00 22.0 0.00 6 30 0.00 0.00 25.0 0.00 1 4 3 0.00 0.00 32.0 0.00 1 2 Total Sorbed Contaminant Electron Acceptor Demand (lb.) I O.00 I (continued) Area-- revlsed.AB A - 14 1n52008 4. Treatment Cell Electron -Acceptor Flux (per year) A. Soluble Native Electron Acceptors TABLE A-t 15 88.60 5.5 .23 Oxygen Nitrate Sulfate Carbon Dioxide (estimated as the amount of Methane produced) B. Soluble Contaminant Electron Acceptors Tetrachloroethene (PCE) Trichloroelhane (TCE) Dichloroethene (cis-DCE, trans-DCE, and 1,1-DCE) Vinyl Chloride (VC) Carbon Tetrachloride (CT) Trichloromethane (or chloroform) (CF) Dichloromethane (or methylene chloride) (MC) Chloromethane Tetrachloroethane (1,1,1,2-PCA and 1,1,2,2-PCA) Trichloroethane (1,1,1-TCA and 1,1,2-TCA) Dichloroethane (1,1-DCA and 1,2-DCA) Chloroelhane Sloichiometric Hydrogen Electron Concentration Mass demand Demand Equivalents per (mg/L) (lb) (wtlwt hz) (lb) Mole 0.005 0.03 20.6 0.00 1 8 0.054 0.32 21.7 0.01 6 0.000 0.00 24.0 0.00 4 0.000 0.00 31.0 0.00 2 0.000 0.00 19.1 0.00 8 0.000 0.00 19.8 0.00 6 0.000 0.00 21.1 0.00 4 0.000 0.00 1 25.0 0.00 2 0.000 0.00 20.8 0.00 8 0.000 0.00 22.1 0.00 6 0.000 0.00 24.5 0.00 4 0.000 0.00 32.0 0.00 2 Total Soluble Contaminant Electron Acceptor Demand Flux (Ib/yr)I 0.02 I Initial Hydrogen Demand First Year (Ib) 27.16 Total Life -Cycle Hydrogen Demand (Ib) 118.20 6. Design Factors and Total Hydrogen Demand Microbial Efficiency Uncertainly Factor 2X - 5X Methane and Solid -Phase Electron Acceptor Uncertainty 2X - 5X Remedial Design Safety Factor (e.g., Substrate Leaving Reaction Zone) 1X - 2X SOLUBLE SUBSTRATE DESIGN FACTOR: 1.0 HRC DESIGN FACTOR: 0.0 SLOW RELEASE EDIBLE OIL DESIGN FACTOR: 5.0 Area-, revised.)ds A-15 1/16/2008 TABLE A-2 AREA-4 INJECTION PROTOCOL SWMU-69 FORT BRAGG, NORTH CAROLINA Substrate Molecular Formula(gm/mole) Substrate Molecular Weight Moles of Hydrogen Produced per Mole of Substrate Ratio of Hydrogen Produced to Substrate (gm/gm P&P Manual Appendix C Lactic Acid (assuming 100%) C3H603 90.1 15 0.3357 2 Molasses (assuming 100% sucrose) C121-122011 342 15 0.0883 8 Fructose (assuming 100%) C6H1206 180 8 0.0895 4 Ethanol (assuming 100%) C21-160 46.1 2 0.0875 2 HRC C391-156099 956 24 0.0506 26 Linoleic Acid (Soybean Oil, Corn Oil, Cotton Oil) C161-13202 281 12 0.0862 16 Table A-3 Estimated Substrate Requirements for Hydrogen Demand in Table 1, Area 4 Desian Life (years): 5 Substrate Design Factor Pure Substrate Mass Required to Fulfill Hydrogen Demand (pounds) Substrate Product Required to Fulfill Hydrogen Demand (pounds) Substrate Mass Required to Fulfill Hydrogen Demand (milligrams) Effective Substrate Concentration m /L Lactic Acid 0.0 0 0 0.00E+00 0 Sodium Lactate Product 60 percent solution 1.0 352 587 2.66E+08 20 Molasses(assuming 60% sucrose by weight) 0.0 0 0 0.00E+00 0 Fructose Product(assuming 80% fructose by weight) 0.0 0 0 O.00E+00 0 Ethanol Product(assuming 80% ethanol by weight) 0.0 0 0 0.00E+00 0 HRC® assumes 40% lactic acid and 40% glycerol by weight 0.0 0 0 0.00E+00 0 Linoleic Acid Soybean Oil, Com Oil, Cotton Oil) 0.0 0 0 0.00E+00 0 Commercial Vegetable Oil Emulsion Product 60% oil by weight) 5.0 6,853 11,421 5.18E+09 383 NOTES: Sodium Lactate Product 1. Assumes sodium lactate product is 60 percent sodium lactate by weight. 2. Molecular weight of sodium lactate (CH3-CHOH-COONa) = 112.06. 3. Molecular weight of lactic Acid (C6H603) = 90.08 . 4. Therefore, sodium lactate product yields 48.4 (0.60 x (90.081112.06)) percent by weight lactic acid. Area-4- revised.As A - 16 1/15/2008 } AREA4 INJECTION PROTOCOL SWMU-69 FORT BRAGG, NORTH CAROLINA Well ID Injection Points Substrate Injection Mixture Total Volume Injection Interval (feet) Estimated Effective Porosity (percent) Radius of Influence (reel) Injection Time at 4 gpm (hours) Injection Interval (feet Injection Spacing (feet) Emulsion Product 50% oil by weight) Neat So bean Oil Buffering Agent Makeup .SVater (gallons) Substrate (pounds) Water+ Substrate (gallons) Volume (gallons) Soybean Oil (gallons) (pounds) Lactate (pounds) (allons) (pounds) (gallons) (pounds) SWMU691NJ4-1 16-35 9 35 17.3 134.8 15.4 151 1.174 25 265 3.500 1.324 3.710 19 25% 5.8 15.5 SWMU691N14-2 16-35 9 35 17.3 134.5 15.4 151 1.174 25 265 3.500 1.324 3.710 19 25% 5.8 15.5 SWMU691NJ4-3 16-35 9 35 17.3 134.8 15.4 151 1.174 25 265 3.500 1.324 3.710 19 25% 5.8 15.5 SWMU691N14-4 16-35 9 35 17.3 134.8 15.4 151 1.174 25 265 3.500 1.324 3.710 19 25% 5.8 15.5 SWMU691N14-5 16-35 9 35 17.3 134.8 15.4 151 1.174 25 265 3.500 1.324 3.710 19 25% 5.8 15.5 SWMU691N14-6 16-35 9 35 17.3 134.8 15.4 151 1.174 25 265 3.500 1.324 3,710 19 25% 5.8 15.5 SWMU69IN34-7H16-359E13-50 17.3 134.8 15.4 151 1.174 25 265 3.500 1.324 3.710 19 25% 5.8 15.5 SWMU691NJ4-817.3 134.8 15.4 151 1.174 25 265 3.500 1.324 3.710 19 25% 5.8 15.5 SWMU691N)4-917.3 134.8 15.4 151 1,174 25 265 3,500 1.324 3,710 19 25% 5.8 15.5 §WMU691NJ4-10173 134.8 15.4 151 1.174 25 265 3,500 1.324 3.710 19 25% 5.8 15.5 TOTAL: 173 1�48 154 I,505 11,739 245 2,646 35,000 13.242 37,100 19 Days: 10 SUBSTRATE CONCENTRATIONS Final Percent Substrate by Weight: 4.5% Final Lactic Acid Concentration: 0 S grams/liter Percent Oil by Volume in Emulsion: 4.8 % Final Percent Water by Weight: 95.5 Final Oil Concentration: 42A grams/liter EFFECTIVE TREATMENT ZONE CONCENTRATIONS Design Life (years): 5 Lactic Acid Treatment Zone Concentration (mg/L): 74 Final Vegetable Oil Concentration (rng/L): 440 Treatment Zone Volume+ Groundwater Flux Volume 3,573547 gallons Pereentnce nfTreatment Zone Volume relative to Volume of lniected Fluid' 42A NOTES: Sodium Lactate Product I. Assumes WillClear sodium lactate product is 60 percent sodium lactate by weight. 2. Molecular weight of sodium lactate (CH,-CHOH-COONa) = 112.06. 3. Molecular weight of lactic Acid (Ct1160�) = 90.08. 4. Specific gravity of WillClear Product = 1.323 a 20 degrees Celsius. 5. Weight of WillClear Product = 11.0 pounds per gallon. 6. Pounds per gallon of lactic acid in product= 1.323 x 8.33 lb/gal 40 x 0.60 x (90.08/112.06) = 5.31 lb/gal. .NOTES: Fructose Product I. Assumes fructose product is 80 percent fructose sugar by weight. NOTES: Vegetable Oil Emulsion Product I. Assumes emulsion product is 60 percent soybean oil by weight. 2. Soybean oil is 7.9 pounds per gallon. 3. Assumes sepcific gravity of emulion product is 0.96 and that emulsion product is 4 percent sodium lactate by weight. Drums Gallons Total Totes Gallons Total Emulsion Product Emulsion Product 1 55 6.4 1 220 1.6 Neat Soybean Oil Neat Sovbean Oil 1 55 27.4 1 220 6.8 Sodium Lactate Sodium Lactate I 55 0.0 1 1 220 0.0 Area.4 revised.xls A - 17 1115/200B TABLE A-1 . . AREA'-5 INJECTION PROTOCOL SWAfU-69 FORT, BRAGG, NORTH CAROLINA' 1. Treatment Zone Physical Dimensions Values Range Units. Width (Perpendicular to predominant groundwatef flow direction) " 140 1-10.000 . feet' Length (Parallel to, predominant•groundwater flow) 20 ,1=1,600 :feel Saturated Thickness 9.5 1A00. feet .. TrealmenLZone Cross Sectional Area 1330 - ftZ Treatment Zone Volume 26,600 ft' Treatment Zone Total Pore Volume (total volume x total porosity) 59,706 - :gallons '. Treatment Zone Effective Groundwater, Volume (total volume x effective porosity) 49,755 - gallons Design Period of Performance 51, .5 to 5 year 2. Treatment Zone Hydrogeologic Properties. . . Total Porosity 30% .05-50 . Effective Porosity 25% .05-50. . Average Aquifer Hydraulic Conductivity 18 .01-1000 ft/d;iy. . Average Hydraulic Gradient uoa . '0.1-0.0001 wft Average Groundwater Seepage Velocity through the Treatment Zone 057 '. " - " ft/day, Average Groundwater Seepage Velocity through the Treatment Zone .209.1 -. ft/yr 'Average Groundwater Flux through the Treatment Zone 520,122 - gallons/year . Soil Bulk Density' 1.65 1,4-2.0' ' gm/cm'. ' Soil Fraclion.Orgariic Carbon (foe) 0.0021 0.0001=0.1 1.Initia6Treatment Cell.Electron-Acceptor Demand (one total pore volume)-. A: Aqueous -Phase Native Electron Acceptors Oxygen. avg'of 4 readings Nitrate .Sulfate Carbon Dioxide (estimated as the amount of Methane produced) Concentration (mg .IL) Mass (lb) Sloichiometric, demand : (wt/wt hi) . Hydrogen' Demand : (lb) Electron Equivalents per Mote 5.5 : 2.74 : 7.9 . 0.35 4 1.3 0.65 .10.2 . 0.06, 5 5 _ 2:49. 10.6 0.24- 8 15.0 7.47, 5.5 1:3T 8 ' Soluble Competing Electron Acceptor Demand (lb.) 2;0 . Stoichiometric- Hydrogen Electron B. Solid -Phase N7ative Electron Acceptors Concentration ' Mass demand Demand r Equivalents.per (mg/L) (lb) _ (wt/wt h2) : (lb) Mote• Manganese (IV) (estimated as the amount of Mn (11) produced) 1.0 0.50 27:5 0.02 1 Iron (III) (estimated as the amount of Fe ill) produced) 15 7.47 55.9 0:13 ' 1 Solid -Phase Competing Electron Acceptor Demand (lb.) 0.15 C. Soluble Contaminant Electron Acceptors Telfachlofoelhene (PCE), Trichloroethene (TCE) Dichloroelhene (cis-DCE, trans-DCE, and 1,1-DCE) Vinyl Chloride (VC) Carbon Tetrachloride (CT) Trichloromethane ( or chloroform) (CF) Dichloromelhane (or methylene "chloride) (MC) ' Chloromethane Tetrachloroethane (1,1;1,2-PCA and 1,1,2;2-PCA) Trichloroethane (1,11J-TCA and 1,1,2-TCA) Dichloroelhane (1,1-DCA and 1,2-DCA) Chloroethane Stoichiometric Hydrogen Electron Concentration Mass demand. Demand Equivalents per (mg/L) (lb) (wt/wt h1) (lb) _ Mole. . 0.000 0.00 20.6 0.00 8 0.045 0.02 21.7" D.00 . . '. 6 0.000. 0.00 24.0 0.00 4 0.000 0.00 31.0 0.00.. 2 0.000 : 0.00, .19.1 0:00• " 8 0.000 0.00. 19.8 0.00. _ 6 '. 0.000 0.00 21.1 0.00 . 4. .. 0.000 .' 0.00 - .25.0. 0.00 2 0.000 0.00 20.8 ` 0.00 8. '. . 0.000 - 0,00 22.1 0.00 6 0.000 0.00 24.5 0.00 4. 0.000 0.00 32.0 0.00 2 . Total Soluble Contaminant Electron Acceptor Demand (lb.) 0.00.. D; Sorbed Contaminant Electron Acceptors (Soil. Concentration = Koc x foc x Cgw) Telrachloroelhene (PCE). Trichloroethene (TCE) Dichloroethene (cis-DCE, trans-DCE,:and 1;1-DCE): Vinyl Chloride (VC) Carbon Tetrachloride (CT) Trichloromethane ( or chloroform) (CF) Dichloromethane (or methylene chloride) (MC) Chloromethane Tetra chloroethane.(1,1,1,2-PCA and 1,1,2,2-PCA) Trichloroetharie (1,1,1-TCA and 1,1,2-TCA) Dichloroethane (1,1-DCA end 1,2-DCA) Chloioethane Stoichiometric Hydrogen. Electron Koc Soil Conc., - -Massa demand 'Demand,-. Equivalents per (mUg) (mg/kg).. (lb) (vAW h2): (lb) , : .. '. Mole . 263 0.00 0.00. 20.6 0.00. 8 107 0.01 .0.03 21.7 0.00 . 6 45: 0.00 0.00. .24.0 0.00. 4 3.0 0.00 0.00 .31;0 '. '0.00 . 2 224 0.00 0.00 25.4 0.00 8' 63 0.00 0.00 12.3 -0.00 6 - 28 -0.00 0.00 21.1 0.00 '. 4 25 0.00 0.00 25.0 0.00 2 117 0.00 0.00 " 20.8 0.00 8' 105 0.00 0.00 22.0 0:00 '. 6. 30 0.00 0.00 .25.0 0.00. 4 3 0.00 : 0.00 32.0 0.00 : 2 4. Treatment Cell Electron -Acceptor Flux (per year) A. Soluble Native Electron Acceptors TABLE A-1 Concentration (mg/L) Mass (lb) Stoichiometric demand (wthvl hz) Hydrogen Demand (lb) Electron Equivalents per Mole 5.5 23.87 7.9 3.02 4 0.3 1.43 10.2 0.14 5 5 21.70 10.6 2.06 8 15 65.10 5.5 11.92 8 Oxygen Nitrate Sulfate Carbon Dioxide (estimated as the amount of Methane produced) Total Competing Electron Acceptor Demand Flux (Ib/yr) 17.1 B. Soluble Contaminant Electron Acceptors Tetrachloroethene (PCE) Trichloroethene (TCE) Dichloroethene (cis-DCE, trans-DCE, and 1,1-DCE) Vinyl Chloride (VC) Carbon Tetrachloride (CT) Trichlorom ethane ( or chloroform) (CF) Dichloromethane (or methylene chloride) (MC) Chloromethane Tetrachloroethane (1,1,1,2-PCA and 1,1,2,2-PCA) Trichloroethane (1,1,1-TCA and 1,1,2-TCA) Dichloroethane (1,1-DCA and 1,2-DCA) Chloroethane Stoichiometric Hydrogen Electron Concentration Mass demand Demand Equivalents per (mg/L) (lb) (wUwt hz) (lb) Mole 0.000 0.00 20.6 0.00 8 0.045 0.20 21.7 0.01 6 0.000 0.00. 24.0 0.00 4 0.000 0.00 31.0 0.00 2 0.000 0.00 19.1 0.00 a 0.000 0.00 19.8 0.00 6 0.000 0.00 21.1 0.00 4 0.000 0.00 1 25.0 0.00 2 0.000 0.00 20.8 0.00 8 0.000 0.00 22.1 0.00 6 0.000 0.00 24.5 1 0.00 4 0.000 0.00 32.0 1 0.00 2 Total Soluble Contaminant Electron Acceptor Demand Flux (lb/yr)l 0.01 I Initial Hydrogen Demand First Year (lb) 19.32 Total Life -Cycle Hydrogen Demand (Ib) 0*20 5. Design Factors and Total Hydrogen Demand Microbial Efficiency Uncertainty Factor 2X - 5X Methane and Solid -Phase Electron Acceptor Uncertainty 2X - 5X Remedial Design Safety Factor (e.g., Substrate Leaving Reaction Zone) 1X - 2X SOLUBLE SUBSTRATE DESIGN FACTOR: 1.0 HRC DESIGN FACTOR: 0.0 SLOW RELEASE EDIBLE OIL DESIGN FACTOR: 5.0 kea 5.& A - 19 1/15/2008 TABLE A-2 AREA-5 INJECTION PROTOCOL SWMU-69 FORT BRAGG. NORTH CAROLINA Substrate Molecular Formula Substrate Molecular Weight m/mole Moles of Hydrogen Produced per Mole of Substrate Ratio of Hydrogen Produced to Substrate (gm/gm P&P Manual Appendix C Lactic Acid (assuming 100%) C3H603 90.1 15 0.3357 2 Molasses (assuming 100% sucrose) C121-122011 342 15 0.0883 8 Fructose (assuming 100%) C61-11206 180 8 0.0895 4 Ethanol (assuming 100%) C2H60 46.1 2 0.0875 2 HRC C391-156039 956 24 0.0506 26 Linoleic Acid (Soybean Oil, Corn Oil, Cotton Oil) C181-13202 281 12 0.0862 16 Table A-3 Estimated Substrate Requirements for Hydrogen Demand in Table 1, Area 5 Design Life (vears): 4.9 Substrate Design Factor Pure Substrate Mass Required to Fulfill Hydrogen Demand (pounds) Substrate Product Required to Fulfill Hydrogen Demand (pounds) Substrate Mass Required to Fulfill Hydrogen Demand (milligrams) Effective Substrate Concentration m /L Lactic Acid 0.0 0 0 0.00E+00 0 Sodium Lactate Product 60 percent solution 1.0 257 428 1.94E+08 20 Molasses(assuming 60% sucrose by weight) 0.0 0 0 0.00E+00 0 Fructose Product(assuming 80% fructose by weight) 0.0 0 0 0.00E+00 0 Ethanol Product(assuming 80% ethanol by weight) 0.0 0 0 0.00E+00 0 HRC® assumes 40% lactic acid and 40% glycerol by weight) 0.0 0 0 0.00E+00 0 Linoleic Acid (Soybean Oil, Corn Oil, Cotton Oil 0.0 0 0 O.00E+00 0 Commercial Vegetable Oil Emulsion Product 60% oil by weight) 5.0 4,997 8,329 3.78E+09 383 NOTES: Sodium Lactate Product 1. Assumes sodium lactate product is 60 percent sodium lactate by weight. 2. Molecular weight of sodium lactate (CH3-CHOH-COONa) = 112.06. 3. Molecular weight of lactic Acid (CGH603) = 90.08 . 4. Therefore, sodium lactate product yields 48.4 (0.60 x (90.08/112.06)) percent by weight lactic acid. Ar",4iYls A ' 20 1/15/2008 J AREA-5 INJECTION PROTOCOL SWMIJ-69 FORT URAGG, NORTH CAROLINA In-ection Points "Substrate Injection Mixture. Total Volume Estimated Injection Injection Injection Emulsion Product (50 % oil by weight) - _ Buffering, Mdkeup. - _ Water + Injection Effective .Radifis.or Time Well "Interval- Spacing .Volume-' Soybean Oil . ' Lactate_ -Neat Sov'bean Oil Aent .-Water Substrate .Substrate .Interval 'Porosity. "Influence, at4gpm ' ID (feet). (feet)(gallons) .(gallons) (pounds) (pounds) '(gallons) 1-( omds) (gallons) ( ounds) (gallons). (no unds) (gallons) (feet)' (percent) (feet) :(hours) SWMU69 INJ5-1 31-�10 ., 9:..' ..- 14 ..6.9. .53.9 '. 6.2 74 - 379 10 106 1,400- - 639" "1,498 9 -2i% - '5.3 "-6.2 . . SWMU69iN)5-2 31.40-. 9 .. 14 6.9 539, 6.2 74 579 - IU .106 1.400 639 IA98. -" .9. 25%. 5.-3 .. 6.2" SWMU69 M.15-3. - 31-40 9 14 . 6.9 53.9. 6.2- 74 . 579 10 .' 106 1.400 ' .639 ,I WS 1 9 . - 25'S'u - 33, fi 2 SWMU691N15.4 31G0 9' ."14 6.9. '53.9 .6.2 74 579 ' . In 166 .1.400 639. " . 1.49M . 9' 25% --'5.3 "- 6 SWMU691N15-5 3140 -. "9, " 14 . - . .6.9 ' S3.9. 6.2 74- " 579 . 1(1 . 106 1.400, 639 - 1.498 - " 9 25% 53 " 6.2 SWMU691N15-6 -.3140 -Y. 14 6.9 S3J'- . f.2 -"74. 579 10 ,I(Ifi .IA(IIl f+39 •1.498 -9 -25%' 5.3 6.2. SWMU691N15-7 31-I0- 9 14 6.9.. 53.9' 6.2 74 ' 579 10 IUfi 1.400 .- 639 1A98 9 23%. 33 6? SWMU69IN15-8 3140. _ � 9 : .14 . " 6.9 .. 53.9 61 74 " � i79 - 10 166 I A60 639 ' ' L'498 9 25% " 5. 6.2 SWMU691NJ5-9 .31-10 " 9 . .14 " 6.9 53.9 .6.2 74 . 579 M .• 106 1.400 - 639 - 1.498 9, .25% . 5.3 6.2 SWMU69.1NJ5-10 "3146.' '"'-.9 14 -' 6.9 53.9- 6.2. - 74 579' M 106 1.460 ,639 -.1.498 9 .25% 5.3 62' SWMU691NJ5=I1 31-40 - 9. -' .14 - 6.9- 53.9 6.2 74. - 579. M I06 1.400. 639 ". 1.498 '-9. .25% 5.3 :'6.2- SWMU69IN15-12 31-40: 9 14 .6.9 .53.9 6.2' 74 .. 579 1(1 1116 Intl0 639. "IA98 .Y 25% 5.3, ,. .62', TOTAL: ' .168 83 647 74. . 890" 6,945. :1I8 1,270 16,900 - 7.666 " 17,976 9 Do si S SUBSTRATE CONCENTRATIONS- - - Final Percent Substrate by Weight:. '5.5 % Final Lactic Acid Concentration: 0.5 gramslliler. Percent Oil by Volume in Emulsion: 5.8 . Find Percent Water by Weight: 94.5./ " _ Final Oil Concentration:. 50.7 " granis/liter EFFECTIVE TREATMENT ZONE CONCENTRATIONS . Design Life.(years): 4.9 . - "Lactic Acid Treatment Zone Concentration (mg/L): 49: Final Vegetable Oil Concentration (mg/L):.. S56 . . Treatment Zone Volume+Groundwater Flux.VolLiriie" '2,608.304 ,gallons Percentage of Treatment Zone Volume relative to Volume of rijecied Fluid . .' 36.1% NOTES::Sodium Lactate Product - - - 1. Assumes WillClearsodium lactate,product is 60.perccni sodium lactate by weight. - 2. Molcculanvciglit of sodium lactate (CH-CHOH-COONa) .= 112.06. - 3. Molecularsicight of lactic Acid (C6H60�)=90:08 - . J. Specific gm6it.• of.WillClear Product = 1,3234a; 20 degrees Celsius. 5: Weight ofWillClcar Product II.Opounds per gallon. ,G. Pounds per gallonof lactic acid inproduci =' 1.323 x 8.33,lb/gal W x 0.60 x (90.08/1 12.06) = 5.31 lb/gal; NOTES; Fructose Product Drums Gallons Total Totes. . 'Gallons Total Emulsion Product. Emulsion Product , Ncat Soybean Oil' :Neat Soybcun Oil - - -'1 55 162- .. 1 -"220 4.0 Sodium Lactate Sodium Lactate '_ . I . 33 0.0. ': "1 '' 220 '' .0.0 1. Assures fmctosc pmduet is,80 percent fructose sugar by %wight. NOTES: Vegetable Oil Emulsion Product - - 1. Assumes emulsion product is'60 percent soybean oil by s4eight: 2. Soybean oil 1s 7:8. pounds pei gallon.. - - - - - - 3. Assumes- se cific g vity of emulion product is 0.96 and that emulsion product is 4 percent sodium lactate by weight. - APPENDIX B it UNDER GROUND INJECTION PERMIT APPLICATION S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMIP\final\Final Fort Bragg SWMU69 CMIP.doc State of North Carolina -� Department of Environment and Natural Resources Division of Water Quality Non -Discharge Permit Application Form (THIS FORM MAYBE PHOTOCOPIED FOR USE AS AN ORIGINAL) GROUNDWATER REMEDIATION SYSTEMS This permit application form is for systems which use either infiltration galleries or injection wells to discharge treated groundwater into the subsurface. Each section of this application must be completed unless otherwise noted. Contact the Aquifer Protection Section at (919) 733-3221 to obtain Groundwater Remediation Permit Application Guidelines. I. GENERAL INFORMATION: 1 Applicant's name (please specify the name of the municipality, corporation, individual, etc.): Fort Braes Department of Public Works 2 Print Owner's or Signing Official's name and title (the person who is legally responsible for the facility and its compliance): Mr. Greg Bean 3 Mailing address: Directorate of Public Works, ATTN: IMSE-BRG-PWE-C (Jason Adcock), BLDG: 3-1137 Butner Road City: FORT BRAGG State: NC Zip:28310 1 Telephone Number: ( 914) 432-8450 4 Project Name (please specify the name of the facility or establishment - should be consistent,on all documents included in this application package: Fort Brags Solid Waste Management Unit 69 5 Mailing address: Same as above (item 3) City: State: Zip: Telephone Number: ( ) 6 County of Remediation Activities: Cumberland Latitude: 35 deg 9' 22.7" ; Longitude 78 deg 59' 1.13" of Remediation Activities. 7 Contact person who can answer questions about application: Name: Dan Griffiths (Parsons Corporation) Telephone Number: ( 303 ) 764-1940 8 Application Date: Janua 11'h 2007 9 Fee Submitted: $ 0.00 (Refer to fee schedule at http://h2o.enr.state.nc.us/aps/gpu/NDgwRemedy.htm ) II. PERMIT INFORMATION: Application No. (will be completed by DWQ): 1. Specify whether project is: X new; renewal; modification *For renewals, complete only sections I, II, and applicant signature (on page 8). Submit only pages 1, 2, and 8 (original and three copies of each). Engineer's signature not required for renewal without other modifications. 2. If this application is being submitted as a result of a renewal or modification to an existing permit, list the existing permit number FORM: GWRS 02/06 Page 1 of 11 and its issue date III. INFORMATION ON CONTAMINATED GROUNDWATER: I List the principal products or services provided by facility: Arm, Facility for military personnel training, housing, and equipment maintenance and storage. 2 Remediation Site Owner: X Federal;_ State;_ Private; _Public; _Native American Lands; Other (specify) 3 Groundwater Incident Number (if known): none 4 Is this application for facilities subject to UST Trust Fund reimbursement? Yes; X No. 5 Has a comprehensive site assessment and corrective action plan been submitted and approved for this project? X Yes; No. Please provide two copies of each and two copies of the approval letter (if applicable). 6 Provide a brief description of the events or cause of the groundwater contamination: Historic vehicle storage and dismantlement activities resulted in contaminant releases to the ground surface. Contaminants migrated vertically to eventually impact site groundwater. Surface water criteria exceedances have not been documented at SWMU 69 to date (Parsons, 2007). List contaminants detected: PCE, TCE, 1,1,2,2-TeCA (Parsons, 2007) Volume of groundwater to be remediated per day: Approximately 77,367 gallons (per day) 9 Explanation of how volume was determined: The cross sectional area of the intended treatment areal (6,930 square feet) (Parsons, 2008) was multiplied by the effective soil porosity (25%) (Parsons 2007) multiplied by the average site hydraulic conductivity (5.97 ft/day) (Parsons, 2007) and converted to gallons of water (7.48 gallons/cubic foot) This calculation is given by Darcy's Law. IV. GENERAL DESIGN INFORMATION: 1. Specify the type of system that is being installed: infiltration gallery; X injection well(s); other (specify): 2. Provide a brief description of all components of the treatment and disposal system (i.e., treatment units, pumps, tanks, chemical feed system, injection and/or recovery wells, etc.): Potable water will be supplied to the injection system from a nearby fire hydrant by running a high density polyethylene (HDPE) line from the fire hydrant to a large storage tank. The storage tank will be filled periodically during injection and the full tank will serve as the water supply during injection. A second HDPE line will be run from the bottom valve on the storage tank to the substrate blending and mixing system. The organic substrates (soybean oil, soy lecithin, sodium lactate, and a food -grade pH amendment product will then be amended into the hydrant water at the correct dosage rate inline through a series of dosimeters. A static high sheer in -line mixer will be used to emulsify the soybean oil -lecithin mixture ani'_, potable water to form an oil -in -water emulsion. This oil -in -water emulsion will then be pumped to each injection area with FORM: GWRS 02/06 Page 2 of 11 an air operated diaphragm pump through HDPE conveyance lines. Within each injection area site groundwater will be extracted from existing groundwater monitoring wells for re -injection with the oil -in -water emulsion being piped from the substrate mixing area. Submersible pumps will be temporarily installed in one or two monitoring wells (depending on the injection area) to supply site water for injection. The discharge lines from the submersible pumps will be tied in to the supply line coming from the mixing system through a manifold consisting of valves and.flow meters designed to measure flow from the groundwater extraction pumps and flow coming from the mixing system. The mixtures of site groundwater and hydrant water will be different for each injection area and will depend on the rate at which groundwater can be extracted from the formation. The mixture of potable water, substrate, and site groundwater will then be injected into the subsurface through direct push rods and temporary injection wells. 3. 15A NCAC 2C .0213 (Well Construction Standards, Applicable to Injection Wells) requires that contaminant levels in the fluid injected into any well be monitored; therefore, a sampling port must be provided on the effluent lines (treated water prior to being injected into the wells or infiltration gallery). The permit will specify the requirements for monitoring this effluent. Identify the location in the plans/specifications where the sampling port design is detailed: Refer to Figure 3.5 in the attached corrective measures implementation plan V. DESIGN INFORMATION FOR INFILTRATION GALLERIES: 1. Specify the dimensions of each infiltration gallery: (a) L= ft. W= ft. D= ft. (b) L= ft. W= ft. D= ft. (c) L= ft. W= ft. D= ft. 2. The static groundwater level at the gallery location is feet. The vertical separation between the gallery trench bottom and the mean seasonal high water table is feet. 3. A North Carolina licensed soil scientist must provide an evaluation of the soils where the infiltration gallery will be located and must specify an acceptable loading rate (amount of water gallery can accept). This evaluation should determine whether - the loading rate shall be based upon only the surface area of the infiltration gallery or whpthpr if'is appropriate to include some of the side wall depth. a. What is the area used to determine the loading rate? square feet. This area should include only the surface area. No side wall depth should be included in this calculation. b. The recommended loading rate is (Attach all calculations). c. Indicate the theory behind the loading rate determination: 4. Briefly describe any mounding of groundwater, above the static groundwater levels, that may result from infiltration (Attach calculations and/or diagrams): VI. DESIGN INFORMATION FOR INJECTION WELLS: 1 Identify the principal aquifer to which the injection wells will be discharging: Middendorf Aquifer J4) 2 Is the aquifer identified above the same aquifer from which the contaminated groundwater was extracted? FORM: GWRS 02/06 Page 3 of 11 3 X Yes No. If No, describe how the aquifers are hydraulically related: Briefly describe any mounding of groundwater, above the static groundwater levels, that may result from the injection (please. - attach calculations and/or diagrams): Significant long term mounding is not expected because of the short injection duration (less than 24 hours at any one point) and the low planned iniection rate with respect to groundwater flow rates. The fluid erection rate at each point is unlikely to exceed 10 gpm while the natural groundwater migration rate at this site is approximately 1 2 feet per day. Thus groundwater mounding will be minimal during iniection and will disperse immediately after injection is complete. 4 Characteristics of injection well(s) [attach additional sheets if necessary]: Injection Well Characteristics Well A (Temporary PVC well) (Total of 30points)point) Well B (steel direct push total of 32points) Well C Depth (feet) 35-45 35-45 Diameter (inches) 1" 0.75" Injection rate (GPM) <10 gpm <10 gpm Injection volume (GPD) <3,200 <3,200 Injection pressure (PSI) <40 psi <40 psi Injection temp. (°C) Ambient ground surface temperature Ambient ground surface temperature Casing material PVC Steel Depth of casing (feet) 15-35 15-35 Casing diameter (inches) 1" 0.75" Casing schedule number 40 NA Cement grout (primary or inner casing) (feet below ground surface) from _0_ ft. to 10 ft. from NA ft. to NA ft. from ft. to ft. Cement grout (outer casing, if applicable) from NA ft. to ft. from _NA ft. to NA ft. from ft. to ft. Screened or uncased interval (if applicable) from 15 ft. to 45 ft. from 15 ft. to 45 ft. from ft. to ft. Type of screen manufactured or hand slotted if applica.ble manufactured Manufactured Screens inner diameter (inches -if applicable) 1" 0.75" Gravel pack (if applicable) from NA ft. to ft. from NA ft. to ft. from ft. to ft. Well contractor TBD TBD Contractor Registration No. TBD TBD FORM: GWRS 02/06 Page 4 of 11 VII. ADDITIONAL INFORMATION: 1 Classification of the closest downslope surface waters: (as established by the Environmental Management Commission and specified on page 7 of this application). The nearest downslope surface water body is Young Lake (approximately 1 mile downslope) In accordance with 15A NCAC 2H .0219 0) (3), describe which measure is being utilized to prevent overflows into downslope surface waters or adjacent aquifers in the event of a power failure or equipment malfunction. The substrate injection system will be monitored at all times by Parsons personnel. Shutoff valves will be located at both ends of the system that can be closed immediately upon the detection of a leak or line break (as indicated by pressure gauges installed at both ends of the system). The system will be driven by air operated diaphragm pumps. The pumps are equipped with check valves and will not allow water to pass through them if they are shutdown. Thus, if power or air pressure is lost than the injection system will shutdown and no injection fluid will be lost. Refer to Figures 3.4 and 3.5 of the attached corrective measures implementation plan for injection system schematics. The applicable buffers should be met in accordance with 15A NCAC 2H .0200 and 15A NCAC 2H .0400. Some of those buffers are described below: a. 100 feet between injection wells or infiltration galleries and any private or public water supply source; b. 50 feet between injection wells and waters classified as WS, B, or other streams, canals, marshes, lakes, impoundments, or coastal waters; c. 100 feet between infiltration galleries and waters classified as WS, B, or other streams, canals, marshes, lakes, j impoundments, or other coastal waters; d. 100 feet between injection wells or infiltration galleries and the mean high water of waters -classified as SA or SB; e. 100 feet from injection well and infiltration gallery treatment and disposal systems dlid`the normal high water of Class I and Class 11 impounded reservoirs which are used as a source of drinking water; f. 50 feet from injection well and infiltration gallery treatment and disposal systems and property lines. If any of the applicable buffers cannot be met, please explain how the proposed buffers will provide equal or better protection of the surface or groundwaters with no increased potential for nuisance conditions: All prescribed buffer requirements will be met. 4. Substances may be added to enhance in situ treatment. If microbial additives or cultures are added in the effluent, the approval must be provided by the North Carolina Division of Epidemiology certifying its use for remediation purposes. In lieu of the Division of Epidemiology approval, risk assessment data, toxicological exposure data, or approval from another State may be provided certifying an exposure risks. Will any substances be added to the effluent to enhance in situ treatment? X Yes; No. If Yes, provide a detailed description of these substances, including amounts to be added. In addition, please attach any studies which describes the instances in which these substances have been used: The bioaugmentation culture product KB-1 (manufactured by Sirem Laboratories Inc.) will be added'to the injection water and substrates to promote in -situ degradation. KB-1 will be added at a rate of 0.25 liters per injection well (total of 8 liters) at SWMU-69. The product KB-1 (Sirem Laboratories) has already been accepted by NCDENR for use -in North Carolina FORM: GYMS 02/06 Page 5 of 11 THIS APPLICATION PACKAGE WILL NOT BE ACCEPTED BY THE DIVISION OF WATER QUALITY UNLESS ALL OF THE APPLICABLE ITEMS ARE INCLUDED WITH THE SUBMITTAL a. One original and two copies of the completed and appropriately executed application form. b. The appropriate permit processing fee in accordance with 15A NCAC 2H .0205(c)(5). c. Submit three copies of the Corrective Action Plan and comprehensive site assessment. These Documents are enclosed. d. Three copies of the existing permit if a renewal or modification. This requirement is not applicable because this is an application for a new permit. Three sets of detailed plans and specifications signed and sealed by a North Carolina Professional Engineer. The plans must include a general location map; a topographic map which extends one mile beyond property boundaries and depicts the facility and each of its intake and discharge structures (with the quadrangle name); a scaled site -specific map which indicates where borings or hand auger samples were taken; and a map showing the, groundwater treatment/disposal facilities, buffers, structures and property lines. A map must also identify any hazardous waste treatment, storage, and disposal facilities; each well where fluids from the facility are injected underground; and those wells, springs and other surface water bodies and drinking water wells listed in public records or otherwise known to the applicant within a quarter mile of the facility property boundary. Each sheet of the plans, including any plan pages that are incorporated into a bound document, and the first page of the specifications, must be signed/sealed by a North Carolina Professional Engineer. This information can be found in the enclosed Final Corrective Measures Implementation Plan. f. Three copies of a tabulation of data on all wells which are within the area of review and which penetrate the proposed injection zone. Such data shall include an identification number (same number referenced on map required in "e" above) for each well, a description of each well type, date installed, depth of well, and record of completion or abandonment (if available). This information can be found in the enclosed Final Corrective Measures Study. g. A soil scientist report which includes texture, color, and structure of the soils down to a depth of seven feet; depth, thickness and type of any restrictive horizons, hydraulic conductivity in the most restrictive horizon, Cation Exchange Capacity, depth of the mean seasonal high water table, soil pH, soil maps (if available, even if unpublished), and recommended loading rates (when using an infiltration gallery). This report must be signed by the soil scientist. A description of site soils is presented in the enclosed Final Corrective Measures Study. h. A hydrogeologic description, soils description, and cross section of the subsurface to a depth that includes the known or projected depth of contamination. The number of borings shall be sufficient to determine significant changes in lithology, the vertical permeability of the unsaturated zone, the hydraulic conductivity of the saturated zone, the depth to the mean seasonal high water table, and a determination of transmissivity and specific yield of the unconfined aquifer (show calculations used for transmissivity and specific yield). Report should also indicate whether the aquifer is attributable to fracture porosity storage or stratigraphically controlled (bedding planes). Include a general map and cross section illustrating the regional geologic setting. This information can be found in the enclosed Final Corrective Measures Study. i. Describe the proposed injection procedure and describe expected changes in pressure and direction of movement of injected fluid (provide data from fracture studies where applicable). Applicant must demonstrate complete hydraulic control over contaminant plume and injectate if injectate does not meet 2L standards. The injection procedure including expected injection flow rates and pressures can be found in Section 3 of the enclosed Final Corrective Measures Implementation Plan. The injection fluid may not meet 2L standards because a portion of the injection fluid will consist of untreated groundwater extracted from the injection area. Therefore, modeling calculations were performed to determine if the injected fluid is likely to cause significant plume expansion into previously uncontaminated areas. These calculations are presented on Attachment one to this Groundwater Remediation Permit Application. j. Proposal for groundwater monitoring (e.g., schedule, analytical methods, etc.). This information can be found in the enclosed Final Corrective Measures Implementation Plan. k. Describe the method for determining mechanical integrity of injection well over a five year period. The injection wells are temporary and will be used for a maximum of three separate, short duration injections. Each injection episode will not exceed approximately 24 hours in length. Thus, a determination of long term injection well mechanical integrity is not necessary and does not apply. I. A complete analysis of the contaminated -groundwater to include, but not limited to BTEX, volatile and semivolatile compounds, pH, nitrates, and phosphates or any additional information the Director deems necessary to evaluate the proposed treatment and disposal system. This information can be found in the enclosed Final Corrective Measures Study. in. Describe contaminant concentrations in the effluent given the proposed treatment. Include expected treatment efficiency. Provide calculations or documentation to show how proposed degree of treatment was derived. The proposed treatment will take place in -situ and will employ the injected organic substrates. Large volumes of treated water will not be re -injected as in the case of a typical pump and treat system. Thus, this request does not apply. However, it is our intent to re -inject FORM: GWRS 02/06 Page 6 of 11 untreated site groundwater with the afore mentioned organic substrates as well as potable water from an approved source. Thus, the injection fluid will likely contain low concentrations of contaminants present in site groundwater including TCE, 1,1,2,2-TeCA, and PCE. Concentrations of these compounds in the injection fluid will not exceed concentrations in site groundwater and will in fact be j considerably lower because the site groundwater in the injection fluid will be diluted with potable water and the organic substrates. --/ However, PCE, TCE, and 1,1,2,2-TeCA concentrations in the injection fluid may exceed NC 2L standards. n. Diagram, of the contaminant plume both horizontally and vertically, including vadose zone contamination (isoconcentration maps and plume cross sections). Include direction of groundwater flow for both surface aquifer and deep aquifers. This information can be found in the enclosed Final Corrective Measures Study. o. Three copies of all reports, evaluations, agreements, supporting calculations, etc., must be submitted as a part of the supporting documents which are signed and sealed by the North Carolina Professional Engineer. Although certain portions of this required submittal must be developed by other professionals, inclusion of these materials under the signature and seal of a NC PE signifies that he or she has reviewed this material and has judged it to be consistent with his or her proposed design. Three copies of the Final Corrective Measures Study and the Final Corrective Measures Implementation Plan are enclosed. p. An properly executed page 7, which has been completed by the appropriate Regional Aquifer Protection personnel, and reincorporated into the application form prior to submittal of the application package. FORM: GWRS 02/06 Page 7 of 11 This form must be completed by the appropriate DWQ regional office and included as a part of the project submittal information. INSTRUCTIONS TO APPLICANT In order to determine the classification of the watershed in which the subject facility will be located, you are required to submit this form, with items 1 through 7 completed, to the appropriate Division of Water Quality Regional Aquifer Protection Supervisor (see attached listing) prior to submittal of the application for permitting. At a minimum, you must include an 8.5" by I I" copy of the portion of a 7.5 minute USGS Topographic Map which shows the subject surface waters. You must identify the location of the facility and the closest downslope surface waters (waters for which you are requesting the classification) on the submitted map copy. The application may not be submitted for final permitting until this form is completed by the appropriate regional office and included with the submittal. Applicant (please specify the name of the municipality, corporation, individual, or other): Fort Bragg Department of Public Works Mailing address: BLDG: 3-1137, Butner Road City: Fort Bragg_ State: North Carolina Zip:28310 Telephone Number: ( 910 ) 432-8450 County(ies) where the facility is located: Cumberland 4. Project Name: Fort Bragg Solid Waste Management Unit 69 - 5. Name of closest surface waters: Young Lake 6. Map name and date: Manchester Quadrangle; 1997 7. Applicant Signature: TO: REGIONAL AQUIFER PROTECTION SUPERVISOR Please provide me with the classification of the watershed and appropriate river basin where these activities will occur, as identified on the attached map segment: Name of surface waters: Classification (as established by the EMC): Proposed Classification, if applicable: River Basin the Facility is Located: Signature of regional office personnel: FORM: GWRS 02/06 Page 8 of 11 Date: Name and Complete Address of Engineering Firm: Parsons Corporation 1700 Broadway, Suite 900 City: Denver State: CO Zip:80290 Telephone Number: ( 303 ) 764-1940 Fax Number: ( 303 ) 831-8208 Professional Geologist's Certification: attest that this application for has been reviewed by me and is accurate and complete to the best of my knowledge. I further attest that to the best of my knowledge the proposed design has been prepared in accordance with the applicable regulations. Although certain portions of this submittal package may have been developed by other professionals, inclusion of these materials under my signature and seal signifies that I have reviewed this material and have judged it to be consistent with the proposed design. North Carolina Professional Geologist's Seal, Signature, and Date: Applicant's Certification (signing authority must be in compliance with 15A NCAC 2H .0206(b)): I, attest that this application for has been reviewed by me and is accurate and complete to the best of my knowledge. I understand that if all required parts of this application are not completed and that if all required supporting information and attachments are not included, this application package will be returned to me as incomplete. Signature Date THE COMPLETED APPLICATION PACKAGE, INCLUDING ALL SUPPORTING INFORMATION AND IVIATERIALS, SHOULD BE SENT TO THE FOLLOWING ADDRESS: FORM: GWRS 02/06 NORTH CAROLINA DIVISION OF WATER QUALITY AQUIFER PROTECTION SECTION GROUNDWATER PROTECTION UNIT 1636 MAIL SERVICE CENTER RALEIGH, NORTH CAROLINA 27699-1636 TELEPHONE NUMBER: (919) 733-3221 FAX NUMBER: (919) 715-0588 Page 9 of 11 DIVISION OF WATER QUALITY REGIONAL OFFICES Asheville Regional APS Supervisor 2090 U.S. Highway 70 Swannanoa, NC 28778 (828)296-4500 Fax (828) 299-7043 Avery Macon Buncombe Madison Burke McDowell Caldwell Mitchell Cherokee Polk Clay Rutherford Graham Swain Haywood Transylvania Henderson Yancey Jackson Fayetteville Regional APS Supervisor Systel Building, Suite 714 Fayetteville, NC 28301 (910)486-1541 Fax (910) 486-0707 Washington Regional APS Supervisor 943 Washington Square Mall Washington, NC 27889 (252)946-6481 Fax (252) 946-9215 Beaufort Jones Bertie Lenoir Camden Martin Chowan Pamlico Craven Pasquotank Currituck Perquimans Dare Pitt Gates Tyrell Greene Washington Hertford Wayne Hyde Mooresville Regional APS Supervisor 610 East Center Ave., Suite 301 Mooresville, NC 28115 (704)663-1699 Fax (704) 663-6040 Raleigh Regional APS Supervisor 3800 Barrett Drive, Suite 101 Raleigh, NC 27609 (919)791-4200 Fax (919) 571-4718 Chatham Nash Durham Northampton Edgecombe Orange Franklin Person Granville Vance Halifax Wake Johnston Warren Lee Wilson Wilmington Regional APS Supervisor 127 Cardinal Drive Extension Wilmington, NC 28405-3845 (910)796-7215 Fax (910) 350-2004 Anson Moore Alexander Lincoln Brunswick New Hanover Bladen Robeson Cabarrus Mecklenburg Carteret Onslow Cumberland Richmond Catawba Rowan Columbus Pender Harnett Sampson Cleveland Stanly Duplin Hoke Scotland Gaston Union Montgomery Iredell Winston-Salem Regional APS Supervisor 585 Waughtown Street Winston-Salem, NC 27107 (910)771-4600 Fax (910) 771-4630 Alamance Rockingham Alleghany Randolph Ashe Stokes Caswell Surry Davidson Watauga Davie Wilkes Forsyth Yadkin Guilford FORM: GWRS 02/06 Page 10 of 11 l Fort Bragg SWMU 69 Groundwater Remediation Permit Application - Attachment 1 Plume Expansion Calculations The volume of groundwater present in the SWMU 69 groundwater plume, as defined by the TCE 1.0 µg/L contour can be calculated by multiplying volume of the plume by the effective porosity of the aquifer matrix and converting the resultant volume in cubic feet to gallons. This calculation is completed below. Area of the SWMU 69 TCE plume: 36 acres (Parsons, 2007) or 1,742,000 square feet. The contaminated thickness averages approximately 15 feet (Parsons, 2007). The total volume of the SWMU 69 TCE plume = 26,130,000 cubic feet (1,742,000 square feet X 15 feet). The volume of groundwater in the SWMU 69 plume is = 58,636,000 gallons (26,130,000 cubic feet X the effective porosity of 30% (Parsons, 2007) X 7.48 gallons per cubic foot). The maximum volume of fluid that will be injected at SWMU69 is approximately 172,000 gallons (including the contingency second substrate injection and the contingency bioaugmentation injection [refer to section 3 of Parsons, 20081). The volume of injection fluid is conservative because a portion of this injection fluid will consist of site groundwater and is thus not "new fluid" that will be added. However, the site groundwater to be reinjected is included in the calculation in order to make this plume expansion estimate more conservative. The total maximum volume of injection fluid represents 0.293 percent of the total volume of water within the SWMU 69 TCE plume. Thus the maximum plume expansion that may occur due to the proposed injection activities is approximately 1.09 feet (the square root of 1,742,000 square feet X 1.00293 divided by rl). FORM: GWRS 02/06 Page 11 of 11 SECTION 1 INTRODUCTION In 1988, the State of North Carolina Department of Environmental Health and Natural Resources (NCDENR), in conjunction with the United States Environmental Protection Agency (USEPA) Region 4, issued a Hazardous Waste Facility Permit to Fort Bragg. The Former Jeep Dismantling Area was identified in the permit as Solid Waste Management Unit (SWMU) 69. SWMU 69 was listed as requiring a Resources Conservation and Recovery Act (RCRA) Facility Investigation (RFI) based on the findings of the 1988 Fort Bragg RCRA Facility Assessment (RFA) conducted by Kearney, Inc and DPRA, INC (Kearney and DPRA; 1988) in accordance with RCRA. The United States Geological Survey (USGS) conducted an RFI of SWMU 69 from 1994 to 1998. The results of the RFI were presented in the April 1999 USGS report entitled: RCRA Facility Investigation at Operable Unit 4, Fort Bragg Installation Restoration Program, Fort Bragg, North Carolina, Volume I (USGS, 1999). Operable Unit 4 is a designation of the Installation Restoration Program (IRP) and consists of SWMU 69, SWMU 63, and Areas of Concern (AOC) E, F,- and G. The RFI concluded that various volatile organic compounds (VOCs) identified during that investigation have migrated, through the soils into the groundwater>witliin and around the area of SWMU 69. Based on the results of the RFI investigation, NCDENR and Fort Bragg Directorate of Public Works (DPW) determined that a supplemental RFI was warranted. Work supporting the supplemental RFI was performed in 2001 and 2002. Results of the initial investigation revealed the presence of chlorinated solvents, pesticides and petroleum related compounds in the soils and groundwater at SWMU 69. The Supplemental RFI delineated the Chemicals of Potential Concern (COPCs) in the soils in the suspected source area and concluded that the soils did not contain significant levels of COPCs above the screening criteria and; therefore, do not pose a continuing source of contamination to the groundwater at SWMU 69. It also concluded that the areas of detected concentrations of VOCs in the groundwater were' the result of either the co - mingled plumes of several small releases over a widespread area or of multiple releases at SWMU 69 over a period of years. A supplemental monitoring event was conducted in 2004 to delineate the concentrations of VOCs in the groundwater in the area downgrad'ient, of SWMU 69. Groundwater samples were collected from existing selected monitoring wells as well as from additional downgradient locations. 1.1 PURPOSE AND ORGANIZATION OF REPORT Parsons Infrastructure and Technology Group, Inc. (hereafter referred to as Parsons) prepared this report for the Army Environmental Command (AEC) under contract number W91ZLK-05-D-0016, task order 0001. This report presents the Corrective i 1-1 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS,doc Measures Study for SWMU 69 following the Office of Solid Waste and Emergency , Response (OSWER) Directive 9902.3- 2A dated May 1994 "RCRA Corrective Action ; Plan". The purpose of the report is to identify and evaluate alternatives for remedial action and to provide a recommended plan of corrective action for the site. The report is divided into 11 sections and two appendices for presentation of the pertinent data and remedial action alternatives. • Section 1 presents the introduction and provides the purpose and organization of this report. • Section 2 provides background information on regulatory issues and previous investigations/actions conducted at the site. • Section 3 covers the environmental (physical) setting at the site and Fort Bragg in general. • Section 4 discusses previous investigations and the nature and extent of contamination. • Section 5 provides a summary of the site conceptual model, baseline risk assessment, and impacts to human health and the ecological environment. • Section 6 provides justification for corrective measures :at SWMU 69 and identifies corrective measures objectives proposed to mitigate existing and future threats to human health and the environment. • Section 7 identifies available remediation technologies for potential application at SWMU 69. • Section 8 presents a selection of remedial technologies that could be applied at SWMU 69. • Section 9 evaluates and develops corrective measures alternatives from the remedial technologies presented in Section 8 to determine the most effective technology. • Section 10 presents a comparative analysis of the remedial alternatives and presents a conceptual design for a selected remedial alternative. • Section 11 provides various references used in the preparation of the -report. • Appendix A contains selected historic data drawn from the SWMU 69 RI report and the CSM report. • Appendix B contains tables to support the Human Health Risk Assessment. • Appendix C contains performance data from other enhanced bioremediation applications. • Appendix D contains contaminant trend charts for each monitoring well at SWMU 69. 1-2 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\final\Final SWMU69 CMS.doc Corrective Measures Study for SWMU 69 Jeep Dismantling- Area Fort Bragg, North Carolina Submitted To: J.S. ARMY ENVIRONMENTAL COMMAND L Submitted By: RECERIFED JUN 112008 May 2007 Doi R�FAYE-Ti cVI��EREGi0f4ALQF�I(;E 17 May 2007 Ms. Bridget Lyons US. Army Environmental Command, IMAE-CDS/Bridgett Lyons " 5179 Hoadley Road, Bldg E-4480 APGEA, MD 21010-5401 Subject: Submittal of the Final Corrective Measures Study — SWMU 69 Jeep Disinantlirig Area, 'Fort Bragg; North Carolina (USAEC Contract W91ZLK-050D-0016; Task Order 0001) Ms. Lyons, Please find enclosed one . hard copy and. two electronic copies of the Final Corrective-:'. Measures Study - SWMU 69 Jeep Dismantling Area, Fort Bragg, North Carolina.. This final document was,prep.ared by Parsons. Infrastructure, &'Technology Group, Inc. (Parsons) for the - United -States Army Environmental Command.(USAEC)..Copies, of this final document were. also submitted to Ms: Barbara Hebert at the Fort. Bragg installation for installation Use Additional copieswere submitted to Ms.. Hebert for -.subsequent distribution to the North..,. Carolina Department of Natural Resources. (NCDENR) and USAC&Savannah. If you have any questions or require additional information, please contact'me at (901) 572-5999 or at ross.miller@parsoiis.com. Sincerely, PARSONS Ross Miller PhD, .PE Project Manager cc: Ms.:Barbara:Hebert' : Fort Bragg (5 :copies) Ms. Angie Cook — Parsons Atlanta (l. copy) ':Mr:. Dan Griffiths = Parsons Denver (1 copy) Final SWM069 CMS cover letter.doc 'EXECUTIVE SUMMARY A corrective measures study. (CMS) was prepared for. the. former Jeep. Dismantling Area,. Solid Waste Management Unit (SWMU) 69 at the Fort Bragg Military Reservation, North Carolina, to evaluate potential corrective actions for addressing contaminants in groundwater. This . report has been prepared by Parsons Infrastructure and Technology Group; Inc. (hereafter referred .to as Parsons)- for .the Army Environmental Command under contract number W9 1 ZLK-050D-00 16, task order 0001. SWMU 69 is located southeast of the intersection of Woodruff and Knox Streets, and occupies an area of approximately 3 to 4 acres. The site :is :fenced, with most of the area covered by asphalt or gravel. SWMU 69 was historically used as an area where jeeps were dismantled and is currently used for the storage of .military vehicles and other supplies.. A Resource Conservation and Recovery Act (RCRA). facility investigation (RFI) was conducted from 1994 through 1999 'to determine the nature and extent of contamination and to develop the, site conceptual model (SCM) for SWMU.: 69. The RFI concluded that a CMS was required for SWMU 69 and supplemental investigations and. bench -scale and in -situ pilot studigs were required: A supplemental RFI was performed in 2001-2002 and included: 1. the collection .of 78 soil samples from 24 soil borings drilled within the suspected source area., t 2. the collection of groundwater samples from the 28 existingmonitoring wells, 3. the installation of 22 temporary piezometers in the areanorth of SWMU 69 (in the vicinity of the electrical substation and the twounnamed tributaries to Young Lake) to improve the definition and understanding of the groundwater potentiometric .surface, 4. the .collection of 81, groundwater grab samples using direct .push , drilling methods. to update the vertical and horizontal delineation of the nature and extent of groundwater contamination. A second roundof. supplemental RFI activities were conducted .in -2004 which included collecting :groundwater samples from 10 existing groundwater monitoring wells, the collection, of three surface :water samples from previously sampled locations, and. the collection of additional groundwater grab samples using:diiect.push drilling methods. A third round of supplemental RFI activities were conducted, in 2006: which included the collection of three. surface water samples from the unnamed tributaries to Young Lake. A fourth round of groundwater samples were collected under this contract in February 2007. The, supplemental data collected between 2001 and 2007 did not change the conclusions of the. RFI or SCM for SWMU 69. Low concentrations of chlorinated solvents are present in: groundwater :originating from 'SWMU :69. No remaining soil source was identified at SWMU 09, but a series of 5 hot spots have been identified with groundwater data collected from monitoring wells and as grab samples collected with direct push drilling methods.. One hot spot is located in the. SWMU' 69. area while the remaining four are located downgradient of SWMU 69. Tetrachloroethene . (PCE) and ES-1 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc This alternative would require a long-term monitoring program as well as the establishment and maintenance of ICs to prevent exposure to contaminants through groundwater use. -1 Alternative 2: Institutional Controls and In Situ Organic Substrate Addition in 5 Treatment Areas • Institutional controls to prevent the. use of groundwater. • Enhanced bioremediation using anaerobic reductive dechlorination to destroy contaminant mass in 5 large areas encompassing the majority of the currently defined SWMU 69 plume. • MNA for remaining groundwater contamination. • Groundwater and surface water monitoring to evaluate performance. The active portion of the remedial alternative would treat groundwater using enhanced bioremediation (i.e., anaerobic reductive dechlorination) in 5 large treatment areas, to reduce chlorinated solvent concentrations in treatment zone groundwater. NINA would be used to further reduce the remaining groundwater contaminants to meet the North Carolina 2L standards. Alternative 3: Institutional Controls and In Situ Organic Substrate Addition - Hot Spots Only • Institutional controls to prevent the use of groundwater. • Enhanced bioremediation using anaerobic reductive dechlorination to destroy contaminant mass in 5 relatively small hot spots encompassing a small portion of currently defined SWMU 69 plume. • MNA for remaining groundwater contamination. • Groundwater and surface water monitoring to evaluate performance. The active portion of the remedial alternative would treat groundwater using enhanced bioremediation (i.e., anaerobic reductive dechlorination) in 5 relatively small hot spot areas where contaminant concentrations are the highest, to reduce chlorinated solvent concentrations in treatment zone groundwater. MNA would be used to further reduce the remaining groundwater contaminants to meet the North Carolina 2L standards. Alternative 4: Institutional Controls with In Situ Chemical Oxidation Using Sodium Permanganate in 5 Treatment Areas • Institutional controls to prevent the use of groundwater. • In -situ chemical oxidation (ISCO) using sodium permanganate to destroy contaminant mass in 5 large areas encompassing the majority of the currently defined SWMU 69 plume. • MNA for remaining groundwater contamination. • Groundwater and surface water monitoring to evaluate performance. The active portion of the remedial alternative would'treat groundwater using ISCO in 5 large treatment areas, to reduce chlorinated solvent concentrations in treatment zone groundwater. The 5 treatment areas would be same as those presented in alternative 2. ES-3 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc remain in the subsurface to treat contaminant mass that diffuses out of the soil matrix. Whereas ISCO provides reactant mass to the subsurface that lasts only a short period of time, resulting in the potential for COC concentration rebound. In addition, alternative 3 is superior to alternative 5 in terms of cost. Alternative 3 is approximately $164,000 cheaper than alternative 5. Thus, alternative 3 is the preferred alternative for groundwater remediation at SWMU 69. The total time to implement Alternative, 3 is estimated to be approximately 20 years. The total capital cost for Alternative 3 is $493,860. The operation and maintenance costs are $413,000. The total cost of Alternative 3 is $906,860. ES-5 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc TABLE OF CONTENTS Page _ EXECUTIVESUMMARY...........................................................................................ES-1 LIST OF ACRONYMS AND ABBREVIATIONS.......................................................... iv SECTION 1 - INTRODUCTION ............ :::.................................................................. 1-1 1.1 Purpose and Organization of Report ....................................................................1-1 SECTION 2 - SWMU 69 SITE BACKGROUND.......................................................... 2-1 2.1 Site Background................................................................................................... 2-1 2.1.1 Location and Site Description.................................................................. 2-1 2.1.2 SWMU 69 Site History............................................................................ 2-3 SECTION 3 - SWMU 69 ENVIRONMENTAL SETTING.............................................3-1 3.1 Physiography and Topography............................................................................ 3-1 3.2 Climate:................................................................................................................3-1 3.3 Geology and Hydrogeology................................................................................. 3-2 3.4 Groundwater Hydrology...................................................................................... 3-3 3.5 Surface Water Hydrology.................................................................................... 3-4 3.6 Potable Water Supply.......................................................................................... 3-7 r , SECTION 4 - PREVIOUS INVESTIGATIONS AT SWMU 69.................................... 4-1 4.1 USGS RFI 1994-1999..........................................................................................4-1 4.2 Supplemental RFI (USACE) 2001-2002............................................................. 4-2 4.2.1 Surface and Subsurface Soil.................................................................... 4-2 4.2.2 Groundwater............................................................................................ 4-3 4.3 2004 Sampling Event........................................................................................... 4-4 4.4 2007 Groundwater Sampling Event...................................................................... 4-9 4.5 Surface Water and Sediment................................................................................ 4-9 4.6 HRC Pilot application results............................................................................. 4-10 SECTION 5 - SITE CONCEPTUAL MODEL............................................................... 5-1 5.1 SWMU 69 Site Conceptual Model...................................................................... 5-1 5.2 Natural Attenuation Evaluation for COCs in Groundwater ................................. 5-2 5.3 Human Health Risk Evaluation........................................................................... 5-5 5.3.1 Uncertainties............................................................................................ 5-5 5.4 Remedial Goal Options........................................................................................ 5-6 SECTION 6 - JUSTIFICATION AND IDENTIFICATION OF CORRECTIVE ACTION ALTERNATIVES ........................................ 6-1 6.1 Corrective Measures Objectives.......................................................................... 6-1 6.2 Identification of Remedial Levels........................................................................ 6-2 -i- S:\ES\Itemed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doe TABLE OF CONTENTS (Continued) Page 10.2 Summary of Analysis of Corrective Action Alternatives..................................10-7 10.3 Conceptual Design of Selected Alternative.......................................................10-7 10.3.1 Establishment of Institutional Controls.................................................10-8 10.3.2 Complete Groundwater Network........................................................... 10-9 10.3.3 Enhanced Bioremediation 1h Hot Spot Areas........................................10-9 10.3.4 Monitored Natural Attenuation..............................................................10-9 10.3.5 Monitoring...........................................................................................10-10 10.3.5.1 Groundwater........................................................................10-10 10.3.6 Investigation -Derived Waste............................................................... 10-10 10.3.7 Operation and Maintenance................................................................. 10-12 10.3.8 Reporting..............................................................................................10-12 10.3.8.1 Corrective Action Completion Report ................................10-12 10.3.8.2 Periodic Progress Reports...................................................10-12 10.3.8.3 Periodic Remedy Reviews..................................................10-12 10.3.9 Monitoring Well Abandonment...........................................................10-12 10.4 Cost Estimate....................................................................................................10-12 10.5 Implementation Schedule.................................................................................10-12 SECTION 11 - REFERENCES.....................................................................................11-1 APPENDICES A - Selected Historic Data B - Human Health Risk Assessment Tables C - Supporting Performance Data D - Contaminant of Concern Concentration Trends S:\ES\Remed\745446 Fort'Bragg PB020010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc LIST OF ACRONYMS AND ABREVIATIONS 1,1,2,2-TeCA 1,1,2,2-tetrachloroethane AEC Atomic Energy Commission AFB Air Force Base AOC Areas of -Concern ARAR applicable or relevant,and appropriate requirements bgs below ground surface BMP Base Master Plan BTEX benzene, ethyl benzene, toluene, and xylenes CAH chlorinated aliphatic hydrocarbons cis-1,2-DCE cis-1,2-dichloroethene CMS Corrective Measures Study COC chemical of concern COPC chemical of potential concern COPC contaminant of potential concern CSF cancer slope factors CSM conceptual site model DNAPL dense non -aqueous phase liquid DO dissolved oxygen DPW Department of Public Works ELCR excess lifetime cancer risk EPC Exposure point concentrations FID flame ionization detector ft feet ft/day feet per day '- ft/ft feet per foot ft/year feet per year ft square feet g/cm3 grams per cubic centimeter HI hazard index HQ hazard quotient HRC® Hydrogen Releasing Compound ILCR incremental lifetime cancer risk IRP Installation Restoration Program ISCO in -situ chemical oxidation lb/ft pounds per foot lbs pounds LTM long-term monitoring LUC land use controls MCL maximum contaminant level MDC maximum detected concentrations mg/L milligrams per liter µg/kg micrograms per kilogram MNA monitored natural attenuation Mn02 manganese oxide mph miles per hour msl mean seal level f -v- SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc SECTION 1 INTRODUCTION In 1988, the State of North Carolina Department of Environmental Health and Natural Resources (NCDENR), in conjunction with the United States Environmental Protection Agency (USEPA) Region 4, issued a Hazardous Waste Facility Permit to Fort Bragg. The Former Jeep Dismantling Area was identified in the permit as Solid Waste Management Unit (SWIVIU) 69: SWMU 69 was listed as requiring a Resources Conservation and Recovery Act (RCRA) Facility Investigation (RFI) based on the findings of the 1988 Fort Bragg RCRA Facility Assessment (RFA) conducted by Kearney, Inc and DPRA, INC (Kearney and DPRA; 1988) in accordance with RCRA. The United States Geological Survey (USGS) conducted an RFI of SWMU 69 from 1994 to 1998. The results of the RFI were presented in the April 1999 USGS report entitled: RCRA Facility Investigation at Operable Unit 4, Fort Bragg Installation Restoration Program, Fort Bragg, North Carolina, Volume I (USGS, 1999). Operable Unit 4 is a designation of the Installation Restoration Program (IRP) and consists of SWMU 69, SWMU 63, and Areas of Concern (AOC) E, F. and G. The RFI concluded that various volatile organic compounds (VOCs) identified during that investigation have migrated through the soils into the groundwater:uvitlin and around the area of SWMU 69. Based on the results of the RFI investigation, NCDENR and Fort Bragg Directorate of Public Works (DPW) determined that a supplemental RFI was warranted. Work supporting the supplemental RFI was performed in 2001 and 2002. Results of the initial investigation revealed the presence of chlorinated solvents, pesticides and petroleum related compounds in the soils and groundwater at SWMU 69. The Supplemental RFI delineated the Chemicals of Potential Concern (COPCs) in the soils in the suspected source area and concluded that the soils did not contain significant levels of COPCs above the screening criteria and; therefore, do not pose a continuing source of contamination to the groundwater at SWMU 69. It also concluded that the areas of detected concentrations of VOCs in the groundwater were the result of either the co - mingled plumes of several small releases over a widespread area or of multiple releases at SWMU 69 over a period of years. A supplemental monitoring event was conducted in 2004 to delineate the concentrations of VOCs in the groundwater in the area downgradient� of SWMU 69. Groundwater samples were collected from existing selected monitoring wells as well as from additional downgradient locations. 1.1 PURPOSE AND ORGANIZATION OF REPORT Parsons Infrastructure and Technology Group, Inc. (hereafter referred to as Parsons) prepared this report for the Army Environmental Command (AEC) under contract number W91ZLK-05-D-0016, task order 0001. This report presents the Corrective - 1-1 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc Measures Study for SWMU 69 following the Office of Solid Waste and Emergency Response (OSWER) Directive 9902.3- 2A dated May 1994 "RCRA Corrective Action Plan". The purpose of the report is to identify and evaluate alternatives for remedial action and to provide a recommended plan of corrective action for the site. The report is divided into 11 sections and two appendices for presentation of the pertinent data and remedial action alternatives. • Section 1 presents the introduction and provides the purpose and organization of this report. • Section 2 provides background information on regulatory issues and previous investigations/actions conducted at the site. • Section 3 covers the environmental (physical) setting at the site and Fort Bragg in general. • Section 4 discusses previous investigations and the nature and extent of contamination. • Section 5 provides a summary of the site conceptual model, baseline risk assessment, and impacts to human health and the ecological environment. • Section 6 provides justification for corrective measures at SWMU 69 and identifies corrective measures objectives proposed to mitigate existing and future threats to human health and the environment. • Section 7 identifies available remediation technologies for potential application at SWMU 69. • Section 8 presents a selection of remedial technologies that could be applied at SWMU 69. • Section 9 evaluates and develops corrective measures alternatives from the remedial technologies presented in Section 8 to determine the most effective technology. • Section 10 presents a comparative analysis of the remedial alternatives and presents a conceptual design for a selected remedial alternative. • Section 11 provides various references used in the preparation of the report. • Appendix A contains selected historic data drawn from the SWMU 69 RI report and the CSM report. • Appendix B contains tables to support the Human Health Risk Assessment. • Appendix C contains performance data from other enhanced bioremediation applications. • Appendix D contains contaminant trend charts for each monitoring well at SWMU 69. 1-2 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\final\Final SWMU69 CMS.doc SECTION 2 SWMU 69 SITE $ACKGROUND The RFA of potential Fort Bragg solid/hazardous waste sites was conducted in 1988 by A.T. Kearney, Inc and provided an assessment of actions required by Fort Bragg under RCRA, including actions for the Former Jeep Dismantling Area. Subsequently, the NCDENR and the USEPA Region 4 issued a Hazardous Waste Storage Permit, which identified SWMU 69 (former Jeep Dismantling Area) as requiring a RFI. 2.1 SITE BACKGROUND 2.1.1 Location and Site Description SWMU 69 is located southeast of the intersection of Woodruff and Knox Streets, and occupies an area. -of approximately 3 to 4 acres. The site is fenced, with most of the site area covered by asphalt or gravel. SWMU 69 is currently used for the storage of military vehicles and other supplies. Figure 2.1 shows the location of SWMU 69 within Fort Bragg and provides a map of the immediate area of SWMU 69 and the surrounding buildings. The majority of property use near SWMU 69 consists of administrative offices, support facilities, and warehouses. A CP&L power substation is located to the north and along the eastern. boundary of the site. Major power transmission lines run north to south adjacent to the`east side of the power substation. SWMU 69 is bordered on the south and west by railroad tracks. The Central Issuing Facility is located south of the railroad tracks in buildings 8-3710 and 8-3502. Several buildings are located along the northern portion of SWMU 69. These include: 8-4608, a weapons maintenance building; 8-4807, a Retiree Services Office; and 8-4813, the Space Activity Office. Firearms were cleaned at the weapons maintenance building (USGS, 1999), and two drums labeled "dry-cleaning solvent" were observed stored outside of this building during a 1997 site visit. Two additional SWMUs (AOC E and SWMU 71) are located along the northern fence line of SWMU 69. AOC E is a fuel -stained area associated with a 500-gallon heating oil underground storage tank (UST) that is located south of building 8-4806 and north of SWMU 69. The UST has been removed and the area has been investigated under the North Carolina UST program. AOC E was given no further action status (NFA) by the NCDENR UST section on September 2, 1999 and by the NCDENR Superfund section on September 26, 2000. 2-1 SA.ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc MR FA t • DOUyOaR �.✓ � ln� IPA m i f T r ��r ��• :f,F�o 4xuV '�' a nn� Pn�"'}?+' aU MER Rn GLv- Pa r p �a lu8gend F2btI �:.'-1 Building -- - hail :Road BVVMij Area 8irebm order . Fort Bragg ` Lake i~ i PopeAF8 Source; USACE,.2006; dravA745446 SWMU 69 Locatlon Pdap:cdr na . 5/07107 SWMU 71 was identified in the 1988 RFA (see section 2.0) as an inactive site and as having a low potential for a past release to have occurred. As a result of the RFA, SWMU 71 was listed in the Fort Bragg RCRA Part "B" Permit in Table II. Table II is a list of all SWMUs at Fort Bragg with no known releases and; therefore, require no further action. SWMU 71 consists of two small storage buildings (8-4513 and 8-4613). Previously these buildings were used as a 90-day hazardous waste storage area. Fifty-five gallon drums of 1, 1, 1 -trichloroethane, 1,1,2,2-tetrachloroethane (1,1,2,2-TeCA) methanol, paint wastes, decontamination agent, and a carbon -removing compound were documented to have been stored in this area (USGS, 1999). Storage of hazardous wastes was discontinued at SWMU 71 in 1984. Currently, this site is used for storage by an electrical contractor. 2.1.2 . SWMU 69 Site History Jeeps and other equipment were dismantled during the years 1988 to 1990. Before the dismantling activities, this area had been used for vehicle parking and storage since the 1970's. A visual site inspection conducted during the 1988 RFA indicated that oil had leaked from old motors onto the unprotected ground. Stacks of vehicle parts were observed scattered over the ground surface. 2-3 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\final\Final SWMU69 CMS.doc This page intentionally left blank SECTION 3 SWMU 69 ENVIRONMENTAL SETTING 3.1 PHYSIOGRAPHY AND TOPOGRAPHY Fort Bragg occupies parts of two counties of North Carolina, northwestern Cumberland County and northern Hoke County. According to the 2000 US Census, Cumberland County encompasses a 661 square mile area and has a population of 302,000. Hoke County covers about 414 square miles and has a population of 43,000, (US Census Bureau, 2000). The principal industries of Cumberland County are textile manufacturing and timber production. Hoke County's major industry is agriculture; mainly tobacco, cotton, corn, and other grains. Fort Bragg has a combined military and civilian population of approximately 29,000. The principal pipulation centers near Fort Bragg are the city of Fayetteville (population 121,000), located 5 miles to the southeast, and Spring Lake (population 8,100), which is located adjacent the eastern boundary of Fort Bragg. Fort Bragg is located in the Sand Hills hydrologic area of the North Carolina Coastal t` Plain in southeastern North Carolina. The Sand Hills area is characterized by deep sandy soil and has the most variable topography and highest land -surface elevation in the Coastal Plains. Topography at Fort Bragg is characterized by gently=to steeply sloping ridges, most of which are located in the central and western sections of the installation. Elevations at Fort Bragg range from 550 feet (ft) above mean sea level (msl) in the west to 150 feet in the northeast, adjacent to the Little River. The topography of the actual SWMU 69 site is flat with an elevation of about 293 feet above msL The area north of SWMU 69 was included in the.expanded investigation•and varies in elevation from 293 feet above msl to 225 feet. Ground surface in this area slopes downward in a northerly direction toward Young's Lake and its tributary. Relief is greatest adjacent to this tributary. Figure 2.1 shows the location of SWMU 69 and the surrounding area. 3.2 CLIMATE The climate in this part of North Carolina is classified as subtropical, characterized by long hot summers and mild winters. From 1951 to 1980, the mean annual precipitation was 47.80 inches. From 1984 to 1993, the mean annual precipitation at Pope,Air Force Base (AFB) was 46.62 inches. The mean monthly precipitation rates from 1984 to 1993 are shown iri Table 3.1. Relative humidity ranged from a monthly average of 63 percent in April to 76 percent in August. The mean annual temperature was 62.4 degrees, and the prevailing wind direction is from the southwest with an average velocity of approximately 9 miles per hour (mph). SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc Table 3.1 Mean Monthly Precipitation at Pope Air Force Base,1984-1993 Fort Bragg, North Carolina January Feb. March April May June- July August Sept. October Nov. December 3.70' 3.28 4.03 3.80 3.84 4.75 5.78 5.71 2.50 3.29 3.55 2.39 " Mean monthly precipitation unit of measure is inches. Intense rainstorms primarily occur during the summer months. Rainfall intensity frequency curves, based on the National Weather Service data for Fayetteville, NC, indicate that 4-inches of rainfall within 2 hours represents a 25-year occurrence interval; 5-inches of rainfall within 2 hours represents a 100-year occurrence interval. 3.3 GEOLOGY AND HYDROGEOLOGY Most of the soil types in the Fort Bragg cantonment area range from moderately well drained to excessively well drained soils in the highly dissected uplands and have brittle loamy or clayey subsoil. These soils are the weathered by-products of the unconsolidated sandy sediments of the Coastal Plain. Soils located in the upland areas are generally sandy, acidic, and low in organic matter and fertility. Soils in the lower elevations are heavier in texture, contain more organic and clay material, and are poorly drained and swampy when adjacent to natural waterways. Because much of the soils often have similar properties, the transition zones are not always apparent. Several soil types are present within the immediate vicinity of SWMU 69 ranging from loamy sand to sandy clay. The major geologic formations in the Fort Bragg area (from oldest to youngest) are the Carolina Slate Belt, the Cape Fear Formation, and the . Middendorf Formation. The Carolina Slate Belt is composed of metavolcanic, metasedimentary, and igneous rocks of Precambrian to Cambrian age. In the area of Fort Bragg, the Carolina Slate Belt is the basement unit and is described as gray -green chlorite schist. In some areas, these rocks were exposed to weathering at the ground surface before being covered by overlying sediments. This weathered area created a zone of porous saprolite at the top of the basement rocks. Where present, this saprolitic zone is described as sandy, gray clay with some green and red clay. The top of the Carolina Slate Belt is about 60 feet above msl near the western edge of Fort Bragg (approximately 230 -feet below ground surface [bgs]). The Cape Fear and Middendorf Formations are of Late Cretaceous age and are part of the Atlantic Coastal Plain deposits. The deposits are sediments that were deposited on top of the basement rocks and generally become thicker and dip toward the southeast. The Cape Fear and Middendorf Formations are non -marine in origin and are generally considered representative of deltaic deposits. In the Sand Hill area of North Carolina, these formations appear to have been deposited in an upper delta -plain environment. The Cape Fear Formation is continuous throughout Fort Bragg. It is overlain directly by the Middendorf Formation, except along the Little River and some of its tributaries, where the Middendorf Formation has been eroded away. The Cape Fear Formation consists of pale -to -medium gray clays and sandy clays with some sand units. The lower 3-2 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc part of the Cape Fear contains beds of greenish -gray clays, some of which have red mottling. The Cape Fear Formation contains more. clay, and the individual quartz -sand beds are generally thinner and finer -grained than in the Middendorf Formation. The top of the Cape Fear Formation is 210 feet above msl in the area of SWMU 69 (approximately 80 feet bgs), and is about: 150 feet thick. The uppermost part of the Cape Fear Formation consists of clay and sandy clay ranging in thickness from 10 to 15 feet. The Middendorf Formation overlies the Cape Fear Formation, and is exposed at the ground surface throughout Fort Bragg. The Middendorf Formation is composed of tan, cross -bedded, medium and fine- grained micaceous quartz sand and clayey sand interbedded with clay or sandy -clay lenses of limited extent. The basal unit of the Middendorf Formation within Fort Bragg is described as a sand layer with rounded quartzite pebbles in a clay matrix at several intervals. Layers of hematite -cemented sandstone occur locally throughout the Middendorf Formation as do thin layers of kaolin and kaolin -cemented sandstone. In summary, the units of the Middendorf Formation have overall higher sand content than the more clayey strata of the Cape Fear Formation. The basal Middendorf sand unit is generally coarser grained and more transmissive than the sand layers of the Upper Middendorf. The upper unit of the Cape Fear Formation consists of a 5- to 10= foot thick clay and sandy clay layer that likely acts as an aquitard, representing a barrier to vertical contaminant migration by advection. 3.4 GROUNDWATER HYDROLOGY The same three geologic formations that underlie Fort Bragg also form the three fresh- water aquifers in this area. The saprolite-basement rock aquifer is composed of the saprolite underlying the Cape Fear Formation and the fracture zones in the uppermost part of the metamorphic and crystalline Cambrian and Precambrian basement rock. This saprolite-basement aquifer is generally assumed to yield little water, and there are no water supply wells known to tap solely into this aquifer. The Cape Fear aquifer is composed primarily of clays interbedded with silt and silty sands in the Fort Bragg area. The uppermost unit (5 to 10 feet) of the Cape Fear Formation is a compact, thick clay unit that serves as an aquitard which restricts the vertical movement of groundwater between the overlying sediments and the silty -sand units of the Cape Fear Formation, creating confined aquifer conditions for the groundwater found in the Cape Fear units below. There are no potable water supply wells in the Fort Bragg cantonment area that tap into the Cape Fear Formation; however, east of Fort Bragg, the Cape Fear aquifer is used for both public and industrial water supply. The major water -bearing aquifer in the Fort Bragg area is the Middendorf aquifer, which consists primarily of coarse -to -fine-grained silty or clayey sands with interbedded light -gray to tan clay. Groundwater in the Middendorf aquifer is commonly under unconfined conditions. In some areas of Fort Bragg, a laterally extensive clay layer is present that separates the Middendorf aquifer into two water -bearing zones. The groundwater in the Upper Middendorf remains unconfined, whereas the groundwater in the lower zone is under confined or semi -confined conditions. The sandy soils of Fort Bragg are highly permeable leached beds of the Upper Middendorf Formation that allow a rapid infiltration of precipitation. Precipitation is the primary source of groundwater recharge for the Middendorf Formation. — ` 3-3 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\final\Final SWMU69 CMS.doc Within the Upper Middendorf, the interbedded and discontinuous clay layers create zones of perched water above the water table. Perched water zones are commonly found within 20 feet of the ground surface. These zones typically contain only a few feet of sediment saturated with water, and many dry out during the summer. In the area of SWMU 69, groundwater is located 38 to 40 feet bgs. The direction of groundwater flow is to the north-northeast, following the general slope of the ground surface and the direction of surface=water drainage (Figure 3.1). Horizontal hydraulic conductivities were determined from slug tests conducted during the RFI (USGS, 1999) at nine of the wells at SWMU 69. Hydraulic conductivities for the Upper Middendorf ranged from 0.9 to 1-3 feet per ' day (ft/day), while the Lower Middendorf ranged from 14 to 78 ft/day. Table 3.2 below presents the wells tested and the hydraulic conductivity determined. Using an average horizontal conductivity of 20 ft/day, an average porosity of 30 percent, and horizontal hydraulic gradients of 0.002 to 0.028 feet per foot (ft/ft), the USGS (1999) calculated the average -linear groundwater velocity to range from 0.16 to 2.24 ft/day (58 to 818 feet per year [ft/yr]). The hydraulic conductivities determined from the wells completed in the Lower Middendorf formation were higher overall than those from the wells completed in the Upper Middendorf. Table 3.2 Summary of Horizontal Hydraulic Conductivity Data at SWMU 69 Fort Bragg, North Carolina Well Identification Hydraulic Conductivity (ft/day) 69MW3 2. 69MW6 13 69MW7 UM 8 69MW 11 0.9 69MW 15D M 17 69MW 161) LM 24 69MW18D LM 78 69MW20D LM 27 69MW21D. LM 14 " UM: Upper Middendorf bl LM: Lower Middendorf 3.5 SURFACE WATER HYDROLOGY An east, -west trending ridge divides Fort Bragg into two drainage sub -basins. Surface water` m the northern subbasin drains into tributaries of the Little River, while the surface water in the southern subbasin drains into tributaries of Cross Creek and Rockfish Creek. Streambeds generally consist of unconsolidated materials; typically silts, sands, and clays. Several impoundments are present at Fort Bragg and include Young Lake in the northern portion of the cantonment area, Lake McArthur in the northwestern corner of the installation, Mackellar's'Pond in the northeastern part of the installation, and Smith Lake in the southeastern section. 3-4 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\final\Final SWMU69 CMS.doc 2 3X r WES z8 _, i ;d, yq Wtl N iL /z4 ". - , 1 r tT7 to 6" 250 6�,m Vul; 4 IV r T F E 200' 0 209 409 r_nj — LEGEND SCALE IN FEET North I j FIGURE 3.1 69MW-1 MONITORING WELL WITH SWMU ® 69 (252) WATER. LEVEL ELEVATIONS Al GROUNDWATER POTENTIOMET J AREA OF GROUND -WATER mbNITOO SURFACE MAP PIEZOMETER. Corrective Measures Study Fort Bragg, North Carolina GROUND -WATER CONTOUR LINES PARSONS - Source: USACE1.2006. - (April 2003):. Denver, Colorado. draW17451446 SlfVM U 69 Surface Mab.cdr ma Si06107 6cl 3 r There are no surface water bodies within the area defined as SWMU 69 other than �. drainage ditches constructed to drain parking areas. However, there are two streams that originate immediately north and northeast of SWMU 69 (Figure 2.1) that may be impacted by contaminants originating from SWMU 69. The streams are unnamed but have been termed collectively as the Young Lake Tributary in USGS (1999). The two streams merge immediately south of Butner road and flow north-northeast toward Young Lake, located approximately 6,000 feet down stream from SWMU 69. 3.6 POTABLE WATER SUPPLY Potable water supplies for Fort Bragg and the surrounding area are obtained from surface water. Water used for drinking water purposes at Fort Bragg is obtained from the Little River, approximately three miles to the north. Water is impounded by two dams located near the Fort Bragg water treatment plant. Two supplemental water supply reservoirs, Lake McArthur and McKellers Pond with a combined capacity of 12.2 billion gallons, are also maintained by Fort Bragg. The city of Fayetteville obtains its water supply from the Cape Fear River and impoundments on Cross Creek and Little Cross Creek. In the past, the City of Spring Lake obtained approximately 25 percent of its water supply from the city of Fayetteville, with the remaining water supplied from a series of five municipal water supply wells. Four of these wells are completed within the Cape Fear Formation, and one is completed within the Middendorf Formation. This well is located approximately 1 mile northeast of SWMU 69; the remaining four wells are located north of this well, about 2 miles north of SWMU 69. Currently, however, the City of Spring Lake purchases 100% of its water supply from Fayetteville. The Fort Bragg Installation has 25 water -supply wells located within. its boundary (Table 3.3). Well depths range from 62 to 600 feet bgs; well yields range from 5 to 170 gallons per minute. Eight of these wells are located in the cantonment area and seven are used to irrigate golf courses. The remaining wells are outside the cantonment area and -are used for various needs other than drinking water. 3-7 S:\ES\Remed\745446 Fort Bragg PBO20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc TABLE 3.3 INVENTORY OF WATER SUPPLY WELLS SWNW69 FORT BRAGG, NORTH CAROLINA Well . Depth to Well yield Well diameter Well depth water (gallons per Number Well Location (inches) (ft bgs) (ft bgs) minute) Comments 1 Ranger Station # 1 6.0 110 60 50 Potable water well 2 Ranger Station #2 6.0 65.5 42 60 Potable water well 3 Ranger Station #3 6.0 90.5 55.5 60 Potable water well 4 Ranger Station Headquarters 6.0 337 85 NA b� Not in service 5 Aberdeen Radar Site near King Road NA NA NA 60 Potable water well 6 Sensor Test Area north of Manchester Road on Longstreet Road. 4.0 70.0 NA 18 Not in service 7 Recondo Camp on Manchester Road 6.0 96.0 NA 28 Potable water well 8 Ammunition Dump 8.0 62.0 NA 30 Potable water well 9 Ammunition Dump 4.0 72.0 NA 5 Not in service 10 Smith Lake Bath House 6.0 320 84 55 - Potable water well 11 Relay Station (Intersection of Plant and Mott Lake Roads) ' NA NA NA 50 Not in service 12 Officer's Club Golf Course 6.0 89.2 41.4 75 Golf course irrigation well 13 Officer's Club Golf Course 6.0 84.5 38.8 105 Golf course irrigation well 14 Officer's Club Golf Course 6.0 63.0 11.5 107 Golf course irrigation well 15 Officer's Club Golf Course 6.0 81.6 17.3 107 Golf course irrigation well 16 Officer's Club Golf Course 6.0 78.0 28.8 65 Golf course irrigation well 17 Stryker Golf Course 6.0 164 23.5 170 Golf course irrigation well 18 Stryker Golf Course 6.0 152 34.9 72 Golf course irrigation well 19 Lake McKellar NA NA NA NA Not in service 20 Forestry Headquarters 6.0 114 67 NA Potable water well 21 Wildlife Headquarters 6.0 NA NA NA Potable water well 22 Aberdeen Camp NA NA NA 125 Potable water well 23 Ranger Station #40 6.0 600 NA NA Potable water well 24 Ranger Station #19 NA 300 NA NA Potable water well 25 OP 5 NA 500 NA NA Potable water well � ft bgs = feet below ground surface (bgs). bl NA --information not available. Note: The data on this table was drawn from USGS, 1999. SECTION 4 PREVIOUS INVESTIGATIONS AT SWMU 69 4.1 USGS RFI 1994-1999 Initial work performed in 1994-95 by the USGS as part of the RFI included surface geophysics, a soil -gas survey, completion of 28 soil borings, and the installation of 10 monitoring wells. Seven surface -water and six streambed sediment samples were collected for analysis during this initial investigation. Results from the initial. sampling revealed the presence of chlorinated solvents, pesticides, and petroleum -related compounds in the soil and groundwater. The chlorinated solvents tetrachloroethene (PCE) and trichloroethene (TCE) were the predominant contaminants detected in both soil and groundwater samples. In 1997, screening samples of both soil and groundwater downgradient from SWMU 69, were collected and analyzed in order to determine the location for "groundwater monitoring wells that were subsequently installed in order to further delineate groundwater contaminants. A second soil -gas survey was conducted in the area defined by the initial survey as having the highest concentrations of TCE, as well as an adjacent area north of SWMU 69. In 1997, 18 additional monitoring wells were installed in order to `eollect groundwater samples for laboratory analysis. These wells were screened in both surficial aquifers (the Upper and Lower Middendorf Formation) as well as the deeper confined aquifer (the Cape Fear Formation). This brought the total number of monitoring wells installed to 28. The 1999 RFI identified seven VOCs as chemicals of potential concern (COPCs) in the groundwater at SWMU 69. These were benzene, carbon tetrachloride, chloroform, 1,2-dichloroethane, 1,1,2,2-TeCA; PCE, and TCE. Of these COPCs, the chlorinated organic compounds (carbon tetrachloride, chloroform, 1,2-dichloroethane, 1,1,2,2-TeCA, PCE, and TCE) were the most prevalent. The concentrations of PCE and TCE were the highest of all analytes detected. COPCs were identified in 1999 by comparing analytical results to the USEPA Region III Risk Based Concentrations (RBCs) for tap water (USEPA, 1998), the USEPA Maximum Contaminant Levels (MCLs) (USEPA, 1996), and the NC Groundwater Standards (NCDENR, 1998). Three semi -volatile organic compounds (SVOCs) (bis(2- ethylhexyl)phthalate, 4-chloro-3-methylphenol, and n-nitrosodi-n-propylamine), one pesticide (dieldrin), and five metals (aluminum, iron, lead, manganese, and vanadium) were also identified as COPCs'in the groundwater. A total of 63 soils samples were collected by the USGS during their investigations and compared to the USEPA Region 3 RBCs. Three SVOCs (benzidine, benzo(a)pyrene, and benzo(g,h,i)perylene), one polychlorinated biphenyl (PCB) (Aroclor 1260), iron, and l 4-1 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc vanadium were identified as COPCs in the surface soils. No COPCs were identified in the subsurface soils. In 1998, surface -water and sediment samples were collected by the USGS from five locations along the Young Lake Tributary. 1,1,2,2-TeCA was detected in two surface - water samples collected from downstream surface water sampling locations. PCE and TCE were also detected at low estimated levels in the same two samples. Chloromethane and 1,1,2,2-TeCA were determined to be COPCs in the surface water in the two unnamed tributaries to Young Lake. The PCE and TCE' detections were below the screening criteria used at that time (USEPA Region III RBCs and the 1996 NCDENR Water Quality Standards Applicable to Surface Waters of North Carolina). TCE was detected in one of the sediment samples from the streambeds (below the screening criteria). The USGS concluded that the following COPCs identified in the groundwater: benzidine, benzo(a)pyrene, benzo(g,h,i)perylene, dieldrin, and Aroclor 1260, were not considered to be environmentally significant because of their limited distribution, low concentrations, and infrequent detections above the screening criteria. They also concluded that the chlorinated organic compounds had migrated to the north-northeast within the Middendorf aquifer to a discharge area at the tributary to Young Lake and to the underlying Cape Fear aquifer. The USGS Report recommended further definition of the chlorinated solvent contamination in the soil and groundwater. 4.2 SUPPLEMENTAL RFI (USACE) 2001-2002 The first phase of work for -the Supplemental RFI consisted of collecting soil samples from within the suspected source area as well as groundwater samples from the 28 existing groundwater wells. The second phase of this Supplemental RFI also collected a series of groundwater grab samples from numerous locations based on the conceptual site model (CSM) in order to further delineate the groundwater contamination. The data collected during this supplemental work is presented in the Site Conceptual Model Report for the Supplemental RF1Investigations of SWMU 69, Fort Bragg, NC (USACE, 2003). Selected figures and tables from the Supplemental RFI are presented for informational purposes in Appendix A of this study. 4.2.1 Surface and Subsurface Soil Twenty-four soil borings were completed throughout the suspected source area on 50- foot centers. Continuous soil samples were collected at each boring from the surface to just above the water table (generally a depth of 38 feet) and screened with a photoionization detector (PID) and flame ionization detector (FID) for organic vapors. There were no significant detections of organic vapors with either the PID or FID. A total of 24 surface soil and 54 subsurface soil samples were collected for laboratory analysis from the borings based on'the PID and FID responses. If a positive response was detected while screening the soils, then a sample was collected for VOC analysis from that interval. If there was a positive response for the entire depth -of a boring, up to three soil samples were collected in order to provide vertical delineation. If there was no PID response, one sample was collected from a depth that was just above the water table. Samples collected from the borings `were analyzed for VOCs, SVOCs, PCBs, and chlorinated pesticides, based on results from the previous investigations. Results of the soil analyses were compared to the USEPA Region 9 Preliminary Remediation Goals r 4-2 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\f1na1\Fina1 SWMU69 CMS.doc (PRGs) for residential soils and to the North Carolina Soil to Groundwater concentrations (NCDENR, 1998) (Appendix A, Table 4.1). Five pesticide compounds (dieldrin, aldrin, methyoxychlor, 4'4-DDE and 4'4-DDT) and five SVOC compounds (benzo(a)anthracene, chrysene, fluoranthene, phenanthrene, and pyrene) were detected in some samples. Aroclor-1260 was the only PCB detected -in the soils. Seventeen VOCs were detected at least, once in the 78 samples: 1,2,3- trichlorobenzene, 1,2,4-trichloroebenzene, . 1,2,4-trimethylbenzene, 1,3,5- trimethylbenzene, 1,3-dichloropeopane, 1,4-dichlorobenzene, 2-butanone, acetone, chloroform, chloromethane, methyl-tert-butyl-ether (MTBE), naphthalene, styrene, tetrachloroethene, trichloroethene, toluene, and total xylenes. TCE, PCE and toluene were detected most frequently. None of the analytes detected in either the surface or subsurface soil samples exceeded the USEPA Region 9 PRG screening values. Two compounds, dieldrin and TCE, had detections that exceeded the NC Soil to Groundwater Concentrations. TCE exceeded the NC soil to groundwater value (18.3 microgram(s) per kilogram [µg/kg]) in 8 of the 54 subsurface samples and dieldrin exceeded this value (1.13 µg/kg) in 10 subsurface soil samples. Seven of these dieldrin detections are thought to be the result of laboratory contamination, as dieldrin was also detected in the laboratory method blank at 1.3 µg/kg. Detections of TCE above the NC soil screening level ranged from 19 to 54 µg/kg, with one detection of 110 jig/kg. The detections of dieldrin ranged from 2 to 45 jig/kg. The depth of the groundwater in this area of SWMU 69 averages 38.5 feet bgs. Only two of the detections of dieldrin and TCE that exceeded the soil to groundwater criteria were from depths of 35-36 feet bgs, the remaining detections were all from depths between 4 to 25 feet bgs, with concentrations declining with depth in the samples:: collected below 25 feet bgs. There was no correlation between any elevated PID response and the concentrations of the VOCs detected in the soil samples. Nor did any concentrations. of TCE appear to correlate directly with the amount of clay in any soil samples, although the two highest concentrations of WE were from samples that contained stiff gray clay, one a surface sample and one from 35 to 36 feet bgs. There were no COPCs identified in the subsurface soils during the initial RFI and the excess lifetime cancer risk (ELCR) calculated for human receptors to the surface soils were within range of acceptable risk levels. Based on the infrequent detection of COPCs in the soils during the Supplemental RFI and the low levels detected, it was concluded that the soils at SWMU 69 do not to pose a risk to human receptors. Therefore, it was concluded that no corrective action was necessary (USACE, 2006). 4.2.2 Groundwater The second phase of the Supplemental RFI consisted of installing piezometers to obtain more detailed information about the groundwater elevations across the area. Groundwater grab samples were also collected using direct push technology. Following the EPA Triad methodology, samples were analyzed in the field in order to provide real- time data. These field results were to determine where the next sampling point would be located. This phase of the Supplemental RFI was conducted in order to determine if these -- } 4-3 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\final\Final SWMU69 CMS.doc areas of higher concentrations were indicative of past source areas or if they represented zones of residual dense non -aqueous phase liquid (DNAPL). A total of 22 piezometers were installed around the area of the two small streams and the area south of Butner Road in order to obtain more detailed information concerning the direction of groundwater flow in this area and to construct a more realistic potentiometric surface. Initial groundwater samples for field analyses were collected from the 22 piezometer locations. A direct-sparging ion -trap mass spectrometer was used to analyze groundwater samples using EPA Method SW8265. A total of 81 primary samples were collected and analyzed for TCE, PCE, and cis-1,2-dichloroethene (cis-1,2-DCE), based on the results of the previous investigations. Lines of evidence for natural attenuation include the increase of the daughter compound and decrease of the parent compound in the downgradient direction, indicating that attenuation and degradation processes may be occurring in the subsurface as the dissolved contaminants travel away from the source area. The concentrations of TCE have increased relative to PCE in the samples collected from the locations farthest downgradient to SWMU 69 (G-6, G-44, and 69MW 19D) for those samples that contain concentrations of both PCE and TCE. This may indicate that natural attenuation is occurring, or could be the result of PCE's greater affinity for sorption sites (i.e., higher retardation factor) than TCE. Figure 4.1 presents groundwater analytical data collected from site monitoring wells and grab samples collected using direct push drilling methods. Figure 4.2 depicts the interpreted extent of the SWMU69 VOC plume based on the direct push grab sampling groundwater monitoring well sampling conducted in 2001. The interpreted plume extent depicted in Figure 4.2 encompasses a total area of approximately 36 acres, as defined by the 1 µg/L TCE contour. In addition , a total of 5 CAH hot spots .were defined based on data collected in 2001 (Figure 4.2). Results from this event provided a more detailed vertical and horizontal delineation of the PCE/TCE in the groundwater and support the conclusion that the chlorinated solvent contamination detected in the groundwater could be from two or more separate releases. Widespread minor concentrations are most likely remnants of previous small releases. In this case, dispersion and dilution processes were the major contributors to the degradation processes because of the subsurface conditions. Areas of significantly higher concentrations detected during this event coincided with those previously reported. Dissolved levels of PCE/TCE detected in the ' groundwater do not approach concentrations that would indicate the presence of dense non -aqueous phase liquids (Cohen and Mercier, 1993). 4.3 2004 SAMPLING EVENT The Supplemental RFI recommended that an additional groundwater well be installed downgradient of 69MW-21D toward Young Lake to define the downgradient extend 'of the VOCs in the groundwater. In 2004, a decision was made by Fort Bragg to obtain groundwater samples from downgradient locations and install downgradient wells using direct push methods. A very stiff clay layer was encountered during these well installations and only grab samples could be obtained using the direct push equipment. Three groundwater grab samples were collected, two from the west side of the tributary for Young's Lake and one from the east side. Ten existing wells were sampled at this time and three surface water samples were collected. Results of the groundwater grab sample collected from the most downgradient _ 4-4 JJ SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\ftna1\Fina1 SWMU69 CMS.doc PA - 1i2� 2 # 4.41 0 12M- A I / b \ 0 Su iTss-ice L � n { S 1 I ass 1� j �r t� \ j I I � aG lk ti .P 20Y 0 20U 400' LEGEND. ,�f SCALE IN FEET r MONITORING WELL LOCATION'S FIGURE .4.1 69iMW I WITH CONCENTRATIONS P-10, PIEZOMETER LOCATIONS PCE AND TOE CONCENTRATIONS DETECTED GROUND -WATER GRAB. SAMPLE IN GROUNDWATER _y LOCATIONS ` Corrective Measures Study t� Fort Bragg,, North Carolina ( c El r: %CE i TCr DEPTH OF SAIUIPLE, �I PARSONS E:C ! PCEfTCONCENTRATIONS Source: USACE, 2006.. Denver, .Colorado irawX 446 SWMU 69.Suiface Map.cdcros 5107107 pg 4_ 4-5 orally left blank North LEGEND IM14 MONITORING WELL WITH - 69MWI PCE/TCE CONCENTRATIONS (21/42) IN U9/L N� tea- 6; A GEOPRO$E GRAB SAMPLE 69 . 69TW10 LOCATIONS WITH PCE/TCE (ND/2.4) CONCENTRATIONS Its Ug/L TCE ISOCONCENTRATION — �60� CONTOUR IN pg]L, (DASHED WHERE APPROXIMATE) 6201 (.NO asp %v (f 1 �f .x 6, � r e 69 Q MW22D.... (2.! 4` •30J/3.43 eb u 22C (ND 4.3) 69MW3 (ND/ND) �ti aaP A � ttc m % \ %174 ssov 293X e e •iva g 1t i .9azsi C � Z. � eaii t Masi Y o°�"u I Source: USACE, 2006 dmVA745446 SW(NU 69 Suiface 6 D/ND) (ND/ND) 200 0 200' 400' SCALE 1N FEET FIGURE 4.2 SVVMU-69 TCE CONCENTRATIONS CONTOURS IN MIDDF-NDORF FORMATION (,pg1L) (AUG 201) Corrective Meas"Tes Study vt Fort Bragg, NDrth Carolina PARSONS Map.cdima 5iO8/07 pg 5 Tonally left blank location on the west side of the stream were non -detect; however, TCE was detected on the east side of the stream. Results from the 2004 sampling event are presented on Appendix A, Table B-1, along with figures showing the location of the grab samples (69TMW23, 69TMW24, and 69TMW25). Analytical results from the monitoring wells sampled were similar to previous sampling results. NCDENR has requested that a permanent well be installed in the downgradient area of SWMU 69 north of Butner Road. The purpose of this new well will be to act as a sentry well below the toe of the SWMU69 plume and will act as a sampling point to determine if the SWMU69 plume is migrating in the downgradient direction. The proposed location of this well (to be installed by conventional drilling methods) is presented in Section 10 as part of each remedial alternative under consideration. The proposed well location -is based on the results of the downgradient grab samples and discussions with NCDENR. All lab data, field sampling data sheets, and the Quality Control/Quality Assurance (QC/QA) Report for this data are located in Appendix E of USACE, 2006. 4.4 2007 GROUNDWATER SAMPLING EVENT A groundwater monitoring event was conducted in February 2007 to further delineate the SWMU 69 COC plume and to collect an up -to; -date data set to support the SWMU 69 remedial design. Table 4.1 summarizes the VOC data collected during this sampling event.- The 'February 2007 TCE in groundwater data set is also depicted on Figure 4.3 along with an updated plume foot print. During the February 2007 sampling event PCE and TCE were detected at concentrations above the NC 2L standards at a total of 5 and 9 locations, respectively. The maximum PCE concentration of 13.8 µg/L was detected at 69MW17S while the maximum TCE concentration of 53.7 µg/L was detected at 69MW 18D. '-1,1,2,2-TeCA was also detected at 2 locations at concentrations that exceeded the NC 2L standard, with a maximum detected concentration of 3.31 µg/L (69MW22D). The .primary contaminant concentration data collected at SWMU69 (PCE, TCE, cis- 1,2-DCE, and 1,1,2,2-TeCA) is tabulated in Table 4.1. In addition, COC concentration trend plots have been prepared for each monitoring well at SWMU69 and are presented as Appendix D. Most of the monitoring wells at SWMU69 have been sampled relatively sporadically since approximately 1998, with a few monitoring wells sampled as far back as 1995. PCE and TCE concentrations at the majority of monitoring wells have been generally decreasing for at least the last 5 to 6 years, with the notable exceptions of monitoring wells 69MW 12, 69MW i 6S, and 69MW 19D, and potentially 69MW 18D. 4.5 SURFACE WATER AND SEDIMENT Two unnamed intermittent streams (termed "unnamed Young Lake Tributaries" by the USGS) drain the hillside north of SWMU 69. Both streams empty their contents eventually into Young Lake, located approximately 1 mile to the north-northeast. The surficial groundwater located in the upper and lower Middendorf Formation is the primary source of surface water in the streams. During heavy rain events the streams also collect surface runoff from the SWMU 69 area as well as the area to the north,of SWMU 69. A total of fifteen surface -water samples have been collected during the various r' investigative phases of SWMU 69. Figure 4.4 shows the locations of each sample and t� 4-9 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc presents a summary of the analytical results. Five samples were collected in 1998, four `- samples in 2001 (an additional sample was planned; however, the stream was dry in that location), and three samples in 2003. Three additional samples were collected in 2006. the analytical data for these samples is summarized in Table 4.2. Several of these samples have been collected from the same location over a period of eight years (Figure 4.4). Both surface -water and sediment samples collected in 2001 and 2003 were from the same locations as the samples collected by the USGS in order to confirm the previous detections. Table 4.2 summarizes the surface water detections and compares these results to the NCDENR screening criteria for protection of human health as described by North Carolina Rule 15A NCAC 213, updated in 2004. 1,1,2,2-TeCA, PCE, TCE, and cis-1,2— DCE have all been detected sporadically in the surface water. TCE was detected in the surface -water samples from the sampling location most downgradient to SWMU 69 in both 1998 and 2001 (Figure 4.4). In 1998, 1,1,2,2-TeCA was detected in two surface -water samples. TCE was detected during the 2001 sampling event in the sediment sample 69SD 1 from a location near MW21 D, downgradient of SWMU 69, at 5.6J µg/kg. TCE was also detected in the surface -water sample collected from this same location. TCE was not detected at this location in the 2003 sampling event, but was detected again during the most recent sampling event in 2006. This location is also immediately adjacent to Butner Road (a major thoroughfare at Fort Bragg). Storm water runoff from the road and surrounding area is funneled into the stream at this point. None of these detections have exceeded the NCDENR screening criteria for protection of human health indicating that the surface water at SWMU 69 does not present a risk to human receptors. 4.6 HRC PILOT APPLICATION RESULTS In September, 2005 an organic substrate addition pilot study was conducted at SWMU 69 in order to determine if the technology was effective at inducing and maintaining anaerobic reductive dechlorination of PCE and TCE in groundwater. The commercial product Hydrogen Release CompoundTM (HRCTM) was selected as the organic substrate of choice for the SWMU 69 organic substrate addition pilot program. Four "hot spot" areas were selected based on historic groundwater data for the application, of HRCTM. The four hot spot areas chosen are located in close proximity to site monitoring wells 69MW-19D, 69MW-17S/D, 69MW-6, and 69MW-1/9 (Figure 4.1). One baseline groundwater sampling event was conducted at 10 monitoring wells prior to HRCTM injection to document natural site geochemical and contaminant conditions to serve as a comparison point for data collected after injection. After the baseline sampling event was complete HRCTM was injected through direct push drilling methods in a series of 16 injection points installed in a grid -based treatment cell and located 20 feet upgradient from each monitoring well location. The HRCTM injection points within each treatment cell were arranged in an offset pattern of 4 rows spaced 10 feet apart with 4 injection. points in each row. The location of the injection points had to be rearranged slightly for the area upgradient of 69MW6 due to the close proximity of this monitoring well to Woodruff Street and the numerous underground utilities in this area. HRC® was injected at a rate of approximately 4 pounds (lbs) per foot within a 17-foot zone ranging from 34 to 51 feet bgs at 69MW-1/69MW9 -and 4-10 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc .2 VrrAMW3 vmmwi 7"-- VrTAMJ Q 69MW7 _7 1-I 59MVVb _'j co 0' 69MW2 ND 0MW9 "'0.99J VV �'69M 69MW22 SWMU. 60 69MW1 69 MuJ t7A 69MW22C I 59P 2.3- 6 MU I W10 2.5 Legend * Groundwater Monitoring Well -and TCE C An asterisk indicatet a tarhoo rary well installatit * Surface Water Sample- Locations Rail Roads Stream 69TMW23 TCE QoncentraUon ContoUr. 1.0 ug/L 5 10 url/L inferred 12MW4 12MW3 vrTAmW4 Q;,'- vrTAmW5 /\T,MMW6 E) vrTAmwl2 VTTAMW8 AEHAV-2 VrTAMW1 0 vrTAmvvg AEHAV-3 17 VrrAMW1_1 sk 12MW9 SWMU-69 20 ug/L Corrective Measures Study TCE CONCENTRATIONS 50 ug/L DETECTED IN GROUNDWATER FEBRUARY, 2007 3: _w 0 310 620 FT. BRAGG, NORTH CAROLINA 4 Feet CHSCKEDBY D.Giffiths inch equals 300 feet. 'JSONS DRAFTED BY CtenBraakv FILE. SWVU-6S_TCE_Feb2I DATE 61=7 FIGURE 4-11 i A 411 A DP23 X;. D SWMU 69 C 12MM e9mm 2 MW4 5 AN V 89T 30 Ir YLT5 low eqSM 2004 i4 4/ AIND - e9SW4 2001! RESULTS r > ChlaMmot" o rn TOWN Telradoviftm TrIchlarostarm A-7 300' 0 3w 600 LEGEND North ► SCALE IN FEET FIGURE 4.4 MONITORING WELL SWMU - 69 SUMMARY OF SURFACE WATER PIEZOMETER ANALYTICAL RESULTS 1998-2006 GRAB SAMPLE Corrective Measures Study Fort Bragg, North Carolina SURFACE WATER SAMPLE LOCATIONS I PARSONS Source: USACE, 2006. Denver, Colorado draw%745446 SWMU 69 Surface Map.cdr ma 5107107 pg 2 4-13 orally left blank a ,O O, 1D a ,O a w a ,O a ,O m ,O a ,O a 10 a, ,O 0, ,O z z O O y O ,O O o m m obi C IN NE 0 n C 3 E d y N N N m G aL, " n W O VWi C O A vOi C O O in �• in O, O O O O, G C N p W C VAi C O A N C N C .A.. 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So Nz--^--zzozzzzozzzzzzzzz51pPPzzzzzzzzzzozzzzozzzzzzzzz'rzPzz�N �o�v-'wwNvv�aaaaiaaaasaaaae��vvaaaaaaaa�aaaa"aaaaaaaaa�-v;vv v to n 0 n O O O �d O N z "z O N `Z z z z Z z z O z z Z Z Z z Z z z a a a a z z z z a a a a O z A z ,^ O d 0 O A z 7. 7i a a a Z z Z z z a a a a a O z z z z z N a a a a a a a a N ,- o J N a a N N a a a a a a a„ a a a a a N N O ?i a TABLE 4.1 (Continued) t` SUMMARY OF SELECTED VOCS IN GROUNDWATER SWMU69 FORT BRAGG, NORTH CAROLINA Screen Interval (ft below ground PCE v TCE cis-1,2-DCE d 1,1,2,2-TeCA y Well Location surface) Sampling Round (µg/L) d (µg/L) (µg/L) (µg/L) 69MW20D 32.0-42.0 August-98 0.181 0.181 NA ND October-00', 1 ND ND NA ND August-01 0.471 ND NA ND September-02 ND ND NA 0.75J June-04 ND ND NA ND 69MW21C 145.0- 165.0 August-98 0.47.1 ND NA NA October-00 ND ND NA NA August-01 ND ND NA NA Se tember-02 ND ND NA NA 69MW2ID 30.0-40.0 August-98 0.35.1 70 NA NA October-00 ND 26.9 NA NA August-01 0.36 51 NA NA September-02 0.42.1 20 NA NA June-04 ND 30 1.2 ND Februa -07 0.341 45 1.37.1 <0.12 69MW22C 184.0- 194.0 August-98 0.351 21 NA NA October-00 ND ND NA NA August-01 ND 4.3 NA NA September-02 ND 11 NA NA Februa -07 <0.15 4.64 <0.29 <0.12 69MW22D 66.0-76.0 August-98 0.151 1.5 NA NA October-00 ND 3.1 NA NA August-01 0.30.1 3.4 NA NA September-02 ND 3.9 NA NA June-04 ND 1.7 NA 6.2 Febtua -07 <0.15 1.591 <0.29 331 69TMW23 June-04 NA NA NA NA 69TMW24 June-04 NA 18 NA NA 69TMW25 June-04 NA 14 0.82J NA m PCE = tetrachloroethene, TCE = trichloroethene, DCE = dichloroethene, and TeCA = tetrachloroethane mg/L = micrograms per liter. d The NC 2L standard contains methodologies to calculate cleanup criteria other than the default 2L values. The default 21,numerical values are included in this table for reference. d/ J-flag indicates the detected concentration is greated than the method detection limit and less than the method reporting limit. The concentration is therefore estimated. NA = not available. "<" indicates that the analyte was not detected at a concentration greater than the indicated method detection limit. ND = indicates that the analyte was not detected at a concentration greater than the method detection limit. In this case the method detection limit was not available. 4-17 Table 4.2 Summary of Surface Water Data and Associated Regulatory Criteria SWMU69 Location: NC Screening Standards I SWMU-69 SWMU-69 SWMU-69 SWMU-69 SWMU-69 SWMU-69 SWMU-69 SWMU-69 SWMU-69 Current Sample No.: I Surface Water Surface Wate YLT2-SW2 YLT3-SWI YLT4-SW1 YLT5-SWl YLT6-SW1 69SW1 127-Aug-01 69SW2 69SW3 I 69SW4 Sam lin Date: Standard Source 12-Au -98 12-Au -98 12-Au -98 12-Au -98 12-Au -98 27-Au -01 27-Au -01 27-Au -01 VOCs 8260B) 1,12,2-Tetrachloroethane ggtL 10.8 NCHH 1.0 - U 1.4 - U - U 1.2 - U - U - U Chloromethane NL NL -U - U - U - U - U - U 0.4 - U 0.71 J cis-l2-Dichloroethene 13,000 NCHH -U -U -U -U -U -U -U -U -U Toluene 11.0 NCHH -U -U -U -U -U -U 0.8 -U -U etrachloroethene 8.9 NRW C -U -U 0.15 J -U -U -U -U -U -U Trichloroethene RgIL 92.4 NCHH 1.1 -U 1.3 -U -U 1.3 -U -U -U Location: NC Screening Standards I SWMU-69 I SWMU-69 I SWMU-69 I SWMU-69 I SWMU-69 SWMU-69 Sample No.: 69SW7 69SW8 69SW9 SW106 SW206 SW306 Surface Water Surface Water Sampling Date: Standard Source 12-Au-98 12-Au -98 12-Au -98 6-Mar-06 6-Mar-06 6-Mar-06 VOCs 8260B 1.1,2,2-Tetrachloroethane 10.8 NCHH - U - U - U - U - U 0.27 J Chloromethane L NL NL - U - U - U - U -U -U cis-1,2-Dichloroethene 13,000 NCHH -U -U -U 0.23 J 0.24 J - U Toluene 11.0 NCHH - U - U - U - U - U - U etrachloroethene 8.9 NRW C - U - U - U - U - U - U Trichloroethene 92.4 NCHH - U - U - U 0.87 J 0.85 J 0.85 J DATA OUALIFIER CODES: J = Analyte positively identified; numerical value is approximate (below quantitation limit, but above method detection limit). U = Analyzed for, but not detected above quantitation limit. NS = Not Sampled. NOTES: NCAL = Surface Water Criteria based on North Carolina Aquatic Life Surface Water Standards, 2B. NCHH = Surface Water Criteria based on North Carolina Human Health Water Standards, 2B. NRWQC = EPA National Recommended Water Quality Standards. NL = Not listed. /J'i 69MW-6, from 22-39 feet bgs at 69MW17S/69MW17D, and from 20-37 feet bgs at 69MW 19D. After HRCTM injection activities were complete groundwater samples were collected from the six wells adjacent to the four injection areas as well as monitoring wells located downgradient from the injection areas to monitor the performance of the HRC. Process monitoring groundwater sampling events were collected at approximately 5-months and 7-months post injection. Performance ..monitoring analytes included VOCs and the geochemical parameters nitrate/nitrite, sulfate/sulfide, dissolved iron, total organic carbon (TOC), chloride, methane/ethane/ethene, and the field parameters (pH, oxidation reduction potential [ORP], specific conductivity, dissolved oxygen [DO], and temperature). During the first 7 months of pilot study performance monitoring it became apparent that groundwater geochemistry was not being impacted at two of the pilot test areas (areas associated with wells 69MW-19D and 69MW-17S/D) as evidenced by the lack of measurable increases in TOC concentration and the lack of significant geochemical changes. Groundwater geochemistry was positively impacted at hot spots associated with wells 69MW-1 and 69MW-6 in that TOC concentrations increased and geochemical conditions became more reducing and therefore more conducive to reductive dechlorination-. , However, formation of cis-1,2-DCE daughter products, key evidence of the onset of reductive dechlorination, was not observed in the first 7 months of performance monitoring. In addition, TCE concentrations -increased slightly at each of the impacted study areas and TOC concentrations declined significantly between the 4 month and 7 month events. This data indicates that there was limited desorption of contaminant mass from the soil matrix due to the presence of organic carbon derived from the HRCTM and that the emplaced HRCTM did not provide adequate organic carbon to the system to induce reductive dechlorination. In addition, the decline in TOC concentrations between 4-months and 7-months indicates that the emplaced HRCTM will not produce sufficient TOC in the longer term. Based on review of the pilot study data, the HRCTM injection was unsuccessful in the first 7-months for a number of reasons: • HRCTM may not be an optimal organic substrate for use at this site because groundwater flow rates are relatively fast at SMWU 69, resulting in rapid dilution and dispersion of the soluble lactic acid produced as the HRCTM is dissolved. • The HRCTM loading rate of 4 pounds per foot was too low for this site given that groundwater flow rates are relatively rapid and given that the natural geochemical conditions are moderately to strongly aerobic. • The monitoring time period for the pilot system was not sufficient to determine whether anaerobic dechlorination could be stimulated. The naturally aerobic geochemical conditions at SWMU 69 will result in a relatively long acclimation period between the injection and the observance of complete reductive dechlorination. This lag time could be on the order of 12 to 24 months because of the time required to develop the proper anaerobic geochemical conditions and for the growth and development of a suitable anaerobic microbial population for reductive dechlorination of PCE and TCE. l 4-19 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc Finally, the pH of the groundwater in the reaction areas was not properly buffered. Microbial strains known to be capable of complete dechlorination of PCE and TCE are most effective in neutral pH conditions (pH greater than 6.2) ((Volkering, 2004), making pH buffering an important factor in a successful enhanced bioremediation application. pH data collected during the course of the HRCTM pilot indicates that pH was depressed as low as approximately 4.1 as a result of the HRCTM injection. These acidic conditions resulted in the production of low pH fermentation products 2-butanone and acetone and likely precluded significant reductive dechlorination. The results of the pilot study indicate that organic substrate addition is a viable technology at SWMU 69 based on the short term geochemical shifts observed in monitoring wells 69MW-1, 69MW-6, and 69MW-9. However, the pilot study results also indicate that HRCTM is a non -optimal organic substrate for use at SWMU 69. Vegetable oil has been applied as a low-cost organic substrate at numerous sites in the past 8 years with very good results. Vegetable oil has proven to be a excellent substrate that is capable of delivering relatively high organic carbon loading over the long term (5 to 7 years). Thus, the organic substrate addition technology should be considered for potential application at SWMU 69 provided that vegetable oil or some other more appropriate organic substrate is applied in place of HRCTM. 4-20 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\final\Final SWMU69 CMS.doc SECTION 5 SITE CONCEPTUAL MODEL 5.1 SWMU 69 SITE CONCEPTUAL MODEL There is no information available concerning the composition or quantities of the solvents released at SWMU 69. The time frame during which the releases occurred is also unknown. Therefore; it is unknown whether the material released could have been a mixture of two or more compounds or a single compound, i.e. the material released could have been pure PCE or a mixture of PCE and TCE. Given the low concentrations of TCE and PCE detected in the soils and groundwater at SWNW 69, it is unlikely that this contamination is the result of one large spill. The most likely site model is that many small spills or leaks occurred in and around SWMU 69 from various activities over a long period,of time. TCE and PCE both belong to the group of compounds known as chlorinated aliphatic hydrocarbons (CAHs), have a density greater than water (greater than 1.0 gram(s) per cubic centimeter [g/cm3])and are commonly referred to as DNAPLs. TCE and PCE have been most frequently used as solvents for degreasing and cleaning in the past. Chlorinated solvents can migrate large vertical distances through the vadose zone. Because they are denser than water, these compounds will continue to migrate in a vertical direction after reaching the saturated zone. Within the saturated zone, the interaction of groundwater flowing through DNAPL that is pooled or sorbed to soils will result in a dissolved phase "plume." The orientation of the plume will depend on the direction of groundwater flow and the vertical distributions of hydraulic characteristics of the aquifer. The potential for contaminants in the surface and subsurface soils to leach to groundwater was evaluated by comparing the maximum concentrations in the surface and subsurface soil to North Carolina soil screening levels (SSL) (USACE, 2003). Concentrations above these standards indicate that the constituent might be released to the groundwater, resulting in concentrations in the groundwater that could be harmful to human health. TCE exceeded the SSLs at the suspected source area and has been detected in the groundwater. Soil samples were not collected at areas outside of the fenced SWMU 69 compound. Chlorinated solvents are not stable when introduced to the soil and groundwater environments and will undergo either biotic or: abiotic degradation. This degradation is a, result of a series of chemical reactions that produce new compounds (daughter products). The presence of both the parent and daughter products generally indicate that one or more of these degradation processes are occurring (Wiedemeier, 1999). A single chlorinated solvent plume can exhibit different types of behavior in different -- portions of the plume. Although conceptual models of field sites often portray well- 5-1 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc defined zones containing different oxidation-reduction environments, in reality aquifers are heterogeneous and poorly mixed. Therefore, the oxidation-reduction potential can vary greatly over a small scale within the aquifer (Wiedemeier, 1999). Several small spills would behave as several instantaneous sources. With time and the effects of dispersion and diffusion, these individual spills could lead to plumes that have more than one zone containing higher concentrations of dissolved contaminants. The mixing of plumes from small spills could also result in zones that contain differing mixtures of dissolved contaminants -if the sources were different materials. Multiple spills from the various activities conducted in the past in and around SWMU 69 could possibly coalesce in the groundwater to form. a wider spread plume than would have been expected from just one spill. Detections of 1,1,2,2-TeCA support this scenario. 1,1,2,2- TeCA has been detected sporadically in all sampling events and was detected in samples from five monitoring wells during the 2002 sampling event. Three of these detections were from wells in upgradient locations to SWMU 69 and the SWMU 69 plume, and from hydraulically distinctly separate areas (69MW-22D, 69MW-18D, and 69MW-20D). An alternative explanation for the large groundwater plume detected during the investigation of SWMU. 69 would be two or more plumes that are the result of two or more distinct sources. PCE, TCE, 1,1,2,2-TeCA and carbon tetrachloride are all common chlorinated solvents used for cleaning (including dry cleaning) and degreasing a variety of materials during the past 40 to 50 years. 5.2 NATURAL ATTENUATION EVALUATION FOR COCS IN GROUNDWATER The primary process for the natural attenuation of the highly chlorinated: compounds (e.g., PCE, TCE, and 1,1,2,2-TeCA) is biologically mediated sequential anaerobic : reductive dechlorination. This process involves the microbially mediated transformations of chlorinated solvents under anaerobic conditions (without oxygen) that convert highly chlorinated solvent species to less chlorinated solvent species by replacing chlorine atoms with hydrogen atoms. For example, the chlorinated ethene chain is sequentially dechlorinated from the parent compound PCE through TCE, cis-1,2-DCE, VC, to the reaction end product ethene. Reductive dechlorination only occurs under anaerobic conditions where dissolved oxygen is absent and where the groundwater ORP is below zero. Figure 5.1 presents the chemical and biological breakdown pathways for the predominant contaminants in groundwater at SWMU 69. Anaerobic reductive dechlorination breakdown products of PCE, and TCE (cis-1,2- DCE, trans-1,2-DCE; vinyl chloride [VC]) have historically been infrequently detected at very low concentrations at SWMU _69, indicating. that only very limited reductive dechlorination of PCE' and TCE may have occurred. PCE and TCE remain the dominant contaminants detected in groundwater at all monitoring locations associated with SWMU 69, indicating that anaerobic reductive dechlorination is likely not occurring at a significant rate at this site. In addition, groundwater geochemical data collected during the course of site investigations at SWMU 69 indicate that natural conditions beneath the site are aerobic, with DO concentrations ranging from 4 to 8 milligrams per liter (mg/L) and ORP conditions ranging from +100 to +350 millivolts. These geochemical conditions are not conducive to anaerobic processes including reductive dechlorination, supporting the assertion that anaerobic reductive dechlorination is not occurring and is not likely to occur naturally on this site. 5-2 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc 1,7,�r2 t�t��c4rlo�i6arti� -.__ . .(7eCA) - 46'. , )} H H. -� 4r1nh1Gr�elhan3: Cl Cl (TCE) . H Cl ('t')2TOA). .i �� 11 cls-1,22 � � `,:, r3lchiorc�i6tonc� dichlor�rhann .a�lchto►o®4hnrle�' Cl Cl: ' s Cf 7,-dichlordathans MIX* N Cl � CI Ct \H (,bDCE)(tl)CE} H—i— =H i Cl Cl viny9 obtorid® t�trbotn dtoxiate (C0�):. . vH raiathane`(CHq) .': �ti G C owathana ati1ana r� �y . . H H H \H :5 Mhana: li H . _I H H EXPLANATION ANAGmmicOXIDATImHYORl1GENOLY515 : [71CIILOR(JELIiUIINATiOFI f7tHYf7ROCWLc3FlINAiION. $�fi�fd�BS�ldya� r�F 7`��.il< t��C/9'.Ft�f113®1B' L ; ToCA HYElROGENOLYSIS YO,112TCA'ANG 1200A tf�k• 'fGCA HYDR0135NOLYSIRTO1112TCA FOLLC1WIM f Y r .DICHLOROELIMMArION CF. i1,5:1 CA TO VC' TEA-DICE:iLOADELIMINAATION TO i )CF AN13 MCE (±1) ToCA DEHYDROC-1-ILORINATION TO TOE Nio lf- led'frc;m Chen and others.(1996). and Uegel and others (1987). 16 Anaerobic Patmvays-cdr ma-1/30107 f' Other natural attenuation processes that may be occurring at SWMU-69 include abiotic aerobic destruction mechanisms and non-destructive mechanisms such as dilution, dispersion, volatilization, and sorption. Limited historic groundwater analytical data (Appendix A, Tables 4.2 and B-1) indicates that contaminant of concern (COC) concentrations have decreased over time at some well locations (e.g., 69MW-10, 69MW- 12, 69MW-18, and 69MW-21D). These observed decreases in COC concentrations indicate that some or all of the non-destructive natural attenuation mechanisms and potentially abiotic aerobic degradation may be occurring at SWMU 69. 5.3 HUMAN HEALTH RISK EVALUATION A human health risk assessment was performed by ABB, INC. in 1995 after the initial RCRA RFI was performed (USACE 2006). The incremental life time cancer risk (ILCR) for carcinogens and hazard index for non -carcinogens were calculated for exposure of future excavation workers to surface soils, and adult and child residents to surface soils, subsurface soils, and groundwater. There were no human health COPCs identified for subsurface soils. For the excavation worker, the ILCR associated with exposure to surface soils was 7 x 10-8 and had a hazard index (HI) of 0.01. Both the adult and child resident exposure to surface soils was ,1 x 10-5. Hazard Indices were 0.16 and 0.6, respectively. Incremental levels of risk for workers were minimal and all levels are within the USEPA Region 4's levels of acceptable risk (1 x 10-5 to 1 x 10-4) and require no corrective action. This site currently has an industrial use, is covered in gravel and asphalt, and is behind a locked fence. Because this site has a non-residential use, there are no current risks to residential receptors. Risks for residential receptors for the groundwaterpathwaywere also calculated. The m%or contributors to a cancer risk exceeding the 10' level were tetrachloroethene (3 x 10- ), trichloroethene (3 x 10-5), chloroform (2 x 10-5) and arsenic (5 x 104). Because arsenic is a naturally occurring element in the Middendorf Formation, ABB (1995) concluded that the risk attributable to arsenic was overestimated. Also, arsenic was only detected in 3 of the 28 groundwater samples and all arsenic levels detected were below the USEPA MCLs and NC 2L values. Risks for future receptors for the groundwater pathway were reevaluated using the more current 2002 sampling data. Currently, drinking water at Fort Bragg is from surface water sources. Therefore, the pathway is not complete for groundwater and no risk to current human receptors exists for groundwater. However, there is some potential for future groundwater contaminant plume discharge to the unnamed tributaries to Young Lake, which would pose a risk to surface water receptors. In addition, the state of North Carolina requires that groundwater be remediated to the NC Groundwater 21, standards, thus remediation is warranted on this site. Tables supporting the risk calculations are located in Appendix B. Table 5.1 below is a summary of the risks for all future receptors (assuming that the future installation worker would be drinking groundwater). Exposure point concentrations (EPC) were calculated by using the arithmetic average of the groundwater concentrations for each of the four COPCs following EPA Region 4 guidance. These averages were calculated by using a value equal to %2 the reporting limit for those samples that did not have a detection reported. Table C-10, located in Appendix B, shows the calculations of the exposure point concentrations. Groundwater data from 5-4 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\ftna1\Fina1 SWMU69 CMS.doc welts upgradient of the SWMU 69 (69MW7, 69MW22D, 69MW20) were omitted as well as data from wells completed in the lower Cape Fear aquifer (69MW8, 69MW22C, 69MW21C). The EPC is considered to be reasonable maximum exposure (RME) for future receptors to the groundwater. Table 5.1 Summary of Carcinogenic and Non -Carcinogenic Risks for all Receptors for the Groundwater Pathway Fort Bragg, North Carolina Chemical of Concern Carcinogenic Non -Carcinogenic Child Resident Adult Resident Installation Worker Child Resident Adult Resident Installation Worker Tetrachloroethene 1.21 x 10-5 3.96 x 10-5 1.09 x 10-5 0.023 0.001 -- Trichloroethene 1.74 x 10-6 1.82 x 10-6- 4.90 x 10-6 0.403 0.017 -- 1,1,2,2- Tetrachloroethane 4.63 x 10-7 1.71 x 10-6 4.12 x 10-' -- -- - Chloroform . 4.63 x 10-7 2.32 x 10-7 -- 0.008 0.0004 0.01 Total 1.48 x 10 4.07 x 10 1.62 x 10 0.434 0.018 0.01 5.3.1 Uncertainties Three major types of uncertainties should be considered when reviewing the results of the exposure assessment: 1. uncertainties associated with predicting future land use, 2. uncertainties associated with estimating constituent concentrations at receptor locations, and 3. uncertainties associated with assumptions used in the exposure models. For the purposes of this risk assessment, the most conservative land -use scenario (residential) was evaluated in addition to the one more realistic scenario (future construction worker). The probability that residences would be built in this area covered by large power transformers and transmission lines is implausible yet was included here as a worst -case bounding of the risk. In addition, the possibility that the shallow aquifer underlying the site would be used for drinking water is extremely low. Physiological values (e.g., body weight, inhalation rates) and behavioral values (e.g., average time spent in one place, amount of groundwater ingested) used to model the RME are a combination of average and upper -bound levels taken from reliable regulatory sources (e.g., USEPA). The use of upper -bound estimates will tend to overestimate exposure for the RME; therefore, the range of potential risks is likely to be greater than the actual risks. This approach provides conservative, health -protective values for the risk assessment. The toxicological parameters used to quantify potential risk to a receptor include cancer slope factors (CSFs) and reference doses (R.fDs). These values are often derived from laboratory animal studies. The overriding uncertainties associated with the use of laboratory animal studies are as follows: 5-5 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\final\Final SWMU69 CMS.doc • the extrapolation of toxic effects observed at the high dose necessary to conduct - animal studies to effects that might occur at the much lower, environmentally relevant doses; • and the extrapolation from toxic effects in animals to toxic effects in man (i.e., the potential for animal responses to differ from responses of man). USEPA has derived CSFs using a weight -of -evidence approach from studies in the scientific literature. The CSFs represent the upper 95 percent confidence limits on the slope of the dose response curve for carcinogenic responses. Because CSFs represent the near upper limits of the slope of the line, the use of the CSF is more likely to overestimate the actual risk than to underestimate it. The risk characterization evaluates the potential risks associated with exposure to numerous constituents via multiple pathways. There is uncertainty associated with exposure to constituent mixtures because constituents may have synergistic or antagonistic effects on other constituents. For the purposes of this risk assessment, it was assumed that all constituents have additive toxicity and that the potential health effects would be equal to the sum of each of the individual constituent actions for constituents that act upon the same target organ. This may result in the overestimation or underestimation of certain risks. In general, sources of uncertainty may be categorized into site -specific factors (e.g., variability in analytical data, modeling results, and exposure parameter assumptions) and toxicity factors. The use of conservative assumptions in the risk assessment is believed to result in an overestimation of risk. Actual site risks are likely to be lower than the estimates presented here. 5.4 REMEDIAL GOAL OPTIONS Risk -based Remedial Goal Options (RGOs) have been developed for the groundwater pathway for residential land use based on the risk levels calculated from the 2002 analytical data collected during the Supplemental RFI. RGOs were calculated for the three COCs in the groundwater that were identified during the Supplemental RFI. COCs are the most significant contaminants in an exposure scenario that exceed an excess cancer risk level of 1.0 x 1076 or a hazard quotient (HQ) of 1.0. Three of the four COPCs were retained as COCs for development of RGOs. The ILCR for chloroform was below • both the 10-6 risk level for all receptors, and the maximum detected concentrations (MDCs) (5.6 µg/L) was below the NC 2L standard for chloroform (70 µg/L). Therefore, chloroform is. not considered to present a significant risk to groundwater receptors and is eliminated from further evaluation. The RGOs are guidelines and are not meant to establish cleanup criteria, but are a summary of cleanup goals that provides the risk manager with a range of risk:related levels to use as a basis for developing a remediation or risk management strategy. RGOs have been calculated for COCs based on a target- risk level of 1.0 x 10-6, 1.0 x 10-5, and 1.0 x 10-4 for carcinogens; and a total HI level of 0.1, 1.0, and 3.0 for the non -carcinogens,. respectively. Table 5.2 presents a summary of the RGOs for a future residential scenario. The RGOs were calculated using the simplified equation described in the USEPA Region 4 (1996b): 5-6 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc Table 5.2�� Summary of Risk -Based Remediation Goal Options (RGOs) for Groundwater Fort Bragg, North Carolina Chemicals of Concern Range Detected (Ftg/L) RGOs RGOs MCL (µg/L) NC 2L (µg/L) Cancer Risk Levels (µg/L) Non -Cancer Risk Levels (µg/L) Min Max 1E-6 1E-5 1E-4 HQ=0.1 I HQ=1 HQ=3 Adult Resident Tetrachloroethene 0.42J 32 0.2 2 16 56 5,570 16,710 5 0.7 Trichloroethene 0.36J -91 5.9 59 592 70 660 198,000 5 2.8 1,1,2,2- Tetrachloroethane 0.40J 1.8 0.3 3 30 NA NA NA -- b/ 0.17 Child Resident Tetrachloroethene 0.42J 32 0.5 5 50 24 240 720 5 0.7 Trichloroethene 0.36J 91 6.2 62 620 3 28 80 5 2.8 Installation Worker Tetrachloroethene 0.42J 32 1.0 10 50 NA NA NA 5 0.7 Trichloroethene 0.36J 91 11 110 1,800 NA NA NA 5 2.8 ' NA= not applicable. b/ = no data available. RGO (chemical i) = EPC (chemical i) x Target Risk/Calculated Risk (chemical i). The MDCs for all three COCs are below the USEPA MCLs. The MCLs are promulgated by the National Primary Drinking Water Regulations and are legally enforceable standards meant to protect drinking water quality. USEPA Region 4 uses a total incremental risk level of between 1 x 10-6 and a 1 x 10 as an "acceptable level' of risk and risks that exceed a 1 x 10-4 level as a "trigger" to require some remedial activity. RGOs are presented for each COC for those receptors that had an ILCR that was greater than 1 x 10-6. No receptor had an ILCR that exceeded 1 x 10-4 for any COC. Of the remaining chemicals of concern, the MDC of tetrachloroethene (32 µg/L) exceeds the RGO calculated at the 10-4 risk level for future adult residents (16 µg/L), the USEPA MCLs (5 µg/L) and the North Carolina 2L Groundwater Standard of 0.7 µg/L. The MDC for trichloroethene (91 µg/L) does not exceed the RGO calculated at the 10-4 risk level (620 µg/L) but does exceed the 10-5 risk level (62 µg/L for children and 59 for adult residents), the EPA MCL (5 µg/L) and the NC 2L Standard of 2.8 µg/L. The MDC for 1,1,2,2-TeCA (1.8 µg/L) does not exceed the 10-5 risk level for any receptor, but does exceed the NC 2L Standard of 0.17 jig/L. Recommended remediation goals are NC 2L standards. 5-7 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMSTna1\Fina1 SWMU69 CMS.doc SECTION 6 JUSTIFICATION AND IDENTIFICATION OF CORRECTIVE ACTION ALTERNATIVES The groundwater media at SWMU 69 remains the only media for which corrective action is warranted. Groundwater detections exceed the risk -based screening criteria and NC 2L standards. A human -health risk assessment for the groundwater at SWMU 69 found that there was no risk to any current receptors, as there is no current use of groundwater at this site for either residential or industrial purposes. Incremental lifetime risks were calculated for future residential receptors and industrial workers. Future carcinogenic risks were found within the 10-6 to 10-4 range of acceptable risk. Generally, risk levels that exceed the 10-4 level will trigger a remedial action (USEPA Region 4, 1996b). , North Carolina requires that groundwater be remediated to the NC 2L standards. PCE and TCE have been detected in the majority of the groundwater samples collected at SWMU 69, with random detections of 1,1,2,2-TeCA in a few samples. 1,1,2,2-TeCA was not detected in any samples during the October 2000 sampling event. Because there are exceedences of the North Carolina Groundwater Standards for the COCs in the groundwater at this site, corrective action is warranted. The objective .of the corrective action will be to prevent future human exposures to unacceptable levels of site COCs (PCE, TCE, and 1,1,2,2-TeCA) in the groundwater. Corrective action objectives are developed as guidelines in the selection and evaluation of remedial alternatives. Corrective measures objectives are designed to meet the requirements of five basic criteria established by the EPA. These are: 1) to protect human health and the environment; 2) attain clean up standards set by the implementing agency; 3) control the source of release to reduce or eliminate further releases; 4) comply with any applicable standards for management of wastes, and 5) other factors. 6.1 CORRECTIVE MEASURES OBJECTIVES Corrective action objectives have been developed for SWMU 69 based on the site related contaminants, physical conditions, identification of applicable, relevant and/or appropriate requirements (ARARs), and the baseline risk assessment. These objectives are to: • Prevent current human exposures to the chemicals of concern in the groundwater through the ingestion, inhalation and dermal pathways. Currently the groundwater pathway is incomplete as there are no drinking water wells within and around SWMU 69 indicating the potential risk to future residential receptors is low and within accepted levels. • Prevent future human exposure to unacceptable levels of chemicals of concern in the groundwater through the ingestion, inhalation and dermal pathways. 6-1 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc • Reduce the levels of COCs in the groundwater to meet the North Carolina 21, r, f� standards. . The selected corrective actions will be technologies that will reduce concentrations in the groundwater and achieve the best overall results with respect to such factors as effectiveness, implementability and cost. 6.2 IDENTIFICATION OF REMEDIAL LEVELS The North Carolina 21, groundwater standards are required by. NCDENR as the remedial levels for the groundwater for SWMU 69. The maximum detections of PCE, TCE, and 1,1,2,2-TeCA exceeded the North Carolina 2L groundwater standards. 6-2 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc SECTION 7 SCREENING OF CORRECTIVE ACTION ALTERNATIVES This section identifies corrective action process options/technologies applicable to groundwater at SWMU 69 and screens the process options/technologies with respect to effectiveness, implementability, and cost. The process options/technologies that are retained following the screening process are combined into site -wide corrective action alternatives that address various levels of protectiveness of human health and environment. The corrective action alternatives are then described and evaluated in more detail with respect to RCRA standards in accordance with EPA guidance (EPA 1994) consisting of protecting human health and the environment, attaining media cleanup standards, controlling the source of release, compliance with applicable standards, and other factors (long-term reliability and effectiveness, reduction in toxicity, mobility, or volume of wastes, implementability, and cost). Based on this evaluation, a site -wide alternative is selected for detailed conceptual design -and evaluation. 7.1 SCREENING CRITERIA Specific site conditions either favor or limit the use of a particular technology. If a technology could not easily be implemented or was thought to be ineffective, it was eliminated from further consideration. Descriptions of these criteria are,�sfoll6ws: Effectiveness. The effectiveness of a corrective action is measured by the degree to which it protects human health and the environment: The reduction of toxicity, mobility, and volume of contaminants is evaluated both as a goal in itself and as a means to measure the corrective action's ability to protect human health and the environment. Both short- and long-term aspects of each alternative's effectiveness are evaluated. Short-term effectiveness refers to the period during implementation and remedial construction. Risks posed by remedial activities to construction workers, equipment operators, and the public during site operations and transportation of contaminated materials to off -site facilities are evaluated. Long-term effectiveness provides a measure of the alternative's ability to protect human health and the environment in the future, after corrective action is complete. Imnlementability. The implementability criterion is used to evaluate the feasibility of constructing, operating, and maintaining the corrective action. The technical aspect of feasibility refers to the ability to reliably construct, operate, and meet regulations for the technology until the corrective action is complete. It includes long-term operation, maintenance, and monitoring considerations in the future, as well as availability of materials and accessibility of the site. The administrative aspect is assessed by evaluating the regulatory requirements to obtain approvals for the technology proposed. Availability and capacity of treatment, storage, and disposal facilities are also assessed where necessary. 7-1 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc Cost. At this level of corrective action development, alternatives are assessed based on order -of -magnitude costs. In general, costs are not used to compare treatment to non- treatment alternatives. Capital and operation/maintenance costs are considered in this section, as well as the potential for future corrective action costs. 7.2 IDENTIFICATION OF TECHNOLOGIES FOR GROUNDWATER Categories of remedial technologies were identified based on a review of literature, vendor information, performance data, applicability to the site contaminants, and the ability to meet remediation goals. Technologies considered to be potentially applicable to attaining the corrective action objectives were selected for further screening. Technologies have been grouped into general process categories. Descriptions of the general categories are provided below. No Action. The site will be maintained in its current condition, with no restricted accesses beyond the existing fencing and structures. Future use would be unrestricted. Institutional Action. Access to the site would be controlled. Environmental monitoring would be conducted to record changes in site contamination through time. Future use of the site would be controlled through the Base Master Plan (BMP). There would be no reduction in toxicity, mobility, or volume of contaminants except through natural attenuation. Groundwater long term monitoring (LTM) would be performed to document changes in COC concentrations and distribution through time. Monitored Natural Attenuation: Site contaminants would be permitted to degrade through natural biodegradation and physical/chemical processes. Environmental monitoring of contaminants and other biogeochemical indicators would be conducted to track the progress of attenuation processes. In Situ Treatment. Reactive compounds would be injected or emplaced into the subsurface soils and/or groundwater to degrade contaminant mass. In -situ treatment includes both aerobic and anaerobic degradation mechanisms. Groundwater Extraction and Treatment. Groundwater is pumped from the ground to a storage tank above ground and processed through a treatment system such as carbon adsorption to remove COCs. Treated water is then either disposed of through permitted discharge to surface water or permitted re -injection into the subsurface. 7-2 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc i SECTION 8 SELECTION OF' TECHNOLOGIES A no action alternative and four categories of corrective action process options/technologies were identified as applicable for chlorinated solvent contamination in groundwater at SWMU 69: (1) institutional controls: land- and groundwater -use restrictions and physical barriers, (2) monitored natural attenuation (MNA), (3) in -situ technologies (e.g., chemical oxidation, bioaugmentation, phytoremediation, etc.), and (4) ex -situ treatment technologies (i.e., pump and treat). The technologies were evaluated using the screening criteria of effectiveness, implementability, and cost. Results of the screening are summarized in Table 8.1. Monitoring is also discussed; monitoring would be a component of any alternative except the no action alternative. 8.1 NO ACTION The no action option provides a baseline against which other process options/technologies can be compared: Under this option, no further action would be taken to mitigate risks posed by groundwater at SWMU 69. Risks to human health and the environment would remain the same.. Groundwater at SWMU 69 is presently not used and no restrictions or controls would be placed on the use of groundwater. Future use of the groundwater is unlikely given the poor production characteristics ii the surf cial groundwater and the presence of a large electrical substation and associated high voltage power lines in the area; however, there are no measures in place to prevent future use. Contaminants in groundwater would continue to migrate downgradient from the SWMU 69 area, potentially entering the unnamed tributaries to Young Lake where there is the potential for risk to human health and the environment. Under the "no action" alternative, groundwater monitoring would not be performed to assess the future levels of contamination or potential contaminant migration. Groundwater and potentially surface water contamination 'would continue to exist at unknown levels. No cost would be associated with the selection of this alternative. The acceptability of the no action option is judged in relation to the assessment of known site risks and by comparison with other corrective action technologies. The "no action" alternative is not considered to be a viable option because it provides no reliable or effective method for protecting human health or the environment. The no action, option has therefore been eliminated from further evaluation. 8.2 INSTITUTIONAL CONTROLS Institutional controls are actions taken to restrict access to contaminated areas or media through the establishment of land- or groundwater -use restrictions or by construction of physical barriers. Land- and groundwater -use restrictions include those implemented through the BMP. Groundwater -use restrictions would be placed on the groundwater preventing its use for drinking water or irrigation. Land- and groundwater- SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc ALTERNATIVE PROCESS DESCRIPTION RETAINED?. No Action None.. No actions .would be taken under, No this Alternative. Institutional Access and Implementation of groundwater -Not as a: stand . Controls Use and land usc, restrictions to alone . . Restrictions - control future use of site alternative Monitored Natural Groundwater Implementation of monitoring:.to, Not as 'a -stand Attenuation (NINA) 'Monitoring document changes: in:CO,C: alone' concentrations ..And.distribution . alternative In. Situ Treatment In Situ -Introduced compounds 'Yes Chemical chemically oxidize organic Oxidation . contaminants. Enhanced Introduced carbon ,substrate acts Yes Anaerobic as food source for natural Biorerriediati bacteria, altering geochemical on environment and resulting; in. anaerobic reductive dechlorination'.of chlorinated' contaminants. Permeable Trench would be -excavated No Reactive . through. the water. table.to the Barrier .. contaminated zones, Arid then 'backf lled with a reactive medium such as Fe° to oxidize. the contaminant passively as the groundwater flows, through the: . system. Ilie. same: medium. could also.be injected to.form a reactive barrier. Ex=Situ Treatment Pump and Groundwater is'. extracted and No . Treat.. treated on thesurface to,remove contaminants, then discharged to groundwater or surface water. use restrictions would be documented and implemented at Fort Bragg through the BUT. Currently, SWMU 69 is part of a federal installation and is expected to be retained by the federal government for the indefinite future. As such, land- and groundwater -use restrictions would be implemented as specified in the facility BMP. Land -use restrictions and would provide an effective, readily implementable, and cost- effective method for reducing the potential for human exposure to contaminants at the site. Groundwater -use restrictions would ..be effective at preventing exposure to the contaminants in groundwater. Costs related to institutional controls would be minimal and implementation could be immediate. However, land use restrictions would not reduce the toxicity, mobility, or mass of contaminants, nor reduce the potential for the migration of contaminants from the site. Therefore, institutional controls will not be considered as a stand-alone technology but will be combined with other more active process options/technologies to, ensure their protectiveness during the corrective action period. 8.3 MONITORED NATURAL ATTENUATION Natural attenuation or intrinsic remediation is defined as the measurable reduction in the concentration and mass of a substance in groundwater due to naturally occurring physical, chemical, and biological processes without human intervention. These processes include, but are not limited to, dispersion, diffusion, volatilization, sorption, retardation, and biodegradation. Many organic compounds are degraded in the subsurface environment by both biological and abiotic mechanisms. However, biological mechanisms tend to dominate in most groundwater systems and, therefore, are the primary destructive natural attenuation mechanism. The primary process for natural biodegradation of the more highly chlorinated species is biologically mediated sequential anaerobic reductive dechlorination: ,;This involves the microbial transformations of chlorinated solvents under anaerobic conditions (without oxygen) that convert highly chlorinated solvent species to less chlorinated solvent species by replacing chlorine atoms with hydrogen atoms. The chlorinated ethene chain is sequentially dechlorinated from the parent compound PCE through TCE, cis-1,2-DCE, VC, to the reaction end product ethene. Reductive dechlorination only occurs under anaerobic conditions where dissolved oxygen is absent and where the groundwater ORP values are below zero. Secondary degradation processes that effect chlorinated solvents include aerobic cometabolism, abiotic degradation, and anaerobic oxidation. These processes are less common than reductive dechlorination, but have been demonstrated to be significant contributors to contaminant destruction on some sites. These processes may be occurring at SWMU 69, but have not -been documented. Non-destructive MNA mechanisms that will serve to reduce contaminant concentrations include dilution, dispersion, volatilization, and sorption. These non- destructive mechanisms occur at all contaminated sites and are established by monitoring contaminant concentrations over time to document decreasing contaminant concentration trends. The MNA remedial option will not be retained as a stand alone option for further evaluation because it is unlikely that the non-destructive MNA mechanisms alone will be sufficient to reduce contaminant concentrations at SWMU 69 within a reasonable time 8-3 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc frame. In addition, MNA alone is not protective of potential receptors. However, MNA could be employed in combination with institutional controls (Section 8.2) to ensure the protection of human health and the environment over the typically longer implementation times required to meet remedial levels. In addition, MNA could be combined with more active technologies to meet the RROs for the site in a more reasonable timeframe. MNA is retained for further consideration in conjunction with ICs and more active remedial approaches only. 8.4 IN -SITU TREATMENT TECHNOLOGIES In -situ treatment technologies generally involve the injection or emplacement of reactive media designed to destroy contaminant mass in the subsurface without removing any contaminated media (e.g., soil, soil vapor, or groundwater). There are three general categories of in -situ contaminant destruction mechanisms or configuration approaches that can be employed to destroy contaminants present in the SWMU 69 plume (PCE, TCE, and 1,1,2,2-PCA); in=situ chemical oxidation (ISCO), enhanced bioremediation; and permeable reactive barriers. 8.4.1 ISCO ISCO involves the injection of an oxidiz_na agent, and potentially a catalyst, to oxidize tcrra e e c lormated solvents in groundwater. The nrimary chemical oxidation agents are hvdroaen peroxide, vermanganate, ozone, and Fenton's reagentTM (hydrogen peroxide and iron). During the ISCO process the oxidant chemicals react with the contaminant producing innocuous substances such as carbon dioxide, water, and inorganic chloride. Classes of chemicals that are amenable to treatment by ISCO include benzene, toluene, ethylbenzene, and xylenes (BTEX), chlorinated solvents, polyaromatic - hydrocarbons, and many other organic compounds. The chemical oxidant is typically injected through a series of injection wells or temporary points established on a grid basis throughout the impacted area. ISCO relies on contact based chemical reactions and is effective only if the oxidant can be emplaced in such a way that the entire contaminated volume is blanketed with the oxidant. Any distribution gaps or areas of low permeability will result in contaminant concentration rebound immediately after the completion of the ISCO injection. Chemical oxidation typically is more appropriate for contaminant plumes with higher contaminant concentrations and not the relatively large low concentrated contaminant plume at SWMU. 69. Multiple oxidant injections are typically required to destroy sufficient contaminant mass to reach remedial goals. ISCO is retained for further evaluation as a potential remedial option for the SWMU 69 plume. 8.4.2 Enhanced Anaerobic Bioremediation The second in -situ destruction mechanism t sideration fora lication at U 69 is enhanced anaerobic bioremediation (enhanced anaerobic reductive ,hlorma ion . Reductive dechlorination is the most prominent mechanism by which chlorinated VL)L;s are biologically aegradea ana taxes place unaer anaerobic (no oxygen) conditions. The degradation pathways for 1,1,2,2-PCA; PCE; and TCE is presented in Ti:i�e 5 1. Anaerobic reductive dechlorination is a process in which anaerobic microorganisms substitute hydrogen for chlorine on the chlorinated solvent. This naturally occurring process can be enhanced or augmented by adding organic substrate that acts as a food source for the microbial population and a molecular hydrogen source 8-4 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\tina1\Fina1 SWMU69 CMS.doc to provide hydrogen necessary for reductive dechlorination. There are a number of 'J organic substrates that have been injected into the subsurface at chlorinated solvent sites to facilitate reductive dechlorination and their selection is based on site -specific conditions. These include both liquids (sodium lactate, molasses, and vegetable oil) and solids or semi -solids (HRCTM and chitin). Site -specific geochemistry conditions determine whether reductive dechlorination can be effectively initiated and maintained in the subsurface. Elevated DO concentrations and positive ORP conditions were measured during groundwater sampling at SWMU 69, indicating an aerobic and nonreducing subsurface environment at SWMU 69. These natural conditions are not conducive to anaerobic reductive dechlorination; however, they can be overcome by adding sufficient organic substrate. The relatively high groundwater flow rates (-100 ft/year) may complicate the maintenance of anaerobic conditions. The nitrate and sulfate concentrations in groundwater ranged from 0.3 to 3.3 mg/L and less than 1.0 to 9.6 mg/L, respectively. Low to moderate nitrate and sulfate concentrations greater than 1.0 and 20 mg/L, respectively, may compete with the reductive pathway but will not preclude the initiation and maintenance of anaerobic conditions necessary for reductive dechlorination (AFCEE 2004). In addition, total iron concentrations in groundwater ranged from less than 0.2 to 17.0 mg/L, indicating that iron is also present at low to moderate concentrations at SWMU 69. Moderate concentrations of iron represent an inefficiency to anaerobic dechlorination similar to other competing electron acceptors (AFCEE 2004). The low to moderate concentrations of competing electron acceptors present at SWMU 69 do not preclude the implementation of anaerobic reductive dechlorination at SWMU 69. However, they will put an additional demand on the quantity of electron donors that are required to obtain and maintain the proper environment for. anaerobic reductive dechlorination to be successful. Analysis of contaminant coiieentrations in the source area indicate that reductive dechlorination has not occurred on site in the past (Section 5.0) due to naturally occurring aerobic conditions at SWMU 69. While naturally occurring aerobic conditions will likely delay the onset of complete reductive dechlorination and is thus. a negative factor, the presence of naturally aerobic conditions is a positive factor as well in that any VC produced through reductive dechlorination will not migrate beyond the treatment area because VC is degraded very rapidly under aerobic conditions. Given the large plume size with relatively low concentrations of chlorinated solvent contaminants and the low to moderate concentrations of competing electron receptors SWMU 69 is a good candidate for application of anaerobic reductive dechlorination for plume treatment. A combination of soluble (e.g., high fructose corn syrup) and slow release (e.g., vegetable oil) carbon substrates is particularly well -suited for the SWMU 69 source area. The soluble substrate will begin to biodegrade immediately, driving the groundwater geochemistry into anaerobic conditions. The slow release substrate will help maintain these conditions over the long term. A pH amendment product such as sodium bicarbonate will also be added to maintain neutral pH conditions, optimal for chlorinated solvent biodegradation. Some of the injection points can be completed. as small diameter wells so that supplemental carbon substrate, pH amendment, and if necessary, bioaugmentation culture can be added. 8-5 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\final\Final SWMU69 CMS.doc Generally, microorganisms capable of reductive dechlorination are ubiquitous in thef environment, but may take time to generate a population sufficient to provide significant biodegradation. If this process is slow in developing, bioaugmentation can accelerate the process. In situ enhanced anaerobic bioremediation is retained for further evaluation as a potential remedial option for the SWMU 69 plume. 8.4.3 Permeable Reactive Barriers Permeable reactive barriers (PRBs) using zero-valent iron or other reactive media are a passive in -situ treatment technology that has been demonstrated to be successful in treating chlorinated solvents contamination in groundwater. Permeable reactive barriers are trenches excavated perpendicular to the groundwater flow path and backfilled with a reactive medium. The reactive barrier can be designed and constructed to be permanently left in -place or can consist of cassettes of treatment medium that can be periodically replaced. As the contaminated groundwater flows through the wall, the contaminants are removed by physical and chemical processes including precipitation, sorption, oxidation/reduction, fixation, and degradation. Several methods have been developed for construction of permeable reactive walls to as deep as 100 ft BGS; however, typical construction techniques are applicable to shallow emplacements less than 35 ft in depth. In the simplest case, a trench of the appropriate width can be excavated by a backhoe, tracked excavator, trencher, or similar equipment to intercept the flow of the contaminated groundwater. The contaminant plume that has been defined at SWIVIU 69 is a relatively large diffuse plume with several hotspots that are interpreted to be areas where small contaminant spills may have taken place. If a PRB were to be installed at SWMU 69, the appropriate installation location would be downgradient of the defined hot spots. The topography in the area downgradient of the hot spots consists of relatively steep banks and wetlands which are inaccessible to trenching equipment. In addition, the construction of a PRB in this area would result in significant impacts to the wetlands and associated sensitive habitats. Thus, the PRB alternative has been eliminated for further consideration at SWMU 69. 8.5 EX -SITU TREATMENT TECHNOLOGIES Pump -and -treat technologies consist of the installation of a series of extraction wells or subsurface drains in the area of the plume that are typically manifolded together and connected to a common treatment system(s). Groundwater is pumped/extracted from the aquifer to a treatment system. The treatment processes are specific to the contaminants in the groundwater. For the COCs at SWMU 69, various treatment systems ranging from ex -situ air stripping to ' activated carbon are applicable. Discharge of any treated groundwater from the treatment system would require a National Pollutant Discharge Elimination System permit to discharge the treated water. Site -wide pump -and -treat technologies were eliminated because the large size of the contaminated groundwater plume (more than 36 acres) and the relatively diffuse nature of the SWMU 69 contaminant plume. The large plume area would require an extensive number of extraction wells manifolded together and would generate large quantities of water requiring treatment. At the same time the extraction wells needed to capture the plume would only extract groundwater containing low contaminant concentrations. r S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc Thus, the cost per unit mass of contaminant removed would be extremely high. In - addition, a large part of the plume is inaccessible due to the presence of the electrical substation built on site and the presence of the wetland/marsh area located at the confluence of the two unnamed Young Lake tributaries. 8.6 MONITORING Monitoring of groundwater and potentially surface water is required to ensure the protection of human health and the enviroriinent and to evaluate the performance of an implemented corrective action. The monitoring requirements (sample schedule, number of samples, locations, etc.) would be specific for the selected corrective action alternative. The description and purpose of the monitoring of each media will be discussed in the following sections. Groundwater monitoring would be performed in selected monitoring wells at SWMU 69 to evaluate the performance of an implemented corrective action. The groundwater would be sampled using low -flow techniques to reduce the impact of turbidity on the groundwater samples. At a minimum, the groundwater samples would be analyzed for VOCs to evaluate the concentrations of identified contaminants and potential degradation products in groundwater. In addition, field parameters such as turbidity, DO, temperature, Redox, and pH would be measured from each well where groundwater samples were collected. Water' levels would be collected at the monitoring wells to develop groundwater potentiometric maps. Additional analysis may be performed on groundwater for the implementation of specific alternatives. For example, natural attenuation parameters would be collected for alternatives in which MNA was part of the alternative, - - or geochemistry (nitrate, sulfate, TOC, etc.) samples may be collected for in -situ treatment alternatives. Specific sample requirements for groundwater will be discussed as part of each alternative. Surface water samples may be collected to evaluate potential contaminant migration from groundwater to the unnamed tributaries to Young Lake. At a minimum, the surface water samples would be analyzed for the COCs in groundwater migrating from SWMU 69 (PCE, TCE, and 1,1,2,2-PCA). Specific sample requirements for surface water will be discussed as part of each site -wide alternative. 8-7 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc SECTION 9 EVALUATION OF CORRECTfVE ACTION ALTERNATIVES FOR GROUNDWATER Following the OSWER 1994 RCRA Corrective Action Plan guidance, SWMU 69 does not present a significant risk because (1) it has only one media of concern (groundwater), (2) there is no source area remaining, and (3) levels of contamination in the groundwater are relatively low. SWMU 69 also does not present a current risk to human health or the environment. For these reasons, it is. appropriate to perform a streamlined or limited remedial action for SWMU 69. As such, this corrective measures study will focus on in situ remediation technologies that have been proven successful in reducing low levels of chlorinated hydrocarbons in the past at other sites. These .in -situ technologies. are combined and developed_ into corrective action alternatives_, in this section. Five corrective action alternatives have been identified that would meet the remedial response objectives of protecting human health and reducing groundwater concentrations of the COCs to acceptable levels. These alternatives will be evaluated and further assessed in this section. Costs estimated are based only on the conceptual designs and are meant to be used only for the comparisons of the corrective action alternatives.,. 9.1 ALTERNATIVE 1- INSTITUTIONAL CONTROLS WITH MONITORED NATURAL ATTENUATION Under Alternative 1, no active remedial technology would be applied to reduce the volume or concentrations of the COCs at SWMU 69. Currently there is no risk to human health from the groundwater as it is not used for a source of.potable water. Potential risks to human health in the future would be managed by restricting groundwater and land use in the SWMU 69 area. These restrictions would prohibit the installation of potable water wells in the surficial aquifer by amending the Fort Bragg Master Plan. A long-term environmental sampling program would be required to monitor the changes in contaminant concentrations and distribution over time. Approximately fourteen wells (including one new well) and one surface water sampling location would be monitored annually for VOCs and natural attenuation parameters and a Corrective Action Plan Progress Report would be generated annually. The progress report would also document the condition of the site monitoring wells, repairs that are needed, and the location of the land use controls. The capital cost for alternative one would consist of the preparation of a site decision document and the installation of one new monitoring well north of Butner Road (Figure 9.1). It is estimated that the preparation of the record of decision and the installation of the new well will cost approximately $110,000. The only other possible costs associated with alternative one would include the installation of signage associated with the land use i i - 9-1 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU=69\CMS\fina1\Fina1 SWMU69 CMS.doc controls. The capitol costs associated with the land use control signage would be t negligible. Operations and maintenance (O&M) costs for alternative one for a 60-year period are estimated to be approximately $743,000.00. The unit rates that were used to develop this estimate are drawn from the previous version of the SWMU-69 CMS (USACE, 2006). O&M costs include sample collection, data validation, and annual or biannual reporting as appropriate. It is assumed that groundwater sampling would be conducted on an annual (1 event per year) frequency during years 1 through 4. Following year 4 it is assumed that sufficient data will have been collected to demonstrate that the SWW 69 plume is stable and that COC concentration trends in the plume hot spots are also stable or downward. If the plume can be demonstrated to be stable or shrinking, then the sampling frequency for the plume interior wells could be reduced to biennial (one every two years) while the plume sentry wells would remain on an annual sampling schedule. By year 11 the SWMU 69 plume is expected to be shrinking and COC concentrations are expected to be decreasing. Thus, it is assumed that the entire SWMU 69 monitoring well network could be moved to a biennial schedule. The total cost for Alternative 1 would be approximately $853,000.00. Detailed costs for this alternative are presented in Table 9. L Land use restrictions and groundwater monitoring would continue until COC concentrations declined below the NC 2L standards. 9.2 ALTERNATIVE 2 —INSTITUTIONAL CONTROLS AND IN SITU ORGANIC SUBSTRATE ADDITION IN 5 TREATMENT AREAS This alternative would consist of injecting organic substrate in a series of direct push -� boreholes across the flow path of the plume, allowing the groundwater to move through the injection zone. The contaminants would be degraded in situ through a series of -` chemical and biological reactions. The organic substrate would likely consist of a mixture of slowly soluble vegetable oil and soluble fructose or sodium lactate. Naturally occurring anaerobic or facultative microbes would metabolize the substrates, producing dissolved hydrogen necessary for reductive dechlorination. The hydrogen would be used by the microbes to dechlorinate the TCE and PCE. Because of the low concentrations of COCs and competing electron acceptors and the hydrologic characteristics of the aquifer, the vegetable oil substrate is expected to supply organic carbon and hydrogen for a period of 3 to 5 years. The length and width of the groundwater plume at SWMU 69 occupies a large, widespread area. Because of the large size of the plume and the relatively low contaminant concentrations in most areas, it would not be cost effective to treat the entire area of the plume. Instead, five areas within and around SWMU 69 have been identified in which detected concentrations of COCs have exceeded the NC 2L standards for the majority of the detections reported in the past. Figure 9.1 depicts the locations of these five zones. Organic substrate would be applied within these zones in a grid pattern. The total area within the five injection zones is approximately 2,400,000 square feet (ftz). COCs in the remaining plume area would be attenuated through natural attenuation mechanisms. Potential risks to human health in the future would be managed by restricting groundwater and land use in the SWMU 69 area. These restrictions would prohibit the installation of potable water wells in the surficial aquifer by amending the Fort Bragg BMP. A long-term environmental sampling program would be required to rN SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc 9-j orally left blank Table 9.1 Summary of Cost Comparisons for Corrective Action Alternatives Fort Bragg, North Carolina Alternative Alternative 1 Institutional Controls and Monitored Natural Attenuation Alternative 2 Institutional Controls and In Situ Organic Substrate Addition -in 5 treatment areas Alternative 3 Institutional Controls and In.Situ Organic Substrate Addition - Hot Spots Only Alternative 4 Institutional Controls with In Situ Chemical Oxidation Using Sodium Permanganate in 5 Treatment Areas Alternative 5 - Institutional Controls with In Situ Chemical Oxidation Using Sodium Permanganate - Hot Spots only Remedial Action Installation Record of Decision and Implementation Plan Preparation $100,000.00 $100,000.00 $100,000.00 $100,000.00 $100,000.00 Pilot Test to Demonstrate Technology Effectiveness $0.00 $120,000.00 $120,000.00 $120,000.00 $120,000.00 Remediation Construction & active operations) $10,000.00 $280,000.00 $87,500.00 $1,300,000.00 $357,500.00 Substrate Product* na $146,000 ai $37,660 b/ $200,000 a' $55,000 b/ Bioaugmentation Contingency na $125,000.00 $58,300.00 na na Second Injection Contingency na $213,000.00 $65,400.00 na na Remedial Action Reporting na $25,000.00 $25,000.00 $25,000.00 $25,000.00 Remedial.Action Installation Subtotal $110,000.00 $1,009,000.00 $493,860.00 $2,845,000.00 $657,500.00 Monitoring (3 event consisting of sampling at 12 wells and reporting) Subtotal for each groundwater monitoring event $22,000.00 $22,000.00 $22,000.00 $22,000.00 $22,000.00 Total monitoring cost Year 1 $22,000.00 $44,000.00 $44,000.00 $44,000.00 dl $44,000.00 Total monitoring cost years 2 and 3 `/ $44,000.00 $44,000.00 $44,000.00 $44,000.00 $44,000.00 Total monitoring cost years 4 through 10 $105,000.00 $105,000.00 $105,000.00 $105,000.00 $105,000.00 Total monitoring cost years 11 through 60 v $550,000.00 $220,000.00 e' $220,000.00 $220,000.00 x/ $220,000.00 s/ Total Cost for Application $853,000.00 $1,421,000.00 $906,860.00 $3,258,000.00 $1,070,500.00 Cost estimates for full scale remediation normalized to cover a 2,400,000 sq. ft. area. b/ Cost estimates, for hot spot treatment normalized to include 5 - 50 x 50 sq. st. areas. Costs assume an annual sampling schedule: a/ Costs assume a semi-annual sampling schedule. e/ Costs assume that the sampling frequency for plume core wells will be reduced to biannual (once every two years) while sentinal wells will remain on an annual frequency. f/ It is assumed that the sampling frequency for all site wells will be reduced to a biannual (once every two years) sampling schedule. rl It is estimated that the application of the active remedial alternatives will reduce the time required to reach NC 2L standards in groundwater by approximately 40 years. 9-5 monitor changes in contaminant concentrations and distribution over time. Approximately fourteen wells (including one new well) and two surface water sampling locations would be monitored annually for VOCs and natural attenuation parameters and a Corrective Action Plan Progress Report would be generated periodially. The progress report would also document the condition of the site monitoring wells, repairs that are needed, and the location of the land use controls. The active remedial processes presented in this alternative will serve to reduce the amount of time required to reach NC 2L standards within_ the SWMU 69 plume extent, thereby reducing the monitoring time period and time that land use controls (LUCs) would be in place. The organic substrate would be delivered to the subsurface by direct push injection though readily available equipment. The organic substrate would be emulsified with water and pumped under low pressure as a dilute vegetable oil -in -water emulsion into the formation through the zone of interest as the push rods are retracted. For SWMU 69, the volume of organic substrate estimated for all five zones is approximately 170,000 lbs. The organic substrate would be injected at a concentration of approximately 5 to 10 percent using 410 injection points. The injection points would be spaced over each area in rows that are 200 feet apart in the direction of the groundwater flow. Within each row, the injection points would be spaced 10 feet apart. The estimated time for application would be 200 days. The application of alternative 2 will require the removal of numerous trees, the construction of access routes through wetland areas, and the temporary shutdown of the -electrical substation in order to allow the safe operation of drilling rigs and injection equipment within the substation footprint. Semi-annual groundwater monitoring would be needed to evaluate the progress of the organic substrate induced degradation during the first year after substrate injection. After the first year monitoring events could be conducted annually during years 2 and 3. It is -_ expected that monitoring frequency could be reduced after the effectiveness of the treatment application has been demonstrated. It is assumed for costing purposes that during years 4 through 10 the monitoring frequency for plume core wells will be reduced to biennial and that the site sentinel wells would remain on an annual frequency to ensure that the contaminant plume remains stable. Following year 10 the majority of the contaminant mass associated with SWMU 69 will be destroyed and COC concentrations will be nearing NC 2L standards. Refer to Appendix C for performance data supporting the 10-year estimate. It is assumed for costing purposes that the monitoring frequency for all wells on site will be reduced to biennial. Many monitoring wells that currently have groundwater COC concentrations above NC 2L standards will likely,be below standards by year 10 and these "clean" wells could be removed from the sampling program. However, all monitoring wells are retained to yield a conservative cost estimate. Groundwater parameters to be monitored would include VOCs to evaluate the reduction in COCs, field parameters to evaluate the change in oxidation-reduction potential and electron donor parameters such as total organic carbon and metabolic acids to evaluate the effectiveness and longevity of the organic substrate. Groundwater elevations should be measured in all wells and piezometers (28 total) once a year to provide updated groundwater elevation data. A baseline groundwater monitoring event will be required prior to injection to establish pre -injection contaminant and geochemical conditions. The application areas would be refined based on the results of the baseline sampling event. After an initial period of 6 months, the first performance monitoring event should be conducted. If it is 9-6 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc demonstrated that the organic substrate has been effective in changing the subsurface J conditions from an aerobic environment to an anaerobic environment, then a commercially available microbial culture containing mixture of microbes known to be capable of completely dechlorinating TCE would be considered for injection into the subsurface to stimulate more rapid contaminant destruction rates. The bioaugmentation step is considered a potential contingency that may be deployed in the event that this remedial action is not working as rapidly as expected. However, for costing purposes it is assumed that the, bioaugmentation contingency will be deployed. Microbial bioaugmentation products are readily available through commercial vendors. An additional application of organic substrate might be necessary in some areas where the substrate becomes depleted before COC concentrations reach remedial goals. The sampling results obtained will indicate which areas might need a supplemental injection. Institutional controls prohibiting the installation of drinking water wells within the plume should be instituted until desired remediation goals are met. Estimated capital costs for well installation and organic substrate injection are $1,009,000.00. This installation cost includes funds to conduct a technology demonstration pilot test to ensure that the organic substrate addition technology is effective at reaching NC 2L standards at SWMU 69. O&M costs -for Alternative 2 for a 20-year period are estimated to be approximately $413,000.00:� It is assumed, based on technology performance at other sites with similar characteristics, that the injection of organic substrate will reduce the time required to reach NC 2L standards at SWMU 69 by approximately 65 percent (40 years) (appendix Q. The unit rates that were used to develop .this estimate are drawn from the previous version of the SWMU-69 CMS (USACE, 2006). O&M costs include sample collection; data validation, and annual or biennial reporting as appropriate. ,It Js -assumed that groundwater sampling would be conducted on a semi-annual (2 events per year) frequency during the first year following substrate injection and that the monitoring frequency would be reduced to annual for years 2 through 4. Following year 4 it is assumed that sufficient data will have been collected to demonstrate that the SWMU 69 plume is stable and that COC concentration trends in the plume hot spots are also stable or decreasing. If the plume can be demonstrated to be stable or shrinking, the sampling frequency for the plume interior wells could be reduced to biennial while the plume sentry wells would remain on an annual sampling schedule. By year 11 the SWMU 69 plume is expected to be shrinking and COC concentrations are expected to be decreasing. Thus, it is assumed that the entire SWMU 69 monitoring well network could be moved'to a biennial schedule. The total cost for Alternative 2 would be approximately $1,422,000.00. Detailed costs for this alternative are presented in Table 9.1. Land use restrictions and groundwater monitoring would continue until COC concentrations declined below the NC 2L standards. 9.3 ALTERNATIVE 3 - INSTITUTIONAL CONTROLS AND IN SITU ORGANIC SUBSTRATE ADDITION - HOT SPOTS ONLY This alternative would also consist of injecting organic substrate (vegetable oil and lactate or fructose) into the subsurface to induce biodegradation of the COCs. Areas with the highest detected concentration would be targeted for a more localized treatment. The goal would be to reduce the potential risk to future receptors by using institutional 9-7 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc controls and also reduce the overall concentrations within the groundwater plume by'� reducing those areas with the highest concentrations. Areas around five monitoring wells (69MW1, 69MW6, 69MW 18D, 69MW 19D, and 69MW21D) have been identified as hot spots based on historical ground -water monitoring data. Figure 9.2 shows the locations identified for "hot spot" treatment. Injection points would be placed in overlapping arcs installed immediately upgradient of the identified hot spots to ensure adequate coverage and substrate distribution. This would allow the groundwater flow to consistently supply the hot spot area with the substrate derived organic carbon and molecular hydrogen. COCs in the remaining plume area would be attenuated through natural attenuation mechanisms. Potential risks to human health in the future would be managed by restricting groundwater and land use in the SWMU 69 area. These restrictions would prohibit the installation of potable water wells in the surficial aquifer by amending the Fort Bragg Master Plan. A long-term environmental sampling program would be required to monitor the changes in contaminant concentrations and distribution over time. Approximately fourteen wells (including one new well) and two surface water sampling locations would be monitored annually for VOCs and natural attenuation parameters and a Corrective Action Progress Report would be generated annually. The progress report would also document the condition of the -site monitoring wells, repairs that are needed, and the location of the land use controls. The active remedial processes presented in this alternative will serve to reduce the amount of time required to reach NC 2L standards within the SWMU 69 plume extent, thereby reducing the monitoring time period and time that LUCs would be in place. A baseline groundwater monitoring event will be required prior to injection ' to r , establish pre -injection contaminant and geochemical conditions. The application areas ` may be refined based on the results of the baseline sampling event. Semi-annual groundwater monitoring would be needed to evaluate the progress of this alternative during the first year following substrate injection. After an initial period of 6 months, the first performance monitoring event should be conducted. If it is demonstrated that the organic substrate has been effective in changing the subsurface conditions from an aerobic environment to an anaerobic environment, then a commercially available microbial culture containing a mixture of microbes known to be capable of completely dechlorinating TCE may be considered for injection into the subsurface to stimulate more rapid contaminant destruction rates. The bioaugmentation step is considered- to be a potential contingency application that may be deployed in the event that this remedial action is not working as rapidly as desired. However, for costing purposes it is assumed that the bioaugmentation contingency will be deployed: An additional application of organic substrate may be necessary in some areas where the substrate becomes depleted before COC concentrations reach remedial goals. The sampling results obtained will indicate which areas might need a supplemental injection. Institutional controls prohibiting the installation of drinking water wells within the plume should be instituted and enforced until desired remediation goals are met. For costing purposes it is assumed that the second injection contingency will be required. 01-i S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\ftna1\Fina1 SWMU69 CMS.doc ` VTTAMW4 — v -VITAMW6 ` 1VTTAMW6 1� a VTTAMWI2 ^� - VTTAMW3 u 1VTTAMW8 VTTAMWI L AEHAV-2 VTTAM W 2 VTTAMW1OVTTAMW9 169MWB J AEHAV•3 '69MW7 r, j69MW5= - `{q �VTTAMW11-.- - Ni i O+ c 69MW2 ;E 69MW9, 1`69MW1i SWMU 69� Nj� 69MW22D. s69MW1 12MW9 69MW1 r 69MW22C 169MW3 - .69MW4 -69MW70 112MW4 -y tj 112MVV3 Legend — . Rail Roads_ Proposed Treat 169TMW23 ® Existing Growl( ------SCOTf ST- Proposed Nioni ® Surface Water', SWMU-69 Corrective Measures Study Stream FIVE PROPOSED TREATMENT AREAS (HOT SPOTS) FOR CORRECTIVE ACTION FT. BRAGG, NORTH CAROLINA ;v ? CHECKED BY D. GtlRihs FIGURE 1. Inch ec� �� DRAFTED BY CMBmah L FILE SWN11.69J1IU6mz0 - - DATE. I M7 9-9 ionally left blank Estimated capital costs for well installation and organic substrate injection in the 5 defined hot spots are $493,860.00. This installation cost includes funds to conduct a technology demonstration pilot test to ensure that the organic substrate addition technology is effective at reaching NC 2L standards at SWMU 69. O&M costs for Alternative 3 for a 20-year period are estimated to be approximately $413,000.00. It is assumed, based on technology performance at other sites with similar characteristics, that the injection of organic' substrate will reduce the time required to reach NC 2L standards at SWMU 69 by approximately 65 percent (40 years). The unit rates that were used to develop this estimate are drawn from the previous version of the SWMU-69 CMS (USACE, 2006). O&M costs include sample collection, data validation, and annual or biennial reporting as appropriate. A well network optimization study will be conducted periodically to determine the frequency of future events and which wells will be sampled during each event. For cost comparison purposes, it is assumed that groundwater sampling would be conducted on an semi-annual frequency during the first year following substrate injection and that the monitoring frequency would be reduced to annual for years 2 through 4. Following year 4 it is assumed that sufficient data will have been collected to demonstrate that the SWMU 69 plume is stable and that COC concentration trends in the plume hot spots are also stable or decreasing. If the plume can be demonstrated to be stable or shrinking, the sampling frequency for the plume interior wells _could be reduced to biennial while the plume. sentry wells would remain on an .annual sampling schedule. By year 11 the SWMU 69 plume is expected to be shrinking and COC concentrations are expected to be decreasing. Thus, it is assumed that the entire SWMU 69 monitoring well network could be moved to a biennial schedule. The total cost for Alternative 3 would be approximately $906,860. ,Detailed costs for this alternative are presented in Table 9.1. Land use restrictions and groundwater monitoring would continue until COC concentrations declined below the NC 2L standards. 9.4 ALTERNATIVE 4 - INSTITUTIONAL CONTROLS WITH IN SITU CHEMICAL OXIDATION USING SODIUM PERMANGANATE IN 5 TREATMENT AREAS Chemical oxidation is a direct reaction that results in destruction of the COCs in the subsurface. This alternative would consist of injecting sodium permanganate (NaMn04) solution into the subsurface within the same five zones discussed for Alternative 2. Sodium permanganate is an oxidizing agent that, when injected into the plume, reacts with the contaminants producing carbon dioxide, water, and inorganic chloride. Oxidizers will also consume naturally occurring organic matter in the subsurface. As many organic contaminants are sorbed to organic matter, this can result in a release of contaminants to the subsurface. This is generally considered a benefit for remediation purposes because more contamination is available for reaction; however, the design must account for both the sorbed and dissolved phase contamination. Based on available literature, the use of chemical oxidation would require less time to achieve a reduction in COC concentrations; however, there is -the possibility that Manganese Oxide (Mn02) could be precipitated, reducing the porosity in the subsurface. A bench test could also be obtained prior to decision making to determine contaminant mass reductions and oxidant efficiencies that can be used to refine the Work Plan. l 9-11 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc Sodium Permanganate would be injected into the subsurface in a grid pattern similar ` to that discussed in Alternative 2. The same areas identified in Figure 9.1 would be targeted. Sodium permanganate would be injected using a 40 percent solution. The number of injection points estimated for Alternative 4 is 1,200, using a total of 40,860 pounds of sodium permanganate. Estimated field time for application is 100 days. COCs in the remaining plume area would be attenuated through natural attenuation mechanisms. Potential risks to human health in the future would be managed by restricting groundwater and land use in the SWMU 69 area. These restrictions would prohibit the installation of potable water wellg' in the surficial aquifer by amending the Fort Bragg Master Plan. A long-term environmental sampling program would be required to monitor the changes in contaminant concentrations and distribution over time. Approximately fourteen wells (including one new well) and two surface water sampling locations would be monitored annually for VOCs and natural attenuation parameters and a Corrective Action Plan Progress Report would be generated periodically. The progress report would also document the condition of the site monitoring wells, repairs that are needed, and the location of the land use controls. The active remedial processes presented in this alternative will serve to reduce the amount of time required to reach NC 2L standards within the SWMU 69 plume extent, thereby reducing Ahe monitoring time period and time that LUCs would be in place. Chemical oxidation reactants (including sodium permanganate) are not handled as easily as the organic substrate -compound. Chemical oxidation reactants are more reactive, require careful handling when mixing and injecting under pressure; and represent more significant. health and safety concerns than organic substrates associated with alternative 3. The equipment used to mix and deliver the sodium permanganate is more specialized and a more limited number of venders are available for these applications. A baseline groundwater monitoring event will be required prior to injection to establish pre -injection contaminant and geochemical conditions. The application areas would be refined based on the results of the baseline sampling event. Semi-annual groundwater monitoring would be needed to evaluate the progress of the induced oxidation. Groundwater parameters to be monitored should include VOCs to evaluate the reduction in COCs, and field parameters to evaluate the change in oxidation-reduction potential and any mobilization of natural metals (in most cases, field and laboratory tests have found that mobilized metals are readily attenuated back to the original state). An initial baseline round should also be performed prior to injection. Permanganate can also be detected in monitoring wells by the purple color; concentrations in groundwater can be measured in the field using a field spectrophotometer. Estimated capital costs for well installation and chemical oxidation product injection in the 5 defined hot spots (Figure 9.1) are $2,845,000.00. This installation cost includes funds to conduct a technology demonstration pilot test to ensure that the chemical oxidation technology is effective at reaching NC 2L standards at SWMU 69. O&M costs for Alternative 4 for a 20-year period are estimated to be approximately $413,000.00. It is assumed that the injection of sodium permanganate will reduce the time required to reach NC 2L standards at SWMU 69 by approximately 65 percent (40 years). The unit rates that were used to develop this estimate are drawn from the previous version of the SWMU-69 CMS (USACE, 2006). O&M costs include sample _ 9-12 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc collection, data validation, and annual or biennial reporting as appropriate. It is assumed that groundwater sampling would be conducted on a semi-annual frequency during the first year following substrate injection and that the monitoring frequency would be reduced to annual for years 2 through 4. Following year 4 it is assumed that sufficient data will have been collected to demonstrate that the SWMU 69 plume is stable and that COC concentration trends in the plume hot spots are also stable or decreasing. If the plume can be demonstrated to be stable or shrinking, the sampling frequency for the plume interior wells could be reduced to ''biennial while the plume sentry wells would remain on an annual sampling schedule. By year 11 the SWMU 69 plume is expected to be shrinking and COC concentrations are expected to be decreasing. Thus, it is assumed that the entire SWMU 69 monitoring well network could be moved to a biennial schedule. The total cost for Alternative 4 would be approximately $3,258,000. Detailed costs for this alternative are presented in Table 9.1. Land use restrictions and groundwater monitoring would continue until COC concentrations declined below the NC 2L standards. 9.5 ALTERNATIVE 5 - INSTITUTIONAL CONTROLS WITH IN SITU CHEMICAL OXIDATION USING SODIUM PERMANGANATE - HOT SPOTS ONLY This alternative would consist of injecting the sodium permanganate solution in the same areas discussed in Alternative 3 (Figure 9.2). For each area, 4 to 5 injection points would .be needed for approximately 140 pounds of solution. Field efforts would take approximately two days for each hot spot application. Groundwater monitoring of selected wells for the same parameters discussed in Alternative 4 would be necessary. - The same health and safety concerns would apply. COCs in the remaining plume area would be attenuated through natural attenuation mechanisms. Potential risks to human health in the future would be managed by restricting groundwater and land use in the SWMU 69 area. - These restrictions would prohibit the installation of potable water wells in the surficial aquifer by amending the Fort Bragg Master Plan. A long-term environmental sampling program would be required to monitor the changes in contaminant concentrations and distribution over time. Approximately fourteen wells (including one new well) and one surface water sampling location would be monitored annually for VOCs and natural attenuation parameters and a Corrective Action Plan Progress Report would be generated annually. The progress report would also document the condition of the site monitoring wells, repairs that are needed, and the location of the land use controls. The active remedial processes presented in this alternative will serve to reduce the amount of time required to reach NC 2L standards within the SWMU 69 plume extent, thereby reducing the monitoring time period and time that LUCs would be in place. A baseline groundwater monitoring event will be required prior to injection to establish pre -injection contaminant and geochemical conditions. The application areas would be refined based on the results of the baseline sampling event. Semi-annual groundwater monitoring would be needed to evaluate the progress of the induced oxidation. Groundwater parameters to be monitored should include VOCs to evaluate the reduction in COCs, and field parameters to evaluate the change in oxidation-reduction potential and any mobilization of natural metals (in most cases, field and laboratory tests 9-13 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc have found that mobilized metals are readily attenuated back to the original state). An initial baseline round should also be performed prior to injection. Permanganate can also be detected in monitoring wells by the purple color; concentrations in groundwater can be measured in the field using a field spectrophotometer. Estimated capital costs for well installation and chemical oxidation product injection in the 5 defined hot spots (Figure 10.2) are $657,500.00. This installation cost includes funds to conduct a technology demonstration pilot test to ensure that the chemical oxidation technology is effective at reaching NC 2L standards at SWMU 69. O&M costs for Alternative 4 for a 20-year period are estimated to be approximately $413,000.00. It is assumed that the injection of sodium permanganate will reduce the time required to reach NC 2L standards at SWMU 69 by approximately 65 percent (40 years). The unit rates that were used to develop this estimate are drawn from the previous version of the SWMU-69 CMS (USACE, 2006). O&M costs include sample collection, data validation, and annual or biennial reporting as appropriate. It is assumed that groundwater sampling would be conducted on a semi-annual frequency during the first year following substrate injection and that the monitoring frequency would be reduced to annual for years 2 through 4. Following year 4 it is assumed that sufficient data will have been collected to demonstrate that the SWMU 69 plume is stable and that COC concentration trends in the plume hot spots are also stable or decreasing. If the plume can be demonstrated to be stable or shrinking, the sampling frequency for the plume interior wells could be reduced to biennial while the plume sentry wells would remain on an annual sampling schedule. By year 11 the SWMU 69 plume is expected to be shrinking and COC concentrations are expected to be decreasing. Thus, it is assumed that the entire SWMU 69 monitoring well network could be moved- to a biennial schedule. The total cost for alternative four would be approximately $1,070,500. Detailed costs for this alternative are presented in Table 9.1. Land use restrictions and groundwater monitoring would continue until COC concentrations declined below the NC 2L standards. 9-14 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\ftnal\Final SWMU69 CMS.doe SECTION 10 COMPARATIVE ANALYSIS OF ALTERNATIVES, CONCEPTUAL DESIGN, AND IMPLEMENTATION. PLAN This section presents a comparative analysis of the five remedial alternatives that were presented in detail in Section 9. A conceptual design and plan for implementation of the selected corrective action alternative is also presented in this section. A cost-effective corrective action has been selected that will adequately protect human health and the environment from groundwater and surface water contamination. 10.1 COMPARATIVE ANALYSIS OF CORRECTIVE ACTIONS A screening of remedial process options. and technologies applicable for chlorinated solvents in groundwater against site -specific conditions was performed in Sections 8 to identify applicable process options/technologies that would be effective and implementable at SWMU 69. The process options. passing the screening were combined to form five site -wide corrective action alternatives for detailed description and analysis (Section 9). The five corrective action alternatives selected provided a range of remedial options from primarily passive treatment technologies (Alternative 1: LUCs combined with MNA), to four active treatment alternatives (Alternative 2 through 5). This section presents a comparative analysis of the alternatives against RCRA criteria, which allows for the selection of an alternative that balances protection of human health, reduction in risks, and costs. The comparative analysis is summarized in Table 10.1. It should be noted that the final alternative developed for SWMU 69 may be revised by the risk managers as additional, site -specific information becomes available by either selecting a different combination of process options or by evaluating an additional previous process option that has been screened out. The following bullets summarize key points concerning SWMU 69 that were considered during the comparative analysis of alternatives and in the selection of the recommended alternative: • Low-level groundwater plume consisting of chlorinated solvents that encompasses approximately 36 acres. The primary COCs are chlorinated ethenes PCE and TCE and a chlorinated alkane, 1,1,2,2-TeCA. The maximum concentrations in groundwater ranged up to approximately 100 µg/L (PCE + TCE). • The groundwater plume has migrated northward from the SWMU 69 area toward Butner Road. • The source area has not been identified at SWMU 69. However, 6 small areas of elevated VOC concentrations have been identified and may represent separate small release areas. The six identified "hot spots" are targeted for active treatment under remedial alternatives 3 and 5. 10-1 SAES\RemedW45446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc Table 10.1 Corrective Action Alternatives Assessment Summary Fort Bragg, North Carolina Corrective Time to Feasibility Implementability Total Action Achieve Alternative Alternative Remediation Cost Goals 1. Institutional Longest, Fair to Poor; Good; simple and quick to Controls and dependent on The treatment implement. $853,000 MNA natural time required to conditions. reach NC 2L standards is uncertain. Alternative 2 - Mid -range; Fair to good; Poor. Presence of the Institutional depending on overall the electrical substation and $1,422,000 Controls and effectiveness plume has associated high voltage In Situ Organic of treatment relatively low lines as well as the Substrate for concentrations, presence of Addition in 5 Subsurface but a wetland/potential sensitive treatment areas conditions. widespread species habitats in the distribution. application areas makes this alternative difficult to implement. Alternative 3 - Mid -range; Fair to good; Good; Institutional depending on overall the All six hot spots are $906,860 Controls and effectiveness plume has accessible using existing In Situ Organic of treatment relatively low routes. Potential impacts Substrate for concentrations, to wetlands/sensitive Addition - Hot Subsurface but a species habitats is Spots Only conditions. widespread minimal. Injection distribution. products are commercially available from multiple vendors. Alternative 4 - Mid -range; Fair to good; Poor. Presence of the Institutional depending on overall the electrical substation and $3,258,000 Controls with effectiveness plume has associated high voltage In Situ of treatment relatively low lines as well as the Chemical for concentrations presence of Oxidation Subsurface but a wetland/potential sensitive using Sodium conditions. widespread species habitats in the Permanganate distribution application areas makes in 5 treatment this alternative difficult to areas implement. 10-2 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doe r .. ) Table 10.1 (Continued) Corrective Action Alternatives Assessment Summary Fort Bragg, North Carolina Corrective Action Alternative Time to Achieve Remediation Goals Feasibility Implementability Total Alternative Cost Alternative 5 - Mid -range; Fair to good; Good; Institutional depending on overall the All six hot spots are $1,070,500 Controls with effectiveness plume has accessible using existing In Situ of treatment relatively low routes. Potential impacts Chemical for concentrations, to wetlands/sensitive Oxidation Subsurface but a species habitats is Using Sodium conditions. widespread minimal. Injection Permanganate distribution. products are commercially - Hot Spots available from multiple only vendors. • Contaminant mass, as represented by PCE and TCE, is spread throughout the 35 acre SWMU 69 plume. COC Concentrations in groundwater may be migrating to surface water (unnamed tributaries to Young's Lake). COC concentrations have not been detected above surface water criteria at or downgradient from SWMU 69. The contaminant concentrations in groundwater at most monitoring well locations decrease over time, indicating that natural attenuation is occurring. • The subsurface groundwater conditions at SWMU 69 are moderately aerobic, as indicated by high DO concentrations measured during groundwater sampling. Approximately 35 percent of the defined plume foot print is occupied by an electrical sub -station and associated high voltage electrical lines and a marsh area located at the confluence of the two unnamed Young's Lake tributaries. A further 5 percent of the plume area is occupied by steep slopes located on the east and northeast sides of the electrical substation. Thus, approximately 40 percent of the plume area is inaccessible. 10.1.1 Protection of Human Health and the Environment All five alternatives are effective at protecting human health and the environment through a combination of passive or active measures: Because all of the alternatives are effective at protecting human health, an evaluation of the time to reach remedial levels that are protective of human health is the driver in the evaluation. The Alternative 1 timeframe for meeting remedial levels in groundwater that are protective of human health is the longest of all the alternatives and is estimated to be approximately 60 years. The relatively long time frame associated with Alternative 1 is likely to be reasonable because there were no destructive natural attenuation mechanisms identified as being active on site. Thus, the only natural attenuation mechanisms that are 10-3 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc likely to be occurring are nondestructive mechanisms such as dilution, dispersion, volatilization, and sorption. The remedial time frame for Alternatives 2 through 5 will be shorter than that associated with Alternative 1 because the active alternatives are designed to destroy contaminant mass in the "hottest" areas of the plume while allowing natural attenuation mechanisms to reduce COC concentrations in the low concentration areas of the plume. It is difficult to predict how much the remedial time frame will be shortened by applying the active remedial approaches in Alternatives 2 through 5. However, it is likely that the remedial time frame will be shortened to some extent. Thus, while all five alternatives are protective of human health and the environment, Alternatives 2 through 5 are more attractive than Alternative 1 because of the decreased remedial time frames. 10.1.2 Attainment of Media Cleanup Standards All of the alternatives will attain the media cleanup standards for groundwater and eventually. All five alternatives rely in whole or in part on natural attenuation processes to meet groundwater cleanup standards. As discussed in Section 10.1.1, it is likely that the groundwater remedial standards will be met more quickly by applying alternatives 2, 3,4,or5. 10.1.3 Control of Source of Releases The source area associated with SWMU 69 has not been defined. However, five hot spots or areas of elevated COC concentrations have been identified during historic investigations. Alternative 1 contains no provision for source area or hot spot control other than non-destructive natural attenuation mechanisms. Alternatives 2 through 5 contain active treatment mechanisms to destroy contaminant mass present in the five "hot spots," with the goal of reducing the remedial time frame associated with the SWMU 69 plume. Secondary sources of contamination may exist on the site where contaminants have diffused and sorbed into clay layers. Once contaminants in more permeable zones are cleaned up, contaminants diffuse and desorb out of these clay layers into advective groundwater, a. phenomenon know as "rebound" or "back diffusion." Alternatives 2 and 3 (enhanced bioremediation) have a potential advantage over Alternatives 4 and 5 (ISCO). Enhanced bioremediation generally provides longer lasting treatment (years), whereas ISCO tends to be fast acting but reactants are rapidly depleted (days or weeks). Thus, Alternatives 2 and 3 are ranked higher than Alternatives 4 and 5 relative to control of secondary sources. 10.1.4 Comply with Applicable Standards for Management of Waste All of the alternatives will be in compliance with applicable standards of management of waste during their implementation and performance. None of the alternatives, including the treatment portions of the alternatives, generate waste other than IDW soil and groundwater. During the RFI activities, no soil or groundwater IDW was identified as hazardous; therefore, no hazardous waste is anticipated during the implementation of any of the site -wide alternatives. An underground injection control (UIC) Program Permit will be required for Alternatives 2 through 5 prior to the injection of any substance into the subsurface. 10-4 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc f, 10.1.5 Other Factors 10.1.5.1 Long-term reliability and effectiveness The long-term reliability and effectiveness of all five alternatives is dependent upon maintaining institutional controls and maintaining the O&M (primarily monitoring) at the site over the relatively long periods required for MNA associated with these alternatives. Because the site is a government installation with no change in ownership expected over the period of the implementation of the alternatives, the five alternatives have high long- term reliability and effectiveness. 10.1.5.2 Reduction in the toxicity, mobility, or volume of wastes Alternatives 2 through 5 use active remediation to reduce contaminant mass and plume toxicity in groundwater located in the highest concentration areas of the SWMU 69 plume. Alternative 1 uses passive technology to reduce the toxicity in groundwater. Alternatives 2 and 3 use in -situ enhanced bioremediation to reduce the toxicity in the hot spots. Alternatives 4 and 5-use chemical oxidation to reduce the toxicity in the hot spots. Alternative 1 has the least reduction in toxicity because it uses passive treatment (i.e., natural attenuation) to reduce the toxicity in the groundwater. Site conditions at SWMU 69 are not conducive to natural biodegradation, therefore MNA will rely primarily on abiotic and non-destructive processes. Alternatives 2 and 4 are the most effective at reducing the :plume toxicity over the widest area because both of the alternatives apply reactants designed to destroy contaminant mass over a large percentage of the plume footprint. Alternatives 3 and 5 are equally effective at reducing plume toxicity, are less effective than Alternatives 2 and 4 and more effective than Alternative 1. 10.1.5.3 Short-term effectiveness The short-term effectiveness is high for all of the alternatives but varies with the level of implementation required for the individual alternative. Alternative 1 is the most effective in the short-term because it doesn't involve any installation activities other than one monitoring well north of Butner Road and the installation of signage associated with the ICs. There is essentially no environmental or community impact from Alternative 1. Alternatives 4 and 5 are the least effective in the short-term because of the construction associated with the injection of reactants and the potential hazards dealing with a reactive substance (sodium permanganate). Alternative 4 is the less effective in the short-term than Alternative 5 because of the greater volume of reactant and the large area of the SWMU 69 plume footprint (Figure 4.3) including some areas that may be considered wetlands or sensitive species habitat and some areas that are currently occupied by the electrical substation and associated high voltage electrical lines. Careful planning, logistics, and coordination with the entities operating the electrical substation will be required to minimize the potential for community and environmental impact. In addition, careful planning and coordination with the substation operators, including the potential requirement to temporarily shut down the substation, will be required to minimize the potential for severe health and safety hazards associated with working in the vicinity of the substation. Finally, new access routes would have to be cleared in order to apply Alternatives 4. Clearing would include the cutting and removal of numerous trees in Area number l (Figure 9.1) and some grading and backfill operations in Area 2 (Figure 9.1). Clearing and backfilling operations will represent threats to 10-5 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc wetlands and potential sensitive species habitats in both areas, necessitating close coordination with the appropriate regulatory agencies. Alternative 5 would involve the hazards of dealing with a reactive substance, but reactants will be -injected in six small previously defined hot spots only. All six hot spots are located outside of the electrical substation fence and are located in areas that are not considered.to be wetlands or potential wetlands. All 6 hot spot areas can accessed using pre-existing routes, eliminating the potential for impacts to sensitive species habitat associated with clearing and backfill operations. Alternatives 2 and 3 have greater short-term effectiveness than Alternatives 4 and 5 in that injected chemicals are non -hazardous and non -toxic. However, Alternative 2 would involve the access issues described for Alternative 4 (access around the electrical substation, high voltage electrical lines and wetland areas). Alternative 3 therefore has the greatest short-term effectiveness of any of the active alternatives. Carbon substrate would only be injected in six small previously defined hot spots, avoiding the access issues associated with the electrical substation and wetlands. 10.1.5.4 Implementability All five alternatives are technically implementable; however, there is a significant difference in the degree of implementability. For Alternative 1, MNA and ICs, a monitoring well network already exists and will only need to be supplemented with one additional groundwater monitoring well. Monitoring of site media (i.e., surface water, and groundwater) was performed during the RFI for SWMU 69 without any implementation issues arising. Overall, Alternative 1 has a high degree of implementability. From an implementation standpoint, Alternative 1 will be the easiest alternative to implement and will cause the least disruption to the site and surrounding _ areas. ` The large reactant injections associated with Alternatives 2 and 4 are implementable. Enhanced bioremediation using carbon substrate and chemical oxidation using sodium permanganate have been implemented successfully at contaminated sites across the nation. However, Alternatives 2 and 4 will be difficult to implement in the large areas required because of the site specific implementation issues associated with the electrical substation and the wetland/sensitive habitats located in Areas 1, 2, and 4 (Figure 9.1). Thus, from an implementation standpoint, alternatives 2 and 4 would be difficult to implement and would cause the most disturbance to surrounding areas and activities. The hot spot injections associated with Alternatives 3 and 5 are would be moderately implementable because all of the five hot spot areas are accessible using existing access routes. In addition, the five hot spot areas are located outside of the electrical substation and any potential wetland/sensitive species habitat areas. Therefore, from an implementation standpoint, Alternatives 3 and 5 would be moderately implementable and would cause far less disturbance to surrounding areas than Alternatives 2 and 4, but more disturbance than Alternative 1. 10.1.5.5 Costs The approximate total nondiscounted costs for the alternatives are summarized in Table 10.1. Alternative 1, MNA and ICs, is the least expensive alternative. The capital and O&M costs for Alternative 1 are $ 0.11 M and $0.74 M, respectively, for a total cost of $0.85 M. 10-6 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\final\Final SWMU69 CMS.doc Alternative 3, hot spot treatment with organic substrate addition, MNA, and ICS, is the second least expensive alternative (least expensive of the active alternatives). The capital and O&M costs for Alternative 3 are $0.49 M and $0.41 M, respectively, for a total cost of $0.90 M. Alternative 4, large area treatment using chemical oxidation, MNA, and ICs, is the most costly alternative. The capital and O&M costs for Alternative 4 are $2.85 M and $0.41 M, respectively, for a total cost of $3.'.26 M. 10.2 SUMMARY OF ANALYSIS OF CORRECTIVE ACTION ALTERNATIVES The five alternatives are compared to each other for each of the evaluation criteria. By making comparisons between the various alternatives, advantages and disadvantages can be determined between the alternatives. This comparative process aids in the decision - making process since it highlights obvious problems and/or advantages with respect to the criteria. Estimated costs for each alternative are presented in Table 9.1. Table 10.1 provides a summary of results from the comparative analysis. Based on the comparative analysis presented .in Section 10.1, all 5 alternatives are equivalent with respect to protectiveness of human health and the environment. However, the active remedial approaches (alternatives 2 through 5) will reduce COC concentrations in site groundwater to below NC 2L standards more rapidly than alternative one and are therefore superior to monitored natural attenuation and ICs alone. In addition, alternatives 2 through 5 are superior to Alternative 1 in that they provide enhanced control of the source of releases, a greater reduction in toxicity, mobility and volume of waste, and satisfy a statutory preference for active treatment. The active remedial alternatives (alternatives 2 through 5) are. considered to be ....: roughly equivalent in remedial time frame reduction and plumeSay'toxicity reduction (alternatives 2 and 4 may be slightly more effective than alternatives 3 and 5). Alternatives 3 and 5 are superior to alternatives 2 and 4 because alternatives 3 and 5 involve reactant injection in 5 previously defined hot spots that are accessible by existing routes and can be accessed without any impacts to the electrical substation and only very limited potential impacts to wetland/sensitive species habitat areas. Whereas the application of alternatives 2 and 4 will require the removal of numerous trees, the construction of access routes in through wetland areas, and the temporary shutdown of the electrical substation. Alternative 3 is superior to alternative 5 in terms of the control of hot spot mass. Organic substrate addition provides a long term source of reactant mass that will remain in the subsurface to treat contaminant mass that diffuses out of the soil matrix. Whereas ISCO provides reactant mass to the subsurface that lasts only a short period of time, resulting in the potential for COC concentration rebound. In addition, alternative 3 is superior to alternative 5 in terms of cost. Alternative 3 is approximately $160,000 cheaper than alternative 5. Thus, alternative 3 is the preferred alternative for groundwater remediation at SWMU 69. 10.3 CONCEPTUAL DESIGN OF SELECTED ALTERNATIVE This section discusses the proposed corrective measures for the groundwater at SWMU 69. Alternative 3 has been selected for the proposed corrective action at this site. ,- Alternative -3 will include the implementation of LUCs to minimize the potential for 10-7 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc exposure to contaminated groundwater, organic substrate injection in 5 previously J� identified. hot spots, and monitored natural attenuation for the remainder of the groundwater plume. 10.3.1 Establishment of Institutional Controls Administrative controls and groundwater -use restrictions for the SWMU 69 groundwater plume footprint will be incorporated into the BMP. Currently, SWMU 69 is part of a federal installation and is expected to be retained by the federal government for the indefinite future. Groundwater -use restrictions would be implemented to prevent the use of the groundwater for potable water and irrigation. References to relevant corrective action documents for this SWMU will also be included in the BMP. A survey plat for the SWMU will be prepared for inclusion in the BMP. The survey plat will indicate the location and dimensions of the SWMU 69 groundwater plume with respect to permanently surveyed benchmarks. The plat will contain a permanently displayed directive that states Fort Bragg's obligation to prohibit use of the groundwater at SWMU 69 in accordance with this CMS. The previously surveyed groundwater monitoring wells that establish the present extent of groundwater contamination originating from SWMU 69 will be used to establish the perimeter of the SWMU 69 groundwater plume. Institutional controls will include the restriction of groundwater use at SWMU 69. Restrictions on groundwater use for consumption and irrigation would be implemented for the life of this :remedial alternative, estimated to be 20 to 60 years. The groundwater - use restrictions will be implemented during the period of ownership by DoD through the BMP. The BMP will be an effective tool for prohibiting installation of drinking water or irrigation wells at the site while property is under DoD ownership. Groundwater is not currently used as a source of drinking water or irrigation at the site. Institutional controls prohibiting the use of groundwater in the future would be effective at protecting human health from the elevated levels of COCs in the groundwater. The SWMU 69 LUCs will also prohibit intrusive activities within this boundary (e.g., excavation, digging, drilling) without an approved health and safety plan, use of proper personal protective equipment, and other necessary precautions. If soil is excavated from within the SWMU 69 plume area. it must be properly characterized, classified, and disposed of in accordance with Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), Offsite Disposal Rule (40 Code of Federal Regulations [CFR] 300.400). A LUC Boundary for Indoor Air Concerns surrounds the SWMU 69 groundwater contaminant plume. LUCs for this area place limitations on construction of buildings within this boundary due to vapor intrusion concerns. If structures must be sited within this LUC boundary, building design must incorporate appropriate features to mitigate potential for human exposure to chlorinated volatile organic compounds from groundwater. Use of groundwater extracted from within the LUC boundary for potable or agricultural use is prohibited. Specific examples of prohibited uses include drinking, irrigation, fire control, and dust control. Dewatering of excavations or trenches will not be allowed within the SWMU 69 LUC boundary unless contaminated water is properly managed in accordance with applicable state and federal regulations. 10-8 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMSTna1\Fina1 SWMU69 CMS.doc `,, 10.3.2 Complete Groundwater Network One new monitoring well (69MW-22) will be installed to complete the groundwater monitoring network to evaluate the performance of natural attenuation. The location of the new monitoring well will be north of the intersection of Butner and Varsity Roads, as presented on Figure 9.2. The initial groundwater monitoring network will consist of approximately 14 wells. The monitoring well network will be evaluated annually for optimization opportunities. 10.3.3 Enhanced Bioremediation in Hot Spot Areas The purpose of applying enhanced anaerobic bioremediation technology to the SWMU 69 hot spot areas is to reduce contaminant mass present in the subsurface and thereby reduce the time required to reach NC 2L standards in groundwater within the SWMU 69 plume extent. The mixed substrate for this application will consist of a soluble substrate such as high fructose corn syrup to provide an immediate mass Wf io�ble organic carbon to drive geochemistry into anaerobic conditions. and food - grade vegetable oil to provide a slow release source of organic carbon to drive reductive dechlorination over the long term. This mixture typically supports anaerobic io egradation for 3 to 5 years. A pH amendment product such as sodium bicarbonate should also be added to main am neutra PH conditions within each reaction area. Microbial populations capable of dechlorinating chlorinated solvents have been shown to re i ions greater than .2 to live, making pH buffering an The injection well network in each hot spot will consist of approximately 10 to 20 direct push injection points installed in two overlapping arcs. The spacing between the �} injection points will be approximately 10 feet to ensure adequate substrate. distribution. Half of the injection points will be completed as temporary small diametet.wells to allow for future injections of amendments and additional organic substrate if necessary. During the initial injection it is expected that approximately 1,000 to 1,500 gallons of organic substrate mixture and pH amendment will be injected at each point, flooding the area with organic carbon. After the first six months of performance monitoring, the geochemical data and progress of COC degradation in- the hot spots will be reviewed. If degradation is lagging and conditions are sufficiently anaerobic, a supplemental volume of approximately 300 to 500 gallons of dilute bioaugmentation culture and a pH amendment may be injected into each of the small diameter wells. The bioaugmentation culture will consist of a non- pathogenic, naturally occurring population of microbial strains known to be capable of complete dechlorination of PCE, TCE, and 1,1,2,2-tetrachloroethane and its degradation products (cis-1,2-DCE and vinyl chloride). The bioaugmentation culture will be provided by SIREM Laboratories, which has developed a bioaugmentation product called KB-1 that was specifically developed for the degradation of PCE and TCE. A second injection of organic substrate may be applied to the SMWU 69 hot spot areas in the event that the initial injection does not provide adequate organic carbon to the subsurface. 10.3.4 Monitored Natural Attenuation MNA will be an integral part of the selected alternative in that the majority of the SWMU 69 plume area will dissipate through natural attenuation mechanisms while contaminant mass in the hot spots is destroyed through organic substrate addition. The r 10-9 S:\ES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\final\Final SWMU69 CMS.doe successful application of alternative three will require the monitoring of contaminant. levels within the SWW 69 plume to ensure that contaminant concentrations in the groundwater decline over time. Institutional controls, groundwater monitoring, and surface water monitoring will be used to ensure the protection of human health and the environment over the implementation time required to meet remedial goals. Periodic groundwater sampling will be performed to track the progress of natural attenuation and the active remedial activities. Performance groundwater sampling will be performed on a semi-annual basis at 14 wells and two surface water sampling points (coincident with current surface water location 69SW02-06 and a new location at the confluence of the unnamed tributaries south of Butner Road). If groundwater monitoring indicates that contaminant concentrations are declining over time, then the groundwater sampling program may be optimized, including potential reductions in sampling frequency, monitoring well network reductions, and/or analyte reductions. Confirmatory sampling will be performed two years after the last MNA performance sampling. 10.3.5 Monitoring 10.3.5.1 Groundwater Performance Groundwater Sampling. Groundwater will be sampled semi-annually during the first year following carbon substrate injection to evaluate performance of anaerobic reductive dechlorination. Thereafter, performance monitoring will be conducted annually. Groundwater from wells in the vicinity of the carbon substrate injection will be sampled and analyzed for VOCs, TOC, geochemical parameters and pH. Results of the groundwater sampling will be used to evaluate the effectiveness of anaerobic reductive dechlorination and develop plans for subsequent bioaugmentation and carbon substrate injection as necessary. A preliminary monitoring program is summarized in Table 10.2. Performance groundwater monitoring for MNA will be performed on an annual basis to evaluate the progress of the natural attenuation. The location and sampling frequency of wells for performance sampling will be selected based on evaluation of the results of the previous year's performance sampling. Over the first 10 years, it is anticipated that some of the interior wells may be moved to a biennial sampling frequency. However, wells near residential areas (e.g., 69MW-12, 69MW-18D, 69MW-21D, and 69MW-23 [new well]) may remain on an annual sampling frequency. Groundwater will be analyzed for VOCs and natural attenuation parameters. Confirmatory Sampling. Confirmatory groundwater sampling will be conducted for two years after the completion. of the natural attenuation period to ensure that the groundwater contamination concentrations do not rebound. 10.3.6 Investigation -Derived Waste IDW will be generated from the installation of the new monitoring well. The IDW will consist of soil cuttings and wastewater (i.e., development water and decontamination water), and will be characterized for VOCs for determining disposal requirements. Historical knowledge of the waste characteristics of SWMU 69 indicates that other contaminants (e.g., metals, pesticides, etc.) are not a concern. It was assumed that the soil and groundwater IDW will be characterized as non -hazardous based on similar historical waste determinations. Wastewater will also be generated during groundwater sampling events, and will be characterized and disposed of as appropriate. 10-10 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc TABLE 104 PRELIMINARY MONITORING PROGRAM SWMU69: FORT BRAGG, NORTH CAROLINA . Location Identifier... Monitoring Well Installation Water Level Measurement Groundwater Analyses VOCs' (SW8260B) :'Methane, Ethane; .. Ethene.. Nitrate+ : Nitrite. (E300.1). Sulfate (E300.1) : Total Organic Carbon SW9060M) .. 'Well Head . "Analysesb/ Mobile Lab - Analyses` Groundwater. Mbriitori ng Wells . . 69MW 1 t 1 t 69MW6- 69MW9 69MW 10 69MW 12 69MW 14S.... 69MW165 69MW 17S 69MW18D 69MW 19D 69MW21D 69MW22C 1 t 69MW23 x Surface .Water M onitoring Locations New Location .... 1 69SW8 .. .: 1. - . -7. SUBTOTALS : .. 13. 15. .. 5 ..... 4.'. ". 5 7 I3. .. .7 QA/QC ... . Du lcates MS MSD t Trip Blanks 1 -TASK TOTAL 19... - 6 . .: 5-6. 8 14 _ .. 8 . . Volatile organic compounds (VOCs) to include aromatic and chlorinated aliphatic hydrocarbons. Well head analyses include dissolved oxygen, oxidation-reduction potential, pH; temperature, and conductivity. Mobile lab analyses include carbon dioxide, alkalinity, ferrous iron; hydrogen sulfide, and manganese. . CAL Parsons\I. May 2007\I6May07\Ft Bragg\Table 10.2.xls 1041.' 10.3.7 Operation and Maintenance The O&M requirements will be outlined in a corrective measures implementation plan that will be prepared after this CMS document has been finalized. O&M activities associated with alternative three will likely be limited to monitoring well maintenance and site inspections. 10.3.8 Reporting 10.3.8.1 Corrective Action Completion Report A Corrective Action Completion Report will be issued at the completion of the substrate injection activities associated with alternative three. 10.3.8.2 Periodic Progress Reports An annual report will be issued to present the results of the annual sampling events. If the monitoring frequency is reduced, the frequency of progress reporting will be reduced as well to coincide with monitoring events. 10.3.8.3 Periodic Remedy Reviews This site is managed by the Army under the Department of Defense (DoD) Defense Environmental Restoration program (DERP). Paragraph 23.2 of the DoD DERP guidance (DoD, 2001) specifies that periodic remedy reviews be conducted at least every 5 years to ensure that the selected remedy continues to protect human health and the environment. Thus, the remedial action at SWMU69 will be reviewed every five years. The first review will be conducted within 5 years of the selected remedy installation. 10.3.9 Monitoring Well Abandonment Upon concurrence from NCDENR that the corrective action is complete, the monitoring wells will be abandoned in accordance with NC state well abandonment requirements, base well abandonment requirements, or industry best practices, as appropriate. Abandonment will consist of removing the surface completions and grouting the monitoring well/point to ground surface. 10.4 COST ESTIMATE The cost estimate for implementation of Alternative 3 at SWMU 69 is provided in Table 10.1. The estimated 20-year cost is $906,860. This consists of capital costs of $493,860 and O&M costs of $413,000. 10.5 IMPLEMENTATION SCHEDULE Implementation of the corrective actions will begin once approval of this CMS has been received from NCDENR and USAEC. The organic substrate injections will be conducted as soon as all appropriate plans are developed. A detailed schedule will be developed as part of the corrective measures implementation plan. 10-12 SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc SECTION 11 REFERENCES Air Force Center For Environmental Excellence [AFCEE] 2004. Principles and Practices of Enhanced Anaerobic Bioremediation of Chlorinated Solvents, August. Cohen, R.M., and J.W. Mercier. 1993. Dense Non Aqueous Phase Liquid Site Evaluation. CRC Press, Inc. Boca Raton, Florida. Kearney, A. T., Inc., and DPRA Inc., 1988, Interim Facility Assessment Report, Fort Bragg Military Reservation: United States Environmental Protection Agency Region 4, Contract No. 68-04-7038. North Carolina Department of Environment and Natural Resources [NCDENR].1998. Classifications and Water Quality Standards applicable to the Groundwaters of North Carolina: Raleigh, Division of Water Quality, Administrative Code, Title 15A, NCAC 2L, November 20. Office of Waste Programs Enforcement, Office of Solid Waste. RCW Corrective Action Plan, OSWER Directive 9402.3-2A. US Army Corps of Engineers [USACE]. 2003. Savannah District, Site Conceptual Model Report for the Supplemental RFI Investigations of SWMU 69, _ Fort Bragg, NC, August , USACE. 2006. Savannah District, Draft Site Conceptual Model Report for the Supplemental RFI Investigations of SWMU 69, Fort Bragg, NC, May U. S. Census Bureau. 2000. U.S. Census Bureau State and County Quick Facts, available at <http://quickfact.census.gov/gfd/states/37000.html>. U.S. Environmental Protection Agency [EPA] 1994. Final RCRA Corrective Action Plan, Office of Waste Programs Enforcement, Office of Solid Waste, May. EPA. 1995a. Risk Assessment Guidance for SuperFund (RAGS): Vols. 1 and 2, EPA540R-971033, Publication 928.7-01D. U.S. EPA. 1995b. Soil Screening Guidance: User's Guide, 2 Edition, Appendix A, EPN540R-96/018, July. U.S. EPA. 1998. Technical Protocol for Evaluating Natural Attenuation of Chlorinated Solvents in Groundwater, EPN600R-98! 128, September. U.S. EPA Region 4. 1996a. Standard Aerating Procedures and Quality Assurance Manual, May. U.S. EPA Region 4. 1996b. Supplemental Guidance to RAGS: Region 4. Bulletins, Human Health Risk Assessment, November. U.S. EPA, Region 9. 1999. Preliminary Remediation Goals (PRG) Table, October. SAES\Remed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc U.S. Geological Survey, RCRA Facility Investigation at Operable Unit 4, Fort Bragg Installation Restoration Program, Fort Bragg, North Carolina, Volume I, dated April 1999. Volkering, F. and Pijls, C. 2004. Factors Determining Reductive Dechlorination of cis- 1,2-DCE at PCE Contaminated Sites. Proceedings of the Fourth International Conference on Remediation of Chlorinated and Recalcitrant Compounds (Monterey, CA; May 2004). Paper 3D-10. Columbus, OH: Battelle Press. Wiedemeier, Todd H., Rifai, Hanadi S., Newell, Charles J.- Wilson, John T.: Natural Attenuation of Fuels and Chlorinated Solvents in the Subsurface, John Wiley & Sons, INC. New York, New York, dated 1999. 11-2 SAESaemed\745446 Fort Bragg PBC\20010 SWMU-69\CMS\fina1\Fina1 SWMU69 CMS.doc APPENDIX A SELECTED HISTORIC DATA i. Table 4.1 Summary of Lab Results for SWMU 69 Soils - Organics Sample ID Sample Depth Sample Date Concentration SOIL SCREENING LEVELS SB31-35 36 35 36 31 JUL 01 (ug/kg) SB32-35 36 35-36 01 AUG 01 (ug/kg) SB33-10-11 10-11 03 AUG 01 (ug/kg) SE33-32-33 32 33 01 AUG 01 (ug/kg) S1133 35-36 35-36 01 AUG 01 (ug/kg) SB34-0-1 0-1 01 AUG 01 (ug/kg) Reg. 9 I'RG'S Residential (ug/kg) NC Soil to Groundwater (ug/kg) PESTICIDES 8081A 44-DDE 1,700 CA NL BRL BRL BRL BRLEBRL ,•€: (j€ € 4,4'-DDT 1,700 CA 1360 BRL BRL BRL BRLAldrin 29 CA NL BRL BRL ;€1 1Il};{E1€1;1'si BRL BRL Dieldrin 30 CA 1.13 BRL BRL 2 BRL 2.5 Meth ox chlor 31,000 NC 56,000 BRL BRL BRL BRL € BRL - VOC'S (8260B) 1,2 4 Trimeth !benzene 570 NC NL BRL BRL BRL BRL 1A Dichlorobenzene 3,400 CA 1,240 BRL BRL BRL 2-butanone 730,000 NC 692 ;€+k'sg€€ €1,#1$g€':=;€1t €€:: BRL 11's!~2 €€ s': BRL Naphthalene 5,600 NC 585 €€ti1€€s€ BRL '1$sl BRL BRL BRL Sritene, 170,000 NC 2240 's46,21€31€€l BRL M i i 1..110:€ i":€1's € €l;<; .6s €€ € BRL Tehachloroethene 5,700 CA 7.42 BRL ° BRL BRL BRL BRL Toluene 52 0 NC ,00€€U41'•1€€€€1 7,270 1=1 11is ?€i] ' :€€€€':€ :: i:;::s:> l.•::•:.:•:.:: €11.... •: €(]'sli€ BRL Trichloreethene 2,800 CA 18.3 BRL 25 19 110 4 '€ ' 1 :s 1~?1'€€': € BRL X lens 21,000 NC 4,960 €':€0 €s1 €': ''i} 57€ '.€' BRL BRL BRL BRL PCB's 8082 Araclor-1260 220 CA NL BRL BRL BRL BRL BRL CA = Cancerous. NC = Non -cancerous NL - Not listed NS = Not Sampled t` Bold values indicate concentrations detected above SOIL SCREENING LEVELS Shaded areas indicate concentration is above method detection limits but below reporting limits; concentrations are estimated values. Table 4.1 Summary of Lab Results for SWMU 69 Soils - Organics Sample ID SOIL SCREENING LEVELS SB36-35-36 SB39-0-1 SB40-0-1 SB40-6-7 S540-35-36 SB40-18-19 Reg. 9 PRG's NC Soil to Sample Depth 35-36 0-1 0-1 6-7 35-36 18-19 Sample Date Residential Groundwater 31 JUL 01 31 JUL 01 01 AUG 01 01 AUG 01 01 AUG 01 01 AUG 01 Concentration (ug/kg) NNW (ug/kg) (ug/kg) (ug/kg) .(ug/kg) (ug/kg) (u�g) SVOC'S 8270C Benzo a anduucene 620 CA 359 BRL 11€1 1E1 BRL BRL BRL _ _ BRL BRL BRL BRL Chrysene 62,000 CA 39,800 BRL €7'4f€1s@s':.: BRL Fluoranthcne 230,000 NC 276,000 BRL €€ECO[I ? E €sElE1''s`'' BRL BRL BRL Phenanthrene NL 59,600 BRL€1€49 6111's's€ € BRL BRL BRL P e 230,000 NC 286,000 BRL 1€11?#111s'€?'€1'11 BRL BRL BRL VOCis (8260B) �l••=€1i:1:1 11€ik€@€11€€: €': 1101€':€1€ ' 1,2,4 Ttimethylbenzene 570 NC BRL .•. - ..• - '• 1,3,5 trimethylbenzene 2,100 NC NL BRL BRL BRL BRL s1::::a; $ :111 BRL 1,4 Dichlorobenzene 3,400 CA NL €141'i€ €€ BRL BRL BRL BRL BRL _ 2-butanone 730,000 NC 1,2401':.1E¢Es BRL Acetone 160,000 NC 692 BRL BRL I i I ii 1 ip iC9 `; ' _ BRL BR- BRL Chloroform 240 CA 2,810 BRL BRL BRL BRL 1' 1 601€€ BRL Naphthalene 5,600 NC l585 I EY1;E::1:; BRL BRL BRL EiiQc€i E1 BRL S e 170,000 NC 2,240 BRL BRL BRL ` 1 %a s;... BRL BRL TetrachUoroethene 5,700 CA 7.42 -BRL ..��?'•11 `•1 .:��€`�€1'�' `� Toluene 52,000 NC 7,270 BRL :`.€�8'� �?€; 1�'Q$.�€€1: + � . �..• Trh hloroethene 2,800 CA 18.3 BRL BRL 4J € € '€ € 6.0 BRL 26 X lenes 21,000 NC 4,960 '€'::i€ €=;=.°s€ BRL. 1at�G>€€'•€€€1R'si$111s1@'ss 0.72 PCB's (8082) Aroclor-1260 220 CA NL BRL 49 120 BRL BRL_ BRL CB = Cancerous NC = Non -cancerous NL = Not listed NS = Not Sampled Bold values indicate concentrations detected above S07L SCREENING LEVELS Shaded areas indicate concentration is above method detection limits but below reporting limits; concentrations are estimated values. Table 4.1 Summary of Lab Results for SWMU 69 Soils - Organics Sample ID Sample Depth Sample Date Concentration SOIL SCREENING LEVELS SB41-23-24 23-24 02 AUG 01 (ug/kg) SB41-35-36 35-36 02 AUG 01 (ugtkg). SB42-0-1 . 0-1 02 AUG 01 (ug/kg) SB42-35-36 35-36 02 AUG 01 (u94k8) SB43-0-1 0-1 02 AUG 01 (ug/kg) SB434-5 4-5 01 AUG 01 (uglkg) Reg. 9 PRG's Residential (ug/kg) NC Soil to Groundwater (ug/kg) PESTICIDES 8081A) 4,4'-DDE 4N-DDT 1,700 CA 1,700 CA NL 1,360 BRL BRL BRL BRL ?€€R's5'.'':'• i B s€ 13 € € € BRL BRL BRL BRL BRL BRL Aldrin 29 CA NL BRL BRL BRL €:_Ir,SA€ BRL BRL Dleldrin 30 CA 1.13 5.3 €,$"s;i': 4.5 20 BRL BRL Endrin 1800 NC 440 ='s• 0 3 € € € € € BRL Bill, BRL BRL BRL VOC's (8260B 1,2,3 Trichlorobenzene 1 4 Trimeth lbenzene NL 570 NC NL NL BRL /� 'eaQi?Ai€€'''ss BRL is€€'•€ BRL BRL BRLB. ERR €€€€ € 1,4 Dichlombenzene 3,400 CA 1240 BRL BRL BRL BRL BRL': 2-butanone (MEK) 730,000 NC 692 BRL BRL BRL € € € > Acetone Naphthalene 160,000 NC 5,600 NC 4810 585 BRL BRL BRL BRL BRL BRL BRL BRL `. 1 C. '• € � :`. `:€ iEl� l €€ Styrene 170,000 NC 2,240 BRL €OT.''' BRL •l,n Tetrachloroethenc 5 700 CA 7.42 E€ @`•a€€€ BRL €€2_€s; ;s BRL BRL Toluene 52,000 NC 7,270 l ..... 's 11 i2 ? a). . Trichloroeth'ene 2,800 CA 18.3 45. 8.2 BRL 49 BRL BRL Xylenes 21,000 NC 4,960 €'s Q t`: €€; €€I#�4€'•. ``: BRL ss0€ BRL BRL PCB'. 8082) Aroclor--1260 220 CA NL BRL BRL 24 BRL BRL BRL CA = Cancerous NC = Non -cancerous NL = Not listed NS = Not Sampled Bold values indicate concentrations detected above SOIL SCREENING LEYELS Shaded areas indicate concentration is above method detection limits but below reporting limits; concentrations are estimated values. Table 4.1 Summary of Lab Results for SWMU 69 Soils - Organics Sample M SOIL SCREENING LEVELS SR43-7-8 - - - - - . - - I - - . SB45 ' -5-36 Sample Depth 7-8 35-36 35-36 0-1 5-6 35-36 Reg. 9 PRG's NC Soil to Soil Sample Date Residential nu Groundwater 02 AUG 01 02 AUG 01 04 AUG 01 05 AUG 01 05AUG 01 05AUG OI Concentration (ugtkg) RgI g) (uglkg) (Ugtkg) (ugtkg) (ugtkg) (ug/kg) (ug/kg) (uglkg) PESTICIDES (8081A) Aldrin 29 CA NL BRL Rd9. BRL BRL BRLDieldrin 30 CA 1.13 BRL 2.9 3.6 BRL BRL BRL VOC's (8260B) 1,2,3 Trichlorobcuzeno NL NL BRL BRL BRL BRL BRL TrimdhylbTzcnc 570 NC NL BRL BR BRLIA4 01, A:; 1.3,5 bimethylbemene 2,100 NC NL BRL BRL BRL BRL BRL 1,3 Dichloropropane NL NL BRL BRL BRL BRL BRL 1,4 Dicblorobenzene 3,400 CA 1,240 BRL 2-butanone (MEK) 730,000 NC 692 -BRL BRL BRL Acetone 160,000 NC 2,810 BRL BRL 10 BRL Chloromethane 1,200 CA NL BRL BRL BRL BRL BRL Meth yl-tert-butyl ether NL 916 BRL BRL - , , I.. i i I '- BRL BRL BRL Naphthalene 51600 NC 585 *..-*!Iii-ii.::�zigi-.;ii.!iii.'� ....... ....... : : ii1iti.,ii' '! BRL BRL ::.::::t::h:*. 13RL BRL Styrene 170,000 NC 240 BRL !, . . . . . . . . . . . . . . . . . i-i-Ii!R"i NN, Tetz ic -achloro 5,700 CA 7.42 BRL j 1.� 247! i.- Toluene 52;OOO'NC 7,270 11 711 Bil 1-1-5 Trichloroethene 2,800 CA 18.3 BRL 16 BRL BRL —.: BRL BRL Xylenes 21,000 NC 4,960 BRL BRL ..... CA - Cancerous NC = Non -cancerous NL =Not listed NS = Not Sampled Bold values indicate concentrations detected above SOIL SCREENING LEVELS Shaded areas indicate concentration is above method defection limits but below reporting limits. concentrations are estimated values. Table 4.1 Summary of Lab Results for SWMU 69 Soils - Organics Sample ID Sample Depth Sample Date Concentration SOIL SCREENING LEVELS SB46-0-1 0-1 05 AUG Ol (ug/kg) SB46-4-5 4-5 05 AUG Ol (ug/kg) SB46-12-13 12-13 OS.AUG Ol (ug/kg) SB46-31-32 31-32 OS AUG Oi (ug/kg) SB47 3-4 3-4 Ol AUG Ol (ug/kg) SB47-31-32 31-32 Ol AUG Ol (ug/kg) Reg. 9 PRG's Residential (UK/kit), NC Soll to Groundwater (ug/kg) PESTICIDES 8081A Dieldrin 30 CA 1.13 BRL BRL BRL BRL BRL VOC's 8260B) 1,2,4 Trimetb lbea=e 570 NC NL BRL BRL BRL BRL € €€ 9 € €€ @@ @@€€€ €€ f 7 € c € 1,4 Dieblombentene 3,400 CA 1240 iiit4€ €bl's'€6 € s0>i'2€I€= TRW b€F €: BRL BRL 2-butanone 730,000 NC 692 €`1€ ':� •€1!€'s BRL BRL BRL BRL Acetone I60 000 NC 2,810 ;16;';€` : €€€SK7€ I BRL BRL €g;l € €' BRL Nap bthalene 5,600 NC 585 BRL BRL BRL BRL €id?€=i�4€°-€ ' Styrene 170,000 NC 2,240 SRL €'s tk € €s €'•` 's @ b= i t€'• ': ` BRL ? k1<5. . ` ll5i! Tetracblomethenc 5 700 CA 7.42€a��' Toluene 52,000 NC 7,270 :::;E.�i€€€....... ��.'�� ?'.�� `' ::.R .. ........... . ,#'1�€€� � , ........ Trieblomethene 2,800 CA 18.3 BRL BRL BRL BRL 7.2 BRL X lanes 21,000 NC 4,960 CA m Cancerous NC - Non -cancerous NL = Not listed NS - Not Sampled Bold values indicate concentrations detected above SOIL SCREENING LEVELS Shaded areas indicate concentration is above method detection limits but below reporting limits; concentrations are estimated values. I— Table 4.1 Summary of Lab Results for SWMU 69 Solis - Organics Sample ID Sample Depth Sample Date Concentration SOLI SCREENING LEVELS SH47-35-36 35-36 01 AUG 01 (ug/kg) SB48-0-1 0-1 03 AUG 01 (ug/kg) -1 -1 14-15 03 AUG 01 (ug/kg) 24-25 03 AUG 01 (ug/kg) —Reg. —9PRGIS Residential (ug/kg) NC Soil to Groundwater (ug/kg) PESTICIDES(8081A) Dieldrin 30 CA 1.13 BRL L BRL VOC's 260B) 1.2,3 Trichlarobenzene NL NL BRI. - BRI. BRI. BRL 1,2.4 Trimethylbeozene 1,4 Dichlorobenzme 2-butanone 570 NC 3,400 CA NL 1240 : 41 11 i, . -115 1 i I BRL BRL BRL BRL 730,000 NC 692 4-meth 1-2- entanone 79,000 ' NC 2,280 BRL BRL BRL BRL Acetone 160,000 NC 2,810 BRL BRL BRL Dichorodifluoroinedme 9,400 NC 306,000 BRL BRI. BRI. BRL NaphthaIene 5,600 NC 585 BRL BRL BRL Styrene 170,000 NC 2.240 BRI. BRI, iiiiiii! Tetrachloroethene 5,700 CA 7.42 BRL BRI, BRL Toluene 52,000 NC 7270 8 Trichlaroethene 2,800 CA 183 8.6 BRL Xylenes 21,000 NC 4,960 BRL BRL BRL PCB's 0082) Atoclor-1260 220 CA NL BRL BRL CA = Cancerous NC = Mon -cancerous NL =Mot listed NS = Not Sampled Bold values indicate concentrations detected above SOIL SCREENING LEVELS Shaded areas indicate concentration is above method detection limits but below reporting limits,- concentrations are estimated values. Table 4.1 Summary of Lab Results for SWMU 69 Soils - Organics Sample ID Sample Depth Sample Date Concentration SOIL SCREENING LEVELS SB39-35-36 35-36 01 AUG 01 (ug/kg) S84&35 36 35-36 03 AUG 01 (ug/kg) SB49 20-21 •20-21 03 AUG 01 Oig/kg) SB49-34 35 34-35 03 AUG 01 (ug/kg) SH50-3435 34-35 03 AUG 01 (ne/kg) SB51-24-25 24-25 04 AUG 01 (ug/kg) Reg. 9 PRG's Residential (ug/kg) NC Soil to Groundwater (ug/kg) PESTICIDES 8081A Aldiin 29 CA NL NS BRL _ BRL BRL_ EEEEEOE%7SE EE€€':. €E1EE€ BRL Diefdrin 30 CA 1.13 NS BRL ^BRL 5.6 BRL VOC's (8260B 1 4 Trimethylbenzene 1,4 Dichlorobenzene 2-butanone NL 3.400 CA 730,000 NC NL I,240 692 ES(E: ESE SESESE •� BRL EE€E€EOE'3EEEE.EE'.::: BRL Eaf1EEEESEEEs; BRL ESES€ Q:?6rE€ ::=':'ESE ;ESE;€EsEa7�1SE€EEE`EfE BRL SESES€ Ed€ +l'fSEs€ € EEi4 €: ': '<SES .. BRL BRL :SEE E € ":€SEi)....... SESESEI#s5$SEEEEES BRL .€ ES QE80EESEEE€ BRL Chloromedme 1,200 CA NL '> S ES1 E€E E EEESE BRL BRL BRL BRL BRL Na hthalene 5,600 NC 585 :: ::tt !'=€4EE °•' EEE:1EsE€EEs BRL BRL BRL BRL StY1=e TUrachloroethene Toluene Trichloroethene X lens 170,000 NC 5,700 CA 52,000 NC 2,800 CA 21,000 NC 2,240 7.42 7,270 18.3 4,960 EEIi)EEE EE;'4;lESESEEEEESES EE§1�EEESEEE<�€'•• 33 EEEE?6EE':EEE::: EE SEEgE€EEEESEE`. BRL. ES €€4�QEE€EEEE ESE1 IEEE@EESSE€ : BRL BRL S : lE?: € €E :: S� ESEEEIS . E:E2 iESE EEEE` EEEQ?l E€EEEEEE:E ED•,&E;EEE€. SESESE".. . •. > 6.0 EEEO t3lE:EEEEEE: BRL SE.1i ': EEE(#gs ?E€EE BRL iaEE:E= €€s . ... EEEEEE ' : BRL CA = Cancerous NC = Non -cancerous NL = Not listed NS = Not Sampled Bold values indicate concentrations detected above SOIL SCREENING LEVELS Shaded areas indicate concentration is above method detection limits but below reporting limits, concentrations are estimated values. Sample ID Sample Depth Sample Date Concentration SOIL SCREENING LEVELS SB51-35-36 35-36, 04 AUG.01 (nglkg) : SB524-5 4-5 04,AUG 01 (uglkg). S1152-35-36 35-36 04 AUG 01 (ug/kg) SB55-0-1 0-1 01 04. LUG (aWkg) . SB55-10-1 l . 10-11 04 AUG 01. (ugIM SB55-25-26 25-26 0.4 AUG 01 (ugikg)-'. . Reg. 9 PRG's Residential Ng/kg) NC,Soil to . . Groundwater.: (ug/kg) 'PESTICIDES 8081A . 4,4'-DDE 1,700.CA NL .BRL BRL BRL ;;Xali BRL. . 4,4'-DDT 1,700 CA 1,360 BRL. BRL BRL @€ij;i@ BRL Aldrin . 29 CA. NL ::':`::: 6�€a ::::. .Dieldrin BRL BRL BRL jBR BRL - 30 CA 1.13 €<$€ i €€€. BRL 06i'€4€€€ BRL VOC's (8260B) . . 1,2,4 Tritneth l6enzene 1,3 Dichloro ro ane NL NL NL NL BRL BRL BRL . BR . BRL BRL . BRL € €059.. €€€ • BRL "- BRL BRL BRL 1,4 Dichlocvbenzene `3,400.CA 1,240 €€Q€i'SE€E�1 ��'s€ €�R.........�s41.11 s85@'s €� -9€ 2-butanone 730,000 NC 692 -,,BRL, BRL BRL = BRL. Acetone 160,000. NC 2,810.. 'BRL>g ` € BRL ? 8.'%; BRL:: BRL S ZYme Tehachlotaethene Toluene Trichlotoethene 170 000. NC 5 700 CA 52.000 NC 2,800 CA . 2,240 7.42 ' . 7,270 18.3 tl6€':= €€I€�i�'s?€i� €€s(l';k€ii€s€€0'2 €€€€A@;1's@€> ::.. €0=3€ ;.:.,. . :;d:$s€....•.::: `••€€ ` BRL. 0 •:;f:�l€?�€�€ is€1r 's €€�2€€s€€ :BRL € _ _, •'€....X ......... - 5.6 BRL�59 ..... �.1..... BRL s1€ ::::il,i ::.•.- Xylenes -. 21,000'NC 4,960. HRL €I1 BRL.- BRL. € €6E € siF2i1i8E€. Cif = Cancerous NC = Non -cancerous NL=Not listed . NS = Not Sampled Bold values indicate concentrations detected above SOIL SCREENING LEVELS Shaded areasindicate concentration is above method detection. limits but below reporting limns; concentrations are estimated values. Table 4.1 Summary of Lab Results for SWMU 69 Solis - Organics Sample 1D Sample Depth Sample Date Concentration SOIL SCREENING LEVELS SBSS-35 36 35-36 04 AUG Ol (ug/kg) SB56-0-1 0-1 05 AUG Ol (mg/kg) S11564-5 1 4-5 06:AUG Ol (ug/kg) SB5641-9 8-9 06 AUG Ol (ugikg) SB56-3536 35 36 06 AUG Ol (ug/kg) Reg. 9 PRG's Residential (uglkg)" NC Soil to Groundwater (HOW PESTICIDES 8081A Dieldrin 30 CA 1.13 BRL BRL BRL BRL €€1€ €f fec€ VOC's (8260B) 1.2.4 Trimeth ibcnzene NL NI, BRL BRL BRL BRL BRL 1,3,5 trimethylbenzene 2,100 NC NL _ BRL BRL BRL BRL BRL 14 Dichlorobenzene 3,400 CA 1240 €d:�i€€ �€@€s€s'a#1€i€�'s :�€:R 93€s::€€:'• €1#'.$lr:€ € 2-butanone 735,000 NC 692 €€ O;t; € € s 6 €: @ ;l'I 1€1€ €'s€ €: €'€ ?,' € € BRL BRL 4-meth 1-2- entanone .79,000 NC 2,280 BRL l BRL BRL BRL BRL Acetone 160,000 NC 2,810 BRL €'s2s€€'s€ €€ €€ 5 €€ BRL BRL Benzene 670 CA 5.62 BRL BRL BRL BRL BRL Dichorodifluoromethane 9,400 NC 306,000 BRL BRL B Ui = € BRL Styme 170.000 NC 2A40 BRL BRL BRL Tetrachloroethene 5,700 CA 7.42 1Y+.. €€�>�2YaE'•�<€€= � €=�. (:•:• Toluene 52,000 NC 7,270•''€ :::+:::• BRL Trichloroethene 2,800 CA 18:3 120 6.4 >°:k0€':€@€@" BRL Xylenes 21,000 NC 4,960 �8�;�@E1`:s's�`:i € €��9�•�'• �� d06Q€'€:�':��'s€� . : "1�. . CA - Cancerous NC = Non -cancerous NL = Not listed NS = Not Sampled Bold values indicate concentrations detected above SOIL SCREENING LEVELS Shaded areas indicate concentration is above method detection limits but below reporting limits; concentrations are estimated values. Table 4.1- Summary of Lab Results for SWMU 69 Solis - Organics Sample ED Sample Depth Sample Date Concentration SOIL SCREENING LEVELS SB58-4-5 4-5 06 AUG 01 (ug/kg) SB58-21-22 21-22 06 AUG 01 (ug/kg) SB58-25-26 25-26 06 AUG 01 (ug/kg) NB55-3233 32-33 06 AUG 01 (ug/kg) Reg. 9 PRG's Residential NC Soil to Groundwater (ug/kg) VOC's (8260B) 1.2,4 Trimethylbenzene NL NL BRL BRL BRL BRL 1.3,5 trimethylbenzene 2,100 NC NL BRL BRL BRL 1,3 Dichlorapropane 1,4 Dichlorobenzme NL 3,400 CA Nl. F24_0 BRL BRL BRL BRI, 2-butanone 730,000 NC 692 BRL BRL BRL BRL. BRL 4-mathy1-2-pentanone 79,000 NC 2,280 BRL BRL BRL Chloroform 240 CA 1.01 BRL BRL BRL Meth yl-tert-butyl ether NL _916 BRL BRL BRL BRL Dichorodifluoromethane 9,400 NC 306,00 BRL BRL Athylbenzene 23,000 NC 241 BRL BRL BRL BRL Isopropylbenzene 16,000 NC NI, BRL BRL BRL BRL Naphaialene 5j600 NC 585 BRL BRL BRI. BRL stmae Tetrachloroothene 170,000 NC 5,700 CA 2,240- 7.42 BRL fgi BRL Toluene Trichloroethene Xylenes 52,000 NC 2,800 CA 21,000 NC 7 27_0 18.3 4,960 M Mi. N. ! BRL 110 CA =Cancerous NC - Non -cancerous NL = Not listed NS = Not Sampled Bold values indicate concentrations detected above SOIL SCREENING LEVELS Shaded areas indicate concentration is above method detection limits but below reporting limits; concentrations are estimated values. _j Table 4.2 (Oct., 2002) Summary of Laboratory Results for Ground -Water Samples Collected Various Investigations of SWMU 69. Well Results (µg/L) Number Analyte NC 2L Region 9 Ground- Groundwater MCL PRG water Protection Tap Water Elevation STDS (2002) 8/2001 (ug/1) (ug/1) 4/1995 8/1998 10/2000 8/2061 9/2002 (Method 8240, (N2ethad 8260, (Method 8260, Method 8260, Method 8260, Reporting Reporting Reporting Reporting Reporting limits for limits for limits for limits for limits for TCE/PCE was TCE/PCE was TCE/PCE was TCE/PCE was TCE/PCE was 5.0u IL) 1.0u ) 0.5u AL I.0u 1.0u 69MW1 Tetrachloroethene(PCE) 0.7 5 0.66CA 211 3.2 2.6 21 15 13 253.49 Trichloroethene (TCE) 2.8 5 0.028 CA CA 251 5.2 13J 6.8 42 OAM 0.36J UM Chloroform Dieldrin 0.19 0.0022 80 NL 0.53 0.0042 CA 0.12 <O.IOUJ NS NS NS Mblh lone Chloride 5 5 4.3 CA 3.8 69MW2 Tetrachlaroethene(PCE) 0.7 5 0.66CA -UJ 0.14j - 1.8 - 1.4 254.29 Trichlorcethene (TCE) Dieldrin 2.8 0.0022 5 NL 0.028 CA 0.0042 CA -UJ 0.33j <O.IOUJ - NS NS UM Chloromethane 2.6 NL 1.5 CA _UJ 0.56J Acetone 70D NL 61O NC _ 2.2J 69MW3 Tetrachlorcethene (PCE) 0.7 5 0.66 CA - 0.32j 254 254.56 Triebloroethene (TCE) 2.8 5 0.028 CA - 0.22j - - Chloroform 0.19 80 0.53 CA 1911 OA6j 6.2 24 UM l3is(2-ethylhexyl pthatlale 3 6 4.8 CA 1.3.1 _ Dieldrin 0.0022 NL 0.0042 CA <O.IOUJ NS NS NS Bromodichloromethane 0.6 80 OASCA 0.34J 69MW4 All analytes - - - NS NS - 285.15 PEARCHEli UM- Upper Middendorf NC= Non -cancerous J= vame is esnmateu occause-iess tuna reporting canna LM- Lower Middendorf CA= Cancerous J= value is estimated due to problems with quality control in lab Cb=Cape Fear NCB Non -cancerous U= same contaminant detected in trip or lab blanI4 value reported is too high. na- not analyzed. NS- Not Sampled W- analyte Is not detected; however, detection limit may be inaccurate. Bold= exceeded NC 2L standards = Below Method Detection Limit or Not Applicable Table 4.2 (Oct., 2002) Summary of Laboratory Results for Ground -Water Samples Collected During investigation of SWMU 69 (Cout.) 69MWS Tetrachloroetlicnc (PCE) 0.7 5 0.66 CA - 0.98j - - 252.91 Trichloroethenc (TCE) 2.8 5 0.028 CA 6.2 0.25j 2.3 Chloroform 0.19 80 0.53 CA UM Bis(2-ethylliexyl) pthatlate 3 6 4.8 CA I AJ Acenaphthene 80 80 370 NC 2.5j 4-Chloro-3-methylphenol NL NL - 3.4i - 2,4-Dinitrotolucne NL 73 NC - 3.3j N-Nitrosodi-n-propylamine NL 0.0096 CA 2.2j Pryene 210 NL ISONC 4.5j Dieldrin 0.0022 NL 0.0042 CA <0.1 OLIJ NS NS NS 69MW6 Tetrachloroethene (PCE) 0.7 5 0.66 CA 0.12j 0.5 0.591 - 252.12 Trichlorocthene (TCE) 2.8 5 0.028 CA 89 26 51.0 75 91 Chloroform 0.19 80 0.53 CA 0.211 0.74 1.0 UM Dieldrin 0.0022 NL 0.0042 CA <0. I OLIJ NS NS NS Cis-1,2-Dichloroethene 70 70 61 NC - - 2.2 2.1 2.6 69MW7 Carbon Tetrachloride 0.3 5 0.17 CA - 0.43j 0.39J - 253.64 Chloroform 0.19 80 0.53 CA 0.80j 4.0 2.0 Dieldrin 0.0022 NL 0.0042 CA <0.)OUJ NS NS UM 69MWS Acetone 700 NL 61O NC NS 21 U - 145.68 Benzene 1.0 5 0.34CA NS 0.14j - CF 69MW9 Tetrachloroetircnc (PCE) 0.7 5 0.66 CA 2.3 2.3 6.7 13 253.47 Trichloroethcnc (TCE) 2.8 5 0.028 CA 24 0.74j 0.5 0.841 1.2 Chloroform 0.19 80 0.53 CA 7.9 034j - - 033 UM Dieldrin 0.0022 NL 0.0042 CA 0.03ti' NS NS NS UM- Upper Middendorf NC- Non -cancerous j= value is estimated because less than reporting umrt LM- Lower Middendorf CA- Cancerous J= value is estimated due to problems with quality control In lab CF-Cape Fear NC- Non -cancerous U= same contaminant detected in trip or lab blank, value reported is too high. na- not analyzed. NS- Not Sampled UJ= analyte is not detected; however, detection limit may be Inaccurate. Bold- exceeded N C 11, standards -= Below Method Detection Limit or Not Applicable Table 4.2 (Oct., 2002) Summary of Laboratory Results for Ground -Water Samples Collected During Investigation. of SWMU 69 (Cont.) 69MW10 Tetrachloroethene (PCL) 0.7 5 0.66 CA 26 25.8 25 32 252.83 Trichloraethene (TCE) 2.8 5 0.028 CA 19 23 35.5 18 5.9 Chloroform 0.19 80 0.53 CA - 1.2 0.6 053J 0.43J UM Bis(2-ethylhexyl)pthadate 3 6 4.8 CA 1.ej Dieldrin 0.0022 NL 0.0042 CA '<O.IOUJ na 69MW11 Benzene 1.0 5 0.34 CA Not Installed 0.54j 232.56 Chloroform 0.19 80 0.53 CA 0.14j Chlorometbanc 2.6 NL 1.5 CA - OAQ UM Acetone 700 NL 610 NC 2.9J 69MW12 Tetrachloroetheuc (PCE) 0.7 5 0.66 CA _ Not installed 0.34J - 0.32J 0.42J 241.26 Trichloroethene ('ICE) 2.8 5 0.028 CA 42J 28.3 30 28 Chloroform 0.19 80 0.53 CA 0.56] 0.37 0.473 LM Benzene 1.0 5 0.34 CA 0.17J 2-Butanone 170 NL NL 0.84J 1.2-Dichloroethane 700 5 0.12 CA 0.17J 1.2-Dichloroethcne NL NL 1.61 0.95.1 Carbon Tetrachloride 0.3 5 0.17 CA 0.21J - Methylene Chloride 5.0 5 4.3 CA LOU - Chloromethane 2.6 NL 1.5 CA 0.591 Cis-1-Dichloruethene 70 70 61 NC 0.74 69MW13 Tetrachlomethene (PCE) 0.7 -5 0.66 CA Not Installed 0.21.1 - - well broken Trichloroethcne (TCE) 2.8 5 0.028 CA 1.1 - 0.46J Chloroform 0.19 80 0.53 CA 0.223 - LM Benzene 1.0 5 0.34 CA 1.4 Ethylbenzene 29 700 2.9 NC 1.2U - Methylene Chloride 5.0 5 4.3 CA 0.11J - Chloromethanc 2.6 NL 1.5 CA - 0.89J 69MW14S Tetmchloroethcne (1'CE) 0.7 5 0.66 CA Not Installed 0.27j 253.09 Trichloroethene (TCE) 2.8 5 0.028 CA 5.1 3.9 75 Chloroform 0.19 80 0.53 CA 0.16j - UM Methylene Chloride 5.0 5 4.3 CA I.4 - 1,2-Dichloroohnne 700 5 0.12 CA 0.67 1.1 2,2r-Tetrachloroethane 0.17 NL 0.055 CA 0.40 UM- Upper Middendorf NC -Non -cancerous j- value is estimated because less than reporting limit LM- Lower Middendorf CA= Cancerous J= value is estimated due to problems with quality control in lab CF=Cape Fear NC -Non -cancerous U= same contaminant detected in trip or lab blank, value repotted is too high. no- not analyzed. NS- Not Sampled UJ- analyte is not detected; however, detection limit may be inaccurate. Bold- exceeded NC 7L standards Below Method detection Limit or Not Applicable Table 4.2 (Oct., 2002) Summary of Laboratory Results for Ground -Water Samples Collected During Investigation of SWMU 69 (Cont.) 69MW14D elhcne (PCE) 0.7 5 0.66 CA Not Installed 0.3tj 251.16 thene (TCE) 2.8 5 0.028 CA . 5.6 0.19 80 0.53 CA 032j LM hane FChloromethanc 2.6 NL 1.5 CA O.1(j 0.68Jtrachloraethane 0.17 NL 0.055 CA 1.0 0.42Julfide 700 NL IOOONC 0.26j OAIJ cco 700 NL 610 NC 7.01 1,2-Dichloroethane 038 5 1 0.12 CA 1.7 1.4 69MW15S All analyzes - Not Installed - 257.26 UM 69MW15D Tetrachloroetlrcne (PCE) 0.7 5 0.66 CA Not Installed 0.24j 0.37J 250.77 Trichloroethene (TCE) 2.8 5 0.028 CA OAIj 0.48J 0.36J Chloroform 0.19 80 0.53 CA 0.14j 0.38J 0.40J LM Carbon Disulfide 700 NL 1000 NC 17 Acetone 700 NL 610 NC 4.2.1 Toluene 1,000 1,000 720NC O.I9j 4-Meth 1-2- entanone NL NL 13 - - 69MW16S Tetrachloroethene (PCE) 0.7 5 0.66 CA Not Installed OA5j - 0.37.1 - 251.42 Trichloroethene (TCE) 2.8 5 0.028 CA 73 7.8 20 19 Chloroform 0.19 80 0.53 CA 0.30i - 0.67J 0.64.11 UM Chloromethane 2.6 NL 1.5 CA - 0.70.1 - Cis- 1,2-Dichloroethene 70 70 61 NC - - 0.611 0.71J 69MW16D Tetrachloroethcne (PCE) 0.7 5 0.66 CA Not installed - - 250.40 Trichloroethene (TCE) 2.8 S 0.028 CA 0.19j - Chloroform 0.19 80 0.53 CA 0.36j - OAOJ 0391 LM Carbon Tetrachloride 0.3 5 0.17 CA 0.31j OASJ 12-Dichioroethane 0.38 NL 0.12 CA 0.59' 1.0 0.61J UM= Upper Middendorf NC- Non -cancerous j- value is estimated because Tess than reporting rrmrt LM- Lower Middeudarr CA- Cancerous J= value is esfunated due to problems with quality control in lab CF-Cape Fear NC- Non -cancerous U- same contaminant detected in trip or lab blank, value reported is too high. uam not analyzed. NS= Not Sampled UJ- onalyte is not detected; however, detection limit may be inaccurate. Bold- exceeded NC 2L standards - Below Method Detection Limit or Not Applicable Table 4.2 (Oct., 2002) Summary of Laboratory Results for Ground -Water Samples Collected During Investigation of SWMU 69 (Cont.) 69MW17S Tetrachlorcethette (PCE) 0.7 5 0.66 CA Not installed 24 15.5 ' 25 4.8 21 4.4 250.75 250 Trichloroethene TCE) 2.8 5 0.029 CA 9.1.1 3.6J 3.2 5.0 4.5 3.1 Chloroform 0.19 80 0.53 CA UM Carbon Tetrachloride 0.3 5 0.17 CA 0.131 Chloromethane 2.6 NL 1.5 CA 0.69J - 69114W17D Tetrachloroethene PCE) 0.7 5 0.66 CA Not installed' 0.32j - 1.6 2.1 1.2 0.513 250.39 Trichloroethene (TCE) 2.8 0.19 5 80 0.028 CA 0.53 CA 7.8 0.37j 0.66 0.82J LM Chloroform Carbon Disulfide 700 NL 1000 NC 0.1!)j = Acetone 700 NL 610 NC 12) 10 2•Dutanooe 170 NL NL 0 9..5j Methylene Chloride 5.0 5 4.3 CA 0.54J 1,1,2,2-Tetrachloroethane 0.17 NL 0.055 CA 2.2 0.651 69MWISD Tetrachloroethene (PCQ 0.7 5 0.66 CA Not installed 0.30j 0.37J 0.40J 24 0.80 24 Trichloroethene (TCE) 2.8 5 0.028 CA 0.53 CA 49 0.50j 45.7 - 49 0.36.1 38 0.38J Chloroform 0.19 80 LM Carbon Tetrachloride 0.3 5 1000 NC 0.15j 1,2-Diehloroethane 0.38 5 0.12 CA 0.27 - 0.44.1 4-Methyl-2-pentanone NL NL 0.85j - - Chloromethane 2.6 NL 1.5 CA - 0.82.3 - 1,1,2,2,-Tetrachloroethane 0.17 NL 0.055 CA - 038J 0.513 Cis-1,2-Dichloroelhene 70 70 61 NC - - 1.2 1.3 69MW19D Tetrachloroethene (PCE) 0.7 5 0.66 CA Not installed 0.75J 2.5 2.9 4.1 239.17 Trichloroethene (TCE) 2.8 5 0.028 CA CA i8 0.92j 30.5 33 1.6 31 1.3 Chloroform 0.19 80 0.53 LM I,1,2,2,-Tetrachloroethane 0.175 NL NL 11 2.7 1.8 Carbon Disulfide 0.3 NL 1000 NC 0.451 - - - Cis- 1,2-Dichlorocthene 70 70 61 NC _ 0.49J 69MW20D Trichloroethene (TCE) 2.8 5 0.028 CA Not installed 0.18j 0.47J 244.93 Chloroform 0.19 80 0.53 CA 0.181 - - Chloromethane 2.6 NL 1.5 CA 0.72J LM 41,2,2,•Tetrachloroethane 0.17 NL 0.055 CA - 0.75J UM= Upper Middendorf NC= Non -cancerous J= value Is esumntea Manse Jess than reporting ummt LM- Lower Middendorf CA= Cancerous J= value is estimated due to problems with quality control in lab. CF=Cape Fear NCs Non -cancerous U- same contaminant detected in trip or lab blank, value reported is too high. na= not analyzed. NS= Not Sampled UJ= analyte is not detected; however, detection limit may be inaccurate. Bold= exceeded NC 2L standards - Below Method Detection Limit or Not Applicable Table 4.2 (Oct, 2002) Summary of Laboratory Results for Ground -Water Samples Collected During Investigation of SWMU 69 (Cont) 69MW21D Tetraehlaroelhene (PCE) 0.7 S 0.66 CA Not installed 035j • - 036J 0.42J 231.45 Trichloroethene (TCE) 2.8 5 0.028 CA 70 269 51 20 1.11'1 Chloroform 0.19 80 053 CA 039j 0.413 Benzene 1.0 5 034 CA 2-Butanane 170 NL NL - 1.2-Diddoroethane 038 5 0.12 CA - 098 1,2-Dichloroethene NL NL - Carbon Tetrachloride 03 5 0.17 CA - - 038J Cis-1,2-Dichloroethene 70 70 61 NC - 0.623 i1,2,2-Tettaohloroethene 0.17 NL 0.055 CA 1.2 69MW21C Beazene 1.0 5 034 CA Not installed 0.47j 162.70 Chlomfmm 0.19 8o 0.53CA 0.29j CF Carbon Disulfide 700 NL 1000NC 0.403 Chloromethane 2.6 NL IS CA 0.443 69MW22C Tetrachloroethone (PCE) 0.7 5 0.66 CA Not installed 035J - - 166.95 7hehlottatheae (Try 2.8 5 0.028 CA 21 4.3 11 CF Chloroform 0.19 80 0.53 CA 030j - Carbon Tetrachloride 03 5 0.17 CA 0.19j Acetone NL' 610NC 3M 69MW22D Tetracldoroethene (PCE) 0.7 5 0.66 CA Not installed 0.15j 0303 - 252.48 Tricbloro-efiene(iCE) 2.8 5 0.028 CA 1.5 3.1 3.4 39 Chloroform 0.19 so 053 CA 1.1LM - - 1.1. eTetrachloroethane 0.17 5 0.055 CA 4.1 9.0 12 Cuban Disulfide 700 NL 1000 NC 0.44j Acetone NL 610 NC - 2.OJ YY�•+`y��•• �.-. uu+'+.ucrsuus j=Yarae r5 e6nmaten aeeause less Man reporting amrt LM Lower Mlddendart - CAS Culceroas J- value (s estimated due to problems wlth'quality control in lab . CF=Cape Fear NC- Non-eaaeerous U- same contaminant detected in trip or lab blank, value reported Is too blgb. aa= not atmlyzed. N3=Not Sampled UJ-analyte is not detected; however, detection limit may be luaccorate. Bold-erceeded NC2Lstsadards Below Metbod D etection Unsit or Not Applicable 1 � I Table 4.3 Ground -Water VOC Results from Temporary Wells SWMU 69 [Page 1 of 21 Location: Sample No.: Samplin Date: GW SCREENING LEVELS SWMU 69 691 W1 22 Aug. 01 SWMU 69 69TW2 23 Aug. 01 .; SWMU 69 69TW3 22 Aug. 01 SWMU 69 69TW4 23 Aug. 01 SWMU 69, 691W5 22 Aug. 01 1 SWMU 69 69TW6 22 Aug. 01 SWMU 69 697W7 22 Aug. 01 NC 2L Standard MCL Reg. 9 PRG Tap Water VOCs 8260B 1,1,2,2 Tetrachloro*thane µ9/L 0.17 NL 0.055 CA_ 0.52 J 7.9 - 3.3 - - 0.73 J 1,1,2-Trichloroothano µg/L NL 5 0.2 CA - - - - - - - 1,2-1111ichloroethane K9/L 0.38 5 0.12 CA - - - - --- 0.55 J ---- - - - -�- 2-Butanone µ9/1. 170 NL 190 NC - __ 1,6 - -- - -- 2.3 -- 12 Acetone pg/L 700 NL 61.0 NC 2.7 JB 4,3 J 1.2 JB 7.9 J - 52 EB - Benzene µ9/L 1.0 5.0 OA1 CA - - - - - 0.33 J - Carbon Disulfide µg/L 700 NL 100 NC - - 0.33 J - - 0.70 J 0.72 J Chloroform µ9/L 0.19 80 0.16 CA 0.78 J 0.56 J 0.34 J 1.4 0." J - 0.39 J Chloromethane µg/L 2.6 NL 1.5 CA 0.31 J - - - - 0.67 J 0.45 J cis-1,2-Dichloroethene µg/L 70 70 6.1 NC - 0.94 J - 0.42 J ONJ 2.4 Dichlorodifluoromethane µg/L 1,400 NL 39.0 NC 1.5 - - - - - Methylene Chloride µg/L 5 5 4.6 CA - - - 0.85 J_ - - - - - - 0.62 J - Naphthalene 21 NL 0.62. NC - _ - p-Isopropyltoluene Lim NL NL NL - - 1.2 - - - Tetrachloroetheno 0.7 5 1.1 CA - 2.1 1.9 1.2 - - 0.43 J Toluene 1,000 1,000 72.0 NC 1.6 3.1 0.60 J 2.0 0.59 J _ - - TriclNoroethene 2.8 5 1.6 CA 79 32 3.8 26 - 84 DATA QUALIFIER CODES: B = Not detected substantially above the level reported in laboratory or field blanks. E = Value detected Is above calibration range; value is therefore estimated. J = Indicates concentration is above method detection limits but below reporting limits. Concentrations are estimated values. NOTES (-) = Below Method Detection Limits NL = Not Listed CA = Cancerous NC = Non-canderous Table 4.3 Ground -Water VOC Results from Temporary Wells SWMU 69 [Page 2 of 2] SWMU 69 SWMU 69 69TW8 69TW9 22 Au . 01 22 Aug. 01 SWMU 69 69TW10 23 Au . 01 SWMU 69 69TW11 6 Feb. 02 SWMU 69 69TW12 6 Feb. 02 SWMU 69 69TW13 6 Feb. 02 SWMU 68 69TW14 6 Feb. 02 Location: Sample No.: Sam ling Date: GW SCREENING LEVELS NC 2L Standard MCL Reg. 9 PRG Ta Water VOCs (8260B) 1,1,2,2•Tetrachloroethane µg/L 0.17 NIL 0.055 CA 0.64 J - 1.2 - 4.1 3.5 1,1,2-Trichloroethane IuJIL NL 5 0.2 CA - - - 0.50 J - - 1,2-Dlchloroethane µg/L 0.38 5 0.12 CA 0.31 J - - - 2-Bulanone Acetone µg/L µg/L 170 700 NIL NIL 190 NC 61.0 NC - 0.38 JB - - - - - " 2.1 J - 2.1 J - 2.5 J - 1.7 J_ Benzene Carbon Disulfide Chloroform µg/L µg/L µ9/L 1.0 700 0.19 5.0 NIL 80 0.41 CA 100 NC 0.16 CA - OA8 J - 0.30 J - - - 0.41 J - - 0.88 J - - 0.60 J - - 1.3 0.31 J 0.59 J Chloromelhane µg1L 2.6 NIL 1.5 CA 0.36 J - ,_, �_ _ - - ___ - ds-1.2-Dichloroethene µgIL _70 70 -- 6.1 .NC � _ 1.2 _ _ Ti - 0.35 J Dirhlorodilluoromethane µg/L 1,400 NIL 39.0 NC - - - - - - - Methytene Chloride µg/L 5 5" 4.6 CA 0.37 J 0.50 J - - - - - Naphthalene µgh 21 NIL 0.62 NC - 0.49 J p4sopropylloluens Tetrachloroothene µgfL µ9n• NIL 0.7 NL 5 NL 1.1 CA - - - - - - 7.9 - 13 - 6.0 - 5.7 Toluene Trtchloroothene µglL 99l 1.000 2.8 1,000 5 72.0 NC 1.6 CA - 34 1.5 0.36 J - 2.4 - 62 - 41 - 22 - 90 DATA QUALIFIER CODES: B = Not detected substantially above the level reported in laboratory or field blanks. E = Value detected is above calibration range; value is therefore estimated. J = Indicates concentration is above method detection limits but below reporting limits. Concentrations are estimated values. NOTES: (-) - Below Method Detection Limits NL = Not Listed CA = Cancerous NC = Non-canderous Table 6.3 Historic Tetrachloroethene (PCE) Concentrations at SWMU 69 WELL NUMBER 2 L * (ug j) April 1995 August 1998 October 2000 August 2001 Sept. 2002 (Future Use) Concentration u/!) Concentration (URM Concentration u/1 Concentration n Concentration u Concentration u 69MW1 0.7 21.0 J 3.20 2.60 21.0 15 69MW2 ND 0.14 j ND ND ND 69MW3 ND 0.32 j ND ND ND 69MW4 Not Sampled Not Sampled ND _ ND ND 69MW5 ND 0.98 j ND ND ND 69MW6 ND 0.12 j 0.50 0.59 J ND 69MW7 ND ND ND ND ND 69MW8 ND ND ND ND ND 69MW9 ND ND 2.30 2.30 6.70 13 69MWI O 26.0 25.8. 25.0 32 69MWll Not Installed ND ND ND ND 69MW12 Not Installed 0.341 ND 0.32 J 0.42J 69MW13 Not Installed 0.211 ND ND ND 69MW14S Not Installed _ 0.27 j ND ND ND 69MW14D Not Installed 0.30 j ND ND ND 69MW15S Not Installed ND ND ND ND 69MW15D Not Installed 0.24 j ND 0.37 J ND 69MW16S Not Installed 0.45 j ND 0.37 J ND 69MW16D Not Installed ND ND ND ND 69MW17S Not Installed 24.0 15.5 25.0 21 69MW17D Not Installed 0.32 j ND 1.6 1.2 69MWISD Not Installed 0.30 j ND 0.37 J 0.40J 69MW19D Not Installed 0.15 j 2.5 2.9 4.1 69MW20D Not Installed ND ND ND ND 69MW21C Not Installed 0.47j ND ND ND 69MW21D Not Installed 0.35 j ND 0.36 0.42J 69MW22C Not Installed Not Installed 0.35 i ND _ ND ND 69MW22D 0.15 i ND 0.30 J ND *2L is Based on NC.21, Groundwater Protection Standards ND = Not Detected j = Value is estimated because it is less than the reporting limit. J = Value is estimated due to problems with quality. control in lab. Table 6.4 Historic Trichloroethene (TCE)'Concentrations at SWMU 69 WELL NUMBER 2 L * (ug/1) April 1995 August 1998 October 2000 August 2001 September 2002 (Future Use) Concentration (ugn) Concentration (ugn) Concentration (n ) Concentration (ugn) Concentration (n 1) Concentration (ug/1) 69MW1 2.8 •25.0 J 5.20 6.80 42.0 13 69MW2 UJ 0.33 j ND 1.80 1.4 69MW3 ND 0.22 j ND ND ND 69MW4 Not Sampled Not Sampled ND ND Not Sampled 69MW5 6.2 0.25 j ND ND 2.3 69MW6 89.0 26.0 51.0 75.0 91 69MW7 ND ND ND ND 2.0 69MW8 ND ND ND ND ND _ 69MW9 24.0 0.74 j 0.50 0.84 J 1.2 69MW10 19.0 23.0 35.5 18.0 5.9 69MW11 Not Installed ND ND ND ND 69MW12 Not Installed 42.01 28.3 30.0 28 69MW13 Not Installed 1.10 ND ND 0.46J 69M MS Not Installed 5.10 3.90 7.50 ND 69MW14D Not Installed ND ND ND 5.6 69MW15S Not Installed ND ND ND ND 69MW15D Not Installed 0.41 j ND 0.48 J 0.36J 69MW16S Not Installed 7.30 7.80 20.0 19 69MW16D Not Installed 0.19 j ND ND ND 69MW17S Not installed 9.10 J 3.20 4.80 4.4 69MW 17D Not Installed 7.80 ND 2.10 0.51 J 69MW18D Not Installed 49.0 45.7 49.0 38 69MW19D Not Installed 18.0 30.5 33.0 31 69MW20D Not Installed 0.18 j ND 0.47 J ND 69MW21C Not Installed ND ND. ND ND 69MW21D Not Installed 70.0 26.9 51.0 20 69MW22C Not Installed 21.0 ND 4.30 11 69MW22D Not Installed 1:50 3.10 3.40 3.9 *21, is Based on NC 2L Groundwater Protection Standards ND = Not Detected j = Value is estimated because it is less than the reporting limit. J = Value is estimated due to problems with quality control in lab. UJ = Analyte is not detected; however, detection limit may be inaccurate. r' r Table 6.5 Historic Chloroform Concentrations at SWMU 69 WELL NUMBER 2L * (ug/1) April 1995 August 1998 October 2000 August 2001 Sept: 2002 (Future Use) Concentration NO) Concentration u /1 Concentration (n Concentration u Concentration u Concentration u /1 69MW1 0.19 ND 13.0 j ND 0.43 J 0.36J 69MW2 ND ND ND ND ND 69MW3 19.0 U 0.46 j ND 6.2 2.4 69MW4 ND ND ND ND ND 69MW5 ND ND ND ND ND 69MW6 ND ND 0.21 j ND 0.74 1.0 69MW7 0.80 j ND 4.00 2.0 69MW8 ND ND ND ND ND 69MW9 7.90 0.34 j ND ND 0.33 69MW10 ND 1.20 0.60 0.53 J 0.43J 69MW11 Not Installed 0.14 j ND ND ND 69MW12 Not Installed 0.56 J ND 0.37 J 0.47J 69MW13 Not Installed 0.22 J ND ND ND 69MW14S Not Installed 0.16 j ND _ ND ND 69MW14D Not Installed 0.22j ND _ ND 5.6 69MW15S Not Installed ND ND ND ND 69MWISD Not Installed 0.14 j ND 0.383 0.40J 69MW16S Not Installed 0.30i ND 0.67J 0.64J 69MW16D Not Installed 0.36 j ND 0:40 J 0.38J 69MW17S Not Installed 3.60 J 5.00 4.50 3.1 0.82J 69MW17D Not Installed 0.37 j ND 0.66 69MW18D Not Installed 0.50 j ND 0.36 J 0.38J 69MW19D Not Installed 0.92 j ND 1.60 1.3 69MW20D Not Installed 0.18 j ND ND. ND 69MW21C Not Installed 0.29 j ND ND ND 69MW21D Not Installed 0.39 j ND 0.41 J ND ND 69MW22C Not Installed 0.30 i ND ND 69MW22D Not Installed 1.1 ND ND ND *21, is Based on NC 2L Groundwater Protection Standards j = Value is estimated because it is less than the reporting limit. ND = Not Detected J = Value is estimated due to problems with quality control in lab. U = Same contaminant detected in trip or lab blank; value reported is too high. Table 6.6 Historic Dieldrin Concentrations at SWMU 69 WELL NUMBER 2L * (ug/n April 1995 August 1998 October 2000 August 2001 (Future Use) (Future Use) Concentration u Concentration u Concentration u Concentration u /1 Concentration (ug/1) Concentration u 69MW1 0.0022 0.12 <0.10 UJ Not Sampled Not Sampled 69MW2 UJ , <0.10 UJ Not Sampled Not Sampled 69MW3 ND <0.10 UJ Not Sampled Not Sampled 69MW4 Not Sampled Not Sampled Not Sampled Not Sampled 69MWS ND <0.10 UJ Not Sampled Not Sampled 69MW6 ND <0.10 UJ Not Sampled Not Sampled 69MW7 ND <0.10 UJ Not Sampled Not Sampled 69MWg ND ND Not Sampled Not Sampled 69MW9 ND 0.36 j Not Sampled Not Sampled 69MW10 ND <0.10 UJ Not Sampled Not Sampled 69MW11 Not Installed Not Sampled Not Sampled Not Sampled 69MW12 Not Installed Not Sampled Not Sampled _ Not Sampled 69MW13 Not Installed Not Sampled Not Sampled Not Sampled 69MW14S Not installed Not Sampled Not Sampled Not Sampled 69MW14D Not Installed Not*Sampled Not Sampled Not Sampled 69MWISS Not Installed Not Sampled Not Sampled Not Sampled 69MWISD Not Installed Not Sampled Not Sampled Not Sampled 69MW16S Not Installed Not Sampled Not Sampled Not Sampled 69MW16D Not Installed Not Sampled Not Sampled Not Sampled 69MW17S Not Installed Not Sampled Not Sampled Not Sampled 69MW17D Not Installed Not Sampled Not Sampled Not Sampled 69MW18D Not Installed Not Sampled_ Not Sampled Not Sampled 69MW19D Not Installed Not Sampled Not Sampled Not Sampled 69MW20D Not Installed Not Sampled Not Sampled Not Sampled 69MW21C Not Installed Not Sampled Not Sampled Not Sampled 69MW21D Not Installed Not Sampled Not Sampled Not Sampled 69MW22C Not Installed . Not Sampled Not Sampled Not Sampled 69MW22D Not Installed Not Sampled Not Sampled Not Sampled *2L is Based on NC 2L Groundwater Protection Standards ND = Not Detected j = Value is estimated because it is less than the reporting limit. US = Analyte is not detected; however, detection limit may be inaccurate. Table 8.1 Ground -Water Geochemical Data, September 2002 WELL NUMBER Chloride (mg/L) CO2 (mg/L) ORP DO pH Conductivity Temperature Turbidity 69MW1 5.5 84.0 453 4.71 3.7 38.8 19.8 63 __ 69MW2 5.0 36.0 476 7.0 3.63 63/7 22.8 14.0 69MW3 5.0 45.0 514 5.78 2.07 57.1 24.8 170 69MW4 dry dry dry dry dry dry dry dry 69MW5 4.5 52 na 6.87 3.51 4.22 _.r.. 39.9 44.0 19.6 20.65._..._.I.___ 11.3 15.1 69MW6 5.0 70 475 4.3 69MW7 8.8 76 457 6.91 4.81 86.1 21.6 97.1 69MW8 1.5 69 6 0.87 6.74 140.9 20.9 6.63 69MW9 4.5 92 430 7.99 3.6 39.4 19.7 10.2 69MW10 6.0 44 445 5.52 4.36 46.5 151 37.3 19.9 19.7 69MW11 69MW12 na 7.0 na 44 263 487 6.17 6.34 4.51 2.61 19.3 28.1 1000 48.2 69MW13 3.0 40.5 360 3.79 4.27 23.0 20.39 194 69MW14S 3.0 68 487 499 3.56 17.7 20.1 1000 69MW14D 4.5 51 466 4.97 3.56 20.6 21.9 123 69MW15S 4.0 72 398 6.01 4.67 31.0 25.41 r ]9.83 31.4 69MW15D 7.0 54 254 6.57 6•Z-89.6 18.7 69MW16S 7.5 44 436 4.7 3.71 54.1 19.2 219 69MW16D 11 1 34 444 4.03 4.43 67.4 18.7 30.5 69MW17S 6.0 52.5 490 5.9 303 47.8 20.7 1000 69MW17D 7.0 32 183 4.75 4.91 103.3 I 20.5 22.1 69MW18D 6.5 40 529 617 2.44 44.4 18.8 74.1 69MW19D 5.5 40 505 6.78 1.54 43.2 19.1 9.82 69MW20D 2.5 34 399 4.23 4.35 16.3 18.5 58.1 69MW21C 1.5 30 150 1.73 4.91 120.5 21.17 179 69MW21D 5.5 84 411 4.06 4.01 36.1 1 9. 4 21.2 627 69MW22C 2.0 10 24 3.03 9.87 397.9 51.2 69MW22D 3.8 1 54 459 6.12 3.88 459 24.8 29.7 E� Table B-1: Analytical Results from Ground -Water Sampling Event, June 2004, SWMU 69, Fort Bragg, North Carolina well Results Number Analyte NC 2L Region 9 4/1"S 811998 1012000 8/2001 9/2002 6/2004 Ground- Ground M PRG (Method 8W, (Method (Method Method 8260, Method 8260, Method water water Tap Reporting 8260, 8260, Reporting limits Reporting limits 8260, Elevation Protection C Water limits for Reporting Reporting for TCE/KE - for TCE/PCE - Reporting 8/2001 STDS L (2004) TCE/PCE-5.0 limits for limits for 1.0 ug/L) 1.0 ug/L) limits for (ugn) ut�) TCE�; - 1.0 1.0 ug/L) 00.5 ug/L)E. u (u1;n) 69MW10 Tetrachlomethene(PCE) 0.7 5 0.66 26 25.8 25 32 9.0 252.83 Trichloroethcne (TCE) 2.9 5 0.028 19 23 355 18 53 11.0 Chloroform 70 80 0.17 - 1.2 0.6 0.53J 0.43J 2.7 UM Bis(2-ethylhexyl)pthadate ' 3 6 4.8 1.8j Dieldrin 0.0022 NL 0.0042 <0.IOUJ na - - 69MWll Benzene, 1.0 5 0.35 Not Installed 0.54j - 232.56 Chloroform 70 80 0.17 0.14j - - Chloromethane 5 5 160 0.44J UM Acetone 700 NL 5500 2.9J 2.4 69MW12 Tetrachlomethene (PCE) 0.7 . 5 0.1 Not Installed 0.34J - 032J 0.42J - 241.26 Trichlomthene (TCE) 2.8 5 0.028 42J 283 30 28 28 LM Chloroform 70 80 0.17 0.561 037 0.47J - Benzene 1.0 5 0.35 0.17J 0.65 2-Butanone 170 NL 7000 0.84J - 1,2-Dichlaroethane 700 5 0.12 0.17J 1,1-Dichloroethene NL 340 1.6J 0.95J Carbon Tetrachloride 0.3 5 0.17 0.21 J Chlorometime 5 5 160 0.591 - Cis-1,2-Dichlormthene 70 70 1 61 0.74 1.1 69MW13 Tetrachlomethene(PCE) 0.7 5 0.1 Not Installed 021.1 well Trichlomethene (TCE) 2.8 5 0.028 1.1 0.46J - broken Chloroform 70 80 0.53 0.221 Benzene 1.0 5 0.35 IA LM Ethylbenzene 29 700 1300 1.2U Chloromedme 2.6 NL 160 0.111 0.891 Methylene Chloride 5 5 4.3 1.6 69MW16 Tet achlomethene (PCE) 0.7 5 0.1 Not installed 0.45j 037J S.Trichlomethene (TICE) 2.8 5 0.028 73 7.8 20 23 Chloroform 70 80 0.53 0.30j 0.67J L 0.40 251.42 Chloromethmute 2.6 NL 160 0301 0.81 UM Cis-1 -Dichloroethene 70 70 61 0.61J 0.95 69MW16 Tetrachloroethene (PCE) 0.7 5 0.1 Not installed - - D Trichloroethene(TCE) 2.8 5' 0.028 0.19j - - - Chloroform 70 80 0.53 0.36j 0.401 0.38J 0.41J 250.40 Carbon Tetrachloride 03 5 0.17 0.31j - 0.45.1 OJOJ LM 1-Dichloroethane 038 NL 0.12 0.59i 1.0 0.61J 0.681 69MW18 Tetrachloroethene (PCE) 0.7 5 0.1 Not installed 0.30j - 0.37J 0.40J 0.433 D Trichlomethene (TCE) 2.8 5 0.028 49 45.7 49 38 38 240.80 Chloroform 70 80 0.17 0.5% 0.36J 0.38J 0.521 Carbon Tetrachloride 0.3 5 0.17 0.15J LM 1,2-Dichloroethane 0.38 5 0.12 0.27 0.44.1 0.55J 4-Methyl-2-pentanone NL NL 0.85j - Chloromadme 5 5 160 0.82J 1,1,2,24etrachloroethane 0.17 NL 0.055 038J 0.511 0.W Cis-1.2-Dichlomethene 70 70 1 61 1.2 1.3 1.3 69MW19 Tetrachloroethene (PCE) 0.7 5 0.1 Not installed 0.75J 2-5 29 4.1 2.4 D Trichloroethene (TCE) 2.8 5 0.028 IS 30.5 33 31 28 239.17 Chloroform 70 80 0.17 0.92j 1.6 1.3 IS 1,1,2,2, Tetrachloroethanc 0.175 NL NL 11 2.7 1,8 1.9 LM Cuban Disulfide 03 NL 1000 0.45j Cis-I-Dichlorocthene 70 70 61 0.49J OA3J 69MW20 Trichlotnethene (TCE) 2.8 5 0.028 Not installed 0.18j 0.47J D Chloroform 70 80 0.17 O.l8j - - 244.93 Chloromethane 2.6 NL 160 0.72J - 1,1,2,2,-Tetrachloroethane 0.17 NL 0.055 - 0.75J LM Naphthalene' 5.0 5 160 - 0.59.1 Methylcne-Chloride 5.0 5 4.3 0.33.1 69MW21 Tetrachlomethene (PCE) 0.7 5 0.66 Not installed 0.35j 0.36J OA2J D Trichloroethcre (TCE) 2.8 5 0.028 70 26.9 51 20 30 231.45 Chloroform 70 80 0.53 0.39j - OAIJ 0.343 Benzene 1.0 5 0.34 - LM 2-Butanonc 170 NL NL - - - 1,2 Dichloroethanc 0.38 5 0.12 0.98 0.521 1,1-Dichlomcthcne NL NL Carbon Tetrachloride 0.3 5 0.17 038J Cis-1.2-Dichloroethene 70 70 61 0.62.1 1.2 1,1,2 -Tetrachloroethane 0.17 NL 1 0.055 - 1.2 69MW21 Benzene 1.0 5 0.34 Not installed 0.47j - - C Chloroform 70 80 0.53 0.2% - - - 162.70 Carbon Disulfide 700 NL 1000 0.40,1 Chloromethane 2.6 NL 1.5 0.44.1 CF 69rdW22 Tetrachloroethenc (PCE) 0.7 5 0.1 Not installed 0.15j 0.30J - D Trichloroethene (TCE) 2.8 5 0.028 1.5 3.1 3.4 3.9 1.7, 252.48 Chloroform 70 80 0.17 1.1 - - - 0.33J 1,1,2,2,-Tettachloroethane 0.17 5 0.055 4.1 8.0 12 6.2 LM Carbon Disulfide 700 NL 1000 0.44j Acetone I I NL 1 3500 - 2.0J � b o 69MW22 Tetrachloroethene (PCB) 0.7 5 0.1 Not installed 0.35j - - - C Trichlomethene (TCE) 2.9 5 0.028 21 4.3 11 3.6 166.95 Chloroform 70 80 0.17 030j - Carbon Tetrachloride 0.3 5 0.17 0.19j CF Acetone NL 5500 3.O1 3.2J13 69TMW23 Carbon Disulfide 700 NL 1000 No No No No No 1.2 Methylene Chloride 5 5 160 Sample Sarnple Sample Sample Sample 0.541 69TMW24 7iichloroethene 2.8 5 0.028 No No No No No 18 Methylene Chloride 5 5 160 Sample Sample Sample Sample Sample 0.19.1 Chloroform 70 .80 0.17 0.54.1 1.2-Dichlor+oethane 0.38 5 0.12 0.37) 69TMW25 Trichloroethene 2.8 5 0.028 No No No No No 14 Cis-1,2-Dichloroethene 0.28 70 61 Sample Sample Sample Sample Sample 0.82•l Chloroform 70 80 0.17 0.49.1 Surface Water 69SW7 All ND No No No No No All ND Sample Sample Sample Sample Sample 69SW8 All ND No No No No No All ND Sample Sample Sample Sample Sample 69SW9 All ND No ' No No No No All ND Sample Sa le Sample Sample Sample Table B-2: Monitoring Well / Piezometer Details 0 WeRIPlezometer ID Formation Easting Northing Top of Casing Elevation (ft) Depth to Water (ft) Ground -water Elevation (ft) MW-1 UM 2004928.39 "-,511201.51 292A9 38.74 253.75 MW-2 UM 2004774.58 510941.32 291.98 37.34 254.64 MW-3 UM 200S176.37 510965.77 29S.24 NM NM MW-4 Perched 2005128.98 511300.55 291.64 6.05 285.59 MW-5 UM 2004702.54 511242.92 288A8 NM NM MW-6 UM 200-4933.72 511559.27 286.54 33.99 252.55 MW-7 UM 20W94.43 511113.35 288.85 34.82 254.03 MW-8 CF 2004450.81 511195.36 287.5 >102.0 NA MW-9 UM 2004918.43 511199.49 292.31 38.63 253.68 MW-10 UM 2005132.71 511294.55 290.97 37.86 253.11 MW-11 UM 2005623.56 513182.33 251.52 18.15 233.37 MW-12 LM 2005048.88 512575.49 257.48 15.40 242.08 MW-13 LM 2005658.75 512755.81 245.85 9.90 WAS MW-14S UM 2004928.28 511352.S5 290.42 37.00 253.42 MW-14D LM 2004923.68 511350.73 290.38 39.78 251.60 MW I5S UM 2004546.31 511907.31 278.68 20.10 2S8.58 MW 15D' LM 2004547.76 511901.59 279.12 28.00 251.12, MW-16S UM 2004888A8 311916.63 278.12 26.26 251.86 MW-16D LM 2004903.18 511815.95 277.75 27.00 250.75 MW-17S UM 2005311.81 1 511728.31 272.72 21.42 251.30 MW-17D LM .:2005311.58 1 S11734.57 273.04 22.34 250.70 MW-18D LM 2005047.39 1 512569.44 257.81 16.33 241A MW-191) LM 2005529.50 512303.52 249.1 8A2 240.68 MW 20D LM 2006192.18 512383.72 262.63 .16.75 245.88 MW-21C CF 20DS617.24 513195.96 252.67 88.15 164.S2 MW-21D LM 2005625.94 513176.95 251.4 1991, 231.49 MW-22C CF 2005051.97 510723.42 293.27 71.02 222.25 MW 22D LM 2004970.79 510812.94 296.48 4336 253.12 P-1 UM 2006222.33 1 511842.35 270.98 24A9 246.49 P-2 UM 2005798.70 1 11445.69 .267.85 NM NM P-3 UM 200573155 . 511845.25 246.66 - 2.28 244.38 P-4 UM 2005740.23 51246259 241.02 0.93 240.09 P S UM 2005371.22 511408.57 269.23 17.15 252.08 P-6 UM 2005471.40 511721.12 254.43 3.65 250.78 P-7 UM 2005636.88 511865.78 254.24 5.74 248.50 P-8 UM 2005463.01 51308557 257.11 23.25 233.86 P-9 UM 2005163.14 511481.29 283.78 31.52 252.26 P-10 UM 2005369.03 511868.19 271.73 NM NM P-1I UM 2005155.27 512180.79 271.69 NM NM P-12 UM 2005278.29 512400.05 271.11 30.64 240.47 P-13 UM 2005169.10 517749.65 261.31 19.02 242.29 - P-14R UM 2005001.10 511653.10 283.36 31.20 252.16 P-17 UM 2004379.99 512871.68 269.38 24.01 245.37 P-18 UM 2004623.72 513023.95 268.47 23.00 245.47 P-19R UM 2004663.70 511539.10 283.19 30.07 253.12 P-20 UM 2004589.74 511900.38 274.61 15.60 259.01 P-21 UM 2004809.76 512567.50 273.01 26.95 246.06 P-22 UM 2004617.49 512147.85 270.74 23.20 24754 P-23 I UM 20D4204.50 513227.64 251.7 9.75 241.95 P 24 I UM 2004350.97 512464.06 281.5 35.14 24636 P-25 I UM 2005426.50 512043.80 271.15 20.49 250.66 nu geograpmc coorountes used m tms more are rommea to Nona c4rotwa btate rune reef, NAD 83 All elevations used in this table are referenced to feet above Mean Sea Level UM = Upper Middendorf LM - Lower Middendorf CF = Cape Fear NM - Not Measured ''A. — �i ��j q I l : (' I i�uNtaD I \\ ^ j� P `� . r ✓��` �)n(/`/�J] . �FV li SJ�' OP-4 .,\�• tteM'tt - ., ��`c(,\ IS� `t 'uJ ��Y ��. ` �Y, i,�� 1 mID - :� ttOTN10 P- eii aN (t ~i�gaf - • ,'\� { �} ' � cOy % � % i Az>ta�90 '�. \ •'air 2 J '�\ \ 11y� / tma0 �p . `P' ._ "Fit'{ I .•. �wvB 2 , :,•;� ,`•Or�m 'j67riHoeo ��• ,\ •`I / 10 TI 31 1 3W.' 0. .300 GOT �J n 117f]c 69Mt LEGEND _ - .SCALE IN FEET ' ' a w a• o er1 ®wMONITO{UNG WELL(ACATONS `DP ��'� - / 1/ •,w.emawmwcc ua.0 •:. WATER LEVEL ELEVATIONS. . PIQOAtETER� C 0. I O _ - R. SPADD GI9 .. M. . SURFACEWATERSANPLE LOCATIONS �+ AREA OF GROUt'UYWATER HOUNDING^�' (% GROUND -WATER CONTOUR LINE 0 0 � C *'3 POTENTOMERIO SURFACE . TOPOGRAPHIC CONTOUR LINES JUNE14.7001. . —I36.0� GROUMMATER CONTOUR LINES IOASHEOINHEREAPPROXIFAAT-j CI=2 e c e `1�Ia.W�.. ...srmsa. �n� Flourte flypA 4 7 a 266.89 264.42 i 22D 89 264.44 /' �12MW3 � Y 89TMW23D aDswo ov fj z I1 I l 300' 0 309 600, SCALE IN FEET 69Mw1 LEGEND 0 MONITORING WELL LOCATIONS U.9.ARWENGlNMRDI3M CT, 3AWWNAN 252 WATER LEVEL ELEVATIONS �3AVVA OMA • PIEZOMETER FT. BRAGG CMS ■ SURFACE WATER SAMPLE LOCATE SWMU-68 GROUND -WA ER CONTOUR LINE POTENTIOMETRIC SURFACE -- TOPOGRAPHIC CONTOUR LINES i JUNE 14, 2004 — 235.0 --- GROUND -WATER CONTOUR LINE; FT. BRAGG NORTH CAROLINA (DASHED WHERE APPROXIMATE) (2c.dgn DATE: May 20M 1 1FIGURE E►pp B G35 •. o n �� F 18 `� (6^ ■ a 037 •34 � s . � 1 � tl- i . - _. . \ V G Y ( -� 2ft7M - \' ,i G39 . low) SCALE IN (FEET �.. _ '�, u. a. �rvetsr�xooannct: maviwa� -� •� �^ c0RkaFWMM3W . aAVMiWt alumm .. SMAU-M HORIZONTAL DISTRIBUTION OF �• �\ l'•^ UY6YNE 23iiSi'9 u.. .ty - ,... DATE 31Fsy 2Dap �d�t9� �Awe, APPENDIX B HUMAN HEALTH RISK ASSESSMENT TABLES C� C-1: Ground Water Data Sat- All Constiumnts ldenWWd as COPCs srI@:swMU49 FacUlty: Ft. Bragg.NC ID IPWMNW Ru&uW lab Quaffier Rk3NNs Wis SWMU419 ugJL -1 PC 15.00 15A0 PAW-2 PCE 1.00 U 0.50 u NW-3 PCE AO U 5050 MW5 E 1.00 U 0.50 -0 M PCE 1.00 U 0.50 u MW- PCE 1.00 U 0.50 UWL W-9 PC 13A0 13.00 MW-10 .00 32.00 MW-1 1.00 U 0.50 L MW-12 PCE 28.00 28.00 MW43 1.00 U 0.50 MVV-1 SS PEE 1.00 U 0.50 M -140 FCE 1.00 U 0.50 MW15S E .00 U 0.50 M -i5D ME 1.00 U 0.50 -185 1.00 0.50 u MW-ISD PCE 1.00 U 0.50 MW-175 PC§ 21.00 21.00 M •tTD PCE 1.20 1.20 u mW-16D E 0.40 J 0.40 -190 4.10 4.10 UWL •21D D. J 0.42 Av D.bOtad V.I..: .at UWL asMum DatsOtad Valor 32ao UGIL MC 2 L Standards 0.70 LKA Prellintrim Ramadlatbn OW: sea UWL Ia1D P Result Lab Quallfter RA Value Unka 3WMLldn QWL MW-1 chwdonn 0.38 J 0.350 UWL MIN-2 CMaOtam 1.00 U 0.50 UWL MW-0 M*Ydorm 2.40 U 0.W MW5 Chloroform 1.00 U 0.5D UPJL MW-0 Chbr&orm 1.00 1.00 uWL -7 Chimdam 2.OD 2.00 LWL fjw-9 chloworm 120 . 1.21) MW-10 cAdom 0.431 J OA3 uan- mw-II ChlorO/orm 1.001 U 1.00 umfL MW-12 0.47 0.47 UPJL MW-13 Chwdwn 1.00 U 0.50 UDIL -14S CtJadono 1.00 U 0.W UWL -14D chlordarm 50 5.80 QwL DW-15-S Chlwdoem OAD J 0.40 UWL MW-150 GrAorworm 0.40 J 0.400 uafL MW-155 0.54 J 0.040 MW-18D omt 0.38 J 0.380 MW-17S Ctilmdorm 3.10 3.10 unr M -17D COlardorm QAZ J 0.82 1AW-180 Chwdbrm 0.38 J 0.38u M -1a0 Ctwrokffn 1.30 1.30 MW-210 am 1.00 U 0.50 Av aWa: 1.a3 la.al.wm Daiacbd Value: 0.00 RC 2 E- standards 70ao Pralbnbu Ranlad[Mkn Goal: 0.17 SAMPIS ID PararOaw Result LabGualMw RA Value UnOs SWMIW Y MW-1 TCE 13.00 1&00 MW-2 TCE 1.00 U 0.50 UIA MW-3 TCE t.40 1.40 UWL Mw5 TCE 2.30 2.30 LrWL MW8 TCE 01.00 91.00 uwL M -7 TCE 2.00 2.00 MW-9 TCE 1.20 1.20 ula M AO TCE 5.901 5.90 UWL MW-11 TCE 1.00 U 0.50 UWL MW-12 TCE 28.00 25.W UWL MW-13 TCE 0.48 J 0." UOIL MW-14S CE 1.00 U 0.60 MW-140 TCE 1.00 U CAW uwI MW-15S TCE /.00 U 0.50 Lot MW-15D TCE 0.33 J - 0.9E LKA MW18S TCE 19.00 19.00 UwL MWtOD TCE 1.00 U 0.50 ugx MN-17S TCE 4.40 .40 MW-170 TCE 0.51 J 0.51 MW-180 TCE 38.w311.00 UJwL MW-190 TCE 31.00 91.00 MW21D TCE 20.00 20.00 Aran . W0a01ad Valve: 11At max m rn Doodad Value: 1111 NC2LMmdwft 2.6 prollmilmy Remo latWrl000'.t 0.9211 Sam N 1D Paramabr Raven Va1us[ Unho WMLt49 u MW-1 /.1.2.2TeCA 1.000.50 UWL MW2 1.12.2TOCA 1.00DAD LKA MW-3 /.1.2.2TOCA 1.000.50 MW5 1.1.2.2TOCA 1.000.50 MW-0 1.1.22 TOCA 1.001 U 0.Ou MW-7 1.1.2.2•TOCA 1.00 U 0.50 MW-D 1.122 TOCA COD U 0 NW10 1.12.2T 1.00 U 0.50 MW-11 1.1.2.2•T 1.00 U 0.60 UWL MW-12 1.1.2.2 TaCA 1.00 U 0.50 uafL MW-13 1.1.2.2-T 1.00 U .60 MW-043 1.1.22-TOGA 0.40 J 0.40 MIN-14D 1.122 TOGA 1.00 U 0.50 MW-15S 1.12.2-TOCA 1.00 U 0.50 UWL MW-15D 1.1.2.2TOCA 1.00 MIN-0OS 1.122 T 1.00 U 0J50 MW-16D 1.1.2.2-T 1.D0 MW-175 1.12.2TOCA 1.00 U 0. MW-17D 1.1.2.2- 0.85 J Oaa MIN-18D. 1. 22-T 0.51 J O8t MW-19D 1.12.2T 1.60 t.54 MW-21D 1.12.2- 1.20 1220 A1rar Detected Valua: 0as uWL Maslmum V., 140 NC 2 L standards o.17 PrslMn ROmWlallon GOai• OMB I UGIL C-2: Summmary and Exposure Point Concentrations of Selected Chemicals of Potential Concern (COPC) Site: SWMU 69 .Facility: Ft. Bragg, NC Surface Subsurface Residuum Soil Soil Groundwater Chemical mg/kg mg/kg mg/L Oroanics PCE ---- — 0.0055 TCE ---- --- 0.0115 CHLOROFORM --- ---- 0.00105 1,1,2,2-TETRACHLOROETHAN E — -- 0.00059 U � o IWAII.Wigulwl YYIUW3 - - TO)OCOLOGICAL DATA FOR ORGANIC COMPOUNDS SFd RfDd Sfo R(Do - SFI . RID! CAS No. 1! m -d m wd) 1! m -d m -d 1! m m d PCE 5.40E-01 na - c - 5.40E 01 , -- na c: 2.10E-02 1:00E-02 c .' 7: 7184. TCE---: -7.3E-02 . na' a 130E-02 na _ s 6.0E-03. .1.70E-01 a 74016' Chloroform na 0.002'. _ i na na a 8.1E-02 na: i 67663 " t 1 2 -TOCA 0 288 na i.: " . 0.2: _ na . I 0.203 . na- f . : 79345 - Chemical Values CONTAMINANT :. PHYSICAL CHEMtCAL.DATA FOR .VOLATILE COMPOUNDS. qC rrrol .. dimensloriless . cm=/s cm2/s - cm'/ em'/ m L-water (4uL.J (L-wI-1) (cam) - s .- - m=-s PCE' :. 165.83 0.7240000' 72E-02 -.82E-06 108800. 2.1E+02 0.284 0:15 0.05 9.50E+08 . 77.08 TCE - 131.39 0.4020000' 7.9E-02 . 9.1E-06 .: 67700: 1.3E+03 - 0.284• 9:50E+08 - 77:08 Chloroform 119.38 : ° .110,00 ` 10E-01 35040 B:OE+03' 0.254 0.16. 0.02 9.50E+08 77.08-: 1 1 2 2-1 eCA " ` .. 16T.85' 0.0150000 7.1E-02 7:9E-06 . 106ao 2.9E+03 ' 0:284 7. 0.15 - . '0.02 . 9.50E+08 77.OB CONTAMINANT " V (unitless) U I ..... (m%s) U- . (m/s) PHYSICAL CHEMICAL DATA FOR VOLATILE COMPOUNDS F(X) 11py p..: D, .. (unitlws) ., _ � J (�cm�) (Fl y) . (9/ ) : (cmf/s). VF . (m3/kB) PEF (m"/W SAT (Mg/kg) PCE 0.5 '. 4.69 11:3 0:194 D.434 9.5 . ' 2.65 6.0E=03" 1.17E-D2 1.30E+03 1.12E+09 4.9E+01: TCE 0.5 4.69 11.3. Os194 - 0.434 1.5 2.65 - 6.0E-03 9.61E-03. : 1.43E+03 1.12E+09 . ' -2.3E+02 Chloroform 0.5 4.69 11.3 ' 0.194 0.434=: 1:5 2.65 - 6.0E-03 6.47E-03 1.74E+03 1.12E+09 1.0E+03 192246CA• : 0.5 ':4.69.. .'- 11:3•. 0.194'•• 0.434 . 1,5 2.65: - 6.0E-03 5.52E-04 6.05E-OZ 1.12E+09 :- 3.0E+02 - TOXICOLOGICAL DATA FOR ORGANIC COMPOUNDS SFd . RfDd . Sfo :.. RfDo" - SFi .. 1/ m m -d 1/ m m k 1/ m k -d RfDL . CAS No. ni PCE na , na n na. na . n 0.016 n TCE na • na,.. n na . _ . ... na : n- na .. 0.00171 n . Chloroform : 2.0E-03 :. 0.002. na = 1.00E-02 ' 1. : 8:1E-02 . na : . 1 671%3 CONTAMINANT MW. mol :.dimensionless Dt cmT/s PHYSICAL CHEMICAL DATA FOR ORGANIC COMPOUNDS DW S' . . 88W cm:/s cm'/ cm'% m -watei (I.�1-�'�.. (L.A. ( ) T. s Q/C . '-s m, PCE 165-83 0.7240000 .. 7 2E-02 82E-06 . - _ 106800 : 2.1E+02 0.284 0.15 .. 0.05.' ."- 9:50E+08 . 77.08 TCE-131.39 0.40200020 7.9E=02' 9:1E-06 67700 1.3E+03 0284. .. 0.15 .6.02 9:50E+08 77.08 .. Chloroform 119.38 1 1 0.1500000- I 1:0E-01. 4.0E-05. - 35040 1 &OE+03 0284 0.15. 0.02 1 9.50E+08 77.08 CONTAMINANT V (unitless) U. nt/c U. (m/s) PHYSICAL CHEMICAL DATA FOR ORGANIC COMPOUNDS F(x) n.- pp palfQ D. (unidess) . . (p/cm�).. (F,/an�) (0/9) (time/s VF (ms�6) - PEF (m'h8):.. SAT (m PCE 0.5 4.69 11:3 0.194 - 0.434 1.5 2.65' . 6.0E.03 1E•02 1 +03. 1:12E+09 5E+01.. _ TCE: 0.5. 4.69. 11.3 0.194. 0.434 1:5 2.65 6.0E-03 1E-02 1E+03 1.12E+09 :.2E+02 Chloroform 0.5 .4.69 - 11:3- 1 0.194 1 0:434' 1 1.5 2.65 1 6.0E-03 I 6.47E-03 1.74E+03 -1.12E+09 1.0E+03 . I = iris 04: Summary of RM E Incremental Lifetime Cancer Risks and Noncancer Hazards - All Selected Receptors Site: SWMU-09 Facility: Ft. Bragg, NC Summary of RME Cancer Risks Current Land -Use _ Future Land -Use Surface Subsurface Total Total Soil Soil Groundwater Site Site Receptors ILCR ILCR ILCR ILCR ILCR On -Site Resident (adult)' NA NA 3.93E-05 NA 3.93E-05 On -Site Resident (Child) ° NA NA 1.47E-05 NA 1.47E-05 Installation Worker ° NA NA 1.14E-05 1.14E-05 1.14E-05 Current Land -Use Total Site ILCR 1.14E-05 Future Land -Use Total Site ILCR 8.54E-05 Summary of RME Noncancer Hazards Current Land -Use Future Land -Use Surface Subsurface Total Total Soil Soil Groundwater Site Site Receptors Hl HI HI HI HI On -Site Resident (adult)' NA NA 0.020 NA 0.020 On -Site Resident (Child) ° NA NA 0.008 NA 0.008 Installation Worker ° NA NA NA NA NA Current Land -Use Total Site HI NA Future Land -Use Total Site HI 0.027 Future land -use scenario only ° Current and future land -use scenario RME - Reasonable maximum exposure ILCR = Incremental lifetime cancer risk HI - Hazard index NA - Not applicable C-7: On -Site Adult Resldenl Intake Doses and Risk for Exposure to Ground Water Scenario: Fulun Land Use Site: SWMU49 FacUllp FL Bragg, NC COPC In COPC in CCPC In COPC in Source-TernGround Water HQ hem Ground ILCR from while ILCR from vfiie HQ from COaCertrati i Noncancer 1%ostlon Carckogenic Ingestion Carckogeft Inhalation Noncancer Inhalation Sum Sum PCE._- 0.0055 1.51E-04 na 6.49E-05. 3.51E-05 1.61E-05 3.1BE-07 1.51E-05 0.00095 0.001 361E-05 TCE 0.0115 3.14E-04 na 1.35E04 1.73E-06 3.14E-05 1.89E.07 3.14E-05 1041839 0.018 1.114E-06 Chloroform 0.0011 2.88E-05 0.0004 1.29E-05 na 2 BBE oo 2.32E.07 285E-0B na 0.0004 2.32E-07 0.00059 1.82E-06 na 8.99E-08 1.39E-06 1.82E-oe 3.28E-07 1.82E-08 n2 1.71E-08 Sum of HO 0.019 Sum of ILCR 3.69E-05 7.38E-07 Total ILCR 3•M-05 Total HI 0.020 mglkg - milligram per kilogram Surface Area - 2 m' Daiv inhalation Rate - 0.4 m'/D COPC - chemical of pelenhial concern Exposure Tkne = 0.17houus/day (10 mirde shower) Voliadm1k)n Factor = 0.5 UM3 HQ ■ hazard quotient Exposuro Frequency= 350 loyal wr HI : hazard kldax E)q=um DOraW = 30 years ILCR - Incremental IBeWne caner risk Body Weight= 70 kge na - not appkAM IngssUon Rate = 2 L/day C-6: Installation WorkedGroundskeeper Intake Doses and Risk for Exposure to Ground Water Scenario: Future Land Use Site: SWMU-69 Facility: Ft. Bragg, NC Ingestion of Ingestion of COPC in COPC in Source -Term Ground Water HQ from Ground Water ILCR from Sum Sum Concentration Noncancer Ingestion Carcinogenic Ingestion HQ ILCR Chemical (mg/L) (mg/kg-day) (mg/kg-day) Organics PCE 0.0055 5.4092E-05 na 1.93E-05 1.04E-05 na 1.04E-05 TCE 0.0115 1.1230E-04 na 4.01 E-05 5.21E-07 na 5.21E-07 Chloroform 0.0011 1.0274E-05 0.0100 3.67E-06 na 0.0100 na 1,1,2,2-TeCA 0.00059 5.7730E-06 na 2.06E-06 4.12E-07 na 4.12E-07 Total ILCR 1.10E-05 Total HI 0.0000 0.0000 1.14E-05 mglkg - milligram' per kilogram COPC - chemical of potential concern HQ = hazard quotient HI =. hazard index ILCR - incremental lifetime cancer risk na - not applicable Ingestion Rate =1 Uday Exposure Frequency = 250 days/year Exposure Duration = 25 years Body Weight = 70 kgs - ' n C-9: On4ite Child Resident Intake Doses and Risk for Exposure to Ground Water Scenario: Future Land Use Site: SWMU49 Facility: Ft. Bragg, NC Dermal Contact Dermal Contact Ingestion of Ingestion of with COPC while with COPC COPC im . COPC In Source -Term bathing HQ from while Bathing ILCR from Ground Water , HQ from Ground Water ILCR from Concentration Noneancer Dermal Carcinogenic Dermal Noncancer 'Ingestion Carcinogenic Ingestion Sum Sum PCE 0.0055 TCE 0.0115 Chloroform 0.0011 1,1.2,2-TeCA 0.00059 2.97E-05 2.02E-05 1.84E-06 7.05E-07 na na 0.001 na 2.02E-05 1.09E-05 3.53E-04 2.02E-05 1.47E-06 7.34E-04 1.84E-06 na 6.71E-05 7.05E-07 2.02E-07 3.77E-05 na na 0.007 na 3.03E-05 6.29E-05 5.75E-06 3.23E-06 6.36E-07 3.77E-07 4.63E-07 6.56E-07 na na 0.008 na 1.16E-05 1.85E-06 4.83E-07 8.58E-07 Sum of HI] na 0.000 Sum of ILCR 1.24E-05 1.01E-06 Total ILCR 1.47E-05 Total HI 0.008 mg/kg - milligram per kilogram Surface Area = 0.7 mz COPC - chemical of potential concern Exposure Time = 0.17 hours/day (10 minute shower) Ha = hazard quotient Exposure Frequency = 350 days/year HI = hazard Index Exposure Duration = 6 years ILCR - incremental lifetime cancer risk Body Weight =15 kgs na - not applicable Ingestion Rate =1 Uday Remadial.Gold Options Calculation for Groundwater. (Future Land Use - OnSlte Adult Residential Swede) For Carol ns:' Calculated Risk' EPC. : Target Risk ROO Ta et Risk ROO Ta et Risk ROO MCL NC2L Tehachbroethene' 3.54E-05 "". 0.0055 " - LODE-06. 0.0002 " . 1.00E-05 :0.002 1.00E04" 0.016. .0.005." 0.0007- Trlcttbroatttene . 1.84E-O6 " " 0.011 ` 1.00E.05 ' 0.0059 1.00E-05 -0.059 1.00E-04- 0.588 .' .0.005 0.0028- CAbmforrn : 2.32E-07 0.001 1.00E-O6 " ." 0.0045 " " 1,00E-05 0.045 1.00E04 ". 0.463 0.1' . 0.07 1,1.2,2-Tatrachbroethana 1.71E-06" ".' .0.00059 1.00E-08 6.0003 1.00E-05 0.003" 1.00E-04 0.03 none" 0.00017" "KpJawo RSix 13 WSW Wf 9eGl1 MVuVin Va� ollrlYa4YO W V.w. EPC: ,Exposure Point Concentration'.' Concentration In mplL. RGO (chemical l) = EPC 0-1411)x Target RlsidCalculated R16k(chemical 1) Rrimedlal Goal Optlons.Calaulation for Groundwater (Future Land Use.- On-Slte Child Roaldendal Senerlo) For Carom" ens: CSlculated Risk' EPC Target Risk RGO Target Risk RGO T et Risk ROO MCL NC2L Tetrachlcroethene .. 1.16E-05. 0.0055 1.00E-08 - ' 0.0005 . 7.00E-.05. 0.005 '- .' -1.00E-04 0.0,5 . 0.005 0.0607 Trichbtmthene. 1.fi5E-06. 0.011, 1.00E-06 0.0062- 1.00E-05 O.062 1.00E-04 0.62 0.005 0.0028. Chl6rotonn.. 1,1,2,2-Tetracttbroetfiane 4.63E-07. i. 8.58E-07 0.001 0.00059. 1.00E-06 1:00E-06 0.0023 0.001' 1.00E-05 1:00E-05 . 0.023 - 0.01 1.00E-04 1.00E-04" 0.23 0.07 D.1 none 0.07' 0.00017 Calculated Rlsk is total tor.each chemical r all exposure routes . EPC: Exposure Point Concentration . Concentratlon in mg/L RG,O (chemical 1)'= EPC (charnteal 1) x Target MeldCalculeted Risk (Ghemloal U RemedWGoal OpGons'Catculallonfor Groimdwatar(Future Land Use- Installation Workor/GroundsKesperSonedo) ._ For Carcin sns:. Calculated Rlak'' EPC Ta st Risk ". RGO - 7 et Ris RGO Ta at Risk RGO, " . MCL tIC21 Tetrachloroethene. t:04E-05 0.0055 1.00E-0fi 0:001- 1.00E-05 0.01 . 1:00E-04. • . 0.05 0.005 - 0.0007 Trlohloroethene' 6.21E.O7.. -' 0,011 1.00E-011 _' 0.018- 1.00E-0y - 0.18'. ' .1.00E-04 - 1.84, 0.005 0.0028 1,1,2.2-Tetrachloroelhans 1.44E-07 � 0.00059 1.00E nFt 0.004 1.00E-05 0.04 - .1.00E-04 . 0A1 .' none: 0.00017 Table C-10 Remedial Goal 110 Ions for Groundwater (cont) Remedial Goal Options Calculation for Groundwater (Future Lend Use - On -Site Adult Residential Senerio) For Non-Carcln Calculated Risk EPC Target Risk RGO Target Risk RGO Target Risk RGO MCL NC2L Tetrachloroethene 0.001 0.0055 0.1 0.56 1 5.57 3 16.71 5 0.0007 Trichloroethene 0.017 0.011 0.1 0.07 1 0.66 3 1.98 5 0.0028 Chlorfona 0.0004 0.001 0.1 0263 1 2.625 3 7.88 100 0.07 EPC: Exposure Point Concentration Concentration In mg& RGO (chemical 1) = EPC (chemical 1) x Target Risk/Calculated Risk (chemical 1) Remedial Goal Options Calculation for Groundwater (Future Lend Use - On -Site Child Residential Senedo) For Non-Carcln ns: Calculated Risk EPC Target Risk RGO Target Risk RGO Target Risk RGO MCL NC21. Tetrachloroethene 0.023 0.0055 0.1 0.024 1 0.239 3 0.72 5 0.0007 Trichlomethene 0.403 0.011 0.1 0.003 1 0.028 3 0.08 5 0.0028 Chlorfonn 0.008 0.001 0.1 0.013 1 0.131 3 0.39 100 0.07 EPC: Exposure Point Concentration Concentration in mp/L RGO (chemicat 1) = EPC (chemical 1)x Target Wsk/Celculated Risk (chemical 1) Remedial Goal Options Calculation for Groundwater (Future Land Use -Installation Worker/Groundskeeper) For Non-Csrcino ns: Calcul&Wd Risk EPC Tarlist Risk RGO Target Risk RGO Target Risk RGO MCL NC2L Tetrachioroethene na 0.0055 0.1 na 1 na 3 na 5 0.0007 Trichloroethene na 0.011 0.1 na 1 na 3 na 5 0.0028 Chlorform 0.010 0.001 0.1 0.011 1 0.105 3 0.32 100 0.07 EPC: Exposure Point Concentration Concentration In mg/L RGO (chemical 1) - EPC (chemical 1) x Target Risk/Calculated Risk (chemical 1) APPENDIX C SUPPORTING PERFORMANCE DATA APPENDIX C, TABLE 1 ENHANCED BIOREMEDIATION APPLICATION PERFORMANCE DATA SWMU69 FORT BRAGG, NORTH CAROLINA Performance Pre -Installation Post -Installation Concentration .Period Maximum Maximum Reduction Application Site Substrate In'ected Primary Contaminants months Concentration n Concentration ,,iL ercent TCE 4,200 200 95 Travis Air Force Base, Site SS015 Soybean Oil cis-1,2-DCE 35 22,000 1,700 92 VC 17,000 410 98 TCE 8,400 599 93 Tinker Air Force Base, Site FTA-2 Soybean Oil and Sodium Lactate cis-1,2-DCE 23 860 2,020 NA 1,2-DCA 280 31 89 Naval Air Station Fort Worth, Site AOC-2 Soybean Oil and Sodium Lactate TCE cis-1,2-DCE 26 410 6.4 71 62 83 NA McClellan Air Force Base, Site IC-42 Soybean Oil and Sodium Lactate TCE 26 180 24 87 cis-1,2-DCE. 3 11 NA TCE 33,000 <1.0 100 Cape Canaveral Air Force Station, Hanger K Soybean Oil 1,1-DCE 70 800 <1.2 100 cis-1,2-DCE 170,000 0.99 J 100 VC 38,000 190 99.5 PCE 1,300 380 71 TCE 13 16 NA Newark Air Force Base, Site FF-87 Soybean Oil cis-1,2-DCE 63 46 320 NA 1,1,1-TCA 150 15 90 I,l-DCA 1 31 15 52 Naval Industrial Ordnance Plant Fridley, Site ACP Soybean Oil TCE 48 1,400 <1.0 100 cis-1,2-DCE 5.2 150 NA APPENDIX D CONTAMINANT OF CONCERN CONCENTRATIO�4.TRENDS -�, : . r ?� . �� .� MW9 ON sm 40 A -Al IS S-ap"94 Jain.-97 Mar-00 Dec�02 S( pp 0. Date � �� v _ �, 2� ;� ~�`��. ti . s �, f' _ — IRENE ,., ,1, -60. c c� cu 5 40 0 W 20 0 pep-94 Jun-97 .Mar--00 Dec-62 - Sep-QS Tire -SCE 0 W 2® pep-94 Jain-97. i\/ar�00 D�c-92. Time Sep ®5 e=.TCE. P.0 E �_ oo� �o - +- 69.MW21 D o® .�, 1 � 69 MW22D 40