PB99-963912
EPA541-R99-016
1999
EPA Superfund
Record of Decision:
USA Vint Hill Farms Station
AREEs 9,11,19, & 21
Warrenton, VA
7/1/1999
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FINAL
DECISION DOCUMENT
AREEs9, 11,19, AND 21
VINT HILL FARMS STATION
WARRENTON, VIRGINIA
7775
Prepared for:
U.S. Army Communications-Erectronics Command
Prepared by:
IT Corporation
Edgewood, Maryland
June 1999
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4.3 AREE 19 - Pistol Range
4.4 AREE 21 - Sand Filter Beds
TABLE OF CONTENTS
Section
1.0 INTRODUCTION
[[[ • [[[ 1
2.0 SITE BACKGROUND ..................... ................................
3.0 SITE CHARACTERISTICS .............................. .'
3.1 Site Topography ............................. [[[ """ ............ \
3.2 Adjacent Land Use ................................ " .................. ................................................. ' ................. *
3.3 Surface Water Hydrology ....................... !"""ZZ"Z [[[
3.4 Geology/Hydrogeology ................................. !ZZ!!!"!!!"ZZ!! .................
x
4.0 SITE HISTORY AND INVESTIGATION FINDINGS
4.1 AREE 9 - Vehicle Maintenance Area .............................. '."."'.. [[[ 5
4.2 AREE 1 1 - Former Sewage Treatment Plant [[[ c
5.0 SUMMARY OF SITE RISKS
5.1 AREE 9 -Vehicle Maintenance Area. .Z"Z^!"ZIZ".ZZZ! 12
5.2 AREE 11 - Former Sewage Treatment Plant 10
5.3 AREE 19 - Pistol Range ' ',
5.4 AREE 21 - Sand Filter Beds ZZ"'ZZ.ZZZ! 13
6.0 REMEDIAL ACTION OBJECTIVES
*** *"* *••— 1 o
7.0 CLEANUP LEVELS ESTABLISHED FOR THE SELECTED ALTERNATIVE : 14
8.0 SUMMARY OF REMEDIAL ALTERNATIVES
8.1 Alternative 1 - No Action "ZZ!!"".'"! 14
8.2 Alternative 2 - Soil Removal.... \.
' 14
9.0 EVALUATION OF ALTERNATIVES
9.1 Overall Protection of Human Health and the Environment IR
9.2 Compliance with ARARs '°
9.3 Long-term Effectiveness and Permanence Z"1"!!!^ZZ"!" 17
9.4 Reduction of Toxicity, Mobility, or Volume Through Treatment 17
9.5 Short-term Effectiveness '
9.6 Implementability . .i.
9.7 cost !.!!!"!!!"!"""Z" 7
9.8 Regulator Acceptance Z"""!"Z"""!!"Z 17
9.9 Community Acceptance ]0
I O
10.0 SELECTED REMEDY AND STATUTORY DETERMINATIONS -, a
10.1 Selected Remedy '°
10.2 Statutory Determinations Z!!"""!ZZ!Z!!!ZIZ!"!"!" 18
10.2.1 Protection of Human Health and the Environment 18
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TABLE OF CONTENTS (Continued)
Section
11.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION
12.0 RESPONSIVENESS SUMMARY ............ . [[[ 20
12.1 Selected Newspaper Notices [[[ ..Z.l"".".!l.."."". ...................... 20
12.2 Comments Raised During the Public Meeting on September 18, 1997 ........................ 20
12.3 Public Meeting Attendance Roster ............................................... .'..... ZZZ ....................... 21
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LIST OF FIGURES
1 General Location ofVHFS 2
2 General Locations of AREEs at VHFS ZZZZZZZZ"!ZZ" 3
3 SI and Ri Sampling Locations for AREE 9 - Vehicle Maintenance Area ZZZZi.'ZZZe
4 SI and RI Sampling Locations for AREE 11 - Former Sewage Treatment Plant '".". 7
5 SI and RI Sampling Locations for AREE 19 - Pistol Range "Z" 8
6 SI and RI Sampling Locations for AREE 21 - Sand Filter Beds !""Z""Z" i
LIST OF TABLES
ISMS Page
1 Cleanup Levels Established for Soils at the Four AREEs , 15
LIST OF ATTACHMENTS
Attachment 1 Proposed Plan
Attachment 2 Cleanup Level Development Documents
Attachment 3 Public Notice
in
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ABBREVIATIONS AND ACRONYMS
ARAR applicable or relevant and appropriate requirement
AREE Area Requiring Environmental Evaluation
bgs below ground surface
BRA Baseline Risk Assessment
BRAC Base Realignment and Closure
CECOM Communications-Electronics Command
CERCLA Comprehensive Environmental Response, Compensation, and Liability Act
CERFA Community Environmental Response Facilitation Act
DD Decision Document
EEQ environmental effects quotient
ENPA Enhanced Preliminary Assessment
ERA Ecological Risk Assessment
FS Feasibility Study
ft feet
HHRA Human Health Risk Assessment
HI Hazard Index
HQ Hazard Quotient
ICF KE ICF Kaiser Engineers, Inc.
IEUBK Integrated Exposure Uptake Biokinetic
MSL mean sea level
NCR National Oil and Hazardous Substances Pollution Contingency Plan
PAH polynuclear aromatic hydrocarbon
ppm parts per million
RBC risk-based concentration
Rl Remedial Investigation
SAIC Science Applications International Corporation
SARA Superfund Amendments and Reauthorization Act
SI Site Inspection
STP sewage treatment plant
TPH total petroleum hydrocarbon
TRV toxicity reference value
USAEC U.S. Army Environmental Center
USEPA U.S. Environmental Protection Agency
UST underground storage tank
VAC Virginia Administrative Code
VDEQ Virginia Department of Environmental Quality
VHFS Vint Hill Farms Station
IV
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DECLARATION FOR THE DECISION DOCUMENT
REMEDIAL ALTERNATIVE SELECTION
Site Name and Location
Areas Requiring Environmental Evaluation (AREEs) 9,11,19, and 21
Vint Hill Farms Station
Warrenton, Virginia
Statement of Basis and Purpose
This Decision Document (DD) presents a determination that no action is necessary to protect human health
and the environment for soil at AREE 21. In addition, this DD presents the selected remedial action for soil at
AREEs 9, 11, and 19 at Vint Hill Farms Station (VHFS), Warrenton, Virginia, chosen in accordance with the
Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA), as amended
by the Superfund Amendments and Reauthorization Act (SARA) of 1986 and, to the extent practicable, the
National Oil and Hazardous Substances Pollution Contingency Plan (NCP), 40 C.F.R. Part 300. This document
was prepared as a joint effort between the U.S. Army, the Virginia Department of Environmental Quality
(VDEQ), and the U.S. Environmental Protection Agency (USEPA). The no action and remedial action decisions
are based on documents contained in the Information Repository.
Assessment of the AREEs
Actual or threatened releases of hazardous substances from AREEs 9; 11, and 19, if not addressed by
implementing the remedial action selected in this DD, may present an imminent and substantial endangerment
to public health, welfare, or the environment.
Description of the Selected Remedy
The selected remedial action addresses the principal threat at AREEs 9, 11, and 19 by the excavation of
contaminated soil and off-site disposal at a permitted facility. No action is the selected remedy for AREE 21
since the established soil cleanup level is higher than the maximum detected contaminant concentration.
Statutory Determinations
The selected remedy (i.e., no action for AREE 21; and remedial action for AREEs 9,11, and 19) is protective
of human health and the environment, complies with Federal and state requirements that are legally applicable
or relevant and appropriate to the remedial action, and is cost-effective. This remedy utilizes permanent
solutions and alternative treatment technologies to the maximum extent practicable for AREEs 9,11, and 19.
i/ever, because treatment of the principal threat at AREEs 9,11, and 19 was not found to be practicable,
this remedy does not satisfy the statutory preference for treatment as a principal element of the remedy. A five-
year keview will ROTB>jnecessary for AREEs 9,11, 19, and 21 since the selected remedy will result in levels
of contaminatiob at orfofeiow risk-based cleanup levels.
JJ-CA^
ROBERT L. NABORS . V_ Date
Major General, USA
Commanding
U.S. Army Communications-Electronics Command
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DECISION SUMMARY
1.0 INTRODUCTION
The remedial action decision is based on the Phase I Reuse Area Remedial Investigation (Rl) Report (USAEC,
1998) which includes a Baseline Risk Assessment (BRA) documenting the risks from contamination in the soils
at Areas Requiring Environmental Evaluation (AREEs) 9,11,19, and 21. In the BRA, it was determined that
the soils at AREEs 11,19, and 21 pose unacceptable risks to human health and/or the environment. In addition,
total petroleum hydrocarbon (TPH) concentrations in soil at AREE 9 exceed the Virginia TPH soil action level
for underground storage tanks (USTs). Therefore, the soils at AREEs 9,11, and 19 require remedial action to
be protective of human health and the environment. However, upon establishing cleanup levels, it was
determined that no action is necessary to protect human health and the environment for soil at AREE 21
because the cleanup level is higher than the maximum detected contaminant concentration.
A feasibility study (FS), which develops and examines remedial action alternatives for a site, was
performed for AREEs 9,11, and 19 and presented in the Proposed Plan (see Attachment 1).
2.0 SITE BACKGROUND
Vint Hill Farms Station (VHFS) is part of the U.S. Army Communications - Electronics Command
(CECOM) and, while active, primarily functioned as an Army installation engaged in communications
intelligence. VHFS is located approximately 40 miles southwest of Washington, D.C., in Fauquier County,
Virginia, as shown on Figure 1. The installation occupies approximately 701 acres of land near the town of
Warrenton, Virginia. Approximately 150 acres of the installation are improved grounds in the southern portion
of the property used for industrial operations, administration buildings, and residential housing. Approximately
94 acres in the eastern portion of the property are mature hardwood forest, and the majority of the remaining
457 unimproved and semi-improved acres in the northern portion of the property are used for stationary and
mobile antenna operation sites.
VHFS was designated for closure in March, 1993, under the Base Realignment and Closure (BRAC)
Act. Pursuant to the decision to close the installation, an Enhanced Preliminary Assessment (ENPA) and a
Community Environmental Response Facilitation Act (CERFA) investigation of VHFS were conducted by
Science Applications International Corporation (SAIC) to assess the environmental condition of the installation.
The ENPA and CERFA investigations were completed in April and May, 1994, respectively. The ENPA identified
42 AREEs from the review of installation records, aerial photographs, installation personnel interviews, federal
and state regulatory records, and visual inspection. Of these 42 AREEs, 27 were recommended for further
investigation.
These 27 AREEs were investigated from September, 1994, to June, 1995, as part of the Site Inspection
(SI) conducted by SAIC. The objective of the SI was to determine the presence or absence of contamination
and the chemical nature of any detected contamination. The final SI Report (USAEC, 1996), which was
completed in June, 1996, identified 24 AREEs which required further investigation. In addition, four new AREEs
were identified during site reconnaissance to warrant further investigation subsequent to the SI. AREEs that
were determined to warrant further investigation and are located in the Phase I reuse area (shown on Figure
2) were investigated between April and June, 1996, as part of the Phase I reuse area Rl conducted by ICF
Kaiser Engineers, Inc. (ICF KE). The purposes of the Rl were to evaluate: 1) the nature and extent of
contamination; and 2) the level of risk posed to human health and the environment. The final Rl Report for the
Phase I reuse area (USAEC, 1998) was completed in April, 1998.
Four AREEs were identified in the Rl as having soil contamination which poses unacceptable human
health risks and/or significant adverse ecological effects:
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JEFFERSON
(W. Va.) f
HOWARD
MONTGOMERY
MARYLAND
ANNEARUNDEL
'
LOUDOUN
VIRGINIA ,V'
:HINGTOND.C..\ .
\>
••s-.
FAIRFAX "-'.-..-" '.••>•.''-.-
V-:.,'"- PRINCE GEORGES .'.
Vint Hill
Farms Station
' PRINCE WILLIAM
' . CHARLES.
FAUQUIER
STAFFORD
ST. MARrS
'- —. • . / KINGGEORGE. .'". Sf.X,fft.£:\ • .'•'•.'"""'. ' /l^
"x-'N,-i -••'•••'••/ •'^'•'•;^Jv't::^:''';>'v/-!- 'S*'v- '•
FIGURE 1
GENERAL LOCATION
OF VHFS
SCALE IN MILES
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o ioo axi
—^
SCALE IN fffl
LEGEND
ROAD
STREAM
PHASE I REUSE AREA
AREES:
gi VEHICLE MAINTENANCE AREA
FORMER SEWAGE TREATMENT PLANT
PISTOL RANGE
SAND FILTER BEDS
FIGURE 2
GENERAL LOCATIONS
OF AREEs AT VHFS
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• AREE 9 - Vehicle Maintenance Area;
• AREE 11 - Former Sewage Treatment Plant;
• AREE 19 - Pistol Range; and
• AREE 21 - Sand Filter beds.
The locations of these AREEs are shown on Figure 2.
3.0 SITE CHARACTERISTICS
3.1 Site topography
3.2 Adjacent Land Use
3.3 Surface Water Hydrology ^.
3.4 Qeology/Hydrogeology
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4.0 SITE HISTORY AND INVESTIGATION FINDINGS
^nHaJJL? f0r,thf eSU-L ARSES Was conducted to evaluate the n^ure and extent of contamination
associated with past site activities. Environmental samples collected and analyzed during the Rl were used in
conjunction with the results from the SI to assess the condition of each of the AREEs The environment^
rned.a mvesbgated included surface soil (0 to 2 ft below ground surface [bgs]), subsurface soil (2 ft to
approximately 12 ft bgs), surface water, sediment, and groundwater. Analytical results were compared to
background concentrations and regulatory screening levels to determine if environmental media had been
adverse y impacted by site activities. A brief description of each of the four AREEs and the significant findings
•" 6 pnftsentedjn the followin9 Paragraphs. A detailed presentation of the samples 13d
" ^ PhaS6 ' ReUS6 *"* R' RePOft
an earthen bottom.
SUrfaCe S0i'' s"bsurface soil' sediment, surface water, and groundwater samples were collected at
38 show!?.on f'gure 3" TPH contamination, exceeding the Virginia TPH soil action level for USTs of
100 parts per million (ppm). is present in subsurface soil beneath the Military Motor Pool neutralization oil
(which has an earthen bottom). The highest TPH concentration (8,440 ppm) was detected at the base of the
neutralization pit. The TPH contamination extends to bedrock at approximately 8.5 ft bgs, and'decreases with
u 6 ptn .
4.2 AREE 1 1 - Former Sewage Treatment Plant
1 cu« tn ^E 1 VS the site °f the former Sewage Treatment Plant (STP). The former STP was active from
1948 to 1981, and was used to treat wastewaters from VHFS activities, including industrial wastewaters from
photographic, painting, laboratory, vehicle washing, and metal etching operations. The sludges from the
treatment process were dried on drying beds and stored in sludge piles. The locations of these areas are
snown on Figure 4.
Shallow and deep surface soil samples were collected in the vicinity of the drying beds and sludae
fof^ T If samples were collected downgradient of these areas. Polynuclear aromatic hydrocarbon
(PAH) contamination, exceeding residential soil Risk-based Concentrations (RBCs) established bv the U S
Enwonmental Protection Agency (USEPA) Region III for screening of analytical results, is present in the
surface soil in the drying bed area and the sludge pile area. Pesticide contamination, exceeding residential soil
RBCs is present in the surface soil in the drying bed area and the sludge pile area. Mercury contamination
exceeding the residential soil RBC, is present in the surface soil in the sludge pile area.
4.3 AREE 19 - Pistol Range
^ „= AREE 19' tne Pistol Ranse, has been in use since 1 961 for limited target practice using 22 32 38
and .45 caliber handguns. The firing fan is directed southward toward a horseshoe-shaped impact berm which
captures the bullets. The layout of the Pistol Range is shown on Figure 5. Spent ammunition was not
recovered, but shell casings were collected and returned to the fixed ammunition magazine
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WESTERN SOUTH
RUN TRIBUTARY
VEHICLE
MAINTENANCE
.3UILDING
.FENCE
.ROAD
.STREAM
.—^380-^. TOPOGRAPHIC CONTOUR (FT USL)
—0~- CAICH BAStN W/SANITARV StWER
* SI SURFACE WATER SAMPLE LOCATION
•• SI SOIL BOSING LOCATION
€>.... SI SEDIMENT SAMPLE LOCATION
• .,.,. Rl SURFACE SOIL SAMPLE LOCATION1
O '. Rl SOIL BORING LOCATION
^.... Rl GROUNOWATER MONITORING WELL
.... IMPACTED SOIL AREA (APPROXIMATE)
N
)00
SCALE IN FEET
FIGURE 3
SI AND Rl SAMPLING LOCATIONS '
FORAREE9 j
VEHICLE MAINTENANCE AREA i
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WESTERN SOUTH
RUN TRIBUTARY
APPROXIMATE LOCATION
OF FORMER SLUDGE PILES
APPROXIMATE LOCATION
OF FORMER SLUDGE
DRYING BEDS
APPROXIMATE
LOCATION OF /'
FORMER SEWAGE
TREATMENT PI/ANT
GROUNDWATE
FLOW
DIRECTIO
Rl SURFACE ~5m-"SAMPLES
fWSSfKj THROUGH RISS11-9) ARE
CO-CQQATtS^WITH THE Rl SOIL SORING
! -1 THROUGH RISB11-9)
NOTE: A SUBSURFACE SOIL SAMPLE WAS NOT COLLECTS
AT Rissii-io TXJE TO^REFUSAL AT o.s' BGS
BUILDING
.FENCE
ROAD
STREAM
380 TOPOGRAPHIC CONTOUR (FT MSL)
SI SURFACE SOIL SAMPLE LOCATION
O. Rl SOIL BORING LOCATION
GROUNDWATER MONITORING WELL
FIGURE 4
SI AND Rl SAMPLING LOCATIONS
FORAREE11 -FORMER
SEWAGE TREATMENT PLANT
IMPACTED SOIL AREA (APPROXIMATE)
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PISTOL RANGE
DRAINAGE
IMPACT BERM
19-001
SS-i9-001
'RIHSB19-5
RIKS819-6
IHSB19-3
RIHS819-4
SS-19-002
STERK,
TR3UTARY
NOTE: Rl SURFACE SOIL'.SAMPLES
(RISS19-1.2,i.5. AND 6)'.ARE CO-LOCATED
WITH THE Rl SOIL BORING'.
LOCATIONS (RISB19-1,2.3.5 AND 6).
LEGEND:
• Rl
O...
CXVVvVt
BUILDING
FENCE
VHrS BOUNDARY
PAVED ROAD
STREAM
TOPOGRAPHIC CONTOUR (FT USL)
.. SI SURFACE SOIL SAW=LE LOCATION
SI SEDIMENT SAMPLE LOCATION
SURFACE SOIL/SOIL BORING LOCATION
Rl HORIZONTAL SOIL BORING LOCATION
...IMPACTED SOIL AREA (APPROXIMATE)
SCALE IN FEET
RGURE5
SI AND Rl SAMPLING LOCATIONS
FORAREE19
PISTOL RANGE
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Surface soil, subsurface soil, and sediment samples were collected from the impact berm and
surrounding area. Lead contamination, exceeding USEPA's screening level of 400 ppm for lead in soil for
residential use, is confined to the surface soil of the impact berm. The highest concentrations of lead (up to
5 850 ppm) were detected within the first six inches of the impact berm. Lead concentrations in the samples
collected deeper into the impact berm were generally one to two orders of magnitude lower than those at the
surface and were all less than 400 ppm.
4.4 AREE 21 - Sand Filter Beds
The Sand Filter Beds (AREE 21) were used to filter ash wastewaters from the wet scrubber, which was
used for particulate control in the installation incinerator smokestack. The two beds, constructed with concrete
walls and an unlined bottom, utilized coarse sand and filter gravel to filter particulates from the wastewater.
An underdrain system in the gravel drained the effluent to a distribution box. The effluent then discharged
through a perforated pipe to an absorption field north of the Sand Filter Beds.
Surface soil samples were collected from the Sand Filter Beds and along the absorption field.
Groundwater samples were collected in the vicinity and downgradient of the Sand Filter Beds and absorption
field as shown on Figure 6. Dioxin/furan contamination, exceeding residential soil RBCs, is present in surface
soil near the Sand Filter Beds and along the absorption field.
5.0 SUMMARY OF SITE RISKS
A BRA was conducted as part of the Rl to assess the human health and ecological problems that could
result if the contamination at the AREEs was not remediated. The Human Health Risk Assessment (HHRA)
was prepared to evaluate the magnitude of potential adverse effects on human health associated with current
industrial/commercial and potential future residential exposures to site-related chemicals at the AREEs. The
Ecological Risk Assessment (ERA) was conducted to characterize the potential threats to ecological receptors
posed by contaminants at the AREEs.
The HHRA follows a four-step process:
. Selection of Chemicals of Potential Concern - identifies the contaminants of potential concern
based on their toxicity, frequency of occurrence, and concentration by comparing the maximum
concentrations of detected chemicals with RBCs which are health-protective chemical
concentrations that are back-calculated using toxicity criteria, a 1x10 target carcinogenic risk or
a 0.1 hazard quotient (HQ, defined below), and conservative exposure parameters;
. Exposure Assessment - identifies the potential pathways of exposure, and estimates the
concentrations of contaminants to which people may be exposed as well as the frequency and
duration of these exposures;
• Toxicitv Assessment - determines the toxic effects of the contaminants; and
. Risk Characterization - provides a quantitative assessment of the overall current and future risk
to.people from site contaminants based on the exposure and toxicity information.
The HHRA evaluated health effects which could result from exposure to soil, groundwater, surface
water and sediment contamination in the Phase I reuse area of VHFS. The HHRA evaluated potential nsks
to current workers who could be exposed to contaminants in surface soil, and to current trespassers who could
be exposed to contamination in surface soil, surface water, and sediment. In addition, the HHRA evaluated
potential risks to hypothetical future adult residents who could be exposed to contaminants in groundwater and
surface soil and to hypothetical future child residents who could be exposed to contaminants in groundwater,
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4ft
LEGEND;
BUILDING
.PAVED ROAD
FENCE
.S7REAU
,--M
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surface soil, surface water, and sediment. Potential risks to future excavation workers who could be exnosod
to contaminants in subsurface soil were also evaluated in the HHRA. Subsurface soil was only evaluated for
excavation workers and not residents since residents would be unlikely to be exposed to subsurface soil In
aaoition, the concentrations of contaminants currently present in subsurface soil would not be representative
of the concentrations that might be present if landscaping activities were to occur which would involve mixina
of subsurface soils with surface soil, clean topsoil,.and other soil amendments. Therefore it would not be
appropnate to evaluate risks to residents using available subsurface soil data.
Potential carcinogenic (cancer-related) effects and noncarcinogenic effects (including various impacts
on different organ systems, such as lungs, liver, etc.) were evaluated in the HHRA. Carcinogenic effects are
expressed as the probability that an individual will develop cancer from exposure to the contaminants from each
f *h ul » eva'ua*on of noncarcinogenic effects is based on the hazard index (HI), which is the summation
of the HQs for individual chemicals. The HQ is a comparison of chemical-specific chronic exposure doses wrth
the corresponding protective doses derived from health criteria. The USEPA recommends that remedial
actions may be warranted at sites where the carcinogenic risk to any person is greater than 1x10"4 or the HI is
S,ea«lnanf ;n nnn'?09,6"'0 ** °f 1*1Q meanS that there is a potential of one additional P«*>n in a
population of 10,000 developing cancer from exposure to contaminants at an AREE if the AREE is not
remediated. A HI greater than 1 indicates a potential for noncarcinogenic health effects if the AREE is not
remediated. •
The ERA also follows a four-step process:
• Problem Formulation - develops information that characterizes habitats and potentially exposed
species and identifies contaminants of concern, exposure pathways, and receptors;
• Exposure Assessment - estimates exposure point concentrations for selected indicator species;
* Ecotoxicoloqic Effects Assessment - identifies concentrations or doses of contaminants that are
protective of indicator species; and
• Risk Characterization - estimates potential adverse effects from exposure to contaminants based
on exposure and toxicity information.
The ERA evaluated ecological effects which could result from exposure to surface soil surface water
and sediment contamination in the Phase I reuse area of VHFS. The ERA evaluated potential adverse
ecological effects to terrestrial plants and terrestrial invertebrates (represented by earthworms) exposed to
contaminants in surface soil. In addition, potential adverse ecological effects to mammals (represented bv
shrews) and birds (represented by robins) through bioaccumulation in the food web and exposure to
contaminants in surface soil were evaluated. Potential adverse ecological effects to aquatic life from exposure
to contaminants in surface water and sediment were also evaluated in the ERA.
^ « The evaluation of significant potential adverse ecological effects is based on the Environmental Effects
Quotient (EEQ). The EEQ is the ratio of the estimated exposure concentrations/doses for the chemicals of
potential concern and the toxicity reference values (TRVs) for the ecological receptors. If the EEQ is greater
than 1, there is a potential for adverse ecological effects to occur. As the magnitude of the EEQ becomes
greater than 1, the potential for adverse ecological effects becomes more significant.
The results of the BRA for the four AREEs are presented in the following paragraphs. A detailed
presentation of the BRA can be found in the Phase I Reuse Area Rl Report (USAEC, 1998) available in the
Information Repository.
11
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5.1 AREE 9 -Vehicle Maintenance Area
The BRA determined that site-related contamination at AREE 9 does not pose an unacceptable human
health risk or significant potential adverse ecological effects under either current industrial/commercial or
potenfial future residential land-use conditions. In fact, since all the chemicals of potential concern in surface
soil identified for AREE 9 in the HHRA are naturally-occurring metals that were statistically determined to be
within background concentrations, the estimated upper-bound excess lifetime cancer risks and noncarcinogenic
risks for site-related contaminants are less than 1x10'6 and a HI of 0.1. respectively. However, risks associated
with exposures to TPH could not be assessed in the BRA because this analytical parameter represents a
mixture of chemical constituents. Since TPH measurements give no indication of the chemical constituents
• 'present or their respective concentrations, they cannot be used to predict risks. Although risks associated with
TPH cannot be estimated, TPH contamination in subsurface soil beneath the Military Motor Pool neutralization
pit is recommended for remediation because TPH concentrations exceed the Virginia TPH soil action level for
USTs. The impacted area is approximately 3 ft x 3 ft, extending from the base of the neutralization pit at 4 ft bgs
to bedrock at 8.5 ft bgs.
5.2 AREE 11 - Former Sewage Treatment Plant
The HHRA concluded that, under current industrial/commercial land-use conditions, the risks to
workers are unacceptable for exposure to site-related contaminants in surface soil at AREE 11. Under potential
future residential land-use conditions, assuming that AREE 11 is not remediated, the risks to potential adult and
child residents are also unacceptable for exposure to site-related contaminants in surface soil. Discounting
naturally-occurring metals that were statistically determined to be within background concentrations, the highest
estimated upper-bound excess lifetime cancer risk is for adult residents exposed to site-related contaminants
in surface soil by dermal contact; this risk is 3x10"4 (i.e.. three in 10,000 residents may develop cancer caused
by contaminants in the AREE 11 surface soil). Discounting naturally-occurring metals that were statistically
determined to.be within background concentrations, the highest noncarcinogenic risk is for child residents
exposed to site-related contaminants in surface soil by incidental ingestion and dermal contact; the HI is
estimated to be 10 for each of these routes of exposure. The organ systems impacted by noncarcinogenic
contaminants at AREE 11 are the liver, kidney, blood, and gastrointestinal tract. The unacceptable human
health risks result primarily from chlordane (a pesticide) and mercury. Although the concentrations of PAHs
(specifically benzo[a]pyrene and dibenz[a,h]anthracene) at AREE 11 contribute to the unacceptable risks posed
by incidental ingestion exposure to contaminants in surface soil, they do not drive the unacceptable risks. The
highest estimated upper-bound excess lifetime cancer risk for a PAH is 7x10"6 (seven in 1,000,000 people) for
potential future child residents from incidental ingestion exposure to benzo(a)pyrene.
The ERA determined that contaminants in surface soil at AREE 11 pose significant potential adverse
ecological effects. The significant potential adverse ecological effects result primarily from DDT (a pesticide).
mercury, and silver. Mercury results in significant potential adverse ecological effects for terrestrial plants,
terrestrial invertebrates, robins, and shrews, with the greatest potential adverse ecological effects occurring to
robins (EEQ of 573). Silver and DDT result in significant potential adverse ecological effects to terrestrial plants
(EEQ of 60) and robins (EEQ of 51), respectively.
The most significant contamination is in the sludge pile area, which is recommended for remediation.
The impacted area has dimensions of 45 ft in diameter and 0.5 ft deep, with contamination extending to 1.5 ft
bgs in an isolated location near the center of the sludge pile area. The drying bed area, which has dimensions
of 25 ft x 40 ft x 1.5 ft deep, is less contaminated. One isolated surface soil location in the drying bed area
(sample location 887! 1-004 as shown on Figure 4) is recommended for remediation.
5.3 AREE 19 - Pistol Range
The HHRA concluded that, under both current industrial/commercial and potential future residential
land-use conditions, the risks to workers, trespassers, adult residents, and excavation workers are acceptable
12
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for exposure to site-related contaminants in soil at AREE 19. However, the risks to potential
res.der.ts are unacceptable for exposure to site-related contaminants in soi at AREE
Draining metals that were statistically determined to be within background co
estimated upper-bound excess lifetime cancer risk (3X10'5) is for potential future child
related I contam.nants in surface soil by incidental ingestion, while the highest noncarcinogenicSk (HI =
£± lrer± eXP°Sed t0 Site-related contaminante in surface s°" ^ incidental ingestion. The organ system
impacted by the noncarcmogenic contaminants at AREE 1 9 is the vascular system. The unacceptable human
health risks result pnmanly from antimony and arsenic which are found in conjunction with the lead
cont3min3tion.
The human health risks associated with exposure to lead in surface soil at AREE 1 9 were evaluated
using the Integrated Exposure Uptake Biokinetic (IEUBK) Model recommended by USEPA for evaluating fead
exposures for young children in residential settings. The IEUBK Model calculates blood lead levels* wn7ch result
from exposures to lead which may then be compared to blood lead levels of toxicological slgnmcance fo
Ue f°r AREE 19 predicted a 9eometric mean bl^d lead ?eve
of9uaM a eve
or 9.b ug/dL, wrth 42.7 percent of the population exceeding the level of concern (10 uq/dL) The USEPA
currently finds 5 percent of the population exceeding the level of concern as acceptable. Therefore, the IEUBK
model results indicate that ,f AREE 1 9 was developed for residential use in the future, the lead concentrations
in the surface soil may be a potential problem for young children. luauons
, • T,he«EF^ determined that !ead in surface soil at AREE 19 poses a significant potential adverse
ecological effect for terrestrial plants (EEQ of 11 7). Averse
The lead contamination in the impact berm surface soil is recommended for remediation The
approximate dimensions of the impacted area are 100 ft x 15 ft high x 2 ft deep. mea.aiion. ne
5.4 AREE 21 - Sand Filter Beds
The HHRA concluded that, under both current industrial/commercial and potential future residential
land-use conditions the nsks to workers, trespassers, residents, and excavation works are acceptable for
±PrnS0f« « s*9^e'ated. contaminants in surface soil at AREE 21 . Discounting naturally-occurring metals that
were statistically determined to be wrthin background concentrations, the highest estimated upper-bound excel
hfetime cancer nsk (9x1 (£ is for adult residents exposed to site-related contaminants in surface soil by dS
absorption, and the h.ghest noncarcinogenic risk (HI = 0.2) is for child residents exposed to site-related
contaminants in surface soil by incidental ingestion.
, • T,he«ER^ d!t,ermined that contaminants in surface soil at AREE 21 pose significant potential adverse
ecological effects The significant potential adverse ecological effects result primarily from 2,3,7 8-TCDF (a
ruran). 2,3.7,8-TCDF results in significant potential adverse ecological effects for robins (EEQ of 38).
in tho « H . of concern, 2,3,7,8-TCDF, was detected in the absorption field area but not
in the Sand Filter Beds themselves. Surface soil along the absorption field is recommended for possible
remediation pending establishment of soil cleanup levels. The approximate dimensions of the impacted soil
area are 375 ft x 3 ft x 3 ft deep.
6.0 REMEDIAL ACTION OBJECTIVES
Remedial action objectives are specific goals to protect human health and the environment The
remedial action objective for the four AREEs is to minimize the potential for contaminated soil to pose
unacceptable nsks to human or ecological receptors.
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7.0 CLEANUP LEVELS ESTABLISHED FOR THE SELECTED ALTERNATIVE
USEPA has established soil cleanup levels for the contaminants that contribute to the unacceptable
risk determination at each of the four AREEs. The soil cleanup levels are presented in Table 1. The soil
cleanup level for AREE 9 is based on the Virginia TPH soil action level for USTs of 100 ppm. In general,
USEPA established the soil cleanup levels for AREE 11 based on either a 1x10 (one in 1,000,000 people)
excess lifetime cancer risk for carcinogens1 or a hazard quotient of 1 for noncarcinogens, whichever was more
stringent, for the potential future residential use scenario. However, the soil cleanup levels for DDT, mercury.
and silver at AREE 11 are based on concentrations which are protective of ecological receptors. The soil
cleanup level fo- AREE 19 is based on a level recommended for the protection of ecological receptors by the
U.S. Fish and Wildlife Service. The soil cleanup level for AREE 21 is based on concentrations which are
protective of ecological receptors. The cleanup level for 2,3,7,8-TCDF (1.12x10" ppm) is higher than the
maximum detected concentration at AREE 21 of 8.71x10"6 ppm; therefore, no action is required at AREE 21
8.0 SUMMARY OF REMEDIAL ALTERNATIVES
Two remedial alternatives were evaluated to address soil contamination at AREEs 9,11, and 19. As
discussed above, no action is required for AREE 21 because the cleanup level is higher than the maximum
detected contaminant concentration. The range of remedial alternatives considered was limited by the nature
and extent of the contamination. Since the amount of soil requiring remediation is relatively small (less than 300
cubic yards combined), it was not practical to consider active treatment or containment options in terms of cost-
effectiveness and implementability. The following remedial alternatives were evaluated:
• Alternative 1 - No Action; and
• ' Alternative 2 - Soil Removal.
8.1 Alternative 1 - No Action
The National Oil and Hazardous Substances Pollution Contingency Plan (NCP) and the
Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), as amended by the
Superfund Amendments and Reauthorization Act (SARA), require that a No Action alternative be considered
as a baseline for comparison to other alternatives. No action would be taken to address site contamination
under this alternative. In accordance with Section 121 of CERCLA, each AREE would be reviewed at least
once every five years to re-evaluate site conditions and to determine the need for remedial action to protect
human health and the environment.
6.2 Alternative 2 - Soil Removal
Under this alternative, all contaminated soil exceeding the established cleanup levels wouid be
.excavated, transported off site by truck, and disposed using a combination of permitted off-site hazardous
waste, construction debris, and/or municipal landfills, as appropriate based on analytical results. Less than 300
cubic yards of impacted soil would be excavated as part of this alternative, followed by confirmation sampling
to assure adequate removal of all soil exceeding the cleanup levels. Upon completion of the soil excavation,
disturbed areas would be backfilled, regraded, and either vegetatively stabilized or paved (AREE 9).The five-
year review does not apply to this alternative because hazardous substances above risk-based cleanup levels
would not remain on site.
•5
1 The soil cleanup levels for AREE 11 presented in the Proposed Plan (Attachment 1) were based on a 1X10'
(one in 100,000 people) excess lifetime cancer risk for carcinogens. The basis for the soil cleanup levels was
made more stringent per the request of USEPA.
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Table 1
Cleanup Levels Established for Soils at the Four AREEs
Constituents
Cleanup Levels (ppm)
AREE 9 - VEHICLE MAINTENANCE AREA
Total Petroleum Hydrocarbons
100 (a)
AREE 1 1 - FORMER SEWAGE TREATMENT PLANT
Aidrin (Human Health risk) (b)
Cadmium (Human Health risk) (b)
Chlordane (Human Health risk)
alpha-Chlordane (Human Health risk) (b)
gamma-Chlordane (Human Health risk) (b)
DDTr (Ecological risk)
Mercury (Human Health & Ecological risk)
Silver (Ecological risk)
0.038 (c)
39 (c)
0.49 (c)
0.49 (c)
0.49 (c)
0.26 (d)
0.29 (d)
20 (d)
AREE 19 - PISTOL RANGE
Lead (Human Health & Ecological risk)
200 (e)
AREE 21 - SAND FILTER BEDS
2,3,7,8-TCDF (Ecological risk)
1.12x10"'(d)
DDTr - Total concentration of ODD, DDE, and DDT
(a) Virginia total petroleum hydrocarbon soil action level for underground storage tanks.
(b) These compounds contribute to but do not drive unacceptable risk.
(c) Based on either a 1 x10"6 upper-bound excess lifetime cancer risk for carcinogens or a hazard quotient
of 1 for noncarcinogens, whichever is more stringent, for the potential future residential use scenario.
(d) Based on a concentration which is protective of ecological receptors (EEQ = 10).
(e) .Cleanup level for lead in surface soil recommended by the U.S. Fish and Wildlife Service for the
protection of ecological receptors. . •
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9.0 EVALUATION OF ALTERNATIVES
CERCLA requires a comparison of the alternatives using nine evaluation criteria: overall protection
of human health and the environment; compliance with applicable or relevant and appropriate requirements
(ARARs); long-term effectiveness and permanence; reduction of toxicity, mobility or volume through treatment;
short-term effectiveness; implementability; cost; and regulator and community acceptance. The first two criteria
are considered by USEPAto be threshold criteria which must be met by each alternative. The nine evaluation
criteria are described below.
• Overall protection of human health and the environment addresses whether or not a remedy
provides adequate protection and describes how risks posed through each pathway are
eliminated, reduced, or controlled through treatment, engineering controls, or institutional
controls.
• Compliance with ARARs addresses whether or not a remedy will meet all of the applicable
or relevant and appropriate requirements of other federal and state environmental statutes
and requirements or provides grounds for invoking a waiver.
• Long-term effectiveness and permanence refers to the ability of a remedy to maintain reliable
protection of human health over time, once cleanup goals have been met.
• Reduction of toxicity. mobility, or volume through treatment is the anticipated performance of
the treatment technologies a remedy may employ.
• Short-term effectiveness addresses the period of time needed to achieve protection and any
adverse impacts on human health and the environment that may be posed during the
construction and implementation period until cleanup goals are achieved.
• Implementabilitv is the technical and administrative feasibility of a remedy, including the
availability of materials and services needed to implement a particular option.
• Cost includes estimated capital and operation and maintenance costs, and net present worth
costs.
• Regulator acceptance indicates whether, based on their review of the Rl and Proposed Plan,
the regulators (the Virginia Department of Environmental Quality fVDEQ] and USEPA) concur,
oppose, or have no comment on the selected alternative.
• Community acceptance is assessed in the Responsiveness Summary which summarizes the
public comments received on the Rl and the Proposed Plan.
The comparative analysis of the alternatives was conducted based upon these evaluation criteria, and is
described below.
9.1 Overall Protection of Human Health and the Environment
The no action alternative (Alternative 1) is not protective of human health or the environment because
the risks to potential future residents and the potential adverse effects to ecological receptors remain
unchanged, which is unacceptable. Therefore, the no action alternative was eliminated from further
consideration and will not be discussed further.
Alternative 2 provides adequate protection of human health and the environment by removing
contaminated soil, thereby eliminating the potential for exposure.
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9.2 Compliance with ARARs
-etakr . A!iei"Pative 2 has been designed to achieve or comply with ARARs. This alternative will satisfy the
estabjshed cleanup levels since all soil that is contaminated above applicable cleanup levels ^be ^removed
In , addition. the removal and disposition of contaminated soil during implementation of Active 2
don
o ve w
done ,n accordance wrth federal and Virginia solid and hazardous waste regulations Durinq soil excavation
the Regulatoons of the Virginia Air Pollution Control Board may apply. Ambient ai? condiS • woufd be
monitored during excavation activities to assure acceptable air quality. As necessary based on the amSent afr
monitoring, water sprays would be used to keep dust levels down. ambient alr
9.3 Long-term Effectiveness and Permanence
Alternative 2 would provide for the permanent removal of contaminated soil to a permitted off-site
locabon des.gned to prevent contaminant migration and exposures to human and ecologicafreTeSors
9.4 Reduction of Toxicity, Mobility, or Volume Through Treatment
Alternative 2 provides reduction of contamination at the AREEs by removing contaminated soil The
T ^r0"!* minated soil wou|d not be affected by this alternative; howev^Mhe mobilitj of
redUCed because the °™* disP°<*' facilities used wou.d be designed to prevent
Because treatment of the contaminated soil at the AREEs was not found to be practicable due to the
StatUt°^ Preference for ^atment as a principal
9.5 Short-term Effectiveness
Alternative 2 is considered to be effective in the short term because the volume of soil to be excavated
-s relatve y small and would result in limited negative impacts to human health oTlhe envi onmen
asPn°6S^H0pWO f'5 and adJ3Cent reSldentS W°Uld be C0ntrolled durin9 excavation activites by
as needed. Prior to excavation operations, temporary erosion control structures would be installed to prevent
0 8 *™ ^ ^^ erOSi°n and mwement of soil from
areas * a
nLriS ?lthough truc,k traffic would be increased during implementation of Alternative 2, the implementation
penod (approximately one month) is short and the number of trucks per day would be less than 20
9.6 Implementability
implementable' Licensed ^°«™ and permitted disposa,
9.7 Cost
The cost to implement Alternative 2 is estimated at $360,000.
9.8 Regulator Acceptance
VDEQ and USEPA concur with the selected remedy.
17
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9.9 Community Acceptance
A public meeting on the Proposed Plan was held on September 18, 1997, in Warrenton Virginia
Comments received during the public meeting and the public comment period are referenced in the '
Responsiveness Summary (Section 12 of this DD).
10.0 SELECTED REMEDY AND STATUTORY DETERMINATIONS
10.1 Selected Remedy
Following review and consideration of the information in the Information Repository, requirements of
CERCLA and the NCP, and the review of public comments on the Proposed Plan, the US Army in
coordination with VDEQ and USEPA, has selected Alternative 2, Soil Removal, as the remedy for the
contaminated soil at AREEs 9,11, and 19. No action fe the selected remedy for the soil at AREE 21 because
the cleanup level is higher than the maximum detected contaminant concentration.
Under the selected remedy for AREEs 9,11, and 19, all contaminated soil exceeding the established
cleanup levels would be excavated, transported off site by truck, and disposed using a combination of permitted
off-site hazardous waste, construction debris, and/or municipal landfills, as appropriate based on analytical
results. Less than 300 cubic yards of impacted soil would be excavated as part of this alternative, followed by
confirmation sampling to assure adequate removal of all soil exceeding the cleanup levels (refer to Table 1)
Upon completion of the soil excavation, disturbed areas would be backfilled, regraded. and either vegetativelv
stabilized or paved (AREE 9).
The estimated cost to implement this alternative is $360,000, and the on-site activities would require
approximately one month to complete. Jttk
10.2 Statutory Determinations '
Under CERCLA Section 121, selected remedies must be protective of human health and the
environment, must comply with ARARs (unless a statutory waiver is justified), must be cost-effective.'and must
utilize permanent solutions and alternative treatment technologies or resource recovery technoDogies to the
maximum extent practicable. In addition, CERCLA includes a preference for remedies that employ treatment
that permanently and significantly reduces the volume, toxicity, or mobility of hazardous waste as their principal
element The following sections discuss the remedy in light of these statutory requirements.
10-2-1 Protection of Human Health and the Environment
The selected remedy (i.e.. no action for AREE 21; and remedial action for AREEs 9,11, and 19) would
protect human health arid the environment All contaminated soil exceeding the established cleanup levels will
be removed and disposed of in permitted, off-site facilities. The cleanup levels listed in Table 1 were developed
to be protective of human health and the environment
• .Short-term risks would be present as a result of dust exposure to workers and adjacent residents, soil
erosion and sedimentation during excavation activities, and transport of contaminated soil off site. These risks
would be acceptable as a result of control measures which would be implemented during the remedial action.
These control measures include use of water sprays during excavation operations to control dust, and use of
silt fences and other erosion control techniques to control erosion and soil movement from contaminated areas.
The increase in truck traffic would be minimal, with the addition of less than 20 trucks per day over the course
of approximately one month.
18
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10-2-2 Compliance with ARARs
The selected remedy will be in full compliance with ARARs:
f* 2°'80'10 flt'aasu: Wginia Solid Waste Management Regulations
' S'Udge °r ^ °ther S°'id Waste must be done in compliance with ^e
9 VAC 20-60-10 et seg^: Virginia Hazardous Waste Management Regulations - the disoosal of am,
hazardous waste must be done in compliance with the regulations; ™» disposal of any
' - §§SL: Wginia Erosion and Sedimentation Control Regulations - an erosion and
bl o?enDrdChTlieS Wfth the minimUm deSign and 'Cementatio
be prepared before engaging in any land disturbing activity;
fmAC f"10"10 ?r°U9h 9 VAC 5-8°-35°: Regulations of the Virginia Air Pollution Control Board -
ambient air mon.tor.ng will be used to determine the need for water sprays to control dust qeneraten
in order to comply with ambient air quality standards for paniculate matter generation
10.2.3 Cost-Effectiveness
6StabllShed SON C'eanUP ieVel' The entire remed* «"' be achieved *" aSSS
10-2'4 "t'l'zation of Permanent Solutions and Alternative Treatment Teehnnlnnioc »r
Resource Recovery Technologies to the Maximum Extent PrartScable -
th» hoctlhf selected rem,fdy utilizes Permanent solutions to the maximum extent practicable while providina
^ nS hn?6 amon9.tthe other evaluation criteria. It achieves the best balance of tradeoffe w5h respec to
the primary balancing crrtena of long-term effectiveness and permanence; reduction of taddh mS ^ and
^
a relatively short time frame needed for design development. There is minimal risk to the
communrty during the implementation of the selected remedy, and the slight risks to the enTor?menfcan be
reduced by implementing standard procedures, such as erosion and sedimentation controls
10-2-5 Preference for Treatment as a Principal Element
r*m0H Jecause: treatm!"t of the Principal threat at AREEs 9, 11 , and 1 9 was not found to the practicable this
remedy does not satisfy the statutory preference for treatment as a principal element of the remedy
1 1 .0 HIGHLIGHTS OF COMMUNITY PARTICIPATION
i Proposed Plan for AREEs 9,11,19. and 21 was released to the public on September
« H • , Tie. '' Tnis document was made available for public review in th
following location:
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Fauquier County Library
Warrenton Branch - Reference Section
1 1 Winchester Street, Warrenton, VA
(540) 347-8750
Monday- Wednesday: 10:00 a.m. to 9:00 p.m.
Thursday- Saturday: 9:00 a.m. to 5:00 p.m.
Sunday: 1 :00 p.m. to 5:00 p.m.
flhecnotic? °f availability of the Proposed Plan (see Attachment 3) was published in The
the Fauqu.erTimes-Demonmt. and the Manassas Journa. M^^JL during the week
foe U.S. Army will publ,sh a notice of availability of this DD in Ihe_Fauguier_c£^ '
Dgmocrat. and the Manassas Journal Mp^ngpr. and place the DD in tte InfonSSn
12.0 RESPONSIVENESS SUMMARY
questions and receive comments. At the public meetina
The Responsiveness Summary is divided into the following sections:
dates of the publb """""^ ^^ and location and
• Comments raised during the public meeting on September 18,1 997;
• Public meeting attendance roster; and
* Restoration Advisory Board Members.
document "^ "•" mumi »'*• u-s-
12.1 Selected Newspaper Notices
or September 8. 1 997. This public notice is provided in AttachmemT -
12.2 Comments Raised During the Public Meeting on September 18, 1997
le public
CONCERNED CITIZEN: Is there any risk that the $360,000 of required funding may not being available?
20 -
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ARMY RESPONSE: No, the project is fully funded.
CONCERNED CITIZEN: For AREE 21, how can the cleanup level be higher than the maximum detected
concentraton? Are there still ecological risks to wildlife? maximum aetected
ARMY RESPONSE: Based on the BRA, it was determined that there was unacceptable ecological risks nosed
n 3t ARE^ ?1 ' H°WeVer' the BRA USes «*™**» assumptions such 55 aSr^K
^rT^ *"" ""*? h contaminated at «* maximum detected contaminant concentration
T, S 'S an unreallstlc ^sumption because AREE 21 is only a thin strip of land which
V6ryfSmal P«~ntaae of a robin's foraging ground. When the size of AREE 21 is conSwdh
,nn, t * Ao«CLe«a"Up l6Vel' a Cleanup level greater than the maximum detected contaminant
concentration at AREE 21 ,s calculated. The BRA uses conservative assumptions so that sites that mayTeed
to be remediated are not overlooked; while the cleanup level is a level that brings the site into acceptable risk
limits under reahstic conditions. The need for remediation at AREE 21 was ultimately based on a risk
management decision using the more realistic risk-based cleanup level. Since a robin would not just consume
earthworms from the small strip of land contaminated at AREE 21 , the risk posed by AREE 21 is acceptable
CONCERNED CITIZEN: Once these sites are cleaned up, will sampling be conducted to ensure that the sites
3T6 S3T6 f •
2ISIL2^(JJISE: YeS*' confi';mation samP"n9 will be conducted to ensure that the cleanup levels are
achieved, and then a post-remediation risk assessment will be conducted to ensure that the risk posed by the
residual contamination is acceptable. oouuyuie
CONCERNED CITIZEN: Would any restrictions be placed on AREE 21 that it not be disturbed? AREE 21 is
located in the area currently designated for the golf course. Could the soil in that area be moved around to
accommodate desired terrain changes?
ARMY RESPONSE: There would be no restrictions on the future use of AREE 21 .
SSU^H^S ?LTIZELN: W!!at is the name of the faciiity and rts location wnere the contaminated soil will be
disposed? Will it be a hazardous waste facility? Will it be hauled to the local landfill?
ARMY RESPONSE: The disposal facility has not been determined yet, but acceptably permitted facilities will
be used. If warranted based on waste characterization sampling, a permitted hazardous waste disposal facility
w I! be used G.ven the levels of contamination at these AREEs, the excavated soil even if non-hazardous will
probably not be acceptable for disposal at the local landfill; however, that determination will be made once the
waste characterization sampling results are received and reviewed. The waste will have to satisfy the selected
landfill's permit requirements before it can be disposed therein.
12.3 Public Meeting Attendance Roster
>», publitcumeetin9 was neld on September 1 8, 1 997, at the Warrenton Middle School. The members
of the communrty that attended the public meeting included Owen Bludau, Debra Reedy, and Dean Eckelberry.
12.4 Restoration Advisory Board Members
1 . Debra Reedy, Community Co-Chair
2. Richard Reisch, U.S. Army Co-Chair
3. Dean Eckelberry
4. John Mayhugh
5. Jeff Lippincott
6. Owen Bludau
21 .
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7. TimTarr
8. Norn's Goff
9. Erich Meding
10. Kevin Bell
11. Mark Stevens
12. Nancy Inger
13. Joanne Smith
14. Henry Ross
15. Steve Mihalko
16. Robert Stroud
17. Steve Maddox
18. William Downey
19. GinaTyo
20. JoePhelan
21. Gary Clare
22. MikeMolloy
23. Denny Adams
24. JoeWiltse
25. Bob Root
26. Georgia Herbert
27. Robert Kube
28. Kimberly Davis
29. George Rosenberger
30. Adrienne Garreau
31. Susan Dove
32. James Tucker
33. John Williams
13.0 REFERENCES
22
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ATTACHMENT 1
PROPOSED PLAN
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Proposed Plan
AREEs 9, 11, 19, and 21
Vint Hill Farms Station, Virginia
September 1997
INTRODUCTION
The U.S. Army has identified a preferred alternative to address contaminated soil at selected Areas
Requiring Environmental Evaluation (AREEs) located on Vint Hill Farms Station (VHFS). The major
characteristics of the U.S. Army's preferred alternative (Alternative 2 in this Proposed Plan) include
excavation of contaminated soil and off-site disposal at a permitted facility.
This Proposed Plan is based on site-related documents contained, in the VHFS Information Repository.
The Information Repository can provide you with important information about the site and the AREEs The
Information Repository is located at:
Fauquier County Library
Warrenton Branch - Reference Section
11 Winchester Street, Warrenton, VA
(540) 347-8750
Monday - Wednesday: 10:00 a.m. to 9:00 p.m.
Thursday - Saturday: 9:00 a.m. to 5:00 p.m.
Sunday: 1:00 p.m. to 5:00 p.m.
The U.S. Army needs your comments and suggestions. The U.S. Army, the U.S. Environmental Protection
Agency (USEPA) Region III. and the Virginia Department of Environmental Quality (VDEQ) encourage the
public to review and comment on both of the alternatives presented in the Proposed Plan. The public
comment period begins on September 11, 1997, and closes on October 10, 1997. Please send your
comments, postmarked no later than October 10. 1997. to:
Kevin Bell, Public Affairs Officer
Public Affairs Office (Bldg. 101)
Vint Hill Farms Station
Warrenton, VA 20187-5010
In addition, you are invited to a public meeting regarding the investigation and cleanup of contamination
at the AREEs. Representatives from the U.S. Army will report on cleanup alternatives considered and. the
U.S. Army's preferred alternative. The meeting is scheduled for:
Thursday, September 18, 1997 at 7:00 p.m.
Warrenton Middle School Auditorium
244 Waterloo Street, Warrenton, VA
The remedy described in this Proposed Plan is the U.S. Army's preferred alternative for the selected
AREEs. The U.S. Army may modify the preferred alternative or select another remedial alternative if public
comments or additional data indicate that such a change will result in a more appropriate remedial action.
The U.S. Army, in consultation with USEPA. and VDEQ, will make a remedy selection for the AREEs in a
Decision Document after the public comment period has ended and the comments and information
submitted during that time have been reviewed and considered.
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The U.S. Army is issuing this Proposed Plan as part of its public participation responsibilities under
Sections 113(k) and 117(a) of the Comprehensive Response, Compensation, and Liability Act (CERCLA).
as amended, commonly known as the "Superfund Program', and the National Environmental Policy Act
of 1969 (NEPA).
SITE BACKGROUND
VHFS is part of the U.S. Army Communications - Electronics Command (CECOM) and primarily functions
as an Army installation engaged in communications intelligence. VHFS is located approximately 40 miles
southwest of Washington, D.C., in Fauquier County, Virginia, as shown on Figure 1. The installation
occupies approximately 701 acres of land near the town of Warrenton, Virginia Approximately 150 acres
of the installation are improved grounds in the southern portion of the property used for industrial
operations, administration buildings, and residential housing. Approximately 94 acres on the eastern
portion of the property are mature hardwood forest, and the majority of the remaining 457 unimproved
and semi-improved acres in the northern portion of the property are used for stationary and mobile
antenna operation sites. The facility was designated for closure in March, 1993, under the Base
Realignment and Closure (BRAG) Act.
Pursuant to the decision to close the installation, an Enhanced Preliminary Assessment (ENPA) and a
Community Environmental Response Facilitation Act (CERFA) investigation of VHFS were conducted by
Science Applications International Corporation (SAIC) to assess the environmental condition of the
installation. The ENPA and CERFA investigations were completed in April and May, 1994, respectively.
The ENPA identified 42 AREEs from the review of installation records, aerial photographs, installation
personnel interviews, federal and state regulatory records, and visual inspection. Of these 42 AREEs, 27
were recommended for further investigation.
These 27 AREEs were investigated from September, 1994, to June, 1995, as part of the Site Inspection
(SI) conducted by SAIC. The objective of the SI was to determine the presence or absence of
contamination and the chemical nature of any detected contamination. The final SI Report, which was
completed in June, 1996, identified 24 AREEs which required further investigation. AREEs that were
determined under the SI to warrant further investigation and are located in the Phase I reuse area (shown
on Figure 2) were investigated between April and June, 1996, as part of the Phase I reuse area Remedial
Investigation (Rl) conducted by ICF Kaiser Engineers, Inc. (ICF KE). The purpose of the Rl was to
evaluate: 1) the nature and extent of contamination; and 2) the level of risk posed to human health and
the environment. The draft Rl Report for the Phase I reuse area was completed in April, 1997, and is
currently undergoing regulatory review.
Four AREEs were identified in the Rl as having soil contamination which poses unacceptable human
health risks and/or significant adverse ecological effects:
• AREE 9 - Vehicle Maintenance Area;
• AREE 11 - Former Sewage Treatment Plant;
• AREE.19 - Pistol Range; and
• AREE 21 - Sand Filter Beds.
The locations of these AREEs are shown on Figure 2.
RESULTS OF THE REMEDIAL INVESTIGATION
The Rl for these four AREEs was conducted to evaluate the nature and extent of contamination associated
with past site activities. Environmental samples collected and analyzed during the Rl were used in
conjunction with the results from the SI to assess the condition of each of the AREEs. The environmental
media investigated included surface soils (0 to 2 feet below ground surface), subsurface soils (2 feet to
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VIRGINIA
,-'" WASHINGTON D.C.\
FAIRFAX
Vint Hill
Farms Station
•--„'':, PRINCE GEORGES ,'
PRINCE WILLIAM
CALVERT
CHARLES
' FAUQUIER
•
.
/•i:^,:-t:v'r'7.V-
STAFFORD
ST. MARY'S
KING GEORGE
FIGURE 1
GENERAL LOCATION
OF VHFS
--' -N-
0'- 5 - 10
SCALE IN MILES
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LEGEND
/•"ROAD
.,-' STREAM
. I REUSE AREA
AREES:
(a\ VEHICLE MAINTENANCE AREA
fifl rORMER SEWAGE TREATMENT PI ANT
FIGURE 2
GENERAL LOCATIONS
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i
AREE 3 - Vehicle Maintenance Area
9 as" s^own'nn'nnf *? ?"' ^flment- surface water- a^ groundwater samples were collected at AREE
son aS .pl^f9 H T°tal Petroleum Hydrocarbon (TPH) contamination exceeding the Virgin a TPH
suh^Sl ?K under9round St°ra9e tanks (USTs) of 100 parts per million (ppm) is present in
NohP^TpJ0 ^ thS Mi"'tary Mot0r P°01 neutralization pit (which has an eaE bottom? The
highest TPH concentration (8,440 ppm) was detected at the base of the neutralization pT The TPH
contam.na.on extends to bedrock at approximately 8.5 feet be.ow ground surface and decreases wlh
AREE 11 . Former Sewage Treatment Plant
0'"16' SeWa9e Treatment Plant (STp). The former STP was active from 1948
aSte^6rS fr°m WFS aCtlVitieS' includin9 industrial wastewaters from
, vehicle washing, and metal etching operations. The sludges from the
nd St°red in Slud9* P»- The .ocations of these
S0" STPleS WSre CO"eCted in the vicinity of the dfVin9 be^ and sludge piles
m n» wereMcollected downgradient of these areas. Polynuclear aromatic hydrocarbon
m for c ' ""f*** «8ldenttal soil Risk-based Concentrations (RBCs) established by USEPA
area anS the SSS"? analytical resu.ts. is present in the surface and subsurface soil in the drying bed
*, .rflono H K 95 P 3rea- Pestlclde contamination, exceeding residential soil RBCs, is present in the
is ™ntSUrXCe S°rf" ln thS S'Udge P"e area MerCUfy c°ntamination, exceeding the resident soh
is present in the surface soil in the sludge pile area
AREE 19 - Pistol Range
!? ?!' haS been'''n USe Since 1961 for limited tar3et Practice using .22, .32, .38, and
^Tn The^'nQ fan is dk80ted southward toward a horseshoe-shaped mpact berm
h?f h fS- ^ 'ayOUt °f thS PiSt°' Range iS Shown on Fi9ure 5' SPe"t ammunition was
not recovered, but shell cas.ngs were collected and returned to the fixed ammunition magazine.
rL' OH' and S? lment SamplSS Were C0llected from the imPact berm and surrounding
S is cnnfinPd fn th "; exceedin? USEPA'S screening level of 400 ppm for lead in soil for residential
use is confined to the surface soil of the impact berm. The highest concentrations of lead (up to 5 850
SctedrLPt?ed f11" the ff ? SJX lnCheS °f the impact berm- Lead concentrations in theP samples
at h?^pP,nH ',MPaCt ,berm W6re 9enerally °ne to **" orders of magnitude lower than those
at the surface and were all less than 400 ppm.
-------
VEHICLE .
MAINTENANCE
.BUILDING
....FENCE
ROAD
...STREAM
„ TOPOGRAPHIC CONTOUR (FT MSI)
—0 .......CATCH BASIN W/SANITARY SEWER
9 S! "SURFACE WATER SAMPLE LOCATION
«• SI SOU BORING LOCATION
g>.,., SI SEDIMENT SAMPLE LOCATION
• .,.........R SURFACE SOIL SAMPLE LOCATION
O Rl SOU. BORING LOCATION
•£•,.... R! GROUNDWATER MONITORING WEU
*,... IMDACTcD SOIL AREA (APPROXIMATE}
N
(O)
1QC
SCALE IN FEET
FIGURES
SI AND Rl SAMPLING LOCATIONS
FOR AREE 9
VEHICLE MAINTENANCE AREA
-------
\ I (l RIS311-90\
\ RlSBI/1-
\ SS-%-002
GROUNOWATE
FLOW
OlRECTIOi
Rl SURFACE "5©1f"SAMPl£S
THROUGH RISS11-9) ARE
WITH THE Rl SOIL BORING
i -1 THROUGH Risen-9)
NOTE: A SUBSURFACE SOIL SAMPLE WAS NOT COLLECTE
AT RISS1 1-10 DUE KKREFUSAL AT 0.5' BGS
ROAO
STREAM
TOPOGRAPHIC CONTOUR (FT MSL)
SI SURFACE SOIL SAMPLE LOCATION
FIGURE 4
SI AND Rl SAMPLING LOCATIONS
FORAREE11 -FORMER
SEWAGE TREATMENT PLANT
O. Rl SOIL SORING LOCATION
GROUNOWATER MONITORING WELL
IMPACTED SOIL AREA (APPROXIMATE)
-------
PISTOL RANGE/'..
IMPACT 3ERM
33-19-001
SS-19-001
RIHS819-5
RIKSE19-5
HSB19-3
RIHS319-4
SS-19-002
RIHS319-2
WESTERN /SOUTH
TRIBUTARY
NOTE: fil SURFACe SOIL'.SAMPLES
(RISS19-1.2.3.5. AND 6) '.ARE CO-LOCATED
WITH THE Rl SOIL BORING;
LOCATIONS (RISBI9-1.2.3,5 AND 6).
LEGEND:
BUILDING
FENCE
VHFS BOUNDARY
PAVED ROAD
• •— STREAM
390 TOPOGRAPr-'C CONTOUR (FT MSL)
• SI SURFACE SO'. SAMPLE LOCATION
® 5l SEDIVENT SAMPLE LOCATION
• Rl SURFACE SOIL/SO!L 30RING LOCATION
O. .Rl HORIZONTAL SO:: SORING LOCATION
ESSSS5....IMPACTED SO!'. AREA (APPROXIMATE)
N
(o)
50 100
SCALE IN FEET
FIGURES
SI AND Rl SAMPLING LOCATIONS
FORAREE19
PISTOL RANGE
-------
AREE 21 - Sand Filter Beds
The Sand Fitter Beds (AREE 21) were used to filter ash wastewaters from the wet scrubber whirh
used for particulate control in the installation incinerator smokestack. The tweeds Constructed
concrete walls and an unlined bottom, utilized coarse sand and fllt
ten
then
" T"" " ^ ^^ drained the 6ffluent tO a r
through a perforated pipe to an absorption field north of the Sand Filter Beds
C°"eCted fr°m the Sand Filter Beds and al°"9 the absorption field
abn f ,n H C°"eCted in the Vicinity and downgradient of the Sand Firte Beds and
absorPt,on field as shown on Figure 6. Dioxin/furan contamination, exceeding residential soil RBCs is
present in surface so.l near the Sand Filter Beds and along the absorption field. '
HUMAN HEALTH AND ECOLOGICAL RISK ASSESSMENT
A Baseline Risk Assessment (BRA) was conducted as part of the Rl to assess the potential human health
SumS°H9Tth £Tf mS that C°Uld reSUlt tf the contamination at the AREEs was not e%ed^ed The
rt^f? H R'lk Afsessment (HHRA) was prepared to evaluate the .magnitude of potential adverse
of the nmn ^n ***** associated with current and potential future (assuming iBsldeSJSSeJSSJ
of the property) exposures to site-related chemicals at the AREEs. The Ecological Risk Assessment^ v
was conducted to characterize the potentia, threats to ecological receptors posei by conta "nants ft the
The HHRA follows a four-step process:
Selection of Chemicals of Potential Concern - identifies the contaminants of potential
concern based on their toxicfty, frequency of occurrence, and concentration bv
comparing the maximum concentrations of detected chemicals with RBCs which are
health-protective chemical concentrations that are back-calculated using toxicrty criteria
a 1x10 target carcinogenic risk or a 0.1 hazard quotient (defined below) and
conservative exposure parameters;
Exposure Assessment - identifies the potential pathways of exposure, and estimates the
concentrations of contaminants to which people may be exposed as well as the
frequency and duration of these exposures;
Toxicrty Assessment - determines the toxic effects of the contaminants; and
Risk Characterization - provides a quantitative assessment of the overall current and
future risk to people from site contaminants based on the exposure and toxicitv
information. ,
The HHRA evaluated health effects which could result from exposure to soil, groundwater, surface water
anc I sediment contamination in the Phase I reuse-area of VHFS. The HHRA evaluated potential risks to
current workers who could be exposed to contaminants in surface soil, and to current trespassers who
could be exposed to contaminants in surface soil, sediment, and surface water. In addition, the HHRA
evaluated potential risks to hypothetical future adult and child residents who could be exposed to
contaminants in surface soil, groundwater, surface water, and sediment. Potential risks to future
excavat.on workers who could be exposed to contaminants in subsurface soil were also evaluated in the
HHRA.
-------
GROUXDWATER
FLOW
DIRECTION
....BUILDING
PAVED ROAD
FENCE
STREAM
TOPOGRAPHIC CONTOUR (FT USL)
PERFORATED PIPE
SITE BOUNDARY
,SI SURFACE SOL SAMPLE LOCATION
GSOUNDWATER MONITORING WELL
N
®. SI CROUKOWATER PUSH SAMPLE LOCATION
•©• SI DRY PROBE LOCATION
•..,. .JK SyRFACE SOS. SAUPLE LOCATION
SSSSS...tW?ACTED SOIt AREA (APPROXIMATE)
0 S3 100 150
SCALE IN FEET
RGURE 6
SI AND Rl SAMPLING LOCATIOIMS
FOR AREE 21
SAND FILTER BEDS
10
-------
potential for noncarcmogenic health effects if the AREE is not remediated. indicates a
The ERA also follows a four-step process:
^'eor"Form'."arinn ' develops information that characterizes habitats and potentially
**e™S contanriinants of c°ncern, exposure pathways and
' estimates exposure point 'concentrations for selected indicator
EcotoxicoloQic Effects Assessment - identifies concentrations or doses of contaminants
that are protective of indicator species; and tonrammants
Bjsk Characterization - estimates potential adverse effects from exposure to contaminants
based on exposure and toxicity information. u«imuiras
ecol°9ical effects wnicn c°uld result from exposure to surface soil surface water and
contamina snu- effects to a^
contaminants in surface water and sediment were also evaluated in the ERA.
uotnPOhr adV6rSe ecol°9ical effects is based on the Environmental Effects
Porentiafc?L?n and^h5 • T °! *" eStimated 8XP°SUre concentrations/doses for the chemicals
areater thanT thpro ^ reference values (TRVs) for the ecological receptors. If the EEQ is
becomes arel^r!h f ^^ ^ ^^ ecol°9ical effects to occur. As the magnitude of the EEQ
becomes greater than 1, the potential for adverse ecological effects become more significant.
The results of the BRA for the four AREEs are presented in the following paraaraohs A
lound In the dra- RI A
AREE 9 • Vehicle Maintenance Area
t AREE 9 d06S n0t P°Se an unacceptable human health risk
thheco°9'ca! effects under either current or potential future land-use
a" the chemicals of P°tential concern in surface soil identified for AREE 9 in the
™*H* ^ ^ statisticallV determined to be within background
er-bound excess lifetime cancer risks and noncarcinogenic risks for site-
SShan 1X1°
H H Hl °f °-1' resPec«vely. However, risks associated with
mure of rhm , "^ be assessed in the BRA because this analytical parameter represents a
m,xture of chemical constituents. Since TPH measurements give no indication of the chemical
11
-------
constituents present or their respective concentrations, they cannot be used to predict risks. Although
risks associated with TPH cannot be estimated, TPH contamination in subsurface soil beneath the Military
Motor Pool neutralization pit is recommended for remediation because TPH concentrations exceed the
Virginia TPH soil action level for USTs. The impacted area is approximately 3 ft x 3 ft, extending from the
base of the neutralization pit at 4 ft below ground surface to bedrock at 8.5 ft below ground surface.
AREE 11 - Former Sewage Treatment Plant
The HHRA concluded that, under current land-use conditions, the risks to workers are unacceptable for
exposure to contaminants in surface soil at AREE 11. Under future land-use conditions, assuming that
AREE 11 is not remediated, the risks to potential adult and child residents are also unacceptable for
exposure to contaminants in surface soil. The highest estimated upper-bound excess lifetime cancer risk
is for adult residents exposed to contaminants in surface soil by dermal contact; this risk is 6x10"4 (i.e.,
six in 10,000 residents may develop cancer caused by "contaminants in the AREE 11 surface soil). The
highest non-carcinogenic risk is for child residents exposed to contaminants in surface soil by incidental
ingestion and dermal contact; the HI is estimated to be 20 for each of these routes of exposure. The
organ systems impacted by noncarcinogenic contaminants at AREE 11 are the liver and kidney. The '
unacceptable human health risks result primarily from chlordane (a pesticide) and mercury. Although the
concentrations of PAHs (specifically benzo[a]pyrene and dibenz[a,h}anthracene) at AREE 11 contribute
to the unacceptable risks posed by dermal contact exposure to contaminants in surface soil, they do not
drh/e the unacceptable risks. The highest estimated upper-bound excess lifetime cancer risk for a PAH
is 2x10'5 (two in 100,000 people) for potential future adult residents from dermal contact exposure to
benzo(a)pyrene. It should be noted that major uncertainties exist regarding the assessment of dermal
contact exposures (particularly associated with dermal absorption factors); therefore, estimated risks are
likely to be over-estimated for the dermal contact exposure route.
The ERA determined that contaminants in surface soil at AREE 11 pose significant potential adverse
ecological effects. The significant potential adverse ecological effects result primarily from DDT (a
pesticide), mercury, anc silver. Mercury results in significant potential adverse ecological effects for
terrestrial plants, terrestrial invertebrates, robins, and shrews, with the greatest potential adverse ecological
effects occurring to robins (EEQ of 573). Silver and DDT result in significant potential adverse ecological
effects to terrestrial plants (EEC of 60) and robins (EEQ of 51), respectively.
The most significant contamination is in the sludge pile area, which is recommended for remediation. The
impacted area has dimensions of 45 ft in diameter and 0.5 ft deep, with contamination extending to 1.5
ft below ground surface in an isolated location near the center of the sludge pile area The drying bed
area, which has dimensions of 25 ft x 40 ft x 1.5 ft deep, is less contaminated. One isolated surface soil
tocation in the drying bed area (sample location SS-11 -004 as shown on Figure 4) is recommended for
remediation.
AREE 19 - Pistol Range
The HHRA concluded that, under both current and future land-use conditions, the risks to workers.
trespassers, residents, and excavation workers are acceptable for exposure to site-related contaminants.
except for possibly lead, in soil at AREE 19. Discounting naturally-occurring metals that were statistically
determined to be within background concentrations, the estimated upper-bound excess lifetime cancer
risks from exposure to site-related contaminants in surface soil for all potential receptors and routes of
exposure are less than 1x10"6, while the highest noncarcinogenic risk (HI = 0.8) is for child residents
exposed to site-related contaminants in surface soil by incidental ingestion. Although the HHRA
determined that lead concentrations in surface soil at AREE 19 are below background levels based on
statistical comparisons of site and background concentrations, the lead contamination at AREE 19 is
known to be site-related. The human health risks associated with exposure to lead in surface soil at AREE
19 were evaluated using the Integrated Exposure Uptake Biokinetic (IEUBK) Model recommended by
USEPA for evaluating lead exposures for young children in residential settings. The IEUBK Model
calculates blood lead levels which result from exposures to lead which may then be compared to blood
12
-------
^nreStd t°XiCOl°9ical significance for purposes of risk evaluation. The iEUBK Model run for ARPP
at AREE 19 poses a Si9nlfteant potential
27 - Sand FWer Serfs
REMEDIAL ACTION OBJECTIVES
p h6alth and the environment The remedia,
^ks tn hL ? 'S tO m'n'mize the P°tential for contaminated soils to pose
risks to human or ecological receptors. •
CLEANUP LEVELS ESTABLISHED FOR THE PREFERRED ALTERNATIVE
excess S?mf rpnl ? , ^^ levels for ARE^ " based on eithera IxlO'5 (one in 100,000 people
more st nS ^^Z!T^" ******* qUM °f 1 f°r ^^^ns, whichever was
more stringent for the potential future residential use scenario. However, the soil cleanup levels for DDT
?nT^1cT±^^^?!qb^ °n C0ncentra"-0- vnlch are. protect J J^S^p^
receoTo s bv the u ? P h H !?n'!,fased °" 3 '8Vel recommended for the protection of ecological
receptors by the U.S. Fish and Wildlife Service. The soil cleanup level for AREE 21 is
P'ors' The cleanuolevel for 2 3,7 8-TCDF
concentration at AREE 21 °f
13
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Table 1
Cleanup Levels Established for Soils at the Four AREEs.
Constituents
AREE 9 - VEHICLE MAINTENANCE AREA
Total Petroleum Hydrocarbons
100 (a)
AREE 11 - FORMER SEWAGE TREATMENT PLANT
Aldnn (Human Health risk) (b)
Cadmium (Human Health risk) (b)
Chlordane (Human Health risk)
alpna-Chlordane (Human Health risk) (b)
oamma-Chlordane (Human Health risk) (b)
DDTr (Ecolooical risk only)
Mercury (Human Health & Ecolooical risk)
Saver (Ecological risk only)
0.54 (c)
78 (c)
S'(c)
5(c)
5(c)
0.26 (d)
0.29 (d)
20 (d)
AREE 19 - PISTOL RANGE
Lead (Human Heafih & Ecological risk)
200 (e)
AREE 21 - SAND FILTER BEDS
Z3.7.B-TCDF (Eeotooical risk only)
LIZxIO"* (d)
{a} Virginia total petroleum hydror-arbon soil action level for underground storage tanks.
(b) These compounds contribute to but do not drive unacceptable risk.
(c) Based on either a 1x10-5 upper-bound excess lifetime cancer risk for carcinogens or a hazard
quotient of 1 ior noncarcinogens, whichever is more stringent for the potential future residential
use scenario.
-------
SUMMARY OF REMEDIAL ALTERNATIVES
- ASEEs 9, „. and ,g. As
^^
Alternative 1 - No Action; and
Alternative 2 - Soil Removal.
Alternative 1 - Wo Action
under thi<5aif0rnaV,w» i .7 •<=»"««,. ,MU action would be taken to address site
unuer Tnis alternative. In accordance with Section 121 ofCFRPi A HA auuicaa =>ue
once every five vears to rp px/ai t ;* .. ^tnoLA, each AREE would be reviewed at least
protect human health and the environment.0"^110"8 ^ l° determine the need for remedial action to
Alternative 2 - Soil Removal
JvlrS^rH H6d S0i' exceedin9the established cleanup levels would be excavated
— deor^-iP^^
urn! ImoJf f Cfated as Part of ™s alternative, followed by
uate removal of all soil exceeding the cleanup levels. Upon
.™,«u u, H«vea iMHtt g, The five vear f^^ ^ baclfilled' re9raded, and either vegetatively
substances would not remain on site 3PP y l°thiS atternative beca"se hazardous
EVALUATION OF ALTERNATIVES
°r not a ramed>' wl" mea a» °< *«
Long-term effectiveness anri PPrmgoQn.Q refers to th bj|j f ma
rehatte protection of human health over time, once c.eanup ! goals ™e*L* ?met
Reduction of toxicitv, mobility, or volume thm. .oh trQ^^^^> =„ t< ____ ..-.._ , . .
oTIhe-l.Balu.ent technologies a remedy X employ ' ant'c'P^ed performance
15
-------
Short-term effectiveness addresses the period of time needed to achieve protection and
any adverse impacts on human health and the environment that may be posed durino
the construction and implementation period until cleanup goals are achieved.
Implemeniability is the technical and administrative feasibility of a remedy, includinc the
availability of materials and services needed to implement a particular option.
* Cost includes estimated capital and operation and maintenance costs and net oresen*
worth costs.
Regulator acceptance indicates whether, based on their review of the Rl and Proposed
Plan, the regulators (VDEQ and USEPA) concur, oppose, or have no comment on the
preferred alternative at this present time.
* Community acceptance will be assessed in the Decision Document following a review o'
the public comments received on the Rl and the Proposed Plan.
The comparative anatysis of the alternatives was conducted based upon these evaluation criteria and is
described below.
Overall Protection of Human Health and the Environment
The no action alternative (Alternative 1) is not protective of human health or the environment because the
risks to potential future residents and the potential adverse effects to ecological receptors remain
unchanged, which is unacceptable. Therefore, the no action alternative was eliminated from further
consideration and wfll not be discussed further.
Alternative 2 provides adequate protection of human health and the' environment by removing
contaminated soils, thereby eliminating the potential for exposure.
Compliance with ARARs
Alternative 2 has beer designed to acnieve or comply with ARARs. This alternative will satisfy the
established cleanup levels since all soil that is contaminated above applicable cleanup levels will be
removed. In addition, the remowa' and disposition of contaminated soil during implementation of
Alternative 2 would be done in accordance with federal and Virginia solid and hazardous waste
regulations. During soil excavation, Virginia Regulations for the Control and Abatement of Air Pollution
may apply. Ambient air conditions would be monitored during excavation activities to assure acceptable
air quality. As necessary based on the ambient air monitoring, water sprays would be used to keep dust
levels down.
*
Long-term Effectiveness and Permanence
Alternative 2 would provide for the permanent removal of contaminated soil to a permitted off-site location
• designed to prevent contaminant migration and exposures to human and ecological receptors.
Reduction of Toxicity, Mobility, or Volume Through Treatment
Alternative 2 provides reduction of contamination at the AREEs by removing contaminated soils. The
toxicity and volume of the contaminated soil would not be affected by this alternative; however, the
mobility of the contaminants would be reduced because the off-site disposal facilities used would be
designed to prevent contaminant migration.
16
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Short'term Effectiveness
Implementability
avaTabfe6^
imp'ementable' Licensed
and permitted disposal facilflss
Cost
The cost to implement Alternative 2 is estimated at $360,000.
Regulator Acceptance
thfe PropoSBd Plaa VDEQ and USEPA commems
Community Acceptance
Community acceptance of the preferred alternative will be evaluated at the close of the public comment
penod by centering both oral and written comments received during the public comment peTd
PREFERRED ALTERNATIVE
Memative 2 Soil Removal, is recommended by the U.S. Army as the preferred alternative for AREEs 9
, I N° further actlon 1S required for AREE 21 based on the established soil cleanup level This
m^uViPPTan7? S°'Uti0n that 0fferS 'Ong-term effectivenes- -ince the contamfna ed son
be desned to romn^ >H !adAoanS-K?rted °ff Site f°r pr°per disposal' This remedial alternative would
vM^?1 ^ • ?.?avation 3nd diSp°Sal °f conta^nated soil would be done
with federal and Virginia solid and hazardous waste regulations The estimated
" ' *
17
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Tho United Slates Amy
at Vint Hill Farms Station, Virginia
Invites Public Commont
ON A PROPOSED ENVIRONMENTAL CLEANUP
Concerning Four Areas
Requiring Environmental Evaluation: 0,11,19, & 21
I'lcase Conic To Our
• PUBLIC MEETING.
Tlim-sday, September 18,1997 • 7:110 p.m."
• WniTciitnii Middle Srlinnt Auditorium •
2W Wnlerli» Slirol • Wnrrcnlon, VA
("Sinn IjniRiiane luliT|iri!lcrw|i|| lie prcwnl)
E1JRPQSE: TO DISCUSS AND PRESENT THE REMEDIAL
ALTERNATIVES FOR THE SITES IDENTIFIED ABOVE
The U.S. Army; In consultation will, the U.S. Environmental Prolecllo.
Agency (USEPA) Region III and the Virginia Department o
Environmental Quality (VDEQ). invites public commeni on Us proposec
*m for remediating conlamlnaled soil at the following Areas Reqtiirlm
Environmenlal Evaluallon (AREEs) on Vint Hill Farms Slalion (VHFS)
Virginia: AREE 9 - Vohlcle Maintenance Area; AREE 11 - Former
Sewage Treatment Plant; AREE 19 - Pistol Range; and AREE 21 - Sand
Filler Beds. Before selecting a final remedy. VHFS will consider al
written and oral comments received during the public commeni period. •
The U.S. Army will be accepting comments during a
30-DAY PUBLIC COMMENT PERIOD which
begins Thursday. September 11 S ends Friday. OcloberlO, 1997
VRITTEN COMMENTS IMAV BE SUUMITTFI) TO TIIF
01 LOWING ADDRESS:
Kevin Belt, Public Affairs Officer
Public Affairs Office (Bldg. 101)
Vint Hill Farms Station
Warrenton, VA
2*4!
M
2
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ATTACHMENT 2
4
CLEANUP LEVEL DEVELOPMENT DOCUMENTS
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HUMAN HEALTH RISK-BASED REMEDIATION GOALS
AREAS REQUIRING ENVIRONMENTAL EVALUATION JAREEsl 11 AND 19
VINT HILL FARMS STATION fVHFSl
Risk-based remediation goals for VHFS based on human exposures at the site were calculated for selected
chemicals detected in surface soil in areas proposed for remediation (i.e., surface soil at AREEs 11 [Former
Sewage Treatment Plant] and 19 [Pistol Range]). Based on a review of the exposure pathways evaluated in
the risk assessment, risk-based remediation goals were calculated for chemicals contributing to pathway
upper-bound excess lifetime cancer risks greater than IxK)-4 and/or hazard indices (His) greater than or
equal to 1. The development of risk-based remediation goals focused on the incidental ingestion exposure
pathway only. Although cancer risks exceeding IxlO'4 were associated with dermal contact exposure to
surface soil at AREE 11, risk-based remediation goals did not incorporate exposures through this route due
to the great uncertainties associated with assessing dermal exposures. For example, major uncertainties
exist in the extent to which chemicals are percutaneously absorbed and in the extent to which chemicals
partition from soil to skin leading to uncertainty in the use of default dermal absorption factors in the
evaluation of risk. Uncertainties also exist in the use of adjusted oral toxicity criteria to evaluate dermal
exposure pathways depending on how closely the factors used to adjust oral toxicity criteria reflect the
difference between the oral and dermal routes. .
In the VHFS human health risk assessment (HHRA), surface soil incidental ingestion pathways with upper-
bound excess lifetime cancer risks greater than 1x10^ and/or His greater than or equal to 1 were associated
with adult and child resident exposures at AREE 11. Therefore, risk-based remediation goals for selected
chemicals in surface soil at AREE 11 were developed based on the more conservative residential receptor,
consistent with USEPA Region III methodology for calculating risk-based concentrations (i.e., using
combined child/adult residential exposure parameters for carcinogenic compounds and using child residential
exposure parameters for noncarcinogenic compounds).
Once the relevant exposure, media and receptor were identified, risk-based remediation goals were
calculated for carcinogenic chemicals associated with chemical-specific risks greater than or equal to IxlO"6
and noncarcinogenic chemicals contributing to a HI of 1 for a specific target organ. Risk-based remediation
goals were not calculated for inorganic compounds that were statistically determined to be within background
levels in the risk assessment. For selected carcinogenic chemicals, risk-based remediation goals were
developed using a target risk level'of IxlO-6, which is at the low end of USEPA's target risk range for health-
protectiveness at Superfund sites. For selected noncarcinogenic chemicals, risk-based remediation goals
were calculated to correspond to a target hazard quotient of 1. If any of the noncarcinogenic compounds for
which remediation goals were calculated had similar target organs/critical effects, then the risk-based
remediation goal for that noncarcinogenic compound was divided by the number of compounds having the
same target organ/critical effect (i.e., if two noncarcinogenic compounds had "liver" as the target organ, the
individual remediation goals would be divided by two). For chemicals that exhibit both carcinogenic and
noncarcinogenic effects (e.g., chlordane), the selected remediation goals represent the lower of the
calculated carcinogenic and noncarcinogenic remediation goals.
The following sections present the exposure assumptions and equations used to calculate the risk-based
remediation goals for chemicals in surface soil. Table 1 presents the toxicity criteria used to calculate the
risk-based remediation goals for chemicals in surface soil.
Surface Soil Risk-Based Remediation Goals
Risk-based remediation goals were calculated for chemicals in surface soil based on combined child/adult
resident exposures for carcinogens and on child resident exposures for noncarcinogens for the incidental soil
ingestion pathway. The equations and exposure assumptions used to calculate risk-based remediation goals
for surface soil are presented below. Equations are presented separately for chemicals exhibiting
carcinogenic and noncarcinogenic effects.
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TABLE 1
CHRONIC ORAL TOXICITY CRITERIA
Oral Toxlclty Criteria, for Carclnogans
Chemical
Organlcs
Aldrin
Chlordane
alpha-Chlordane
gamma-Chlordane
Inorganics
Cadmium
Lead
Mercury
Oral Slope
Factor
(mg/kg-day)'1
1.7E*01
1.3E+00
1.3E+00
1.3E+00
—
—
•MP*.
Weight-of-
Evidence
Class (a;
B2
B2
B2
B2
B1
B2
D
Slope Factor
Source
IRIS
IRIS
IRIS
IRIS
IRIS
IRIS
IRIS
Oral Toxicity Criteria for Noncarclnooens
Chronic Oral
Reference Dose
(RfD)
(mg/kg-day)
3E-05
6E-05
6E-05
6E-05
1E-03 (d)
—
3E-04
Uncertainty
Factor (b)
1.000
1.000
1,000
1,000
10
—
1.000
Target Organ/
Critical Effect (c)
Liver
Liver
Liver
Liver
Kidney
CNS
Kidney
— -
4ttk
JJUPaurc
fRIS
IR.'S
IRIS
IRIS
IR!S
RIS
H5AST
(a) USEPA weight-of-evidence classification scheme for carcinogens:
A c Human Carcinogen, suffident evidence of carcinogenicity in humans:
B1« Probable Human Carcinogen, limited human data are available:
82 * Probable Human Carcinogen, sufficient evidence of carcinogenicity in animals with inadequate or lack of evidence in humans;
C * Possible Human Carcinogen, limited evidence from animal studies in the absence of human 'studies; and
D « Not classified as to human carcinogenicity, inadequate or no evidence. '
(b) Uncertainty factors presented are the products of specific uncertainty factors and modifying factors. Uncertainty factors used to
develop reference doses generally consist of multiples of 10, with each factor representing a specific area of uncertainty in the
data available. The standard uncertainty factors include:
- a 10-fold factor to account for the variation in sensitivity among the members of the human population;
- a 10-fold factor to account for the uncertainty in extrapolating animal data to the case of humans;
- a 10-fold factor to account for the uncertainty in extrapolating from less-than-chronic NOAELs to chronic NOAELs; and
- a 10-fold factor to account for the uncertainty in extrapolating from LOAELs to NOAELs.
Modifying factors are applied at the discretion of the RfD reviewer to cover other uncertainties in the data and range from 1 to 10.
(c) A target organ or critical effect is the organ/effect most sensitive to the chemical exposure. RfDs are based on toxic effects in the
target organ or critical effects. If an RfD is based on a study in which a target organ or critical effect was not identified, the
organ/effect listed is one known to be affected by the chemical.
(d) For exposures to cadmium in food.
NOTE:
IRIS * Integrated Risk Information System - USEPA.1996.
HEAST » Health Effects Assessment Summary Tables - USEPA. 1995.
— * No information available.
CNS * Centre! Nervous System.
-------
The equation used to calculate risk-based remediation goals for chemicals exhibiting carcinogenic effects
using the combined child/adult exposure parameters based on USEPA (1991), is as foHows
c = TR * ATc * 365 days/year
. EF * JFA * SFa * Iff6 kg/mg
where:
c* = chemical concentration in surface soil (mg/kg),
TR = target excess individual lifetime cancer risk (1 xlO"6),
AT= = averaging time for carcinogenic effects (70 years), '
EF = exposure frequency (350 days/year),
IFA = adjusted integrated factor (see below) (114.3 mg-year/kg-day), and
bHo - oral cancer slope factor [(mg/kg-day)-1] (see Table 1).
The combined child/adult resident exposure parameters used .to calculate carcinogenic risk-based
remed,at,on goals for ,nc,dental ingestion of surface soil incorporate an age-adjusted fector which
approx.mates the integrated exposure from birth until age 30 by combining contact rates bodv^etahtTa2
SESEi*11??" f°r "^ Chi'dren and y°Un9 adUltS (USEPA' 1997>' The age-adjusted ScSr'was
calculated as follows, using exposure parameters from USEPA (1991)-
IFA= EDc * IRc i ^EDtot-EDc) * IRa
BWc BWa
where:
IFA = age-adjusted integrated factor (mg-year/kg-day),
EDc = child's exposure duration (6 years),
IRo = child's soil ingestion rate (200 mg/day),
BWC = child's body weight (15 kg),
EDtot = total exposure duration (30 years),
IRa = adult's soil ingestion rate (100 mg/day), and
BWa = aduJt's body weight (70 kg).
ffLte,qu5n°nnthUSeH-lH° CaiCUiate risk-based ^mediation goals for chemicals exhibiting noncarcinogenic
effects, using the child exposure parameters obtained from USEPA (1991), is as follows:
C = THI * BW * AT«< * 365 days /year
EF * ED-*(l/RfDj * IQ* kg/mg * IRsoil
where: .
cs . = chemical concentration in soil (mg/kg),
TH! = target hazard index (1),
BW = body' weight (15 kg),
ATnc = averaging time for noncarcinogenic effects (6 years),
EF = exposure frequency (350 days/year),
ED = exposure duration (6 years).
RfD0 = oral chronic reference dose (mg/kg-day) (see Table 1 ), and
IRsoii = soil ingestion rate (200 mg/day).
-------
Summary of Risk-Based Remediation Goals
Risk-based remediation goals for AREEs 11 and 19 were calculated for selected chemicals in surface soil.
Specifically, risk-based remediation goals were calculated for all chemicals associated with chemical-specific
risks greater than or equal to 1x1 Q/6 or chemicals contributing to a HI greater than or equal to 1 for a specific
target organ for the incidental ingestion exposure pathway. Risk-based remediation goals were not
calculated for inorganic compounds that were statistically determined to be within background levels. Risk-
based remediation goals for all selected chemicals in surface soil were developed based on conservative
child/adult resident receptors for carcinogens and on child resident receptors for noncarcinogens. Risk-
based remediation goals for surface soil are presented in Table 2.
Based on a review of the chemicals and pathways evaluated in the risk assessment, risk-based remediation
goals for surface soil were calculated for aldrin, chlordane, alpha-chlordane, gamma-chlordane, cadmium,
and mercury detected at AREE 11; and lead detected at AREE 19. At AREE 19, the maximum lead
concentration (5,850 mg/kg) was approximately 14 times greater than USEPA's 400 mg/kg residential soil
screening level for lead, and the arithmetic mean concentration (949 mg/kg) was approximately twice the
screening level. USEPA's residential soil screening level for lead was developed using the Integrated
Exposure Uptake Biokinetic (iEUBK) model (USEaA. 1994) and is based on residential exposures by the
most sensitive members of the population (i.e., young children). Since a risk-based remediation goal cannot
be calculated for lead due to a lack of available quantitative carcinogenic and noncarcinogenic toxicity
criteria, the 400 mg/kg residential soil screening level for lead is presented in Table 2 as the remediation goal
for lead in surface soil.
References
U.S. Army Environmental Center (USAEC). 1997. Remedial Investigation. Vint Hill Farms Station Phase I
* Reuse Area Remedial Investigation/Feasibility Study. Draft Document Prepared by IGF Kaiser
Engineers, Inc., Edgewood, Maryland. April, 1997.
U.S. Environmental Protection Agency (USEPA). 1991. Risk Assessment Guidance for Superfund.
Volume 1: Human Health Evaluation Manual Supplemental Guidance. Standard Default Exposure
Factors. Interim Final. Washington, D.C. OSWER Directive 9285.6-03. March 25.1991.
U.S. Environmental Protection Agency (USEPA). 1994. Revised Interim Soil Lead Guidance for CERCLA
Sites anc RCRA Corrective Action Facilities. Memorandum to Regional Administrators from Elliot P.
Laws, Assistant Administrator. Solid Waste and Emergency Response, OSWER Directive #9355 4-
12. EPA/540/F-94/043.
U.S. Environmental Protection Agency (USEPA). 1995. Human Health Effects Assessment Summary
TaWes (HEAST). Office of Health and Environmental Assessment, Environmental Criteria and
Assessment Office, Cincinnati, Ohio. Prepared for Office of Solid Waste and Emergency Response,
Office of Emergency and Remedial Response. Washington, D.C. FY-1995.
U.S. Environmental Protection Agency (USEPA). 1996. Integrated Resource Information Systems (IRIS).
Environmental Criteria and Assessment Office. Cincinnati, Ohio.
U.S. Environmental Protection Agency (USEPA). 1997. Risk-Based Concentration Table. March 17,1997.
-------
TABLE 2
REMEDIATION GOALS FOR CHEMICALS IN SURFACE SOIL (a)
Carcinogenic
(mg/kg-day).1
Nonearcinogenic
(mg/kg-day)
Carcinogenic (fa)
AREE 11
Resident Ingestion
Aldrin
Chlordane
alpha-Chlordane
gamma-Chlordane
Cadmium
Mercury
AREE19
Child Resident Ingestion
Lead
1.7E+01
1.3E+00
1.3E+00
1.3E+00
3E-05
6E-05
SE-05
6E-05
1E-03
3E-04
0.038
0.49
0.49
0.49
0.59
1.2
1.2
1.2
39
12
Selected
Remediation
Goal
Jmgikg) (d)
0.038
0.4S
0.49
0.49
39
12
400 (e)
(a) Remediation goals were calculated for predominaht chemicals (i.e.. chemicals with risks exceed™ 1x10* or
chem,cals contributing to a HI greater than or equal to 1 for a specific target organ) for the incidental ingestion
pathways associated with a total excess lifetime cancer risk exceeding 1x10^ or a HI greater than or equal to 1
^l?fad remediaUor'90als for <=a™sanic chemicals were based on a target risk level of 1x10« and were
calculated using combined child/adult exposure parameters
(c) The calculated remediation goals for noncarcinogenic chemicals were calculated using child resident exposure
parameters, and were based on a hazard quotient of 1. The remediation goals for aldrin, chlordane alpha-
chlordane. and gamma-chlordane were divided by four since they all have the liver as the target organ' the
MX TK ,'a"°" goals for "d™""! and mercury were divided by two since both have the kidney as the taraet organ
(d) The selected remediation goal represents the lower of the calculated carcinogenic and noncLnogenic
remediation goals. • '
(e) The selected remediation goal is USEPA's residential soil screening level for lead (USEPA 1994).
-------
-------
ECOLOGICALLY-BASED CLEANUP LEVELS
AREAS REQUIRING ENVIRONMENTAL EVALUATION fAREEs) 11.19. AND 21
VINT HILL FARMS STATION WHFS)
Results of the Ecological Risk Assessment (ERA) conducted as part of the Phase I Reuse Area
Remedial Investigation (Rl) at VHFS (USAEC, 1997) indicate the potential for adverse effects to ecological
resources at several on-site locations. Surface soils at AREEs 11, 19, and 21 were identified as having
the greatest potential to adversely affect ecological resources and were selected for remediation. The
following ecological receptors were identified as having the greatest potential to be adversely affected in
each of these areas:
AREE 11 (Former Sewage Treatment Plant)
Terrestrial plants from the presence of silver in surface soil; and
Robins from the presence of mercury and DDTr in surface soil.
AREE 19 (Pistol Range)
Terrestrial plants from the presence of lead in surface soil.
AREE 21 (Sand Filter Beds)
Robins from the presence of 2,3,7,8-TCDF in surface soil.
The objective of this document is to identify the reduction in chemical concentrations necessary to be
protective of these ecological resources. Because of the conservative nature of the toxicological values
and exposure estimates, cleanup levels were derived based on an EEQ1 of 10. The following sections
derive cleanup levels for each of these areas based on the ecological resources at risk.
AREE 11 (Former Sewage Treatment Plant)
Terrestrial Plants . ,
Results of the ERA indicate the potential for adverse effects to terrestrial plants from the presence
of silver in surface soil at AREE 11. A literature-based toxicity value of 2 mg/kg derived by Will and Suter
(1994) and used in the ERA to evaluate the potential for adverse effects to terrestrial plants vyas used to
derive the cleanup level for silver in surface soil. Using this toxicity value and a target EEQ of 10, the
cleanup level for silver in surface soil at AREE 11 is 20 mg/kg.
Terrestrial Wildlife
Results of the ERA indicate the potential for adverse effects to robins from the presence of
mercury and DDTr in surface soil at AREE 11. Attachment A outlines the screening model and input
parameters used in the ERA to estimate the potential for adverse effects to robins. Assumptions in this
model were designed to provide a highly conservative estimate of the potential for adverse effects to
robins. One of the most conservative assumptions in the model is that robins would be exposed to the
estimated average mercury and DDTr concentrations detected in the VHFS Phase I reuse area (1.14
mg/kg and 0.0918 mg/kg, respectively). However, as discussed in the Rl, samples were biased to areas
of likely contamination, and samples from these areas are likely to over-estimate actual levels of
1The Environmental Effects Quotient (EEQ) is the ratio of the estimated exposure concentration/dose
for the chemical of concern and the toxicity reference value (TRV) for the ecological receptor of concern.
-------
contamination throughout the facility. Further, the highest mercury and DDTr concentrations were
detected within very localized areas of AREE 11. The areas of mercury and DDTr contamination in surface
soil at AREE ", 1 are the sludge pile, which is 45 feet in diameter, and the drying bed, which is 25 feet by
40 feet in size. Mercury and DDTr detected in these areas are the primary drivers of the estimated risks
to robins at VHFS. Accordingly, robins are likely to be exposed to mercury or DDTr in only a limited
proportion of their total foraging area and, because of the biased sampling methodology, using an
average of the Phase I reuse area concentrations detected in surface soil will likely over-estimate the
potential for exposure and adverse effects.
Cleanup levels were determined by backcalculating through the risk model used in the ERA. Two
approaches were used to develop cleanup levels for robins. The first approach assumes the total area
to which robins would be exposed is equal to the entire VHFS Phase I reuse area. This approach is
consistent with that used in the ERA and simply requires determining, by backcalculating through the
equations presented in Attachment A, an average exposure concentration which is equal to 10 times the
toxicity value used in the ERA (i.e., an EEQ of 10). However, this approach is likely to over-estimate risks
because it assumes the average Phase I reuse area exposure concentration, estimated by averaging the
concentrations of chemical detected at surface soil sample locations, is an accurate indicator of chemical
concentrations throughout the Phase I reuse area. The second approach applies a spatial factor to adjust
for the area of actual contamination. This latter approach is expected to provide a more realistic estimate
of exposure.
The spatial factor used for the second approach was derived by first estimating the total area over
which a robin is likely to forage. Pitts (1984) estimated an average territory size of 0.42 hectares (equal
to 45,208 square feet) for robins on a college campus in Tennessee. Based on this territory size and the
assumption that robins would forage in a roughly circular area around their nests, a robin foraging in
AREE 11 could also be exposed to mercury and DDTr in surface soil at AREE 24 (Transformer Storage
Area). Although the mercury and DDTr concentrations detected at AREE 24 are lower than those
detected at AREE 11, the chemicals detected in AREE 24 could affect the overall potential for adverse
effects to robins. Accordingly, cleanup levels for AREE 11 were calculated assuming robins could be
exposed to mercury and DDTr at both AREEs 11 and 24. Mercury and DDTr were not detected at any
other AREEs within the foraging range of robins at AREE 11.
The total area of potential mercury and DDTr contamination to which a robin foraging at AREE
,11 could be exposed was estimated to be 2,990 square feet by summing the potentially contaminated
areas in AREE 11 (2,590 square feet) and the potentially contaminated area in AREE 24 (400 square feet).
The proportion of the total foraging area at which a robin associated with AREE 11 could be exposed to
me-cury or DDTr was then estimated by dividing the estimated total area contaminated with mercury and
DDTr by the robin's estimated territory size. Using this approach, a proportion of 0.066 was estimated.
This proportion was then used as a multiplier in equations (2) and (5) of Attachment A.
Cleanup levels derived using the approaches described above are presented in Table 1. The
approach which accounts for the limited distribution of mercury and DDTr in the territorial range of robins
results in higher cleanup levels. However, these cleanup levels are expected to be more realistic and are
recommended for use as the final cleanup levels. Consistent with the ERA, cleanup levels were also
derived for both inorganic and organic mercury (methylmercury). Although it is likely only a proportion
of the mercury detected in surface soil is present in the organic form, it is recommended that the more
conservative methylmercury cleanup level be selected as the cleanup level for AREE 11.
-------
Table 1
Surface Soil Cleanup Levels for the Protection of Terrestrial Wildlife
DDTr
Mercury (inorganic)
Methylmercury
2,3,7-,8-TCDF
0.018
0.36
0.02
2.9E-06
0.26
5.19
0.29
1.12E-04
(a)
(a)
(a)
(b)
(a) Cleanup level for AREE 11.
(b) Cleanup level for AREE 21.
-------
AREE 19 {Pistol Range)
Terrestrial Plants
Results of the ERA indicate the potential for adverse effects to terrestrial plants from the presence
of lead in surface soil. A literature-based toxicity value of 50 mg/kg derived by Will and Suter (1994) was
used in the ERA to evaluate the potential for adverse effects to terrestrial plants. Using this toxicity value
and a target EEQ of 10, the cleanup level for lead in surface soil at AREE 19 is 500 mg/kg.
AREE 21 (Sand Filter Beds)
Terrestrial Wildlife
Results of the ERA indicate the potential for adverse effects to robins from the presence of 2,3,7,8-
TCDF in surface soil at AREE 21. Attachment A outlines the screening model and input parameters used
in the ERA to estimate the potential for adverse effects to robins. Assumptions in this model were
designed to provide a highly conservative estimate of the potential for adverse effects to robins. The most
conservative assumption in the model is that robins would be exposed to the average of the 2,3,7,8-TCDF
concentrations detected in the VHFS Phase I reuse area (1.11E-05 mg/kg). However, as discussed in the
Rl, the highest 2,3,7,8-TCDF concentration was detected in a very localized area of AREE 21. The area
of 2,3,7,8-TCDF contamination in surface soil that is driving the risk to terrestrial wildlife is the absorption
bed area of AREE 21 which is approximately 375 feet by 3 feet in size. Accordingly, robins are likely to
be exposed to this chemical in only a very limited proportion of their total foraging area, and the use of
an average Phase I reuse area exposure concentration will likely overestimate the potential for exposure
and adverse effects to robins.
Cleanup levels for 2,3,7.8-TCDF were calculated for AREE 21 using the same methods described
earlier to derive cleanup levels for mercury and DDTr at AREE 11. The contaminated proportion of the
total territory size was estimated to be 0.025 assuming the contaminated area of AREE 21 is 1,125 square
feet in size. Only AREE 21 was factored into the calculation because no other areas of 2,3,7,8-TCDF
contamination occur within the range of a robin foraging in AREE 21. The cleanup levels derived for
2,3,7,8-TCDF are summarized in Table 1. It is recommended that the cleanup level derived using the
approach which accounts for the spatial distribution of 2,3,7,8-TCDF be used as the cleanup level for
AREE 21.
Summary of Cleanup Levels
Table 2 presents the cleanup levels for chemicals of significant ecological concern in surface soil
for AREEs 11,19, and 21. It should be noted that the cleanup level derived for 2,3,7,8-TCDF (1.12E-04
mg/kg) is higher than the maximum detected concentration at AREE 21 of 8.71 E-06 mg/kg, indicating that
remediation of AREE 21 may not be required when its areal extent is considered.
References
Pitts, T.D. 1984. Description of American Robin Territories in Northwest Tennessee. Migrant 55:1-6.
Will, M.E. and Suter, G.W., II. 1994. Toxicological Benchmarks for Screening Potential Contaminants of
Concern for Effects on Terrestrial Plants. Rev. ed. Oak Ridge National Laboratory, Oak Ridge,
TN. ES/ER/TM-85/R1.
U.S. Army Environmental Center (USAEC). 1997. Remedial Investigation. Vint Hill Farms Station
Phase I Reuse Area Remedial Investigation/Feasibility Study. Draft Document. Prepared by
1CF Kaiser Engineers, Inc., Edgewood, Maryland. April, 1997.
4
-------
Table 2
Cleanup Levels for Chemicals in Surface Soil
AREE 11
DDTr
Mercury
Silver
0.26
0.29
20
AREE 19
Lead
500
AREE 21
2,3,7,8-TCDF
1.12E-04
-------
ATTACHMENT A
ESTIMATION OF ROBIN EXPOSURE TO CHEMICALS
FOR THE DERIVATION OF CLEANUP LEVELS
The following sections present the methods used to calculate the potential ingestion of chemicals
by robins from the ingestion of food (i.e., earthworms) and surface soil. The equations given below were
derived based on equations presented by USEPA (1989). Table A-1 presents specific exposure parameter
values used in these equations. K<* «*•«"«
Total Dose
The total dietary exposure levels for robins to. chemicals was determined using the followina
equation: a
' <1>
where:
. Doseworm = amount of chemical ingested per day via ingestion of earthworms (in mg/kg bw-d
• use equations 2, 3. and 4 to calculate); and
Dosesoi, = amount of chemical ingested per day from soil (in mg/kg bw-d, use equation 5
to calculate).
Dose From Earthworms
The following equation was used to calculate the dose of chemicals that a robin would be
expected to obtain from the ingestion of earthworms:
Ft * Cdiat (2)
where:
Fl = food ingestion rate (kg/kg bw-d); and
^diet - estimated chemical concentration in diet (in mg/kg, use equation 3 to calculate).
The estimated dietary concentration (Cdiet) was calculated using the following equation:
where:
p» = proportion of diet consisting of earthworms (unitless); and
ce = estimated concentration of chemical in earthworms (in mg/kg, use equation 4 to
calculate).
A-1
-------
Table A-1
Summary of Exposure Parameters Used in the Robin Food Ingestion Model
Food ingestion rate (Fl; kg/kg bw-d)
1.52
Proportion of diet consisting of earthworms (Pe; unitless)
0.18
b,c
Bioconcentration factor for chemical
in earthworms (BCF; unitless)
DDTr=1.4 d,e
inorganic mercury = 0.96 f
methylmercury = 27 g
2,3,7,8-TCDF = 14.5 h
Soil ingestion rate (SI; kg/kg bw-d)
0.158
(a) Hazelton et al. (1984) as cited in USEPA (1993).
(b) Wheelwright (1986) as cited in USEPA (1993).
(c) Howell (1942) as cited in USEPA (1993).
(d) Beyer (1990).
(e) Tyler (1973).
(f) Beyer and Stafford (1993).
(g) Eisler(1987).
(h) Eisler(1986).
(i) Beyer etal. (1994).
A-2
-------
The concentration of chemical in an earthworm (CJ as fresh weight was determined using the
following equation: ,
where:
Csoi, = average concentration of chemical detected in surface soil (mg/kg); and
BCF = bioconcentration factor for chemical in earthworms (unitless).
Dose From Soil
The following equation was used to calculate the dose of chemicals that a robin would be
expected to obtain from the ingestion of surface soil:
Dose^ - SI . CKe (5)
where:
SI = soil ingestion rate (kg/kg bw-d); and
C^j, «* average chemical concentration in surface soil (mg/kg).
References
Beyer, W.N. 1990. Evaluating Soil Contamination. USFWS Biological Report. 90(2). July, 1990.
Beyer, W.N. and Stafford, C. 1993. Survey and Evaluation of Contaminants in Earthworms and in Soils
Derived from Dredged Material at Confined Disposal Facilities in the Great Lakes Region. Environ.
Mon'rt. Assess. 24:151-165.
Beyer, W.N., Conner, E., and Gerould, S. 1994. Estimates of Soil Ingestion by Wildlife. J. Wildl.
Manage. 58:375-362.
Eisler, R. 1986. Dioxin Hazards to Fish, Wildlife, and Invertebrates: A Synoptic Review.
Contaminant Hazard Review Report No. 8. U.S. Fish and Wildlife Sen/ice. U.S. Department
of the Interior. May, 1986.
Eisler, R. 1987. Mercury Hazards to Fish, Wildlife, and Invertebrates: A Synoptic Review. Contaminant
Hazard Reviews, Biological Report 85. April, 1987.
Hazelton, P.K., Robel. R.J., and Dayton, A.D. 1984. Preferences and Influences of Paired Food Items on
Energy Intake of American Robins (Turdus migratorius) and Gray Catbirds (Duma'tella
carolinensis). J. Wildl. Manage. 48:198-202.
Howell, J.C. 1942. Notes on the Nesting Habits of the American Robin (Turdus migratorius). Am. Mild.
Nat. 28:529-603.
Tyler, A.V. 1973. Caloric Values of Some North Atlantic Invertebrates. Mar. Biol. 19:258-261.
A-3
-------
U.S. Environmental Protection Agency (USEPA). 1989. Risk Assessment Guidance for Superfund.
Volume!: Human Health Evaluation Manual. Interim Final. EPA/540/1-89/002. December, 1989^
U.S. Environmental Protection Agency (USEPA). 1993. Wildlife Exposure Factors Handbook. Volume
I of II. Office of Research and Development, Washington, D.C. .EPA/630/R-93/187a. '
Wheelwright, N.T. 1986. The Diet of American Robins: An Analysis of U.S. Biological Survey Records
Auk 103:710-725.
A-4
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ATTACHMENT 3
PUBLIC NOTICE
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Please Come To Our
• Warrenlon.
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Fauquier County Library
Warrenton Branch - Reference Seclion
11 Winchester Street
Warrenlon. VA 22186
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M-W 10 am. -9p.m.
Th.Sal:9a.m. .5 p.m. and
Sun 1 p m. - 5 D.m
Phone: (540) 347.8750
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