PB99-963913
EPA541-R99-017
1999
EPA Superfund
Record of Decision:
USA Vint Hill Farms Station
AREEs 13,14,16-1, 27 & 29-4
Warrenton, VA
7/1/1999
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FINAL
DECISION DOCUMENT
AREEs 13, 14, 16-1, 27, AND 29-4
VINT HILL FARMS STATION
WARRENTON, VIRGINIA
Prepared for:
U.S. Army Communications-Electronics Command
Prepared by:
IT Corporation
Edgewood, Maryland
June 1999
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TABLE OF CONTENTS
1.0 INTRODUCTION ..." ;
2.0 SITE BACKGROUND
.,
3.0 SITE CHARACTERISTICS ............... '. ....... .............................
3.1 Site Topography .................................. . .'.'.'.". ........... "" ...................... . ..................... ^
3 2 Adjacent Land Use ...................... '. ............ '."""^'^!Z^'^"' .......... .................... ............. 3
3.3 Surface Water Hydrology .............................................. ,.!..^" ........... ." ........... ' .................
3.4 Geology/Hydrogeblogy [[[ .., . ............................................. . '" 7
.......... " ............... • ................... •- ....... . - . o
4.0 SITE HISTORY AND INVESTIGATION FINDINGS ....... . .5
4.1 AREE 13 -Sludge Disposal Area ................ ...................... ..................... ' ..... =
4.2 AREE 14- Skeet Range ........................................... [[[ " I
4.3 AREE 16-1 - Possible Firefighter Training Pit. [[[ ""
4.4 AREE 27 - AAFES Service Station ....... . ...... .... ............. ". ................................... t
4.5 AREE 29-4 - DisposafArea ......................................... ' ...................... ' ............ . ......... "
50 SUMMARY OF SITE RISKS :
5.1 AREE 13 - sludge Disposal Area !!!!Z!"!!Z!!Z!!!ZZ"!""" ' " '
5.2 AREE 14 - Skeet Range g
5.3 AREE 16-1 - Possible Firefighter Training Pit ' q
5.4 AREE 27 - AAFES Service Station " *
5.5 AREE 29-4 - Disposal Area !ZZZZ"". .'""." 10
6.0 SELECTED ALTERNATIVE 10
7.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION.
10
8.0 RESPONSIVENESS SUMMARY r
8,1 Selected Newspaper Notices '"1..^"''^"."''"' r
8.2 Comments Raised During the Public Meeting on April 15, 1999 -12
8.3 Public Meeting Attendance Roster ' ^''''^Z''7 12
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LIST OF FIGgRES
Figure
1 General Location of VHFS
2 General Locations of AREEs at VHFS
LIST OF ATTACHMENTS
Attachment 1 Response to USEPA Comments on the Final Phase I Reuse Area Rl Repcr
Attachment 2 Response to USEPA Comments on the AREE 14 Investigation Summary Repcr
Attachment 3 Proposed Plan
Attachment 4 Public Notice
Attachment 5 Public Meeting Roster
Attachment 6 Written Comments From Regulators and U.S. Army Responses
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ABBREVIATIONS AND ACRONYMS
AAFES Army, Air Force Exchange Service
A'REE 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
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
NCP 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
SRI Supplemental Remedial Investigation
STP Sewage Treatment Plant
TPH total petroleum hydrocarbon
TRV toxicity reference value
USAGE U.S. Army Corps of Engineers
USAEC U.S. Army Environmental Center
USEPA U.S. Environmental Protection Agency
UST underground storage tank
VDEQ Virginia Department of Environmental Quality
VHFS Vint Hil! Farms Station
in
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DECLARATION FOR THE DECISION DOCUMENT
REMEDIAL ALTERNATIVE SELECTION
Site Name and Location
Areas Requiring Environmental Evaluation (AREEs) 13. 14, 16-1 27 and 29-4
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 che environment for soil at AREEs 13, 14. 16-1, 27, and 29-4 at Vint Hill Farms Station (VHFS)
Warrenton, Virginia. This determination was developed in accordance with the Comprehensive Environmental
*r«P*1Se\lmP?nSa!!°n' !.ncLLiability Act of 198° (CERCLA), as amended by the Superfund Amendments
and Reauthonzation Act (SARA) of 1986 and the National Oil and Hazardous Substances Pollution
Contingency Plan (NCR), 40 C.F.R. Part 300. This document was prepared as a joint effort between the US
AnTL! n IcpD^'a-?KePartrnent °f Environmental Quality (VDEQ). and the U.S. Environmental Protection
Agency (USEPA). The no action decision is supported by documents contained in the Information Repository.
Description of the Selected Remedy
No action is the selected remedy for AREEs 13,14, 16-1, 27, and 29-4. The Baseline Risk Assessment (BRA)
conducted as part of the investigation activities, supports the no action decision.
Declaration
_Jhe no action remedy selection is based upon the findings of the BRA which deter -ined risks within USEPAs
acceptable risk ransej r each of AREEs 13, 14, 16-1, 27, and 29-4. Therefore, the selected remedy is
"""*tne environment. A five-year review will not be necessary for these AREEs.
ROBERT L NABORS
Major General, USA
Commanding
U.S. Army Communications-Electronics Command
1/99
Date
IV
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DECISION SUMMARY
1.0 INTRODUCTION
H.CA^ <6J£a decision is based °n the Phase I Reuse Area Remedial Investigation (Rl) Report
(USAEC, 1998) and the Phase II Reuse Area Rl Report (USAGE, 1999) which include Baseline R:SK
Assessments (BRAs) documenting the risks from contamination in the soil at Areas Requiring Environmental
^«at,'°o-SARE:ES) 13' 14' 16~1' 27' and 2{M' ln the BRA' i{ was determined that the soils at AREEs 13
14 ib-1. 27. and 29-4 do not pose unacceptable risks to human health and the environment Therefore the
soils at AREEs 13. 14, 16-1. 27, and 29-4 require no action to be protective of human health and the'
environment.
2.0 SITE BACKGROUND
^crv^int,Hil1 FarmS Stati°n (VHFS) is part Of the U'S- Army Communications - Electronics Commarc
CECOM) and, while active, pnmarily 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 -sed
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 fBRAC)
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, 1 994, 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 were investigated as part of the Phase I and Phase II reuse area RIs
and the Supplemental Remedial Investigation (SRI) conducted by ICF Kaiser Engineers, Inc. (ICF KE) The
purposes of these reports 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 Reports for the Phase I and Phase II reuse areas
(USAEC, 1998; USAGE, 1999) were completed in April, 1998. and January, 1999, respectively The draft SRI
Report (USAGE, 1998b) was completed in November, 1998.
• Five AREEs were identified in the RIs and SRI as having soil contamination which poses no
unacceptable human health risks and/or significant adverse ecological effects:
• AREE 13 -Sludge Disposal Area;
• AREE 14- Skeet Range;
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ANNE
ARUNDEL
MONTGOMERY
MARYLAND
PRINCE GEORGES
\
VINT HILL
FARMS STATION
*\
PRINCE WILLIAM
KING GEORGE
RGURE1
GENERAL LOCATION
OFVHFS
0 ^^10
SCALE IN MILES
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• AREE 16-1 - Possible Firefighter Training Pit;
• AREE 27 - Army, Air Force Exchange Service (AAFES) Service Station; and
AREE29-4 - Disposal Area.
The :ccations of these AREEs are shown on Figure 2.
3.0 SITE CHARACTERISTICS
3.1 Site Topography
VHFS is located within the Piedmont Plateau physiographic province, approximately 20 miles w°st
of trie Fall Line. The Fall Line is a physiographic boundary that separates the folded and faulted crysta'line
rocks of the Piedmont Plateau physiographic province from the unconsolidated sediments of the Atlantic
Coastal Plain physiographic province. The topography of the Piedmont Plateau in the vicinity of VHFS consists
of gently rolling hills with slopes generally less than 10%. Surface elevations on the installation vary from 335
to 430 feet (ft) above mean sea level (MSL).
3.2 Adjacent Land Use
Land use in the immediate vicinity of VHFS consists mainly of agriculture (mostly horse farms; and
residential areas. With the exception of a few residences to the north, the majority of residential development
is located to the south of VHFS. A small county recreation park is located adjacent to VHFS along South Run.
3.3 Surface Water Hydrology
VHFS is located in the Occoquan watershed. Most of VHFS drains to South Run via intermittent
tributaries and dramage'ditches, as shown on Figure 2. South Run is a small Class III Virginia stream whicr-
discharges into Lake Manassas, a recreation and drinking water reservoir built on Broad Run for the City of
Manassas. Lake Manassas discharges to Broad Run, which drains to the Occoquan Reservoir Drainage for
the southern portion of the installation flows south and east to Kettle Run. Kettle Run converges with Broad
Run approximately 10 miles downstream from Lake Manassas.
3.4 Geology/Hydrogeology
The central portion of VHFS is underlain by folded sedimentary rocks of the Catharpin Creek Member'
which consists of sandstone, arkosic sandstone, siltstone, shale, and claystone. Intrusions of basalt oriented
northeast to southwest, cut the bedrock in the central and western portions of the VHFS installation The
northeastern flank of VHFS is underlain by intrusions of diabase. Quaternary alluvium is present along the
major drainage channels within the installation.
The overburden is thickest (20-40 ft) in the southern regions of the site and thins to 0-10 ft in the
northern areas. The overburden consists primarily of saprolite (a chemical and physical weathering product
of the underlying bedrock) which underlies lesser amounts of clayey and silty soils.
Groundwater at VHFS occurs in fractured bedrock and to a lesser extent in the overburden The
bedrock aquifer is semi-confined, with the unfractured bedrock and saprolite acting as confining units
Recharge to the fractured bedrock aquifer occurs at outcrop areas and from percolation from the overburden
along fractures. In the overburden, the aquifer is unconfined.
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AREEs LOCATIONS:
StUOCC DISTOM WCA
14 SKIP RAIIGC
i6-i. rossimc rmcncmtR IRAIIIIHG PIT
\ 4 7; MfK StRVICC 5IAIWN
29-4 DWOSAl AflrA
PHASE I RfUSE AREA
N
0 400 DM 1600
SCAlTlN
FIGURE 2
GENERAL LOCATIONS
OFAREEsATVHFS
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4.0 SITE HISTORY AND INVESTIGATION FINDINGS
The Ris for these five AREEs were conducted to evaluate the nature and extent of contamination
associated with past site activities. Environmental samples collected and analyzed during he m wee u ed
m conjunction with the results from the SI to assess the condition of each of the AREEs The en JonmenS
med,a invert, gated included surface soil (0 to 2 ft below ground surface [bgs]), subsurface sTSft S
approximately 10 ft bgs), surface water, sediment, and groundwater. Analytical esults were comnareS t~o
background concentrations and regulatory screening levels to determine if environmentaTmed'a^ad been
" S'te aCtiVitieS' A brief deSCripti°n °f each of the five AREE* andthe
anmp « f P1f ^ 'n thS f°"OWin9 Para9raPhS- A detailed presentation of the samples c
and the analytical results can be found in the Phase I Reuse Area Rl Report (USAEC 1998) and the
AoFF14D (USEPA> on the final Pna*e I Reuse Area Rl Report and on the
AREE 14 investigation Summary Report (USAGE, 1998a) regarding these five AREEs along with the US
Army s responses are provided in Attachments 1 and 2, respectively.
AoFF14
AREE 14
Army s r
4.1 AREE 13 - Sludge Disposal Area
tmat Th! S'u,d91DisP°sal Area was used during the 1980s to dispose of sludges from the sewaae
treatment plant (STP) and the former STP, and sand filter sludge and sandblasting waste from the EteSnc
A™ E?* ?allty- 'I1 I'82' th* S'UdgeS WerS 3nalyZed for I0ta! metals and were'determ ed by th* u S
ftSh in 1 ggf'SiTf I* ^ HCI6?lyH T ;°f I3nd SPreading' ThS SlUd96 Pi'e Was 75 ft 'n Diameter and 3
ft high. In 1992, the U.S. Army decided to close the sludge pile, and twenty thousand cubic feet of
were excavated, moced with pressed sludge cake from the STP digester, and transport* to the
County Landfill. The area has been backfilled and seeded. *P°nea to cne
si *nri Ph«f f and Subsul1iac1e soil samP|es were collected at locations within the disposal area during the
SI and Phase I reuse area Rl. Iron (75,200 to 230,000 parts per million [pprn]) was the only analyte detec
' «*"* concentration (RBC) (23'°°° ppj) and
4.2 AREE 14 ~ Skeet Range
H fSf T ,Weekef]ds as a skeet ™9e between 1961 and 1994. The spent ammunition
of lead and steel shotgun pellets, was spread over the range and remains uncovered The skeet
range firing fan ,s oriented eastward in an 800-foot radius and is separated into the Hit and Miss Zones
«RnP'CS ?°J|ected from two 'options in the Miss Zone contained lead concentrations
nr TH , H " PPm) that exceeded the USEPA screening level for lead in residential soil of 400
ppm. The lead concentrations in the Hit Zone did not exceed the USEPA screening level for lead in resident
4.3 AREE 16-1- Possible Firefighter Training Pit
nf th > indicated that a Firefighter Training Pit was used at VHFS; however, the exact location
o the pit is not known with certainty. AREE 16-1 represents one possible location of the Firefighter Training
Pit. The Firefighter Training Pit was used monthly by the VHFS Fire Department for training in the mid-1970s
-s
aT rn HP rS app,roximate|y 50 ft in diam*er and 3 ft deep. During training activities, the pit was
,
mr 93S °dorant and then J9nited- Solvents and °ther combustible
materials may have also been used in the pit. In the mid-1980s, the pit was filled with VS-inch gravel
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Total petroleum hydrocarbon (TPH) field screening of the soil at AREE 16-1 was csrductec tc
delineate the area of contamination and to determine where soil samples should be collected' *cr scoratD-v
analysis Surface soil samples were collected based on positive TPH results from the field scree~"ig A-se-'c
(up *.o 21 6 ppm) exceeded its residential soil RBC (0.43 ppm) as well as its maximun- -acKgrojrc
concentration (4 89 ppm) in the surface soil samples collected at AREE 16-1. A number of c cxr.s-'fu'ars
ind.cative of combustion operations, were detected in the surface soil samples. 2.3.7,8-TCDD (2 "4E-04 ncr-
was the only dioxin/furan to exceed its residential soil RBC (4 3E-C6 ppm).
4.4 AREE 27 - AAFES Service Station
The AAFES Service Station (Building 238) was constructed in 1969 to provide fuel 3" serv ce for
VHFS personnel vehicles. The service station had underground storage tanks (USTs) for th-ee grades z*
gasoline, a pump area, and a service station area with two lifts. Drains ir the pump island ares -ead :c a grit
chamber, which discharges to a field north of the facility. In addition, a fenced storage area was located r
the rear of the facility for tires, batteries, and drums. Several gasoline, oil. and other spills we-e reported in
this area. In April. 1993, pressure testing of the regular unleaded gasoline pipeline confirmee a suspectec
leak. A 0,5-inch hole was found in the pipeline within the pump area. The corroded sectior. of pioe was
replaced, and the soils around the area where the leak occurred were excavated and then backfilled, The
system was re-tested to ensure no other leaks existed, and the pump was re-opened. Dunne tne SL~ner
and fall of 1993, field investigations confirmed soil and groundwater contamination due to :~s release of
gasoline from one or more leaking USTs and associated distribution piping The USTs were c:csed m jjne
1994. and removed in November, 1994. Operations at the AAFES Service Station were discc-t;nued ir the
fall of 1994, Contaminated soil removal and groundwater remediation activities at the AAFES Service Station
have been initiated and are being handled separately from the rest of AREE 27.
Surface and subsurface soil samples were collected from areas of potential contamination
downgradient from the discharge point of the grit chamber, at the service bay spill run-off area, and in the tire
storage area. Arsenic (up to 12.2 ppm) was found to exceed its residential soil RBC (0.43 ppm) and maximum
background concentrations (4.89 ppm surface soil and 5.4 ppm subsurface soil) in most of the surface and
subsurface soil samples. Lead was detected in a surface soil sample at the discharge point of the grit
chamber at a concentration of 1,200 ppm. which is three times the USEPA screening level of 40C ppm for lead
in residential soils. The maximum TPH concentration detected was 2,310 ppm, wh.ch is significantly higner
than the State's TPH soil action level of 100 ppm for UST sites, in the surface soil sample collected at the
discharge point of the grit chamber. TPH (737 ppm) was also detected above the State's TPH soil action ievei
lor UST sites in the surface soil at the service bay spill run-off area immediately off the parking cad. However.
TPH did not exceed the State's TPH soil action level for UST sites downhill from the grit chamber, further
along the spill run-off pathway, or in subsurface soils, indicating small localized areas of contamination. Other
than arsenic, none of the anatytes were found to exceed their associated screening levels in the subsurface
soil samples.
4.5 AREE 29-4 - Disposal Area
The Disposal Area is located near the northeast comer of VHFS, northwest of the Skeet Range
(AREE 14). Review of aerial photographs of this area provided evidence of disposal activities as early as
1958. These signs were visible to various extents as late as 1977. A total of five distinct areas were located
within the Disposal Area, based on ground stains and debris visible in aerial photographs. Two areas were
used for construction debris disposal and are now enclosed within groves of trees. Another area is an.
approximately 30-foot wide man-made depression in the ground where water collects after rain events. It is
not known whether the area was used to obtain fill material or for liquid disposal. The last two sites appeared
as orange-stained areas in historic aerial photographs.. These are both currently level and covered with grass
It is not known what materials, if any, were disposed in these areas.
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Surface soil samples were collected at the two construction debris piles and at the three other areas
of potential contamination. Aluminum {85,000 ppm), beryllium (2.15 ppm), and iron (160000 ppm)
concentrations in surface soil in the area of the former orange mound exceeded residential soil RBCs (78 000
ppm. 0.15 ppm. and 23,000 ppm, respectively) and maximum background concentrations (20 900 ppm 213
ppm, and 70.800 ppm, respectively). Benzo(a)pyrene (0.1 ppm). a polynuclear aromatic hydrocarbon {PAH'.
slightly exceeded its residential soil RBC (0.088 ppm) in one surface soil sample collected from the
construction debris areas. Arsenic (up to 13.6 ppm) exceeded its residential soil RBC (043 ppm) and
maximum background concentration (4.89 ppm) at the construction debris areas.
5.0 SUMMARY OF SITE RISKS
BRAs were conducted as part of the RIs 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:
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 ana
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 and Phase II reuse areas 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 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.
surface soil, surface water, and sediment. Potential risks to future excavation workers who could be exposed
to contaminants in subsurface soil were also evaluated in the HHRA. Subsurface soil was onJy evaluated for
excavation workers and not residents since residents would be unlikely to be exposed to subsurface soil. In
addition, 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 mixing of
subsurface soils with surface soil, clean topsoil, and other soil amendments. Therefore, it would not be
appropriate 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
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expressed as the probability that an individual will develop cancer from exposure to the contaminants from each
AREE Tne evaluation of noncarcmogenic effects is based on the hazard index (HI), which is the summation of
the HQs for mdivicual chemicals. The HQ is a comparison of chemical-specific chronic exposure doses with the
corresponding protective doses derived from health criteria. The USEPA recommends that remedial actions mav
be warranted at sites where the carcinogenic risk to any person is greater than 1 x10"5 or the HI is g reater thar
1 A carcinogenic risk of 1 x10J means that there is a potential of one additional person in a population of 10 GCC
deve.ccmg cancer fro-n exposure to contaminants at an AREE if tne AREE is net remediated. A HI greater tnar
1 ma.ca:es 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'
• Ecotoxicolooic 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 basec
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 and Phase II reuse areas 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 by 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 BRAs for the five AREEs are presented in the following paragraphs. A detailed
presentation of the BRAs can be found in the Phase I Reuse Area Rl Report (USAEC, 1998) and the Phase II
Reuse Area Rl Report (USAGE, 1999). available in the Information Repository.
5.1 AREE 13-Sludge Disposal Area
The HHRA determined that site-related contamination at AREE 13 does not pose an unacceptable
human health risk under either current industrial/commercial or potential future residential land-use conditions.
Discounting naturally-occurring metals that were statistically determined to be within background
concentrations, the highest estimated excess lifetime cancer risk (8x10"6) is for child residents exposed to
contaminants in surface soil by incidental ingestion, and the highest nopcarcinogenic risk (HI = 10) is for child
residents exposed to contaminants in surface soil by incidental ingestion. The contaminant that drove the
elevated HI at AREE 13 is iron. When site and background iron concentrations were statistically compared.
iron was not determined to be within background concentrations and, therefore, was not discounted. However.
iron was detected at comparable levels in similar subsurface soil types in background locations and is.
therefore, determined to be naturally-occurring and not site-related. An ERA was not conducted at AREE 13
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because all samples were collected at depths of greater than 6 inches. Based on these results, no action is
recommended at AREE 13.
5.2 AREE 14 - Skeet Range
The HHRA concluded that, under both current industrial/commercial and potential future residential
land-use conditions, site-related contamination -at AREE 14 does not pose an unacceptable human health risk.
except for lead 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 (4x10'6) is
for adult residents and child residents exposed to contaminants in surface soil by dermal absorption and
incidental ingestion, respectively; and the highest noncarcinogenic risk (HI = 0.8) is for adult residents
exposed to contaminants in surface soil by dermal absorption.
The human health risks associated with exposure to lead contamination in surface soil at AREE 14
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 lead levels of
toxicological significance for purposes of risk evaluation. The IEUBK Mode! run for AREE 14 predicted a
geometric mean blood lead level of 5.2 g/dL, with 7.75 percent of the population exceeding the blood lead level
of concern (10 g/dL). The USEPA currently finds 5 percent of the population exceeding the blood lead level
of concern acceptable. Therefore, the IEUBK Model results indicate that if AREE 14 was developed for
residential use in the future, the lead concentrations in the surface soil may be a potential problem for young
children.
The potential adverse effects to child residents were driven by the presence of lead above the USEPA
screening level for lead in residential soil of 400 ppm at two locations in the Miss Zone. The extent of lead
contamination in the two locations that drove unacceptable human health risks was further investigated during
the SRI. Soil in those two locations was excavated and disposed off site, and the sample results from the
remaining soil show that lead concentrations do not exceed the USEPA screening level for lead in residential
soil. Thus, no action is recommended at AREE 14 because the unacceptably high lead concentrations were
removed during the SRI. A detailed presentation of the investigation of lead hot spots at AREE 14 can be
found in the SRI Report, available in the Information Repository.
The ERA determined that surface soil at AREE 14 does not pose significant potential adverse
ecological effects.
Based on these results, no action is recommended for AREE 14.
5.3 AREE 16-1 - Possible Firefighter Training Pit
Results of the HHRA indicate that, under both current industrial/commercial and potential future
residential land-use conditions, the risks to workers, trespassers, and residents are acceptable for exposure
to site-related contaminants (i.e., arsenic and 2,3,7,8-TCDD) 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 (9X10'5) is for adult residents and child residents exposed to site-related
contaminants in surface soil by dermal absorption and incidental ingestion, respectively; and the highest
noncarcinogenic risk (HI = 1) is for child residents exposed to site-related contaminants in surface soil by
incidental ingestion. Although the total HI equals 1, the His recalculated by target organ/critical effect are all
less than 1. No significant potential for adverse ecological effects were found in the ERA. Based on these
results, no action is recommended at AREE 16-1.
-------
5.4 AREE 27 - AAFES Service Station
Results of the HHRA suggested that site-related contamination at AREE 27 does not sose ar
unacceptable human health risk under either current industrial/commercial or potential future residents! la-^c-
use conditions, Discounting naturally-occurring metals that were statistically determined to be .v:t~.:-
background levels the highest estimated upper-bound excess lifetime cancer risk (7x10's) is for child residents
exposed to contaminants in surface soil by dermal absorption, and the highest noncarcinogenic risk 'HI = 2 •
is for child residents exposed to site-related contaminants in surface soil by dermal absorption When
recalculated by target organ/critical effect, the HI equals 1.3 for the kidneys, primarily as a result of exposures
to chromium in surface soil at AREE 27. Although not all chromium present at AREE 27 will be hexavaiert
chromium (i e , the most toxic form of chromium), the conservative toxicity criterion for hexavalent chrorrvjn
was used in the HHRA. Therefore, a HI of 1.3 calculated using conservative toxicity criteria is considered
acceptable. Although arsenic exceeds its residential soil RBC, it was not a risk driver at AREE 27
Lead contamination in surface soil at AREE 27 was evaluated using the IEUBK Model, as explained
in the AREE 14 discussion, which predicted a geometric mean blood lead level of 3.2 ug/dL, with 0.77 percent
of the population exceeding the blood lead level of concern (10 ug/dL). Again, the USEPA currently finds 5
percent of the population exceeding the blood lead level of concern acceptable.- Therefore, the surface soil
tead concentrations at AREE 27 are unlikely to have an adverse effect on the exposed child resident
population.
The ERA determined that site-related contaminants at AREE 27 posed no significant potential for
adverse ecological effects.
Based on these results, no action is recommended at AREE 27.
5.5 AREE29-4-DisposalArea
The HHRA determined that site-related contamination at AREE 29-4 does not pose an unacceptable
human health risk under either current industrial/commercial or potential future residential land-use conditions.
Discounting naturally-occurring metals that were statistically determined to be within background
concentrations, the highest estimated upper-bound excess lifetime cancer risk (3x10'5) is for child residents
exposed to contaminants (i.e., benzo[a]pyrene and aluminum) in surface soil by incidental ingestion. and the
highest noncarcinogenic risk (HI = 1) is for child residents exposed to site-related contaminants in surface soil
by incidental ingestfon. The ERA concluded that significant potential adverse ecological effects are not posed
by the site-related contaminants at AREE 29-4. Based on these results, no action is recommended at AREE
29-4.
6.0 SELECTED ALTERNATIVE
No action is selected by the U.S. Army for AREEs 13,14,16-1,27. and 29-4 because these sites do not
pose unacceptable human health or ecological risks. USEPA and the Virginia Department of Environmental
Quality (VDEQ) concur with this decision. The estimated cost to implement this alternative is SO.
7.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION
The Proposed Plan for AREEs 13. 14, 16-1. 27, and 29-4 was released to the public on or about
March 31.1999 (see Attachment 3). This document was made available for public review in the Information
Repository at the following location:
10
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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 notice of availability of the Proposed Plan (see Attachment 4) was published in The Fauquier
Citizen, the Fauquier Times-Democrat, and the Manassas Journal Messenger during the week of March 29.
1999. A public comment period was held from April 1, 1999, through April 30, 1999. In addition, a public
meeting was held on April 15. 1999, to present the Proposed Plan for AREEs 13, 14, 16-1, 27, and 29-4 and
to answer questions and receive public comments. The public meeting minutes have been transcribed, and
a copy of the transcript is available to the public at the aforementioned location. A Responsiveness Summary.
included as part of this Decision Document (DD), has been prepared to respond to the significant comments.
criticisms, and new relevant information received during the comment period. Upon signing the DD, the U.S
Army will publish a notice of availability of this DD in The Fauquier Citizen, the Fauquier Times-Democrat, and
the Manassas Journal Messenger, and place the DD in the information Repository.
8.0 RESPONSIVENESS SUMMARY
The purpose of this Responsiveness Summary is to provide the public with a summary of citizen'
comments, concerns, and questions about AREEs 13, 14, 16-1, 27, and 29-4. A public meeting was held on
April 15, 1999, to present the Proposed Plan and to answer questions and receive comments. At the public
meeting, one citizen had a question regarding the Proposed Plan. No written public comments were received
during the April 1, 1999, through April 30, 1999, public comment period. Written comments, however, were
received from US EPA.
The Responsiveness Summary is divided into the following sections:
• Selected newspaper notices announcing dates of the public comment period and location and
time of the public meeting;
• Comments raised during the public meeting on April 15, 1999;
• Public meeting attendance roster;
• Restoration Advisory Board Members; and
• Written comments received during the public comment period.
All comments and concerns summarized in .this document have been considered by the U.S. Army in making
a decision regarding the selected alternative.
8.1 Selected Newspaper Notices
A public notice announcing the availability of the Proposed Plan and the public meeting was published
in The Fauquier Citizen, the Fauquier Times-Democrat, and the Manassas Journal Messenger during the
week of March 29, 1999. This public notice is provided in Attachment 4.
11
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8.2 Comments Raised During the Public Meeting on April 15,1999
' One citizen raised a comment during the public meeting. The citizen's question and the U.S Army's
response are presented below:
CONCERNED CITIZEN: Is the chromium at AREE 27 going to present a hazard to the water source used >"
the pcol?
ARMY RESPONSE: No. the chromium is present at very low levels that may actually be indicative c*'
background cnromium levels and thus would not impact the water source for the pcol
8.3 Public Meeting Attendance Roster
The public meeting was held on April 15. 1999. at the Former Headquarters Conference Room
(Building 101) at VHFS. The members of the community that attended the public meeting included Pat White
Mary Noel McMullen, and William McMullen (see Attachment 5).
[
8.4 Active Restoration Advisory Board Members
1. Chris Kencik
2 Dean Eckelberry
3 John Mayhugh
4. Owen Bludau
5. Tim Tarr
6. Kevin Bell
7. Steve Mihalko
6, Robert Stroud
9. Joe Phelan
8.5 Written Comments Received During the Public Comment Period
No written comments were received from citizens during the public comment period. Written
comments were received from USEPA during the public comment period and are provided in Attachment 5.
The U.S, Army's responses to these comments are also provided in Attachment 6 and were distributed to the
public during the public comment period. Most of USEPA's comments suggested wording changes or
requested clarification regarding specific information. Wording changes and clarifications requested by USEPA
(see Attachment 6 for details) have been incorporated into this DD.
The USEPA offered a comment regarding the appropriateness of decision-making .based on the draft
SRI Report The SRI was conducted to fill data gaps identified in the R!s (e.g., the extent of contamination at
AREE 14). The SRI Report does not include risk assessment All risk conclusions were made based on the
RIs. Therefore, the status of the SRI Report has no impact on the no action decision made for AREEs 13.14
16-1.27. and 29-4.
9.0 REFERENCES
U.S. Army Corps of Engineers (USAGE). 1998a. AREE 14 Investigation Summary Report. Vint Hill Farms
Station. Draft Document Prepared by ICF Kaiser Engineers, Inc. Edgewood, Maryland. June. 1998
12
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U.S. Army Corps of Engineers (USAGE). 1998b. Supplemental Remedial Investigation Report. Vint Hill Farms
Station. Draft Document. Prepared by ICF Kaiser Engineers, Inc. Edgewood, Maryland. November
1998.
U.S. Army Corps of Engineers (USAGE). 1999. Remedial investigation Report. Vint Hill Farms Station Phase
II Reuse Area Remedial Investigation. Final Document. Prepared by ICF Kaiser Engineers, Inc
Edgewood, Maryland. January, 1999.
U S. Army Environmental Center (USAEC). 1996. Site Inspection Report with Supplemental Hydrogeologic
Investigation. Vint Hill Farms Station. Warrenton, Virginia. Final Document. Prepared by Science
Applications International Corporation, McLean, Virginia. June, 1996.
U.S. Army Environmental Center (USAEC). 1998. Remedial Investigation Report. Vint Hill Farms Station
Phase I Reuse Area Remedial Investigation/Feasibility Study. Final Document. Prepared by ICF
Kaiser Engineers, Inc. Edgewood, Maryland. April, 1998.
13
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ATTACHMENT 1
RESPONSE TO USEPA COMMENTS ON THE
FINAL PHASE I REUSE AREA Rl REPORT
-------
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1 Response to Comments on the
Final Phase I Reuse Area RI Report, Vint Hill Farms Station
from USEPA Region III
RESOLUTION OF PREVIOUS COMMENTS
BT "
Comment
Response:
Regarding data validation, please explain why no J, K, or L qualifiers appear on any of the
data. Since there was a discrepancy between the IRDMIS database and the SI report for
AREE 11 P'eaSe indi°ate the meth°d US6d WhSn determinin9 accurate results for
Since the data qualifiers had to be hand entered, only the qualifiers that affect the risk
assessment and, therefore, the conclusions of the Phase I Reuse Area RI Report were
entered into the database and presented in the report.
Since the Site Inspection (SI) Report was supposedly prepared using the IRDMIS
database, the IRDMIS database information was used when a discrepancy was found
between the IRDMiS database and the SI Report V
IMPACT OF NEW TOXICITY FACTORS ON RISK AT PHASE I
NOTE:
The complete text of USEPA's comments including point-by-point impacts of the toxicity
factor changes are provided in Attachment 1 to these responses. USEPA's comments are
summarized herein to focus attention on the overall conclusions made by USEPA
regarding the impact of the toxicity factor changes on the Final Phase I Reuse Area RI
Report recommendations.
Comment:
Toxicity factors for some chemicals have changed since April, when this report was
submitted. In most cases, the changes would not alter the outcome of the risk
assessment. However, in a few cases, the impacts on risk-management decisions could
oe significant. As we discussed during our conference call on December 2 1998 in
cases where toxicity factors could possibly change risk decisions a technical memo will
ce developed that rationalizes no further action decisions at selected AREEs This
technical memo should include rationalizations for AREEs 12 13 16-1 27 29-4 and
groundwater wells that reveal high levels of bis(2-ethylhexyl)phthalate (BEHP).'
a) For AREE 12 subsurface soil, future residential risks did exceed 1E-4 due to
benzo[a]pyrene.
b) For AREE 13, aluminum, iron, and possibly vanadium also contributed.
c) For AREE 16-1 surface soil, risks did exceed NCP targets, due to arsenic, TCDD
and chromium. The concentrations of arsenic and TCDD at AREE 16-1 pose a
total cancer risk of 2E-4 for the child/adult scenario. Chromium is a possible
driver of an HI above 1.
DACA31-94-D-0064
ESPS4-81
January 1999
Response to USEPA Comments
Final Phase I Reuse Area RI Report
Vint Hill Farms Station
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For AREE 27, chromium and cadmium contribute to an HI above 1.
e) For AREE 29-4 surface soil, the aluminum HI of 1.4 was borderline. '
f) For site-wide groundwater, the BEHP is a potential concern. Although phthalates
are common laboratory contaminants, BEHP was detected in several wells at
high levels that were not attributed to blank contamination. On the other hand,
the presence of BEHP in background wells at similar levels implies that there may
be a regional BEHP issue. As a base-closure issue, the groundwater BEHP
could be important, since it exceeds both NCP target risks and the MCL.
Response: The U.S. Army appreciates USEPA's assessment of risks for the Phase I reuse area
based on the recent toxicity factor changes. However, for the record, the U.S. Army
cannot agree with the details of USEPA's assessment and the risk numbers presented
without conducting the assessment itself. Reassessment of risks is not productive since
the report is final based on the toxicity factors valid at the time the report was finalized
and requested by USEPA in its comments on the Draft Phase I Reuse Area Rl Report.
Therefore, rather than addressing the specific numbers presented in USEPA's comments,
the goal of these responses is to address the major conclusions made by USEPA during
its assessment of the toxicity factor changes.
It is important to note that the toxicity factors used in USEPA's assessment were not
available at the time the Phase I Reuse Area Rl Report was being finalized and the
reme'diation decisions were being made. Rather, the Phase I Reuse Area Rl Report was
prepared, and the remediation decisions made, based on the toxicity factors that were
valid at the time (i.-e.. toxicity factors published in October, 1997}. However, in light of the
recent toxicity factor changes, the U.S. Army still believes that the no further action
conclusions made in the Final Phase 1 Reuse Area Rl Report are protective for the five
AREEs identified in USEPA's comments and site-wide groundwater as discussed in the
following paragraphs.
a) For AREE 12 (Dump #2) subsurface soil, the no further action decision is
protective for two reasons. First, USEPA has previously established a policy
position that only industrial exposures (i.e., construction workers) be considered
when evaluating soils below 2 ft below ground surface (bgs). Therefore, the
observation made by the USEPA toxicologist that the recently published toxicity
factor changes cause future residential risks from exposure to subsurface soil at
AREE 12 to exceed 1E-4 due to benzo[a]pyrene is not relevant: Construction
worker exposures remain below the target risk levels even in light of the recent
toxicity factor changes. Second, it is important to note that AREE 12 is a
permitted construction debris landfill, and the U.S. Army intends to institute deed
restrictions which will prevent exposure to subsurface soil.
b) For AREE 13 (Sludge Disposal Area), USEPA identified aluminum, iron, and
possibly vanadium as compounds that contribute to elevated non-carcinogenic
risk. As discussed in Section 8 of the Final Phase I Reuse Area Rl Report, the
soil samples from AREE 13 were collected from 1-3 ft bgs which straddles the
surface/subsurface soil boundary (i.e., 2. ft bgs). To be conservative, these
samples were evaluated as surface soil samples in the Human Health Risk
Assessment (HHRA) and thus were statistically compared to surface soil
background results which, are based on samples collected from 0-0.5 ft bgs.
However, a more appropriate comparison can be made using the background
DACA31-94-D-0064
ESPS4-81
January 1939
Response to USEPA Comments
Final Phase I Reuse Area Rl Report
Vint Hill Farms Station
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subsurface soil sample results since surface soil was likely removed alona with
the sludge in 1992. Iron concentrations in background subsurface soil samcles
are highly variable, ranging from 9,360 ug/g to 180,000 ug/g Aluminum
concentrations in background subsurface soil samples range from 4 410 uq/q to
60,600 ug/g, and vanadium concentrations in background subsurface soil
samples range from 44.3 ug/g to 531 ug/g. The variability of iron, aluminum and
vanadium concentrations in the background subsurface soil samples is most
likely due to the variability of soils that were sampled. The composition of soil is
primarily controlled by the composition of the bedrock from which it is formed
Figure 2-1 of the Final Phase I Reuse Area Rl Report shows the geoloqv of
shallow bedrock across VHFS. For example, the background subsurface soils
which have the highest-iron concentrations (SB-BK-002 [91 000 ug/g at 3 ft basl
and SB-BK-003 [180,000 .ug/g at 5 ft bgs and 100,000 ug/g at 18 5 ft bgsl) are
located in areas where intrusions of mafic material (i.e., basalt) have occurred
Mafic rocks are rich in iron and magnesium and will produce soils that are rich in
iron and magnesium. Iron concentrations in soil at AREE 13 range from 75 200
ug/g to .230,000 ug/g. According to the Environmental Contamination Survey
(USATHAMA, 1986), a mafic intrusion (Hickory Grove Basalt) bisects AREE 13
and the sludge disposal area lies over the geological contact area of the
Catharpm Creek Member and the Hickory Grove Basalt. The high iron
concentrations are most likely a product of the parent material from which the soil
in this area is derived. In addition, it should be noted that the aluminum and
vanadium concentrations at AREE 13 (53,300 ug/g to 73,100 ug/g for aluminum
and 221 ug/g to 317 ug/g for vanadium) are more comparable to the subsurface-
soil background ranges than they are. to the surface soil background ranges
Furthermore and more importantly, aluminum, iron, and vanadium are not
anticipated to be present in environmental media at AREE 13 based on site
history. Other metals (e.g., silver, cadmium, lead, and mercury) which are more
likely to be site-related contaminants based on site history were either not
detected or were detected at concentrations below screening levels Therefore
aluminum, iron, and vanadium are not site-related contaminants but rather are
representative of background concentrations in soil derived from the type of
bedrock present at AREE 13. No further action is a protective recommendation
for AREE 1-3.
c) For AREE 16-1 (Possible Firefighter Training Pit) surface soil, USEPA found that
the concentrations of arsenic and TCDD pose a total cancer risk of 2E-4 for the
child/adult scenario. Even when ingestion and dermal absorption exposure routes
are added as was done by USEPA, the cancer risk is borderline compared to the
target risk of 1E-4. Based on the borderline cancer risk associated with arsenic
and TCDD, the small size of the firefighter training pit (i.e., 50 ft diameter for one
of the possible pits which was most likely AREE 16-2 based on terrain) for which
typical exposure assumptions are exaggerated, and the uncertainty that AREE
16-1 truly represents a former firefighter training pit, no further action at AREE 16-
1 is protective.
USEPA also found that chromium is a possible driver of a HI above 1 given the
recently lowered (i.e., more stringent) toxicity factor for hexavalent chromium. It
should be noted that there is a great deal of conservatism built into the calculation
of the HI for chromium in surface.soil at AREE 16-1 for the following reasons: 1)
' tne HHRA is based on the conservative assumption that ail chromium present at
ESPS4-81 • ' 3 Response to USEPA Comments
January 1999 Final Phase I Reuse Area Rl Report
Vint Hill Farms Station
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£REE 1,6;1 ' f XK3V chromium whjch is not supported by site history; and 2)
. the oral RfD for hexavalent chrom.um has an uncertainty factor of 900. which
indicates high uncertamty associated with the RfD. Hexavalent chromium is
typ.cally found ,n the environment as a result of contamination from electroplating
or conversion coatmg operations where hexavalent chromium is used in the
process solutions. The residential soil risk-based concentration (RBC) for trivalent
chromium the form of chromium more commonly found in the environment when
electroplating and conversion coating operations are not involved is three orders
of magnitude higher (i.e., less stringent) than the corresponding RBC for
hexavalent chromium (i.e.. 1.2E5 pg/g versus 2.3E2 M/g). In the case of AREE
16-1, which was a possible firefighter training pit, operations that used hexavalent
chromium were not conducted. In fact, operations using chromium in any form
were not conducted.
In addition although chromium at AREE 16-1 was not statistically within
background, the data do not suggest widespread chromium contamination that
would be present if the contamination was site-related. Four surface soil samples
were collected at AREE 16-1 and yielded chromium at concentrations ranging
from 27.2 ng/g to 59.9 ug/g, with an arithmetic mean concentration of 41 0 ug/g
Background concentrations in surface soil were detected at concentrations as
high as 60 ug/g. A common sense review of the data in light of site history
md.cates that it is reasonable to find the chromium concentrations to be
representative of background concentrations,
Based on the conservatism of the HI calculation for chromium the lack of site
history involving chromium, and the fact that the detected chromium levels are
potential background levels, the no further action decision for AREE 16-1 is
protective. •
d) For AREE 27 (AAFES Service Station) surface soil, although cadmium and
chromium both contribute to a HI above 1. chromium is the risk driver because of
the recently lowered (i.e.. more stringent) toxicity factor for hexavalent chromium
Therefore, this response focuses on chromium. As discussed in Section 8 of the
Final Phase I Reuse Area RI Report, there is a great deal of conservatism built
into the calculation of the HI.for chromium in surface soil at AREE 27 for the
following reasons: 1) the HHRA is based on the conservative assumption that all
chromium present at AREE 27 is hexavalent chromium which is not supported by
site history; and 2) the oral RfD for hexavalent chromium has an uncertainty
factor of 900. which indicates high uncertainty associated with the RfD
Hexavalent chromium is typically found in the environment as a result of
contamination from electroplating or conversion coating operations where
. hexavalent chromium is used in the process solutions. The residential soil RBC
for tnvalent chromium, the form of chromium more commonly found in the
environment-when electroplating and conversion coating operations are not
involved, is three orders of magnitude higher (i.e., less stringent) than the
.corresponding RBC for hexavalent chromium (i.e., 1.2E5 pg/g versus 2 3E2
ug/g). In the case of AREE 27, which was a fuel and service station, operations'
that used hexavalent chromium were not conducted. In fact, operations using
chromium in any form were not conducted.
In addition, although chromium at AREE 27 was not statistically within
background, the data do not suggest widespread chromium contamination that
DACA31-34-D-0064 ~~~ 1 ~ ~~~ —
ESPS4-81 Response to USEPA Comments
January 1999 . Final Phase' Reuse Area RI Report
Vint Hill Farms Station
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would be present if the contamination was site-related. Nine surface soil
were collected at AfcEE 27 and yielded chromium at concentrations rangngom
24.8 ng/g to 75.5 jig/g, with an arithmetic mean concentration of 40 6 ua/a
Background concentrations in surface soil were detected at concentrations as
nigh as 60 jig/g. A common sense review of the data in light of the site history
indicates that it is reasonable to find the chromium concentrations to be
representative of background concentrations.
Based on the conservatism of the HI calculation for chromium, the lack of site
history involving chromium, and the fact that the detected chromium levels are
potential background levels, the no further action decision for AREE 27 k
protective.
F?!i ^RELE ?9'4 (DisP°sal Area> surface soil, USEPA calculated a HI for aluminum
of 1.4 which they acknowledge is borderline. Based on the fact that the oral RfD
for aluminum has an uncertainty factor of 100 and the HI is not significantly
different from 1 even when ingestion and dermal absorption exposure routes are
added, no further action at AREE 29-4 is protective. -
For site-wide groundwater, the fact that BEHP is both a common laboratory
contaminant and a common field contaminant is an important point Although it is
true that not all BEHP detections were blank qualified, the primary source of
O!L]£ !S samP|in9 equipment in combination with the sampling technique
pluo 'S U$fd as a P|astici2er in tne flexibie tubing used to sample the wells'
BEHP was detected in the equipment blanks prepared in the field at lower levels
than was found in some of the groundwater samples primarily because of how the
equipment blanks were prepared versus how the groundwater samples were
collected. In the preparation of the equipment blanks, water was pumped through
he sample tubing at a comparatively rapid rate which did not allow for significant
leaching and accumulation of BEHP in the sample. Conversely the low-flow
groundwater monitoring well sampling method involved pumping of groundwater
through the sample tubing at low flow rates. Many of the monitoring wells were
slow producers and required pumping at very low flow rates. The low flow of
water through the sample tubing during groundwater sampling increased the
opportunity for BEHP to leach into the sample and concentrate. This finding is
supported by the fact that elevated BEHP was found in site wells and background
wells at similar levels. Neither site nor regional history support USEPA's
suggestion that the BEHP found in the groundwater samples may represent a
regional issue. Groundwater samples were analyzed for a wide range of
constituents, and BEHP was the only constituent that exceeded screening levels
in most of the wells. If the BEHP were the result of site or regional groundwater
contamination, it would have been found in combination with other contaminants
rather than alone. Therefore, the conclusion that the BEHP is present as a result
of field contamination is appropriate, and no further action is a protective
recommendation for site-wide groundwater at VHFS.
ESPS4-81 5 Response to USEPA Comments
January 1999 Final phase ' Reuse Area Rl Report
Vint Hill Farms Station
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OTHER RISK-RELATED ISSUES
Comment: Cancer risks were presented separately for children and adults. In order to estimate the
lifetime cancer risk when exposure includes both childhood and adulthood the risks
would be:
(Adult cancer risk x 24/30) + (Child cancer risk).
Response: Remediation decisions have all been made based on separate adult and child exposures
since this comment had not been made until well into the decision-making process (i e
after the Final Phase I Reuse Area Rl Report was submitted). Furthermore this
methodology is consistent with that used in other HHRAs performed for and accented bv
USEPA Region III.
\^o^^sni'2.\-^^''l^^^^^^^^}^^.'!^ji^^i^^^^
Comment: The soil-to-skin adherence factors are generally reported at lower levels in the new
Exposure Factors Handbook than previously (Section 7.1.2.3; Tables 7-16, 7-17, 7-19, 7-
24). Therefore, it is possible that dermal soil risks are overestimated in this respect.
Response: The uncertainty associated with the soil-to-skin adherence factors and their impar-t on risk
estimates is already discussed in the Uncertainty Section of tne Final Phase I Reuse Area
Rl Report.
DACA31-94-D-Q064
ESPS4-81
January 1999
Response to USEPA Comments
Final Phase I Reuse Area Rl Report
Vint Hill Farms Station
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ATTACHMENT 1
DETAILED COMMENTS FROM USEPA REGARDING NEWTOXICITY FACTORS
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IMPACT OF NEWTQXICITY FACTORS ON RISK AT PHASE I
Toxicity factors for some chemicals have changed since .April, when this report was submitted. In most
cases, the changes would not alter the outcome of the risk assessment. However, in a few cases, the
impacts on risk-management decisions could be significant. As we discussed during our conference call
on December 2, 1998, in cases where toxicity factors could possibly change risk decisions a technical
memo will be developed that rationalizes no further action decisions at selected AREEs. This technical
memo should include rationalizations for AREEs 12. 13, 16-1, 27, 29-4 and groundwater wells that reveal
high levels of BEHP. To assist in the facilitation of this memo, EPA has provided a table in this letter that
indicates the impacts of the toxicity changes on the final estimates of risk. The toxicity-factor changes
would also impact other tables and sections of the Rl, on which the final risk estimates are built. For
informational purposes, the changes to those "building-block," non-summary sections are included in an
attachment to this letter.
1. Table 7-155 (and pages 7-62 to 7-73):
The table should not be split by route; total risks are more informative. Also, given the changes
noted in the attachment, the risks on this table would be as follows:
MEDIUM/
LOCATION
WORKER
CA. RISK
WORKER
Hi
ADULT
RES.
CA.
RISK
ADULT
RES.
HI
CHILD
RES.
CA. RISK
CHILD
RES.
HI
SURFACE SOIL:
AREE9
AREE 1 1
AREE 13
AREE 16-1
AREE 16-2
AREE 17
AREE 18
AR'EE 19
AREE 21
AREE 24
AREE 27
AREE 29-2
AREE 29-3
AREE 29-4
Groundwater
—
3E-5
—
-
—
—
—
—
-
—
—
—
—
—
—
—
1.6 c
1.7 c
1.3
—
--
—
— -
—
—
—
—
-
2.3 a
-
-
7E-5
—
1E-4 '
—
-
—
-
—
— -
—
—
—
—
6E-4
1.9 c
4 a
4
2.7 a
—
2c
2c
2.4 c
1.6 c
2.2 c
3
1.4 c
-
5a
8
-
5E-5
-
1E-4
—
-
-
—
—
—
—
-
„
—
3E-4
6.5 a
11
14
8
3.6 a
3 a
6a
7
6a
7a
7.5
4.3 a
3.1 c
16
18
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MEDIUM/
LOCATION
WORKER
CA. RISK
SEDIMENT:
EASTERN
NORTHERN
WESTERN
AREE 12
Central AREEs
AREE 27
SUBSURFACE SOIL:
b)
c)
d)
e)
(Footnotes have the same meaning as in the orig rial table.)
2, The conclusions on page 7-63 should be altered slightly:'
a) Add AREE 12 subsurface soil, benzo[a]pyrene.
Add AREE 29-4 surface soil, aluminum.
Add AREE 16-1 surface soil, arsenic, TCDD, and chromium.
To AREE 13, add aluminum and possibly vanadium.
To AREE 27, add cadmium.
3. Table 8-1:
a) For AREE 12, future residential risks did exceed 1E-4 due to benzo[a]pyrene
b)
. c)
d)
e)
0
aue to
2?l ca.d^ium was'also a contributor. The reason for no remediation given the
yes in unacceptable health risks, is not clear. 9
For AREE 29-4. the aluminum HI of 1 .4 was borderline.
For site-wide groundwater, the bis(2-ethylhexyi)Phthalate (BEHP) is a potential concern
Reported levels were not all attributed to blank contamination. P°ien«a' concern.
4.
s AREF H' AREE 16'1 Surface '
soil. AREE 13 iron, aluminum, and vanadium (as elevated metals in a sludge
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disposal area), and AREE 27 (for which the increase in the chromium toxicity factor has increased
the HI, although the point about valence state is well taken).
5. Section 8.2 should not dismiss the BEHP lightly. Although phthalates are common laboratory
contaminants, BEHP was detected in several wells at high levels that were not attributed to blank
contamination. On the other hand, the presence of BEHP in background weiis at similar levels
implies that there may be a regional BEHP issue. As a base-closure issue, the groundwater
BEHP could be important, since it exceeds both NCP target risks and the MCL.
6. Page ES-2: For AREE 12, subsoil cancer risks exceed 1E-4 for potential residential exposure.
For AREE 13. it is not clear that no action should be taken for metals exceeding background
levels in a sludge disposal area.
7. Page ES-3:
a) The concentrations of arsenic and TCDD at AREE 16-1 pose a total cancer risk of 2E-4
for the child/adult scenario. Chromium is a possible driver of an HI above 1. Therefore, i;
is not clear that no action is appropriate.
b) For AREE 27, chromium and cadmium contribute to an HI above 1.
8. Page ES-4:
a) For AREE 29-4, the aluminum HQ is 1.4.
b) For groundwater, further consideration should be given to the BEHP results.
c) For the summary bullets, antimony and arsenic should be added to AREE 19. AREE 13
(aluminum, iron, and possibly vanadium) should be added. AREE 16-1 (arsenic, TCDD.
and chromium) should be added. AREE 29-4 (aluminum) and AREE 12 subsurface soi;
(benzofalpyrene) may warrant inclusion. Groundwater BEHP should receive further
consideration. AREE 27 (cadmium and chromium) may warrant inclusion.
OTHER RISK-RELATED ISSUES
9.' Cancer risks were presented separately for children and adults. In order to estimate the lifetime
cancer risk when exposure includes both childhood and adulthood, the risks would be:
(Adult cancer risk x 24/30) + (Child cancer risk).
10. Appendix F: This appendix generates residential risks, but uses industrial RBCs to screen. If
residential RBCs were used, then additional COPCs (with their EPCs shown here) would be
identified:
AREE 12: aluminum (16100 mg/kg), chromium (24.7 mg/kg), iron (40400 mg/kg), manganese
(605 mg/kg), vanadium (95 mg/kg)
Central AREEs: aluminum (18900 mg/kg), antimony (0.27 mg/kg). cadmium (0.4 mg/kg).
chromium (27 mg/kg), manganese(2390 mg/kg), silver (0.44 mg/kg), vanadium (110 mg/kg)
AREE 27: aluminum (15000 mg/kg), arsenic (12.2 mg/kg). chromium (46 mg/kg), iron (48000
mg/kg), manganese (950 mg/kg), vanadium (116 mg/kg)
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11.
S.','£
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ATTACHMENT: DETAII s ON RISK ASSESSMENT SECTIONS IMPACTED BY NEW TQXIC1TY
FACTORS : ;
1. Tables 4-2 and F-1: Screening RBCs for beryllium, chromium, vinyl acetate, 1,3-dichlorobenzene,
2-chloronaphthalene, bis(2-chloroethyl)ether, dibenzofuran, 2-rnethylnaphthalene, naphthalene,
the chlordanes, toxaphene, dinosefa, and Aroclor 1016 have been updated. As will be seen, only
the differences for beryllium, chromium, and chlordane are generally significant for Vint Hill.' The
1,2,3,7,8-PeCDF RBCs were incorrect on this table. However, since the correct numbers were
used elsewhere in the report, this is not a major issue.
2. Beryllium's RBC would be higher and it would no longer be a COPC, and chromium's RBC would
be lower but its COPC status would not change, on Tables 4-3 through 4-6, Tables 5-2 through 5-
9, Table 5-10 (chromium only), Table 5-11, Table 5-12, Tables 5-15 through 5-23, Tables 5-25
through 5-30, Tables 5-33 through 5-43, Table 5-45, Table 6-1, Table 7-2, and in Sections 4.2 1
4.2.2. 4.2.3. 5.1.2, 5.1.4, 5.2.2, 5.2.4. 5.2.5, 5.3.2.1, 5.3.2.2, 5.3.4.1. 5.3.4.2, 5.4.4, 5.5.1, 5742'
5.7.5.2, 5:8.4.1, 5.8.4.2, 5.9.2, 5.9.4, 5.10.4.1, 5.10.4.2, 5.10.5, 5.11.2, 5.11.3, 5.12.1, 5142'
5.14.4. 5.15.4, 5.16.2. 5.17.4. 5.18.2. 5.18.4, 5.18.5, 5.19.2, 5.19.4, 5.19.5, 6.4.1.1, 6.4.2.1, and
7.1.1.4; also on page 7-6, 3rd paragraph.
2-Methylnaphthalene's RBC would be lower, but its COPC status would not change, on Tables 5-
2, 5-9, 5-19, 5-35, 5-41, 5-45, and 7-2^ and in Sections 5.1.2, 5.3.4.1, 5.3.4.2 5841 5 144
5.18.4, 5.18.5, 5.19.4, and 5.19.5. >
Chlordane's RBC would be higher, but its COPC status would not change, on Tables 5-7. 5-11, 5-
20. and 5-43, and in Sections 5.3.2.1, 5.3.2.2, 5.4.4, 5.8.4.2, 5.19.2, and 5.19.5. The COPC
status of total chiordane would not change on Tables 5-8 and 5-9, and in Sections 5.3.4.1 and
5.3.4.2. Chlordane would no longer be a COPC on Table 5-19 and in Section 5.8.4.1.
Naphthalene's RBC would be lower, but its COPC status would not change, on Tables 5-8, 5-9, 5-
11, 5-19. 5-41, 5-42, 5-45, and 7-2. and in Sections 5.3.4.1, 5.3.4.2, 5.4.4, 5.8.4.1, 5.18 45185
5.19.4. and 5.19.5.
3. On Tables 7-4 and 7-11 (also pp. 7-7 through 7-10), the COPC selections would change as
follows:
AREEs 9, 13, 19, 21,24, 29-2. 29-3: beryllium no, chromium yes;
AREEs 11, 16-1, 16-2, 18. 27. 29^4: beryllium no;
AREE 17: chlordane no. beryllium r o. chromium yes.
4. On Tables 7-6 and 7-11 (also on p. 7-12}. the COPC selections for occupational use would
change as follows: Central AREEs: beryllium no.
5. On Tables 7-8 and 7-11 (also on p. 7-12), the COPC selections would change as follows:
chlordane no.
6. On Tables 7-10 and 7-11 (also on pp. 7-13 and 7-14), the COPC selections would change as
follows:
Eastern: beryllium no;
Northern: beryllium no, chromium yes;
Western: alpha-chlordane no. gamma-chlordane no, beryllium no.
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7. Table 7-14:
^
Surface soil, AREE 13: Chromium should be added, with an EPC of 28;9 mg/kg.
Surface soil, AREE 17: Chromium should be added, with an EPC of 35 mg/kg.
Surface soil, AREE 19: Chromium should be added, with an EPC of 23 mg/kg.
Surface soil, AREE 21: Chromium should be added, with an EPC of 20 mg/kg.
Surface soil, AREE 24: Chromium should be added, with an EPC of 33.6 mg/kg.
Surface soil, AREE 29-2: Chromium should be added, with an EPC of 36.6 mg/kg
b - is
^foT^^
fonndeno[1,2.3-c,d]Pyrene. However, these changes are negligible in terms of risk
8. Table 7-25:
******* ** Ch'°rdaneS m a" °'35 per
°ra. RfDs are
The 1,2-dichloroethane target organs include the stomach and thymus.
The barium target organs include the kidney.
The new chromium oral RfD is 3E-3 mg/kg/day.
The inorganic mercury target organ is the immune system.
9. Table 7-26:
The new unit risk for chlordane is 1E-4 per ug/m3; the new RfC is 7E-4 mg/m3.
The 1.2-dichloroethane target organs include possible kidney effects.
The provisional aluminum RfC is 3.5E-3 mg/m3.
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The new beryllium RfC is 2E-5 mg/m3.
The new chromium RfC is 1E-4 mg/m3. •
10. Table 7-27: As noted elsewhere in the report, adjusted slope factors are not calculated for the
carcinogenic PAHs. The beryllium, chromium, and chlordane dermal numbers would change in
accordance with their new oral numbers.
11. The risk drivers for AREE 9 surface soil would be iron, mangenese, chromium, and vanadium,
which are aii similar to background levels (chromium tested with Mann-Whitney).
The risk drivers for AREE 11 surface soil would be chromium, vanadium, mercury, iron, and
chlordane, of which mercury and chlordane exceed background levels.
The risk drivers for AREE 13 surface soil would be aluminum, iron, chromium, and vanadium, of
which only chromium is similar to background levels (chromium tested with Mann-Whitney).
The risk drivers for AREE 16-1 surface soil would be arsenic, chromium, iron, manganese.
vanadium, and TCDD, of which arsenic, TCDD, and chromium exceed background levels.
The risk drivers for AREE 16-2 surface soil would be iron and vanadium, both similar to
background levels.
The risk drivers for AREE 17 surface soil would be iron, manganese, chromium, and vanadium,
which are all similar to background levels (chromium tested with Mann-Whitney).
The risk drivers for AREE 18 surface soil would be iron, manganese, and chromium, which are all
similar to background levels.
The risk drivers for AREE 19 surface soil would be iron, antimony, chromium, arsenic, and
vanadium, of which antimony and arsenic exceed background levels (chromium tested with Mann-
Whitney).
The risk drivers for AREE 21 surface soil would be iron, manganese, chromium, and vanadium, all
of which are similar to background levels (chromium tested with Mann-Whitney).
The risk drivers for AREE 24 surface soil would be iron, manganese, chromium, and vanadium, all
of which are similar to background levels (chromium tested with Mann-Whitney).
The risk drivers for AREE 27 surface soil would be chromium, vanadium, cadmium, and iron, of
which chromium and cadmium exceed background levels.
The risk drivers for AREE 29-2 surface soil would be iron and chromium, which are both similar to
background levels (chromium tested with Mann-Whitney).
The risk drivers for AREE 29-4 surface soil would be chromium, vanadium, beryllium, iron,
aluminum, and manganese, of which only aluminum exceeds background levels.
The risk drivers for groundwater are manganese and bis(2-ethylhexyl)phthalate (BEHP), of which
both are similar to background levels, although BEHP is not naturally occurring.
The risk drivers for western tributary sediment are arsenic, chromium, iron, manganese, and
vanadium, of which arsenic exceeds background levels.
The risk drivers for eastern tributary sediment are iron, chromium, manganese, and vanadium, all
of which are similar to background levels.
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12.
and
„„ nr „._.„ 3 . .. t u soil would be chromium, iron, manganese and vanadium
mrtney) ' baCkgr°Und (chromium- ^nadlum, and manganese testedI vT Mann!
SSa-SSSSSSHS-SS
However, all cancer risks wnnw remain hai«,« -ic /( —i _,. i_n . WUUIU Decrease.
^^
chduHin P- ,' a'°ng With Pages 7'44 and 7-»5: lnhala^n risks for the
dermal, and inhalation) for adults, 24-year exposure, would be 6E-4 the totaf HI Ic uW be°8 The
target organs and background, except for the following: consideration of
nnteSEn 13;JJ-e ir°4n HQ (in9estian + dermal) ^ 1.5; the vanadium HQ is 1 06 and these are
potentially addit,ve. Vanadium may not be attributable to background.
At AREE 16-1, the arsenic cancer risk is 5E-5; the TCDD cancer risk is 8E-5 f total IF &\- tho
'
At AREE 27. the cadmium HQ is 0.21; the chromium HQ is 1.22; these are potentially additive.
17. For Tables 7-108 through 7-137 and Table 7-149, along with pages 7-45 through 7-53-
ITa I'8 ad?d t0 ?H°me °f theSS AREES- lnhalation HQs c"uld ^ cacu ^ted or
inhalation nsks would mcrease due to body-weight consideration. Risks for chromiumTouTd
-------
increase, while risks for beryllium and chlordane would decrease. However, all cancer risks would
be less than 1E-4, and all His would be at or below 1 after consideration of target organs and
background, except for the following:
At AREE 11, the mercury HQ is 1.8; the chlordane HQ is 2.7. The chiordane cancer risk is 4E-5
The cancer risk on Table 7-149 should not be attributed to background.
At AREE 13, the aluminum HQ is 1.2; the iron HQ is greater than 10; the vanadium HQ is 2 6
Vanadium may not be attributable to background.
At AREE 16-1, the arsenic cancer risk is 5E-5; the TCDD cancer risk is 7E-5 (total 1E-4)- the
chromium HQ is 2.5. Chromium may not be attributable to background. The cancer risks on
Table 7-149 should not be marked "b."
At AREE 19, the antimony HQ is 1.5; the arsenic HQ is 1.4; these are potentially additive. The
His on Table 7-149 should not be marked "e."
At AREE 27, the cadmium HQ is 0.4; the chromium HQ is 2.2; these are potentially additive. The
His on Table 7-149 should not be marked "b."
At AREE 29-4, the aluminum HQ is 1.4; this was not attributed to background.
18. For Tables 7-138 through 7-141 and 7-150, along with pages 7-53 and 7-54: Beryllium risks would
decrease, while risks for chromium would increase. However, all cancer risks would be less than
1E-4, and all His would be at or below 1 after consideration of target organs and background.
19. For Tables 7-142, 7-143, and 7-151, along with pages 7-54 and 7-55: Risks for chromium would
increase, while risks for beryllium and chlordane would decrease. However, all cancer risks would
be less than 1E-4. and all His would be at or below 1 after consideration of target organs and
background, except for the following:
For western tributary sediment, the arsenic HQ is 2.5 and the arsenic cancer risk is 9E-5 (added
to a chlordane risk of 1E-5). The cancer risk should not be marked "c" on Table 7-151.
20. Beryllium should not be a cancer driver on Tables 7-144 through 7-151.
21. Table 7-152, .Section 7.1.4.3, Section 7.1.5.4: AREE 16-1 now has the highest cancer risk, and
AREE 29-4 has the highest HI. The risks on this table would change as previously noted.
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ATTACHMENT 2 ;
RESPONSE TO USEPA COMMENTS ON THE
AREE 14 INVESTIGATION SUMMARY REPORT
-------
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Response to Comments on the
Draft AREE 14 Investigation Summary Report, Vint Hill Farms Station
from USEPA Region HI
Comment: Section 4.1.4.4 includes a pre-excavation risk assessment. Hot spots were found and
removed in the miss zone; the remaining lead in the excavated area has an average
concentration of approximately 125 mg/kg. Because of the nature of the site activities it
is possible that other hot spots may be present. The contamination that was found at this
site was not homogeneous, and the original source was scattered rather than issuing
from an identifiable location (such as a tank, spill, transformer, etc.). Therefore, the
residential risks from lead cannot be truly known unless the skeet range is systematically
examined for lead, however, since the HUD guideline for lead in soil is 400 mg/kg a field
screening technique may be used instead of re-sampling to ensure that all the hot spots
have been removed from this AREE.
Response: It is important to note that the skeet range (AREE 14) at VHFS was only used on
weekends and thus would be expected to have limited contamination as compared to a
commercial skeet range. During the Site Inspection (SI), surface soil samples were
collected from randomly selected grid points. During this sampling, only limited
contamination was identified in the form of two hot spots. During the Supplemental
Remedial Investigation (SRI), these hot spots were'removed, and numerous confirmation
samples were collected which yielded an average lead concentration remaining at the
skeet range of 102 ppm (including all SI and SRI "left-in-place" samples), in addition on
December 10, 1998, USEPA, VDEQ, VHFS, USAGE, and ICF KE personnel conducted a
site walkthrough of AREE 14. During this site walk-through, no lead pellets or clay
pigeons were observed on the surface of the skeet range. In light of these observations,
the U.S. Army stands by its conclusion that the hazard previously posed by AREE 14 has
been removed and that no further sampling or action is required. It should be further
noted that USEPA agreed with this no further action determination in a subsequent
comment document (for the SRI) dated January 7, 1999, "... since the average
concentration for lead is 125 ppm and the HUD residential guidelines is set at 400 ppm ..."
DACA31-95-D-0083
TERC18-32
January 1999
Response to USEPA Comments
Draft AREE 14 Investigation Summary Report
Vint Hill Farms Station
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ATTACHMENT 4
PUBLIC NOTICE
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PURPOSE-
The United States Army
at Vint If ill Farms Station, Virginia
• Invites Public Comment
ON RECENTLY PROPOSED ENVIRONMENTAL ACTIONS
• FOR ViNT HILL FARMS STATION, AS A RESULT
OF THE BASE CLOSURE PROCESS
...» Please.Come.TaOur.*. '.'"_ •••
• PUBLIC MEETING •
• Thursday, April 15,1999 • 7:00 p.m.«
• Building 101 (Old Headquarters BIdg.), Conference Room >
.•.Vint Hill Farms Station. VA 20187 •
. %> V ' '. - ,-, -x- •"• _ *\-~
TO DISCUSS AND PRESENT. REMEDIAL ALTERNATIVES XKlO NO rtftTHE^ACTlbfV. PROPOSALS TOR • TH6?TSiTES
~ '- • '
DISCUSSED BELOW.
... /• . -. , v. • < . "-'^.i ••.--• •'•'•••?•
BACKGROUND • - - ' ' ...........
Vin« H« Farms Stalion is part ol Ihe U S. Army Communications • Electromcs Command (CECOM) and. while active. primaray
functioned as an Army installation engaged in communications intelligence. VHFS is located appronmatefy 40 miles southwest of
Washington. DC. Fauquier County. Virginia. The installation ^occupies approximately 701 acres o( land in Ihe town of Warranton,
Virginia. Approumalery ISO acres ol Ihe installation are improved grounds m the southern ponton ot the property used (or Industrial
operations, administration buildings, and residential housing. Appronmalely 94 acres on the eastern portion of the property ere
mature hardwood forest and the .majority of the remaning 457 unimproved and semi-improved acres «i the northern portion of the'
property are used for stationary and mobile antenna operation sites. The facility was designated for closure m March t993^under
1he Base Realignment and Closure (BRAC) Ad. ' . . ... •
• • •-.'•*' "SUMMARY , ' r~.' ' "''.'
Trie U.S. Army, In consultation with the U.S. Environmental Protection Agency (USEPA) Region 'ill and the Virginia
Department of Environmental Quality {VDEQ). invites public comment on proposed plans for numerous sites at VHFS.
Before selecting final remedies and making final no further action decisions, VHFS win consider all written and oral
comments received during the public comment period of April 1 through April JO.
f
The U.S. Army Is proposing remedlitlon for the landffl at AREE 1- Oumptfl'eM foj'the airfintfon
20 - incinerator Bunding. No further action Is proposed for groundwater undertyfng the MstataOon, a ponlon eXi
Run near AREE land AREE 2 Sewage Treatment Plant; and the three grassy drainage dttcnes. ' '
Additionally, the U.S. Army is proposing no further action at the following Areas Requiring Environmental'I
(AREEK: -
AREE J - Warehouse; •••-•.
AREE 5 - Environmental Photographic Interpretation
Center (EPIC) Building;
AREE 7 - Electrical Equipment Faculty;
AREE 10 - Former Photographic Wassewater Lagoon;
AREE 13 - Sludge Disposal Area;
AREE 14 - Skeet Range;
AREE1C-1 - Possible Firelighter Training PIC ' '-'
AREE1C-2 - Pantble Firefighter training Pit; ~
AREE1T - DumpKS;
AREE 1C - Crease Pit;
ARK 24
AREE2S
AREE2*
AREE 27
AREE2S-1
AREE21-2
AREE2S4
AREE2M
AREE 30
AREE 3 J
- Incinerator Septic T*nfclnd
• Transformer Storage An^ :
'Sugar Tree; '^ ''V : .,?7^^ •'••»t-
- Outdoor Wash rtae«s;.-v, .'«»
- AAFES Service Stattonr-':' '*•<..'
- Salvage Yard; . .• '-. 'M.
- Possible Stadee Disposal Area;
.-Possible Disposal Are.: .... .
—^Disposal Area;-- •'• • • -''
- Motor Pool: and '
- Household Debrts me.
The U.S. Army will be accepting comments during a JO-OAT PUBLIC COMMENT PERIOD, which
beams Thursday. AprB 1 « ends Friday. April 30.1»OT.
WRITTEN COMMENTS MAY BE SUBMITTED TO THE FOLLOWING ADDRESS:
Kevin Bell, Public Affairs Officer
Vint Hill Farms Station
Building 2500. Helms Road ' '
Warrenton.VA 201t7 . -•'•
PROPOSAL
VHFS evaluated four remeauXanernalives to address soil contamnauon at AREE t: .
ALTERNATIVE 1:
ALTERNAHVE 3:'
No Action;
Clay Cap;
ALTERNATIVE 2: Eicavatlon of Lamrnu;
ALTERNATIVE4:••LinerCap. - ••
Based on available information. VHFS prefers Alternative 4, which consists of constructing a liner cap over the AREE 1 laodfS and
implementing land use reslnetions. This- remedial alternative offers adequate protection of human heath and the environment,-
providing both short- and long-term1 effectiveness by: 1} removing the "potential for direct contact with the contaminated soir and 2)
reducing the mobilization of contaminants-m so4 to other media. Due to the cuiiiuteaily that would be required for a treatment
syslem fo effectively treat the wide variety ol contaminants present, it was not practical to consider active treatment in terms of cost-
effectiveness and the ability to implement. Capping of the landfill would be done in accordance with applicable Federal and
Commonwealth of Virginia regulations. ' " * :•' '.4.'." '"._
-''^•"' *••• - '.-"." '"•"'-t* T~*
VHFS evaluated two remedial alternatives to address the incinerator building at AREE 20: x ..--.... • I. i . '.^.-. "v.^^*
ALTERNATIVE!: NoAcllon; ALTERNATIVES Ash and OtTRernaval: ."?7-{< 1 "T^.
Based on available information. VHFS prefers Alternative 2. which consists of the removal of ash and od from Ihe incinerator sho-
rts off-site disposal at a permitted facility This remedial alternative is a permanent solution that offers king MjliiVcrTecUVeness.-'sinei^
the contanunated matenats are removed and transported off site for proper disposat. The removal and disposal of ash amfoil'woutd
be done in accordance with applicable Federal and Commonwealth of Virginia-regulations. '* ' ' *" 4f ~"?
In addition. VHFS prefers no furtnw »ction for AREEs 3. S. 7. li. ;3. 14. -.G-t. !S-2. 17. 58. 23. 24. is. 26. 27. J9-1. 2*-2. 29-3.
29-4. 30 and 33: Ihe qroundwaler underlying the "islallation. Ihe South Run at AREEs 1 and 2. and three grassy drainage ditches.
because these areas pose no unacceptable human health or ecological risks
FOK MORE INFORMATION
You can review the Propose*) Plan and related technical documents at thebiformation Repository at Ihe foHowing location:
Fauquier County Library . ,
Warrenton Branch - Reference Section
11 Winchester Street ' ~ '..
Wanenton. VA"2018«
PHOTO- (540) 347.8750
Hoiirs M-V/ '0 .1 m - 9 p m . Th -S.i|- 9am -5pm, and Sun- 1 p m - 5 p m
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ATTACHMENT 5
PUBLIC MEETING ROSTER
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Vint Hill Farms Station
Sign-In Sheet
Thursday ,ApriM 5,1999
Public Meeting 7:00 P.M.
Recently Proposed Environmental Actions
for Vint Hill Farms Station, as a Result of
the Base Closure Process
If you wish to speak, please sign in on the lines below. Your name will be called in the order that it appears. Thank you.
£
l£
(M
S-
Continued on Back
K
en
i
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Vint Hilf Farms Station
Recently Proposed Environmental Actions
for Vint Hill Farms Station, as a Result of
the Base Closure Process
Sign-In Sheet
Thursday, ApriH5,1999
Public Meeting 7:00 P.M.
If you wish to speak, please sign in on .he lines below. Your name will be called in the order that it appears. Thank you.
Continued on Back
*
CM
o
ro
§
(M
•>H
U)
o
in
G)
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ATTACHMENT 6
WRITTEN COMMENTS FROM REGULATORS AND U.S. ARMY RESPONSES
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•After mailing recent Proposed Plans to the public, the U.S. Army received comments on the Proposed
Plans from the U.S. Environmental Protection Agency (USEPA) and the Virginia Department of tf»
fS2^7CJn^^SSrtSF?>5ito PUb{iC'S ^ °'"6™posed ^onmenta,
USEPA and VDEQ to the public. Please note that the comments tha'tlr^ag^ed'to £>y tte^S.^rmy™l
be incorporated into the Decision Documents for the affected sites.
Response to Comments on the Proposed Plans for
Vint Hill Farms Station from USEPA Region III
AREES 13.14. 16-1. 27 3nd
Comment:
Response:
Delete "contaminated soil" so the sentence reads "alternative to address selected Areas
Requiring ...
The U.S. Army agrees with this suggested wording change.
Comment:
Response:
Comment:
Response:
If the report is still being reviewed, how can we rely on a report conclusion about risk?
The SRI was conducted to fill data gaps identified in the RIs (e.g., the extent of the AREE
1 landfill). The SRI does not-include risk assessment. All risk conclusions were made
based on the RIs.
(1982) By whom? Any regulator involvement? (1992) By regulator or Army decision to
stop?
Based on available knowledge, AREE 13 was not regulated; therefore, decisions to
spread sludge and later to remove the sludge and close the disposal area were
presumably made by the U.S. Army.
Comment: As part of Rl?
Response: Samples at AREE 13 were collected during the SI and the Rl.
Comment:
Response:
Nothing in the hit zone?
The lead concentrations in the Hit Zone did not exceed the USEPA screening level for
lead in residential soil of 400 ppm.
Comment: Why "possible" in heading but not text?
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Response:
Comment:
Response:
locations of the Firefighter Training Pit.
^'Juuoh-tas^plTraQ
2 represent
Discharges or discharged?
Discharges.
_
Comment: Mentions arsenic and lead but what about chromiurr^see P7ge
Response:
I ------ — • »»witw«,lll IUI lill^ClClS IO Ul(
Co
Comment:
Response:
Should stored be disposed?
Yes.
Comment:
Response:
Isn't iron naturally occurring? If so, why wasn't it discounted?
Comment: Current and future land-use conditions... What are these?
Response: See response to Comment 10.
Comment: "Soil in those... was excavated." Removed and disposed off site?
Response: Yes, the excavated soil was removed and disposed off site.
-------
Comment: Current and future land-use conditions ... What are these?
Response: See response to Comment 10.
Comment: "contaminants"... Are you referring to arsenic, TCDD?
Response: Yes.
Comment:
Response:
Current or future land-use conditions ... What are these?
Chromium not mentioned on page 6. What about-arsenic?
See response to Comment 10.
See response to Comment 8 regarding chromium. Arsenic was not a risk driver at AREE
Comment: "Therefore, the HI of 1.3 ..." instead of "therefore a HI of 1.3 ..."
Response: The U.S. Army agrees with this suggested wording change.
[Cprrimei
Comment:
Start the sentence from "lead contamination" and insert "explained in the AREE 14
discussion" after IEUBK Model.
Response: The U.S. Army agrees with this suggested wording change.
Comment: Current or future land-use conditions ... What are these?
Response: See response to Comment 10.
Comment: Are you referring to aluminum, benzo(a)pyrene, beryllium, arsenic, and iron?
Response: The text is referring to any contaminant identified as a chemical of potential concern that
was not determined to be naturally-occurring. Benzo(a)pyrene and aluminum are the only
two contaminants that meet these criteria.
AREES 3. 5. 7. 10. 16-2. 17. 18. 20. 24. 25. 2fi. 29.1. 29-2. 29-3. 30. and 33. anri
Sroundwater. South Run at
2. and Qth«r Slf» np,|nmr
Comment: Is this a No Further Action or No Action Proposal?
Response: No Action.
-------
, _ . •••••••MiB^^^M^^^^v^H^^^^^^^^^^^^^^^^B^^^^^,^^^^^!
Comment: Delete 'contamination at" so the sentence reads "alternative to address selected Areas
Requiring..."
Response: The U.S. Army agrees with this suggested wording change.
PseslrioftjnacceptaDle
!ltEO^
Comment: If the report is still being reviewed, how can we rely on a report conclusion about risk?
Response: See response to Comment 2.
Comment: I'm concerned because we can't necessarily say that property is okay for unrestricted
future use. In which case, we'll need institutional controls, a remedy. See AREE-specific
comments below.
Response: See responses to AREE-specific comments below. Based on these responses
unrestricted future use is okay.
Comment: "The Warehouse also may have been ..." instead of "The Warehouse may have been ..."
Response: The U.S. Army agrees with this suggested wording change.
Comment: What about residential risk? Consider a scenario where the property is reused as
residential and trees are planted, with the tree pits dug below 2 ft bgs. Subsurface soil
could then sit at the surface and be consumed by a child.
Response: The U.S. Army's understanding of USEPA's position is that soil below 2 ft bgs only needs
to satisfy target risk levels for excavation workers and not residents since residents would
be unlikely to be exposed to subsurface soils. In addition, 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 mixing of subsurface soils with surface soil, clean topsoil, and other soil
amendments. Therefore, it would not be appropriate to evaluate risks to residents using
available subsurface soil data.
Comment: AREE 7 will need to be closed under RCRA by VDEQ before FOST/transfer.
Response: The U.S: Army understands the requirement for clean closure of AREE 7 by VDEQ before
a final No Action decision can be made. A closure report has been submitted to VDEQ.
. and approval is pending. i
Comment: How was the overflow from the lagoon discharged? Via earthen trench? Pipe?
Response: The lagoon and WSRT were connected naturally. The lagoon overflowed directly into
WSRT.
-------
Comment:
Response:
What about sampling of the surface soil around the lagoon?
The lagoon was dredged and backfilled such that any residual contamination would be
presentat tne base of *>e former fagoon (i.e., 4 - 4.5 ft bgs) and not at the soil surface.
Comment:
Response:
Why is it the "Possible" Firefighter Training Pit?
See response to Comment 6.
Comment:
Response:
AREE 16-1 only discusses surface soils. Was the sampling different for the two AREEs?
Soil samples at AREE 16-1 could not be collected at depths below 2 ft bgs because
bedrock was encountered.
Comment:
Response:
The AREE 16-1 text doesn't give this range.
A range of maximum background arsenic concentrations is given for AREE 16-2 and not
A oil 16~1 because both surface soil and subsurface soil samples were collected at
AREE 16-2, while only surface soil samples were collected at AREE 16-1 (see response
to Comment 30).
Comment:
Response:
Explain how analytical results indicate that soils have not been adversely impacted? Is it
because only arsenic was found and not dioxins/furans? Then where does the arsenic
come from?
Soils have not been impacted because arsenic was the only contaminant that exceeded
screening levels at AREE 16-2, and the arsenic concentrations at AREE 16-2 were
determined to be statistically within background levels.
Comment: How deep is the dump? Is it unlined?
Response: Based on observations made during test pit excavation, the dump extends to depths up to
7 ft in some areas. The dump is unlined.
Comment:
Response:
Are there any elevated lead levels?
No.
Comment: Is groundwater contamination a concern?
-------
Response:
No.
Comment:
Response:
Comment:
Response
Were hazardous materials stored in the "Salvage Yard"?
To the U.S. Army's best knowledge, no.
What about the sludge piles themselves?
Based on review of aerial photography, there was a possibility that AREE 29-2 may have
been used as a sludge disposal area. However, during sampling, there was no sludge
prsssnt.
Comment: Were hazardous materials stored at the "Possible Disposal Area"?
Response: To the U.S. Army's best knowledge, no. '
I q°™g:Mg9^.3gg^^^
Comment: "a petroleum odor was detected" instead of "a petroleum odor was observed".
Response: The U.S. Army agrees with this suggested wording change.
"No contamination above screening levels..." What were trie screening levels?
USEPA Region III risk-based concentrations (RBCs), the USEPA screening level for lead
in residential soil, Virginia's TPH soil action level, and maximum background
concentrations.
Comment:
Response:
1
Comment:
Response:
Industrial soil RBCs were used as the screening levels. Why not residential (subsurface)
RBCs? '
Industrial soil RBCs were used to screen soil results at AREE 33 because the soil sample
was collected from greater than 2 ft bgs (i.e.. excavation workers are the most likely
human receptor). Also, see response to Comment 25.
Comment:
Response:
a
"...composition of the aquifer..." Is there only one aquifer?
The groundwater "aquifer" of concern at VHFS consists of groundwater in the overburden
and in fractured bedrock which are interconnected (i.e., there is no defined confining unit).
Therefore, it is evaluated as a single aquifer.
Comment:
"Metals. PAHs. and pesticides were detected at concentrations above screening levels.
What are the screening levels?
-------
Response: The more stringent of the Effects Range - Lows and the No Effects Levels or Lowest
Effects Levels for sediment which are protective of benthic organisms, and maximum
background concentrations.
Comment:
Response:
"In addition, the HHRA evaluated potential risks to hypothetical future adult residents who
could be exposed contaminants in groundwater and surface soil and to hypothetical future
child residents who could be exposed to contaminants in groundwater, surface soil
surface water, and sediment." What about subsurface soil?
For subsurface soil, the HHRA evaluated risks to excavation workers, the human receptor
most likely to be exposed to subsurface soil. Also, see response to Comment 25.
Comment: Current and future land-use conditions ... What are these? Maybe say "current
industrial/commercial use or potential future residential use conditions", or unrestricted
future land use conditions.
Response: See response to Comment 10.
Comment:
Response:
With regard to the.excavation workers, there is no mention of subsurface soil exceedance
of industrial RBCs. What about residential RBCs?
Although industrial soil RBCs were exceeded by contaminants in subsurface soil as
indicated on page 4, the concentrations of contaminants yielded risks lower than those for
residents exposed to surface soil; therefore, only the risks for residents are presented.
Also, see response to Comment 25.
Comment: Is there any reason to collect surface soil samples?
Response: Only subsurface soil samples were collected because the industrial sewerline is buried at
least 5 ft bgs.
Comment: Risks to excavation workers are presented. What about residential exposure risks?
Response: See response to Comment 25.
Comment: Current and future land-use conditions ... What are these?
Response: See response to Comment 10.
Comment: Why were surface soil samples not collected?
Response: See response to Comment 28.
-------
Comment:
"... so the HHRA only evaluated risks to future excavation workers."...Then can we say
that property is okay for unrestricted future use?
Response: See response to Comment 25.
Comment: "No ERA was conducted at AREE 10 because all samples were collected at depths of
greater than 6 inches." Depths from 0 inches to 2 feet are defined as "surface soil".
Internal inconsistency created.
Response: The USEPA protocols for HHRAs and ERAs differ with respect to the definition of "surface
soils" to which receptors are exposed. ERAs only use data for surface soil samples
collected from the 0-6 inch depth interval, while HHRAs use data for surface soil samples
collected from the 0-2 ft depth interval. The U.S. Army followed USEPA's protocols.
Comment: Why is it the "Possible" Firefighter Training Pit?
Response: See response to Comment 6.
Comment: Current or potential future land-use conditions ... What are these?
Response: See response to Comment 10.
Comment: What about residential risks to subsurface soil?
Response: See response to Comment 25.
Comment: Current and future land-use conditions ... What are these?
f
Response: See response to Comment 10.
Comment: What about residential'risks to subsurface soil?
Response: See response to Comment 25.
Comment: Current and potential future land-use conditions ... What are these?
Response: See response to Comment 10.
Comment: Did the HHRA consider residential exposure to subsurface soil?
Response: See response to Comment 25.
-------
Comment: Current and future land uses ... What are these?
Response: See response to Comment 10.
Comment:
Response:
(Comment!*
^•^*2:±j^^^^^^^^*^^
Comment:
Response:
Current and future land-use conditions ... What are these?
"... risk to workers, trespassers, and ..." should be "... risks to workers, trespassers, and
See response to Comment 10.
The U.S. Army agrees with this suggested wording change.
"...for child residents exposed to contaminants in surface soil
contaminants? PCBs? Metals?
What are these
The text is referring to .any contaminant identified as a chemical of potential concern that
was not determined to be naturally-occurring.' Aluminum is the only contaminant that-
meet these criteria. PCBs were not detected in surface soil at AREE 24
Comment:
Response:
Are toxicologists satisfied that this area is okay for residential use?
Based on discussions with USEPA, it is the U.S. Army's understanding that this area is
okay for residential use based on the BRA findings.
Comment: Current and future land uses ... What are these?
Response: See response to Comment 10.
Comment:
Response:
I j^. a!.Si«sv5*4t«'f"!'55i
|CommentJ
Comment:
Response:
Current and potential future land-use conditions ... What are these?
See response to Comment 10.
"...for child residents exposed to contaminants in surface soil
contaminants?
.." What are these
The text is referring to any contaminant identified as a chemical of potential concern that
was not determined to be naturally-occurring. Aluminum is the only contaminant that
meet these criteria.
Comment: What about the materials which were piled there?
Response: See response to Comment 37.
-------
Comment:
Response:
Current and future land-use conditions ... What are these?
See response to Comment 10.
Comment:
Response:
"... for child residents exposec to contaminants in surface soil ..." What are these
contaminants? Page 9 doesn't mention surface soil, just subsurface soil.
The text is referring to any contaminant identified as a chemical of potential concern that
was not determined to be naturally-occurring. For AREE 29-3 surface soil no
contaminants meet these criteria. The risks presented for -child residents exposed to
contaminants in surface soil by dermal absorption is actually the risk associated with
exposure to background metals (i.e., aluminum, arsenic, beryllium, iron, and manganese)
which were only discounted if risks were found to exceed USEPA's target risk criteria.
Page 9 does not mention contamination in surface soil because none of the detected
compounds exceeded screening levels (i.e., residential soil RBCs and maximum
background concentrations).
Comment:
»^^^^^^^^^^^«™«^^^^^^^^^^*
"An ERA was not conducted because all soil samples were collected at depths greater
than 6 inches." Are depths greater than 6 inches defined as surface or subsurface soil?
Response: See response to Comment 52.
Comment: "... human health risks were only evaluated for future excavation workers." Why?
Response: See response to Comment 25.
Comment:
Response:
"All analytes were detected below their screening levels ..." What are the screening
tevels? b
LJSEPA Region III industrial soil RBCs. the USEPA screening level for lead in residential
soil, and maximum background concentrations.
Comment:
Response:
Can't determine that AREE 30 is safe for unrestricted future use based only on human
health risks for future excavation workers.
See response to Comment 25. Based on this response and the findings of the BRA, it is
the U.S. Army's understanding that unrestricted use of AREE 30 is okay.
Comment: Why were only subsurface soil samples collected at AREE 33?
Response: The purpose of the RI at AREE 33 was to determine if the household debris present had
impacted the native soils which were encountered at greater than 2 ft bgs.
-------
*-ts= ;^t.;p-.-i>
Comment: Why is there no information regarding residential reuse risks?
Response: See response to Comment 25.
Comment:
Response:
—^^—^«>^VBB^^^^^M^^^^*^H«MM|
"naturally- occurring" should be "naturally-occurring"
The U.S. Army agrees with this suggested wording change.
Comment:
Response:
>^—w^^^MBHBHB^^H^^HM^H^BBHI^Ka^^^^^^^^^^^^^
Excluding bis(2-ethylhexyl)phthalate, what are the risk and HI? What is the contaminant
with the next highest risk?
Excluding bis(2-ethylhexyl)phthalate along with naturally-occurring metals that were
statistically determined to be within background levels, the highest estimated upper-bound
excess lifetime cancer risk (9x10^) is for adult residents exposed to contaminants in site-
wide groundwater by ingestion, and the highest noncarcinogenic risk (Hl=0.5) is for child
residents exposed to contaminants in site-wide groundwater by ingestion. The site-related
contaminants with the greatest impact on cancer risks and noncarcinogenic hazards are
beryllium and barium, respectively.
Comment: Current or future land-use conditions ... What are these?
Response: See response to Comment 10.
Comment:
Response:
"Although the HI associated with incidental ingestion exposures to sediment in South Run
at AREEs 1 and 2 by child residents exceeded 1, the exceedance was driven by metals
believed to be naturally occurring." ... Why weren't the metals discounted before running
the calculations?
Statistical background comparisons could not be conducted for sediment .sample results
because of the limited number of available background samples. Therefore, all metal
results were included in the calculations.
Comment:
Response:
Based on the potential for adverse effects to benthic organisms in the tributaries to South
Run at AREEs 1 and 2 identified in the ERA, shouldn't an action alternative be evaluated?
The ERA estimated the potential for adverse effects to benthic organisms based on the
assumption that a viable habitat for benthic organisms existed. However, the habitat for
benthic organisms in the tributaries to South Run at AREEs 1 and 2 is limited and,
therefore, the adverse effects are over-estimated by the ERA and are actually limited. No
action is warranted based on the existing conditions.
Comment: Current or potential future land-use conditions ... What are these?
Response: See response to Comment 10.
11
-------
Comment:
Response:
Comment-
Response:
Delete "contaminated materials at".
The U.S. Army agrees with this suggested wording change.
"major characteristic" should be replaced with "major component".
The U.S. Army agrees with this suggested wording change.
___
Comment: Should read "... the structure . and the Army shut down incinerator permanently"^
Response: The U.S. Army agrees with this suggested wording change.
Comment: Replace "... (i.e., boxes ..." with "... (e.g., boxes ..."
Response: The U.S. Army agrees with this suggested wording change.
5ti5!
Comment:
Response:
What if it isn't?
Comment: Delete "further" in "no further action".
Response: The U.S. Army agrees with this suggested worc'ng change.
Comment: How big is the incinerator?
Response: Approximately 45 ft long.
Comment:
Response:
Under which regulatory program?
/n free liquids from waste materia's ls rec?uired
ion (DOT) regulations and disposal facility permits.
Department of
Comment: Under which regulatory program?
12
-------
Response:
sS
Comment:
Response:
Solid waste landfills in Virginia are not permitted to accept elevated dioxin/furan
concentrations. Although the waste will still be managed under the Solid Waste
Management Regulations, it will require special management because it will have to be
disposed in a landfill that is permitted to accept elevated dioxin/furan concentrations
Replace "e.g." with "i.e."
The U.S. Army agrees with this suggested wording change.
Comment:
Response:
^j^_tr^^^^pjq^r^Jn
There doesn't appear to be a risk driver; no CERCLA trigger for an action. Write this as a
No Action Proposed Plan for this AREE.
Per USEPA's comment, a No Action Decision Document will be written for AREE 20 The
r!=o^rTy.Wi" rem°ve and dispose of the ash and oil as a BRAC action rather than a
CERCLA-dnven action.
^"^•^•••••^•••'•••i^^«**i™B«|*W««p«ap»BBBB-BB|
This doesn't appear to be warranted under CERCLA. As a CERCLA ROD no action
would seem to be appropriate. The ash and oil removal seems like a separate BRAC
Comment:
Response: See response to Comment 92.
AREE1
Comment:
Response:
Delete "contaminated soil".
-The U.S. Army agrees with this suggested wording change.
Comment:
Response:
Cpngjjeg
Comment:
Response:
Replace "characteristics" with "components".
The U.S. Army agrees with this suggested wording change.
dBJMddyiHll^^
Delete".,. and is currently undergoing regulatory review."
The U.S. Army agrees with this suggested wording change.
Comment: Under all scenarios?
Response: Yes, under all scenarios evaluated.
Comment: Spell out Rl.
Response: This is not necessary since Rl was spelled out on page 2.
1
13
-------
Comment:
Response:
~^^M>^MM^H^^M^^^^^^«^^^^M^^^^^^^ES35w^^S^5E5^^5^^^5^^^^^^^^^HHHHHHMHMH
What are the risk numbers for workers, trespassers, and excavation workers?
The risk numbers for workers, trespassers, and excavation workers are too numerous to
mdrndualy in, the Proposed Plan. However, discounting naturally-occurnng
noni Were Ste?te;cal|y determined to be within background levels, the cancer risks
noncarc.nogen.c hazards for workers, trespassers, and excavation workers by
sntal ingest,on, derma, absorption, and inhalation are below USEPA's target risks of
I and Hl=1. respectively.
Comment: -2.3,7.8-TCDF-... spell out TCDF.
Response: Tetrachlorodibenzofuran.
Comment: Delete "draft".
The U.S. Army agrees with this suggested wording change.
Insert "of after construction
Response; The U.S. Army agrees with this suggested wording change.
Comment: Have the type/costs and O&M been considered for land use restrictions?
Response:
The type of land use restrictions considered are deed restrictions. These deed restrictions
would be imposed after the cap is constructed and would limit uses of the property to
activrt.es that would not impact the integrity of the cap. For example, activities requiring
excavation of the property would be prohibited. Further definition of the land use
restnctoons will be made once a finai remedial alternative is selected, and will be included
in the Decision Document for AREE 1.
The capital costs for implementing land use restrictions have been included as a line item
in the FS cost estimate. The O&M cost contingency included in the FS cost estimate
would cover any long-term O&M requirements for the land use restrictions
Comment:
Response:
— .. _ ..^^
Have these been thought out? Will the county accept zoning ordinances and pending
restrictions? What about monitoring of institutional controls? What are the permitting
restrictions? What will happen during the window of the landfill cap installation and the
feme of transfer?
Further definition of the land use restrictions will be made once a final remedial alternative
is selected, and will be included in the Decision Document for AREE 1 The Decision
Document text will address the issues raised by USEPA (i.e.. county acceptance of
zoning ordinances, permitting restrictions, and monitoring of institutional controls) as
appropriate.
The landfill will not be transferred until cap construction is complete. Since the U.S. Army
will maintain control over the use of the landfill property until such time as the property is
transferred, land use restrictions will not be required during this time period. Since the
risks associated with current industrial/commercial use were found to be acceptable,
-------
access restrictions will not be required prior to cap construction. Access restrictions (e.g.,
safety fencing), however, will be maintained during cap construction to protect the public
from construction hazards.
Comment:
Have these been thought out? Will the county accept zoning ordinances and permitting
restrictions? What about monitoring of institutional controls? What are the permitting
restrictions? What will happen during the window of the landfill cap installation and the
time of transfer?
Response: See response to Comment 104.
Comment: Replace "because it removes" with "because it would remove".
Response: The U.S. Army agrees with this suggested wording change.
Comment: Replace "will be implemented" with "would be implemented".
Response: The U.S. Army agrees with this suggested wording change.
Comment: DOT and OSHA regulations are not ARARs.
Response: The U.S. Army acknowledges this comment.
Comment: Hasn't this been evaluated/determined? What about landfill design standards in the waste
regulations?
Response: Based on available data, the landfill contains non-hazardous waste and, therefore, would
be governed by the Solid Waste Management Regulations. The landfill capping
alternatives considered were identified based on this conclusion. However, if Alternative 2
were to be selected, waste characterization samples would be required by the disposal
facility. Although not anticipated, if any portion of the excavated waste was found to be
hazardous, Hazardous Waste Management Regulations would apply to the affected
waste.
Comment: Change "form" to "from".
Response: The U.S. Army agrees with this suggested wording change.
Comment: No basis given for this since no details regarding the institutional controls have been
provided. What are the reuse plans in and around this area?
Response: See response to Comment 104. The reuse plans in and around this area have not yet
been finalized.
15
-------
Comment: No basis to evaluate implementability of institutional controls.
Response: See response to Comment 104.
Comment: What abrut the cost of institutional control implementation and future monitonng?'
,. Response: See response to Comment 103.
Comment: What about institutional controls?
Response: The preferred alternative will include land use restrictions (a.k.e.. institutional controls).
Response to Comments on the Proposed Plans for
Vint Hill Farms Station from VDEQ
AREES 3. $. 7. 10. 16-2. 17. 18. 20. ?4. 25. 26 «uf. 29-2. 29-3 an a»H 33
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ATTACHMENT 3
PROPOSED PLAN
-------
-------
Proposed Plan
AREEs 13,14,16-1, 27 and 29-4
Vint Hill Farms Station, Virginia
March 1999
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 U S -Army's preferred
alternative is no further action at these AREEs.
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 five 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 the action presented in the Proposed Plan. The public comment period
begins on April 1, 1999, and closes on April 30, 1999. Please send your comments, postmarked no later
than April 30. 1999, to:
Kevin Bell, Public Affairs Officer
Building 2500, Helms Road
Vint Hills Farm Station
Warrenton, VA 22187
In addition, you are invited to a public meeting regarding the investigation of the selected AREEs at VHFS.
Representatives from the U.S. Army will report on the status of these AREEs and the U.S. Army's preferred
alternative. The meeting is scheduled for
Thursday, April 15, 1999 at 7:00 pm
Building 101 - Former Headquarters Conference Room
Vint Hill Farms Station, Warrenton, VA
Special provisions will be made for the handicapped and hearing impaired.
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.
-------
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 Environmental Response, Compensation, and Liability Act
(CERCLA), as amended, commonly known as the "Superfund Program', and the National Environmental
Policy Act of 1969 (NEPA). This Proposed Plan focuses on AREEs 13, 14. 16-1, 27 and 29-4. Other areas
of VHFS that the U.S. Army plans to remediate are addressed by separate Proposed Plans.
SITE BACKGROUND
VHFS is part of the U.S. Army Communications - Electronics Command (CECOM) anc 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.
The facility was designated for closure in March, 1993, under the Base Realignment and Closure (E3RAC)
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. 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 were investigated as part of the Phase I and Phase II reuse area Remedial
Investigations (RIs), and the Supplemental Remedial Investigation (SRI) conducted by ICF Kaiser Engineers,
Inc. (ICF KE). The purposes of these reports 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 Reports for the Phase I and
Phase II reuse areas were completed in April, 1998. and January, 1999, respectively. The draft SRI Report
was completed in November, 1998, and is currently undergoing regulatory review.
Five AREEs were identified in the RIs and SRI as having soil contamination which poses no unacceptable
human health risks and/or significant adverse ecological effects:
• AREE 13 - Sludge Disposal Area;
• AREE 14 - Skeet Range;
• AREE 16-1 - Possible Firefighter Training Pit;
• AREE 27 - AAFES Service Station; and
• AREE 29-4 - Disposal Area.
The locations of these AREEs are shown on Figure 2.
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ANNE
ARUNDEL
MONTGOMERY
MARYLAND
PRINCE GEORGES
\
VINT HILL
FARMS STATION
*\
PRINCE WILLIAM
GENERAL LOCATION
OFVHFS
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AREEs LOCATIONS:
IJ SUItKE OISPOSAI ARM
H sxrrt RWICE
16-1.... POSSI6U nROKMItR IFWHING PH
14 2' WK SCRV1CC SIAIKJN
29-< OlSPOyi AflO
N
PHASE I REUSE AREA
0 400 BOO
J i iL-
SCA1I IM IUI
1600
PHASE U REUSE AREA
FIGURE 2
GENERAL LOCATIONS
OFAREEsATVHFS
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RESULTS OF THE REMEDIAL INVESTIGATION
The Rls for these five AREEs were conducted to evaluate the nature and extent of contamination
associated with past s,te activities. Environmental samples collected and analyzed during tte R^were
used ,n conjunction with the results from the SI to assess the condition of e?ch of the AREEs The
environmental media investigated included surface soil (0 to 2 feet below ground surface fbasn
subsurface soil (greater than 2 feet bgs), surface water, sediment, and groundwl er Analvfcal resufs
were compared to background concentrations and regu.atory screening levSs To deten^?ne ff
T™ I tlm^hadtbfiee; adV€f,ely JmpaCted by Site aCtivitie*- A brief ** of each oMhe five
sinificant findings of the Rls and SI are presented in the following paragraphs A detailed
ana'ytiCal rSSUltS C3n be found in the final Phase I Reuse
in the lnformation ****** at
AREE 13 - Sludge Disposal Area
tS[CTpe> DanPd0thalAfnramriTpSed *T"9 5V9808 l° dlSP°Se °f S'UdgeS from the Sewa9* treatment
t (STP) and the former STP, and sand filter sludge and sandblasting waste from the Electric
SnSLT8011^ 'nH9?2' Ihe'slud9es ™* Analyzed for total metals and'were Lermined to bea'
iqS H sufficient|y|OW for !and sPrea*ng- The sludge pile was 75 feet in diameter and 3 feet high
1992. he area was closed, with twenty thousand cubic feet of sludge being excavated mixed with
digester* and transported to the
onn , 8r°" SamplSS Were C0llected at locations witnin'the disP^al area. Iron (75,200 to
230,000 parts per million [ppm]) was the only analyte detected above its residential soil RBC (23 000 ppm)
and maximum background concentration (70,800 ppm).
AREE 14 - Skeet Range
AREE 14 was used on weekends as a skeet range between 1961 and 1994. The spent ammunition
consisting of lead and steel shotgun pellets, was spread over the range and remains uncovered The
9 an IS oriented eastward in an 800-foot radius and is separated into the Hit and Miss
Surface soil samples collected from two locations in the Miss Zone contained lead concentrations (940
ppm, and 414-650 ppm) that exceeded the USEPA screening level for lead in residential soil of 400 ppm.
AREE 16-1- Possible Firefighter Training Pit
The Firefighter Training Pit was used monthly by the VHFS Fire Department for training in the mid-1970s
The unlined pit was approximately 50 feet in diameter and 3 feet deep. During training activities the pit
was partially filled with petroleum and natural gas odorant and then ignited. Solvents and other
combustible matenals may have also been used in the pit. In the mid-1980s, the pit was filled with VS-inch
gravel.
Total petroleum hydrocarbon (TPH) field screening of the soil at AREE 16-1 was conducted to delineate
the area of contamination and to determine where soil samples should be collected for laboratory analysis
Surface soil samples were collected based on positive TPH results from the field screening. Arsenic (up
to 21.6 ppm) exceeded its residential soil RBC (0.43 ppm) as well as its maximum background
concentration (4.89 ppm) in the surface soil samples collected at AREE 16-1. A number of dioxins/furans
indicative of combustion operations, were detected in the surface soil samples. 2.3,7,8-TCDD (2 74E-04
ppm) was the only dioxin/furan to exceed its residential soil RBC (4. 3E-06 ppm).
AREE 27 - AAFES Service Station
The AAFES Service Station (Building 238) was constructed in 1969 to provide fuel and service for VHFS
personnel vehicles. The service station had underground storage tanks (USTs) for three grades of
-------
gasoline, a pump area, and a service station area with two lifts. Drains in the pump island area lead to a
grit chamber, which discharges to a field north of the facility. In addition, a fenced storage area was
located in the rear of the facility for tires, batteries, and drums. Several gasoline, oil, and other'spills were
reported in this area. In April, 1993, pressure testing of the regular unleaded gasoline pipeline confirmed a
suspected teak. A 0.5-inch hole was found in the pipeline within the pump area. The corroded section of
pipe was replaced, and the soils around the area where the leak occurred were excavated and then
backfilled. The system was re-tested to ensure no other leaks existed, and the pump was re-opened.
During the summer and fall of 1993, field investigations confirmed soil and groundwater contamination due
to the release of gasoline from one or more leaking USTs and associated distribution piping. The USTs
were closed in June, 1994. and removed in November, 1994. Operations at the AAFES Service Station
1 were discontinued in the fall of 1994. Contaminated soil removal and groundwater remediation activities
at the AAFES Service Station have been initiated and are being handled separately from the rest of AREE
27. .
Surface and subsurface soil samples were collected from areas of potential contamination: downgradient
from the discharge point of the grit chamber, at the service bay spit: run-off area; and ir. the tire storage
area. Arsenic (up to 12.2 ppm) was found to exceed its residential soil RBC (0.43 ppm) and maximum
background concentrations (4.89 ppm surface soil and 5.4 ppm subsurface soil) in most of the surface
and subsurface soil samples. Lead was detected in a surface soil sample at the discharge point of the grit
chamber, at a concentration of 1,200 ppm, which is three times the USEPA screening level of 400 pprn for
lead in residential soils. The maximum TPH concentration detected was 2,310 ppm, which is significantly
higher than the State's TPH soil action level of 100 ppm for UST sites, in the surface soil sample collected
at the discharge point of the grit chamber. TPH (737 ppm) was also detected above the State's TPH soil
action level for UST sites in the surface soil at the service bay spill run-off area immediately off the parking
pad. However, TPH did not exceed the State's TPH soil action level for UST sites downhill frofn the grit
chamber, further along the spill runoff pathway, or in subsurface soils, indicating small localized areas of
contamination. Other than arsenic, none of the analytes were found to exceed their associated screening
levels in the subsurface soil samples.
AREE 29-4-Disposal Area
The Disposal Area is located near the northeast comer of VHFS, northwest of the Skeet Range (AREE
14). Review of aerial photographs of this area provided evidence of disposal activities as early as 1958.
These signs were visible to various extents as late as 1977. A total of five distinct areas were located
within the Disposal Area, based on ground stains and debris visible in aerial photographs. Two areas
were used for construction debris disposal and are now enclosed within groves of trees. Another area is
an approximately 30-foot wide man-made depression in the ground where water collects after, rain events.
It is not known whether the area was used to obtain fill material or for liquid disposal. The last two sites
appeared as orange-stained areas in historic aerial photographs. These are both currently level and
covered with grass. It is not known what materials, if any, were stored in these areas.
. Surface soil samples were collected at the two construction debris piles and at the three other areas of
potential contamination. Aluminum (85,000 ppm), beryllium (2.15 ppm), and iron (160,000 ppm)
concentrations in surface soil in the area of the former orange mound exceeded residential soil RBCs
(78,000 ppm, 0.15 ppm, and 23,000 ppm, respectively) and maximum background concentrations (20,900
ppm. 2.13 ppm, and 70,800 ppm, respectively). Benzo(a)pyrene (0.1 ppm) slightly exceeded its
residential soil RBC (0.088 ppm) in one surface soil sample collected from the construction debris areas.
Arsenic (up to 13.6 ppm) exceeded its residential soil RBC (0.43 ppm) and maximum background
concentration (4.89 ppm) at the construction debris areas.
HUMAN HEALTH AND ECOLOGICAL RISK ASSESSMENT
A Baseline Risk Assessment (BRA) was conducted as part of the RIs 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 heatth associated with current and potential future (assuming residential development of the prooertv}
exposures to site-related chemicals at the AREEs. The Ecological Risk Assessment (ERA) was conducted
to character^ the potential threats to ecological receptors posed by contaminants at the AREEs °°nducted
The HHRA follows a four-step process:
h!S on ?H 9**™^ fr / P°tpntinl nnnrpm - identifies the contaminants of potential concern
based on their tox.c.ty, frequency of occurrence, and concentration by comparing the mSimtm
concentra ions of detected chemicals with RBCs which are health-protective ™eS
concentratons that are back-calculated using toxicity criteria, a 1x10^target carcinogen^ riS
a 0. 1 hazard quotient (defined below), and conservative exposure parameters;
Exposure Assessment - identifies the potential pathways of exposure, and estimates the
^SS^!^ to which peopie may be exposed as weli as the frequency and
• Toxjcity Assessment - determines the toxic effects of the contaminants; and
• Risk CharactRri7ation - provides a quantitative assessment of the overall current and future risk
to people from,site contaminants based on the exposure and toxicity information.
In! IT* e,Va'Uafted health eff6CtS Which could result from exP°sure to soil, groundwater, surface water
and sed,ment contamination in the Phase I and Phase II reuse areas of VHFS. The HHRA evaS
potential nsks to current workers who could be exposed to contaminants in surface soil, and to curint
* t C°, H bS 6XPOSed t0 ""ta"*""0" in surfa<* soil, surface water, and sediment In aSfflon
V 3ted ,P°tential riSkS t0 hyP°thetical ^ure adult residents who could be exposed to
exoon 't 9r0undwater and surface soil and to hypothetical future child residents who couW be
exposed to contaminants in groundwater, surface soil, surface water, and sediment. Potential risks to future
excavatnn workers who couid be exposed to contaminants in subsurface soil were also evaluated to the
(cancer-related> effects and noncarcinogenic effects (including various impacts on
3S IUfl9S' liVer' ^ Were evaluated in {he HHRA- Carcinogenic effects are
'
tH -
each ARPF Th6 Pr°bf b' *? "^ 3n indiVldUa! Wi" deVel°P ""^ from exposure' to the contaminants from
m
< evaluat.on of noncarcinogenic effects is based on the hazard index (HI), which is the
•« K qU°tientS for individual chemicals- The hazard quotient is a comparison of
l-sPecific chronic exposure doses with the corresponding protective doses derived from health
cntena. The USEPA recommends that remedial actions may be warranted at sites where the carcinogenic
risk to any person is greater than 1x10"* or the HI is greater than 1. A carcinogenic risk of 1x10- means that
there is a potential of one additional person 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 Fommfrfion - 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;
ic 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 frorn exposure to surface soil, surface water and
sediment .contamination in the Phase I and II reuse areas 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 by
-------
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, tnere 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.
i The results of the BRA for the five AREEs are presented in the following paragraphs. A detailed presentation
of the BRA can be found in the final Phase I Reuse Area Rl Report and the final Phase II Reuse Area Rl
Report now available in the Information Repository at the Fauquier County Library.
ARSE 13 ' Sludge Disposal Area
The HHRA determined that site-related contamination at AREE 13 does not pose an unacceptable human
health risk under either current or potential future land-use conditions. Discounting naturally-occurring
metals that were statistically determined to be within background concentrations, the highest estimated
excess lifetime cancer risk (8x10"6) is for child residents exposed to contaminants in surface soil by
incidental ingestion. and the highest noncarcinogenic risk (HI = 10) is for child residents exposed to
contaminants in surface soil by incidental ingestion. The contaminant that drove the elevated HI at AREE
13 is iron which was detected at comparable levels in similar subsurface soil types in background
locations and is, therefore, not site-related. An ERA was not conducted at AREE 13 because all samples
were collected at depths of greater than 6 inches. Based on these results, no further action is
recommended at AREE 13.
AREE 14 - Skeet Range
The HHRA concluded that, under both current and future land-use conditions, site-related contamination
at AREE 14 does not pose an unacceptable human health risk, except for lead 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 (4x1 O^6) is for adult
residents and child residents exposed to contaminants in surface soil by dermal absorption and incidental
ingestion. respectively; and the highest noncarcinogenic risk (HI = 0.8) is for adult residents exposed to
contaminants in surface soil by dermal absorption.
The human health risks associated with exposure to lead contamination in surface soil at AREE 14 were
evaluated using the Integrated Exposure Uptake Biokinetic (IEUBK) Model recommended by USEPA for
evaluating tead exposures for young children in residential settings. The IEUBK Model calculates blood
tead levels which result from exposures to lead which may then be compared to blood lead levels of
toxtcolpgical significance for purposes of risk evaluation. The IEUBK Model run for AREE 14 predicted a
geometric mean blood lead level of 5.2 |ig/dL, with 7.75 percent of the population exceeding the blood
lead level of concern (10 jig/dL). The USEPA currently finds 5 percent of the population exceeding the
blood lead level of concern acceptable. Therefore, the IEUBK Model results indicate that if AREE 14 was
developed for residential use in the future, the lead concentrations in the surface soil may be a potential
problem for young children.
The ERA determined that surface soil at AREE 14 does not pose significant potential adverse ecological
effects.
The potential adverse effects to child residents were driven by the presence of lead above the USEPA
screening level for lead in residential soil of 400 ppm at two locations in the Miss Zone. The extent of lead
contamination in the two locations that drove unacceptable human health risks was further investigated
during the SRI. Soil in those two locations was excavated, and the sample results from the remaining soil
show that lead concentrations do not exceed the USEPA screening level for lead in residential soil. Thus,
no further action is recommended at AREE 14 because the unacceptably high lead concentrations were
-------
removed during the SRI. A detailed presentation of the investigation, of lead hot spots at AREE 14 can be
found in the draft SRI Report now available in the Information Repository at the Fauquier County Library.
AREE 16-1-Possible Firefighter Training Pit
Results of the HHRA indicate that, under both current and future land-use conditions, the risks to workers,
trespassers and residents are acceptable 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 (9X1Q-5) is for adult
residents and child residents exposed to site-related contaminants in surface soil by dermal absorption
and incidental ingestion, respectively; and the highest noncarcinogenic risk (HI = 1) is for child residents
exposed to site-related contaminants in surface soil by incidental ingestion. Although the total HI equals 1,
the His recalculated by target organ/critical effect are all less than 1. No significant potential for adverse
ecological effects were found in the ERA. Based on these results, no further action is recommended at
AREE 16-1.
AREE 27 - AAFES Service Station
Results of the HHRA suggested that site-related contamination at AREE 27 does not pose an
unacceptable human health risk under either current or future land-use conditions. Discounting nature ly-
occurring metals that were statistically determined to be within background levels, the highest estimated
upper-bound excess lifetime cancer risk (7x1 Vs) is for child residents exposed to contaminants in surface
soil by dermal absorption, and the highest noncarcinogenic risk (HI = 2) is for child residents exposed to
site-related contaminants in surface soil by dermal absorption. When recalculated by target organ/cr.tica
effect the HI equals 1.3 for the kidneys, primarily as a result of exposures to chromium in surface soil at
AREE 27 Although not all chromium present at AREE 27 will be hexavalent chromium (i.e., the most
toxic form of chromium), the conservative toxicity criterion for hexavaient chromium was used in the
HHRA. Therefore, a HI of 1.3 calculated using conservative toxicity criteria is considered acceptable.
As explained in the AREE 14 discussion, lead contamination in surface soil at^AREE 27 was evaluated
using the IEUBK Model which predicted a geometric mean blood lead level of 3.2 ug/dL with 0.77 percent
of the population exceeding the blood lead level of concern (10 MQ/dL). Again, the USEPA currently finds
5 percent of the population exceeding the blood lead level of concern acceptable. Therefore, the surface
soil lead concentrations at AREE 27 are unlikely to have an adverse effect on the exposed child resident
population.
The ERA determined that site-related contaminants at AREE 27 posed no significant potential for adverse
ecological effects.
Based on these results, no further action is recommended at AREE 27.
AREE 29-4 - Disposal Area
The HHRA determined that site-related contamination at AREE 29^ does not pose an unacceptable
• I man^hTa.thdsk under either current or future land-use conditions. ««^^™S
metals that were statistically determined to be within background concentrations, the highest estimated
^^u^SJTliwJcanoer risk (3x10*) is for child residents «^^ co^^ts mw^
so? by incidental ingestion, and the highest noncarcinogenic risk (H! = 1) « for chikInjwdente exposed {o
site-related contaminants in surface soil by incidental ingestion. .^V^ "**S^E29i £S
potential adverse ecological effects are not posed by the site-related contam.nants at AREE 29-4. Based
on these results, no further action is recommended at AREE 29-4.
PREFERRED ALTERNATIVE
No further action is recommended by the U.S. Army as the preferred «^!^^^13^
and 29-4 because these sites do not pose unacceptable human health or ecological risks. The
cost to implement this alternative is $0.
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