UNITED STATES
ENVIRONMENTAL PROTECTION AGENCY
REGION III
STATEMENT OF BASIS
BABCOCK & WILCOX NUCLEAR OPERATIONS GROUP FACILITY
LYNCHBURG, VIRGINIA
EPA ID NO. VAD 046 960 449
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Table of Contents
Introduction
Facility Background 1
Summary of Environmental Investigation,,...
A. RCRA Facility Investigation.... »....a..a.*...*»*»»...........a......a.2
B. James River Instream Studies. 4
C. James River Sentinel Wells..
D. Landfill 1 Investigations .a............«.aa....a*....a.aa........«». 5
E. Area A - Source Target Area Characterization
F. Area A - Boundary Target Area Characterization .......................a.**..a 7
(x. Interim IS^ejisures sind Pilot Tests m Area 8
EL Site wide Groundwater Monitoring ...»«....a.a.a.a.....................a9
I. Summary of Baseline Risk Assessment •aa-#a**B*..Baa...............aa.aeaB.....i.*.......B.B.a.a.»........ 9
J. Exposure Pathways. , »a.**«..............a.a..a*....a......9
K. RFI Risk Evaluation Results ....... 10
L. Ecological Risk assessment ••••••••.......a......••••••••••••••••.»••••••»»••••••••B...B.aa...........10
M. Vapor Intrusion Assessment .............a.#.....a...a..a.......*.........aa.................. 10
Corrective Action Objectives .........a.aa...a.............a...a.a.«...«.........a...a................................ 11
A. Soils ................aa..................a....................a....a.......................................a.a.a.............. 11
B. Subsurface Vapor Intrusion .......a.a..a.a...................a...................«.#...a.a...«.........*....aa. 11
C. Groundwater and Technical Impracticability *««».......a...........a..*.......#.*.*....*.*......... 11
Proposed Remedy ...........a.aa.................aa.a.a...................a.....................a..........................a.. 12
A. Soils • ••a..........a.a aa.aaa................a aa.a.a.a............aa.a.a«B................aaaaa..a...............a.aaa.aa a..... 12
B. Subsurface Vapor Intrusion ..a......................a.................................. 12
C. Groundwater - TI Zones with Long Term Monitoring aaaaaaaaaa...................a...a...... 13
D. Institutional Controls .....a.a.a...a.........a...*aaa...a a...........*......a....a........ 14
E. Development and Implementation of a Materials Management Plan................. 15
F. Implementation ......................a.a....................a.a...•a.............aa..aa..................a...aa......... 15
Evaluation of EPA's Proposed Remedy ..........a..................... a....'......... 16
A. Threshold Criteria ...a..a...............a.a.»a...............a.................................a...................... 16
1. Protect Human Health and the Environment. .......a............a...........a.aa... 16
2. Achieve Media Cleanup Objectives a.*....................a...........................a....a....... 17
3. Remediating the Source of Releases ..a.a...a.a.a....a..... 17
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B. Balancing/Evaluation Criteria 17
1. Long-Term Effectiveness 17
2. Reduction of Toxicity, Mobility, or Volume of the Hazardous
Constituents , 18
3. Short-Term Effectiveness 18
4. Implementability 18
5. Cost-Effectiveness 18
6. Community Acceptance 18
7. State/Support Agency Acceptance 18
VII. Environmental Indicators 19
VIII. Financial Assurance 19
IX. Public Participation 19
Attachments
Figure 1: Location Map
Figure 2: Monitoring Wells Location Map
Figure 3: TI Map Area A
Figure 4: TI Map Landfill 1
Figure 5: TI Map Area B
F igure 6: TI Map Area C
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I. Introduction
The United States Environmental Protection Agency (EPA) has prepared this Statement
of Basis (SB) to solicit public comment on its proposed remedy for the Babcock & Wilcox
(B&W) facility located at 1570 Mt. Athos Road in Lynchburg, Virginia (Facility). EPA's
proposed remedy consists of requiring the Facility to maintain a groundwater monitoring
program and to develop and maintain use restrictions known as Institutional Controls (ICs). This
SB highlights key information relied upon by EPA in making its proposed remedy.
The Facility is subject to EPA's Corrective Action Program under the Solid Waste
Disposal Act, as amended by the Resource Conservation, and Recovery Act (RCRA) of
1976, and the Hazardous and Solid Waste Amendments (HSWA) of 1984,42 IJ.S.C. §§
6901 et seq. (Corrective Action Program). The Corrective Action Program is designed to
ensure that certain facilities subject to RCRA have investigated and cleaned up any
releases of hazardous waste and hazardous constituents that have occurred at their
property.
EPA is providing a thirty (30)-dav public comment period on this SB. EPA may modify
its proposed remedy based on comments received during this period. EPA will announce its
selection of a final remedy for the Facility in a Final Decision and Response to Comments (Final
Decision) after the public comment period has ended.
EPA will make a decision after considering all comments received during the comment
period, consistent with applicable RCRA requirements and regulations. If the remedy is
substantially unchanged from, the one proposed, EPA will issue a Final Decision and inform all
persons who submitted written comments or requested notice of EPA's final determination. If
the final remedy is significantly different from the one proposed, EPA will issue a public notice
explaining the new remedy and will reopen the comment period. EPA will respond in writing to
each comment received.
Information on the Corrective Action program as well as a fact sheet for the Facility can
be found by navigating hHp / w w v.y.epa.au'v /rcg.nvcmd'correaivcaction.htm.
The Administrative Record (AR) for the Facility contains all documents,
including data and quality assurance information, on which EPA's proposed remedy is
based. See Section IX, Public Participation, for information on how you may review the
AR.
II. Fariiitv Backp iiund
The Facility is located in the northeast corner of Campbell County, Virginia, on
an oxbow of the James River (or River) approximately 2 miles northeast of the City of
Lynchburg. The 525-acre property is bounded by the James River on three sides (Figure
1), Lynchburg is located along the James River, upstream of the Facility. The
Lynchburg municipal wastewater treatment plant discharges into the James River several
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miles upstream of the Facility. Because of the treated water discharge, the water in this section of
the James River cannot be used as a public water supply. The Facility ceased using on-site
groundwater wells for potable water in 2003, and has been using water supplied by the City since
that time.
The Facility currently contains two commercial operations. One is owned and operated
by Babcock &Wilcox Nuclear Operations Group, Inc. and referred to as the B&W Property. The
other is owned and operated by AREVA Federal Services (AREVA) and is referred to as the
AREVA Property.
The B&W site is regulated by the Nuclear Regulatory Commission (NRC). The B&W
facility operates under an NRC license (SNM-42) for the management of its special nuclear
material and a Commonwealth of Virginia agreement state license for the management of the
other radioactive materials. The AREVA facility operates under a Commonwealth, of Virginia
Radioactive Materials License (680-515-1). NOG-L fabricates fuel-bearing precision
components that serve as power units for the nuclear navy. NOG-L is the sole source supplier of
these products and services in support of national security, and as such the Facility will remain in
operation as long as there is a U.S. nuclear navy. NOG-L operations can be expected to continue
well into the twenty-first century. AREVA supports the nation's commercial nuclear utility
outage, maintenance, and inspection business. The AREVA Property was formerly owned and
operated by B&W.
B&W maintains a decommissioning plan and subsequent standby trust agreement that
demonstrates financial assurance for decommissioning for the non-DOE operations performed at
the Facility. Adequacy of the decommissioning funding level is evaluated every 3 years. B&W
has contracts in place to cover the decommissioning of the DOE operations that are performed at
the Facility. During Facility decontamination and decommissioning, B&W will also address any
identified environmental issues to ensure that the Facility will not present a risk to human health
and/or the environment.
In 1991, EPA issued a Corrective Action Consent Order (Consent Order) to Babcock &
Wilcox Company pursuant to RCRA Section 3008(h) which specified that the Facility perform a
Resource Conservation and Recovery Act Facility Investigation (RFI), a Corrective
Measurement Study (CMS), and any interim measures at the Facility necessary to protect human
health and the environment.
111. Summary of Environmental Investigation
A. RCRA Facility Investigation
From 1987 to 1996. B&W performed an RFI focusing on three areas of groundwater
containing Volatile Organic Compounds (VOCs), primarily trichloroethylene (TCE). identified
during previous investigations. Three main groundwater contaminant plumes were identified:
Areas A, B, and C. Numerous groundwater monitoring wells (Figure 2) were installed at the
Facility to delineate the three groundwater plumes (37 in Area A, 14 in Area B, and 31 in Area
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C). Two small groundwater plumes under Landfill 1 (LF1) were also identified and delineated
with 14 groundwater monitoring wells. Landfill 1 groundwater plumes are adjacent to the Area
A plume. TCE does not dissolve readily in water and will enter the subsurface in the form of an
oily liquid, known as a Non-Aqueous Phase Liquid (NAPL). There are two classes of NAPLs:
light NAPLs (LNAPLs), such as gasoline, are less dense than water; dense NAPLs (DNAPLs),
such as trichloroethylene, are more dense than water. Samples of groundwater, soil, stream
sediment, and surface water were analyzed for VOCs and RCRA metals including arsenic,
barium, cadmium, chromium, lead, mercury, selenium and silver. Releases of chlorinated
solvents were identified and delineated at the following areas:
• Groundwater Area A (Study Area A-l)
• Former Landfill 1 (Study Area A-9)
• Former Bum Area (Study Area A-10) (wholly within the boundary of Groundwater Area A)
• Groundwater Area B (Study Area B-1)
• Groundwater Area C (Study Area C-l).
The groundwater plume in Area C is located under the A REV A Property. Groundwater
plumes A and B are located under the B&W Property. The RFI concluded that the constituents of
concern (COCs) for the Facility are chlorinated VOCs in. groundwater and surface water,
primarily trichloroethene (TCE) and tetrachloroethene (PCE), and their degradation products, cis-
1,2-dichloroethene (DCE) and vinyl chloride (VC). Nine halogenated VOCs were identified for
tracking by RFI and are analyzed in the ongoing water quality monitoring:
• Bromoform
• Chloroform
• cis-l,2-DCE
• trans-1,2-DCE
• 1,1-DCE
• PCE
• TCE
• Tri chloroll uoromethane
• Vinyl Chloride
Under the oversight of the Virginia Department of Environmental Quality (DEQ).
Landfills 2A and 2B were closed on November 2, 2009 with contaminated soils left in place. The
landfills were capped with engineered covers. Post-closure groundwater monitoring is being
performed at monitoring wells. Landfill 2 A straddles the western margin of the Area A
groundwater plume. Both landfills were created in the 1970's, when sludge from the waste
water treatment operations was placed in the landfills.
During performance of the RFI, the two Inactive Emergency Ponds (RFI Study Area A-6)
were found to be impacted by the groundwater from the Area A plume. The Emergency Ponds
when used, were actually surface impoundments for the flow through of spent non-radioactive
(Cold) and radioactive (Hot) acidic liquid waste solutions prior to neutralization at waste water
treatment facility. The Cold Pond was removed from service in September 1983 and the Hot
Pond in May 1984. The Hot Pond was of similar size as the Cold Pond and located immediately
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east of it. A Groundwater Recovery System (GWRS) was installed in the Hot Pond prior to its
closure in 1998 under the aegis of the NRC. The Cold Pond has been recently investigated by
the Facility in order to plan for its closure.
Numerous investigations have been performed since the RFI was completed and are
described in the following sections. The James River Instream Studies covered the Areas A and
B plumes. All the other subsequent investigations were conducted within the Area A plume or in
its vicinity. Several remedial pilot studies/interim measures have been performed by the Facility
in the Area A plume area since the completion of the RFI.
B. fames Kivvr Instream Studies
In 1997 and 1998, several studies were conducted at the Facility to determine if VOC-
contaminated groundwater posed a risk to the aquatic and benthic communities of the James
River. The places where the Area A and Area B groundwater plumes discharged into the James
River were investigated. The studies included sampling .River water and sediment for VOC-s, a
Rapid Bioassessrnent Protocol (RBP) III study of the riverbed benthic community, and a survey
for the endangered James River spiny mussel.
Low levels of VOCs were found in River water and bottom sediment but were judged to
indicate no ecological risk to the aquatic biologic community. VOC concentrations in Area B
surface water and sediment were below the ecological screening benchmarks. At Area A,
surface water VOC concentrations were below ecological screening benchmarks, but sediment at
two locations had VOC concentrations greater than the benchmark. Nonetheless, biological
sampling found the nearshore benthic macroinvertebrate community to be unimpaired. The
James River spiny mussel was not found in the stretch of River around the Facility because the
River habitat is not suitable for the spiny mussel to live.
Because the screening assessment for River sediment in Area A had mixed results, an
RBP III study was conducted in 1997 and 1998. The RBP III study determined that the health of
the James River adjacent to the Area A plume was not adversely impacted by groundwater
contamination.
Surface water sampling in Area A is currently part of the annual water monitoring
program to ensure VOC levels remain consistent with historical levels.
C. James River Sentinel Wells
In 2001, the groundwater monitoring well networks in Areas A and B were supplemented
by the installation of additional sentinel wells near the Riverbank: MWA-38 to MWA-40 in Area
A and MWB-15 to MWB-17 in Area B. A fourth sentinel well, MWA-41, was added in Area A
in 2004. These sentinel wells monitor groundwater quality as the plume discharges to the James
River. They have been included in the annual groundwater monitoring program.
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D, Landfill 1 Investigations
Landfill 1 lies west of the Area A plume. Filter cake was buried in eight shallow trenches
over an area of approximately one 1 acre. The filter cake was generated by treatment of
wastewater from the metal pickling process from 1973 to 1977. The filter cake was covered with
soil. The soil has re-vegetated naturally.
The filter cake solids consist approximately of 45 percent calcium fluoride, 40 percent
zirconium hydrous oxide, 10 percent calcium hydroxide, and 5 percent calcium sulfate. The filter
cake also contains hydroxides of metals such as iron, copper, and aluminum, and possibly
zirconium metal chips.
LF1 was investigated as Study Area A-9 during the RFI. Eight soil borings around LF1
were sampled for VOCs and metals. TCE was found in soil at concentrations up to 0.0425 parts
per million (ppm) at a depth of 6.5 feet below ground surface (bgs). The soil TCE
concentrations were below EPA Regional Screening Level (RSL) for residential soil; however,
they were above the soil screening level for the protection of groundwater value of 0.0018
mg/kg.
In 1999, forty-nine (49) shallow borings were drilled to determine the trench locations
and landfill cover thickness. These borings confirmed the existence of six covered trenches
containing filter cake. Trench soil cover ranges from 2.5 to 7.3 feet thick, with a mean thickness
of 4.3 feet. No samples for chemical analysis were collected during these drilling activities.
Subsequent groundwater monitoring in the vicinity of LF1 has shown that the water table
generally ranges from 4.3 to 8.6 feet bgs, but occasionally is very shallow. A follow up
investigation was completed in December 2001 to delineate the limits of two additional trenches
at LF1. The existence of waste outside the limits of the original six trenches became apparent
when filter cake was encountered while drilling a temporary monitoring well in November 2001.
Four (4) waste samples were collected in each trench to characterize the filter cake.
In 2001, a soil gas survey of the LF1 and surrounding area was performed by B&W. It
showed PCE and TCE hot spots in Trench 5, Trench 1, and between Trench 1 and monitoring
well FL-3. Subsequently, fourteen (14) shallow direct-push borings were advanced to
characterize the filter cake in the landfill trenches and soil immediately surrounding LF1. Five
(5 ) of the borings were placed within portions of Trenches 2 and 3 that were subsequently
excavated to characterize waste sludge and soil with radioactivity above NRC action levels.
NRC determined that only portions of Trench 2 and 3 required excavation. To minimize the
volumes of excavated material, B&W identified the specific area slated for removal and
surrounded the area with sheet piling driven to bedrock. Using a dewatering system, B&W was
able to successfully excavate the soil and waste and complete a NRC survey of the excavated
area for its closure.
In 2004, B&W excavated and removed the filter cake. Cobbles (small to large rocks)
prevented these direct-push borings from penetrating to the base of the alluvium. Soil and sludge
samples were analyzed for VOCs, and the sludge samples were also analyzed for additional
constituents important for the radiological removal action. VOCs were detected in four sludge
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samples collected within the area. The excavated soil and waste were managed as a Mixed
Waste (low-level radioactive and hazardous waste) and shipped to a licensed mixed waste
disposal facility. Because low-levels of radioactive remain in soil, LF1 remains under NRC
jurisdiction for closure.
Groundwater monitoring at LF1 began in 2001, at the same time as the sludge and soil
investigation. Nineteen (19) monitoring wells were installed in the alluvium. Fourteen (14) wells
were made permanent and added to the annual water quality monitoring program in 2002,
Groundwater sampling results indicated that there are two small solvent plumes in groundwater
near LF1. These two small plumes are separate from the Area A plume. One plume originates
near well FL-3, a short distance upgradient of the LF1 trenches, and contains mainly PCE. The
other less concentrated plume is located east-northeast of the trenches and the only constituent
with groundwater concentrations above the Maximum Contaminant Level (MCI,) is TCE
(maximum concentration 80 micrograms per liter [ug/Lj, MCL of 5 ug/1). Groundwater VOC
concentrations at the leading edges of the two small plumes are low and are not a threat to the
James River,
E, Area A - Source Target Area Characterization
The Source Target Area (STA) is located immediately down gradient of the former TCE
storage tank, which was the principal source of the Area A plume. The TCE storage tank was
located on a high terrace within the protected area of the Facility. From 2006 to 2008, site
characterization work to prepare for an in situ remedial pilot test was performed at the Facility.
Two successive investigations were performed during that time. Fifteen (15) wells were installed
in core-drilled borings. Pumping tests and slug tests were performed to estimate hydraulic
conductivities. In 2009, a groundwater tracer test and bench-scale bioremediation treatability
tests were performed to better define parameters and constraints for an in situ bioremediation
pilot test. A large man-made rock cut about 300 feet northeast of the STA was also examined.
Schist bedrock there strikes approximately parallel to the Facility grid north and about 85
degrees towards the east.
The rock cores were photographed and described in detail. The deepest zone of
weathering occurred in a narrow area that is being called the "weathered trough." The weathered
trough parallels the bedrock strike and presumably is a zone that is less resistant to weathering.
On a finer scale, the cores show that zones of severe weathering and slight weathering alternate
with depth, presumably as the borings crossed different beds or fracture sets. Pumping tests
showed the weathered trough has a relatively high hydraulic conductivity, roughly 3.2 feet per
day (1.1x10 centimeters per second). Hydraulic conductivity is highest in the direction of
bedrock strike.
In the weathered trough, high groundwater TCE concentrations (600,000 to 1.000,000
ug/L) were found in the weathered bedrock and extending deep into the unweathered bedrock.
A small volume (5 milliliters) of dense non-aqueous-phase liquid (DNAPL) was collected from
near the base of the weathered bedrock at well IWA-01, located in the STA Area, during well
development. Due to the presence of DNAPL in well IWA-01 and the high TCE concentrations
in other wells in STA, DNAPL is suspected of being presence in other wells in the weathered
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bedrock and deeper into unweathered bedrock.
The bromide tracer test demonstrated that groundwater flow has a significant downward
vertical trajectory. This flow is consistent with groundwater levels, which show a strong
downward hydraulic gradient. The tracer test measured groundwater flow velocities of 0.55 to
7.5 feet per day (200 to 2,700 feet per year) in the weathered bedrock and 0.5 to 0.8 feet per day
(180 to 290 feet per year) in the unweathered bedrock.
The water quality and treatability testing found that weathered bedrock groundwater is
slightly acidic to neutral. Deeper unweathered bedrock groundwater is strongly alkaline (pH
11.4 at MWA-42I)) and contains elevated concentrations of sodium, sulfate, and total organic
carbon. Aerobic conditions predominated in most of the STA groundwater, but portions of the
unweathered bedrock were anaerobic.
F. Area A - Boundary Target Area Characterization
The Boundary Target Area (BTA) is the portion of the Area A plume next to the James
River. BTA is referred to as the Former Bum Area in the RFI Report. In 2010 and 2011, site
characterization work was performed in preparation for an in situ bioremediation pilot test. The
investigation focused on the alluvium and, to a lesser degree, the shallow bedrock. Fourteen
additional monitoring wells were installed in and around the BTA.
Slug tests were performed on numerous wells to measure formation hydraulic
conductivity. The alluvium has a typical hydraulic conductivity of 2.1 feet per day. Groundwater
levels show a downward hydraulic gradient from the alluvium to the bedrock. This gradient
suggests the likely existence of more permeable zones in either the shallow bedrock or the
cobbly zone at the base of the alluvium. One of the shallow bedrock wells is screened in a
permeable weathered zone that yields as much water as the alluvium.
VOC contamination in groundwater at the BTA occurs in both the alluvium and bedrock.
VOC contamination extends to at least 150 feet bgs at well MWA-33D. The highest TCE and
cis-1,2- DCE concentrations in groundwater are in the alluvium (well MWA-63) and in the
shallow bedrock (MWA-66D and 67D). Groundwater VOC concentrations fluctuate
considerably in the BTA due to hydrological events (e.g., fluctuations in river stage or rainfall ).
For example, the TCE concentrations in MWA-63 were 19,000 ug/L in 2011 and 11,000 ug/L in
2013, but only 300 ug/L in 2012. Since 2001, TCE concentrations in MWA-16 typically ranged
from 2,050 to 7,400 ug/L, but dropped to 420 ug/L in 2010. TCE concentrations in MWA-41 are
typically greater than 10,000 ug/L but dropped to 100 ug/L in 2006. The TCE concentration in
MWA-15 was 19,000 ug/L in 2002, but has declined significantly since that time and has not
exceeded 100 ug/L since 2009. PCE has also been detected in BTA groundwater, at well MWA-
41, at concentrations up to 280 ug/L.
Groundwater redox conditions were moderately reducing before the in situ
bioremediation pilot test. The widespread presence in groundwater of dechlorination metabolic
byproducts like methane, ethane, and ethene is indicative of active biodegradation. The
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dechlorinating bacteria, Dehalococcoides, was present in significant amounts at some places, but
its distribution was spotty.
G. lute, i im Measures and Pilot Tests in Area A
The Facility started evaluating potential corrective measures in the early 1990's. Three
pilot tests were conducted. The three pilot, tests involved were as follows: (1) Soil Vapor
Extraction (SVE), (2) Vacuum-Enhanced Pumping (VEP), and (3) in situ Air Sparging (IAS).
An SVE system near the former TCE tank source (Area A) began operation in 1993. The SVE
system removed more than 14,000 pounds of TCE before the vadose soil at the former tank
location became exhausted. The SVE system has achieved its performance objective of removing
TCE from the vadose soil and is no longer in operation.
The VEP pilot test was conducted to evaluate the effectiveness of VEP and groundwater
extraction methods in removing TCE from the groundwater. The VEP system was located in the
center of the Area A groundwater plume, and downgradient from the source area. Operations
started in August 1995, and ran for about one year. The system was ineffective due to the VEP
recovery wells having very limited and uneven radius of influence on groundwater. The IAS
pilot test was conducted to evaluate the effectiveness of in situ air sparging to 'Volatilize and
remove dissolved concentrations of TCE from the groundwater at a location adjacent to the
James River on the northern edge of the Area A groundwater plume. Operations started in
August 1995 and ran thru November 1996. Groundwater data collected during the pilot test
indicate that air sparging had no measurable effect on the concentrations of TCE at this location.
The GWRS was installed when the low-level radioactive Inactive Emergency Pond (Hot
Pond) was closed under aegis of the NRC in 1998. The Hot Pond is located to the east of the
Cold Pond. The early version of the GWRS was originally meant to be a temporary dewatering
system to facilitate closure of the Hot Pond, but its design was expanded because the Facility
found its location to be advantageous for groundwater recovery in Area A. From around 1998
up through mid-2013, more than 1,600 pounds of TCE have been removed from groundwater.
The GWRS intercepts a large port ion of the shallow groundwater plume before it can reach the
river. The GWRS provides a significant but incomplete interception of the plume, as it does not
interdict the bedrock groundwater, and may not capture all the alluvial groundwater on the
eastern side of the plume. B&W proposes to continue operating the GWRS as a component of
the final remedy for the Facility.
In September 2012, the Facility conducted a pilot test of in situ enhanced anaerobic
bioremediation (EAR) at the Boundary Target Area of Area A. Post-injection groundwater
sampling was conducted in November 2012 and July 2013, and yielded incomplete degradation
of TCE to ethene. Similar tests at the Source Target Area showed degradation in a small area.
The results of these pilot tests concluded that in situ EAB is impractical over most of the Facility
property due to naturally aerobic groundwater condit ions and an excess of competing electron
acceptors, such as dissolved oxygen, nitrate, and sulfate. In situ bioremediation in unweathered
bedrock is impractical due to the low permeability of the formation, which hinders injection of
amendments, and the presence of a strongly alkaline groundwater pH at the STA. As a result,
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EAB pilot testing was discontinued in the ST A as well as at the BTA.
H. Site wide Groundwater Mornh >rn\s
From 2001 to the present, annual site wide monitoring and reporting of groundwater and
River water quality has been conducted consistently at the Facility. No other areas of concern
have been identified by the monitoring. This twelve (12) years of monitoring have shown that the
groundwater plume boundaries are stable and that concentrations of VOCs are generally stable or
decreasing.
I. Summ?i> ul s P.r k -ht
The baseline risk assessment performed during the RFI evaluated four areas:
• Area A
• Area A10 (Former Bum Area) ,
• Area B
• Area C
The Cold Pond (Area A-6) soil and sediment were not included in the baseline risk
assessment. A separate risk evaluation was performed In July 2011 for the Cold Pond,
subsequent to the detailed characterization of the pond soil and water for DEQ. The RFI
baseline risk assessment included a human health risk assessment and an ecological risk
assessment. The ecological risk assessment evaluated potential risks to terrestrial and aquatic
receptors.
J, Exposure Pathways
The human health risk assessment evaluated an industrial exposure scenario, assuming
that land use controls would be implemented and maintained to control exposures and restrict
future development. Therefore, the human health risk assessment did not evaluate exposure
pathways relating to residential land use or exposure to groundwater.
The human health risk assessment examined the following potential receptors:
• Outdoor maintenance worker
• Outdoor construction worker
• Trespassing child.
Exposures to the following environmental media were evaluated:
• Surface soil
• Subsurface soil
• Sediment (in small surface water drainage features)
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• Surface water (springs and small surface water drainage features).
In the RJFI Report, there was no evaluation of exposure from vapors from VOC-
contaminated groundwater plumes under or near occupied buildings. The CMS did evaluate the
potential risk to human health from exposure to vapor intrusion into occupied buildings. The
vapor intrusion pathway was evaluated during the CMS phase because the potential significance
of this exposure pathway was realized after the RFI was completed. See Section IIJ.M below for
vapor findings under CMS.
iv RFI Risk Evaluation Results
The RFI human health risk assessment concluded that VOCs and metals posed no
significant risks to human health under an industrial land use scenario. The human health risk
assessment in the RFI Report evaluated environmental media by Area. The presence of metals in
all four Areas were deemed to be background, but were included in the risk evaluation
nonetheless. No immediate risks were identified at any of the Areas that would necessitate
interim remedial measures.
L, Ecological Risk assessment
The ecological risk assessment in the RFI Report evaluated each study area and
concluded that there are no present or future risk to either terrestrial or aquatic receptors.
M. Vapor Intrusion Assessment
There are buildings overlying portions of the groundwater Area A and Area C plumes. In
May 2014, during the CMS, the Facility submitted an Indoor Air Quality Assessment Report
detailing the results of indoor air sampling conducted in those buildings. The plume
contaminants are primarily TCE, cis-1,2-diehloroethene and vinyl chloride.
Sampling was performed on March 8 and 9, 2014. Ten composite samples of indoor air
were collected using SUMMA canisters. Only Building K in Area A. near the source Target
Area had TCE concentrations exceeding EPA's non-cancer RSL of 8.8 micrograms (ug) per
cubic meter of air.
The Facility modified the ventilation intake air for Building K, since the intake is at
ground level. The Facility then completed a comprehensive indoor air monitoring on August 31,
2014, after the ventilation system modification was completed. The results from the indoor and
ambient air monitoring indicate TCE concentrations below the EPA non cancer RSL of 8.8
ug/cubic meter. The Facility will repeat the monitoring in the winter, when sub-slab vapors may
migrate into buildings when the ground is frozen. Additional measures such as introduction of
additional ambient air or the design of a sub-slab depressurization system may be necessary to be
installed pending results of next indoor air sampling of Building K.
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IV. Correctii tion Objectives
EPA's Corrective Action Objectives for the Facility are the following:
A.
EPA has determined that EPA RSL for Industrial Soils for direct contact with soils are
protective of human health and the environment for individual contaminants at this Facility,
provided that the Facility is not used for residential purposes. Therefore, EPA's Corrective
Action Objective for Facility soils is to attain (SLs) for Industrial Soils and to control exposure to
the hazardous constituents remaining in soils by requiring the compliance with and maintenance
of land use restrictions.
B. Subsurface Vapor Intrusion
EPA's Corrective Action Objective for subsurface vapor intrusion is to attain
EPA's Subsurface Vapor Intrusion Guidance screening levels. EPA has determined that those
levels are protective of human health and the environment at this Facility provided that the
Facility buildings are not used for residential purposes.
C. Groundwater and Technical Impracticability
EPA expects final remedies to return usable groundwater to its maximum beneficial use,
where practicable, within a timeframe that is reasonable. Where returning contaminated
groundwater to its maximum beneficial use is not technically practicable, EPA generally expects
facilities to prevent or minimize the further migration of a plume, prevent exposure to the
contaminated groundwater, and evaluate further risk reduction. Technical impracticability (TI)
for contaminated groundwater refers to a situation where achieving groundwater cleanup
standards associated with final cleanup standards is not practicable from an engineering
perspective. The term "engineering perspective" refers to factors such as feasibility, reliability,
scale or magnitude of a project, and safety.
EPA has determined that restoration of groundwater to drinking water standards known
as Maximum Contaminant Levels (MCLs), promulgated at 40 C.F.R. Part 141 pursuant to
Section 1412 of the Safe Drinking Water Act, 42 U.S.C. Section 300g-l, at the Facility is
technically impracticable in all three groundwater plume areas for the following reasons;
1) COCs are present as unrecoverable DNAPL.
2) Steeply dipping rock bedding planes and a downward hydraulic gradient promote
deep penetration of contamination.
3) In the bedrock, low permeability and unpredictability of water-producing fractures
makes pumping for extraction or injection for in situ treatment infeasible.
11
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4) TCE DNAPL has been confirmed in bedrock at the STA in Area A and is suspected
at several other locations, including Landfill 1 and Area C, based on elevated
groundwater concentrations. PCE DNAPL is suspected at Area B based on the high
concentrations of PCE in bedrock groundwater wells.
5) TCE and PCE are trapped in the primary and secondary porosity of bedrock. The
trapped VOCs will be a continuing source of groundwater contamination for many
years as it slowly diffuses back out of the rock.
6) Matrix storage of TCE and PCE in fractured rock is suspected over large areas and to
depths greater than 100 feet, making the scope of groundwater cleanup technically
impracticable.
Therefore, EPA's Corrective Action Objectives for Facility groundwater are to control
exposure to the hazardous constituents remaining in the groundwater: protect the current existing
receptors, namely bedrock and the James River, from unacceptable concentrations from COC
impacts: ensure that the dissolved groundwater plume is contained and will not migrate beyond
the extent of the current groundwater plume; demonstrate mass loss of the contaminated
groundwater plume over time or distance from known source areas; and ensure that no
groundwater discharge concentrations would result in surface water concentrations that are
above the VADEQ surface water criteria.
V. Proposed Remedy
The proposed remedy for the Facility consists of land and groundwater use restrictions,
known as institutional controls (ICs), and the continued implementation of the GWRS until
groundwater clean-up standards are met. The goal of the proposed remedy is to ensure the
overall protection of human health and the environment.
A. Soils
Based on the available information, there are currently no unacceptable risks to human
health and the environment via the soil for the present and anticipated use of the property
(Industrial use). Because contaminants will remain in Facility soils above levels appropriate for
residential uses, the proposed remedy for soils is land use restrictions (See Section D below) to
restrict the Facility to non-residential uses.
B. Subsurface Vapor Intrusion
Buildings located above a contaminated groundwater plume are vulnerable to subsurface
vapor intrusion coming from the plume and entering through cracks, joints and utilities openings.
In 2014, B&W did conduct a vapor intrusion assessment of buildings located over the Areas A
and C groundwater plumes. Based on those results, B&W modified the ventilation system in
Building K and conducted a comprehensive indoor air monitoring in that building after the
modification was completed. Analytical results from the indoor air sampling collected on
12
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August 31,2014, showed TCE indoor levels below the EPA non cancer RSL of 8.8 ug/cubic
meter. Another round of indoor air sampling will be conducted in February 2015 to monitor
vapor movements during the colder months. In addition, due to the known presence of VOC
contamination in the groundwater beneath the Facility, EPA will require that all new buildings
have vapor control systems installed.
C. Groundwater - TI Zones with Long Term Monitoring
Given the elevated levels and the non-aqueous phase liquid (NAPLs) characteristics of
the VOC contamination and the constraints of the hydrogeological conditions (i.e., fractures and
bedding planes in the bedrock) at the Facility, EPA has concluded that it is technically
impracticable to attain MCLs throughout the three groundwater plume Areas and LF1 within the
Facility property boundaries. It is often necessary to remove virtually all NAPL before
concentration levels in groundwater near the source of the contamination can approach
concentration levels commensurate with the MCLs. Presently, there are no technologies which
have been proven to be economical and capable of removing all NAPL in groundwater from
large facilities where NAPL is widely distributed laterally and vertically, and where the
stratigraphy is highly heterogeneous and complex as presented at the Site. EPA evaluated over
twelve years of Site groundwater data and regional hydrogeology investigation to conclude that
total removal of VOC contamination in bedrock fractures is effectively impossible and that
attainment of MCLs within the three groundwater plumes within the property boundaries is
technically impracticable. Additional details of the Facility analyses and evaluation of the VOC
groundwater data in heterogeneous bedrock fractures are presented in the Final RFI Report.
Because of the constraints of VOC contamination in groundwater and the r
hydrogeological conditions at the Site that prevent MCL attainment throughout the groundwater
plume, EPA is proposing that continued operation of the existing groundwater pump and treat
system in the A Area and groundwater monitoring in all three Areas and LF1, along with the
establishment of four Technical Impracticability Zones (TI Zones) will be the most practical and
economical remedy that will continue to be protective of human health and the environment.
These TI zones will define the area of hydraulic control that will ensure groundwater
contamination stability within the Facility property. Long-term monitoring is proposed through
performance sampling and gauging of the proposed TI Boundary monitoring well network.
The proposed TI Zones will include the groundwater plumes and associated contaminated
surface water such as, springs and small streams. Specifically, the proposed TI Zone areas are:
• Area A plume, both alluvium and bedrock, springs, and small surface water drainage
features (Figure 3)
• LF1 plume, both alluvium and bedrock (Figure 4)
• Area B plume, both alluvium and bedrock, and small surface water drainage features
(Figure 5)
• Area C plume, both alluvium and bedrock. (Figure 6)
Based on the data collected during the CMS. the groundwater plume appears to be stable
(not migrating), and concentrations of constituents of concern are stable and declining over time.
13
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Groundwater is not used on the Facility for drinking water, and there are no down gradient users
of off-site groundwater located between the Facility boundary and the James River. Therefore,
the proposed remedy for the groundwater is the combination of groundwater use restrictions (See
Section D, below), establishment of TI Zones, surface water monitoring, and a groundwater
monitoring program for COC's within the Tl Zones to ensure groundwater outside these TI
Zones remain below MCLs.
D. Institutional trols
Because some contaminants remain in the soil and groundwater at the Facility at levels
which exceed residential use, EPA's proposed remedy requires the compliance with and
maintenance of land and groundwater use restrictions.
EPA is proposing the following use restrictions be implemented at the Facility:
1. Groundwater at the Facility shall not be used for any purpose other than to conduct the
operation, maintenance, and monitoring activities required by VADEQ and/or EPA, unless
it is demonstrated to EPA, that such use will not pose a threat to human health or the
environment or adversely affect or interfere with the selected remedy and EPA provides
prior written approval for such use;
2. No new wells will be installed on Facility property unless it is demonstrated to EPA that
such wells are necessary to implement the final remedy and EPA provides prior written
approval to install such wells.
3. The Facility property shall not be used for residential purposes unless it is demonstrated to
EPA that such use will not pose a threat to human health or the environment or adversely
affect or interfere with the selected remedy, and EPA provides prior written approval for
such use;
4. All earth moving activities, including excavation, drilling and construction activities, in the
areas at the Facility where any contaminants remain in soils above EPA Region Ill's
Screening Levels for Industrial Soils or in groundwater above their MCLs or EPA Region
Ill's Tap Water RBCs, shall be prohibited unless it is demonstrated to EPA that such
activity will not pose a threat to human health or the environment or adversely affect or
interfere with the selected remedy, and EPA provides prior written approval for such use. In
the event of such approval, a Materials Management Plan specifying protocols for soil,
groundwater, and surface water within the plume areas will be created for all earth moving
activities and submitted in writing to EPA for review and approval;
5. A vapor intrusion control system, the design of which shall be approved in advance by EPA,
shall be installed in each new structure constructed above the contaminated groundwater
plume or within 100-foot around the perimeter of the contaminated groundwater plume,
unless it is demonstrated to EPA that vapor intrusion does not pose a threat to human health
and EPA provides prior written approval that no vapor intrusion control system is needed;
14
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6. The Property will not be used in a way that will adversely affect or interfere with the
integrity and proteetiveness of the final remedy selected by EPA in the Final Decision and
Response to Comments (FDRTC).;
7. EPA, VADEQ, and/or their authorized agents and representatives, shall have access to the
Property to inspect and evaluate the continued effectiveness of the final remedy and if
necessary, to conduct additional remediation to ensure the protection of the public health and
safety and the environment based upon the final remedy selected in the FDRTC.
Development and Implementation of a Materials Management
EPA's proposed remedy requires the development and implementation of a Materials
Management Plan to be submitted for review and approval by EPA before any earth moving
activities, including construction and drilling, can be conducted on areas known to contain COCs.
The Materials Management Plan will detail how soil and groundwater will be managed during any
future subsurface activities conducted at the Facility. The Materials Management Plan will detail
how all excavated soils will be handled and disposed. All soils that are to be disposed of shall be
sampled and disposed of in accordance with applicable State and Federal regulations. The
Materials Management Plan will include analysis of constituents detected at the Facility not
previously identified.
Soil remediation cleanup standards will be EPA's RSL for industrial soil. In addition, the
Materials Management Plan will include soil stabilization requirements to minimize contact
between storm water runoff and the parcel soils. Soil stabilization measures may include the
construction of berms to prevent storm water from flowing onto certain areas as well as the
construction of sumps with pumps to remove ponded water from low lying areas.
F. ]
EPA proposes to implement the land and groundwater use restrictions necessary to
prevent human exposure to contaminants at the Facility through an enforceable mechanism such
as an order, permit and/or an Environmental Covenant pursuant to the Virginia Uniform
Environmental Covenants Act (UECA). Title 10.1, Chapter 12.2, §§10.1-1238 - 10.1-1250 of the
Code of Virginia. If an Environmental Covenant is selected, it will be recorded in the chain of
title for the Facility property.
In addition, the Commonwealth of Virginia State Board of Health Private Well
Regulations, 12 VAC 5-630-10 et seq. (Regulations) and its implementing statute set forth at the
Code of Virginia, Title 32.1 (Health), Chapter 6 (Environmental Health Services), Va. Code
§32.1 is an institutional control mechanism that will reduce potential human exposure to
contaminated groundwater attributable to the Facility. Pursuant to Section 12 VAC 5-630-30, the
purpose of these Regulations is to "ensure that all private wells are located, constructed and
15
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maintained in a manner which does not adversely affect ground water resources, or the public
welfare, safety and health."
Accordingly, Section 12 VAC 5-630-230 through 12 VAC 5-630-270 of the Regulations
prescribes the process by which construction permits for the installation of private wells are
received and issued. Pursuant to the Regulations, if a private well is installed or modified without
a permit, Section 12 VAC 5-630-150 sets forth an enforcement mechanism which provides for
the notification of violations of the Regulations, the issuance of orders requiring cessation and
correction of violations, appropriate remedial action to ensure that the violation does not recur,
and any appropriate corrective action to ensure compliance with the Regulations.
VI. Evaluation of EPA's Proposed Remedy
This section provides a description of the criteria EPA used to evaluate the proposed
remedy consistent with EPA guidance titled, "Corrective Action for Releases From Solid Waste
Management Units at Hazardous Waste Management Facilities: Proposed Rule," 61 Fed. Reg.
19431, May 1,1996. The criteria are applied in two phases. In the first phase, EPA evaluates
three remedy threshold criteria as general goals. In the second phase, for those remedies which
meet the threshold criteria, EPA then evaluates seven balancing criteria.
A. Threshold Criteria
1. Protect Human Health and the Environment
With respect to groundwater, while contaminants remain in the groundwater beneath the
Facility in areas designated as TI Zones, the contaminants are contained in the aquifer and are
not migrating beyond the areas on the Facility property. For this reason, the area of
contaminated groundwater is contained. Groundwater monitoring of contaminants within the TI
Zones will ensure groundwater outside these TI Zones remain below MCLs. The Facility has
been using city water since 2003, therefore groundwater is not used at the Facility for potable
use. With respect to future uses, the proposed remedy requires groundwater use restrictions for
groundwater in the TI Zone to minimize the potential for human exposure to contamination and
protect the integrity of the remedy.
With respect to Facility soils, all contaminated soil is below the surface and contained
within Facility property. There is no direct exposure of industrial workers to subsurface soil
under current land use. With respect to future uses, HP A proposes to limit the Facility to
industrial use in order to minimize the potential for human exposure to contamination. Because
of the existing RCRA regulated Landfill 2, NRC managed Landfill 1, as well as ongoing
operations at the Facility with nuclear components, an industrial use designation for the property
is appropriate.
16
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2, Achieve Media Cleanup Objectives
The Facility has achieved the EPA's RSL for industrial soils. For groundwater, site
geologic conditions (i.e. fractured bedrock) and presence of DNAPL within those fractures
makes achieving MCLs not practicable from an engineering perspective. Under the proposed
remedy, groundwater with COC levels that exceed MCLs will remain within the 11 Zones.
Long-term monitoring is proposed through performance sampling and gauging of the proposed
TI Boundary monitoring well network. Long term groundwater monitoring will ensure
contaminated groundwater remains in the TI Zones The groundwater plume appears to be stable
(not migrating), and COCs though above MCLs are either stable or declining over time.
Groundwater outside the TI zones meets drinking water standards. EPA's proposed remedy
requires the implementation and maintenance of institutional controls to ensure that Facility
property is not used for residential purposes and groundwater beneath Facility property is not
used for any purpose except to conduct the operation, maintenance, and monitoring activities
required by VADEQ and/or EPA.
3. Reatcduting the Source of ttoU'tn*ps
In all proposed remedies, EPA seeks to eliminate or reduce further releases of hazardous
wastes and hazardous constituents that may pose a threat to human health and the environment.
There are no remaining large, discrete sources of waste from which constituents would be
released to the environment. With respect to existing releases at the Facility, remediating
groundwater COCs to applicable their MCLs has been demonstrated to be technically
impracticable. The existing GWRS will assist in protecting the James River from concentrations
that would cause unacceptable risk from COCs. Therefore, EPA has determined that this
criterion has been met.
B. Ealancmg/f:v<\1a,irtou¦ nleria
1. Long-T
The proposed use restrictions will maintain protection of human health and the
environment over time by controlling exposure to the hazardous constituents remaining in soils
and groundwater. EPA anticipates that the land use and groundwater use restrictions will be
implemented through an order, permit and/or an environmental covenant under UECA to be
recorded in the chain of title for the Facility property. If the mechanism is to be an
environmental covenant, the environmental covenant will run with the land and as such, will be
enforceable by EPA. In addition, a groundwater monitoring program already in place will
continue until groundwater clean-up standards are met. The existing GWRS will assist in
protecting the James River from concentrations that would cause unacceptable risk from COCs.
17
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has already been achieved, as demonstrated by the groundwater monitoring data showing that the
plume appears to be stable (not migrating), and concentrations of constituents of concern (COCs)
are either stable or declining over time. In addition, a groundwater monitoring program already
in place will continue to monitor the groundwater contamination stability in the TI zones. The
existing GWRS will assist in protecting the James River from concentrations that would cause
unacceptable risk from COCs.
3. Short-Term Effectiveness
EPA's proposed remedy does not involve any activities, such as construction or
excavation that would pose short-term risks workers, residents, and the environment. A
groundwater monitoring program already in place will continue until groundwater clean-up
standards are met. In addition, EPA anticipates that the land use and groundwater use
restrictions will be fully implemented shortly after the issuance of the FDRTC.
4. Implementability
EPA's proposed remedy is readily implementable. EPA proposes to implement the use
restrictions through an enforceable mechanism such as an order, permit or an Environmental
Covenant pursuant to UEC A.
5. Cost-Effectiveness
Because EPA has determined that TI applies to groundwater in three Areas and at LF1, the costs
associated with implementing this proposed remedy are the most cost effective. If the IC
mechanism to be selected is an environmental covenant, the cost to record an environmental
covenant in the chain of title of the Facility property is minimal.
6. Community Acceptance
EPA will evaluate community acceptance of the proposed remedy during the public
comment period, and it will be described in the FDRTC.
7. State/Support Agency Acceptance
EPA has solicited VADEQ input and involvement throughout the investigation process at the
Facility. VADEQ is reviewing EPA's proposed remedy for the Facility and will comment or
concur during the public comment period.
IB
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¥11. Environi
EPA sets national goals to measure progress toward meeting the nation's major
environmental goals. For Corrective Action, EPA evaluates two key environmental indicators
for each Facility: (1) current human exposures under control and (2) migration of contaminated
groundwater under control. EPA determined that the Facility met these indicators on February
25,2000.
•"inancial Assurance
B&W will be required to demonstrate and maintain financial assurance for completion of the
remedy pursuant to the standards contained in Federal regulations 40 C.F.R. § 264.145 and 40 CFR §
264.143
IX. Public P:m iripation
Before EPA makes a final decision on its proposal for the Facility, the public may
participate in the remedy selection process by reviewing this SB and documents contained in the
Administrative Record (AR) for the Facility. The AR contains all information considered by
EPA in reaching this proposed remedy. It is available for public review during normal business
hours at:
U.S. EPA Region III
1650 Arch Street
Philadelphia, PA 19103
Contact: Mike Jacobi
Phone:(215) 814-3435
Fax: (215)814-3113
Email: JacobiMi .gov
Interested parties are encouraged to review the AR and comment on EPA's proposed
remedy. The public comment period will last thirty (30) calendar days from the date that notice
is published in a local newspaper. You may submit comments by mail, fax, or e-mail to Mike
Jacobi. EPA will hold a public meeting to discuss this proposed remedy upon request. Requests
for a public meeting should be made to Mike Jacobi.
19
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EPA will respond to all relevant comments received during the comment period. If EPA
determines that new information warrant a modification to the proposed remedy, EPA will
modify the proposed remedy or select other alternatives based on such new information and/or
public comments. EPA will announce its final decision and explain the rationale for any changes
in a FDRTC. All persons who comment on this proposed remedy will receive a copy of the
FDRTC. Others may obtain a copy by contacting Mike Jacobi at the address listed above.
Land and Chemicals Division
US EPA, Region III
20
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-------
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FIGURE 1
SITE LOCATION MAP
SOURCE'
KELLY, VIRGINIA QUADRANGLE USGS
7.5 MINUTE TOPOGRAPHIC MAP
¦ QUADRANGLE LOCATION'
FINAL CORRECTIVE MEASURES STUDY
THE BABCOCK * WILCOX COMPANY
NUCLEAR OPERATIONS GROUP
ML ATHOS SITE
LYNCHBURG, VIRGINIA
Shaw Environmental, Inc.
(A CB&I Company)
<3fb
-------
BOUNDARY TARGET
AREA B
LEGEND
~JWH
•MA-tO
0.005 mg/L)
PROPERTY BOUNDARY
\
NOTES
1. SOME WELLS IN THE SOURCE AND BOUNDARY
TARGET AREAS HAVE BEEN OMITTED FOR
CLARITY.
-------
NOTES
1. MCLs IN PART PER BILLION (ppb>=
PCE - 5ppb
TCE - 5pob
c»-1.2-DCE - 70ppb
VC - 2ppb
2. SOME WELLS AT THE SOURCE AND BOUNDARY
TARGET AREAS OMITTED FOR CLARITY.
3. WELL SYMBOLS OMTTED M THE SOURCE
TARGET AREA FOR CLARITY.
FIGURE 3
Tl WAIVER ZONE, AREA A
LEGEND
0MWA-61
(2012)
0MWA-1B
¦0-MWA-5D
(2012)
9GWRS
Asve
5
70--
2
SHALLOW MONITORING WELL WITH
VOC CONCENTRATIONS > MCL« AT
LEAST ONCE BETWEEN 2001 AND
2013 (DATE OF LAST EXCEEDANCE
SHOWN)
SHALLOW MONITORING WELL WITH
VOC CONCENTRATIONS < MCL«
BETWEEN 2001 AND 2013
DEEP BEDROCK MONITORING WELL
WFTH VOC CONCENTRATIONS > MCLs
AT LEAST ONCE BETWEEN 2001
AND 2013 (DATE OF LAST
EXCEEDANCE SHOWN)
GROUNDWATER RECOVERY SYSTEM
SUMP
SOIL VAPOR EXTRACTION SYSTEM
(INACTIVE)
Tl WAIVER ZONE
TOTAL VOC® CONCENTRATION
CONTOUR ABOVE MCLs (JUNE 2012)
VOC CONCENTRATION CONTOURS
ABOVE MCLs (JUNE 2012) (ppb):
SHALLOW PCE
SHALLOW TCE
DEEP BEDROCK TCE
SHALLOW ds-1,2-DCE
DEEP BEDROCK ds-1,2-DCE
SHALLOW VC
FINAL CORRECTIVE MEASURES STUDY
THE BABCOCK & WfLCOX COMPANY
NUCLEAR OPERATIONS GROUP
MT. ATHOS SITE
LYNCHBURG, VIRGINIA
Shaw Environmental, Inc.
(A CB&I Company)
-------
//
LEGEND
©FL-3
<2012)
©FL-5
SHALLOW MONETORING WELL WITH
VOC CONCENTRATIONS > MCLa AT
LEAST ONCE BETWEEN 2001 AND
2012 (DATE OF LAST EXCEEDANCE
SHOWN)
SHALLOW MONITORING WELL WITH
VOC CONCENTRATIONS < MCLb
BETWEEN 2001 AND 2012
• Tl WAIVER ZONE
TOTAL VOCs CONCENTRATION
CONTOUR ABOVE MCLb (JUNE 2012)
VOC CONCENTRATION CONTOURS
ABOVE MCLs (JUNE 2012) (ppb):
SHALLOW PCE
SHALLOW TCE
~0U> «AVAV.HA^C^1i
/
\ /
\
LANDFILL \
2B \
¦ \
/
NOTES
1. MCLs IN PART PER BILLION (ppb):
PCE - 5pp6
TCE - 5pi*
FIGURE 4
Tl WAIVER ZONE, LANDFILL 1
FINAL CORRECTIVE MEASURES STUDY
THE BIBCOCK t> WILCO, COMPANY
NUCLEAR OPERATIONS GROUP
UT. ATHOS SITE
LYNCHBURG, VIRGINIA
Environmental, Inc.
(A CB&I Company)
-------
LEGEND
0MWB-15
r <>MWB-1
(2003
ID
(2003)
-0-MWB-14-D
SHALLOW MONITORING WELL WITH
VOC CONCENTRATIONS > MCLs AT
LEAST ONCE BETWEEN 2001 AND
2013 (DATE OF LAST EXCEEDANCE
SHOWN)
SHALLOW MONrTORING WELL WITH
VOC CONCENTRATIONS < MCLs
BETWEEN 2001 AND 2013
BEDROCK MONITORING WELL WrtH
VOC CONCENTRATIONS > MCLs
AT LEAST ONCE BETWEEN 2001
AND 2013 (DATE OF LAST
EXCEEDANCE SHOWN)
BEDROCK MONITORING WELL WITH
VOC CONCENTRATIONS < MCLs
BETWEEN 2001 AND 2013
¦ Tl WAIVER ZONE
TOTAL VOCs CONCENTRATION
CONTOUR ABOVE MCLs CJUTf 2012)
VOC CONCENTRATION CONTOURS
ABOVE MCLs (JUNE 2012)
-------
LEGEND
©MWC-W
(2004)
0MWC-15
-0-MWC-12D
(2012)
<>MWC-31D
70
-2 —
SHALLOW MONTORING WELL WITH
VOC CONCENTRATIONS > MCLs AT
LEAST ONCE BETWEEN 2001 AND
2012 (DATE OF LAST EXCEEDANCE
SHOWN)
SHALLOW MONTORING WELL WITH
VOC CONCENTRATIONS < MCLs
BETWEEN 2001 AND 2012
DEEP BEDROCK MONITORING WELL
WITH VOC CONCENTRATIONS > MCLs
AT LEAST ONCE BETWEEN 2001
AND 2012 (DATE OF LAST
EXCEEDANCE SHOWN)
DEEP BEDROCK MONITORING WELL
WITH VOC CONCENTRATIONS < MCLs
BETWEEN 2001 AND 2012
• Tl WAIVER ZONE
TOTAL VOCs CONCENTRATION
CONTOUR ABOVE MCLb (JUNE 2012>
VOC CONCENTRATION CONTOURS
ABOVE MCLs (JUNE 2012) (ppb)*
SHALLOW TCE
DEEP BEDROCK ds-1,2-DCE
DEEP BEDROCK VC
NOTES
1. MCLs IN PART PER BILLION (ppb)=
TCE - Sppb
ci«-1,2-0CE - 70ppb
VC - 2ppb
FIGURE 6
Tl WAIVER ZONE, AREA C
FINAL CORRECTIVE MEASURES STUDY
THE BABCOCK fr WILCOX COMPANY
NUCLEAR OPERATIONS GROUP
MT: ATHOS SITE
LYNCHBURG, VIRGINIA
Shaw Environmental, Inc.
(A CB4I Company)
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