WQ0036881_(Investigation)_20130628

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28 June 2013
Mr. John Johnston
U.S. Environmental Protection Agency
Atlanta Federal Center
61 Forsyth Street, SW
Atlanta. GA 30303-8960
Re: RCRA Facility Investigation Report
Former Clifton Precision Site, Murphy, North Carolina
EPA ID No. NCD 044 438 406
Dear Mr. Johnston:
Northrop Grumman Corporation
2980 Fairview Park ❑rjve
Fails Church, Virginia 22042-4511
Joseph P. Kwan
703-28"035
Joe [e-mail]
Northrop Grumman Guidance and Electronics Company, Inc. is submitting the document
referenced above for your review and approval. This document has been revised to include
the latest investigation data for the site and supersedes the RCRA Facility Investigation
Report submitted in July 2010.
If you have any questions regarding this submittal, {Tease contact me at [phone] or
Kurt Batsel. our project manager, at [phone].
Sincerely,
Joseph P. Kwan
Corporate Director. Environmental Remediation
on behalf of Northrop Grumman Guidance and Electronics Company, Inc.
Enclosure: RCRA Facility Investigation Report (June 2013)
cc: Rob McDaniel - NCDENR
Kurt Batsel - Dextra
Merl Scappatura - Moog
Andrew Romanek - CDM Smith

RCRA Facility Investigation Report
Former Clifton Precision Site
1995 N Carolina 141
Murphy, NC 28906
Prepared ❑n behalf of:
Northrop Grumman Guidance and Electronics Company, Inc.
2980 Fairview Park Drive
Falls Church, VA 22042
June 2013
Smith

Table of Contents
Contents
Executive Summary
Section 1 Introduction
LASite History .................................................................. .............................................................. 1-1
1.2
Waste Management Unit Descriptions.............................................................................. 1-1
1.2.1
WMU-A: Drum Storage Area ...................................... ............
.............................. 1-1
1.2.2
WMU-B: Underground Storage Tank ..................... .........................
................. 1-2
1.2.3
WMU-C: Underground Crushed Tanks............................................................1-3
1.2.4
WMU-D: Drainfield..................................................................................................1-3
1.2.5
WMU-E: Treatment Area and Filtration Pit ........ ............................
........ ....... 1-3
1.2.6
WMU-F: Chemical Treatment Building ........... ...........
................... .................. 1-4
1.2.7
WMU-G: Percolation Pit.........................................................................................1-4
1.2.8
WMU-H: Polishing Pond........................................................................................1-5
1.3
Previous Groundwater Actions ....... ...................... ..................... ........................
................... 1-5
1.4
Project Objectives ......................... ........ ........................ ................ ...........
..... .......... ......... I ....... ... 1-7
t.5
Project Scope................................................................................................................................1-8
1.5.1
Phase 1..........................................................................................................................1-8
1.5.2
Phase 2................................................... ................................................
............... ....... 1-9
1.5.3
Phase 3........................... ........ ...................................................................................
-1-18
1.5.4
Additional Investigation Activities ............... ...................................................
1-10
Section 2 Environmental Setting
2.1 Land Use......................................................................................................................................... 2-1
2.2 Topography and Drainage ...................................................................................................... 2-1
2.3 Regional Geology........................................................................................................................ 2-1
2.4Hydrogeology...............................................................................................................................2-2
Section 3 Procedures
3.1
Subsurface Investigations.......................................................................................................
3-1
3.1.1 Regolith Well InstalIation.....................................................................................
3-1
3.1.2 Exploratory Borings................................................................................................
3-2
3.1.3 Bedrock Well Installation.....................................................................................
3-3
3.1.4 Rock Coring................................................................................................................
3-3
3.1.5 Onsite Source Screening........................................................................................
3-4
3.1.6 Soil Borings.................................................................................................................
3-4
3.1.7 Geophysical Logging...............................................................................................
3-4
3.1.8 Geophysical Survey..................................................................................................
3-4
3.2
Groundwater Sampling............................................................................................................
3-6
3.3
Water -Use Survey and Water Supply Samp]ing.............................................................
3-6
3.4
Surface Water Sampling...........................................................................................................
3-7
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Sinith RCRA Facility Investigation Report

Table of Contents
3.5 Soil Sampling................................................................................................................................ 3-7
3.6 A uiFer Performance Testin................................ .................... ................ ............................. 3-8
3.7 Investigation Derived Waste.................................................................................................. 3-8
Section 4 Results
4-1
42
4.3
4.4
4.5
4.6
4.7
4.8
4.9
4.10
Section 5
Phase1............................................................................................................................................ 4-1
4.1.1 Regolith Groundwater Screening Investigation ..........................................
4-1
4.1.2 Regolith Groundwater Investigation................................................................
4-1
4,1.3 Bedrock Groundwater Investigation ................................................................
4-1
Phase2............................................................................................................................................
4-2
4.2.1 Regolith Groundwater Investigation................................................................
4-2
4.2.2 Bedrock GroundwaterInvestigation................................................................
4-2
Water -Use Survey and Water Supply Sampling.............................................................
4-2
4.3.1 Water -Use Survey ........... ........................... ........................................ ......... .............
4-2
4.3.2 Water Supply Sampling.......................................................................................
4-2
Phase3............................................................................................................................................
4-3
4.4.1 Regolith Groundwater Investigation................................................................
4-3
4.4.2 Bedrock Groundwater Investigatian................................................................
4-3
4.4.3 Surface Water Sampling........................................................................................
4-3
❑nsite Source ScreeningInvestigation..............................................................................4-4
Additional Soil Assessment....................................................................................................4-5
West Groundwater Flow Evaluation..................................................................................
4-5
WMU-B Investigation.............................................................................................................4-11
OFfsite Groundwater Investigation ....................................................................................4-12
Quality Assurance/Quality Control Samples.................................................................4-15
4.10.1 Laboratory Analyses.............................................................................................4-15
4.10.2 Field Samples ...... ..................................................................... ............ ........ ........ ....4-16
Conclusions
5.1 Geology ................................. ........................................................................................................... 5-1
5.1.1 Regolith Zone Geology............................................................................................
5-1
5.1.2 Transition Zone Geology.......................................................................................
5-2
5.1.3 Bedrock Zone Geology...............................................:............................I...............
5-2
5.2
Hydrogeology...............................................................................................................................5-3
5.11 Regolith and Transition Zone Hydrogeology................................................
5-3
5.2.2 Bedrock Zone Hydrogeology................................................................ ..
5-4
5.3
VOCs in Groundwater...............................................................................................................
5-4
5.4
VOCs in Surface Water..............................................................................................................
5-5
5.5
VOCs in Soil...................................................................................................................................
5-6
5.6
Conceptual Hydrogeologic Model........................................................................................
5-6
5.6.1 VOC Source..................................................................................................................
5-6
5.6.2 Onsite VOC Migration in Groundwater............................................................
5-6
5.6.3 ❑ffsite VOC Migration in Groundwater...........................................................
5-7
CDM
5riiith RCRA Facility Investigation Report

Fable of Contents
Section 6
Section 7
Summary
References
Appendices (an CD-ROM)
A Boeing Logs and Well Construction Diagrams
H Membrane Interface Probe Screening Plots
C Geophysical Logs
D Geophysical Survey Transect Data
E ❑ffsite Groundwater Investigation - Aquifer Perform
F Laboratory Reports
G Soil Sample Physical Testing Results
Figures
1-1 Site Location Map
1-2 Waste Management Unit Location Map
1-3 RFI Phases 1 — 3 Investigation Location Map
1-4 Qnsite Source Screening Investigation Locations
L-5 Additional Soil Assessment Boring Locations
1-6 Additional Soil Assessment Background Locations
1-7 West Groundwater Flow Evaluation Locations
1-8 WMU-B Investigation locations
1-9 Offsite Groundwater Investigation Locations
1-10 Geophysical Survey Transect Locations
2-1 Land Use Map
2-2 Topographic Map
2-3 Regional Geologic Map
4-1 Regolith Screening Locations
4-2 Water -Use Survey & Supply Sample Locations
4-3 MIP Cross -Section Locations
4-4 Electron Capture Detector Cross -Section A -A'
4-5 Photoionization Detector Cross -Section A -A'
4-6 Flame Ionization Detector Crass -Section A -A'
4-7 Electron Capture Detector Cross -Section B-B'
4-8 Photoionization Detector Cross -Section B-B'
4-9 Flame Ionization Detector Cross -Section B-B'
4-10 Regolith Potentiometric Surface Map
4-11 Bedrock Potentiometric Surface Map
4-12 PW-16 Aquifer Performance Test Hydrograph
4-13 PW-22A Aquifer Performance Test Hydrograph
4-14 PW-23 Aquifer Performance Test Hydrograph
4-15 PW-39 Aquifer Performance Test Hydrograph
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Smith RC RA Facility Investigation Report

Fable of Contents
4-16
4-17
4-18
4-19
4-20
4-21
4-22
4-23
4-24
4-25
4-2 6
4-27
4-28
4-29
4-3 0
4-31
4-3 2
4-33
4-34
5-1
5-2
5-3
5-4
5-5
5-6
5-7
5-8
5-9
5-10
Tables
1-4
1-2
1-3
2-1
3-1
4-1
4-2
4-3
4-4
4-5
Acoustic Televiewer Fracture Plots
VOC Time Trends
WMU-B Cross -Section Locations
WMU-B Geologic Cross -Section A -A'
WMU-B Geologic Cross -Section B -B'
WMU-B Geologic Cross -Section C-C'
WMU-B Shallow Soil TCE Isoconcentration Contou
WMU-B Shallow Soil PCE Isoconcentration Contou
WMU-B Deep Soil TCE Isoconcentration Contours
WMU-B Deep Soil PCE Isoconcentration Contours
WMU-B Shallow Groundwater TCE Isoconcentration trontraurs
WMU-B Shallow Groundwater PCE Isoconcentration Contours
WMU-B Deep Groundwater TCE Isoconcentration Contours
WMU-B Deep Groundwater PCE Isoconcentration Contours
WMU-B Bedrock Groundwater TCE Concentrations
WMU-B Bedrock Groundwater PCE Concentrations
WMU-B Regolith Groundwater Potentiometric Surface Map
WMU-B Bedrock Groundwater Potentiometric Surface Map
Geophysical Survey Conclusions
Transition Zone Surface Elevation Map
Transition Zone Thickness Map
WMU-B Area — Transition Zone Surface Elevation Map
Bedrock Zone Surface Elevation Map
Regolith/Transition Zone Potentiometric Surface Map
Bedrock Zone Potentiometric Surface Map
Regolith/Transition Zone Total VOCs
Bedrock Zone Total VOCs
Surface Water Data Summary
Total VOCs in Soil by Depth at WMU-B
Site History
Scope of Work for RFI Phases 1 through 3
Scope of Work for Additional Investigations
Regional Geologic Formations
Monitoring Well Construction Summary
Groundwater Screening Data
Groundwater Screening Laboratory Data
RFI Phase 1 Groundwater Data Summary
RFI Phase 2 Groundwater Data Summary
Water Supply Data Summary
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Smith RC RA Facility Investigation Report

Fable of Contents
4-6 RFI Phase 3 Groundwater Data Summary
4-7 Surface Water Data Summary
4-8 Membrane Interface Probe Screening Results Summary
4-9 Onsite Source Screening - Soil Sampling Summary
4-10 Onsite Source Screening - SoiI Sampling Results
4-11 Additional Sail Assessment VOC Results
4-12 Additional Soil Assessment Metals Results
4-13 West Groundwater Flow Evaluation - Measured Water Levels
4-14 West Groundwater Flow Evaluation - Well Construction Summary
4-15 West Groundwater Flow Evaluation - APT Summary
4-16 Geophysical Logging Results
4-17 West Groundwater Flow Evaluation - Vertical Profiling Data
4-18 Site Boundary Well Data Statistics
4-19 West Groundwater Flow Evaluation - Historical Supply WeII Data
4-20 WMU-B Soil Data Summary
4-21 WMU-B Soil Borings - Groundwater Data Summary
4-22 WMU-B -VOC and Metals Results for New Monitoring Wells
4-23 WMU-B - General Chemistry Summary of New Monitoring Wells
4-24 WMU-B -- Water Quality Measurements For New Monitoring Wells
4-25 Reinjection Well Aquifer Test Results
4-26 Offsite Groundwater Investigation - Laboratory Data Summary
4-27 Groundwater- and Surface Water Field Duplicate Results
4-28 Soil Field Duplicate Results
5-1 VOC Statistics for Onsite Groundwater Data
5-2 VOC Statistics for Offsite Groundwater Data
CDM
Smith RCRA Facility Investigation Report V

Table of Contents
Abbreviations and Acronyms
APT
aquifer performance test
ASTM
American Society For Testing and Materials
bgs
below ground surface
CDM
Camp Dresser & McKee Inc.
CDM Smith
CDM Smith Inc.
CMS
Corrective Measure Study
DCA
dichloroethane
DCE
dichloroethene
DPT
direct -push technology
ECD
electron capture detector
EPA
U.S. Environmental Protection Agency
FID
flame ionization detector
gpm
gallons per minute
ID
inside diameter
IM
interim measure
MCL
federal Maximum Contaminant Level
mg/kg
milligrams per kilogram
MEK
methyl ethyl ketone (2-butanone)
M I P
membrane interface probe
MTBE
methyl tent -butyl ether
mV
millivolts
NGVD
National Geodic Vertical Datum 1929
ODEX
eccentric air -hammer bit
Order
Administrative Order on Consent
PCE
tetrachloroethene
PI❑
photoionization detector
POTW
publicly owned treatment works
PVC
polyvinyl chloride
QA/QC quality assurance quality control
RC RA
Resource Conservation and Recovery Act
RFI
RCRA Facility Investigation
RSL
Regional Screening bevel
SCS
Stearns, Conrad, and Schmidt Consulting Engineers, Inc.
SVE
soil vapor extraction
TCA
trichloroethane
TCE
trichloroethene
µg/kg
micrograms per kilogram
µg/L
micrograms per liter
LIST
underground storage tank
VER
vacuum enhanced recovery
VLF
very low frequency
VOCs
volatile organic compounds
WMU
waste management unit
CDM
Smith RCRA Facility Investigation Report V1

Executive Summary
Executive Summary
This RCRA Facility Investigation Report (RFI) describes the extent afvoIatile organic compounds
(VOCs) in groundwater, surface water, and soil at the former Clifton Precision site located near
Murphy, North Carolina. Multiple phases of assessment were performed between August 2005
and November 2012 to define the nature and extent of VOCs. The results of each of these
assessments are presented in the report along with an updated site conceptual model.
Operations at the Facility began in 1967 with the manufacture of small electric rotary parts and
electric motors. in 1998, the facility entered into an Administrative Order on Consent (Order)
with the U.S. Environmental Protection Agency. The Order identified eight solid waste
management units (WMUs). Several investigation and remediation activities were conducted
From 1986 through 2003, including excavation of an underground storage tank (WMU-B), two
phases of an RFI, and installation of groundwater extraction and soil vapor recovery systems.
These activities are briefly summarized in this report and documented in previous reports. This
report supersedes previous assessment and characterization conclusions.
Land use in the site vicinity is primarily rural residential. The site is bounded to the north by Slow
Creels with rural residential properties located to the north and the west. To the south, the site is
bounded by commercial and industrial Iand uses, including a service station, hardware store, and
manufacturing facility. The site is located on the border of a stream valley that drains to the
south-southwest into the Hiawassee River. Surface topography and drainage on site is primarily
to the north toward Slow Creek.
The site is also located in the Blue Ridge Physiographic Province (Blue Ridge), which consists
predominantly of metamorphic rock of sedimentary origin. The subsurface investigations indicate
a single aquifer that consists of three interconnected hydrogeologic zones: regolith, transition,
and bedrock. The regolith is the shallowest zone and is Composed of saprolite and alluvium. The
transition zone is present in most locations on and off site and typically consists of fractured,
partially weathered rock. The bedrock zone is interpreted to consist of the Murphy Marble at all
investigation locations. Fractures are present in both the transition and bedrock zones but occur
at a higher frequency in the transition zone. The predominant direction of groundwater flow is to
the north / northwest.
As part of the current RFI, 54 monitoring wells were installed and more than 150 soil borings
were completed. Other activities included surface water sampling, private well surveys and
sampling, geophysical logging, geophysical surveys, membrane interface probe screening, and
aquifer performance testing. Between January 2008 and November 2012 alone, which was
selected for an evaluation of current conditions, more than 420 groundwater and 690 soil
samples were collected and analyzed.
In general, VOCs were not found in soil at the WMUs at levels indicative of an ongoing source of
VOCs in groundwater with the exception of WMU-B (former underground storage tank) and, to a
much lesser extent, WMU-A (former drum storage area). For groundwater, the highest
concentration of total VOCs is on site near WMU-B, and the estimated extent of total VOCs
stretches to the north and northwest from this WMU. The most frequently detected VOCs and
CDM
Smith RC RA Facility Investigation Report £5-1

Executive Summary
those typically detected at the highest concentrations are 1,1,1-trichloroethane, 1,1-
dichloroethene, tetrachloroethene, and trichloroethene (TCE).
VOCs in regolith groundwater migrate laterally to the west through the regolith and also migrate
downward and enter bedrock groundwater in the area of WMU-B. Downgradient of WMU-B
toward the west site boundary, the transition zone becomes thicker and plays a more significant
role in VOC migration because the transition zone has a higher transmissivity that allows
groundwater to migrate more rapidly. VOCs are also present in groundwater along the north site
boundary toward Slow Creek where the transition zone is not well developed and a Bedrock ridge
exists.
Prior to the operation of the current groundwater recovery system, the VOCs in regolith
groundwater on site flawed off site toward Slow Creek and migrated into the alluvium of the
alluvial valley. VOC migration in the alluvial valley primarily occurs through the coarse -grained
alluvium and the transition zone. The offsite coarse -grained alluvium and transition zone are
much more transmissive than the ansite hydrogeoIogic zones, and the corresponding flux of
groundwater is much higher off site than on site. As a result, the VOCs in offsite groundwater are
much lower in concentration than would be expected.
VOCs in ❑ffsite bedrock have similar migration and fate characteristics. The VOCs in bedrock
groundwater migrate Iaterally on site. Off site, VOC migration is dictated by a bedrock trough, the
alluvium, and inclined rock ledges interlayered with alluvium Filled fractures. VOCs in the
alluvium ultimately discharge to Slow Creek. TCE concentrations at the two surface water stations
with the most historical detections are typically less than 10 µg/L based on semi-annual sampling
performed far the last several years.
As part of the next phase of work for this site, a Corrective Measures Study will be performed to
identify what remedy or remedies will be required to achieve protection of human health goals.
However, several Interim Measures (IMs) are already under way or planned for implementation
within the next year. IMs already in place include connection of residents potentially
downgradient From the site to the Town of Murphy water system, groundwater treatment
extraction and treatment, and soil vapor extraction. I M s planned for near -term implementation
include thermal remediation of groundwater near WMU-B and groundwater reinjection off site
with enhanced recovery on site.
CDM E5-2
Smith RC RA Facility Investigation Report

Introduction
Section 1
Introduction
The Former Clifton Precision Site (the site) is located at 1995 NC Highway 141, approximately 5
miles east of Murphy, North Carolina. Figure 1-1 shows the site location. Environmental
investigations and remediation have been performed at this site under the Resource Conservation
and Recovery Act (RCRA). This RCRA Facility Investigation (RFI) report describes the extent and
migration characteristics of volatile organic compounds (VOCs) in groundwater, surface water,
and soil characterized during onsite and offsite investigations performed between August 2005
and November 2012. These investigations were performed on behalf of Northrop Guidance and
Electronics Company, Inc.
Site -related VOCs are primarily chlorinated ethene and ethane compounds. These compounds
have been the subject of several regulatory -driven activities that include completion of this RFI,
operation of an onsite groundwater recovery system, implementation of interim measures (IMs),
and routine groundwater and surface water monitoring.
Additional background information for this site is provided in this section, which also presents
the RFI project objectives and a chronology of the RFI implementation. Section 2 describes the
environmental setting for the site and surrounding vicinity. The investigation procedures used
during the RFI implementation are described in Section 3. Section 4 summarizes the RFI results.
Conclusions and recommendations are provided in Section 5 and Section 6, respectively.
References are listed in Section 7.
1.1 Site History
Table 1-1 provides a summary of pertinent events and response actions leading up to the
submittal of this RFI report. Operations at the facility began in 1967 with the manufacture of
small electric rotary parts and electric motors. In 1980, the facility notified the U.S. Environmental
Protection Agency (EPA) of its hazardous waste activities pursuant to Section 3010 of RCRA.
VOCs were discovered in groundwater from a water supply well at the facility during tank closure
activities in 1986. In 1988, the facility entered into a Section 3008(h) Administrative Order on
Consent (Order) with the EPA (EPA Identification Number NCD 044 438 406). The Order
identified eight solid waste management units, which are shown in Figure 1-2. Detailed
descriptions of the waste management units (WMUs) are presented in Section 1.2. The Order
required an RFI, along with IMs, to mitigate the VOCs and reduce VOC migration in groundwater.
Beyond these actions, the Order required a Corrective Measure Study (CMS).
1.2 Waste Management Unit Descriptions
1.2.1 WMU-A: Drum Storage Area
WMU-A is located west of the machine shop. Drummed hazardous wastes were stored on a
concrete pad in this area from an unknown date until 1986. After 1986, this area was used to
store new chemical products in drums. According to the Phase I RFI Report prepared by Stearns,
CDM 1-1
Smith RCRA Facility Investigation Report

Introduction
Conrad, and Schmidt Consulting Engineers, Inc. (SCS), October 1990), wastes stored at WMU-A
included waste codes F001 and F003.
Soil sampling at WMU-A was performed as part of the 1990 Phase I RFI. These soil samples were
collected at seven locations along the border of the concrete pad from land surface to a depth of
0.2 Foot below land surface. Total VOCs were detected in soil at all seven Iocations at
concentrations ranging from 16 to 3,246 micrograms per kilogram (µg/kg). TetrachIoroethene
(PCE) was the most consistently detected VOC and was reported at concentrations up to 2,400
µg/kg. TrichIoroethene (TCE) was detected in only one sample at 11 µg/kg.
1.2.2 WMU-B: Underground Storage Tank
WMU-B is located adjacent to the north wall of the main plant. WMU-B formerly included a
concrete underground storage tank (UST). The 5,400-gallon UST was approximately 15 feet long,
10 feet wide and 5 feet deep. The top of the tank was approximately 1.5 feet below land surface.
The tank was baffled and received rinse water and spent chromic acid solutions from an
anodizing operation. The solutions were neutralized in the UST with sodium bicarbonate and the
effluent conveyed by gravity into a drain field consisting of twelve nitrification lines (WMU-D
discussed below).
The UST was put into operation as a wastewater treatment system in 1967 and ceased operation
in 1974. The LIST was drained in 1986 and the removed material was disposed of at all offsite
disposal facility. Later in 1986, the UST was found to contain about 900 gallons of water that had
infiltrated into the UST and this material was removed for offsite disposal. In 1987, the UST was
pumped out again and the UST was removed along with approximately 400 cubic yards of soil. A
hole was reportedly observed in the side of the concrete UST. These materials (soil and concrete)
were disposed of at an offsite disposal facility. The excavated area measured approximately 30 by
30 feet to a depth of 12 feet. Sheet piles were required to stabilize the main plant building
adjacent to the excavation, which imposed some limitations on the excavation depth and extent of
soil removal to the south.
Soil samples were collected from five locations from the excavation bottom. PCE and 1,1,1-
trichloroethane (TCA) were the most consistently detected VOCs from these soil samples. These
soil samples were also analyzed for 23 metals. Antimony, chromium, co bait, copper, magnesium,
and mercury concentrations were reported to be above the "range of concentrations in natural
soil."
In December 1988, a soil vapor extraction (SVE) system was installed around the previous WMU-
B excavation area that consisted of five vapor extraction wells that were screened from 13.5 to
19.5 feet below land surface. The SVE system was installed in response to the VOC concentrations
that were measured in the soil samples collected from the UST removal excavation. Eight SVE air
intake wells were also installed around the previously excavated area. Soil samples were
collected during the installation of the SVE extraction wells. These samples were collected at 2-
foot intervals beginning at a depth of 11 feet below land surface to 21 feet below land surface.
Total VOC concentrations from these soil samples were reported to be as high as 216,900 jig/kg,
with PCE being present at the highest concentrations, up to 170,000 µg/kg.
CS -PM RC RA Facility Investigation Report 1-�

Introduction
A vacuum enhanced recovery (VER) system, including two groundwater recovery wells (RW-1S
and RW-1❑), was installed at WMU-B in August 1996. Samples from RW-1S and. RW-1D have
routinely contained elevated VOC concentrations. Since March 1997, TCE concentrations in
samples from RW-1S have ranged from 70,000 to 130,000 µg/L.
1.2.3 WMU-C: Underground Crushed Tanks
WMU-C is located north of the machine shop building and was used for neutralizing and treating
wastewater From anodizing, pass ivating, nickel plating, zinc phosphating, and water rinsing. Only
trace amounts of chlorinated solvents reportedly entered this treatment system, which was in
operation from 1974 until 1980.
The WMU-C treatment system consisted of three 1,000-gallon USTs constructed of concrete and
coated with epoxy paint. The treatment consisted of pH adjustment in the first tank, clarification
and adjustment in the second tank, and precipitation in the third tanit. Effluent from WMU-C was
discharged to WMU-D [Drain Field].
I 1980, the tanks were emptied, crushed, and left in place. In 1987, 17 soil samples were
collected from this area at 7 locations south of the unit. The soil samples were collected at depths
ranging from 1 foot below land surface to 7 feet below land surface, VOCs were detected in all but
one sample. One sample exceeded 1,000 µg/kg total VOCs and most samples exceeded 100 µg/kg
total VOCs. The most frequently detected compounds in soil were chloroform, PCE, and TCE.
1.2.4 WMU-D: ❑rainfield
WMU-D is located north of the machine shop building and in the west portion of the onsite
baseball Field. This drain field received treated effluent from WMU-B from 1967 to 1974, treated
effluent From WMU-C from 1974 to 1980, and untreated sanitary wastewater from the facility
From 1967 to 1974.
During the 1990 Fhase I RFI, 20 soiI samples were collected from locations at WMU-D. The soil
samples were collected continuously at 2-Foot intervals from land surface to the water table
depth. The highest total VOC concentration reported was 131 lig/kg and the remaining detections
were relatively low. VOCs were detected in 12 of the 20 soil samples and PCE was the most
Frequently detected compound.
1.2.5 WMU-E: Treatment Area and Filtration Pit
WMU-E is located north of the machine shop building and south of Slow Creek. This location is
also the location of WMU-F (Chemical Treatment Building), which is discussed below in Section
1.2.6. WMU-E received wastewater from anodizing, passivating, nickel plating, and zinc
phosphating processes. This system was classified as a treatment/ storage/disposal Facility under
40 Code of Federal Regulations Fart 265.1. The WMU-E wastewater treatment system was
constructed in 1980 and included the following components:
■ Two 1,000-gallon lined concrete storage and treatment tanks;
■ One 1,000-gallon concrete effluent storage tank;
CSmith RC RA Facility Investigation Report 1-3

Introduction
■ Two 200-gallon plastic treatment tanks;
■ Two lined sand and gravel filter beds;
■ A container storage area; and
■ Two perforated effluent drain lines.
This wastewater treatment system operated from 1980 until 1986. Wastewater entered the
treatment system and was neutralized in the 1,000-gallon lined concrete storage and treatment
tanks. The neutralized wastewater was then pumped into the two, 200-gallon treatment tanks
where polymer was added to aid flocculation. Subsequently, the wastewater was pumped into the
sand and gravel filter beds. The sludge from the filter beds was placed in drums after the sludge
had drained and the drums were stored in the container storage area. Treated water obtained
from the filter beds entered the 1,000-ga11on concrete effluent storage tank that discharged
through the two perforated effluent drain lines. One drain line extended laterally for
approximately 75 feet beneath the onsite baseball field to the east. The other drain line extended
laterally for approximately 125 Feet beneath the parking lot to the west.
Closure activities for WMU-E were performed from 1986 through 1988. The closure included
removal of the wastewater treatment system and subsequent soil sampling and analysis. The
drain lines were also excavated and the underlying soils sampled. The analyses performed for soil
included the Toxicity Characteristic Leaching Procedure and analyses for metals in addition to
analyses for total VOCs. The soil analytical results did not indicate releases in the locations
sampled. Clean closure certification based on the soil data was submitted in early 1988. On
August 8, 1990, the North Carolina Department of Environment, Health & Natural Resources
accepted the clean closure certification.
1.2.6 WMU-F: Chemical Treatment Building
WMU-F was constructed over the top of the WMU-E location in 1986 following the closure of
WMU-E. A wastewater treatment system consisting of pH adjustrnent, precipitation, flocculation,
and filtration technology was decommissioned in 2008 and replaced with a water re -use system.
Wastewaters from chrome anodizing, zinc phosphating, passivating, electroless nickel -plating,
and aqueous cleaning operations are now treated via ion -exchange technology and returned to
the processes for re -use. This system is entirely closed -loop and does not discharge any effluent
to the Town of Murphy publicly owned treatment works (PGTW).
1.2.7 WMU-G: Percolation Pit
WMU-G is located west-northwest of the main building and adjacent to the 2007 building
addition. It was reported that the percolation pit received plant runoff and mop water from the
plant. The mop water was derived from mopping the floor in the plant. The pit was approximately
16 feet deep, 50 feet long and 20 feet wide. According to plant personnel, the percolation pit had a
concrete wall on the east side and the remainder of the walls and the bottom were earthen. The
pit was used until 1986, at which time it was filled with soil.
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Introduction
Soil sampling was performed at this unit during 198E for the Phase I RFI. Two soil borings were
completed within the pit with soil samples collected continuously at 5-Foot intervals from 9.5 Feet
below land surface to about 20 feet below land surface. Total VDC concentrations ranged from
below detection to 14,82E µg/kg. PCE, 1,1,1-TCA, xylenes, ethyl benzene, and acetone were all
detected at concentrations over 1,000 µg/kg.
Based on the soil sample results, an SVE system was installed at the percolation pit in March
1990. Five vapor extraction wells were installed and screened between 11 to 1B feet below land
surface. Seven air inlet wells were placed at the periphery of the percolation pit.
Regolith monitoring well MW-12 is located near the northwest corner of WMU•G. Samples from
this monitoring well routinely contain VOCs at concentrations over 1,000 µg/L. However, it is
inconclusive whether some or all of the VOCs at this location originate from WMU-G because of
potential migration in groundwater from WMU-A and WMU-B. This unit may represent a source
of VOCs to groundwater.
1.2.8 WMU-H: Polishing Pond
WMU-H is located in the northwest portion of the property. The pond was in operation from 1974
until 1991, The pond received effluent from a sanitary wastewater treatment system; the
discharge from the polishing pond was to Slow Creek, which was authorized by a National
Pollutant Discharge Elimination System permit. The sanitary wastewater treatment system was
located immediately adjacent to the polishing pond and consisted of two steel USTs set on
concrete pads. This system was taken out of service in 1991 when the sanitary wastewater from
the facility has converted to direct discharge to the Town of Murphy PQTW.
In 1991, the polishing pond and treatment tanks were closed. The two tanks were removed and
were observed to be in good condition upon removal. Reportedly, the two tanks were to be put
into service at another facility. The concrete pads beneath the tanks were left in place. The
excavation was backfilled with soil derived from a nearby onsite area.
Prior to polishing pond closure, a sludge sample was collected from the pond. The sludge sample
contained several VOCs and the total VOC concentration was 569 µg/kg. PCE was reported at 320
µg/kg. Following sludge sample collection, soil excavated during the treatment system tank
removal was mixed with the sludge. Although not stated explicitly in the closure report, it appears
that the sludge was not removed and the pond was backfilled along with the tank excavation pit.
According to the closure report, the closure of the wastewater treatment system and the polishing
pond did not require regulatory approval.
1.3 Previous Groundwater Actions
The subsurface lithology beneath the site consists of a single aquifer comprised of three
interconnected hydrogeologic zones, including the regolith zone, the transition zone, and the
bedrock zone. The regolith is the uppermost zone and is composed primarily of unconsolidated
saprolite and alluvium in stream valleys and Flood plains. The transition zone between regolith
and the bedrock typically consists of partially weathered rock, and groundwater in the transition
zone is in Full hydraulic connection with the regolith. This zone primarily includes the more
weather -resistant rock types present in the Murphy Marble and is characterized by alternating
CDM 1-5
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Introduction
rock layers and fractures. The bedrock beneath the site is the Murphy Marble and is the lower
zone of groundwater interest. The site lithology is described in greater detail ill Section Z and
Section 5.
Monitoring wells and recovery wells were installed during multiple phases of work from 1986 to
2003, as shown in Figure 1-2. Groundwater investigations were initiated at the site in 1986
during the closure of WMU-C, when three groundwater monitoring wells [MW-1, MW-2R, and
MW-3] were installed and VOCs were discovered. VOCs were also discovered in the facility's
water supply well (IW-1) in 198G. Supply well IW-1 was completed as an open -rock bore to a
depth ❑f 400 feet and was cased to a depth of 80 feet. Eight additional monitoring wells (MW-4
through MW-11) were installed and tested by SCS in May 1987, and a water treatment system
was installed For the facility water supply well as an I in 1987.
In addition, the North Carolina Department of Natural Resources and Community Development
began sampling private water supplies in the Peachtree community in 1987. VOCs above the
proposed action levels were reported in two residential supply wells located immediately north
of the facility across Slow Creek. Carbon filter systems were installed on seven water supplies.
VOCs above the proposed action levels were not detected in supply wells located adjacent to the
Facility to the east, west, or south. In 1990, a water supply line was extended to provide properties
to the east and north of the Facility with potable water From the Town of Murphy.
A Phase I RFI report submitted in 1990 by SCS (October 1990) documented the installation of
monitoring wells MW-4 through MW-22 and MW-26. Monitoring wells MW-23 through MW-25
had not been installed off site because access permission could not be obtained. The report
identified the presence of VOCs, primarily TCE, in onsite groundwater in both the regolith and
bedrock zones. The report also concluded that the groundwater migration direction in these
zones on site was to the northwest and that additional investigation was necessary.
A Phase 11 RFI was performed and reported in 1991 by SCS [September 19911. This investigation
was focused on assessment of groundwater to the north of the facility. Three monitoring wells
(MW-23, MW-24, and MW-25) were installed across Slow Creek to the north of the facility. These
wells were completed in the alluvium of the Slow Creek stream valley [alluvial valley]. SCS had
intended to install bedrock wells, but difficult drilling conditions prevented the successful
completion of these wells as bedrock wells. SCS concluded in the 1991 Phase lI RFI report that
VOCs in groundwater appeared to originate from WMU-B and WMU-G and migrate to the
northwest toward Slow Creek. The report was inconclusive as to the origin of the offsite VOCs to
the north of the site in the new monitoring wells and the residential wells.
Supply well IW-1 was pumped and the groundwater treated tinder an IM until 1994. A second
groundwater recovery system was installed in 1989. This system consisted of a recovery well
(EW-1) installed adjacent to MW-5 that was completed in the regolith. This well continually filled
with silt and became inoperable. As a result, MW-5 was used for recovery purposes instead of
EW-1.
In August 1995, a system consisting of recovery well RW-1D and VER well RW-1S was installed
and MW-5 was taken offline. This system remains in operation. Samples collected from RW-1S
From 2005 through 2007 contained TCE at a range of 70,000 to 110,000 micrograms per liter
CDM 1-6
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Introduction
(µg/L), TCE concentrations in RW-1 D, which is screened in the upper bedrock and located within
10 feet of RW-1 S, ranged from 2,000 to 4,800 µg/L.
Monitoring wells MW-27 and MW-28 were installed in July 1995. Monitoring wells MW-29
through MW-32 were installed in June 2000 to further assess the distribution of VOCs in the
vicinity of MW-28. In response to increasing VOC concentrations in groundwater samples
collected from monitoring well MW-28, a second VER system consisting of two wells (RW-2 and
RW-3) was installed in 2001 next to Slow Creek. This system remains in operation.
In the VER system, groundwater is pumped From the well and a pneumatic vacuum is applied to
the well head. The vacuum can enhance groundwater recovery by increasing the capture zone
and simultaneously extracting vapor containing VOCs From surrounding soil. The groundwater is
treated by an air stripper and discharged to the Town of Murphy POTW.
In October 2002 and March 2 00 3, investigations of regolith groundwater focused on the
northwest corner of the site, The work included offsite investigation using direct -push technology
(DPT) to install 11 temporary monitoring wells (Arcadis G&M, May 2003). These wells were
installed to depths ranging from approximately 15 to 30 Feet below land surface. Based on the
VOC analyses from these wells, it was concluded that the extent of VOCs had been delineated in
this area to the depths of the investigation.
1.4 Project Objectives
RFI work was previously reported by SCS and included the 1990 Phase I RFI and the 1991 Phase
II RFI. In 2005, the site status was revisited with regard to the need of additional subsurface data
to support future remediation planning efforts. Based on remediation planning data gaps, the
need for additional RFI work was identified and this work was the subject of the current RFI. The
objectives established for the current RFI are consistent with the objectives of the Order and were
intended to enhance the existing information For the site and refine the understanding of the site
Features and subsurface characteristics for groundwater remedy purposes. This RF1's objectives
are summarized as follows:
■ Determine the extent of VOCs in regolith and bedrock groundwater (off site and on site).
a Develop a further understanding of the hydrogeologic conditions associated with the
migration and fate of the VOCs in groundwater.
■ Assess the distribution of VOCs in Slow Creek.
■ Identify groundwater users in the site vicinity and perform VOC analyses for potentially
susceptible locations.
■ Develop a conceptual hydrogeologic model for the site.
■ Support the development of the risk assessment.
■ Support the preparation of the CMS.
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Introduction
1.5 Project Scope
The scope of work for the current RFI was designed to address the project objectives summarized
above. During the implementation of the current RFI, data were obtained that lead to additional
work phases. A total of three work phases were conducted during the course of the current RFI
and were referred to as Phase 1, Phase 2, and Phase 3, as described in Sections 1.5.1, 1.5.2, and
1.5.3 below. Additional assessment activities were conducted after Phase 3 of the RFI and the
initial submittal of this RFI Report, These activities are described in Section 1.5.4.
RFI Phases 1 through 3
In August 2005, C D M Smith Inc., formerly Camp Dresser & McKee Inc. (CDM), submitted an RFI
Work Plan Addendum for additional investigation activities (CDM, August 2005). The work plan
tasks were intended to enhance the existing information For the site and refine the understanding
of the site features and subsurface characteristics For groundwater remedy purposes. Although
multiple phases of RFI work were not envisioned, the initial results were inconclusive and Further
work was necessary. Therefore, the work conducted pursuant to the August 2005 work plan is
referred to as Phase 1 in this RFI report. Based on the information obtained from Phase 1,
additional assessment and data collection needs were identified and fulfilled in Phase 2 pursuant
to RFI Work Plan Addendum I — Revision 1 (CDM, April 2007), issued April 24, 2 00 7, and
approved by the EPA on May 8, 2007. Additional data collection was also implemented associated
with Scope of Work — "Phase III" RFI Investigation (CDM, August 22, 2007) an expanded scope of
work (CDM, October 31, 2007), which received EPA approval and is referred to as Phase 3 in this
report. Surface water sampling was also performed as part of Phase 3 according to the Surface
Water Sampling and Analysis Plan (CDM, January 18, 2008).
The scopes of the Phase 1 to Phase 3 investigations are summarized in Table 1-2 and described
in greater detail in the following subsections. Figure 1-3 shows the investigation locations, which
are subdivided by the media and location of interest (e.g., groundwater in the regolith zone and
bedrock zone) in the following discussions.
1.5.1 Phase 1
The purpose of Phase 1 was to gain information For optimization of a groundwater remedy and to
complete the delineation work for the site. The specific activities that were conducted included a
bedrock investigation, an offsite regolith investigation, and an evaluation of impact to indoor air
quality from potential subsurface vapor intrusion at the operating Facility. These activities are
discussed further below.
Regolith Groundwater Screening Investigation
The initial task identified in the August 2005 work plan addendum was affsite screening for VDCs
in regolith groundwater. The objective was to assess VDCs in groundwater north of Slow Creek in
the regolith zone using DPT. Ten borings were advanced using DPT equipment, and groundwater
samples were collected for held screening and laboratory analyses for VDCs. Each sample was
screened on site for total chlorinated ethenes using the Color-Tec method to gain real-time data
to guide and modify subsequent DPT and monitoring well installation locations, as necessary.
CSPmith RC RA Facility Investigation Report 1-g

Introduction
Regolith Groundwater Investigation
After obtaining the offsite VOC screening data, three permanent monitoring wells (MW-33, MW-
34, and MW-35) were installed off site to depths corresponding with the base of the regolith zone.
The objective was to verify VOC distributions and obtain water level data for potentiometric
surface mapping.
Bedrock Groundwater Investigation
Nine exploratory borings were drilled to verify the bedrock surface topography and to assess the
physical character of the transition zone and bedrock zone. Seven of the locations (S-1 through S-
7) were on the northwest boundary of the site, which is downgradient of the previously identified
VOC source areas and where data gaps existed for bedrock. The other two borings (S-8 and S-9)
were co-]ocated with offsite regolith wells MW-33 and MW-34 north of Slaw Creek. Six of the
exploratory boring locations were deepened to isolate bedrock fractures and completed as
permanent bedrock monitoring wells; these included onsite wells MW-36 through MW-39. Offsite
borings S-8 and S-9 were completed as bedrock wells MW-40 and M W-41. Exploratory borings S-
1, S-3, and S-4 were secured and retained as open -bore wells for potential future use.
Temporary Monitoring Well Abandonment
The 11 temporary monitoring wells installed near the northwest boundary of the facility during
2002 and 2003 were abandoned. These wells were considered to be redundant in consideration
of new permanent monitoring wells being installed.
1.5.2 Phase 2
The results of the Phase 1 investigation presented additional data gaps based on the observed
VOC distribution and hydrogeologic conditions in regolith and bedrock north of Slow Creek. In
response, additional work was identified for Phase 2 to fill the data gaps that existed beyond the
current extent of investigation.
Regolith Groundwater Investigation
One permanent monitoring well was installed onsite (MW-49) and three permanent monitoring
wells (MW-42, MW-46, and MW-4$) were installed off site. These wells were installed to depths
corresponding with the base of the regolith zone. These wells were required to further assess the
distribution of VOCs in regolith groundwater and to support potentiometric surface mapping.
Bedrock Groundwater Investigation
On permanent monitoring well was installed on site (MW-50) and three permanent monitoring
wells (MW-43, MW-44, and MW-47) were installed offsite. These wells were required to further
assess the distribution of VOCs in bedrock groundwater, to determine the depth to bedrock, and
to support potentiometric surface mapping.
Water -Ilse Survey/Water Supply Sampling
An initial survey of private water supply wells was conducted over the area being investigated in
Phase 2 to establish locations for possible future monitoring. Following the survey, water samples
were collected for VOC analyses from two private water supplies.
CSPmith RC RA Facility Investigation Report 1-y

Introduction
1.5.3 Phase 3
The results of the Phase 2 investigation did not fill all of the data gaps identified from Phase 1.
Phase 2 wells installed downgradient to the west and northwest (MW-42, MW-43 and MW-48)
contained VOC concentrations that exceeded the federal Maximum Contaminant Levels (MCLs)
far drinking water. In response, additional work was identified for Phase 3 to fill the data gaps
that existed beyond the previously defined extent of investigation.
Regolitlt Groundwater Investigation
Two permanent regolith monitoring wells (MW-52 and MW-54) were installed off site at the base
of the regolith cone to assess the presence and extent of VOCs in the regolith to the west and
southwest of the site. MW-52 was installed west of the site beyond Slow Creek and MW-54 was
installed southwest of the site.
Bedrock Groundwater Investigation
Four permanent bedrock monitoringwe] Is were installed to further assess the extent of VOCs in
bedrock to the west and southwest of the site, MW-51 (paired with regolith well MW-52) and
MW-53 were installed in downgradient positions west of Slow Creek. MW-45 was installed on the
southwest corner of the site and was paired with existing regolith wells. MW-55 (paired with
regolith well MW-54) was installed to the southwest of the site. Down -hole geophysical logging
and rock coring were also performed during this phase. To provide additional coverage For the
coring and geophysical logging, exploratory boring S-3 was also deepened by caring and
geophysical logging was performed. Geophysical logging was also performed on one private
supply well (PW-228) that was not in use and accessible.
Water -Use Survey/Water Supply Sampling
An expanded survey of water supply wells and springs was completed. The survey identified
more than 40 water supply wells and 1 spring that was being used as a water supply. The
identified locations were subsequently sampled for VOC analyses.
Surface Water Sampling
Surface water monitoring along Slow Creek has historically focused on the stream reach in the
immediate vicinity of the site. Additional Slow Creek sampling locations farther downstream were
included as part of the Phase 3 RFI. Surface water samples were also collected from several of the
tributaries to Slow Creek. A total of 15 surface water and 2 spring samples were collected for VOC
analyses along Slow Creek and from within the alluvial valley.
1.5.4 Additional Investigation Activities
Following Phase 3 of the RFI and the initial submittal of this report, several additional assessment
activities were completed as summarized below and in Table 1-3. These activities support the
RFI objectives identified in Section 1.4 above, and some also supported design for additional IMs.
For the purposes of this report, these additional investigations are all considered part of this RFI,
and the associated procedures, results, and conclusions are included in this report. This RFl
Report supersedes the previous technical memorandums and reports noted below that were
provided to EPA.
CSPmith RC RA Facility Investigation Re port

Introduction
Onsite Source Screening Investigation
In January and February of 2009, an onsite source screening investigation was performed to
evaluate whether VOCs remain in soil at concentrations that are indicative of an ongoing source of
VOCs in groundwater. To allow rapid screening in the field, membrane interface probe (MIP)
screening was performed at 50 locations. Based on the M1 P results, soil characterization sampling
was performed at 22 locations and multiple depths using direct -push soil sampling techniques
and laboratory analyses. Screening and sampling locations are shown on Figure 1-4. The results
From this investigation were previously provided to EPA in the Onsite Source Screening
Investigation Technical Memorandum (CDM, April 2009).
Additional Soil Assessment
I March 2010, additional soil assessment activities were performed to collect additional data in
support of a risk assessment, including background and metals data, and to confirm that no
potential sources of ongoing groundwater contaminants exist beyond those that have already
been identified during previous assessment activities. This assessment included collecting soil
samples From 33 soil borings and 7 background locations with subsequent laboratory analyses.
Each sample was analyzed for VOCs and a site -specific list of metals consisting of antimony,
arsenic, chromium, cobalt, and nickel. The soil boring locations are shown on Figure 1-5, and the
background locations are shown on Figure 1-6. The results From this investigation were
previously provided to EPA in the Additional Soil Assessment Technical Memorandum [included
as part of July 2010 RFI Report submittal].
West Groundwater Flow Evaluation
I October and November of 2010, an investigation was performed to evaluate possible
groundwater flow from the site to the west-southwest into an area that includes former supply
wells that have contained VOCs. This evaluation included potentiometric surface mapping, aquifer
performance tests, geophysical logging, and vertical VOC profiling focused on former supply wells
PW-16, PW-22A, PW-22B, PW-23, and PW-39. Locations involved in this evaluation are shown on
Figure 1-7. The results of this evaluation were previously summarized for EPA in the West
Groundwater Flow Evaluation Technical Memorandum [CDM, March 2011)-
WMU-B Investigation
Three investigations were conducted to assess the lateral and vertical extent of VOCs in regolith
and bedrock groundwater near WMU-B and to support design for an IM in this area. The first
investigation was performed in April and May of 2011 and included completing 13 soil borings
and 7 monitoring wells. These locations are shown on Figure 1-8. This investigation also
included soil and groundwater sampling at multiple depths for vertical profiling,
The results of the first investigation indicated that the lateral and vertical extent of VOCs had not
been fully defined. 'Thus, a step -out investigation was conducted from September through
December of 2011. This investigation included completing an additional 23 soil borings and 10
monitoring wells. These locations are shown on Figure 1-8. Quick turnaround laboratory
reporting was performed to guide goring and we]Is locations and help ensure that the lateral and
vertical extent of VOCs was fully defined prior to demobilizing. Similar to the first investigation,
the step -out work included vertical VOC profiling. It also included completing angle borings and
wells underneath buildings. The results from the first two investigations were previously
CDM 1_1�
Smith RCRA Facility Investigation Report

Introduction
summarized for EPA in the Waste Management Unit S Step -Out Investigation Technical
Memorandum (CDM Smith, March 2012).
A third and final investigation was conducted in October and November 2012 to further delineate
the extent of VOCs underneath the main plant buildings and to support design for a thermal
remediation IM. This investigation involved completing an additional 12 soil borings at locations
inside the main plant buildings, as shown on Figure 1-8. Similar to the second investigation, this
phase of work included quick turnaround laboratory reporting and vertical VOC profiling of both
soil and groundwater to the depth of bedrock. The results of the third investigation are
summarized in this report.
Offsite Groundwater Investigation
From September through November of 2011, an offsite groundwater investigation was conducted
to further assess groundwater quality and migration between the site and former supply wells to
the west-southwest. This investigation was also conducted to support design for an offsite
groundwater IM, more specifically to provide data necessary to select locations for installation of
reinjection wells and to install reinjection wells. The investigation followed up on previous work
performed for the west groundwater flow evaluation and included a geophysical survey,
installation of six monitoring wells, installation of eight reinjection wells, aquifer testing, and
groundwater sampling. Locations associated with this investigation are shown on Figure 1-9.
Geophysical survey transect locations are shown an Figure 1-10. The results from this
investigation were previously summarized for EPA in the Offsite Investigation / injection Well
Installation Technical Memorandum (CDM Smith, March 2012).
CDM 1-12
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i` n viro nm en to 1Setting
Section 2
Environmental Setting
2.1 Land Use
The vicinity of the site is known as the Peachtree Gomm unity of Cherokee County, North Carolina.
Land use in the site vicinity is primarily rural residential [Figure 2-1]. In addition to residences,
the rural residential properties typically include uses such as pasture for livestock, hay fields, and
garden plots. The site is bounded to the north by Slow Creek with rural residential properties
located to the north and the west. The site is bounded to the south by commercial and industrial
land uses, including a service station, a hardware store, and a manufacturing facility.
Greenlawn Cemetery Road and additional rural residential properties are located farther to the
south and southwest, The site is bounded to the east by North Carolina Highway 141. Rural
residential properties are also located to the east. Multi -residential developments exist to the
northwest and south of the site. A school is located southeast of the site. Churches and properties
owned by religious affiliations are present throughout the community. Cherokee County owns
and operates a community renter located west of the site. The road right-of-ways along North
Carolina Highway 141 and Greenlawn Cemetery Road are owned by the State of North Carolina.
2.2 Topography and Drainage
The site is located on the border of a stream valley that drains to the south-southwest into the
Hiawassee River (refer to Figure 1-1). The Hiawassee River forms the hydraulic base level for the
local drainage basin and is at an elevation of approximately 1,550 feet National Geodic Vertical
Datum 1929 (NGVD). The site is at an average elevation of about 1,640 feet NGVD. The stream
valley is flanked to the southeast and northwest by mountains with elevations of more than 2,000
feet NGVD.
Figure 2-2 is a topographic map of the site vicinity, The surface topography and drainage on site
is primarily to the north toward Slow Creek. Slow Creek flows to the west past the site and then
flows south to ultimately join Peachtree Creek, which discharges to the Hiawassee River. The
south portion of the site drains into a swale that exits the southwest corner of the property into a
broad, enclosed topographic depression. A drainage ditch has been excavated through the
depression to allow drainage down to Greenlawn Cemetery Road. West of the depression, the
surface drainage continues west through a ditch and flows into Slow Creek south of Greenlawn
Cemetery Road.
2.3 Regional Geology
The site is located in the Blue Ridge Physiographic Province (the Blue Ridge] in the southwest
corner of North Carolina [Figure 2-3]. The Blue Ridge predominantly consists of metamorphic
rock of sedimentary origin that is between the Valley and Ridge Physiographi c Province to the
northwest and the Piedmont Physiographic Province to the southeast. The Blue Ridge is
invariably mountainous and forms an elongated belt across North Carolina that follows a
southwest to northeast trend. The regional geological formations that appear on Figure 2-3 are
CDM
Smith RC RA Facility Investigation Re port

Environmental Setting
summarized in Table 2-1. The site is located within a geologic subdivision of the Blue Ridge
referred to as the Murphy Belt_ The Murphy Belt consists of four sedimentary rock units Chat have
been metamorphosed. The stratigraphic sequence of these units is a subject of debate. These
units are summarized in Table 2-1, in descending order, by the most commonly accepted
stratigraphic sequence..
The Murphy Belt is generally considered to he a syncline and includes a major thrust fault a] Ong
its axis referred to as the Mary king Mountain Fault. Rock layers from the southeast have been
thrust up over the rock to the northwest to form the fault. In addition to thus thrust fault, these
rocks have been subjected to four separate deformation events, and folds, joints, and fractures are
common. Fault planes, joints, and fractures formed during early deformation events may be
sealed because the rocks were plastic during deformation and mineralization has occurred since
that time. Three of the four Murphy Belt stratigraphic units are mapped at land surface in the site
vicinity. The undifferentiated Murphy Marble/Andrews Formation is indicated at the site with the
Brasstown Formation being mapped to the northeast. The remainder of the surrounding area is
mapped as the undifferentiated Mineral Bluff Formation/Nottely Quartzite.
Based on the regional geologic map, these stratigraphic units dip to the southeast from about 40'
to 60'. The dip angle of the fault plane is not reported, but the dip direction of the fault plane is to
the southeast.
2.4 Hydrogeology
Groundwater in the Blue Ridge occurs in the unconsolidated regolith that overlies the bedrock
formations and in the bedrock. Part of the precipitation that does not runoff to streams infiltrates
the regolith and recharges the water table. Groundwater in the regolith typically flows laterally in
the topographic downhill direction and ultimately enters a stream or river valley where the
groundwater typically discharges to the stream. At higher elevations above the stream or river
valley, some of the regolith groundwater infiltrates downward to recharge the bedrock aquifer.
The groundwater flow direction can be less predictable in bedrock than in the regolith on a
localized scale. Bedrock groundwater also tends to flow in the topographic downhill direction and
toward the stream and river valleys. However, groundwater in bedrock primarily occupies
fractures and joints, and these features can form preferential flow paths that cause localized
disturbances in the flow paths.
Because: the mineralogy of Murphy Marble is primarily water-soluble calcium carbonate,
fractures and joints in the bedrock formation can be enlarged into solution channels by the
circulation of groundwater, The dissolution of the soluble minerals along fractures can have
several effects. One undesirable effect can be the formation of depressions and sinkholes as the
regolith erodes into solution channels and cavities in the bedrock. Alternatively, the solution
channels can provide a reliable water source for wells that penetrate the channels. However,
because not all of the marble formation is water soluble, silt and mud may occupy the channels,
making them less suitable for water supply purposes. A review of water wells and discussions
with drillers revealed that a reliable water supply can usually be obtained in the site vicinity with
a drilled and cased well completed to a depth of 150 feet below land surface and completed in the
marble Formation. However, if a mud and silt bearing fracture or an iron -rich zone is encountered,
the upper zone of the marble will have to be cased off and deeper water bearing zones will have
CSmith RC RA Facility Investigation Report -2

Environmental Setting
to be drilled to provide access to suitable water supplies. Typically, the number and the size of
fractures decrease with depth. As a result, the deeper wells may require drilling several hundred
feet deeper to obtain a sufficient water supply, and the deep well bore typically serves to store
groundwater that slowly recharges the well.
Some groundwater supplies in the area have poor water quality due to the presence of iron. This
water quality problem is not a characteristic of the marble formation and is more closely
associated with form atians that contain sulfide minerals. Sulfide minerals are reported in the
literature for the Nantahala Formation and also occur in the slate of the Mineral Bluff Formation.
CDM 2-3
Smith RCRA Facility Investigation Report

Procedures
vestigation Report
Section 3
Procedures
This section describes the investigation procedures used during the RF1. All data collection was
performed in accordance with approved work plans and the Environmental Investigations
Standard Operating Procedures and Quality Assurance Manual, November 2001, EPA, Region 4,
Science and Ecosystem Support Division, Athens, Georgia. This manual was superseded in
November 2007 by the Field Branches Quality System and Technical Procedures, and
investigation activities performed after November 2007 followed the new procedure and
guidance documents.
3.1 Subsurface Investigations
Geologic logs and well construction records were prepared for all drilling activities. Appendix A,
which is segregated by investigation activity, contains geologic boring logs and well construction
diagrams for all borings and wells. Table 3-1 provides well construction summary data for the
wells installed during all RFI activities.
3.1.1 Regolith Well Installation
Regolith wells were installed using multiple techniques. During Phase 1, three offsite monitoring
wells (MW-33, MW-34, and MW-35) were installed using a casing advancer method. This method
installs 6-inch, inside diameter (ID) casing using an eccentric air -hammer bit (ODEX). The ODEX
bit is placed through the casing and expands to a larger diameter (several inches) once below the
casing when rotated. The cuttings are removed from the bare hole by the air stream and piped
through a diverter to a rolkoff container. Rotating the bit in the opposite direction collapses the
bit so that it can be withdrawn from the casing. The casing was advanced to the bedrock surface
and the ODEX bit retrieved. The well construction materials were then installed and the annulus
backfilled as the casing was retrieved.
The six regolith wells installed during Phases 2 and 3 (MW-42, MW-46, MW-48, MW-49, MW-52,
and MW-54) were installed using conventional hollow -stem augers. The augers were drilled to
the top of bedrock. The well construction materials were then installed and the annulus backfilled
as the augers were retrieved. These regolith wells were constructed using the following
materials-.
■ Two-inch ID, polyvinyl chloride (PVC) slotted monitoring well screen (O.D1-inch slots);
■ Two-inch ID, PVC monitoring well riser pipe;
■ Silica sand pack, #1 standard sand;
■ Bentonite chips;
■ Cement/bentonite grout;
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■ Flush -mount, bolt -down cover with locking well cap or above -grade, locking security
cover; and
■ Concrete pad.
The bentonite chips were allowed to hydrate for a minimum of 8 hours before grout installation.
The grout was installed using the tremie-pipe method and allowed to cure a minimum of 12 hours
before well development. All down -hole drilling tools were decontaminated by steam cleaning at
a central onsite location between each drilling Iocation.
Regolith wells installed as part of WMO-S investigation activities were done using conventional
hollow -stem augers. These wells were constructed using either 2-inch or 4-inch diameter,
Schedule 48 PVC riser flush threaded to 8.01-inch slotted Schedule 40 PVC screen. A filter pack
consisting of #1 Standard or #2 Standard sand was installed to 3 Feet above the screen. A 3-foot
bentonite annular seal was placed above the filter pack and hydrated with potable water. The
remainder of the borehole annulus was backfilIed to near ground surface with bentonite and
Portland cement grout. Each monitoring well was completed with a flush -mounted steel vault,
expandable well cap, well identification placard, and a 2-foot by 2-foot concrete pad.
During the offsite groundwater investigation, one regolith monitoring well (MW-60) was installed
using hollow -stem augers. The remaining regolith monitoring well (MW-62), regolith reinjection
wells (INj-2, -4, -6, and -8), and two transition zone monitoring wells (MW-56 and -57) were
installed using Symmetrix to ensure deeper penetration into the transition zone. The Symmetrix
technology consists of advancing a steel casing using an air -hammer hit that is integrally locked
within the casing. While drilling, the air -hammer hit can be selectively disengaged from the casing
to allow a smaller diameter open bore to be completed below the casing. Alternately, the steel
casing can be grouted in place or retrieved as a conventional well screen and riser are installed
through the casing along with annular fill materials.
3.1.2 Exploratory Borings
Nine exploratory borings (5-1 through S-9) were drilled during )CFI Phase 1 to verify the depth to
bedrock and assess the physical character of the transition and bedrock zones. These borings
were drilled using the ODEX system described above. However, instead of installing a regolith
well upon encountering bedrock, the exploratory borings were drilled deeper to set the 6-inch ID
surface casing into competent rock and the drill bit was retrieved. The 6-inch ID steel surface
casing was then lifted approximately 1 foot off the bottom of the borehole and the surface casing
was filled with cement/bentonite grout. A casing plug then forced the grout from the surface
casing at the bottom of the borehole. Once the grout had cured, the annulus was topped off with
cement/grout.
A 6-inch diameter borehole was then extended through the surface casing into the underlying
rock for an additional depth of approximately 20 feet on the exploratory borings. Six of the
exploratory borings (S-2 and S-5 through S-9) were deepened and completed as permanent
bedrock monitoring we]Is, as described below. The three exploratory borings not completed as
monitoring wells (S-1, S-3, and S-4) were secured by installing a locking cover on the 6-inch
surface casing.
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3.1.3 Bedrock Well Installation
Fourteen bedrock wells were installed during RFl Phases 1 to 3. Six of these wells were installed
in the boreholes constructed For the exploratory borings (MW-36, MW-37, MW-38, MW-39, MW-
40, and MW-41). Eight bedrock monitoring wells (MW-43, MW-44, MW-45, MW-47, MW-50, MW-
51, MW-53, and MW-55) were installed in bore hoIes constructed in an identical manil eras the
exploratory borings using ODEX drilling to install the surface casing and air -hammer drilling
below the surface casing to construct a 6-inch diameter borehole for well installation. Rock coring
was performed for three of the wells (MW-45, MW-51, and MW-53), and the core holes were
reamed to a 6-inch diameter for well installation. The bedrock wells were constructed using the
fallowing materials:
■ Six-inch ID, carbon steel surface casing;
■ Two-inch ID, PVC slotted monitoring well screen (0.01-inch slots);
■ Two-inch ID, PVC monitoring well riser pipe;
■ Silica sand pack, # 1 standard sand;
■ Bentonite chips;
■ Cernent/bentonite grout;
■ Flush -mount, bolt -down cover with locking well cap or above -grade, locking security
rover; and
■ Concrete pad.
Grout For the surface casing was cured for a minimum of 12 hours before bedrock drilling or
coring resumed. The bentonite chips were hydrated for a minimum of 8 hours before grout
installation. The grout for the well surface casing was installed using the tremie-pipe method and
cured for a minimum of 12 hours before well development. All down -hole drilling tools were
decontaminated by steam cleaning at a central onsite location between each drilling location.
Bedrock wells were also installed as part of the WMU-B and offsite groundwater investigation
activities. WMU-B bedrock wells were installed using sonic drilling [Gus Pech and Versa -Drill
rigs] and constructed in the same manner as for the WMU-B regolith wells. Offs ite investigation
bedrock monitoring wells and reinjection wells were installed using Symmetrix.
3.1.4 Rock Coring
Rock coring was conducted at four locations (S-3, MW-45, MW-51, and MW-53) during RFI Phase
3 to assess the physical character of the bedrock and assess fractures. The coring was performed
on boreholes that had been cased with 6-inch ID steel surface casing, The rock coring used a HQ -
size core bit. This core hit produced a core hale with an approximately 4-inch diameter, which
was large enough to allow for the geophysical logging described in Section 3.1.7.
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3.1.5 Onsite Source Screening
During the onsite source screening investigation, M I P screening was performed to rapidly
identify the presence of VQCs in soil and groundwater. M I P screening involves using direct -push
technology to drive a vapor point. At pre -determined depth intervals, typically 0.1 feet, a vapor
sample is collected for screening analysis. The vapor sample is collected by first heating the probe
to mobilize VOCs in the formation. The vapor sample is then drawn into the tubing across the
membrane under a vacuum. The vapor sample is returned to the surface through the tubing and
then measured by three laboratory -grade detectors: an electron capture detector (ECD), a
photoionization detector (PID), and a Flame ionization detector (FID). The F I D will ionize
essentially any VOC but is the least sensitive detector. The PID is more selective and will ionize
select chlorinated ethene VOCs and aromatic VOCs. The PI is more sensitive than the FID. The
E C D detects only halogenated compounds, and the EC data are valuable For assessing
chlorinated VOCs. The ECD is the most sensitive detector. The probe also provides data related to
the formation materials through measurement of the penetration rate, down pressure,
temperature, and formation electrical conductivity. Plots from the MIP screening are provided in
Appendix B.
3.1.6 Soil Borings
Soil borings were drilled and associated soil sampling was performed as part of the onsite source
screening investigation, additional soil assessment, and WMU-B investigation activities. Borings
completed as part of the onsite source screening investigation and additional soil assessment
were done using a Geoprobe® with the exception of background soil locations, which were done
using a hand auger. Borings for the WMU-B investigation were performed using a Geoprobeo
where access was limited (e.g., power lines, inside main buildings, etc.), hollow -stem augers, and
sonic. The angle borings were completed using sonic. All soil borings were abandoned by
backfilling with bentonite chips or a mixture of neat Portland cement and powdered bentonite.
Soil borings installed through asphalt were completed with a concrete patch, and tile Mooring was
restored to original condition for borings completed inside the main buildings.
3.1.7 Geophysical Logging
Following rock coring during Phase 3 of the RFI, geophysical logging was conducted on S-3, MW-
45, MW-51, and MW-53. Most of the core holes drilled for logging purposes partially in -filled with
sand and gravel from fractures and the full core depth could not be logged. Geophysical logging
was also conducted on one private water supply well (PW-2213]. This well was logged because it
was within the area of interest, not in use, and was easily accessible. Additional geophysical
logging was performed during the west groundwater flow evaluation on wells PW-16, PW-22A,
PW-23, and PW-39.
The suite of geophysical logs included standard electric logs, natural gamma, caliper, acoustic
televiewer, and electromagnetic flow meter. Appendix C contains the geophysical logs for both
investigations.
3.1.8 Geophysical Survey
As part of the offsite investigation, a very low frequency (VLF) electromagnetic survey of the
study area was completed to identify potential preferential groundwater migration pathways in
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bedrock, The VLF electromagnetic survey method uses the magnetic components of the
electromagnetic Feld generated by military radio transmitters, transmitting in the frequency
band 15 kHz to 30 kHz. The magnetic field lines produced by the radio transmitters are horizontal
with the Feld lines forming concentric circles around the antenna. Electrically conductive
structures above, below or at the surface of the earth locally affect the direction and strength of
the field generated by the transmitted radio signal. A secondary electrical current can be induced
into a conductor, assuming that certain conditions are fulfilled, producing a weak secondary
magnetic field that can be measured and analyzed. These secondary magnetic fields are often
produced by vertical or tilted subsurface features such as fractures, contacts between rock types,
and Faults.
For induction to occur with the subsequent production of a secondary magnetic field, the
conductor should be aligned towards the transmitter. However, a secondary magnetic Feld will
only he generated if the target is large enough and has a higher electrical conductivity than the
surrounding material. A higher electrical conductivity is typical of a fracture or highly jointed
formation surrounded by more competent, less fractured rock. The length of the target should
exceed ISO feet and it should have a depth of more than 30 feet to be identified. However, the
width or thickness of the target can be as little as 1.5 feet to be identified.
The equipment used for such a survey measures both the field strength and the phase
displacement of the secondary Feld generated by the conductor. The ratio between the vertical
and the horizontal components, in percent, is measured. As the primary field from the transmitter
is horizontal, the 'normal' reading will be zero, even in the presence of horizontally lying
conductors.
The instrument used For this survey was a Wadi VLF Instrument manufactured by Abem of
Bromma, Sweden. The Wadi measures both the vertical and horizontal components of the
magnetic VLF field. By dividing the vertical by the horizontal component, it calculates the tilt
angle of the resultant field, which is the tilt of the polarization ellipsoid. Both the real and the
imaginary components are measured.
Before the data is stored, the measured values are automatically corrected for minor antenna tilt
errors. The horizontal antenna field is used as a reference for determining phase displacement.
Electromagnetic anomalies are generally identified as either highly conductive or highly resistive.
A high percent value is associated with a high electrical conductivity feature and a negative
percentage is associated with a resistive feature. ]Narrow, high and symmetrical peaks in the data
may indicate buried utilities.
The VLF data were downloaded and stored electronically from the Wadi. The data were then
processing using RAMAGTM Software (Walen, P.M., VLF Survey Planning and Interpretation
Software For the Ahem Wadi and other instruments that record VLF dip angle measurements,
Version 2.2 - USB, Copyright 2003). The geophysical survey data for each transect are provided in
Appendix D.
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3.2 Groundwater Sampling
The groundwater sampling From monitoring wells during the RFI was performed according to the
procedures used far the existing groundwater monitoring program. Water levels were measured
before well sampling to determine the groundwater depth and the static well volume. The water
levels were recorded using an electric water level indicator and recorded to the nearest a.01-foot
increment. The wells were purged using a submersible, direct current powered pump fitted with
either disposable polyethylene tubing or Teflon tubing. Field parameters (pH, specific
conductivity, and temperature) were measured and recorded during well purging. The
groundwater samples were collected after a minimum of three static well volumes had been
purged and the field parameters had stabilized. After well purging, the groundwater samp]es
were collected using disposable bailers. Before sample collection, the bailer was rinsed three
times with groundwater from the well. Pre -preserved sample containers were supplied by the
laboratory. immediately Following sample collection, the sample vials were labeled and packaged
on ice. Samples were shipped to the analytical laboratory under standard chain -of -custody
procedures, and analyzed far VOCs using SW-846 Method 8 2 6 0 B (EPA, November 1986).
With the exception of the submersible pump, electric water level indicator, and dedicated Teflon
tubing, all sampling equipment was new/disposable and did not require decontamination. The
submersible pump and electric water level indicator were decontaminated after each use using a
laboratory -grade soap solution wash and triple rinsing with analyte-free water.
Groundwater sampling from boring locations was performed using Hydropunch sampling
techniques. Samples were collected from hollow -stem augers and direct -push borings using a
stainless -steel screen -point and bailer that were decontaminated between sample intervals. Sonic
boring samples were collected by installing a 5-foot stainless -steel screen at the sample interval
connected to a 2-inch PVC riser. A packer was installed just above the screen to seal the sample
interval. A pump with a flow rate controller was lowered to the bottom of the screen. The screen
and pump were decontaminated between sample intervals, and new tubing was used for each
sample. Hydropunch samp]e intervals from the sonic borings were purged a minimum of la
minutes prior to sample collection to evacuate drilling water, consisting of potable water
obtained from a plant fire hydrant.
3.3 Water -Use Survey and Water Supply Sampling
A water -use survey was performed for the site vicinity during Phases 2 and 3 of the RFI- This
survey began with an initial mailing notice to the individual properties within the survey area,
followed by a visit and interview with the property owners and occupants. The requested survey
information -included the number/locations of wells and springs, uses of wells/springs, and well
construction details (diameter, materials, drilling method, depth, and installation date). This
information was used initially to select we] Is for groundwater sample collection and VOC
analyses. However, all identified water supplies that used wells or springs within the survey area
were ultimately sampled during the RFI, and select water supplies continue to be monitored on a
regular basis.
The water supply wells fitted with plumbing were purged and sampled using the discharge outlet
that was nearest to the wellhead. This location was typically an outlet on the pump piping at the
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wellhead. The well was purged at a moderate rate for a period of approximately 15 minutes.
During purging, the purge volume was recorded along with measurements of pH, conductivity,
and temperature. Before sample collection, the flow rate was lowered to prevent aeration of the
sample stream, and the sample containers were filled directly from the discharge outlet.
Immediately following sample collection, the sample vials were labeled and packaged on ice.
Samples were shipped to the analytical laboratory under standard chain -of custody procedures,
and analyzed for VOCs using EPA SW-846 Method 8260B.
Some water supply wells that were no longer in use were sampled and did not have operable
pumps. These wells were purged in the same manner as the monitoring well purging and
sampling described above using a submersible pump. During purging, the purge volume was
recorded along with measurements of pH, conductivity, and temperature. The samples were
collected using a disposable polyethylene bailer. Before sample collection, the bailer was rinsed
three times with groundwater from the well. Immediately following sample collection, the sample
vials were labeled and packaged on ice. Samples were shipped to the analytical laboratory under
standard chain -of -custody procedures, and analyzed for VOCs using EPA SW-846 Method 8260B.
3.4 Surface Water Sampling
At each sampling location, direct dipping of the sample container into the stream was performed
while wading in the stream. The samples were collected from near the center of the stream
channel and from the deepest stream depth observed. Because wading can cause the suspension
of sediments, the sampling was initiated at the downstream station and progressed in an
upstream direction. In some instances, the stream was sampled from the stream bank and wading
was not required.
Each sample was collected directly into the sample vial while facing upstream and without
disturbing the sediment or displacing the preservative from the pre -preserved sample vials.
Immediately following sample collection, the sample vials were labeled and packaged on ice.
Samples were shipped to the analytical laboratory under standard chain -of -custody procedures,
and analyzed for VOCs using EPA SW-846 Method 8260B. Ancillary data collected from each
surface water station included global positioning system coordinates, water temperature, pH, and
conductivity. The water parameter measurements were taken after sample collection by placing
the probe directly into the stream channel.
3.5 Soil Sampling
Soil samples obtained as part of the onsite source screening investigation, additional soil
assessment, and WMU-B investigation activities were collected from each boring using a 2-foot
long, split -spoon sampler and a combination of Macro -Core® and split -spoon samplers for
borings that were continuously sampled. Soil samples were collected using Encore samplers at
various depth intervals. In some cases, a portion of the soil recovered in the split -spoon or Macro -
Core® samplers was placed in plastic bags to measure organic vapor levels in the headspace.
These samples were allowed to equilibrate for approximately 10 minutes and then screened
using a hand-held P I D to determine which samples should be sent to the laboratory for analysis
and/or which samples required quick turnaround to guide where additional samples needed to
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Procedures
be collected. PI readings for borings where screening was performed are included on the boring
logs in Appendix A.
Samples were shipped to the analytical laboratory under standard chain -of custody procedures,
and analyzed for VOCs and/or metals using applicable EPA SW-846 methods. Select soil samples
were also submitted for geotechnical testing, including particle size distribution by American
Society for Testing and Materials (ASTM) standard D4464, grain size by ASTM standard D422,
and organic carbon content by the Walkley-Black method.
3.6 Aquifer Performance Testing
During the west groundwater flow evaluation, short duration aquifer performance tests (APTs)
were completed for former supply wells PW-16, PW-22A, PW-23, and PW-39 using the in -place
pumps and plumbing. The APTs consisted of pumping each of the supply wells independently,
recording the pumping rates, and collecting water levels from select surrounding wells. The
pumped water was treated through an activated carbon vessel and discharged to land surface. To
assess the effectiveness of the treatment process, a sample of the treated groundwater effluent
from PW-23 was laboratory analyzed for VOCs and no compounds were detected.
During the offsite groundwater investigation, MW-60 and -61 were tested using a Ste p-drawdown
approach. These wells were each pumped at rates of approximately 1.5, 3.5, and 5 gallons per
minute (gpm). The water levels in the wells were recorded using a pressure sensitive water level
transducer and data logger. Hydrographs for the offsite groundwater investigation test results are
included in Appendix E. Testing was not conducted at monitoring wells MW-62 and MW-63 as
these wells would not sustain a sufficient flow rate for testing. This outcome was expected for
these two wells based on the geophysical survey results.
Constant rate discharge tests were also completed during the offsite groundwater investigation
on the reinjection wells, with water IeveIs recorded in adjacent monitoring and reinjection wells.
These tests were performed at flow rates ranging from approximately 3 to 8 gpm, depending on
the well response to pumping. The hydrographs for the pumping wells and observation wells are
included in Appendix E.
3.7 Investigation Derived Waste
Soil cuttings generated during drilling activities were placed in either 55-gallon drums or roll -off
containers. At the conclusion of each investigation phase, samples were collected from the drums
and/or roll -off containers, coniposited, and sent to the analytical laboratory For waste
characterization analyses and profiling. Following profiling, the soil was transported and
disposed of through a licensed non -hazardous or hazardous waste disposal company, as
appropriate. Water from investigation activities (e.g., drilling, well purging, etc.) was collected in
55-gal lon drums and/or frac tanks and disposed of via the ansite groundwater treatment system.
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Results
Section 4
Results
This section of the RFI report presents the results for each investigation phase of the RFI. Due to
the large number of samples and results, the laboratory data are summarized in data tables by
investigation phase. The full laboratory reports that contain the results for all RFI analyses are on
the compact disk in Appendix F. Due to the dates of some of the investigation phases and related
subsequent investigations, figures are not included for each investigation phase. For example, the
groundwater concentration maps presented at the end of the section are intended to represent
current conditions and supersede groundwater data collected as part of Phase 1 of the RFI.
4.1 Phase 1
4.1.1 Regolith Groundwater Screening Investigation
Ten borings were installed using DPT and groundwater samples were collected for field screening
and laboratory analyses for VOCs. Each sample was screened on site for total chlorinated ethenes
using the Color-Tec method to provide real-time data. Table 4-1 lists the results of the oils ite
screening. Table 4-2 lists the results of the laboratory analyses and Figure 4-1 presents the
posted target VOC concentrations.
The DPT borings were advanced to the depth of penetration refusal and the groundwater samples
were then collected. The screening data obtained using Color-Tec provided acceptable correlation
based on a comparison with the laboratory data. The VOC results from the screening were used to
select locations for permanent monitoring well installation in the area across Slow Creek.
Although the locations where VOCs were detected during the screening were consistent with the
historical VOC distribution, the depth to refusal for DPT- 17 of 116 feet below land surface
indicated a greater depth to bedrock than expected based on the limited data across Slow Creek.
4.1.2 Regolith Groundwater Investigation
Three offsite regolith wells [MW-33, MW-34, and MW-35] were completed in June and July 2006.
Groundwater sampling from these wells was conducted in August 2006 and again in June 2007.
The analytical results for these sample dates are summarized in Table 4-3. TCE was the most
consistently detected VOC in the offsite regolith groundwater samples, and the highest
concentration was 76 µg/L at MW-34, which is located at the north boundary of the Phase 1
investigation area. TCE was also reported at a concentration of 70 µg/L in MW-35.
4.1.3 Bedrock Groundwater Investigation
Four on site bedrock wells (MW-36 through MW-39) were installed near the site boundary and
two offsite bedrock wells CMW-40 and MW-41] were installed north of Slow Creek. These wells
were installed in June and July 2006. Groundwater sampling from these wells was conducted in
August 2006 and again in June 2007. The analytical results for these sample dates are
summarized in Table 4-3.
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The highest VOC concentrations in the bedrock groundwater near the site boundary were
reported in the northwest corner of the site. MW-37, located on the west site boundary, had the
highest TCE concentration at 27,000 gg/L in June 2007. ❑ffsite bedrock well MW-40 was installed
in the expected direction of groundwater migration in bedrock but contained only trace
concentrations of VOCs. However, MW-41, located north of the site and across Slow Creek, had a
TCE concentration of 1,400 Vg/L in June 2007. Both wells MW-40 and MW-41 encountered a
coarse -grained sand and gravel zone 1n the regolith, with a depth to bedrock of approximately
120 feet. These VOC results in bedrock groundwater coupled with the unexpected depth to
bedrock prompted completion of additional investigation work
4.2 Phase 2
4.2.1 Regolith Groundwater Investigation
One onsite regolith well (MW-49) and three offsite regolith wells (MW-42, MW-46, and MW-4B)
were installed in May and June 2007. Groundwater sampling from these wells was conducted in
]une 2007. MW-42 and MW-48 were sampled again in August 2007. The analytical results for
these sample dates are summarized in Table 4-4.
The Phase 2 monitoring wells established the extent of VOCs in regolith groundwater to the north
and northeast of the site. However, TCE was detected at low concentrations above the MCL in
MW-42 and MW-48 groundwater samples in the downgradient direction along Slow Creek to the
west.
4.2.2 Bedrock Groundwater Investigation
One onsite bedrock well (MW-50) and three offsite bedrock wells (MW-43, MW-44, and MW-47)
were installed in May and June 2007. Groundwater sampling from the wells was conducted in
June 2007. MW-43 was sampled again in August 2007. The analytical results For these sample
dates are summarized in Table 4-4.
The Phase 2 monitoring wells established the extent of VOCs in bedrock groundwater to the
north. However, TCE was detected at a low concentration above the M C L in the MW-43
groundwater sample in the downgradient direction along Slow Creek to the west. TCE was also
detected in the northeast corner of site in MW-50 at a concentration of 18 µg/L.
4.3 Water -Use Survey and Water Supply Sampling
4.3.1 Water -Use Survey
A water -use survey was conducted for the site vicinity during Phase 2 of the RFI. The survey area
boundary was initially selected to include the drainage basin in the immediate area of the ongoing
RF1 investigation. Because additional groundwater data were obtained during the (CFI, the water -
use survey area was expanded twice. Figure 4-2 shows the areas included in the three water -use
surveys and the locations of the identified water supplies.
4.3.2 Water Supply Sampling
The water supplies were sampled during four sampling events. In general, the four sampling
events were conducted to include supplies identified during expansions of the survey and in
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Results
response to users of water supplies. Eight private wells and a water supply spring were sampled
August 30-31, 2007. An expanded water supply sampling event was performed on September 20-
21 and again on October 9-12, 2007. Follow-up sampling was conducted on October 19, 2007, to
collect samples from four supplies at the owner's request. A water supply well (PW-36A) installed
while the water supply sampling was being performed was sampled in November 2007, along
with two additional wells. Table 4-5 gives the VOC results From the alcove sampling events .
It should be noted that additional water supplies beyond the area shown in Figure 4-4 were
identified and sampled through requests within the community. However, these additional
sample results are not considered pertinent to the RFI objectives given that these additional
sampling points are outside of the RFI study area. These additional sampling efforts were
conducted by the Cherokee County Health Department, and the laboratory results are given in
Appendix F.
4.4 Phase 3
4.4.1 Regolith Groundwater Investigation
Two offsite regolith wells (MW-52 and MW-54) were installed From November 2007 to January
2008. MW-52 was sampled in November 2007 and MW-54 was sampled in February 2008. The
analytical results for these sample dates are summarized in Table 4-6.
TCE was detected below the MCL in regolith groundwater within the alluvial valley at an
estimated concentration of 0.33 µg/L 1n MW-52, but was not detected west of the site in MW-54.
Based on the available data, no additional investigation was proposed for the regolith zone off site
to Fulfill the RFI objectives.
4.4.2 Bedrock Groundwater Investigation
One onsite bedrock well (MW-45) and three oMite bedrock wells (MW-51, MW-53, and MW-S5)
were installed From November 2007 to January 200S. Groundwater sampling was performed in
November 2007 for MW-45, MW-51 and MW-53. MW-55 was sampled in February 2008. The
analytical results for these sample dates are summarized in Table 4-6.
TCE was detected in bedrock groundwater within the alluvial valley at MW-51 and MW-53 at
concentrations below the MCL, TCE was not detected in MW-55 west of the site. Based on the
available data, no additional investigation was proposed for the bedrock zone off site to fulfill the
RFI objectives.
4.4.3 Surface Water Sampling
Surface water samples were collected from Slow Creek and its tributaries at 14 locations (CMP-1
through CMP-4 and SW-1 through SW-10) in February 2008. Two springs were also sampled as
part of the surface water sampling program (SP-26 and 5P-51). An additional surface water
sample was collected at the request of a property owner (SW-11). The analytical results are
summarized in Table 4-7. The upstream surface water samples on Slow Creek (CMP-1 and CMP-
2) had no VOCs detected. Beginning with station CMP-3 in Slow Creek, VOCS were detected at the
remainder of the Slow Creek sample stations. Downstream of station SW-6, the VOCs in Slow
Creek were below the MCLs.
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Results
Samples from the Slaw Creek tributary called Messer Creek (SW-1, SW-2, and SW-5) had 170 VOCs
detected. Samples From drainage bitches that originate within the fields surrounding Slow Creek
(SW-4, SW-7 and SW-8) likewise had no VOCs detected, with the exception of an estimated
concentration below the reporting level of 0.63 µg/L at SW-4, which is at the confluence of a
tributary with Slow Creek.
Sampling point SW-9 is at the discharge of a spring (SP-25 in Figure 4-2) that is used as a water
supply. Sampling results from SW-9, with TCE of 1.7 µg/L, are consistent with results from the
spring (Table 4-5). Field observations during the February 2008 surface water sampling did not
indicate any other springs in or along the main stem of Slow Creek or its tributaries within the
study area.
4.5 Onsite Source Screening Investigation
Membrane Interface Probe Screening
Detailed plots of the ECD, PID, and F1 D results by depth for each MIP boring are provided in
Appendix B. These plots also include conductivity, pressure, and temperature changes by depth.
As shown in Appendix B, the detector results are presented in millivolts (mV). While these results
cannot be directly correlated to VOC concentrations in soil, in general, locations with higher mV
results are indicative of areas with higher VOC concentrations and vice versa. For evaluation
purposes, the following criteria were used for each detector response:
• High range: values are greater than 1 x 107 mV;
• Medium range: values less than 1 x 107 mV but greater than 5 x 106 mV,
r Low range: values less than 5 x 106 mV.
The corresponding results are summarized in Table 4-8. Cross -sections For the detector
responses are shown in Figures 4-3 through 4-9.
The area with the highest MIP results was at WM.U-B (MIP-14), the former UST. The ECD results
for this location are low from the surface to a depth of 10 feet, which is expected based on
previous soil excavation and UST removal. However, the results increase with depth up to 25 feet
below ground surface (bgs) before tapering off, as indicated by the FID data. The estimated depth
to water at MIP-14 is 22 feet, indicating that source -level concentrations could be located above
and below the water table.
MIP results indicative of a potential source were also observed near WMU-A, the former drum
storage area. Borings MIP-4, -5, and -b show the highest detector responses in this area.
Characterization Sari Sampling
Based on the MIP results, 22 locations were selected for characterization soil sampling, as
summarized in Table 4-9. The sampling results are presented in Table 4-10. Total V 0 C
concentrations for select locations are also posted on the MIP cross -sections in Figures 4-4 and 7.
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As shown in these figures, the soil sampling results correspond fairly well with the M I P results.
The highest VOC concentrations were detected at SB-15 (MIP-14) at a depth of 16 feet bgs. Total
VOC concentrations in soil at this location were as high as 343 milligrams kilogram (mg/kg) and
were an order of magnitude higher than at any other location. Consistent with the MIP results, the
concentrations increased with depth and were somewhat limited in lateral extent.
The highest VOC concentrations in the WMU-A area were detected at S B - 9 (MIP-5) at a depth of
16 feet logs. The total VOC concentration in soil at this location and depth was 4.4 mg/kg.
No compounds were detected in the southwest property boundary sampling locations. However-,
the depth to refusal was less than 10 feet in these locations. VOCs in groundwater that may have
originated from an offsite source south of the facility may be migrating through the bedrock at
this point in a direction of southeast to northwest.
4.6 Additional Soil Assessment
Table 4-11 and Table 4-12 present a summary of the laboratory results from the additional soil
assessment for VOCs and metals, respectively. Table 4-11 only includes those compounds that
were detected in at least one sample.
Most VOC results were non -detect or showed estimated concentrations below the laboratory
reporting limit. Three locations (EU1- SB2, EU2-SB1, and EU2-SB2) revealed total VOC
concentrations in soil greater than 0.1 mg/kg, and all three locations are within the horizontal
extents for WMUs A [Drum Storage Area] and B (UST).
In general, the results for metals in soil were similar to those For the background locations. Only
arsenic was detected in soil at concentrations above the most stringent EPA Industrial Soil
Regional Screening Level (RSL) [November 2012] for each metal. This includes all of the
background locations, indicating that arsenic is naturally present in soil in this area above its RSL.
Arsenic was detected at a higher concentration than the maximum background location at 11 of
the 33 boring locations. The average arsenic concentration in soil for the background samples
was 3.6 mg/kg, and the average arsenic concentration in soil for the exposure unit samples was
3.7 mg/kg.
4.7 West Groundwater Flow Evaluation
Potentiometric Surface Mapping
An initial round of groundwater levels was recorded from select wells to establish the prevailing
groundwater potentiometric surface in the regolith and bedrock zones during the evaluation. The
water level data and calculated potentiometric surface elevations are included in Table 4-13.
Figure 4-10 and Figure 4-11 include interpreted potentiometric surface contour maps for the
regolith and bedrock zones, respectively.
As indicated on Figure 4-10, the regolith zone potentiometric surface indicates a groundwater
flow direction to the north-northwest. This flow is consistent with historical interpretations.
Figure 4-10 also indicates a strong influence from the onsite groundwater extraction system, and
in particular, the significant effect of extraction in the regolith zone at both RW-3 and RW-4.
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Results
Figure 4-11 indicates groundwater flow to the northwest in the bedrock zone. This
potentiometric surface pattern is also consistent with historical interpretations, The addition of
bedrock potentiometric surface data from supply wells PW-23 and PW-39 further confirms the
high bedrock potentiometric surface elevations in the southwest corner of the site that have been
observed on a routine basis in the past. However, a relatively steep hydraulic gradient exists
between PW-23, PW-39, and MW-45 toward PW-22A. This observation indicates that PW-22A
had a bedrock potentiometric surface that was lower than would be expected based on the
surrounding well data. Figure 4-11 also indicates a strong influence from the onsite groundwater
extraction system, and in particular the significant effect of extraction in the bedrock zone at RW-
S.
Former Supply Well APTs
Table 4-14 summarizes the wells and well construction details for the wells used during the
APTs. Table 4-15 summarizes the test schedule for each supply well along with APT summary
data. Figure 4-12 through Figure 4-15 include the APT pumping rates and hydrographs for the
observation wells and for the pumping wells. The water level records in the hydrographs were all
normalized with the water levels referenced to zero immediately prior to pump operation.
Negative water levels on the hydrographs indicate a drop in the water level. A summary of the
results from each APT is provided below.
PW-23 APT
The APT for supply well PW-23 was completed first. ❑uring this APT, excessive drawdown was
experienced at a flow rate of approximately 6 gpm, and the flow rate was reduced to a sustainable
flow rate of approximately 1 gpm. As shown on Figure 4-14, the pumping at PW-23 likely
influenced the water level in PW-39, which is approximately 160 feet away in the upgradient
direction. The water levels in wells MW-16, MW-17, and PW-22A also appear to decrease during
the time that PW-23 was pumping at the higher flow rates. The PW-23 pumping rates are shown
on Figure 4-14. PW-23 was also used as an observation point for the APTs on PW-22A and PW-39.
PW-39 APT
Prior to the placement of the water -level recorders, it was apparent that supply well PW-39 had
been pumped, as indicated on Figure 4-15. It is unknown who pumped this well prior to the test
but it was likely the owner. This pumping caused the water in PW-39 to be rising from recovery
prior to the PW-39 APT. Based on the hydrographs, it appears that wells MW-16, MW-17, MW-4S,
and PW-22A were all slightly influenced by the pumping. PW-39 only experienced 1.7 feet of
drawdown at a flow rate of 8.5 gpm, indicating a more transmissive formation that inferred from
the remainder of the former supply wells tested.
PW-22A APT
The water level in PW-22A equilibrated at approximately 60 feet of drawdown at a flow rate or
approximately 1 gpm. MW-16, MW-17, and MW-45 all appear to be slightly influenced by the
pumping of PW-22A.
PW-16 APT
PW-16 was pumped at a flow rate of approximately 4 gpm and equilibrated with approximately
30 feet of drawdown. Based on the hydrographs on Figure 4-12, it appears that the water levels in
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wells MW-45 and MW-37 declined slightly during the pumping of PW-16. It should, however, be
recognized that the MW-37 water level changes were also affected by the onsite extraction well
system. MW-45 and MW-37 are 1,000 feet from PW-16.
Supply Well Geophysical Lagging
Geophysical logging results are summarized in Table 4-16. A summary of logging observations is
also discussed further below and includes the wells logged during both Phase 3 of the R F I and the
West Groundwater Flow Evaluation. The hill geophysical logs are included in Appendix C.
PW-16 Geophysical Lames
PW-16 has reported total depth of 265 feet but the geophysical logging found the total well depth.
to he 247 Feet. it is common for supply wells to infill with sediment over time up to the level at
which the well pump intake is able to entrain and remove the sediment. This level of sediment
removal by the pump is variable but is typically within about 5 Feet of the primp intake.
The open -bore portion of the well that was available for geophysical logging was a total of 4 feet
and covered the interval from the casing bottom, at 243 feet, to 247 feet. As a result, insufficient
open bore was available to collect meaningful geophysical -logging data.
PW-22A Geophysical Lags
PW-22A was found to have a total depth of 615 Feet with 6-inch diameter casing installed to a
depth of 234 feet. Because PW-22A was open for the full depth, this well provided good
information for the deeper portions of the formation using geophysical logging. However, because
the upper 234 feet of the formation were cased, data could not be collected for the upper
formation using geophysical logging.
Thin fractures and "bedding" planes were detected throughout the PW-22A well bore using the
acoustic televiewer [Figure 4-16A]. The features reported as "bedding" planes are actually the
metamorphic rock foliation planes. Groundwater can migrate preferentially along foliation planes
because continuous layers of higher permeability can be developed along the foliation planes. A
very high percentage of the fractures and foliation planes are clustered on Figure 4-16A and dip
in the north-northeast to east-northeast direction at angles ranging From 300 to 650. Potential
zones of increased porosity were also indicated by the formation electrical logs as zones of
increased electrical resistivity. These zones are further supported as having higher relative
porosities by the decreased gamma count, which can be an indication of lower density rock. A
rough bore -hole wall can develop during the drilling of lower density rock, and higher density
rock tends to result in a smoother bore -hole wall.
Vertical groundwater flow within the well bore was downward at the 253-foot depth. At the 438-
foot depth, the vertical flow log data indicated that groundwater was Flowing upward through the
borehole, and to the total well depth of 605 feet, the upward flow rate increased with increasing
depth. Groundwater flowing vertically in the borehole apparently reentered the formation
between the 253- and 438-foot depths under non -pumping conditions. The observed #lows were
very low [0.006 gpm on average].
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PW-22B Geophysical Lags
PW-22B was found to have a total depth of 246 feet with 6-inch diameter casing installed to a
depth of 130 feet. PW-22B provided good information for the accessible portions of the
formation. Fractures were detected throughout the PW-22B well bore using the acoustic
televiewer (Figure 4-16A). Most of the fractures on Figure 4-16A dipped to the south at angles
ranging from 100 to 750.
PW-23 Geophysical Logs
PW-23 was found to be a 30-inch diameter bored well with a concrete casing installed to the total
depth. The reported total well depth ranges from 110 feet in 2007 to over 200 feet in 2010. The
total well depth was found to be 47 feet, which is the approximate Ievel of the pump intake for the
well. The total depth of this well is unknown.
PW-39 Geophysical Logs
The well owner of PW-39 reported a total depth of 161 feet but the geophysical logging found the
total well depth to be 83 feet with 6-inch diameter casing installed to a depth of 60 feet. PW-39
has a very rough borehole wall, indicating alternating layers of competent rock and soft rock.
Separated foliation planes were also detected by the acoustic televiewer, but fractures were not
detected. As shown on Figure 4-16A, the foliation and rock layering dip directions were clustered
from the east-southeast to the south-southeast and dipped at 2011 to 4011. The vertical flow meter
data for PW-39 indicated upward flow throughout the well bore. The lowest upward flow rate
was measured at the 57- and 70-foot depths, where the groundwater could be reentering the
formation. The observed flows were very low (0.006 gpm on average).
MW-45 Geophysical_ Lugs
MW-45 had a total depth of 75 feet with 6-inch diameter casing installed to a depth of 44 feet. The
total drilled well depth was 95 feet but infilling of the well bore with sediments derived from
Fractures and voids filled the lower 20 feet of the well. Fractures were detected throughout the
MW-45 well bore using the acoustic televiewer (Figure 4-168). Most of the fractures on Figure 4-
16B were dipping approximately southwest to south at angles ranging from 2011 to 6011. Larger
fracture and voids were encountered during drilling below the depth of inFlling based on the
drilling action. The vertical flow Iog far MW-45 indicated upward flow at the 49- and 61-foot
depths and slight downward flow at the 68.5-foot depth. The observed flows were very low and
0.004 gpm on average.
5-3 Geophysical Logs
S-3 was a geotechnicaI rock boring that had a total depth of 100 feet with 6-inch diameter casing
installed to a depth of 24 feet. The total drilled well depth was 100 feet and the lower portion was
cored. 5-3 had a low fracture density. The fractures detected in 5-3 had two primary dip
directions; from the north to the northeast and from the west to the south (Figure 4-16B). The dip
angles ranged from less than 101) up to 55,,. The vertical flaw log for MW-45 indicated upward
flow at the 28- and 38-foot depths and no flow detected at the 47-foot depth. The observed flows
were very low and 0.002 gpm on average.
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Supply Well Sampling and Vertical Profiling
Supply well sampling and vertical profiling were performed in select supply wells to characterize
the groundwater chemistry and VOCs with depth. Vertical profiling was completed on former
supply wells PW-22A and PW-22B. Sampling was also completed for former supply wells PW-16,
PW-23, and PW-39. However, packers could not be used for these wells to provide vertical profile
data because of the well construction limitations and/or sediment infill.
The depth intervals that were sampled using vertical profiling were selected based on an initial
review of the draft geophysical logs. The depth intervals were isolated using double packers and
groundwater samples were collected Following standard purging of the packer system. The
samples were analyzed for VOCs, geochemical parameters, and other constituents that were
considered to be indicative of potential source areas and groundwater chemistry.
Tetrahydrofuran was added to the analyses as a marker for PVC glue/solvent. This compound
being present along with VOCs such as acetone and 2-butanone (MEK) provides relatively
conclusive evidence of a PVC -related VOC source. Total organic carbon, total coliform, E. toll, and
"methylene blue active substance" analyses were included as indicators of contamination from
sources such as septic systems.
The groundwater data from the vertical profiling are summarized in Table 4-17. Table 4-18
includes summary statistics for wells located on site along the northwest site boundaries. These
statistics are included to establish patterns between the VOCs migrating from the site and the
VOCs reported in the former supply wells. Historical VOC data From the subject supply wells were
also summarized to allow Further analysis of select VOC trends over time. Table 4-19 includes the
tabulated trend data, and time -trend plots are shown on Figure 4-17A and Figure 4-17B.
The VOC most consistently detected at the highest concentrations along the site boundary has
been TCE, and it is the most characteristic of the site -derived VOCs. Six additional VOCs have been
detected at frequencies that ranged from approximately 7 5 % to over 95% and included 1,1-
dichloroethene (DCE), PCE, cis-1,2-DCE, 1,1-dicllloroethane (DCA), dichlorodifluoromethane
(Freon 113), and 1,1,1-TCA. Other VOCs that have been detected at lesser frequencies and are of
interest to the supply well data include methyl tert- butyl ether CMTBE), acetone, and MEK, all of
which have been detected at frequencies less than 3% at the site boundaries. Table 4-18 also
includes the average concentration ratios of the VOCs to the average TCE concentrations at the
site boundary. With the exception of cis-1,2-DCE at 10%, the VOC concentrations averaged 3% to
7% of the TCE concentration. The numerical values of the ratios far MT BE, acetone, and M E K are
not considered diagnostic because an insufficient number of detections have been reported for
these VOCs at the site boundary.
PW-16 Groundwater Analyses
Vertical profiling was not performed on PW-16 because of the reduced casing diameters that
would not allow the packers to be installed. This well was sampled in a conventional manner. TCE
was detected at 4.5 µg/L, which was consistent with the historical data. Additional VOCs were
detected at concentrations below the reporting limits including acetone, 1,1,1-TCA, 1,1-DCE, and
PCE. The historical VOC data additionally include low -concentration detections of 1,1-DCA, MEK,
cis-1,2-13CE, and Freon 113.
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TCE has invariably been the VOC detected at the highest concentration in groundwater at PW-16
with the exception of one event when MEK was the only VOC detected. The VOCs present are
consistent with the VOC characteristics near the site boundary and they appear to be site -derived
VOCs. However, it remains likely that acetone and MEK may be related to PVC plumbing
associated with the we11. PW-16 also had high iron from the steel well casing that was disturbed
during pump removal.
PW-22A Groundwater Analyses
Vertical profiling was performed on PW-22A at five depth intervals. Although TCE was detected in
all intervals at concentrations ranging from 29 to 43 µg/L, these concentrations were notably
lower than the historical TCE detections that average approximately 190 µg/L. The most -
probable entry point for the higher concentration VOCs into the well bore is immediately beneath
the casing and the VOCs are likely originating from a shallower zone and migrating downward
between the well casing and the well bore. The lower depth VOCs detected during the vertical
profiling are likely present in the well bore walls throughout the well depth from past leakance
rather than migration to the well through the formation.
Additional VOCs that were in PW-22A from the vertical profiling included 1,1-DCA, 1,1-DCE, MEK,
chloroform, acetone, cis- 1,2-DCE, Freon 113, PCE, tetrahydrofu ran, toluene, and TCE. The
combined detections of MEK, acetone, and tetrahyd ro fu ra n indicate potential contamination From
PVC glue/solvent. The presence of multiple VOCs and the relative concentrations are consistent
with the VOC characteristics near the site boundary, and they appear to be site -derived VOCs.
PW-221B Groundwater Analyses
Vertical profiling was performed on PW-22B at three depth intervals. This well was constructed
in 2007 and VOCs were not detected in this well during the one previous sampling event from
August 2007. This well was never completed with a pump a placed in service for supply
purposes.
TCE was detected during vertical profiling in all intervals at concentrations below the reporting
level of 1 µg/L. Additional VOCs that were in PW-22B included carbon disulfide in one interval
below the reporting limit and tetrahydrofuran in 2 depth intervals at S3 and 88 µg/L. This well is
constructed of glued PVC casing. The limited data do not allow further conclusions related to the
below -reporting -level TCE being site -derived or not.
PW-23 Groundwater Analyses
Vertical profiling was not performed on PW-23 because the well was cased to the bottom of the
well. The casing prevents the installation of the packer system into open portions of the
formation. This well was sampled in a conventional manner. The only VOC detected in this well
from this sampling event was tetra hydro fura n, a VOC associated with PVC glue/so Ivent.
Historically, acetone and MEK have also been detected in this well and are associated with PVC
glue solvent. During October 2009, acetone and MEK were reported at 2,200 and 4,000 1tg/L,
respectively. These concentrations exceed the highest concentrations of acetone and MEK
recorded along the site boundary. TCE, PCE, cis-1,2-DCE, and Freon 113 have never been detected
in PW-23. 1,1,1-TCA was detected duNjig one sampling event at a concentration below the
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Results
reporting limit while 1,1-DCA and 1,1-DCE have been detected in two sampling events at
concentrations near the reporting limit. The presence of these VDCs in PW-23 is not consistent
with the VDC characteristics near the site boundary and they do not appear to be site -derived
VDCs. In addition, PW-23 was found to contain total coliform and E. coh, indicating potential
impacts from the septic system located immediately adjacent to the well.
PW-39 Groundwater Analyses
Vertical profiling was not performed on PW-39 because of the limited length of available well
bore. This well was sampled in a conventional manner, and PCE was the only VOC detected. The
detected PCE concentration was 2.6 gg/L, and this detection is consistent with the historical data
for PW-39. In one previous sampling event, November 2007, MElt and acetone were detected at
Iow concentrations and this was a likely result of PVC glue solvent contamination. TCE, 1,1-DCA,
1,1-DCE cis-1,2-DCE, Freon 113, and 1,1,1-TCA have never heen detected in PW-39. The VGCs
detected are not consistent with the VDC characteristics near the site boundary and they do not
appear to be site -derived VDCs. A release from a source limited primarily to PCE is likely
associated with the groundwater at PW-39 rather than the site -derived plume that is
characterized by a large suite of VDCs.
4.8 WMU-B Investigation
Subsurface Lithology
The regolith zone in the WMU-B investigation area is composed of saprolite with the transition
cone beneath the regolith. The saprolite is unconsolidated and is derived from the in -place
chemical and physical weathering of the Murphy Marble. The soil encountered during drilling
consisted of sandy silt with inter-Iayered zones of silty clay and rock fragments. The transition
zone between regolith and competent bedrock was relatively thin and consisted of partially
weathered rock, and was found to be present at most of the boring locations. During the WMU-B
investigation, the top of the transition zone was defined as the depth at which the penetration
resistance using Standard Penetration Testing was greater than 50 blows per 6-inches of
penetration. This definition was used to facilitate consistent identification of the transition zone
surface during drilling. Soil cores from sonic drilled borings were visually inspected to determine
the top of the transition zone.
The thickness of the regolith zone and depth to the transition and bedrock zones varies across the
WMU-B area. The regolith cone is thickest beneath WMU-B and decreases in thickness west-
northwest across the site. Within the investigation area, the depth from ground surface to the top
of bedrock ranged from 110 feet at boring HP-1 to 25 feet at boring HPBB-11.
Geologic cross section locations for this investigation are shown on Figure 4-18, and the
associated cross -sections are provided on Figures 4-19 through 4-21. Figures 4-19 and 4-20
present cross sections from west to east through the investigation area. A north to south cross
section is presented on Figure 4-21 and includes borings extending beneath the northern and
southern plant buildings.
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Results
Soil Sampling
Tabulated VOC results for all soil samples collected as part of the WMU-B investigations are
provided in Table 4-20. Physical testing (e.g., grain size, moisture, ash, organic matter, sped fir
gravity, soil density, and total organic carbon) results are provided in Appendix G.
Similar to other investigation activities, detected VOCs in the soil samples primarily consisted of
PCE, TCE, 1,1,1-TCA, and 1,1-DCE. The highest reported concentrations of TCE and PCE from each
boring were used to generate isoconcentration contour maps in soil for two depth intervals: the
shallow regolith zone from 20 to 45 feet bgs and the deep zone (greater than 50 feet bgs). 5halIow
regolith zone TCE and PCE isoconcentration maps are provided on Figures 4-22 and 4-23,
respectively. Deep regolith zone TCE and PCE isoconcentration maps are provided on Figures 4-
24 and 4-25, respectively.
Groundwater Sampling
Groundwater sampling for WMU-B included collecting samples from each boring location at 10-
foot depth intervals from 30 feet bgs to the top of bedrock, It also included collecting samples
from all newly installed monitoring wells. Tabulated VOC results for the boring groundwater
sample locations are provided in Table 4-21, and tabulated VOC and metals results for the newly
installed monitoring wells are provided in Table 4-22. General chemistry results for the newly
installed monitoring wells are summarized in Table 4-23, and water duality parameter
measurements are shown in Table 4-24.
isoconcentration contour maps were also constructed as follows:
• Figure 4-26 - shallow (20 to 45 feet bgs) regolith TCE
• Figure 4-27 - shallow (20 to 45 feet bgs) regolith PCE
• Figure 4-28 - deep [> 50 feet bgs] regolith TCE
• Figure 4-29 - deep [> 50 feet bgs] regolith PCE
Due to the limited number of data points, contour maps were not developed for bedrock. TCE and
PCE concentrations in bedrock are shown on Figures 4-30 and 4-31, respectively.
Ground water elevations were measured from aI] of the WMU-B area monitoring wells on 20
December 2011. The groundwater elevations were used to generate the potentiometric surface
maps provided on Figures 4-32 and 4-33 for the regolith zone and bedrock zone, respectively.
The groundwater Flow direction in the WMU-B regolith zone and bedrock zone is northwest
toward Slow Creek and the downgradient recovery wells. This flow direction is consistent with
historical interpretations.
4.9 Gffsite Groundwater Investigation
Geophysical Survey
Appendix D includes the results of the VLF survey for each transect shown on Figure 1-10. For
each data plot, two current density cross sections are provided. The raw VLF data are
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Results
superimposed an the current density cross sections in the form of an X — Y graph with distance
shown on the X axis and the VLF measurements shown on the Y axis. The VLF electromagnetic
data have units of percent, as described in Section 3.1.8. Because the percent is that associated
with the disturbance of the Field, a higher percentage is associated with a "high strength"
electromagnetic anomaly. Several additional terms appear on the data plots that warrant
explanation, as provided below.
In -Phase Data — This is the percentage of the total in -phase response produced by the subsurface
conductor or anomaly and is referred to as the real component.
Quadrature Data—Quadrature refers to the out of phase response measurement and is also
referred as the imaginary component. The imaginary component often provides an indication of
the conductivity of the structure that has been found. If the imaginary component is considerably
lower than the real component, it means that the anomaly is a good conductor. If it is higher, it is a
poor conductor.
Data Filter Depth — Traditionally, VLF measurement displays have been based on the tilt angle of
the field. These curves can be very difficult to interpret because of topographic effects and certain
other factors. Different types of filtering techniques have been used to make the true peaks more
visible. The Wadi uses a well-known filter designed by Karous and Hjelt to clarify the data. The
output from this filter is equal to the current density at a certain depth in the ground.
Electromagnetic anomalies are generally identified as either highly conductive or highly resistive.
A high percent value is associated with a high electrical conductivity feature and a negative
percentage is associated with a resistive feature. Narrow, high and symmetrical peaks in the data
may indicate buried utilities. There is no direct relationship between the colors on the current
density cross sections and the absolute detection of groundwater. The VLF instrument is not a
water detector. The instruments simply detect and map electrically conductive zones in the
subsurface. The colors reflect the degree of conductivity. Red is very conductive, blue is very
resistive. Bedrock that is broken and fractured and contains groundwater is more likely to be
electrically conductive than competent unfractured bedrock.
The interpreted results of the geophysical survey are presented on Figure 4-34. Anomalies that
potentially represent preferential migration pathways were interpreted as being either
"moderate" or "high" intensity. In general, the high intensity anomalies were located to the north
across Slow Creek and moderate intensity anomalies were located west of the site. The moderate
intensities west of the site could possibly be attributed to preferential migration pathways that
were close to horizontal rather than strongly sloped or vertical The high intensity anomalies to
the north presented acceptable targets for further exploration using monitoring wells.
Well Installation
Monitoring Wells
Eight monitoring wells were planned for installation during the offsite groundwater investigation,
The monitoring well locations and objectives are described below.
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■ MW-56 and MW-57 - These transition zone wells were used to investigate the potential
link between the site and offsite wells to the southwest. Access could not be obtained offsite
for MW-57 and this well was relocated on site.
• MW-58 and MW-59 - These bedrock and regolith zone wells were to be used to investigate
potential reinjection well locations downgradient of RW-4. Access could not be obtained
offsite for these locations and these wells were not installed.
■ MW-60 and MW-61 - This bedrock/regolith zone well cluster was to be used to investigate
potential reinjection well locations downgradient across Slow Creek. These well locations
were refined using the geophysical survey data.
• MW-62 and MW-63 -This bedrock/regolith zone well cluster was to be used to investigate
the link between the site and offsite groundwater at MW-41. These well Iocations were
refined using the geophysical survey data.
The installed well locations are shown on Figure I-9. During the drilling of MW-63, a subsurface
collapse occurred that prevented further drilling at this location. The geophysical survey had
indicated a very high intensity anomaly at the selected location, and based on transect T-4, it also
appeared that bedrock was sloping upward to the north. Bedrock well MW-63 was relocated to
the north to a location that appeared to be underlain by competent bedrock, and MW-62 was
located immediately south to a location intended to intersect the edge of the anomaly,
Reinjection Wells
The reinjection well Iocations were finalized based on the results of the geophysical survey, the
information obtained from the monitoring well installation testing, and access considerations. In
addition, the setback requirements imposed by the State's Non -Discharge (injection wells)
permitting regulations were considered. The primary location selection objective was to complete
the reinjection wells in high transmissivity locations that had relatively low VDC concentrations
in groundwater. Based on previous investigations at the site, the locations of higher
transmissivity typically coincide with lower i1DC concentrations in groundwater because of
dilution. The secondary reinjection well location objective was to place the wells as close to the
site boundary as practical to enhance the capture zone From the onsite recovery well system. The
final reinjection well locations are shown on Figure 1-9.
Aquifer Testing
Monitoring Wells
Following well installation, aquifer testing was completed on the new monitoring wells and the
reinjection wells, Because MW-56 and MW-57 were not related to reinjection, aquifer testing was
not performed on these wells. Monitoring wells MW-62 and -63 would not sustain a sufficient
flow rate for testing. MW-62 and -63 were purnped dry at approximately 1.5 gpm. MW-62 was
screened at a shallow depth but at a location interpreted to be beyond the highly transmissive
area based on the geophysical survey. The lack of production from this well verified the
geophysical survey interpretation. MW-63 was intentionally set in competent bedrock and the
boring log did not indicate water -bearing fractures in the screened interval. Although these wells
CDM
Smith RC RA Facility Investigation Report 4-14

Results
do not produce high water volumes, they are considered to be acceptable for groundwater quality
monitoring.
MW-60 and -61 were successfully tested using a step-drawdown approach. These wells were
each pumped at rates of approximately 1.5, 3.5, and 5 gpm. The water levels in the wells were
recorded using a pressure sensitive water level transducer and data logger. Hydrographs of the
test results are included in Appendix E. The estimated specific capacity of MW-60, a regolith well,
is approximately 0.1 gpm per foot of drawdown. The estimated specific capacity of bedrock
monitoring well MW-61 is approximately 0.2 gpm per foot of drawdown. As shown on the
hydrograph for MW-61, the most transmissive zone encountered at this well location was the
transition zone.
Reinjection Wells
Constant rate discharge tests were completed oil the reinjection wells with water levels recorded
in adjacent monitoring and reinjection wells. In general, the observation wells selected were
intended to assess the response to pumping in the pumping well, the regolith/transition zone,
and the bedrock zone. These tests were performed at flow rates ranging from approximately 3 to
S gpm, depending on the well response to pumping. Higher flows were not attempted because the
pumped water required transport to the onsite treatment facility for disposal.
The hydrographs for the pumping wells and observation wells are included in Appendix E. The
estimated reinjection capacities ❑f each reinjection well are included in Table 4-2S. The
reinjection capacities in Table 4-25 assume that the reinjection pressure per gpm is the opposite
of the pumping capacity and that these estimates are valid for relatively low reinjection pressures
and for reinjection rates that are similar to the pumping rates.
Groundwater Monitoring
Groundwater sampling was performed during the aquifer testing on the monitoring and
reinjection wells. An initial sample was collected during the startup of pumping and a second
sample was collected near the end of the pumping. Groundwater samples were also collected
from the new monitoring wells that did not undergo aquifer testing. Table 4-26 includes a
summary of the laboratory data from this sampling.
4.10 Quality Assurance/Quality Control Samples
Quality assurance/quality control (QA/QC) procedures were observed and reported within the
analytical laboratory and for field sampling during the RFI.
4.10.1 Laboratory Analyses
With the exception of one sample, all Iaboratory services were provided by Test America,
formerly known as Severn Trent Laboratories, Inc. Test America performed laboratory analyses
in support of the RFI at their Pittsburgh, Pennsylvania, Savannah, Georgia, and South Burlington,
Vermont laboratories. One sample during the West Groundwater Flow Evaluation was submitted
to EAS Testing Lab in Franklin, North Carolina for bacteriological analysis.
The laboratories followed conventional QA/QC procedures for the laboratory analyses of
environmental samples. Each laboratory maintains internal QA/QC manuals and the appropriate
CSPmith RC RA Facility Investigation Report 4-15

Results
certifications. A case narrative was included with each sample delivery batch that details the
QA/QC results. With very few exceptions, the laboratory data were delivered without data quality
issues.
The most common issues reported were that the associated method blank contained analytes at a
reportable concentration, as indicated by a "B" data qualifier, and that laboratory control sample
and laboratory control sample duplicate results exceeded control limits. Select data were also
reported with the following qualifiers:
■ D - result was obtained by analyzing the sample at a dilution
■ E - result exceeded calibration range
■ F - matrix spike or matrix spike duplicate exceeded control limits
■ H - sample was prepped or analyzed past the specified holding time
• X - surrogate is outside control limits
In some cases, reanalysis was performed by the laboratory to achieve QA/QC criteria. In general,
the common laboratory issues experienced do not affect the results or conclusions presented in
this report.
4.10.2 Field Samples
The types of QA/QC samples collected in the field included trip blanks, field blanks, and blind
duplicate samples. Trip blanks were included in each individual shipping cooler that was used to
store and ship the samples. The results for mast trip blank samples revealed no compounds
detected. A few trip blank samples had minor detections, predominantly of methylene chloride,
below or just above the associated laboratory reporting limit. Methylene chloride is a common
laboratory solvent and is not a primary site -related VOC.
one field blartk was also collected during the initial RFI surface water sampling event, and the
results For this blank were negative. Because all sampling equipment used during the RFI that
contacted the samples was new and disposable or Teflon -coated, equipment rinsate blanks were
not collected.
Dup] icate sample collection was targeted at a rate of 10 percent during RFI Phases 1 through 3.
The number of field duplicate samples collected as part of additional RFI activities varied. Table
4-27 provides a summary of field duplicate results for groundwater and surface water samples.
Table 4-28 provides a summary of field duplicate sample results for soil samples. As shown in
these tables, the duplicate sample results have an excellent degree of agreement with the
environmental samples for both qualification and quantification of compounds.
CDM 4.16
Smith RC RA Facility Investigation Report

Conclusions
Investigation Report
Section 5
Conclusions
5.1 Geology
The subsurface investigations For the site indicate a single aquifer that consists of three
interconnected hydrogeologic zones. These zones are summarized below.
* - Rock types are listed from most to least frequently observed and are commonly interlayered.
The hydrogeologic descriptions above are consistent with literature sources and site
investigations conducted by others since the late 1980s. The current understanding of the
hydrogeology and lithology is based on the results of subsurface investigations conducted by CAM
Smith since 2006.
5.1.1 Regolith Zone Geology
The regolith is the shallowest zone and is composed of two types of materials; saprolite and
alluvium. The saprolite is unconsolidated, is derived from the in -place weathering of the Murphy
Marble and is encountered in areas adjacent to the alluvial valley. The alluvium located in the
alluvial valley includes an upper, Fine-grained layer that appears to be flood -plain -type deposits
and a deeper, coarse -grained layer of sand and gravel alluvial deposits. The fine-grained alluvium
can be difficult to distinguish from saprolite because they can have similar mineral compositions.
CM Sn1ith RCRA Facility Investigation Report
5-1

Conclusions
The coarse -grained alluvium ranges from medium- to coarse -grained sand with gravel, and
boulders are Frequent in this zone.
5.1.2 Transition Zone Geology
The transition zone between the regolith and the fractured bedrock aquifer typically consists of
fractured, partially weathered rack and is typically present at most locations. This zone is usually
thicker at the higher elevations that are not within the alluvial galley. This layer is typically
thinner beneath the alluvial valley where the partially weathered rock has been eroded away by
flowing surface water combined with dissolution.
One exception to the character of the transition zone in the alluvial valley exists immediately
north of the site where layers of rock, from 5- to 25-feet thick, are interlayered with fractures,
from several feet up to 27-feet thick, which contain coarse -grained alluvium. The total thickness
of the transition zone in this area is up to 90 feet. The transition zone in this area has a relatively
high transmissivity in comparison to all of the other hydrogeologic zones observed at the site.
CDM Smith believes that this area is the result of erosion by fluvial processes exposing inclined
rock ledges while deposits of coarse -grained alluvium in -filled between the rack ledges. This type
of erosional and depositional environment can be viewed in modern Blue Ridge rivers toady.
Otherwise, the transition zone primarily includes the mare weather -resistant rock types present
in the Murphy Marble and is characterized by alternating rock layers and smaller- fractures. The
fractures in the transition zone are typically filled with regolith material from above. Evidence of
dissolution is apparent on the calcareous rock surfaces of the marble in the transition zone. The
transition zone is in full hydraulic connection with the regolith, and groundwater communication
between these two zones is unrestricted. Figure 5-1 depicts the current understanding of the
transition zone surface topography. Figure 5-2 presents the estimated thickness of the transition
zone and the high transmissivity area north of Slow Creek.
Figure 5-3 depicts the current understanding of the transition zone surface topography in the
WMII-B area. The transition zone surface is lowest near the former location of the underground
concrete storage tank, and the low surface extends beneath the manufacturing building to the
south and also to the north. The transition zone surface rises nearly 70 feet to the northwest and
the southeast. In this area, the transition zone typically consists of a sequence of sap rolite- and/or
gravel -filled fractures in the upper bedrock. These fractures are well connected hydraulically with
the regolith zone.
5.1.3 Bedrock Zone Geology
The bedrock is interpreted to consist of the Murphy Marble at all locations investigated at and
near the site. The variations in rack type and mineralogy are consistent with literature
descriptions of the Murphy Marble. The dominant rock type is marble. The marble is most
frequently calcareous but is also dolomitic at some locations. The second most frequent rock type
encountered is phyllite. Phyllite is of similar composition as schist but has much smaller mineral
grains. CDM Smith believes that the phyllite is the rock type that has been described as talc;
however, a positive identification of this mineralogy has not been made. The pby] lite within the
marble usually occurs as relatively thin laminations, but thicker phyllite zones of 10-feet thick at
MW-37 and INI-C and 25-feet thick at RW-4 were encountered. The phyllite rock type typically
CDM 5-2
Smith RC RA Facility Investigation Report

Conclusions
contained weathered iron nodules believed to be hematite, and groundwater in phyllite fractures
is typically black because of the iron.
The Murphy Marble at the site was also Found to contain argillite. Argillite is essentially
metamorphosed shale, whereas marble is metamorphosed limestone. Argillite and phyllite are
not easily dissolved by circulating groundwater, and dolomitic marble is less susceptible to
dissolution than calcareous marble. As a result, the fractures in these less soluble rock types will
not be enlarged by dissolution.
The frequency of fractures in the bedrock zone is much less than for the transition zone. Fractures
in the bedrock zone, where present, are usually not filled with regolith material. However, they
may contain very fine-grained, insoluble residue from impurities in the form of phyllite and/or
argillite residue. Based on down -hole geophysical logs recorded during the RFI, the primary dip
direction of the bedrock Fractures and foliation is to the south-southeast and the secondary
direction is to the northeast.
Figure 5-4 depicts the current understanding of the fractured bedrock aquifer surface
topography. The bedrock surface is at an approximate elevation of 1,500 to 1,615 feet at the site.
A bedrock valley exists immediately north of the site in the alluvial valley. The bedrock rock
surface drops from an elevation of approximately 1,610 to approximately 1,500 Feet in the alluvial
valley at INJ-6 and MW-41. Several onsite areas were identified where troughs or depressions
exist in the bedrock surface: 1) a deep depression beneath WMU-13, 2) a trough from MW-37
down to MW-35 and the alluvial valley, 3] atrough from MW-57 and MW-39 down toward MW-
37, and 4) a possible trough from the north of the WMU-B area down to MW-22 and the alluvial
valley. Cross -sections for the WMU-B area are provided in Figures 4-19 through 4-21.
The bedrock encountered during the WMU-B investigations was typical of the site -wide
conditions and consisted primarily of marble, and phyllite to a lesser degree. Fracture zones were
encountered in bedrock in all WMU-8 bedrock borings. The upper bedrock was typically highly
fractured and weathered for a thickness of approximately 10 feet. The deeper bedrock fractures
were generally found to not be in Filled, indicating a relatively thin transition Tone.
Downstream of the site, the alluvial valley continues to the west for approximately 2,000 feet and
then turns to the south. In the area where a prominent rock ledge intersects Slow Creek to the
west, a subtle surface expression of the rock ridge protruding from the east toward a bedrock
ridge on the west side of Slow Creek is visible. The alluvial valley is narrow in this area and
appears to be restricted by bedrock. The boring log from MW-51 indicates that the bedrock is
argillite and dolomitic marble in this area, both of which are more resistant to weathering and
erosion than marble.
5.2 Hydrogeology
5.2.1 Regolith and Transition Zone Hydrogeology
A potentiometric surface map for the regolith and transition zone is shown on Figure 5-5. This
reap was created from water level measurements recorded in October 2012. The direction of
groundwater flow is to the north and northwest across the site and toward Slow Creek and the
alluvial valley. In the northwest portion of the site, the potentiometric surface is affected by
CDM 5-3
Smith RC RA Facility Investigation Report

Conclusions
groundwater pumping associated with active onsite remediation. In the areas least influenced by
the pumping, the hydraulic gradient is approximately 0.017 foot/foot.
Groundwater flow in the alluvial valley is to the west. The hydraulic gradient is lower in the
alluvial valley, 0.005 foot/foot, as indicated by the wider spacing between the potentiometric
surface contours. This is because the coarse -grained sand and gravel in the alluvial valley has a
higher hydraulic conductivity than the saprolite that exists beneath the site.
Groundwater in the alluvial valley ultimately discharges to Slow Creek. Before discharge, the
groundwater flows through the alluvium and transition zone in the downstream direction of the
alluvial valley. A perennial spring [SP-2b] has formed where the alluvial valley is restricted by
bedrock in the vicinity of the rock ridge west of the site. The presence of this spring is a result of
groundwater flow being restricted by the narrowing of the alluvial valley, which causes the
upwelling of groundwater from the alluvium.
5.2.2 Bedrock Zone Hydrogeology
A potentiometric surface map for bedrock groundwater is shown on Figure 5-6. This map was
created from water level measurements recorded in October 2012. The direction of groundwater
flow is to the north-northwest across the site and toward Slow Creek and the alluvial valley.
However, the potentiometric surface is significantly affected by groundwater pumping from RW-
5 in the northwest portion of the site,
In the alluvial valley, the groundwater flow in bedrock assumes a westerly flow direction. A
downward hydraulic gradient is present on site, where some of the regolith groundwater
recharges the bedrock. However, in the alluvial valley, the regolith and bedrock potentiometric
surfaces are approximately equal, and in some locations, the vertical gradient is reversed.
Bedrock groundwater in the alluvial valley eventually flows upward and discharges into the
alluvium. To the west of the site, the data density for plotting the bedrock potentiometric surface
is Iow and the contours are inferred. Localized groundwater flow patterns possibly exist in this
area, and the patterns may vary from the inferred flow patterns.
5.3 VOCs in Groundwater
The extent of VOCs in groundwater was evaluated throughout the investigations comprising the
RIiI, resulting in the installation of a groundwater monitoring network consisting primarily of
permanent groundwater monitoring wells. Water supply wells also helped establish the extent of
VOCs in groundwater along with the permanent monitoring wells.
Tables 5-1 and 5-2 present summary statistics for all VOCs detected from January 2008 through
November 2012 for onsite and offsite groundwater, respectively. Groundwater data from the RFI
and semi-annual groundwater monitoring events was used to generate the statistics, and the
number of detections noted includes estimated concentrations below reporting limits.
The time period of January 2008 through November 2012 was selected to include a
comprehensive data set but also one reflective of current conditions. This time period, excluding
October and November 2012 data, was also used for data calculations in the site -specific risk
assessment, which was submitted to EPA in October 2012. Additional data collected in October
CS -PM RC RA Facility Investigation Report 5-4

Conclusions
and November 2012 as part of routine groundwater monitoring and additional WMU-B
investigation activities did not reveal new or changed conditions (e.g., additional source area,
change in maximum detected concentrations, etc.). Such data are believed to have minimal ❑l- no
effect on risk assessment calculations and conclusions.
As shown in Table 5-1, 28 VOCs have been detected in groundwater on site at estimated
concentrations or higher during the RFl and semi-annual groundwater monitoring events to date.
Seven VOCs (1,1,1-TCA, 1,1-DCA, 1,1 -DC E, cis- 1,2-DCE, PCE, TCE, and trifluorotrichloroethane)
were detected at frequencies greater than 40%. In general, these VOCs were also detected at
higher concentrations than other VOCs.
For offsite groundwater (Table 5-2), 23 VOCs have been detected at estimated concentrations or
higher during the RFI and semi-annual groundwater monitoring events to date. Only three VOCs
[cis-1,2-DCE, tetra hydro furan, and TCE] were detected at frequencies greater than 40%.
Tetrahydrofuran, as well as benzene and MTBE, were detected off site but not on site, suggesting
that same compounds found at off site locations are not site -related.
Figures 5-7 and 5-8 depict the estimated extents of total VOCs in regolith and bedrock
groundwater, respectively. Total VOCs for these figures represents the sum of 1,1,1-TCA, 1,1-DCE,
PCE, and TCE. These compounds were selected for analysis because, in general, they have the
highest percentage of detections and are detected at higher concentrations than other VOCs. This
is particularly the case in WMU-B, which is believed to be the primary source of VOCs in
groundwater. Thus, these four VOCs are best representative of the site -related groundwater
plume.
As shown in the figures, the majority ofthe estimated extent of total VOCs in groun dwater above
5 µg/L is limited to properties owned by the facility. This is particularly true for shallow
groundwater (i.e., regolith). The highest concentration of total VOCs is on site near WMU-B, and
the estimated extent of total VOCs stretches to the north and northwest from this WMU.
5.4 VOCs in Surface Water
Figure 5-9 is a graphical summary of TCE and PCE in surface water samples collected during
Phase 3 of the RFI. Moving from upstream of the site to downstream, these VOCs were first
detected in Slow Creek at station CMP-3, which is located at the northwest corner of the site.
Detected concentrations were 3,9 jig/ L for TCE and 0.093 µg/L (estimated) for PCE. The highest
Slow Creek concentration of 13 jig/ L for TCE was at the next station downstream, CMP-4. Both of
these surface water stations are in the downgradient direction for VOC migration in regolith
groundwater from the site.
Downstream from CMR-4, the TCE and PCE concentrations steadily decrease. Station SW-9, which
had TCE and PCE concentrations of 1.7 µg/L and 0.29 µg/L (estimated), respectively, receives
drainage from a field; however, most of the water flowing through this stream is supplied from a
natural spring (SP-26). Similar to SW-9, SP-26 had TCE and PCE concentrations of 1.7 µg/L and
0.46 µg/L (estimated), respectively, during the February 2008 sampling event.
CDM 5-5
Smith RC RA Facility Investigation Report

Conclusions
The VOC results from stations in Messer Creek and other tributaries to Slow Creek (SW-1, SW-2,
SW-4, SW-5, SW-7, SWA and SW-11) show that Slow Creek is not receiving TCE/PCE loading
from these tributaries. Field observations during the February 2008 surface water sampling did
not indicate the presence of springs in these tributaries, with the exception of SP-26 upstream of
station SW-9. No other springs were reported in or along Slow Creek within the study area.
5.5 VOCs in Soil
The extent of VOCs remaining in soil at the site was evaluated thoroughly through M I P screening,
vertical profiling, and sampling during the additional investigations completed after Phase 3 of
the RFL In general, VOCs were not found in soil at the WMUs at levels indicative of an ongoing
source of VOCs in groundwater with the exception of at WMU-B. Vertical profiling indicated that
VOCs exist in soil at WMU-B and immediately downgradient ofWMU-B from approximately 18
feet below ground surface to bedrock. Figure 5-14 depicts the estimated extents of total VOCs
[includes all detected VOCs] by depth in soil at WMU-B. The highest concentration of VOCs
appears to exist within the 1,605- to 1,575-foot elevation range, which corresponds to a depth
range of approximately 32 feet to 62 feet.
5.6 Conceptual Hydrogeologic Model
5.6.1 VOC Source
VOCs in groundwater that migrate from the site originate primarily from the area of WMU-B.
VOCs that were released on site to the subsurface migrated vertically downward through the
vadose zone and into the regolith groundwater. WMU-A, which is immediately downgradient of
WMU-B, may also contribute low concentrations of VOCs to shallow groundwater but any VOC
contribution from WMU-A is not discernible because of the higher VOC concentrations migrating
in this direction from WMU-B. SVE systems are currently being operated atWMU-A and WMU-B
to recover VOCs from the vadose zone. The SVE systems should minimize VOC mass loading to
groundwater in the future. Source -grade VOC concentrations in groundwater are currently
limited to the area of WMU-B and are present in both regolith and bedrock groundwater.
5.6.2 Onsite VOC Migration in Groundwater
The VOCs in regolith groundwater migrate laterally to the west through the regolith and also
migrate downward and enter bedrock groundwater in the area of WMU-B. The vertical hydraulic
gradient between the regolith and bedrock in this area is downward. Downgradient of WMU-B
toward the west site boundary, the transition zone becomes thicker and plays a more significant
role in VOC migration because the transition zone has a higher transmissivity that allows
groundwater to migrate more rapidly. The highest groundwater total VOC concentrations along
the west site boundary are on the order of 1 nag/L in the regolith and transition zone and on the
order of 5 mg/L in bedrock.
VOCs are also present in groundwater along the north site boundary toward Slow Creek where
the transition zone is not well developed and a bedrock ridge exists. The highest groundwater
total VOC concentrations along the north site boundary are approximately 0.5 mg/L in the
regolith and on the order of 1 mg/L in bedrock.
cSPmith RC RA Facility Investigation Report 5-6

Conclusions
A groundwater recovery system is currently operating that consists of four recovery wells. Prior
to this groundwater recovery system, a VER system was operated at WMU-B and along Slow
Creek. While the VER system provided significant VOC mass recovery from groundwater, this
system was not effective for containing VOCs in groundwater to the site. The current
groundwater recovery system is much more effective at VOC containment and will be become
more effective in the future as the groundwater recovery rates are increased. Groundwater and
VOCs in regolith, the transition zone, and bedrock that currently migrate from WMU-B should he
recovered by the groundwater recovery system.
5.6.3 Gffsite VOC Migration in Groundwater
Prior to the operation of the current groundwater recovery system, the VOCs in regolith
groundwater on site flowed off site toward Slow Creek and migrated into the alluvium of the
alluvial valley. VOC migration in the alluvial valley primarily occurs through the coarse -grained
alluvium and the transition zone. The offsite coarse -grained alluvium and transition zone are
much more transmissive than the onsite hydrogeologic zones, and the corresponding flux of
groundwater is much higher off site than on site. As a result, the VOCs in offsite groundwater are
much lower in concentration than would be expected. This is because of the dilution that occurs
as the onsite groundwater migrates off site and mixes with groundwater in the coarse -grained
alluvium and the transition none. Following dilution, the VOC concentrations in regolith and the
transition zone are reduced by approximately 80%.
VOCs in offsite bedrock groundwater have similar migration and Fate characteristics. The VOCs in
bedrock groundwater migrate laterally on site. The primary offsite migration path for VOCs in
bedrock groundwater corresponds with the location of the bedrock trough leading off site from
MW-37 toward MW-35 (Figure 5-6). Once off site, the VOCs ultimately migrate upward into the
coarse -grained alluvium in the alluvial valley. This is because the potentiometric surface in
bedrock is slightly higher than the potentiometric surface in the alluvium, causing an upward
vertical flow gradient. As described above for the regolith and transition zone groundwater, a
high degree of dilution occurs as VOCs in offsite bedrock groundwater mix with groundwater in
the offsite coarse -grained alluvium and the transition zone.
Although not considered the primary VOC migration path, VOCs have migrated in bedrock from
the site to beneath the alluvial valley off site immediately north of the site to the location of MW-
41 (Figure 5-8). This migration direction is not consistent with the apparent groundwater flow
direction from the site. As discussed earlier in this report, inclined rock ledges interlayered with
alluvium filled fractures are believed to exist in the area north of the site in the alluvial valley.
These rock ledges likely project further downward into bedrock in the form of highly competent
rock interlayed with fractures as well. It is probable that such a fracture bounded by competent
rock extends from the vicinity of WMU-B to MW-41.
The groundwater at MW-41 in bedrock migrates upward into the alluvium and into MW-34, as
evident from the VOC concentrations at MW-34 and the vertical hydraulic gradient in this area.
Although MW-41 contains total VOCs in groundwater at over 1 mg/L, the VOCs become diluted in
the overlying coarse -grained alluvium and transition zone. This is evident from the total VOC
concentration in MW-34 of 0.1 mg/L (Figure 5-7).
CDM 5-7
Smith RC RA Facility Investigation Report

Conclusions
The VOCs in the alluvium ultimately discharge to Slow Creek. However, at any one point along
Slow Creek, a greater mass of VOCs migrate laterally than the mass that is discharged. As a result,
the extent of VOCs in the alluvium reaches a long distance downstream.
Based on the data collected during the RFl From monitoring wells and water supplies, the extent
of VOCs in regolith and in bedrock reaches approximately 3,000 feet from the site along the
migration path that follows the alluvial valley. At the end of the VOC migration path near 5P-26,
erosion -resistant bedrock restricts the alluvial valley and restricts groundwater flow. In essence,
this restriction dams the flow of groundwater, causing the potentiometric surface to rise. This rise
in the potentiometric surface is expressed as a spring (SP-26). VOCs are present in the spring but
have not been detected downgradient of this point in water supply wells. Although VOCs were
detected in Slow Creek downstream of this area, the concentrations are decreasing and additional
loading of VOCs to the creek is not indicated.
TCE migration from the site to water supply well PW-22A, which is located southwest of the site,
is not consistent with the direction aFgroundwater flow in the regolith/transition zones or
bedrock. It remains possible that an unknown source ofTCF. unrelated to the site exists within the
former capture zone of PW-22A. As concluded From the in-depth investigation of this supply well
and the surrounding supply wells, PW-22A is likely draining groundwater from shallow rock
depths into deep bedrock along the well casing annular space. A well -developed transition zone
possibly exists in this area, which is a possible reason why the casing was installed at such a deep
depth. Casing would be necessary to prevent infilling of the well by lose materials in the
transition zone. Evidence of such a transition zone was observed south of PW-22A at PW-39.
During the investigation of PW-22A, a static water level elevation of 1,608 feet was recorded.
Typical regolith groundwater elevations at WMU-B are approximately 1,617 feet and 1,616 in
bedrock. As a result, the potential exists for preferential groundwater migration in this direction,
although a preferential flow path has not been directly identified.
CDM 5-g
Smith RC RA Facility Investigation Report

Recommendations
Section b
Summary
As presented in the preceding sections, VOCs are present in groundwater off site and on site at
concentrations that exceed MCLs. Law levels of VOCs are also present in surface water off site.
Investigations on site indicate that VOCs are present in soil and groundwater near WMU-B
(former UST) at concentrations high enough to be acting as a continuing source of VOCs in
groundwater downgradient of WMU-13. Limited to no impacts were observed at other WMUs on
site.
Based on observations since the start of the RFI, the following IMs have been implemented or are
planned For implementation within the next year:
1. Residents potentially downgradient From the site have been connected to the Town of
Murphy water system and their associated supply wells have been locked out from use.
2. The groundwater extraction system has been expanded to include two new wells (one
regoIith, a n e bedrock) completed in fracture zones that combined, can pump more than
50 gpm. The associated groundwater treatment system controls have also been upgraded
to allow remote monitoring and control.
3. An SVE system has been installed and is operating in the vadose zones at WMU-A and
WMU-B to address VOCs in soil and soil gas in these areas.
4. An onsite IM consisting of thermal remediation of groundwater near WMU-B is currently
being designed,
5. An IM consisting of groundwater reinjection off site with enhanced recovery an site is
currently being designed.
The next work phase for this site according to the RCRA corrective action process is the CMS, and
a CMS work plan will be prepared to guide the study. The CMS will help identify what remedy or
remedies will be required in addition to the IMs to achieve protection of human health goals.
Determining appropriate remediation goals for use in the CMS will require a risk assessment, and
a risk assessment incorporating the RFI data was recently under a separate cover (CDM Smith,
October 2012).
CDM 6-1
Smith RCRA Facility Investigation Report

References
Section 7
References
Arcadis G&M, Inc. May 2003. Status Report and Off -Site Investigation. Prepared for Litton
Systems, Inc., Clifton Precision.
Camp Dresser & McKee Inc. August 23, 2005. RFI Work Plan Addendum: Off Site Groundwater
Characterization, Bedrock Investigation, and Vapor Intrusion Assessment. Prepared For
Northrop Grumman Guidance and Electronics Company, Inc.
Camp Dresser & McKee Inc. April 24, 2007. RFI Work Plan Addendum []-Revision #1. Prepared
for Northrop Grumman Guidance and Electronics Company, Inc.
Camp Dresser & McKee Inc. August 22, 2007. Scope of Work for "Phase 111" RFI. Prepared for
Northrop Grumman Guidance and Electronics Company, Inc.
Camp Dresser & McKee Inc. October 31, 2007. Expanded Scope of Work far Phase III RFI,
Prepared for Northrop Grumman Guidance and Electronics Company, Inc.
Camp Dresser & McKee Inc. January 18, 2008. Surtbce Wa ter Samp ling and Analysis Plat).
Prepared for Northrop Grumman Guidance and Electronics Company, Inc.
Camp Dresser & McKee Inc. April 2009.Onsite Source Screening Investigation Technical
Memorandum. Prepared for Northrop Grumman Guidance and Electronics Company, Inc.
Camp Dresser & McKee Inc. July 2010. Resource Conservation and Recovery Act Facility
Investigation Report. Prepared for Northrop Grumman Guidance and Electronics Company,
Inc. Superseded by this report.
Camp Dresser & McKee Inc. March 2011, West Groundwater Flow Evaluation Technical
Memorandum. Prepared for Northrop Grumman Guidance and Electronics Company, Inc.
CDM Smith Inc. March 2012. Waste Management Unit BStep-Out Investigation Technical
Memorandum. Prepared for Northrop Grumman Guidance and Electronics Company, Inc.
CDM Smith Inc. March 2012. Offsite Investigation r/ Injection Well Instollation Technical
Memorandum. Prepared far Northrop Grumman Guidance and Electronics Company, Inc.
CDM Smith Inc. October 2012. Risk Assesson en t Update Report. Prepared for Northrop
Grumman Guidance and Electronics Company, Inc.
Stearns, Conrad, and Schmidt Consulting Engineers, Inc. October 1990. Phase I RCRA Facility
Investigation Report. Prepared for Clifton Precision.
Stearns, Conrad, and Schmidt Consulting Engineers, Inc. September 1991. P17ose 11 RCRA
Facility Investigation Report. Prepared for Clifton Precision.
CDM 7.1
Smith RCRA Facility Investigation Report

References
U.S. Environmental Protection Agency, November 1986, SWB46 - "Test Methods far Evaluating
Solid Waste, Physical/Chemical Methods. " Thi rd Edition (and updates).
U.S. Environmental Protection Agency Region IV. April 27, 1988. Administrative Order on
Consent. Issued to Litton Systems, Inc.
U.S. Environmental Protection Agency Region IV, Science and Ecosystem Support Division.
Athens, Georgia. November 2001. Environmental Investigations Standard ❑perating
Procedures and Quality Assurance Manual.
U.S. Environmental Protection Agency Region IV, Science and Ecosystem Support Division.
Athens, Georgia. November 2007. Field Branches Quality System and Technical Procedures.
U.S. Environmental Protection Agency. May 2012. Regional Screening Levels for- Chemical
Contaminants at Superfund Sites.
CDM
Smith RCRA Facility Investigation Report �-

Figures
smith

J
- Form r Clifton C i8o0
Precision Site 7 8
- 1
0
PEACH E CREEK
ti� 'sso NC 141
1 700 I
Topographic Contour Interval = 59 Feet
National Geodetic Vertical Datum 1929
1" = 1,800'
900 Feet 0 1,800 Feet
Town of Murphy
Former Clifton
mm Prescision Site
Smith
N
W E
5
Figure 1-1
Site Location Map
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

N
W
E
5
0
WMU-E: Treatment Area '
& Filtration Pit
WMU-F: Chemical
Treatment Building
IF z
4 Slow Creek
i#
Fili'J •4 r i:; MW-22
= Z F M1N 3I` WMU-D:
m WMU-A: Dru$ • &^ ;I`;''' Drainfield
•� MW-14R
Storage Area
MU-H: Machine
olishing Pond Shop - -
Former Sanitaty or WMU-C: Undergrou
Wastewater Crushed Tanks
MW-6 RW-1S
Treatment System Nw-5lll� RWjD
WMU-G:
Percolation Pit WMU-B:
Underground
Storage Tan
Main r t
Facility Plant
r # Boundary 11IN1111111111061
Scale in FSet _ �" Map Data Source; c
2008 Aerial Photograph, Cherokee County,
$0 10
NC, Mapping/GiS Department-
9F8 M- 0
MW-19R
P1W-19 ltii! 261
4 1
EWaste Management Unit (WMU) Figure 1-2: Waste Management
Bedrock Zone Regolith Zone
Unit Location Map
EE)Recoveryweii ®RecoveryWell _ Wells Existing Prior RCRA Facility Investigation
DM *Monitor Well +Monitor Well _ to Current RFI Former Clifton Precision Site
SmiMurphy, North Carolina

4 A PW-44 7 r
s �z Messer
lip
I'Creek r .PW-5S' 'r^
PAN-6A ^
PW-1 PW-5
.f A
+ ; J '
41
IL
41
r e► ■ y r r -' r r
PW,12 PL
A SW-2
��-4;jr 4' f!!!!Ill - - "
-� ' MW-51 `' RCMP-2 MW-50 1 �. .
j � MW-40 ■
. �. P.W/-99. W 3 CMP, CMP-3
+ t , S �. �' ' 7 SW-4. , -S�` r....r s S-3 MW-36 - iT, r
� t 1� r ■ SW-5 • .rr r +T.t4 . �i t1 ■ , yr'_ •r _ y
• - " �� �� W-� sw-s MW-37 rme Clifton �. ; F e * �.
• ". 11 w P%v-18S r Precir?n. 5ite�
3 t PW
* .r ti , i PW-15 e 1P i7 M1�1 38 ti - �.. �i* * i
Grp !�- �S�W■-9 slaw Creek R . ' O ���,%%% (>PW-18A #
�1W-3-39: i 16
,, ,� PW-49.So
r� y
3 t i ?� PW33] P�W--22A M"1�45 ,. ♦ � t `" t.
f Menlo
.. + �PVIi-zsa "• Lane lY Pw-2zc0 Facility w-$ ., +t ♦ W
' "
t
� " Pw-q Bounds�. Pl+lf 59 PV�f-60` ,s
Pw-10o iA _
• � PW-34 -� r'�• ..l
+ �. ,O.l _� :�. I'�1 Pw-63 --
r PIN-3 I 1. PW-540 Q,- i
{- PW-65
�d sW 10 , ... ��W-366 RW-386 ` + I PW-67 } '�
'• 336 PW-3 A p -370 OPW 3SA -. s
PW-33
P -79 f � ' PW-68/69
y
► P • r ' ; �,� ,; Greenlawn Cemete PW-95A/S
�"Y Road ,.
. •'�-:•� 1y" L Y . •'3W4W
■ PW-85 ` r .s" . • R.;
a
Map Data Source:
2008 Aerial Photograph, Cherokee County,
NC, Mapping/GIS Department.
Smith
O Inactive Water Supply
(PIN - Well)
Active Water Supply
(PW - Well, SP- Spring)
! r.. i PW-93
Regolith Monitoring Well A Creek Monitoring Point
Bedrock Monitoring Well ❑ RCRA Facility Investigation
0 Exploratory Boring Surface Water Station
PW-78
Scale in Feet
200 0 400
Figure 1-3: RFI Phases 1 - 3
Investigation Location Map
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

IF
I
WMU-E: Treatment Area & Filtration Pit MIP-17
WMU: Chemical Treatment Building 1 WMU-D:
• MIP-270 MIP-1$ MIP-ig ' Draiinfield
'i•'�"• MIP-20
WMU-A: Drum I 18� MIP-16C r
torn e Area MIP-290
SS-04MIp-I 0 MIP 31
MIP-46 MIP 21
MIP-24 © 5B-QSMIP_z MIP-30 !�� 0 6IP-33
WMU-H ; MIP J6 0 SB-07 SB-18
MIP-25 IP-3 MIP 32
Polishing Pond SB 05 iMIP fi F MIP-34
MIP-26 �..
Former Sanitaiy 0 S6-100 IP-45 WMU-C. Un-
dergrounl
Wastewater MIP-23 MIIPP-7 Crushed Tanks
MIP 5 MIP-8
y MI-16 B 01 SB_09 46MIP-9
Treatment S stem 56-11
SB 16 MIP-4 5B MW0r s ;. MIP-12
WMU-G: 5B-08 + ;�si3
A Percolation Pit M P-6 0 15
56 03 SB-14 IMIP-14 ",
• SR-1� ,.,..I I r.
4
h)P-36t__ n
MIP-37 '
SB-19
MIP-380
- MYe
MIP-400
+ Scale in Feet
1
r
It
'11
17
MIP-41 NIP0
--49
,6B-22
I
MIP-42 I.5U 0
5B-20
r
AY
ft-.r
AL %
MIP-1 Membrane Interface Probe (MIP)
0 Test Location
CDM Waste Management Unit (WMU)
Smith Soil Confirmation Sampling Location
1k
11
ki
Figure 1-4: Onsite Source
Screening Investigation Locations
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

r
N
75 37.5 0
W E
S
1 l 1 .
i
WMU-A
Drum Storage Area
MWU-B
Underground Storage Tank
WMU-C
Underground Crushed Tanks
WMU-D F
Drainfield
WMU-E "
Treatment Area and Filtration Pit
WMU-F
Chemical Treatment Building
WMU-G
Percolation Pit
WMU-H
Polishing Pond
Map Data Source:
2008 Aerial Photograph,
Cherokee County, INC.
Mapping/GIS Department
Smith
75 Feet
I a
k
0 Boring Location with Soil Boring Number
® Waste Management Unit (WMU)
T
4
wMu,E+F
7 6
L
2 WMUu C 3
r
1 �
4
2 WMu-C
3
7 1 4
6
5
r
r
WMU B
Figure 1-5
Additional Soil Assessment Boring Locations
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

EN } - 't"_
W +AM
E
a
S
y rAL
f 1
2 100 0 1 200 Feet '.I''
01
rD
Ik
Map Data Source:
2008Aerial Photograph,
Cherokee County, NC
MappinglGIS Department
Smith
7 Boring Location with Soil Boring Number
n
r;
,I
Figure 1-6
Additional Soil Assessment Background Locations
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

i
- r k
If
Nt
O '
T o 1
4
a � �
a � ;
i
� t
• ' �1 i 1640
,r }. • -
Ir
, N ; '
OWest Groundwater Flow Investigation Wells
$ Regolith Monitoring Well
E Bedrock Monitoring Well 1624
Q Reg oI th Supply Well
i w •
• Bedrock Supply Well
® Regolith Fxtractlon Well — _
® Bedrock Extraction Well `*
Aerial Image: 2M Cherokee Co, NC Orthoimagery, Cherokee county, K GIS aepalment.
Surface Waler. dwq—dassific &ns_2W?1130. INC DENR Division of Water Ouaiity - Primary Surface Wafer Classftaliws"
Topography: Cherokee County - Elevalion Grid, NCDOT GIS &arch, May. 20W.
Topographic Contours
Scale in Feet - - - - - - - - - Site Boundary North American Vertical Datum 1988
Smith Parcel Boundary —2000-10-Foot Interval
0 400 800 Streams
Figure 1-7: West Groundwater
Flow Evaluation Locations
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

HP-32
9
HPBB-8 HP-24
46
GW-7B
• . ii H P-31 G W-7+
H P-23
HPBB-9 HPBB-1 0 HP-14
/1HP-30 4
HPBB-11
I
HPBB-2 I
HPBB-3
HPBB-12
HPBB-4 1
GW-8 HP-20.
GW-$B
0-HP-15 HP-16
GW-4 H P-24 0
# MW-6 MW-4
HP-18
_ HP-7
GW-3s/d Hi 2$ F
HP-17
0
HP-8 GW-2sld HP-19
HP-13
s
HP-10 HP-rfi - GW-1 B
-1 B
HP-9 W-1d HP-5 GW-5B
HP-11
GW-, s7d RW_ 5 GW-5D
�+ �� S.
1� � H P-12
HP-4 r HP-1
4P-26
H P-�
HPBH-5 1
f1 HPBB-6
HPBB-7
IS Vertical Hydropunch Boring +Vertical Bedrock Monitoring Well Phase I Boring/Monitoring Well
CDN ■ Angle Hydropunch Boring Angie Regolith Monitoring Well Recovery Well
Smith + Vertical Regolith Monitoring Well + Angle Bedrock Monitoring Well Existing Monitoring Well
N
W E -�----
S
0 35 70
Scale In Feet
Note:
1. Recovery well RW-1d is not an active
recovery well and is currently being
used as a monitoring well.
P H P-21
� HP-27
GW-61D GW-6B
HP-22 GW-6S
•' •.■
Figure 1-8: WMU-B Investigation Locations
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

,--7 r . ►
Facility -Owned
Parcel Lines properties
40
Former Clifton 0
Precision Site k ell Legend
dw
(DRegolith Extraction Well
Transition Monitoring Well
` r Regolith/Transition Monitoring Well
r
(DRegolithlTransition Extraction Well
• r ❑Bedrock Monitoring Well
r -*Regolith/Transition Reinjection Well
Scale in Feet ' (DBedrock Extraction Well
200 4d0 Bedrock Injection Well
Figure 1-9: Offsite Groundwater Investigation Locations
RCRA Facility Investigation
CDM Former Clifton Precision Site
Smith Murphy, North Carolina

I
I 1
I
I
7�j
I
4I
10
Nn
+ N16
N13 N14
- + S11 r:
nvxf510 . Sia 5f3 * 5 ♦S14 ♦ S1� 516-
* I _— - -
'N8 N N + - Il •. Nx Ei Jill
: +S2-
-4 Sg ♦ 5 ♦53 _
_ N18 +58 + S7 t SG,
a i t 'N1 j 1
Nat; Nav t
+ Naa
; ♦ • ' r +3 +4
I
Sax 520 N19 '►
N25 rk
I
+ + 518+S1�+ -
N
CDM+ Transeet Station Scale in Feet
Smith �ransect ....
0 zgo 500
Figure 1-10
Geophysical Survey
Transect Locations
RCRA Facility Investigation
Farmer Clifton Precision Site
Murphy, North Carolina

Messer■■�■■'�IR�I■■■■■■'
r Cree rr�.'L;E�■■�■��■.
� ►fit Y� �■■iLti
w c"!W oil Q■■9
d r -
�Ili■■iil�■�3■■
Is
ndrix._ :■! ONE
■ ■■■■■■■■■■ law Creek
- �... .. I ■■■ism
-
i;40
• • Plit ffjL
Former OWC
recision Sit
Dw Creek
nlawn Cemetery Read
•t
Map Data Source: County Rural/Residential Church/Religous
2008 Aerial Photograph, Cherokee County,
NC, Mapping/GIS Department.
Multi -Residential Cemetery Figure 2-1: Land Use Map
CDW1 Scale in Feet
1 � School �� Commercial/Industrial RCRA Facility Investigation
■
Former Clifton Precision Site
Smith 300 0 600 Land use designations are based on CDM Smith observation during the RFI. Murphy, North Carolina

a Via' Messer ;
Creek
�62a
H ndricks oad *'
Slow Creek•
`n r acility _
•+ �r 'Boundary
Runoff �`
ti
Slow Creek
• 'R r Memory Enclosed Op
lane Depression Drainage Swale
mk
11600 ? Green T
lawn Cemete
. ry Road
W �o
Data Sources: Scale in Feet
Aerial Photography, 2008, Cherokee County Mapping/ GIS Department. Elevation Contour Figure Z-Z
Topography, 2007 LiDAR Grid, North Carolina Department of Transportation GIS Unit. Interval = 20 Feet 200 0 400 Topograhic Map
North American Vertical Datum, 1988 RCRA Facility Investigation
CDM 1620 Dashed line on site with arrows designates a Former Clifton Precision Site
Smith runoff divide and associated directions of drainage. Murphy, North Carolina

/ ti A.J I � Zah _
N trg x�fis'5Y' Zch I 7 f y-.3 zd Z
f �C i2 .�~ ` Gail: j�..r`• 1 6❑ '�
ZIA/
Zwe .0 1 r !sa fr
82
�4
d8 7a 6+
TAN EE_� ,.- - ��.- J6 , i �,- � ; _ ,•
ff � y zrna
1' 1 f1 J (]
73. .TG } � •..1, 20 - � I 8Q
r / Cat LINI1 J..
O f. J(I �f 71.f� _J.'t66 ! 5q r� f tl 17 Beth J3 J s]
2—f f , 2 ZweJ CCC an
�pQ f r 14
Zd
20
~',
dJ 7 75 , r" 1 /S 7NI V . _ /• ' 30�
z
s 1
25
_ [
r
S fit
id r �r5. '3 a nt `�1 i.2: ! fki •..`x�.ru znt.. L �. f f i f '�� -_
Zina._
�{ Pzd Peachtree
Co n
35' n rr�ty,�
75 �t rn• 1 r �" �� :�
m hq } Zone— .r �]►Qd �- - - -
40
ZMb
Zb i71i: +$ Zone 7-ai, _ n l.. '_�� •..�..
r8 5
rr -, f- yyi zgS
Zd
�h ' ° {{ NORTH CAROL
_ �..
68`J : r EYAr.
Zme_ O R
f Zw c
zh Z.na ZwB zalli ZYbn
Geologic Map of Southwestern North Carolina Scale in Miles Thrust Fault Figure 2-3
Including Adjoining Southeastern Tennessee Vertical Beds
and Northern Georgia. Weiner& Herschel, 1992. (lower plate) -A- Regional Geologic Map
d 5 10 15 (upper plate)
Inclined Beds RCRA Facility Investigation
CDM Boundary of -�Former Clifton Precision Site
Smith Map unit descriptions are provided in Table 2-1, _ Murphy Marble Belt' (dip angle in degrees) Murphy, North Carolina

I
T-18
3/15/06
pth =
31 feet
Y+CE
c1
PCE
<1
1,2-DCE
<1
1,1-DCE
<1
1,1-DCA
r1
)PT-12 3/13/0
)epth = 67.4 fee
'CE 3.1
ICE ¢1
.,2-DCE <1
.,1-DCE c1
i -nrA � y
❑PT-20
3/15/06
Depth =
57.5 feet
TCE
<1
PCE
[1
1,2-DCE
<1
1, -DCE
<1
1, -DCA
<1
DPT-21
3/15/06
Depth =
34 feet
TCE
8
PCE
0.243
1,2-DCE
1.9
1,1-DCE
0,643
1,1-DCA
0.39 ]
Data Source:
�al Photograph, Cherokee County,'
rfiL(KS Department.
DPT-16
3/14/06
Depth =
1S feet
TCE
[1
PCE
ri
1,2-DCE
<1
1,1-DCE
c1
1,1-DCA
C1
q
DPT-14
3/14/06
Depth =
35.7 feet
TCE
C1
CE
<1
,2-DCE
r1
1,1-DCE
i <1
1,1-DCA
C1
OPT-17- 3/15/06
Depth = 116 feed
TCE <1
PCE -Ciwft
1,2-DCE C1
1,1-DCE ¢1
1,1-DCA C1
DPT-19 3/15/06
Depth = 59 feet :
TCE 160
PCE 2.8 :
i -nra i"Jn
do
ado
w� At
4 too
r,

i r e .r r r r i r r. i t PW-44 r
i N600 Feet Nort
z PW-68
r PW-1 *Ar� r
Su ey Boundary 1Fly V
r/
' PW-s
r
' r
i ■ , PW-8 PW-9 r
Survey Boundary #3}
40
k ' _ f} ►
PW-9 �► i
+►l '
7 � -
[ ,. PW-15 IOQW-17
• Pw Survey Boundary #1' Q Pw-i8a -
-?' PW-16 w I - �► r
r r -- f �. ► AA
Survey Boundar2 r
t ' PVJ-22B � ' � `,' t ri r PW-101
� � � ' � •= RW-: :. , +► PW- PW-56( r --2,500 Feet East of
Survey 8ounciary #3
s' fPW-)8A P 1 ' — _ — _ — - PIN-2— ♦ — - - _ — — i► 5$ PW-Gl� P�IIf-62 h
PW-60 J.
�W-i00 �^ f ♦ ♦ PW-ZSB � PW-34 ♦'` W-59 PW-32 PW-38B#%W-23,
PW-3 PW-S3 r
_ - ` ♦ OPW-36B r .:+� ♦ PW-64 1
P W-65
+ ► S ey - P -38A' PW-67 I
► o ndary #7 ■ <�> PW_33� _ w PW-36A - 3 ♦ s '�
W-33A ''
PW-79 + PVf1-3 PW-68/69 PW-95B
Survey Boundary #3 ►+ w s9 - . � .' '`
.� ► - ••
-80
! PW-82 PW-102 & 103
—100 Feet South-
i
C
0

MIP-279
'
MIP-28
S0
O
MIP-
MIP-16ts
MIP-29 MIP-30
® sB-1s
r
B' [Vl lr-L 1
SB-4
r
1
MIP-24 MIP-460
�
SB-7
©MIP-32
A' MIP-3
-1 WMl1-A
I
0
MIP-33 -
MIP-47
MIP-6
! S B-5
5B-i0
MIP-26
i
MIP-239
r
MIP-5
P-45
MIP-22 5B
IP-4 SB-9
.
SB-16
5B-8
MIP-7
MIP-8
MIP-9
SB-11
r MIP-11
B-2
MIP-10
SB-12
0
MIP-12
Scale in Feet
SB-13
MIP-48
-�
35 0 70
SB-21
S13-3
MIP-13
A
B
Map Data Source:
SB-14
-15
2008 Aerial Photograph,
MIP-14
Cherokee County, +
INC, Mapping/GI5 Department.
S6-15
Smith
MIP-1 Membrane Interface Probe (MIP)
Test Location
SB-1 Soil Boring (SB) Location
Cross -Section Figure 4-3: MIP Cross -Section Locations
B B RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

ECD response A
in electrovolts (eV)
1.4E+007 eV
1.0E+007 eV
=0:91III11 n-TI
1.6E+006 eV
0II9111I1AR- TJ
1.8E+005 eV
3
SB-15
5B-21
X 571000 520 g00�' I670.800
Easting survey coordinate in feet
Pasted values are total volatile organic compounds
in micrograms/kilogram from confirmation soil borings.
Cross-section provided by Vironex, Inc.
Smith
J P06 P0403
�55
17
t , SB-5
SB-9
SB-10 SB-8
A I
,Z
11630
11620
116109
a�
E
ua
1,6g0
520.700 520,600
Approximate Water
Table Surface
- - - - - Figure 4-4: Electron Capture
Detector Cross -Section A -A'
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

PIS response A A
in electrovolts (eV)
1.4E+007 eV
1.0E+007 eV
0110Iil41 M-h
1.0E+006 eV
3.0E+005 eV
I.0E+005 eV
Easting survey coordinate in feet
3.0E+004 eV
2.2E+004 eV
Cross-section provided by Vironex, Inc.
Smith
Approximate Water
Table Surface
.630
,620 0
0
z
1610
w
E
1590
Figure 4-5: Photoionization
Detector Cross -Section A -A'
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

FIB response
A A'
in electrovolts (eV)
AI: alloll M- A
3.0E+007 eV
1.0E+007 ell
3.0E+005 ell
3.0E+005 eV
1.0E+005 eV
2.0E+004 eV
Easting survey coordinate in feet
Cross-section provided by Vironex, Inc.
Approximate Water
Table Surface
,630
620 M
z
sA
610 0
w
Figure 4-6: Flame Ionization
Detector Cross -Section A -A'
�+ RCRA Facility Investigation
`iDM Former Clifton Precision Site
Smith Murphy, North Carolina

EC❑ response
in electrovolts (eV)
1-4E+007 eV
,1.0E+007 eV
3-0E+006 eV
—1.0 E+006 eV
3.0E+005 eV
1.7E+005 eV
Approximate Water
Table Surface
1,630
1,620
G
1,610
z
c
0
1, 600
`w
1,590
1,580
Posted values are total volatile organic 526,400 526,4�
compounds in micrograms/kilogram Easting survey coordinate in feet
from confirmation soil borings. Cross-section provided by Vironex, Inc.
Smith
IP07
B 11
i
] 526.600 Y
Figure 4-7: Electron Capture
Detector Cross -Section B-6'
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

PIA
PID response
in electrovolts (eV)
1.4E+007 eV
1.0E+007 eV
1.0E+006 eV
3.0E+005 eV
01:12IiI8�Tj
3.2E+004 eV
Approximate Water
Table Surface
Smith
IN
1,630
1.620
1,590
1
526,4 Q 526.4
Easting survey coordinate in feet
Cross-section provided by Vironex, Inc.
5 21:.550 526,600 Y
Figure 4-8: Photoionization
Detector Cross -Section B-B'
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

FID response
in electrovolts (eV)
9.1 E+007 eV
1,630
3.0E+007 eV
1.0E+007 eV
1,620
{141=111IY-►1
nl
1,0E+006 eV 1,810
z
3.0E+005 eV a
m
1, 600
w
1.0E+005 eV
.OEf004 eV
.OE+004 eV 1,590
Approximate Water 1,580
Table Surface
Easting survey coordinate in feet
Cross-section provided by Vironex, Inc.
Smith
Figure 4-9: Flame Ionization
Detector Cross -Section B-6'
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

N '
r
,
r
W E
r
r�
r . ... • • •. •..... •..•
r r r r
Scale in Feet r = r r
r e r r
0 250 S00 ; MW-24
MW-33 : 1610.56
_.
1610.2
Q�
+ �p 1606 ■
r a�--
•i
Slow Creek r NO% ■ f y
- RW-3
MW-42 ..r•••••" ..�' : MW-14 1597.97
1605.13 — ...... ± r 1609.02 `" a
A.-:w""-•�" r 1609.44; - • . �.. W-1 rt6���
+a �' ' ± • •' + 1607.88 N6pa
_ + 1610.63 �p�p
� r
MW-8 MW-4
r tl9 1610.0 1615.25
• RW-4
+ A614 1603.55 i '*
r ,
' MW-27
• !tea .....................• 1616.63
• Former Clifton
+ Precision Site
MW-16 s
1620.58 �M*26
• 16i7.96 •
r `� ■ i.r.sw.r
1616.23 r ................... ...: r
r ,■ , •■
r ceoe ■ a a
} ,i� f i............� ■
a
•Greenlawn • ' ;
• ,
• cemerery .. , _ • y
.......,Road
•••............
.
¢ Regolith Monitoring Well •'
Regolith Extraction Well
gure
- • - - - • - • - Site Boundary —1610-2-1-oot Interval potentiometric Surface Map
' • • • • • •
• Parcel Boundary Potentiometric Surface Contours RCRA Facility Investigation
DM Streams 11 October 2010 Former Clifton Precision Site
SmiNational Geodetic Vertical Datum 1929 Murphy, North Carolina

N '
r
!
r
W E
r
r"
Scale in Feet
0 250
- MW-25 = 6 -
i 1611.03rsy�
- MW-40 _
1608.02 A6d� 1 - +� •
1518.46
Slow Creek MN»M„ ..�...•• � � .`�.�s�,`•.t�}-t-i a
~r 1603.4
• • MW.14R
.� 1608.15
' MW-37 MW-6
1607.94 a 1610 1612.85
■
r
i PW-18A
MW-38
PW-16 No
1603.35 + Measure ent : 1609.54
• ti ! ! W-39 400
! 1612.31
• •• PW-2213
1604.59 „ „ .......................
i Former Clifton
PW-22A ; Precision Site
1607.96 i
• MW-45 1618
1608 .
fi19 39
MW-19 i
r f 1617.06 f
• 16101612 •
• .. PW-23
ir
1618.66
lip !• PW-39
1618.4
1614 • ' "' ■
.Greenlawn • V
�e'•.,• ;
MW-55
1615.$ •�......i...........
'
• .. , Road .......
a
•
-a
91E Bedrock Monita* Well • "'
Bedrock Supply Well
® Bedrock Extraction Well
Fioure 4-11: Bedrock
- - one aounaary — -,dwr - iv -root imervai
• . • ... • • Parcel Boundary 510 2-Foot Interval Potentiometric Surface Map
CDMStreams Potentiometric Surface Contours RCRA Facility Investigation
Smith 11 October 2010 Former Clifton Precision Site
National Geodetic Vertical datum 1929 Murphy, North Carolina

1 •
1
0 --
PW-16 •
1 �
-- Pumping5tart/Stop j
-10 1
■ Flaw Rate
r I
� 1
-20 1
1
I
I
-30 y
I
1
I
-40
-100 -50 0
0.02
0.01
0
d -0.01
-0.02
MW-37
0 03
1
1
I
1
50
I1^
M W-38
1 S
1
4.5
1
M ■ ■ r ■ 1 4
1 3.5
1 3
L
1 �
2.5
1 �
1
1 2
1 �
1.5
1
1 1
1
�! 0.5
100 150 200 250 300 350 400
Minutes
I
I
MW-39 I MW-43
MW-45 { -- Pump ing5tart/Stop
-0.04
-100 -50
Smith
0 50
100 150 200 250 300 350 400
Minutes
Figure 4-12:
PIN-16 Aquifer Performance Test Hydrograph
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

0 PW-22A
1-
7
1
1
----Pumping 5tart/5top_�
6
10
-- --
1
!
m
■ Flow Rate
1
1
-20
1
I
-ry25{
- —
-� -
1—
4
1
I
L
Q: -3❑
i
1
Q.
iy
N
-40
I
I
-
-45
1
1
-50
-55
-�
- - -�
■---
1
1
• 1
-60
-65
0
-100 -50
0
50 100
150 200
250 300
350 400
Minutes
0.04
—
0.25
1
1
1
I
1
I
1
1
02
0.02
1
1
-
1
1
1
1
1
1
0.15
0
�
1
MW-16
I
U
0.1
1
-0.02 r�.MW 17
1
—
MW-39
VVQ
0.05
1
-0.04 M W -45
1 +.
1;
----PumpingStart/Stop
0
1
PW-23 (right axis)
1
-0.06
.._
-0.05
-100 -5o
0
50 100
150 200
2SO 300
350 400
Minutes
CDM
Smith
Figure 4-13:
PW-22A Aquifer Performance Test Hydrograph
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

10
PW -23
5 -
-- -Pumping Start/.Stop
0
• Flow Rate
-5
m
-10 -
-15
-20
-25
-200 -100
0.04
0.02
0
d -0.02
m
-0.04
-0.06
-0.08
-0.1
-200
Smith
1
0 100 200
Minutes
300
WAX
7
6
5 Y
c
4 2
a
a
3 =
0
m
Z C7
1
. 0
500
-100 0 100 200 300 400 500
Minutes
Fioure 4-
PW-23 Aquifer Performance Test Hydrograph
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

1 1 • 12
PW-39 j • 11
0.5 t • 1 10
----Pumping Start/Stop • • • • * 9
0 - - - — — •— 8
• Flow Rate • 7 g
-ta.5
1 6 a
1 5
1 I o
-1 ! 4 ro
1 3 t7
1
2
I 1
1 1
-2 0
-100 -50 0 50 100 150 200 250 300 350 400
Minutes
0.02 -------- — 1 1.4
1 I
1 1
0.01 1.2
1 1
0 Oki
1 - 1
-0.01 — — 0.8
1 1
}, M W-16 1 1
-0.02 MW-17 0.6
1 1
-0.03 _MW-39 1 _ — 0.4
1
M W-45 1
-0-04 -p '-22A 0.2.
Pumping -Q OS 1 I 0
PW-23 (right axis) 1
1 I
-0.05 - -- -0.2
-100 -50 0 50 100 150 200 250 300 350 400
Minutes
Smith
Figure 4-15:
PW-39 Aquifer Performance Test Hydragraph
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

AA
WSW
PW-39
VITA
PW-22B
W
Smith
11
61
5 Z)at
f��WI
ENE x Fracture Plane
E 0 "Bedding" Plane (foliation)"
* "Soft" Zone (rock layering)
* Fracture Plane
E o "Bedding" Plane (foliation)"
o "Soft" Zone (rock layering)
ESE
* Fracture Plane
E 0 "Bedding" Plane (foliation)"
o "Soft" Zone (rock layering)
Figure 4-16A:
Acoustic Televiewer Fracture Plots
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

MW-45
N
��� ��NE
WNW 5D—
.6
7Q X Fracture Plane
W , E ❑ "Bedding" Plane (foliation)"
f Q "Soft" Zone (rock layering)
SW
S SSE
S-3
N
-a NNE
�o-
3° -NE
4 >
e
J6
x Fracture Plane
W E
o "Bedding" Plane (foliation)"
O "Soft" Zone (rock layering)
r �(
WSW
r
S
Figure 4-168:
Acoustic Televiewer Fracture Plots
�+ RCRA Facility Investigation
■+DM Former Clifton Precision Site
Smith Murphy, North Carolina

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Girt
ww
w ����i
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No������������■■■■�������■
of
SEEN
s�wwiwwiwwwwwww=wwwwi=wwwwwwwwwwwwwww=wwwwwwwi�
■■W■■■■ ■■■■■■■■110■■■■■
C = C =
=
7
w
w w
wail
i
iiiiwi
iiiiiii
wwiww
i
w=w
iiii'--Ai�iiii
wwiwi
wiiwwiwwiww
iiiiiiiiiiii
wwwwiw
wwww�
Aug-07 Aug-08 Au -a9 Au -1a Au 1
1,1,1-TC4 91.1.-DCA f 1,1-DCE • 1.2-DCE VAcetone • Freon 113 MEK ■ MTBE PCE IT E
Closed circles indicate detections
Open circles indicate that the compound was not detected (reporting limit posted)
Smith
Figure 4-17B:
VOC Time Trends
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

HPBB-8
A
HPBB-9
416
*—F
Oc—
714
`
S =
0 35 70
Scale In Feet
GW-8
HP-20
GW-8B
HP-15 HP-16
H P-32
GW-4 HP-25
*
HP-17 ------
M W-6
----------- -
•
MW-5
-
--*
-
HP-24
HP-28
HP-7 -HP-18
GW 3sld
M W 4
HP-13
A'
GW-7B
HP-8
G W-2sld
HP-31
HP-19
•
4
HP-10 HP-
GW-1 B
°
Ad HP-2
GW-5B
H P-9
* HP-5
HP-23
GW-7
•'
HP-11
GW-1 s/d '•
GW-5o
HPBB-1
HP-14
JAW-1s
i
--�
HP.A
, - HP-1 -HP-12
HPBB-2
HP-29 HP-2
HP-3
H P-30
HP-21
..A H P-27
B'
HPBB-6
HPBB-5---0 Note:
QR
1. Recovery well RW-1d is not an active recovery well
HPBB-3 and is currently used as a monitoring well.
HPBB-12 HPBB GW-6B
?, HP-22 GW-6©
�—HPBB-7 C' GW-65
S Vertical Hydropunch Boring + Vertical Bedrock Monitoring Well Phase I Boring/Monitoring Well Figure 4-18: WMU-Bi Cross -Section Locations
CDNI ■ Angie Hydropunch Boring Angle Regolith Monitoring Well Recovery Well RCRA Facility Investigation
Smith + Vertical Regolith Monitoring Well + Angle Bedrock Monitoring Well Existing Monitoring Well B Cross Section Location Former Clifton Precision Site
Murphy, North Carolina

1640
1630
1620
1610
1600
U_
a 1590
m
w 1580
1570
1560
1550
1540
1530
Saprolite
Partially Weathered Rock
HP42
Asph,ilt
GW-4 -4 GW-8 GW-8b E -M
HP-18
Estimated Water
Table Elevation
2,998
34,250 554
3,523
l,II'I-
--- - - - - --
162
Partially Weathered
�. Rock y.
�IIIU% I■11�IT--T--T--T-1 I111'I1V �IIIIII I,file/,'�IIIII'I. I �IIIIII% 1� 'rII111%!/.I CIIIIII%r l �I�lllr! I III I�/.1�'� I
0 20 40 60 80 100 120 140 160 180
A (West) NQIF&. Section A - A'
Units - micrograms per liter (parts per billion) Horizontal Distance (Feet)
Posted values are total volatile organic compounds (excluding trihalomethanes) in groundwater
Posted values are from 2011 site investigations with the exception of HPBB-8
HPBB-8 was drilled and sampled in November 2012
COM Baseline groundwater sampling values highlighted in yellow at the top of the screened interval
Smith Contact boundaries are dashed where inferred
HP-19 1640
HP-13
1630
5aproli -
1620
1610
1500
as
U_
-1590
0
1580 w
1570
-1560
1550
f 1540
-1530
'ff���Ir•���I
200 220 240 260 280 300
A' (East)
Figure 4-19
WMV-B Geologic Cross -Section A -A'
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

1fi40-
1620
161
" 1600
Q
IL
c
a 1590
`w 1580
New Plant SuPldino
WNIU-8
Soil Vapor Extraction System
"Grassed 30
I
I
Lin an
HP-74 r1640
1620
1610
1600 y
LL
1590 0
4"
co
1580 w
1570
1560
1530
0 30 60 90 120 150 180 210 240 270 300 330 360 390
Section B - B'
B (West) Horizontal Distance (Feet)
B' (East)
Rotes:
Units - micrograms per liter (parts per billion)
Posted values are total volatile organic compounds (excluding tdhalomethanes) in groundwater Figure 4-20
Posted values are from 2011 site investigations with the exception of NPBB-2 and HPBB-10 WMU-B Geologic Cross -Section B-g'
NPBB-2 and NPBB-10 were drilled and sampled in October and November 2012 respectively RCRA Facility Investigation
CIDM Baseline groundwater sampling values highlighted in yellow at the top of the screened interval Former Clifton Precision Site
Smith Contact boundaries are dashed where inferred Murphy, North Carolina

i
Asphalt Grass
Estimated Water
27
CU ieoo- ,wo
LL
Sao_ - ago �
....,-1580
/„0
r: i�iiiiiri�� ed Rock Vol ���'�
01
1520 ��/�ie�� i �i�i� -1520
i�
c q�rxveea 1510
C (North) Units - micrograms per liter (parts per billion) Section C - C'
Posted values are total volatile organic compounds (excluding tfihalomethanes) in �rtr Horizontal Distance (Feet) WMU eG Figure4-31
Section C-C'
HPBB-5 was drilled and sampled in October 2012 KRA Facility Investigation
�`�� •. Geologic
Cont
act owevnaare m.�moowhere inferred yellow at rrre mawme:�.erreenerva� Murphy, North <a.oii,x

HPBB-8
2.4
46
HPBB-9
3.7
46
HPBB-10
1.04
7
HPBB-11
—N❑
Smith
1
H P-31
1.8
1
HPBB-1
3.9
46
HPBB-2
4.37
46
N
W
E
H P-20 42
0.05
1 0 3-5 70
Scale In Feet
GW-8= -
0,02 r
HP-16
a.7
HP-32
0.064 OHP-15 HP-17
HP-25 13 N❑
GW-4 0.037
0.28 HP-7
GW-3d 2.3 0.045
0.033 HP-13
HP-8 ND
101 0.002 HP-6' r7.1 GW-2d HP-19
46
HP-24 0.95 HP-28 0.0068 ND
46
13 ND � HP 2
- 8.4 HP-5
6.0 '
6 0 GW-1 d 9.4
HP-23 HP-1 0 4 5 + HP-1
6.8 _ 0.0058 ' -HP-4 29,000
46 46 -14 HP-9 0.096 HP-12
190 0-0,0031
HP-30 01 p!1 -
8.2 00 --- --_ HP-11
HP. 3 115 H P-21
250 N❑
HP-29 GW-5D NO
HP-26 --------1. TCE - Trichloroethene
57 ,� HPBB-6i
HPBB-5 0.0631 , 2. Concentrations are given in
HPBB-3—,_, 6.48
6.55 HPBB-4 milligrams per kilogram.
46 1.59 p
3. Shallow depth interval is from
NP-22 GW-61D 20 to 45 feet below ground surface.
HPBB-12 N❑ ND
0.1833 4BB-7 4. Horizontal location of angle borings
0.572
are approximate,
Vertical Hydropunch Boring • Angle Regolith Monitoring Well
■ Angle Hydropunch Boring b3- Phase I Boring/Monitoring Well
+ Vertical Regolith Monitoring Well
Figure 4-22: WMU-B Shallow Soil TCE Isoconcentration Contours
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

HP
0.088
L—j GW-8 HP-15
0.0063 3.2
HP-32 r
NO HP-25—o HP-16
do G W-4 0.027 1.0
0.0022� HP-7
HPBB-8 HP-24 1.1
0.0049 ND GW-3d
46 HP-31 46
0.025'i HP-6
NO Na _7 va $ 0.0027 GW-2d
,0.012
HP-9 H P-28 ,
ND NO 1 f � �-----
HP-23 l J GW-1d
ND i HP-10 jjj 1.1
HPBB-9 HPBB-1 HP-14
NO NO 46 NO ND--- Jl HP-59
- 1.0 C
HP-30 HP-4 CV
NO 0.026 HP-3
3.8
HPBB-2
NO HP-29
HPBB-10 NO 0.32
26
NO
46 .3
HPBB-5
HPBB- � 1
HPBB-11 ND HPBB
ND ND
HPBB-12
ND HPBB-7
0.0159
Smith
HP-17
NO
6
HP-18
4.7
HP-19 HP-13
0.0027 �ND
HP-2
3.0
412
H P-1
00
H P-12
0.014
HP-11
8.2 L
H P-27
NO
0.123
* Vertical Hydropunch Boring / Angle Regolith Monitoring Well
■ Angle Hydropunch Boring Phase I Boring/Monitoring Well
Vertical Regolith Monitoring Well
N
W E
S
0 Scale In Feet
70
H P-21
NO
Notes:
1. PCE - Tetrachloroethene
2. Concentrations are given in
milligrams per kilogram.
3. Shallow depth interval is from
GW-6D 20 to 45 feet below ground surface.
NO
4. Horizontal location of angle borings
are approximate.
Figure 4-23: WMU-B Shallow Soil PCE Isoconcentration Contours
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

3.5
a
GW-8 L�j / j
0.02 HP-15
31 ~
G W-4
ND
HPBB-8
NO 4'
H P-31
2.5
HPBB-9
0.0019
46 HPBB-1—*
NO
Smith
HP-16 '' A-..-
HP-17
HP-25 1
6.1 HP-18
GW-3❑ W15
25 HP-7 HP-19 HP-13
HP-8 90 GW-2D 12 0.033
0.17 8.8 !
+HP-6/ HP-2
f� 8.3 H P-5
r J1 13 HP-1
Z
♦HP-9 GW-1 280
240 160
HP-30 HP-4 -HP 3 d
11
HPBB-10 NDBB-2-*
NO
�HP-2s
HPBB-3
4.4 *-HPBB-4 HP 26-�&
0.88 6.7
HPBB-11
NO "HPBB-12 t'
ND
HPBB-7__j
-0.553
i
84 A 130
H P-28
HP-10 110 HP-11
2,300 99
GW-5D
HPBB-5
0.301 HPBB-6
0.0013
HP-27
0.0013-
1
HP-22 GW-6❑
NO NO
�l
• Vertical Hydropunch Boring ID Angle Regolith Monitoring Well
■ Angle Hydropunch Boring ..L, Phase I Boring/Monitoring Well
Vertical Regolith Monitoring Well
H P-21
NO
40
N
w E
S
0 3-5 70
Scale in Feet
Notes:
1. TCE - Trichloroethene
2. Concentrations are given in
milligrams per kilogram.
3. Deep depth interval is deeper than
50 feet below ground surface.
4. Horizontal location of angle borings
are approximate.
Figure 4-24: WMU-B Deep Soil TCE Isoconcentration Contours
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

0.35 0 1
In
S
0 3-5
scale in Feet
E
70
L_j G W-8 I
0 01 HP-15
0.5
HP-25 HP-16---
0.99 0.007 HP-17
ND S ND
ND
ti. HP-7 HP-18
HPBB-8 ND 0.027
0.32
ND -
.32 #
HP-31 '' GW-21) HP-19 HP-13
N❑
HP-6 0.003 N❑
HP-8 _� 0.71 1.1 p y
1 0.035 41
HP-2
HP-9 C 0.13
ND GW-1 D HP-5
BB 9 f �i f 0.0013
ND
HPBB-1 HP-30 HP-4 HP-1
ND 0.69 HP-3� —1.5
3.3 HP-28 l HP-21
+-ND ND
,�
HPBB-10 HPBB-2 HP-10 - -
HP-11 Notes:
ND ND ND • _AL 2.2 1. PCE-TetrachIoroethene
BHP-29 - HP-27
HP-26 HPBB-5 0 A --MD. 2. Concentrations are given in
0.012 0.0091 GW-5D HPBB-6 milligrams per kilogram.
HPB&3� Ali 8.4 ND
HPBB-11 ND 3. Deep depth interval is deeper than
ND 50 feet below ground surface.
HPBB-4 HPBB-7 -HP-22 GW-6D
��PDBS-12� ND 0.017 N❑ ND
�' 4. Horizontal location of angle borings
are approximate.
Smith
* Vertical Hydropunch Boring ;♦ Angle Regolith Monitoring Well
/, Angle Hydropunch Boring Phase I Boring/Monitoring Well
+ Vertical Regolith Monitoring Well
Figure 4-25: WMU-B Deep Soil PCE Isoconcentration Contours
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

T
HPBB-8
7.05
ill
HPBB-9
1.164
i
'T'•r '�,\
HPBB-10
0.023
4vNPBB-11
HP-20
0.0037
G W-8
0.12 ±_ _
HP-32 HP-25 wHP-15
0.063 GW-4D 0.14 30 HP-16
16 0.36 1.3
6 1 HP-18
77 GW-3D 0.1 ❑!�
HP-31
0,26
:la►�C?
HPBB-1 -* .,HP-30
2 ! 8.5
HPBB-2
7.8
46
H P-24
0.1
0.042
HP-17
0.15
0.014 �,_HP-7
HP-8 0.053 GW-2D HP-19 HP-13
l0.0049 0.011 0A015 0-0.0015
4 HP-2 46
0.6
HP-6 IHP-28 HP-5
0.0054 J 0.g0078 ❑ 74
rr i +1 HP-1
H P-10 1G W-1 D . 160
- 0.00017 1.7 tip
�j H P-26
rJ 0.41
Apt HP-12
�0,0037
HP-4
0.02--HP-11
HP-3 0.0882'
1
520 GW-5D'
- - 0.00063
HP-27
L 0.000 i
HPBB-5 -
1.13 HPBB-6
0.0145
i
H
S
0 35 70
Scale In feet
H P-21
0.00034
46 Notes:
1. 7CE - Trichloroethene
2. Concentrations are given in
milligrams per liter.
3. Shallow depth interval is from
20 to 45 feet below ground surface.
HPBB-7 riP-22 GW-61D
l'-0
HPBB-12 0.44 ND 0.0012 4. Horizontal location of angle borings
251
t Q are approximate.
Vertical Hydropunch Boring Angle Regoiith Monitoring Well Figure 4-26; WMU-B Shallow Groundwater TCE Isoconeentration Contours
VaN1 L Angle Hydropunch Boring aip Phase I Boring/Monitoring Well RCRA Facility Investigation
Former Clifton Precision Site
Smith + Vertical Regolith Monitoring Well Murphy, North Carolina
7

HP-20
0.0087
1
GW-8
Q.Q62� 1.9 HP-15 � r
H P-32 9
0.00066 GW-4D HP-25
ND 0.17
HP-16
2.1
0.0596 0.000 GW-3❑ HP-7
0.0596 0.Q0Q71 0.0023 0.067
H P-31
0.0019 GW-7 HP-8 HP-28 GW-2❑
1 0.1 0.00041 qND `0.014 i
H P-6 H P-2
HP-9 0.0022 r 1.2
HP-23 ND
HPBB-9 HPBB-1 0.091 0 HP-10 GW-1 D
T -0.27
0.0107 0.0069 1+ IV D
j - r HP-4
HP-30 HP-14-0.0042
jj+; DAg 0.16
ff HP-3
HPBB-2 f HP-26 7.5
0.095 .0094
H P-29 + 1`
46 0.00037
-HPBB-10 L ,1
0.00Q49
.7
HPBB-3_0
NDBB-11 ,,)- 23 * ' DBB-4 fl 53B^6
HPBB-12
- _0.0023
le Vertical Hydropunch Boring
CDM L Angle Hydropunch Boring
Smith + Vertical Regolith Monitoring Well
wHP-17
0.0019
H P-18
2.9 �HP-13
ND
W_H P-19
0.0034
`or HP-5
19
HP-1
19
0HP-12
0.Q16
HP-11
r 0.2
4VHPBB-7
0.016
Angle Regoiith Monitoring Well
Phase I Boring/Monitoring Well
GW-5t7 I -
ND HP-27
ND
0.00445
H
5
0 35 70
Scale In Feet
H P-21
0.00027
Notes:
1. PCE - Tetrachloroethene
2. Concentrations are given in
milligrams per liter.
TJ
3. Shallow depth interval is from
28 to 45 feet below ground surface.
-HP-22 GW-6❑
-0.00015 0.00031
4. Horizontal location of angle borings
are approximate.
Figure 4-27: WMU-B Shallow Groundwater PCE Isoconcentration Contours
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

!— 1H
= HP-20
053
W E
,R
S
1?7 - 0 35 70
GW-8 +, 5ca1e In feet
0.2 HP-1
2
HP-1B '
GW-4 0.23 HP-17
ND 46 0.87
HP-25 1
6 5.2 HP-18
HPBB-8 GW-3❑ 20 30 -
ND 3.1
12, GW-2D 38
�P-13
H
HP-8 12 38 HP-19
0.006OA5 0.017
HP-3i ? HP-6 ,l HP-2 HP-5
3.4 130 37 490
HPBB-9 W_1D 100 280
0.042 HPBB-1 HP-9 '150 280
N D 150
HP-4 HP-12
HP-30: 68 HP-3-- 0.057
0.36 HP-28 330 HP-21
HPBB-2 0.36 HP-11 ND
• N❑ ;' ~5.3 i Notes:
5.1 GW-5❑ O.00036
.P1. TCE - Trichloroethene
.1 00
HPBB-10 HP-29 1.4 -
N❑ A o HP-26 2. Concentrations are given in
1.4 HPBB-5 HPBB-6 �- milligrams per liter.
4.6
6P6B-3 iHPBB-
0.71 i 0.059
HPBB-11 ?+' 15.96 -----, 3. Deep depth interval is deeper than
ND HPBB-12 50 feet below ground surface.
ND HP-22 GW-6D
ND
�` fP ND 4. Horizontal location of angle borings
HPBB-7 are approximate.
1.934
* Vertical Hydropunch Boring 0 Angle Regoiith Monitoring Well Figure 4-28; WMU-B Deep Groundwater TCE Isoconcentration Contours
VaNI ■ Angle Hydropunch Boring # Phase I Boring/Monitoring Well RCRA Facility Investigation
Former Clifton Precision Site
Smith + Vertical Regolith Monitoring Well Murphy, North Carolina

HPBB-8
ND
46 HP 31
ND
1
HPBB-9 HPBB-1
0.00098 ND +
HP-30
0.0032
HPBB-2
N❑
46
O—ND-1Q
—0. .006 Q056
-HPBB-3c�
0.Q27
HPBB-11
6�-ND
li
HPBB-12
ND HPBB-4
& 0.026
GW-8
0.084
G W-4
N�
GW-3D
0.18
HP-8
0.00029�
HP-9
Ni
.033
4R7
HP-15
0.72
H P-2 5
0.94
HP-16
�
0.057 wHP-17
0.0075
HP-18
HP-7 0.47
0.95
HP-19
HP-13
HP-6
1.2 —GW-2D_o
0.012
40
�0.00018
1.3 HP-2
1.4
HP-5
24
GWAD
HP-1
0.59
12
HP-3
4.4
HP-12
n n77
HP-4
0.16
H P-28
0.0018
_ HP-11
HP-10 - 0.2
0.0017,-, 1,
Y HPBB-5� -
HP-26 0.033
0.017 GW-51D HPBB-6
1 � 0.23 Q.O�
-- 11 Alk—HIPBB0.055
67
Vertical Hydropunch Boring Angle Regolith Monitoring Well
CaN ■ Angle Hydropunch Boring Phase I Boring/Monitoring Well
Smith + Vertical Regolith Monitoring Well
H
S
0 35 70
Scale In feet
H P-21
ND
HP-2 Notes:
ND 1. PCE-TetrachIoroethene
2. Concentrations are given in
milligrams per liter.
3. Deep depth interval is deeper than
4-22 50 feet below ground surface.
ND GW-6D
ND 4. Horizontal location of angle borings
are approximate.
Figure 4-29: WMU-B Deep Groundwater PCE Isoconcentration Contours
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

Smith
Vertical Bedrock Monitoring Well
+ Angle Bedrock Monitoring Well
Figure 4-30: WMU-B Bedrock Groundwater TCE Concentrations
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

CDNI
Smith
Vertical Bedrock Monitoring Well
Angle Bedrock Monitoring Well
Figure 4-31: WMU-B Bedrock Groundwater PCE Concentrations
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

M W-51514.80
Shallow Regolith Monitoring Well + Angled Deep Regolith Monitoring Well
VOM Deep Regolith Monitoring Well —1615.2— Potentiometric Surface Contour
National Geodetic Vertical Datum, 1929
Smith + Recovery Well Interval = 1.4 feet
N
W E
S
0 35
Scale In Feet
NOW
Groundwater elevations measured on 12/20/2011
GW-5D GW-6S
1619.92 ■ 1522,61
rill
Figure 4-32: WMU-B Regolith Groundwater Potentiometric Surface Map
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina

N
W E
1
• S
0 35 70
scale In Feet
GW-8B
1614.300
W-6
1615.08
GW-713 Groundwater elevations measured on 12120/2011
1614.74 0 gW-1 B
ion 1615.97
tips GW-5b
1616.43
,pro
GW-6B
1*1617,02
Bedrock Monitoring Well
Smith Angled Bedrock Monitoring Well
—1615.2— Potentiometric Surface Contour
National Geodetic Vertical Datum, 1929
Interval = 0.3 feet
Figure 4-33: WMU-B Bedrock Groundwater Potentiometric Surface Map
RCRA Facility Investigation
Former Clifton Precision Site
Murphy, North Carolina