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Home My WebLink AboutCenco_Annual GW Monitoring 2007 ANNUAL GROUNDWATER MONITORING REPORT (2007) HONBARRIER, INC. FACILITY CHARLOTTE, MECKLENBURG COUNTY, NORTH CAROLINA GROUNDWATER INCIDENT NO.: 8440 DELTA PROJECT NO.: 5E0711711P 1.0 INTRODUCTION Delta Consultants (Delta), on behalf of Honbarrier, Inc. (Honbarrier), has prepared this Annual Groundwater Monitoring Report in accordance with the North Carolina Department of Environment and Natural Resources (NCDENR), Division of Water Quality, Groundwater Section correspondence dated May 7, 2002, and titled, Modification of Sampling Plan (MSP). As per the revised sampling plan, monitoring wells MW-2, MW-13, and MW-19 will be sampled on an annual basis and the groundwater samples will be analyzed for volatile organic compounds (VOCs) according to EPA Method 601. In addition, monitoring well MW-7 will be sampled on an annual basis and the groundwater sample will be analyzed for VOCs according to EPA Methods 601 and 602. This annual monitoring report summarizes the monitoring event conducted in December 2007. The location of the subject site is presented in Figure 1.1. 2.0 ACTIVITIES PERFORMED DURING THIS PERIOD The following tasks were completed during the reporting period: • Depth to groundwater was gauged at monitoring wells MW-2, MW-7, MW- 13, and MW-19 on December 27, 2007; • Groundwater samples were collected from monitoring wells MW-2, MW-7, MW-13, and MW-19 on December 27, 2007; and, • Field measurements including dissolved oxygen (DO), pH, specific conductivity, oxidation reduction potential (ORP), and temperature were collected from monitoring wells MW-2, MW-7, MW-13, and MW-19 on December 27, 2007. Annual Groundwater Monitoring Report (2007) Honbarrier, Inc. Charlotte, North Carolina Groundwater Incident No.: 8440 Delta Project No.: 5E0711711P 2 3.0 SITE HISTORY Honbarrier provided bulk-hauling services to a variety of industries. The entire site consists of 30 acres, approximately six acres of which were actively used for terminal operations. The terminal operations began in 1969, under the name Central Transport Incorporated. The site had been farmed prior to its purchase. The facility consisted of a terminal office, maintenance garage, truck wash bays, a boiler house for steam production, a wastewater pretreatment system, former waste treatment lagoons, and parking facilities for empty tank trucks. The site included a facility for cleaning the inside of empty tank trucks following delivery of bulk chemicals. Rinse waters generated from these washing operations were collected and treated prior to discharge to the Charlotte Mecklenburg Utility District treatment plant in accordance with permit number 0188. Historically, two on-site impoundments were used to treat tank truck rinse waters. During the 1970s and 1980s, site operations resulted in the release of contaminants into the soil and groundwater. Use of the impoundments was terminated in 1985 when a new pretreatment system commenced operation. Closure of the impoundments began in 1991. The impoundments closed as a landfill in 1992 and are capped to meet Resource Conservation and Recovery Act requirements. Drawing 3.1 shows the location of site surface features, the regulated unit (closed landfill), and seven site monitoring wells installed during the contamination assessment process. Monitoring wells MW-9, MW-10, MW-11, MW-12, MW-14, MW-15, and MW-17 were abandoned on May 15, 1999 (following approval by the NCDENR) and are no longer represented on the site map. Terminal operations at the site ceased in approximately 1995 and the property was vacated. The subject site is currently leased and utilized as a truck storage terminal. Annual Groundwater Monitoring Report (2007) Honbarrier, Inc. Charlotte, North Carolina Groundwater Incident No.: 8440 Delta Project No.: 5E0711711P 3 4.0 FIELD ACTIVITIES Delta mobilized to the site on December 27, 2007, to conduct the groundwater sampling activities. The four monitoring wells sampled during the annual event included MW-2, MW-7, MW-13, and MW-19 (Drawing 3.1). Monitoring well MW-6 has been destroyed by apparent mowing activities. Prior to purging the wells of at least three volumes of water (or to dryness) using new disposable bailers, Delta measured the depth to water in each well to be sampled using a decontaminated electric water level indicator. A new pair of protective, non-reactive gloves was donned at each well prior to collecting water level measurements. The measured depths were subtracted from the casing elevations to determine the groundwater elevation relative to Mean Sea Level. The physical characteristics of the site monitoring wells and groundwater elevation data are summarized in Table 4.1. After purging the wells, water samples were collected from the same bailers used to purge each well and decanted into laboratory-supplied containers. The containers were placed into an ice-filled cooler and transported under chain-of-custody to Pace Analytical Services, Inc. (PACE) of Huntersville, North Carolina. At the laboratory, the four groundwater samples were analyzed for VOCs according to EPA Method 601. The groundwater sample collected from monitoring well MW-7 was also analyzed for VOCs according to EPA Method 602. In addition, groundwater field measurements were collected for DO, pH, electrical conductivity, ORP, and temperature (Table 4.2). 5.0 GROUNDWATER FLOW Groundwater flow direction in the surficial aquifer was estimated based on water level data obtained from the monitoring wells on December 27, 2007 (Drawing 5.1). Annual Groundwater Monitoring Report (2007) Honbarrier, Inc. Charlotte, North Carolina Groundwater Incident No.: 8440 Delta Project No.: 5E0711711P 4 Interpretation of the relative water table elevations suggests that groundwater flows generally to the south across the site. This flow direction is consistent with previously interpreted flow directions. On average, static water levels measured in the four monitoring wells have decreased 2.4 feet since December 2006. 6.0 ANALYTICAL RESULTS The laboratory analytical results for the groundwater samples collected on December 9, 2005, are contained in Appendix A and summarized in Table 6.1. The groundwater sample collected from monitoring well MW-2 exhibited the presence of vinyl chloride at a concentration of 1.8 micrograms per liter (µg/L), which exceeded its established North Carolina Groundwater Quality Standard (NCGQS). Two additional VOCs were detected in the groundwater sample collected from MW-2 in concentrations below their respective NCGQS. As summarized, benzene, chlorobenzene, 1,4-dichlorobenzene, and vinyl chloride were detected in the groundwater sample collected from MW-7 at concentrations of 134 µg/L, 518 µg/L, 33.5 µg/L, and 11.3 µg/L, respectively, which exceeded their established NCGQS. Three additional VOCs were detected in the groundwater sample collected from MW-7 in concentrations below their respective NCGQS. Vinyl chloride (32.2 µg/L) and cis-1,2-dichloroethene (223 µg/L) were detected in the groundwater sample collected from monitoring well MW-13 in concentrations which exceeded their respective NCGQS. Two additional VOCs were detected in the groundwater sample collected from MW-13 in concentrations below their respective NCGQS. Annual Groundwater Monitoring Report (2007) Honbarrier, Inc. Charlotte, North Carolina Groundwater Incident No.: 8440 Delta Project No.: 5E0711711P 5 No VOCs were detected in the groundwater sample collected from monitoring well MW-19 in concentrations which exceeded established NCGQS. Two VOCs were detected in the groundwater sample collected from MW-19 in concentrations below their respective NCGQS. A total VOC concentration map, showing total detectable VOCs, is provided as Drawing 6.1. Historical groundwater sample results and a site map showing existing and previously abandoned monitoring wells are presented in Appendix B. 7.0 SUMMARY AND CONCLUSIONS Based on the field and laboratory analytical results, Delta offers the following summary and conclusions. • Shallow groundwater flow is directed toward the south across the site. • The groundwater sample collected from monitoring well MW-2 exhibited a concentration of vinyl chloride, which exceeded its established NCGQS. Concentrations of total VOCs detected in the groundwater sample collected from MW-2 continue to decrease and are currently at a historical low. • The groundwater sample collected from monitoring well MW-7 exhibited the presence of benzene, chlorobenzene, 1,4-dichlorobenzene, and vinyl chloride in concentrations which exceeded their NCGQS. Concentrations of dissolved petroleum-related VOCs have increased since the last sampling event conducted in December 2006. Historically, concentrations of total VOCs detected in the groundwater samples collected from MW-7 exhibit non-static conditions. • Vinyl chloride and cis-1,2-dichloroethene were detected in the groundwater sample collected from monitoring well MW-13 in concentrations which Annual Groundwater Monitoring Report (2007) Honbarrier, Inc. Charlotte, North Carolina Groundwater Incident No.: 8440 Delta Project No.: 5E0711711P 6 exceeded their respective NCGQS. Concentrations of total VOCs detected in the groundwater sample collected from MW-13 have decreased since December 2006. • No VOCs were detected in the groundwater sample collected from monitoring well MW-19 in concentrations above established NCGQS. Concentrations of total VOCs detected in the groundwater sample collected from MW-19 continue to decrease and are currently at a historical low. Total dissolved VOCs detected in the groundwater samples collected from the four monitoring wells in December 2007 have increased since the sampling event conducted in December 2006. This increase is due predominantly to an increase in petroleum-related VOCs detected in the water sample collected from MW-7. Based on the information presented in this report and past groundwater analytical data, Delta concludes that the chlorinated VOC groundwater contaminant plume identified at the subject site exhibits characteristics indicative of biodegradation and physical attenuation. No parent compounds (trichloroethene, tetrachloroethene) were detected at concentrations at or above the laboratory reporting limits in the groundwater samples collected from the four monitoring wells sampled in December 2007. In addition, no VOCs were detected in the groundwater sample collected from the off-site, down gradient well MW-19 at concentrations above established NCGQS. The remaining chlorinated daughter compounds (1,1-dichloroethene, vinyl chloride) detected in the groundwater samples are likely the result of degradation of the parent compound(s). The next groundwater sampling event should be conducted in December 2008. If no VOCs are detected in the groundwater sample collected from MW-19 at concentrations above Annual Groundwater Monitoring Report (2007) Honbarrier, Inc. Charlotte, North Carolina Groundwater Incident No.: 8440 Delta Project No.: 5E0711711P 7 established NCGQS during the 2008 sampling event, Delta will recommend the proper abandonment of MW-19. This report was prepared by: DELTA CONSULTANTS _____________________________________ John D. Reuscher, P.G. Project Manager TABLES FIGURES APPENDICES APPENDIX A LABORATORY ANALYTICAL REPORT AND CHAIN-OF- CUSTODY RECORD APPENDIX B HISTORICAL GROUNDWATER SAMPLE RESULTS TABLE OF CONTENTS 1.0 INTRODUCTION ................................................................................... 1 2.0 ACTIVITIES PERFORMED DURING THIS PERIOD .............................. 1 3.0 SITE HISTORY ..................................................................................... 2 4.0 FIELD ACTIVITIES ............................................................................... 3 5.0 GROUNDWATER FLOW ...................................................................... 3 6.0 ANALYTICAL RESULTS ....................................................................... 4 7.0 SUMMARY AND CONCLUSIONS ......................................................... 5 FIGURES Figure 1.1: Topographic Location Map Figure 3.1: Site Map Figure 5.1: Estimated Shallow Groundwater Flow Map Figure 6.1: Total VOC Concentration Map TABLES Table 4.1: Physical Characteristics of Existing Monitoring Wells Table 4.2: Summary of Groundwater Field Parameters Table 6.1: Summary of Chemical Constituents Detected in Groundwater APPENDICES Appendix A: Laboratory Analytical Report and Chain-of Custody Record Appendix B: Historical Groundwater Sample Results ANNUAL GROUNDWATER MONITORING REPORT (2007) HONBARRIER, INC. FACILITY CHARLOTTE, MECKLENBURG COUNTY, NORTH CAROLINA GROUNDWATER INCIDENT NO.: 8440 DELTA PROJECT NO. : 5E0711711P This report was prepared for: Honbarrier, Inc. P.O. Box 7027 High Point, North Carolina 27263 This report was prepared by: Delta Consultants 8008 Corporate Center Drive, Suite 100 Charlotte, North Carolina 28226 (704) 543-3928 January 2008