PB99-963910
                              EPA541-R99-014
                              1999
EPA Superfund
      Record of Decision:
      USA Vint Hill Farms Station
      AREEs 2, 4, 28-5, & 31
      Warrenton, VA
      7/1/1999

-------

-------
 FINAL
 DECISION DOCUMENT
 AREEs 2, 4, 28-5, AND 31
 VINT HILL FARMS STATION
 WARRENTON, VIRGINIA
Prepared for:
U.S. Army Communications-Electronics Command
Prepared by:
IT Corporation
Edgewood, Maryland
June 1999

-------

-------
                                  TABLE OF CONTENTS

Section                                                                   Page
1.0  INTRODUCTION	1

2.0  SITE BACKGROUND	1

3.0  SITE CHARACTERISTICS	4
       3.1 Site Topography	4
       3.2 Adjacent Land Use	4
       3.3 Surface Water Hydrology	4
       3.4 Geology/Hydrogeology	4

4.0  SITE HISTORY AND INVESTIGATION FINDINGS	5
       4.1 AREE 2 - Sewage Treatment Plant	5
       4.2 AREE 4 - Auto Craft Shop	5
       4.3 AREE 28-5 - Former Service Station Abandoned USTs	8
       4.4 AREE 31 - Construction Debris Pile #1	8

5.0  SUMMARY OF SITE RISKS	•.	8
       5.1 AREE 2 - Sewage Treatment Plant	12
       5.2 AREE 4 - Auto Craft Shop	12
       5.3 AREE 28-5 - Former Service Station Abandoned USTs	13.
       5.4 AREE 31 -Construction Debris Pile #1	13

6.0  REMEDIAL ACTION OBJECTIVES...	14

7.0  CLEANUP LEVELS ESTABLISHED FOR THE SELECTED ALTERNATIVE	14

8.0  SUMMARY OF REMEDIAL ALTERNATIVES	14
       8.1 Alternative 1 - No Action	16
       8.2 Alternative 2 - Soil Removal	16

9.0  EVALUATION OF ALTERNATIVES	;	16
       9.1 Overall Protection of Human Health and the Environment	17
       9.2 Compliance with ARARs	17
       9.3 Long-term Effectiveness and Permanence	17
       9.4 Reduction of Toxicity, Mobility, or Volume Through Treatment	•.	17
       9.5 Short-term Effectiveness	.s.	:	17
       9.6 Implementability	18
       9.7 Cost	18
       9.8 Regulator Acceptance	18
       9.9 Community Acceptance	18

10.0 SELECTED REMEDY AND STATUTORY DETERMINATIONS	:	18
       10.1  Selected Remedy	18
       10.2  Statutory Determinations	18
                10.2.1  Protection of Human Health and the Environment	19
                10.2.2  Compliance with ARARs	19
                10.2.3  Cost-Effectiveness	-...'.	19
                10.2.4  Utilization of Permanent Solutions and Alternative Treatment Technologies or
                       Resource Recovery Technologies to the Maximum Extent Practicable	19
                10.2.5  Preference for Treatment as a Principal Element	20

-------
                            TABLE OF CONTENTS (CONTINUED)

Section
11.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION...	     ~S3&      2Q

12.0 RESPONSIVENESS'SUMMARY	.	
       12.1  Selected Newspaper Notices	l'l""."."""!..".l.".."...l"..	21
       12.2  Comments Raised During the Public Meeting on April 9 1998     	71
       12.3  Public Meeting Attendance Roster	]	'	~i
       12.4  Restorat'on Advisory Board Members	'".!"!""!"!.'.".'.".'"""!.""'!	21

13.0 REFERENCES	                       22

-------
                                    LIST OF FIGURES

Eiaurg                                                                            Page

1    General Location of VHFS	      2
2    General Locations of AREEs at VHFS	!Z"!""""""!!!!!!!Z"!!""Z"s
3    SI and Rl Sample Locations for AREE 2 - Sewage Treatment Plant	.."    6
4    SI and Rl Sample Locations for AREE 4-Auto Craft Shop	"".'.'".'.".7
5    SI and R! Sample Locations for AREE 28-5 - Former Service Station USTs	'.'.'.'.'.'.'.9
6    Rl Sample Locations for AREE 31 - Construction Debris Pile #1	"I! 10
                                     LIST OF TABLES

Table                                                                             Paqe

1   Cleanup Levels Established for Soil at the Four AREEs	15
                                  LIST OF ATTACHMENTS
Attachment 1          Proposed Plan
Attachment 2          Cleanup Level Development Documents
Attachment 3          Public Notice

-------
                              ABBREVIATIONS AND ACRONYMS
 ARAR        applicable or relevant and appropriate requirement
 AREE        Area Requiring Environmental Evaluation
 bgs          below ground surface
 BRA          Baseline Risk Assessment
 BRAG        Base Realignment and Closure
 CECOM       Communications-Electronics Command
 CERCLA      Comprehensive Environmental Response, Compensation, and Liability Act
 CERFA       Community Environmental. Response Facilitation Act
 CFR          Code of Federal Regulations
 DD           Decision Document
 EEQ          environmental effects quotient
 ENPA        Enhanced Preliminary Assessment
 ERA          Ecological Risk Assessment
 ERC          Environmental Restoration Company
 FS           Feasibility Study
 ft             feet
 HHRA        Human Health Risk Assessment
 HI            Hazard Index
 HQ           Hazard Quotient
 ICF KE        ICF Kaiser Engineers, Inc.
 IEUBK        Integrated Exposure Uptake Biokinetic
 MSL          mean sea level
 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
 STP          sewage treatment plant
TPH          total petroleum hydrocarbon
TRV          toxictty 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
VAC          Virginia Administrative Code
VDEQ         Virginia Department of Environmental Quality
VHFS         Vint Hill Farms Station
VPDES        Virginia Pollutant Discharge Elimination System
                                            IV

-------
                         DECLARATION FOR THE DECISION DOCUMENT
                             REMEDIAL ALTERNATIVE SELECTION
 Site Name and Location

 Areas Requiring Environmental Evaluation (AREEs) 2, 4, 28-5, and 31
 Vint Hill Farms Station
 Warrenton, Virginia

 Statement of Basis and Purpose

 This Decision Document (DD) presents the selected remedial action for soil at AREEs 2,4, 28-5  and 31 at Vint
 Hill Farms Station (VHFS), Warrenton, Virginia, chosen in accordance with the Comprehensive Environmental
 Response, Compensation, and Liability Act of 1980 (CERCLA), as amended by the Superfund Amendments
 and Reauthorization Act (SARA) of 1986 and, to the extent practicable, the National Oil and Hazardous
 Substances Pollution Contingency Plan (NCP), 40 C.FIR. Part 300.. This document was prepared as a joint
 effort between the U.S. Army, the Virginia Department of Environmental Quality (VDEQ)  and the U S
 Environmental Protection Agency (USEPA). The remedial action decision is based on documents contained
 in the Information Repository.

 Assessment of the AREEs

 Actual or threatened releases of hazardous substances from AREEs 2, 4, 28-5, and 31, if not addressed by
 implementing the remedial action selected in this DD, may present an imminent and substantial endangerment
 to public health, welfare, or the environment.

 Description of the Selected Remedy

 This action addresses the principal threat at AREEs 2, 4, 28-5, and 31 by the excavation of contaminated  soil
 and off-site disposal at a permitted facility.

 Statutory Determinations

 The selected remedy is protective of human health and the environment,  complies with Federal and state
 requirements that are legally applicable or relevant and appropriate to the remedial action, and is cost-effective.
 This remedy utilizes permanent solutions and alternative treatment technologies to the maximum extent
 practicable for AREEs 2, 4,28-5, and 31. However, because treatment of the principal threat at AREEs 2,4,
28*6, and 31 was not found to be practicable, this remedy does not satisfy the  statutory preference for treatment
 as a\ principal element of the remedy. A five-year review will not be necessary for AREEs 2, 4, 28-5, and 31
 sine* the seletgdren ed  involves the removal of contaminated soil to risk-based cleanup levels.
\~
ROBERT L. NA30RS
Major General, USA
Commanding
U.S. Army Communications-Electronics Command
Date

-------

-------
                                     DECISION SUMMARY


1.0 INTRODUCTION

        The remedial action decision is based on the Phase II Reuse Area Remedial Investigation (Rl) Report
(USAGE, 1999) which includes a Baseline Risk Assessment (BRA) documenting the risks from contamination
in the soils at Areas Requiring Environmental Evaluation (AREEs) 2, 4, 28-5, and 31.  In the BRA, it was
determined that the soils at AREEs 2,4, and 31 pose unacceptable risks to human health and the environment.
In addition, total petroleum hydrocarbon (TPH) concentrations in soil at AREE 28-5 exceed the Virginia TPH
soil action level for underground storage tanks (USTs). Therefore, the soils at AREEs 2,4,28-5, and 31 require
remedial action to be protective of human health and the environment.

        A feasibility study (FS), which develops and examines remedial action alternatives for a site, was
performed for AREEs 2, 4, 28-5, and 31 and presented in the Proposed Plan (see Attachment 1).


2.0 SITE BACKGROUND

        Vint Hill Farms Station (VHFS) is part of the U.S. Army Communications - Electronics Command
(CECOM) and, while  active, primarily functioned as  an Army installation  engaged  in communications
intelligence. VHFS is located approximately 40 miles southwest .of Washington, D.C., in Fauquier County,
Virginia, as  shown on Figure 1. The installation occupies approximately 701 acres of land near the town of
Warrenton, Virginia.  Approximately 150 acres of the installation are improved grounds in the southern portion
of the property used for industrial operations, administration buildings, and residential housing. Approximately
94 acres in the eastern portion of the property are mature hardwood forest, and the majority of the remaining
457 unimproved and semi-improved acres in the northern portion of the property are used for stationary and
mobile antenna operation sites.

        VHFS was designated for closure in March, 1993, under the Base Realignment'and Closure (BRAC)
Act. Pursuant to the decision to close the installation, an Enhanced Preliminary Assessment (ENPA) and a
Community Environmental Response Facilitation Act (CERFA) investigation of VHFS were conducted  by
Science Applications International Corporation (SAIC) to assess the environmental condition of the installation.
The ENPA and CERFA investigations were completed in April and May, 1994, respectively. The ENPA identified
42 AREEs from the review of installation records, aerial photographs, installation personnel interviews, federal
and state regulatory records, and visual inspection. Of these 42 AREEs, 27 were recommended for further
investigation.                                                                            .

        These 27 AREEs were investigated from September, 1994, to June, 1995, as part of the Site Inspection
(SI) conducted by SAIC. The objective of the SI was to determine the presence or absence of contamination
and the chemical  nature of any detected contamination. The final SI  Report (USAEC, 1996), which was
completed in June, 1996, identified 24 AREEs which required further investigation. In addition, four new AREEs
were identified during site reconnaissance to warrant further investigation subsequent to the SI. AREEs that
were determined to warrant further investigation and are located in the Phase II reuse area (shown on Figure
2) were investigated between February and April, 1997, as part of the Phase II reuse area Rl conducted by ICF
Kaiser Engineers, Inc. (ICF KE). The purposes of the Rl were to evaluate:  1) the nature  and extent of
contamination; and 2) the level of risk posed to human health and the environment  The final Rl Report for the
Phase II reuse area (USAGE, 1999) was completed in January, 1999.

        Four AREEs were identified in the Rl as having soil contamination which poses unacceptable human
health risks and/or significant adverse ecological effects:

        •   AREE 2 - Sewage Treatment Plant;

-------
 JEFFERSOl
 (W. Va.)
                                         HOWARD
                   BALTIMORE
  •.•
                                                           CALVERT ^
                                                                   !•«>. •- •« j.
                          V-:
                                       CHARLES
FAUQUIER
  V    STAFFORD
                                                     ST. MARY'S
                            KING GEORGE
          FIGURE 1
 GENERAL LOCATION
        OF VHFS
10
                             SCALE IN MILES

-------
         LEGEND
    ROAD
  - ' STREAM
    PHASE 1 1 REUSE AREA
AREEs:
2) SEWAGC TREA1 Mf.NT PLANT
4) AUTO CRAFT SHOP
^FORMER SERVICE STATION ABANDONED USTs
  CONSTRUCTION DEBRIS PILE H1
         FIGURE 2
GENERAL LOCATIONS
  OF AREEs AT VHFS

-------
        •  AREE 4 -Auto Craft Shop;

        •  AREE 28-5 - Former Service Station Abandoned USTs; and

        •  AREE 31 - Construction Debris Pile #1 .
The locations of these AREEs are shown on Figure 2.


3.0 SITE CHARACTERISTICS

3.1 Site Topography


thP PAH M™F TJ? ' *Can d W1-hin thu6 Piedmont Plateau Physiographic province, approximately 20 miles west of
nHhP p-prf     t off Une,? a P^^raPf"0 boundafy tha* separates the folded and faulted crystSeTocks
of the Piedmont Plateau physiographic province from the unconsolidated sediments of the Aflantic Coasta*
Plain Phys.ograph.c provmce. The topography of the Piedmont Plateau in the vicinity of VHFS coSs of gentiv

                                than 1 o%- surface eievations
                                         - surface eievations °n

 3.2 Adjacent Land Use


        Land use in the immediate vicinity of VHFS consists mainly of agriculture (mostlv horse
 resident*  areas. With the exception of a few residences to the north, the%oToW8Sa75™n
 » 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 drainage ditches, as shown on Figure 2. South Run is a small Class III Wgin a sTeam

        SSI SSSS* int° L3kf MJT/SaS' 3 reCfeati0n and drinking Water rese™r bu t on9B oa?Ru^
        £l«  ^n  Manassas  Lake Manassas discharges to  Broad Run, which drains to the Occoquan
        Kettle R,n ^OS*** for.JeoSOU?orn P^m °f the installati°n flows south and east to Kettle Run.
        Kettle Run converges with Broad Run approximately 10 miles downstream from Lake Manassas.

 3.4  Geology/Hydrogeology


 whirh ™t»°8n?" 3l ^5™ °f ViHFS JS underiain bV folded sedimentary rocks of the Catharpin Creek Member
 nnihp^ ?   °f sandstone arkos,c sandstone, siltstone, shale, and claystone. Intrusions of basalt, oriented
 northeas 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 presen along the
 major drainage channels within the installation.
nnr«,                    thickest (20-40 ft) in the southern regions of the site and thins to 0-1 0 ft in the
Sie ^nderI8nnS^rn°^  K  H " Tf15 f*™"* of saProlite 
-------
 4.0 SITE HISTORY AND INVESTIGATION FINDINGS
       •       '  for these four AREEs was conducted to evaluate the nature and extent of contamination
 associated with past site activities. Environmental samples collected and analyzed during the Rl were used in
 conjunction with the results from the SI to assess the condition of each of the AREEs  The environmental
 media investigated included surface  soil  (0 to 2 ft below ground surface  [bgs]), subsurface soil  (2 ft to
 approximately 10 ft bgs), surface water, sediment,  and groundwater.  Analytical results were  compared to
 background concentrations and regulatory screening  levels to determine if environmental media had been
 adverse y impacted by site activities. A brief description of each of the four AREEs and the significant findings
 of the Rl and SI are presented in the following paragraphs. A detailed presentation of the samples collected
 and the analytical results can be found in the Phase II Reuse Area Rl Report (USAGE, 1999)  available in the
 Information Repository.

 4.1  AREE 2 - Sewage Treatment Plant
  n/LJcr      2 is fte Sewa9e treatment plant (STP) which serves permanent residents and daily employees
 f   wuco     been in Service Since 195Z  The plant has treated sanitary wastewater, industrial wastewater
 from VHFS operations (photographic, painting, laboratory, vehicle washing, and metal etching), and surface
 water runoff.  The facility discharges treated effluent to South  Run under a  Virginia Pollutant Discharae
 Elimination System (VPDES) permit. Before 1980, sludge was stored in piles on the ground near South Run.

 ADCC  Surface soil, subsurface soil, sediment, surface water, and groundwater samples were collected at
 AKEE 2 as shown on  Figure 3.  Metals were  detected in surface soil above residential soil risk-based
 concentrations (RBCs) established by U.S. Environmental Protection Agency (USEPA) Region III for screenina
 analytical results. Mercury (maximum concentration of 4.3 parts per million [ppm]) was detected above the
 residential soil RBC of 0.78 ppm in surface  soil samples SS-02-001. and SS-02-002  Benzo(a)pyrene a
 polynuclear aromatic hydrocarbon (PAH), was present above residential soil RBCs in one surface soil sample
 downgradient of the former sludge pile. Based on the results of the subsurface  soil samples subsurface soil
 has not been impacted by AREE 2 activities.                                         '

 4.2 AREE 4 - Auto Craft Shop


        The Auto Craft Shop (Buildings 306 and 308) was used as the motor pool from 1943 to 1 967 and as
 a0Voo!C le ™aintenance area where military personnel performed maintenance on their private vehicles from
 1 968 to 1 994. The buildings were used to store oil, solvents, and lubricants for vehicle maintenance activities
 as well as spent solvent and waste oil filters.  The buildings have concrete floors with no curbs or floor drains
 Gasoline and oil spills have been recorded in this area and were cleaned up using absorbents A 1 000-gallon
 UST was used to store waste oil prior to its  removal in July, 1990. A plume  of petroleum contamination
 currently lies under the shop as a result of leaks from the UST.  A corrective action for this plume has been
 implemented. Three areas where surface runoff/discharge from AREE 4 occurs have been identified (see
 Figure 4). An outdoor vehicle wash rack near Building 308 drained into a grit chamber which has been
 removed.  The grit chamber was used to settle the solids prior to discharge of water from the vehicle wash rack
 via a ceramic pipe into the wooded area south of Building 308. The floor of the grit chamber and the associated
 contaminated soil were removed during the Phase II reuse area Rl field investigation. A storm sewer drain
 located west of Buildings 306  and 308 discharged surface runoff to the  field south of the Auto Craft Shop
 Surface runoff also drains south of the Auto Craft Shop near the former hydraulic lift.

       Surface soil, subsurface soil, and groundwater samples were collected at AREE 4 as shown on Figure
4.  Surface and subsurface soil results are presented herein; groundwater results are presented in a separate
Decision Document (DD) which addresses site-wide groundwater. TPH contamination, exceeding the Virginia
TPH soil action level for USTs of 100 ppm, was present in surface soil samples collected near the storm sewer
discharge area, former hydraulic lift surface runoff area, and wash rack discharge area. The maximum TPH
concentration (1 ,860 ppm) was detected in surface soil sample SS-04-002 collected at the former hydraulic

-------
                                                                  UNNAMED TRIBUTARY
                                                                  TO SOUTH RUN
                                                                                       RISW2-2
                                                                                       RISED2-2
              SEWACE TREATMENT
                        PLANT
                 GROUNOWATER
                 ROW     \
                 OIRECTON \
                                                                                                   SOIL LOCATIONS
                                                                                            (RISS2HANO RISS2-2) ARE
                                                                                            CO-LOCATH! WITH THE SOIL
                                                                                            BORING LOtXnSJjS (RJSB2-1
                                                                                            AND RISS2-2).
                                                                                          2. MONITORING WELL NUMBERS
                                                                                            2MW-1 THROUGH 2MW-3 HAVE
                                                                                            SEEN MODIFIED FROM THE
                                                                                            NUMBERS  REPORTED IN THE
                                                                                            ORIGINAL HELD INVESTIGATIONS
                                                                                            IN ORDER  TO PROVIDE UNIQUE
                                                                                            WELL NUMBERS FOR THIS
                                                                                            REPORT.
                       ..IMPACTED SURFACE SOIL AREA
                                     (APPROXIMATE)
                                          .BUILDING
                                     .VHFS  BOUNDARY
                                       .PAVED ROAD
                                            .FENCE
                                          ..STREAM
                                         ..TRIBUTARY
                      .TOPOGRAPHIC CONTOUR (FT  MSL)
                    .SI SURFACE SOIL SAMPLE LOCATION
                           .EXISTING MONITORING WELL
                        .PHASE II Rl MONITORING WELL
O	PHASE II Rl SOIL 30RING LOCATION
P..PHASE II Rl  SURFACE WATER/SEDIMENT SAMPLE LOCATION
               RGURE 3
Sf AND Rl SAMPLE LOCATIONS
     FOR AREE 2-SEWAGE
       TREATMENT PLANT

-------
          SS-04-00

           R1SB+-1
                                                      RE84-6
                                                       RE84-7
                                                       SS-04-
                                                                                    FCRMER GRIT
                                                                                    CHAMBER
                          GROUNOWATER ^
                          ROW DIRECTION
                          (BASED ON AREE 4 WELLS)
                                                           RE84-
                                                      SS-04-003

                                                           RISB4-
NOTES:
 1. SURFACE SOIL SAMPLE LOCATIONS (RISS4-3 THROUGH
      RBS4-11) ARE CO-LOCATED WITH THE SOIL BORING
      LOCATIONS (RISB«-J THROUGH RES4-I1).
    2. UONTORING waL NUMBERS 4UW-1 THROUGH 4MW-J
      HAVE BEEN UODIREO FROU THE NUMBERS REPORTED
      THE ORIGINAL FIELD INVESTIGATIONS IN ORDEH TO
      PROVIDE UNIQUE WELL NUMBERS FOR THIS REPORT.
                                                   APPROXIMATE AREA
                                                   OF EXCAVATION
 LEGEND:
       	IMPACTED SURFACE SOIL AREA
                             (APPROXIMATE)
-x—x-	FENCE
••	BUILDING
=====	.,	ROAD
""=	STORM DRAIN
,--4IO^__	TOPOGRAPHIC  CONTOUR (FT MSL)
Q	SI  SOIL SORING LOCATION
•	SI SURFACE  SOIL  SAMPLE LOCATION
O	PHASE II Rl  SOIL  BORING LOCATION
®.	EXISTING  MONITORING WELL
•$:	PHASE  II Rl  MONfTORING WELL
                                                   SCALE IN  FEET
                                                                                           FIGURE 4
                                                                            SI AND Rl SAMPLE LOCATIONS
                                                                                        FOR AREE 4 -
                                                                                   AUTO CRAFT SHOP

-------
 lift surface runoff area. Metals were detected in surface soil above residential soil RBCs at all three surface
 runoff/discharge areas. Lead contamination exceeding the USEPA screening level for lead in residential soil
 of 400 ppm was detected in surface soil at all three surface runoff/discharge areas.  The maximum lead
 concentration (1,700 ppm) was detected in a surface soil sample collected from the storm sewer discharoe
 area.  Four PAHs (benzo[a]anthracene, benzofajpyrene, benzo[b]fluoranthene, and indenofl 2 3-cd]Dvrenei
 exceeding the residential soil RBCs are present in surface soil at the wash  rack discharge area   Onlv
 benzo(a)pyrene is present in surface soil above the residential soil RBC (0.087 ppm) in all three surface
 runoff/discharge areas. The maximum benzo(a)pyrene concentration of 1.52 ppm was detected in surface soil
 sample RISS4-5 located in the wash rack discharge area. Based on the results of the subsurface soil samples
 from the three surface runoff/discharge areas, contaminant concentrations in subsurface soil were all below
 screening levels.

 4.3  AREE 28-5 - Former Service Station Abandoned USTs
                                      t
        AREE 28-5 consists of the Former Service Station Abandoned USTs located under the asphalt parking
 lot approximately 60 ft northwest of the former service station (Building 220).  Three 5,000-gallon steel USTs
 were used for the storage of gasoline and diesel fuel products. The USTs were approximately 30 years old and
 were in service until 1983.  Environmental Restoration Company (ERG) removed the USTs and associated
 pipelines in December, 1994.

        Subsurface soil and groundwater samples were collected at AREE 28-5 as shown on Figure 5  TPH
 contamination, exceeding the Virginia TPH soil action level for USTs of 100 ppm, was detected in subsurface
 soil in the vicinity of the former pump island at depths ranging from 2 ft bgs to at least 10 ft bgs The maximum
 TPH concentration (5,273 ppm) was detected at a depth of'8-10 ft bgs in soil boring RISB28-5-1.

 4.4 AREE 31 - Construction Debris Pile #1

       AREE ai  is a construction  debris pile  located  approximately 200 to 300 ft northwest of the
 southernmost tip of the VHFS property boundary in a predominantly wooded and vegetated area  The pile
 consists of construction debris including, but not limited to, concrete pipe, corrugated steel pipe steel footers
 antennae pillars, roofing paper, bricks, cinder blocks, cement slabs, and insulation material  The debris pile
 has an area of approximately 15  ft by 150 ft.

       Surface and subsurface (from a test pit) soil samples were collected at AREE 31 as shown on Figure
 6. Metals (copper and lead) and PAH contamination is present in surface soil sample RISS31-2.  The lead
 concentration of 3,610 ppm exceeded the USEPA screening level for lead in  residential  soil of 400 ppm
 Copper at  1,880 ppm  exceeded its  residential soil RBC  of 310 ppm.  Five PAHs (benzofajanthracene
 benzo[b]fluoranthene, benzo[k]fluoranthene,  benzo[a]pyrene,  and indenofl ,2,3-cd]pyrene)  exceeded the
 residential soil RBCs by one or more  orders of magnitude in surface soil sample RISS31-2.  For example
 benzo(a)pyrene was detected at 34.6 ppm compared to its residential soil RBC of 0.087 ppm. Subsurface soil
 has not been impacted by the debris present at AREE 31.


 5.0 SUMMARY OF SITE RISKS

       A BRA was conducted as part of the Rl to assess the human health and ecological problems that could
 result if the contamination at the AREEs was not remediated. The Human Health Risk Assessment (HHRA)
was prepared to evaluate the magnitude of potential adverse effects on human health associated with current
industrial/commercial and potential future residential exposures to site-related chemicals at the AREEs. The
Ecological Risk Assessment (ERA) was conducted to characterize the potential threats to ecological receptors
posed by contaminants at the AREEs.

-------
         GEOPHYSICAL AND
         SOIL ORGANIC VAPOR
         SURVEY AREA
           ASSUMED
           GROUNDWATER
           FLOW DIRECTION
                                                                                                          1
 LEGEND:
 ESSJIMPACTED SOIL.AREA (APPROXIMATE)
 ^m	BUILDING
         '	PAVED ROAD
 -*10^..TOPOGRAPHIC CONTOUR (R MSL)
 •36	UST na PIPE
• I      i.	.FORMER UST LOCATION
 ©	SI SOIL BORING LOCATION
 •$-	PHASE II Rl MONITORING WELL
 O....PHASE II Rl SOIL BORING LOCATION
    10
           20
SCALE IN FEET
               FIGURE 5
SI AND Rl SAMPLE LOCATIONS
   FOR AREE 28-5 - FORMER
    SERVICE STATION USTs

-------
                                                       APPROXIMATE  LOCATION
                                                       OF CONSTRUCTION
                                                       DEBRIS  PILE #1
             IMPACTED SURFACE SOIL AREA
                         (APPROXIMATE)

                         VHFS BOUNDARY
                           PAVED ROAD
•x— x — x- ................................. FENCE

--- 420 --- ......... TOPOGRAPHIC CCJffOUR (FT MSL)

       ........ PHASE I! Rl TEST PIT LOCATION

       ......... PHASE  II R! TEST PtT SAMPLE
                .PHASE
                       Ri SURFACE SOIL
                       SAMPLE LOCATION
                                          SCALE IN FEET
               FIGURE 6

     Rl SAMPLE LOCATIONS
FOR AREE 31 - CONSTRUCTION
         DEBRIS PILE #1
                                                    10

-------
        The HHRA follows a four-step process:

        •   Selection of Chemicals of Potential Concern - identifies the contaminants of potential concern
            based on their toxicity, frequency of occurrence, and concentration by comparing the maximum
            concentrations  of  detected  chemicals with  RBCs  which are  health-protective  chemical
            concentrations that are back-calculated using toxicity criteria, a 1x10"6 target carcinogenic risk or
            a 0.1 hazard quotient (HQ, defined below), and conservative exposure parameters;

        •   Exposure Assessment  - identifies the potential  pathways of exposure,  and estimates the
            concentrations of contaminants to which people may be exposed as well as the frequency and
            duration of these exposures;

        •   Toxicitv Assessment - determines the toxic effects of the contaminants; and

        •   Risk Characterization - provides a quantitative assessment of the overall current and future risk
            to people from site contaminants based on the exposure and toxicity information.

        The HHRA evaluated health effects which could result from exposure to soil, groundwater surface
water, and sediment contamination in the Phase II reuse area of VHFS. The HHRA evaluated potential risks
to current workers who could be exposed to contaminants in surface soil, and to current trespassers who could
be exposed  to 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 only 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
expressed as the probability that an individual will develop cancer from exposure to the contaminants from each
AREE. The  evaluation of noncarcinogenic effects is based on the hazard index (HI), which is the summation
of the HQs for individual chemicals. The HQ is a comparison of chemical-specific  chronic exposure doses with
the corresponding protective doses derived from health criteria. The USEPA recommends that remedial
actions may  be warranted at sites where the carcinogenic risk to any person is greater than 1 x10"4 or the HI is
greater than 1. A carcinogenic risk of 1x10"4 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 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;

       •    Ecotoxicologic Effects Assessment - identifies concentrations or doses of contaminants that are
           protective of indicator species; and
                                               11

-------
         •   Risk Characterization - estimates potential adverse effects from exposure to contaminant-;
            on exposure and toxicity information.

         The ERA evaluated ecological effects which could result from exposure to surface soil surface watPr
 and sediment contamination in the Phase II reuse area of VHFS. The ERA evaluated potential adverse'
 ecological effects to terrestrial plants and terrestrial invertebrates (represented by earthworms) exposed to
 contaminants in surface soil.  In addition, potential adverse ecological effects to mammals (represented bv
 shrews) and  birds (represented  by robins) through  bioaccumulation in the food web and  exposure to
 contaminants in surface soil were evaluated. Potential adverse ecological effects to aquatic life from exposure
 to contaminants in surface water and sediment were also evaluated in the ERA. Further the potential adverse
 ecological effects  to  mammals (represented  by minks) and  birds  (represented 'by  herons)  through
 bioaccumulation in the food web and exposure to contaminants in sediment were evaluated.

        The evaluation of significant potential adverse ecological effects is based on the Environmental Effects
 Quotient (EEQ). The EEQ is the ratio of the estimated exposure concentrations/doses for the chemicals of
 potential concern and the toxicity reference values (TRVs) for the ecological receptors. If the EEQ is greater
 than 1, there is a potential for adverse ecological effects to occur. As the magnitude of the EEQ becomes
 greater than 1, the potential for adverse ecological  effects becomes more significant.

        The results of the BRA for the four AREEs are presented in the following paragraphs   A detailed
 presentation of the BRA can be found in the Phase II Reuse Area Rl Report (USAGE 1999) available in the
 information Repository.

 5.1 AREE 2 - Sewage Treatment Plant


        The HHRA determined that, under both current industrial/commercial and potential future residential
 land-use conditions, the risks to workers, trespassers, residents, and excavation workers are acceptable for
 exposure to site-related contaminants at AREE 2. Discounting naturally-occurring metals that were statistically
 determined to be within background concentrations,  the highest estimated upper-bound excess lifetime cancer
 risk (1X10'3) is for child residents exposed to site-related contaminants'in surface soil by incidental ingestion
 and the highest noncarcinogenic risk (Hl=5) is for child residents exposed to site-related contaminants in
 surface soil by incidental ingestion. The contaminant that drove the elevated HI at AREE 2 is iron which was
 detected at comparable levels in similar surface soil types in background locations and is therefore  not site-
 related.

        The ERA determined that contaminants in surface soil at AREE 2 pose significant potential adverse
 ecological effects. The significant potential adverse ecological effects result primarily from mercury. Mercury
 results in significant potential adverse ecological effects for terrestrial plants, earthworms, robins, and shrews
with the greatest potential adverse ecological effects occurring to robins (EEQ of 3,500).

        The mercury contamination downgradient of the former sludge pile is recommended for remediation.
 The impacted area has approximate dimensions of 75 ft by 25 ft by 2 ft deep, as shown on Figure 3.

 5.2 AREE  4 - Auto Craft Shop

        The HHRA concluded that, under both current industrial/commercial and potential future residential
 land-use conditions, the risks to workers, trespassers, residents, and excavation workers are acceptable for
exposure to site-related contaminants, except for lead, in soil at AREE 4. 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 site-related contaminants in surface
soil by incidental ingestion,  and the highest noncarcinogenic risk (HN0.5) is for child residents exposed to site-
related contaminants in surface soil by dermal absorption.
                                               12

-------
         The human health risks associated with exposure to lead contamination in surface s
  e,rsinH9 the integrfed Exposure uptake Biokinefc  M°dei i^s^n
  evaluating lead exposures for young children in residential settings. The IEUBK Model calculates
  levels which result from exposures to lead which may then be compared to blood °ead te^^
  significance for purposes of risk evaluation. The IEUBK Model run for AREE 4 predated a geomeric     ,
  ? 10  o dL?  TH  HK P   nta' C0n°%n W6re identified in subsurface so" ^ AREE 28-5 in the HHRA. However risS
 associated with exposures to TPH  could not be assessed in the BRA because  this analyticalVarametel
 represents a mixture of chemical constituents. Since TPH measurements give no in Jcaton oHhe cheS
 constrtuents present or their respective concentrations, they cannot be used to pfJSS^^SToSSlSte
 Dumo SandTARFF?«n;0t ^ ?*£*?' ™ Contamination in subsurfa<* «« 'n the vicinity of thefo mer
 forTpm^? /   ?h       f ? 6dS the Virg'nia TPH S0il action ievel for USTs and fe- therefore/recommended
 for remediaton. The ,mPacted area is approximately 20 ft x 20 ft x 1 0 ft deep (minimum), as shown on Figure
 5.4 AREE 31 - Construction Debris Pile #1
^ri,QroIh^ ?HRA determined that. under current industrial/commercial land-use conditions, the risks to
workers and trespassers are acceptable for exposure to contaminants in surface soil at AREE 31   Under
potential future residential land-use conditions, assuming that AREE 31 is not remediated, the risks to potential
adult and child residents are unacceptable for exposure to contaminants in surface soil at AREE 31  The
highest estimated upper-bound excess lifetime cancer risk is for child residents exposed to contaminants in
surface soil by mcidental ingestion; this risk is 4x1 rj4 (i.e., 4 in 1 0,000 residents may develop cancer cTused by
exposure to contam.nants in surface soil at AREE 31).  Cancer risks were due primarily to exposures to
benzo(a)pyrene and other PAHs. Discounting naturally-occurring metals that were statistically determined to
be within background  concentrations, the  highest noncarcinogenic risk is for child  residents exposed to
contaminants in surface soil by incidental ingestion; the HI is estimated to be 0.7.

       As explained in the AREE 4 discussion, lead contamination in surface soil at AREE 31 was evaluated
using the IEUBK Model which predicted a geometric mean blood lead level of 15 ^g/dL, with 78 4 percent of
the population exceeding the blood lead level of concern (10 ng/dL).  Again, the USEPA currently finds 5
percent of the population exceeding the blood lead level of concern acceptable.  Therefore the IEUBK Model
                                              13

-------
 results indicate that if AREE 31 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 contaminants in surface soil at AREE 31 pose significant potential adverse
 ecological effects. The significant potential adverse ecological effects result primarily from metals (copper
 lead, mercury, and selenium) and one PAH (benzo[a]pyrene). Mercury results in significant potential adverse
 ecological effects for robins and shrews, with the greatest potential adverse ecological effects occurring to
 robins (EEQ of 250).  Copper results in significant potential adverse ecological effects for terrestrial plants and
 earthworms, with the greatest potential adverse ecological effects occurring to earthworms (EEQ of  38)
 Selenium and lead result in significant potential adverse ecological effects for terrestrial plants with EEQs of
 25 and 72, respectively. Benzo(a)pyrene results in significant potential adverse effects to earthworms with an
 EEQ of 13.

        The most significant contamination at AREE 31 is in surface soil in the vicinity of surface soil sample
 RISS31-2 located in the northeastern portion of the debris pile, which is recommended  for remediation  The
 impacted area has approximate dimensions of 50 ft x 15 ft x 2 ft, as shown on Figure 6.


 6.0  REMEDIAL ACTION OBJECTIVES

        Remedial action objectives are specific goals to protect human health and the environment  The
 remedial action objective for the four AREEs is to minimize the potential for contaminated  soil to pose
 unacceptable risks to human or ecological receptors.


 7.0  CLEANUP LEVELS ESTABLISHED FOR THE SELECTED ALTERNATIVE

        USEPA has established soil cleanup levels for the contaminants that contribute to the unacceptable
 risk determination at each of the four AREEs. The soil cleanup levels are presented  in Table 1  The soil
 cleanup level for AREE 2 is based on concentrations which are protective of ecological  receptors (EEQ=10)
 The soil cleanup level for lead in surface soil  at AREEs 4 and 31  is based on the USEPA screening level for
 lead in residential soil of 400 ppm. The soil cleanup levels for other metals at AREE 4 are based on
 concentrations which are protective of ecological receptors. The soil cleanup level for AREE 28-5 is based on
 A^L9,inia TPH S0il acti°n  levl' for USTs Of10° ppm' USEPA established the soil  cleanup levels for PAHs
 at AREE 31 based on a 1X10  (one in 1,000,000 people) upper-bound excess lifetime cancer risk for the
 potential future residential use scenario. The soil cleanup levels for metals, other than lead  at AREE 31 are
 based on concentrations which are protective  of ecological receptors.


 8.0 SUMMARY OF REMEDIAL ALTERNATIVES

       Two remedial alternatives were evaluated to address soil contamination at AREEs 2, 4  28-5 and 31
 The range of remedial alternatives considered was limited by the nature and  extent of  the contamination Since
the amount of soil requiring  remediation is relatively small (approximately 400 cubic yards), it was not practical
to consider active treatment or containment options in terms of cost-effectiveness and implementability  The
 following remedial alternatives were evaluated:
       •   Alternative 1 - No Action; and
       •   Alternative 2 - Soil Removal.
                                              14

-------
                                           Table 1
                      Cleanup Levels Established for Soil at the Four AREEs
  Constituents
  Mercury (Ecological risk)
                             AREE 2 - SEWAGE TREATMENT PLANT
  Lead (Human Health & Ecological risk)
  Mercury (Ecological risk)
                                 AREE 4 - AUTO CRAFT SHOP
  Selenium (Ecological risk)
  Zinc (Ecological risk) fc)
  TPH
AREE 28-S - FORMER SERVICE STATION ABANDONED USTs
                                          100(e)
  Benzo(a)anthracene (Human Health risk)
                          AREE 31 - CONSTRUCTION DEBRIS PILE #1
  Benzo(a)pvrene (Human Health & Ecological risk)
  Benzo(b)fluoranthene (Human Health risk)
  Ben2o(k)fluoranthene (Human Health risk) fc)
  Copper (Ecological risk)
 Jndenod .2,3-cd)pvrene (Human Health risk)
 Lead (Human Health & Ecological risk)
 Mercury (Ecological risk)
          (Ecological risk)
TPH - total petroleum hydrocarbons
USTs - underground storage tanks
(a) Based on a concentration which is protective of ecological receptors (EEOlO)

  } ™T«n,hfef'th C'eaJ1Up. leVe'S are based on a 1X1°  uPPer-b°und excess lifetime cancer risk for the
   potental future residential land-use scenario.
(c) These compounds contribute to but do not drive unacceptable risk
(d) USEPA screening level for lead in residential soil.
(e) Virginia TPH soil action level for USTs.
                                            15

-------
 8.1 Alternative 1 - No Action

        The National Oil and Hazardous Substances Pollution Contingency Plan (NCP) and Comprehensive
 Environmental Response, Compensation, and  Liability Act (CERCLA),  as amended by the Superfund
 Amendments and Reauthorization Act (SARA), require that a No Action alternative be considered as a baseline
 for comparison to other alternatives.  No action would be taken to address site contamination  under this
 alternative. In accordance with Section 121 of CERCLA, each AREE would be reviewed at least once every
 five years to re-evaluate site conditions and to determine the need for remedial action to protect human health
 and the environment.

 8.2 Alternative 2 - Soil Removal

        Under this alternative, all  contaminated soil exceeding the established cleanup levels would be
 excavated, transported off site by truck, and disposed using a combination of permitted off-site hazardous
waste, construction debris, and/or municipal landfills, as appropriate based on analytical results. Approximately
 400 cubic yards  of impacted soil would be excavated as part of this alternative,  followed by  confirmation
 sampling to assure adequate removal of all soil exceeding the cleanup levels. Upon completion of the soil
 excavation, disturbed areas would be backfilled, regraded, and either vegetatively stabilized or paved (AREE
28-5). The five-year review does not apply to this alternative because hazardous substances above risk-based
 cleanup levels would not remain on site.


 9.0 EVALUATION OF ALTERNATIVES

        CERCLA requires a comparison of the alternatives using nine evaluation criteria: overall protection
of human health and the environment; compliance with applicable or relevant and appropriate requirements
 (ARARs); long-term effectiveness and permanence; reduction of toxicity, mobility or volume through treatment;
short-term effectiveness; implementability; cost; and regulator and community acceptance. The first two criteria
are considered by USEPA to be threshold criteria which must be met by each alternative.  The nine evaluation
criteria are described below:

        •       Overall protection of human health and the environment addresses whether or not a remedy
               provides adequate protection and describes how  risks posed through each  pathway are
               eliminated, reduced, or controlled through treatment, engineering controls, or institutional
               controls.

        •       Compliance with ARARs addresses whether or not a remedy will meet all of the  applicable
               or relevant and appropriate requirements of other federal and state environmental statutes
               and requirements or provides grounds for invoking a waiver.

        •       Long-term effectiveness and permanence refers to the ability of a remedy to maintain reliable
               protection of human health overtime, once cleanup goals have been met.

        •       Reduction of toxicitv. mobility, or volume through treatment is the anticipated performance of
               the treatment technologies a remedy may employ.

        •       Short-term effectiveness addresses the period of time needed to achieve protection and any
               adverse impacts on human health and the environment that may  be posed during the
               construction and implementation period until cleanup goals are achieved.

       •       Implementsbilitv is the technical and administrative feasibility of a  remedy, including the
               availability of materials and services needed to implement a particular option.


                                              16

-------
                 0* includes estimated capital and operation and maintenance costs, and net present worth
                           '^ a"emal*"is ""' """"a* based upon these evalua«on cmeria, and „

  9.1  Overall Protection of Human Health and the Environment
                                                                              onment
 9.2 Compliance with ARARs
                                              ^
 monitored during excavation activities to assure Taccepte Tbte air aualiS  AL^     ^ C°ndltions would b«
 monitoring, water sprays would be used to ^keep dus? level^                 "^ aSed °n ^ ambient air

 9.3  Long-term Effectiveness and Permanence
 9.4 Reduction of Toxicity, Mobility, or Volume Through Treatment
9.5 Short-term Effectiveness
                                           the short term because the volume of soil to be excavated
                                           -" impacts to human health or the environment.  Dust
                                             17

-------
 exposure to workers and adjacent residents would be controlled during excavation activities by water sprays
 as needed. Prior to excavation operations, temporary erosion control structures would be installed to prevent
 entry of storm water into the soil excavation areas and prevent erosion and movement of soil from contaminated
 areas. Although truck traffic would be increased during implementation of Alternative 2 the implementation
 period (approximately one month) is short and the number of trucks per day would be less than 20.

 9.6 Implementability


        Alternative 2 is considered readily implementable.  Licensed transporters and permitted disposal
 facilities are currently available.                                                             H

 9.7 Cost

        The cost to implement Alternative 2 is estimated at $260,000.

 9.8 Regulator Acceptance

        VDEQ and USEPA concur with the selected remedy.

 9.9  Community Acceptance


        A public meeting on the Proposed Plan was held on April 9,1998, in Warrenton, Virginia  Comments
 received dunng the public meeting and the public comment period are referenced in the Responsiveness
 Summary (Section 12 of this DD).


 10.0 SELECTED  REMEDY AND STATUTORY DETERMINATIONS

 10.1 Selected Remedy


        Following review and consideration of the information in the Information Repository requirements of
 CERCLA and the NCP, and the review of public comments on the Proposed Plan the U S  Armv  in
 coordination with VDEQ and USEPA, has selected Alternative 2, Soil Removal, as the remedy for the
 contaminated soil at AREEs 2, 4, 28-5, and 31.

       Under this remedy, all contaminated soil exceeding the established cleanup levels would be excavated
transported off site by truck, and  disposed using  a  combination of  permitted  off-site hazardous waste'
construction debris, and/or municipal landfills, as appropriate based on  analytical results. Approximately 400
cuhc yards of impacted soil would be excavated as part of this remedy, followed by confirmation sampling to
assure adequate removal of all soil exceeding the cleanup levels (refer to Table 1). Upon completion of the
fAli!nCoVation' disturbed areas would be backfilled, regraded, and either vegetatively stabilized or paved
(AREE 28-5).

       The estimated cost to implement this remedy is $260,000, and the on-site activities would require
approximately one month to complete.

10.2 Statutory Determinations

       Under CERCLA Section  121, selected remedies must be protective  of human health and the
environment, must comply with ARARs (unless a statutory waiver is justified), must be cost-effective, and must
utilize permanent solutions and alternative treatment technologies or resource recovery technologies to the
maximum extent practicable. In addition, CERCLA includes a preference for remedies that employ treatment

                                              18

-------
 that permanently and significantly reduces the volume, toxicity, dr mobility of hazardous waste as their principal
 element. The following sections discuss the remedy in light of these statutory requirements.

         10.2.1 Protection of Human Health and the Environment

         The selected  remedy would protect  human health and  the environment. All contaminated soil
 exceeding the established cleanup levels will be removed and disposed of in permitted, off-site facilities. The
 cleanup levels listed in Table 1 were developed to be protective of human health and the environment.

         Short-term risks would be present as a result of dust exposure to workers and adjacent residents, soil
 erosion and sedimentation during excavation activities, and transport of contaminated soil off site. These risks
 would be acceptable as a result of control measures which would be implemented during the remedial action.
 These control measures include use of water sprays during excavation operations to control dust, and use of
 silt fences and other erosion control techniques to control erosion and soil movement from contaminated areas.
 The increase in truck traffic would be minimal, with the addition of less than 20 trucks per day over the course
 of approximately one month.

         10.2.2 Compliance with ARARs

         The selected remedy will be in full  compliance with ARARs:

 •       9 Virginia Administrative Code (VAC) 20-80-10 et seq.: Virginia Solid Waste Management Regulations
         - the disposal  of any soil, debris, sludge or any other solid waste must be done in compliance with the
         regulations;

 •       9 VAC 20-60-10 et sea.: Virginia Hazardous Waste Management Regulations  - the disposal of any
         hazardous waste must be done in compliance with the regulations;

 •       4 VAC 50-30-10, et seq.:  Virginia Erosion and Sedimentation Control Regulations - an erosion and
         sedimentation control plan that complies with the minimum design and implementation standards of
         the regulations will be prepared before engaging in any land disturbing activity;

 •       9 VAC 5-10-10 through 9 VAC 5-80-350: Regulations of the Virginia Air Pollution Control Board -
         ambient air monitoring will be used to determine  the need for water sprays to control dust generation
         in order to comply with ambient air quality standards for particulate matter.

         10.2.3 Cost-Effectiveness

         The selected  remedy affords overall  effectiveness proportional to its costs. All contaminated soil
 exceeding the established cleanup levels will be removed from AREEs 2, 4,28-5, and 31. The entire remedy
 will be achieved for approximately $260,000..

         10.2.4 Utilization of Permanent Solutions and Alternative Treatment Technologies or
                Resource Recovery Technologies to  the Maximum Extent Practicable

         The selected remedy utilizes permanent solutions to the maximum extent practicable while providing
 the best balance among the other evaluation criteria. It achieves the best balance of tradeoffs  with respect to
 the primary balancing  criteria of long-term effectiveness  and permanence; reduction of toxicity, mobility, and
 volume through treatment; short-term effectiveness; implementability; and cost; while also considering regulator
 and community acceptance.

         The selected  remedy provides a high degree of long-term effectiveness and permanence as the
 removal and off-site disposal of the contaminated soil would be permanent and irreversible. The variety of
 contaminants present in the soil at AREEs 2, 4, 28-5, and 31 and the relatively small volume of contaminated
. soil cause on-site treatment technologies to be impracticable and not cost-effective. The selected remedy is
                                                19

-------
easily implementable, with a relatively short time frame needed for design development. There is minimal risk
to the community during the implementation of the selected remedy, and the slight risks to the environment can
be reduced by implementing standard procedures, such as erosion and sedimentation controls.

       10.2.5 Preference for Treatment as a Principal Element

       Because treatment of the principal threat at AREEs 2,4,28-5, and 31 was not found to the practicable,
this remedy does not satisfy the statutory preference for treatment as a principal element of the remedy.


11.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION

       The Proposed Plan for AREEs 2, 4, 28-5, and 31 was released to the public on March 26, 1998 (see
Attachment 1).  This document was made available for public review in the Information Repository at the
following location:

                                    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 3) was published in The Fauauier
Citizen, the Fauauier Times-Democrat, and the Manassas Journal Messenger during the week of March 23,
1998. A public comment period was held from March 26,1998, through April 24,1998.  In addition, a public
meeting was held on April 9,1998, to present the Proposed Plan for AREEs 2, 4,28-5, and 31 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  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 Fauauier Citizen, the Fauquier Times-Democrat, and the Manassas Journal
Messenger, and place the DD in the Information Repository.


12.0 RESPONSIVENESS SUMMARY

       The purpose of this Responsiveness Summary is to provide the public with a summary of citizen
comments, concerns, and questions about AREEs 2, 4, 28-5, and 31.  A public meeting was held on April 9,
1998, 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
March 26,1998, through April 24,1998, comment period.

       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 9, 1998;

       •       Public meeting attendance roster; and

       •       Restoration Advisory Board Members.


                                              20

-------
  12.1 Selected Newspaper Notices





  12.2 Comments Raised During the Public Meeting on April 9, 1998


                                         " ***** ^^ The ^Z^S «™«™ and ** "• S- A-y's

  CONCERNED CITIZEN: Is AREE 31 located directly under the trees or beyond the stand of trees?

  ARMY RESPONSE: AREE 31 is located within the tree line.

  12.3 Public Meeting Attendance Roster
                                                            «" 8*-.
 12.4 Restoration Advisory Board Members

 1 .  Debra Reedy, Community Co-Chair
 2.  Richard Reisch, U.S. Army Co-Chair
 3.  Dean Eckelberry
 4.  John Mayhugh
 5.  Jeff Lippincott
 6.  Owen Bludau
 7.  Tim Tarr
 8.  NorrisGoff
 9.  Erich Meding
 10. Kevin Bell
 11. Mark Stevens
 12. Nancy Inger
 13. Joanne Smith
 14. Henry Ross
 15. Steve Mihalko
 16. Robert Stroud
 17. Steve Maddox
 1 8.  William Downey
 19.  GinaTyo
 20.  Joe Phelan
 21.  MikeMolloy
 22.  Denny Adams
 23. JoeWiltse
 24.  Bob Root
 25.  Georgia Herbert
 26.  Robert Kube
 27.  Kim berly Davis
 28.  George Rosenberger
29.  Adrienne Garreau
                                           21

-------
30.  Susan Dove
31.  James Tucker
32.  John Williams


13.0 REFERENCES

U.S. Army Corps of Engineers (USACE). 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.
                                              22

-------
 ATTACHMENT 1




PROPOSED PLAN

-------

-------
  Proposed Plan
                                    AREEs 2, 4, 28-5, and 31
                                Vint Hill Farms Station, Virginia
                                                                                   March 1998
  INTRODUCTION
                                             in 
iS
                           °" site-related documents contained in the VHFS Information Repository  The

                                y°" W"h 'mPOrtant Inf°rmafa1 3b°Ut ^ *e a"d 'he ** «^'  £
                                     Fauquier County Library
                               Warrenton Branch - Reference Section
                                1 1 Winchester Street, Warrenton, VA
                                         (540)347-8750
                            Monday - Wednesday: 10:00 a.m. to 9:00 p.m.
                             Thursday - Saturday: 9:00 a.m. to 5:00 p.m.
                                  Sunday: 1:00 p.m. to 5:00 p.m.
 The US .Army needs your comments and suggestions. The U.S. Army, the U.S. Environmental Protection
 Agency (USEPA) Region 111, and the Virginia Department of Environmental Quality (VD^S)uS^Se
 pubte to revew and comment on both of the alternatives presented in the Proposed Plar^ ^ The public
                                                  on April 24,  199,  P,eaSe send your
                                  Kevin Bell, Public Affairs Officer
                                  Public Affairs Office (Bldg..2500)
                                      Vint Hiils Farm Station
                                   Warrenton, VA 20187-5001
   teAR&             p                     S investi9aton and dea™P of contamination at the
 selected AREEs at VHFS.   Representatives  from  the U.S. Army will  report on  cleanuo  alternative
 cons,dered and the U.S. Army's preferred alternative. The meeting is scheduled for         P  alternat'Ves
                                Thursday, April 9,  1998 at 7:00 p.m.
                                Warrenton Middle School Auditorium
                                244 Waterloo Street, 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
 ™™T     I -I™37, Tdi1V the Preferred  aKernative 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
^rinn°^«mThent 3KSr the Pubiic,comment Period nas ended and the comments and information submitted
dunng that time have been reviewed and considered.
       *ni  , jf ui"S this Proposed Plan as part of its public participation responsibilities under Sections
       and 117(3) of the Comprehensive  Environmental Response,  Compensation,  and  Liability Act

-------
 (CERCLA). as amended, commonly known as the "Super-fund Program",  and the National Environmental
 Policy Act of 1969 (NEPA).  This Proposed Plan focuses on AREEs 2, 4, 28-5, and 31. 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) and while active
 primarily  functioned  as  an  Army installation engaged in communications  intelligence.  VHFS  is located
 approximately 40 miles southwest of Washington,  D.C., in Fauquier County, Virginia, as shown ort 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 (BRAC)
 Act, Pursuant to the decision to close the installation, an Enhanced Preliminary Assessment (ENPA) and a
 Community Environmental Response  Facilitation  Act (CERFA) investigation of VHFS were conducted  by
 Science Applications International  Corporation  (SAIC) to assess  the  environmental condition of  the
 installation.  The ENPA and CERFA investigations were completed in April and May, 1994, respectively  The
 ENPA identified 42 AREEs from the review of installation records,  aerial photographs, installation personnel
 interviews, federal and state regulatory records,  and  visual  inspection.   Of these 42 AREEs  27 were
 recommended for further investigation.

 These 27 AREEs were investigated from September, 1994,  to June, 1995, as part of the Site Inspection (S!)
 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 and are located  in the  Phase II  reuse area  (shown  on  Figure 2)  were
 investigated between February and April, 1997, as part of the Phase II reuse area Remedial Investigation
 (Rl) conducted by ICF Kaiser Engineers, Inc. (ICF KE).  The purposes  of the Rl were to evaluate-  1) the
 nature and extent of contamination; and 2) the level of risk posed to human health and the environment  The
 draft Rl Report for the Phase II reuse area was completed in January, 1998, and is currently undergoing
 regulatory review.                                                                          s   s

 Four AREEs were identified  in the Rl as  having soil contamination  which poses unacceptable human health
 risks and/or significant adverse ecological effects:

        •       AREE 2 - Sewage Treatment Plant;
        •       AREE 4 - Auto Craft Shop;

        •       AREE 28-5  - Former Service Station Abandoned  Underground Storage Tanks (USTsV
               and

        •       AREE 31-Construction Debris Pile#1.
Tne locations of these AREEs are shown on Figure 2.


RESULTS OF THE REMEDIAL INVESTIGATION

The  Rl for  these four AREEs was  conducted  to evaluate the nature  and extent of  contamination
associated with past site activities. Environmental samples collected  and analyzed during the Rl  were
used in conjunction with the  results from the SI to assess the  condition  of each of the AREEs   The
environmental media  investigated included surface soil (0 to 2 feet below ground surface [bgsj)

-------
 JEFFERSOh
 (W. Va.)  (

                                         HOWARD
                          MONTGOMERY
                        MARYLAND
      LOUDOUN
                                                \:  ANNE ARUNDEL
                  VIRGINIA
                            --' V
                            '  WASHINGTON D.C.'~
                     FAIRFAX
       Vint Hill
    Farms Station
               PRINCE WILLIAM
                                         PRINCE GEORGES

                                                          CALVERT
FAUQUIER ... •'  -'
                                      CHARLES
       STAFFORD
                                                     ST. MARY'S
                           KING GEORGE
         FIGURE 1
GENERAL LOCATION
       OF VHFS
            -N-
0   5   10
                            SCALE IN MILES

-------
         LEGEND
    ROAD
 X'' STREAM
         11 REUSE AREA
AREEs:
 2) SEWAGE TREATMENT PLANT
 4) AUTO CRAFT SHOP
  FORMER SERVICE STATION ABANDONED USTs
         FIGURE 2
GENERAL LOCATIONS
 OF APPPc ATX/HCC

-------
subsurface soil  (2  feet to'approximately 10 feet bgs), surface water,  sediment, and groundwater.
Analytical results were compared  to  background concentrations and  regulatory  screening  levels to
determine if environmental media had been adversely impacted by site activities.  A brief description of
each  of the four AREEs  and the significant findings  of the Rl  and SI  are presented in the following
paragraphs. A detailed presentation of the samples collected and the analytical results can be found  in
the draft Phase II Reuse  Area Rl Report, now available in the Information Repository at the Fauquier
County Library.
AREE 2- Sewage Treatment Plant
AREE 2 is the sewage treatment plant (STP) which serves approximately 70 VHFS permanent residents and
500 daily  employees and  has been in service since  1952.  The plant has treated  sanitary  wastewater,
industrial wastewater from  VHFS operations (photographic, painting, laboratory, vehicle washing, and meta!
etching),  and surface water runoff. The facility discharges treated effluent to South Run under a Virginia
Pollutant Discharge Elimination System (VPDES) permit  Before 1980, sludge was stored in  piles on the
ground near South Run.

Surface soil, subsurface soil, sediment, surface water, and groundwater samples were collected at AREE 2
as shown on Figure 3.  Metals were detected in surface soil above residential soil risk-based concentrations
(RBCs) established by USEPA Region III for screening analytical results.   Mercury (4.3 parts per million
[ppm]) was detected  above the  residential soil RBC of 2.3 ppm in surface soil  sample SS-02-002.
Benzo(a)pyrene, a polynuclear aromatic hydrocarbon (PAH), was present above residential soil RBCs in one
surface soil sample downgradient of the former  sludge pile.  Based on the results of the subsurface soil
samples, subsurface soil has not been impacted by AREE 2 activities.

AREE4 • Auto Craft Shop
The Auto Craft Shop (Building 306 and former Building 308) was used as the motor pool from 1943 to 1967,
and as a vehicle maintenance area where military personnel performed maintenance on their private vehicles
from 1968 to 1994. The buildings were used to store oil, solvents, and lubricants for vehicle maintenance
activities as well as spent solvent  and waste oil filters.  The buildings have concrete floors with no curbs or
floor drains. Gasoline and oil spills have been recorded in this area and were cleaned up  using absorbents.
A 1,000kjallon UST was used to  store waste oil prior to its removal in July, 1990.  A plume  of petroleum
contamination currently lies under the shop as a result of leaks from  the UST.  A corrective action for this
plume has been implemented.  Three areas where surface runoff/discharge from AREE 4 occurs have been
identified (see Figure 4). An outdoor vehicle wash rack near former Building 308 drained into a grit chamber,
which  has been removed.  The grit chamber was used to settle the solids prior to discharge of water from the
vehicle wash rack via a ceramic pipe into the. wooded area south of former Building 308.  The Moor of the grit
chamber  and 'the associated  contaminated soil were removed during the Phase II reuse area Rl field
investigation. A storm sewer drain located west of Building 306 and former Building 308 discharged surface
runoff to the field south of the Auto Craft Shop. Surface runoff also drains south of the Auto Craft Shop near
the former hydraulic lift.
Surface soil, subsurface soil, and groundwater samples were collected at AREE 4 as shown on Figure 4.
Total petroleum hydrocarbon (TPH) contamination, exceeding the Virginia TPH soil action level for USTs of
100 ppm, was present in surface soil samples collected near the  storm  sewer discharge: area, former
hydraulic lift surface runoff area, and wash rack discharge area.  The maximum TPH concentration (1,860
ppm) was detected in surface soil  sample SS-04-002 collected at the former hydraulic lift surface runoff area.
 Metals were detected in surface soil above residential soil RBCs at al! three surface runoff/discharge areas.
Lead  contamination exceeding the USEPA screening level for lead in residential soil of 400  ppm was
detected in surface soil at  all three surface runoff/discharge areas. The maximum  lead concentration (1,700
ppm) was detected in a surface soil sample collected from the storm sewer discharge area.  Four PAHs
(benzo[a]anthracene,  benzo[a]pyrene,  benzo[b]fluoranthene,  and indeno[1.2,3-cdjpyrene) exceeding the
residential soil RBCs are present in surface soil at the wash rack discharge area.  Only benzo(a)pyrene is
present in surface soil above the residential soil RBC (0.088 ppm) in all three surface runoff/discharge areas.
 The maximum benzo(a)pyrene concentration of 1.52 ppm was detected in surface soil sample RISS4-5

-------
                                                                  UNNAMED TRIBUTARY
                                                                  TO SOUTH RUN
                                                                                                  SOIL LOCATIONS
                                                                                                  AND RISS2-2) ARE
                                                                                                     WITH THE  SOIL
                                                                                            BORING LOCATKKjS (RISB2-1
                                                                                            AND R1S82-2).
                                                                                          1 UONITORING WELL NUMBERS
                                                                                            2UW-1 THROUGH 2UW-3 HAVE
                                                                                            BOH MODIFIED FROM THE
                                                                                            NUMBERS REPORTED IN  THE
                                                                                           ORIGINAL HELD !NVEST1GATIONS
                                                                                           IN ORDER TO PROVIDE UNIQUE
                                                                                            WELL NUMBERS FOR THIS
                                                                                           REPORT.
LEGEND:
O-
	IMPACTED SURFACE SOIL AREA
                 (APPROXIMATE)
	BUILDING
	VHFS BOUNDARY
	PAVED ROAD
	FENCE
	STREAM
	TRIBUTARY
....TOPOGRAPHIC CONTOUR (FT MSL)
. SI SURFACE SOIL SAMPLE LOCATION
	EXISTING MONITORING WELL
	PHASE II Rl MONITORING WELL
.PHASE II Rl SOIL BORING LOCATION
                                                                  100
                                                     SCALE IN FEET
               RGURE 3
SI AND Rl SAMPLE LOCATIONS
     FOR AREE 2-SEWAGE
       TREATMENT PLANT
0..PHASE II Rl  SURFACE WATER/SEDIMENT SAMPLE LOCATION

-------
                                                                          FORMER
                                                                          HYDRAULIC LIFT
                                                      RIS84-6
                                                       RE84-7
                                                      "SS-04-
                                 FORMER GRtT
                            :—CHAMBER
                           GROUNDWATER
                           ROW DIRECTION
                           (BASED ON'AREE 4 WELLS)
          MW4

     RISB4-

SS-04-003

     RISB4-

     R1S84-3
    I. SURFACE SOIL SAMPLE LOCATIONS (HSS4-3 THROUGH
      RSS4-11) ARE CO-LOCATED WTO THE SOIL BORING
      LOCATIONS (RIS8<-3 THROUGH R1S84-11).
    2. MONITORING WEIL NUMBERS 4MW-1  THROUGH 4MW-3
      HAVE BEEN MODIFIED FROU THE NUMBERS REPORTED
      "HE ORIGINAL FIELD INVESTIGATIONS IN ORDER TO
      PROVIDE UNIQUE WELL NUMBERS FOR THIS REPORT.
APPROXIMATE AREA
OF EXCAVATION
               IMPACTED SURFACE SOIL AREA
                             (APPROXIMATE)
~x—*-.	FENCE
^•H	BUILDING
=====	ROAD
= ----	STORM DRAIN
-—410	.TOPOGRAPHIC  CONTOUR (FT MSI)
®	SI SOIL BORING LOCATION
•	SI SURFACE SOIL  SAMPLE LOCATION
O	PHASE d Rl SOIL  BORING'LOCATION
®.	EXISTING MONfTORING WELL
•fc	PHASE II Rl MONITORING WELL
 SCALE IN FEET
                                        FIGURE 4
                         SI AND Rl SAMPLE LOCATIONS
                                     FOR AREE 4 -
                                AUTO CRAFT SHOP

-------
  SSS 'n th™aSH faCk dischar9e area Based on 'he results of the subsurface soil samples from the three
  surface runoff/d.scharge areas, subsurface soil has not been impacted by AREE 4 activities.
  AREE 28-5 • Former Service Station Abandoned USTs

  AREE 28-5 consists of the Former Service Station Abandoned USTs located under the asphalt parkina lot
  approximately 60 ft northwest of the  former service station (Building 220).  Three 5 000-gallon steel USTs
  were used for the storage of gasoline and diesel fuel products.  The USTs were app oximltely 30 years Id
  and  were  in serves until 1983.   Environmental Restoration Company (ERC) removed  L USTs an"
  associated pipelines in December, 1994.                                                        na

  Subsurface soil and groundwater samples  were collected at AREE 28-5  as shown on Figure  5  TPH

 ShTfJv ^f tn9 f18 Vir9inia  TPH S0i' aCti°n level for USTs of 10° PPm- was detected in subsurface
 so,l m  the vicinity of the former pump .sland at depths ranging from 2 ft fags to at least 10 ft bqs  The
 maximum TPH concentration (5.273 ppm) was detected at a depth of 8-10 ft bgs in soil boring  RISB28-5-1
 AREE 31 - Construction Debris Pile  #1
 oMh! VHF9 n°nntiCtir *?** ^ ****? ^P™™3'^ 20° to 30° * northwest of the southernmost tip
 of the VHFS property boundary ,n  a  predominantly  wooded and vegetated area.  The pile consists of
 construction debns including, but not limited to. concrete pipe, corrugated steel pipe, steel footers
                     XS        blocks' cement slat* and i                    •
 Surface and subsurface (from a test pit) soil samples were collected at AREE 31 as shown on  Figure 6
 TletadCrnm'Um; ^^n'^ ** PAH ***"***" «« P**"* in surface soi. sample RISS31-2
 The lead concentration of 3,610 ppm exceeded the USEPA screening level for lead in residential soil of 400
 soT iSST1!? a?dQCOpper conflations of 7.59 ppm and 1 ,880 ppm exceeded their respective  residential
 benzo?klunranthP    F™  ^   ™  ^  ^  PAHs  (ben2°[a]anthracene,  benzo[b]fluoranthene
 one 2 mo?I   H   '  ^enz°tato'rene- and indeno[1.2.3-cd]pyrene) exceeded the residential soil RBCs by
 SL.PH a»7^ p5   magnitude In surface soil samP'^ RISS31-2.   For example. benzo(a)pyrene  was-
                                             soil RBC of °-°88 ppm-  subsurface soii has n
HUMAN HEALTH AND ECOLOGICAL RISK ASSESSMENT

                AssmeBRA> .was conducted as part of 'the  Rl to assess the  human health  and
                                  .
     h                            'f the contamination at ^e AREEs was not remediated. The Human
                                                                            .
n    th                       Prep3red t0 SVaIUate the ma9nitude of potential adverse effects on
?       associated with current and potential future (assuming residential development of the property)
PV                                                                                  e propery
to ch^r, f   S' r613 >ted C?lmiCalS 3t the AREES'  The Ecol°9ical Risk Assessment (ERA) was conducted
to characterize the potential threats to ecological receptors posed by contaminants at the AREEs.
The HHRA follow? a four-step process:

       *   Selection of Chemicals of Potential Concern - identities 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 (defined below), and conservative exposure parameters;

       •   Exppsure  Assessment - identifies the potential pathways of exposure,  and estimates  the
           concentrations of contaminants to which people may be exposed as well as the frequency and
           duration of these exposures;

       •   Tpxipitv Assessment - determines the toxic effects of the contaminants; and

       •   Risk Characterisation . provides a quantitative assessment of the overall current and future risk
           to people from site contaminants based  on the exposure and toxicity information.

-------
                                                                                                               1
         GEOPHYSICAL AND
         SOIL ORGANIC VAPOR
         SURVEY AREA
           ASSUMED
           GROUNDWATER
           FLOW  DIRECTION
 LEGEND:
SS3IMPACTED SOIL AREA (APPROXIMATE)
••	BUILDING
.-        	PAVED ROAD
-+10-...TOPOGRAPHIC CONTOUR (FT MSL)
ffl	UST FILL PIPE
      i..'.	FORMER UST LOCATION
®	SI SOIL BORING LOCATION
'$-	..PHASE II Rl MONTORING WELL
O....PHASE II Rl SOIL BORING LOCATION
    10
           20
SCALE IN FEET
               FIGURE 5
SI AND Rl SAMPLE LOCATIONS
   FOR AREE 28-5 - FORMER
    SERVICE STATION USTs

-------
                                                        APPROXIMATE  LOCATION
                                                        OF CONSTRUCTION
                                                        DEBRIS  PILE #1
 LEGEND:
              IMPACTED  SURFACE SOIL AREA
                          (APPROXIMATE)
                         VHFS BOUNDARY
                           PAVED ROAD
 -x— x — x- ................................. FENCE
 — -420 — . ......... TOPOGRAPHIC CONTOUR (FT MSI)
 1    '. .......... PHASE II Rl TEST PIT LOCATION
 A. ................ PHASE II Rl TEST PIT SAMPLE
 •• .................... PHASE II Rl SURFACE SOIL
_ _   SAMPLE LOCATION
            100
SCALE IN FEET
               FIGURES
     Rl SAMPLE LOCATIONS
FOR AREE 31 - CONSTRUCTION
         DEBRIS PILE#1
                                                     10

-------
  current workers who could b^e^sed to^^m^^u^soii'd^S^ ^tia, risks to
  be exposed to contamination in surface soil, surface water, and sediment In additionth^M^^0 COUld
  z^zmxzx^^
  groundwater, surface soil  surface water and sediment  Pntont i  i- »  * exP°sed to contaminants in
  could be exposed to contaminants in subsurface soil were also, evataTed^he HHR?^'0" WWk8r8 Wh°







 noncarcinogenic health effects if the AREE is not remedied.                dlCateS a P°tential tor
 The ERA also follows a four-step process:
                       ^,^^ -
         Exposure ?f*~s*rf nt - estimates exposure point concentrations for selected indicator species-
                        •' ' adverss effects from
                          eer                   ,             •
      fi^si's^scr.isss'i'.-SKisa".;
                                                        .-s s =
  ~~~
AREE 2 - Sewage Treatment Plant



AREE 2. Dscountmg naturally-occurring metals that were statistically determined to be within background
                                  11

-------
concentrations, the highest estimated upper-bound excess lifetime cancer risk (8X10*) is for adult residents
exposed to site-related contaminants in surface soil by dermal absorption, and the highest noncarcinogenic
risk (Hl=0.2) is for child residents exposed to site-related contaminants in surface soil by incidental ingestion.

The ERA determined  that contaminants in  surface soil at AREE  2 pose significant potential adverse
ecological effects.  The significant potential adverse ecological effects result primarily from mercury. Mercury
results in significant potential adverse ecological effects for terrestrial plants, earthworms, robins, and shrews,
with the greatest potential adverse ecological effects occurring to robins (EEQ of 3,500).

The mercury contamination downgradient of the former sludge pile is recommended for remediation.  The
impacted area has approximate dimensions of 75 ft by 25 ft by 2 ft deep, as shown on Figure 3.
AREE 4 - Auto Craft Shop                •

The HHRA concluded that,  under both current and  future  land-use  conditions, the  risks to workers,
trespassers, residents, and excavation workers are acceptable for exposure to site-related contaminants!
except for lead, in soil at AREE 4. Discounting naturally-occurring metals that were statistically determined to
be within background concentrations, the highest estimated upper-bound excess lifetime cancer risk (5X10-5)
is for adult residents exposed to site-related contaminants  in surface soil by dermal  absorption, and the
highest noncarcinogenic risk (Hl=0.3) is for child residents exposed to site-related contaminants  in surface
soil by dermal absorption.

The human health risks associated with exposure to lead contamination in  surface soil at AREE 4 were
evaluated using the Integrated Exposure Uptake Biokinetic (IEUBK)  Model  recommended by USEPA for
evaluating lead exposures for young children in residential settings.  The tEUBK Model calculates  blood lead
levels which result from exposures to lead which may then be compared to blood lead levels of toxicoiogical
significance for purposes of risk evaluation.  The IEUBK Model run for AREE  4 predicted a geometric mean
blood lead level of 6.9 ng/dl_, with 19.81 percent of the population exceeding the blood lead level of concern
(10 ng/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 4 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 metals in surface  soil at AREE 4 pose significant potential adverse  ecological
effects.  The significant potential adverse ecological effects result primarily from lead, selenium, mercury, and
zinc.  Lead, selenium, and zinc result in significant potential adverse  ecological effects to  terrestrial plants
with EEQs of 34, 38, and 15, respectively.  Mercury results in significant potential adverse ecological effects
to robins (EEQ of 210) and shrews (EEQ of  13).

The metals contamination in the surface soil at the three surface runoff/discharge areas is recommended for
remediation. The approximate dimensions of the impacted area at each of the three surface runoff/discharge
areas are 15ftx15ftx2ft deep, as shown on Figure 4.

AREE 28-5 - Former Service Station Abandoned USTs

The  ERA did  not evaluate AREE 28-5 because this  area is covered  with asphalt,  thus eliminating the
potential for exposure to ecological receptors.

The HHRA determined that contamination at AREE 28-5 does not pose an unacceptable human  health risk
under either current or potential future land-use conditions.  In fact, no chemicals of potential concern  were
identified in subsurface soil at AREE 28-5 in the HHRA. However, risks associated with exposures to TPH
could not be assessed in the BRA because this analytical parameter represents a  mixture of chemical
constituents, Since TPH  measurements give no indication of the chemical constituents  present or their
respective concentrations, they cannot be used to predict risks. Although  risks associated with TPH cannot
be estimated. TPH contamination in subsurface soil in the vicinity of the former pump island at AREE 28-5
exceeds the Virginia TPH soil action level for  USTs.and is,  therefore, recommended for remediation.  The
impacted area is approximately 20 ft x 20 ft x 10 ft deep (minimum),'as shown on Figure 5.
                                                12

-------
  AREE 31 - Construction Debris Pile #1

  The HHRA determined that, under current IstHd-use conditions, the risks to workers are unacceptable for
  exposure to contaminants in surface soil at AREE 31.  Under future land-use conditions  assuminq that
  AREE 31  is not remediated,  the risks to potential adult and child residents are  also unacceptable for
  exposure to contaminants in surface soil at AREE 31.  The highest estimated  upper-bound excess lifetime
  cancer nsk is for adult residents exposed to contaminants in surface soil by dermal absorption- this risk is
  1x10  (i.e.,  1 in 1,000 residents may develop cancer caused by exposure to contaminants in surface soil at
  AREE 31).  Cancer nsks were due primarily to exposures to benzo(a)pyrene and other PAHs  The highest
  noncarcinogenic risk is for child residents exposed to contaminants in surface soil by incidental ingestion- the
  HI is estimated  to  be 2, indicating  that adverse effects could  occur if child  residents were exposed  to
  contaminants in  surface soil.  The critical effect caused by exposure to noncarcinogenic contaminants in
  surface soil at AREE 31 is gastrointestinal irritation due to copper and iron (which was statistically determined
  to be within background concentrations).  It should be noted that major uncertainties exist regarding the
  assessment of dermal  absorption exposures (particularly associated with  dermal absorption  factors)-
  therefore, estimated risks are likely to be over-estimated  for the dermal absorption exposure route.

  As explained in the AREE 4 discussion, lead contamination in surface soil at AREE 31 was evaluated using
  the IEUBK Model which predicted a geometric mean blood lead  level of 15 fag/dL, with 78.4 percent of the
  population exceeding the blood lead level of concern (10 ng/dL). Again, 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 31 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 contaminants in surface soil  at AREE 31 pose significant  potential adverse
  ecological effects.  The significant potential adverse ecological effects result primarily from metals (copper
.  lead, mercury, and selenium) and one PAH (benzo[a]pyrene). Mercury results in significant potential adverse
  ecological effects for robins and shrews, with the greatest potential adverse ecological effects  occurring  to
  robins (EEQ of 250).  Copper results in significant potential adverse ecological effects for terrestrial plants
  and earthworms, with the greatest potential adverse ecological effects occurring  to earthworms (EEQ of 38)
  Selenium and lead result in significant potential adverse ecological effects for terrestrial plants with EEQs of
  25 and 72, respectively.  Benzo(a)pyrene results in significant potential adverse effects to earthworms with
  an EEQ of 13.

  The most significant contamination at AREE 31 is in surface soil in the vicinity of surface soil sample RISS31-
  2 located in the northeastern portion of the debris pile, which is recommended for remediation.  The impacted
  area has approximate dimensions of 50 ft x 15 ft x 2 ft, as shown on Figure 6.


  REMEDIAL ACTION OBJECTIVES

  Remedial action objectives are specific goals to protect human health and the  environment.  The remedial
  action objective for the four AREEs is to minimize the potential for contaminated soil to pose unacceptable
  risks to human or ecological receptors.


 CLEANUP LEVELS ESTABLISHED FOR THE PREFERRED ALTERNATIVE

  USEPA has established  soil cleanup levels  for the contaminants that contribute to  the unacceptable risk
 determination at each of the four AREEs. The soil cleanup levels are presented in Table 1. The soil  cleanup
 level for AREE 2 is based on concentrations which are protective of ecological receptors (EEQ=10). The soil
 cleanup level for lead in surface soil at AREEs 4 and 31 is based on the USEPA screening level for lead in
 residential soil of 400 ppm. The soil cleanup levels for other metals at AREE4 are based on concentrations
 which are protective of ecological receptors.  The soil cleanup level for AREE 28-5 is based on the Virginia
 TPH soil action level for USTs of 100 ppm.  USEPA established the soil cleanup  levels for PAHs at AREE 31
 based on  a 1X10"6 (one in 1,000,000 people) upper-bound excess lifetime cancer risk for the potential future
                                                13

-------
                                            Table 1
                       Cleanup Levels Established for Soil at the Four AREEs
Constituents
Cleanup Levels (ppm)
AREE 2 - SEWAGE TREATMENT PLANT
Mercury (Ecological risk)
0.1 92 (a)
AREE 4 -AUTO CRAFT SHOP 	 -j
Lead (Human Health & Ecological risk)
Mercury (Ecological risk)
Selenium (Ecological risk)
Zinc (Ecological risk) (c)
400 (d)
0.534 (a) j
10 (a)
500 (a)
AREE 28-5 - FORMER SERVICE STATION ABANDONED USTs
TPH
100 (e)
j AREE 31 - CONSTRUCTION DEBRIS PILE #1
! Benzo(a)anthracene (Human Health risk)
Benzo(a)pyrene (Human Health & Ecological risk)
Benzo(b)fluoranthene (Human Health risk)
; Benzo(k)fluoranthene (Human Health risk) (c)
Copper (Ecological risk)
! lndeno(1,2.3-cd)pyrene (Human Health risk)
Lead (Human Health & Ecological risk)
j Mercury (Ecological risk)
Selenium (Ecological risk)
0.87 (b) |
0.087 (b) I
0.87 (b)
8-7 (b) .;;
500 (a)
0.87 (b) |
400 (d) ;
0.48 (a)
10 (a) j
TPH - total petroleum hydrocarbons
USTs - underground storage tanks
(a) Based on a concentration which is protective of ecological receptors (EEQ=10).
(b) Human health cleanup levels are based on a 1X10"6 upper-bound excess  lifetime  cancer risk for the
   potential future residential land-use scenario.
(c) These compounds contribute to but do not drive unacceptable risk.
(d) USEPA screening level for lead in residential soil.
(e) Virginia TPH soil action level for USTs.
                                               14

-------
 residential use scenario.  The soil cleanup levels for metals, other than lead, at AREE 31  are  based on
 concentrations which are protective of ecological receptors.


 SUMMARY OF REMEDIAL ALTERNATIVES

 Two remedial alternatives were evaluated to address soil contamination at AREEs 2, 4, 28-5 and 31  The
 range of remedial alternatives considered was limited by the nature and extent of the contamination  Since
 the amount of soil requiring  remediation is relatively small  (approximately 400 cubic yards) it was not
 practical  to  consider  active  treatment  or containment options in terms  of  cost-effectiveness and
 implementability. The following remedial alternatives were evaluated:
        •   Alternative 1 - No Action; and

        •   Alternative 2 - Soil Removal.
 Alternative 1 - No Action

 The National Contingency  Plan (NCR) and CERCLA, as amended  by the Superfund  Amendments and
 Reauthonzation Act (SARA), require that a No Action alternative be considered as a baseline for comparison
 to other alternatives.  No action would be taken to address site contamination under this alternative   In
 accordance with Section 121 of CERCLA, each AREE would be'reviewed at least once every five years to
 re-evaluate site conditions and to determine the need for remedial  action to protect human health and the
 environment.

 Alternative 2 • So/7 Removal

 Under this alternative, all contaminated soil exceeding the established cleanup  levels would be excavated
 transported  off site by truck, and  disposed using a  combination  of •permitted off-site  hazardous waste'
 construction debris, and/or municipal  landfills or incinerators, as appropriate based on analytical results '
Approximately 400 cubic yards of impacted soil would be excavated as part of this alternative, followed  by
 confirmation sampling to assure adequate removal of ail soil exceeding the cleanup levels.  Upon completion
of the soil excavation, disturbed areas would be backfilled, regraded,  and either vegetatively stabilized or
 paved (AREE 28-5). The five-year review does not apply to this alternative because hazardous substances
 above risk-based cleanup levels would not remain on site.


 EVALUATION OF ALTERNATIVES

CERCLA requires a comparison of the alternatives using nine evaluation criteria:  overall protection  of human
health and the environment; compliance with applicable or relevant  and appropriate requirements  (ARARs);
long-term  effectiveness and permanence;  reduction of toxicity, mobility or volume through treatment;  short-
term effectiveness; implementability; cost; and regulator and community  acceptance. The first two criteria
are considered by  USEPA to be threshold criteria which must be  met by each  alternative.   The nine
evaluation criteria are described below:

               Overall protection of human health and the environment addresses whether or not  a remedy
               provides adequate protection and describes how  risks posed  through each  pathway  are
               eliminated, reduced, or controlled through treatment,  engineering controls, or institutional
               controls.

       •       Compliance with ARARs addresses whether or not a remedy will meet all of the applicable
               or relevant and appropriate requirements of other federal and state  environmental statutes
               and requirements or provides grounds for invoking a waiver.

       •       Long-term  effectiveness and permanence refers  to  the ability of  a remedy to maintain
              , reliable protection of human health over time, once cleanup goals have been met
                                               15

-------
        •       Reduction of toxicitv. mobility, or volume through .treatment is the anticipated performance of
                the treatment technologies a remedy may employ.

        •       Short-term effectiveness addresses the period of time needed to achieve protection and any
                adverse impacts on human health and the  environment that may  be posed during the
                construction and implementation period until cleanup goals are achieved.

        •       Implemeptgbility is  the technical and administrative feasibility of a remedy, including the
                availability of materials and services needed to implement a particular option.

        •       Cost includes estimated capital and operation  and maintenance  costs,  and net present
                worth costs.

        •       Regulator acceptance indicates whether,  based on their review of the Rl and Proposed
                Plan, the regulators (VDEQ and USEPA) concur, oppose, or have no comment on the
                preferred alternative at this present time.

        •       Community acceptance will be assessed in the Decision Document following a review of the
                public comments received on the Rl and the Proposed Plan.

The comparative analysis of the alternatives was conducted based upon these  evaluation criteria and is
described below.

Overall Protection of Human Health and the Environment

The no action alternative (Alternative 1) is not protective of-human  health or the  environment because the
risks to potential future residents and the potential adverse effects to ecological receptors remain unchanged,
which is unacceptable. Therefore, the no action alternative was eliminated from further consideration and will
not be discussed further.

Alternative 2 provides adequate protection of human health and the environment by removing contaminated
soil, thereby eliminating the potential for exposure.
Compliance with ARARs

Alternative 2 has  been  designed to achieve or comply  with ARARs.   This alternative will  satisfy the
established cleanup  levels since all soil that is contaminated above applicable cleanup  levels will be
removed.  In addition, the removal and disposition of contaminated soil during implementation of Alternative 2
would be_done in accordance with federal and Virginia solid and hazardous waste regulations.  During soil
excavation. Virginia Regulations for the  Control and Abatement of Air Pollution may apply.  Ambient air
conditions would be monitored during excavation activities to assure acceptable air quality.  As necessary
based on the ambient air monitoring,  water sprays would be used to keep dust levels down.
Long-term Effectiveness and Permanence

Alternative 2 would provide for the permanent removal of contaminated soil to a permitted off-site location
designed to prevent contaminant migration and exposures to human and ecological receptors.
Reduction of Toxlcity, Mobility, or Volume Through Treatment

Alternative 2 provides reduction of contamination at the AREEs by removing contaminated  soil. The toxicity
and volume of the contaminated soil would not be affected by this alternative;  however, the mobility of the
contaminants would be reduced because the off-site disposal  facilities  used would  be designed to prevent
contaminant migration.

Because treatment of the contaminated soil at the AREEs was not found to be  practicable due to the small
volume of impacted soil, Alternative  2 does not satisfy the statutory preference for treatment as a  principal
element of the remedy.
                                                16

-------
 Short-term Effectiveness  .

 Alternative 2 is considered  to be effective in the short term because the volume of soil to be excavated is
 relatively small and would  result in limited negative impacts to human health or the environment.  Dust
 exposure to workers and adjacent residents would be controlled during excavation activities by water sprays
 as. needed. Prior to excavation operations, temporary erosion control structures would be installed to prevent
 entry of storm water into  the  soil excavation  areas  and prevent erosion and  movement of  soil from
 contaminated areas. Although truck traffic would be increased during implementation of Alternative 2 the
 implementation period (approximately one month) is short and the number of trucks per day would be'less
 than 20.

 Implementability

 Alternative 2 is considered readily implementable  . Licensed transporters and permitted disposal facilities are
 currently available.
 Cost

 The cost to implement Alternative 2 is estimated at $260,000.
 Regulator Acceptance

 VDEQ and USEPA are currently reviewing this Proposed Plan.  VDEQ  and USEPA comments will  be
 addressed in  the Decision Document.

 Community Acceptance

 Community acceptance  of the preferred alternative will be evaluated at the close of the  public  comment
 period by considering both oral and written comments received during the public comment perioc.


 PREFERRED ALTERNATIVE

Alternative 2, Soil Removal, is recommended by the U.S. Army as the preferred alternative for AREEs 2, 4,
28-5,  and 31. This remedial alternative is a permanent solution that offers long-term effectiveness since the
contaminated soil is removed  to cleanup levels and transported off site for proper disposal.  This  remedial
alternative would be designed to comply with ARARs.  The excavation and disposal of contaminated soil
would be done  in accordance  with federal  and Virginia  solid and hazardous waste  regulations.  The
estimated cost  to  implement this alternative  is  $260,000,  and  the on-site  activities would  require
approximately one month to complete.
                                               17

-------
                 The United States Army
             at Vint Hill Farms Station, Virginia
                  Invites Public
                     Comment
                    ON A PROPOSED
               ENVIRONMENTAL CLEANUP
                 ConcerningFouTAreas'
           Requiring Environmental Evaluation:
                     2,4,28-5, & 31
             Please Come To Our

  *   PUBLIC  MEETING»

      Thursday, April 9,1998 * 7:00 p.m.*
    * Warrenton Middle School Auditorium *
         244 Waterloo Street • Warrenton, VA
       ('Sign Language Interpreter will be present)
PURPOSE: TO DISCUSS AND PRESENT THE REMEDIAL
ALTERNATIVES FOR THE SITES IDENTIFIED ABOVE.

The U.S. Army, inconsullalion wilh the U.S. Environmetllal Pro-
tection Agency (USEPA) Region III and the Virginia Depart-
ment of Environmental Quality (VDEQ), invites public comment
on its Proposed Plan for remediating contaminated soil at the
following Areas Requiring Environmental Evaluation  (AREEs)
on Vint Hill Farms Station (VHFS), Virginia: AREE 2 - Sewage
Treatment Plant; AREE 4 - Auto Craft Shop; AREE 28-5 -
Former Service Station Abandoned Underground Storage Tanks;
and AREE 31 - Construction Debris Pile #1. Before selecting a
final remedy, VHFS will consider all written and oral comments
received during the public comment period.

  The  U.S. Army will be accepting comments during a
      30-day PUBLIC COMMENT PERIOD which
         begins Thursday. March 26.1998
         and ends Friday. April 24.1998.

       WRITTEN COMMENTS MAY BE SUBMITTED
           TO THE FOLLOWING ADDRESS:

         Kevin Bell, Public Affairs Officer
         Public Affairs Office (Bldg. 2500)
*
o
c
to
2»
o'
n& Answer Sessio
3
3J S
CD (D
J2. CD
rT *"*
-i O
3 ~
tizen Members of tr
tion Advisory Boar
0-5
*
< s,
O CD
m 2.
DO
u nt
icialsfromUSEPA,
nd others

m
a
c
o
D)
£?•
onal Presentations

t>
c
CD

O
<
O

m
m
H

1
3J

I
O
z
II
II
••* *-^
o ^_
•3 D)
§3
i* CO
N>55
O Q)
~*. >M.
s=
I
B' =
||
D) -"^
§" J
os:
3.«r
s§
-x ;?
m Q>
§
to
S
vo
           c:
           to
           ti
           o
           to

-------
           ATTACHMENT 2




CLEANUP LEVEL DEVELOPMENT DOCUMENTS

-------

-------
                       HUMAN HEALTH RISK-BASED REMEDIATION GOALS
             AREAS REQUIRING ENVIRONMENTAL EVALUATION (AREEs) 4 AND 31
                               VINT HILL FARMS STATION (VHFS)


Risk-based remediation goals for VHFS based on human exposures at the site were calculated for selected
chemicals detected in surface soil in areas proposed for remediation (i.e., surface soil at AREEs 4 [Auto Craft
Shop] and 31 [Construction Debris Pile #1]).  Based on a review of the exposure pathways evaluated in the
risk assessment, risk-based remediation goals were calculated for chemicals contributing to pathway upper-
bound excess lifetime cancer risks greater than 1x10"* and/or hazard indices (His) greater than or equal to 1.
The development of risk-based remediation goals focused on the incidental ingestion exposure pathway only.
Risk-based remediation goals did not incorporate exposures through the dermal route of exposure due to the
great uncertainties associated with assessing derma! exposures.  For example, major uncertainties exist in
the extent to which chemicals are percutaneously absorbed and in the extent to which chemicals partition
from soil to skin leading to uncertainty in the use of default dermal absorption factors in the evaluation of risk.
Uncertainties also exist in  the use of adjusted oral toxicity criteria to evaluate dermal exposure  pathways
depending on how closely the factors used to adjust oral toxicity criteria reflect the difference between the
oral and dermal routes.

In the VHFS human health risk assessment (HHRA), surface soil incidental ingestion pathways with upper-
bound excess lifetime cancer risks greater than IxlO/4 and/or His greater than or equal to 1 were associated
with adult and child resident exposures at AREE 31. In addition, the U.S. Environmental Protection Agency's -
(USEPA's) residential soil screening level for lead (USEPA, 1994) was exceeded at AREES 4  and 31. The
risk-based remediation goals for selected chemicals in  surface soil were developed based  on  the more
conservative residential receptor, consistent with USEPA Region  III methodology for calculating  risk-based
concentrations (i.e., using combined child/adult residential exposure parameters for carcinogenic compounds
and using child residential exposure parameters for noncarcinogenic compounds).

Risk-based remediation goals were calculated for carcinogenic chemicals associated with chemical-specific
risks greater than or equal to 1x10* and noncarcinogenic chemicals contributing to a HI of 1  for a specific
target organ.   Risk-based remediation  goals  were not calculated for  inorganic  compounds that were
statistically determined to  be within background levels in the risk assessment.  For selected carcinogenic
chemicals, risk-based  remediation goals  were developed using a target risk level of IxlO"6, which is at the
low  end of USEPA's target  risk range  for  health-protectiveness  at  Superfund  sites.   For selected
noncarcinogenic chemicals, risk-based remediation goals were calculated to correspond to a  target hazard
quotient of 1. If any of the noncarcinogenic compounds for which  remediation goals were calculated 'had
similar target organs/critical effects, then the risk-based remediation goal for that noncarcinogenic compound
was divided  by the number of compounds  having the  same target organ/critical effect  (i.e., if three
noncarcinogenic compounds had "liver* as the target organ,  the individual remediation goals would be
divided  by three). For chemicals that exhibit both carcinogenic and noncarcinogenic effects, the selected
remediation goal represents the lower of the two calculated goals.

The following sections present the exposure assumptions and equations used to calculate the risk-based
remediation goals for chemicals in surface soil.  Table 1 presents the toxicity criteria used to calculate the
risk-based remediation goals for chemicals in surface soil.

Surface Soil Risk-Based  Remediation Goals

Risk-based remediation goals were calculated for chemicals in surface soil based on combined child/adult
resident exposures for carcinogens and on child resident exposures for noncarcinogens for the incidental soil
ingestion pathway. The equations and exposure assumptions used to calculate risk-based remediation goals
for surface  soil are  presented below.   Equations  are  presented  separately for chemicals exhibiting
carcinogenic and noncarcinogenic effects.

DACA31-95-D-0083                                  1  '            Human Health Risk-based Remediation Goats
TERC18-10                                                  Areas Requiring Environmental Evaluation 4 and 31
March 6, 1998                                                                      Vint Hill Farms Station

-------
                                                                    TABLE 1
                                                       CHRONIC ORAL TOXICITY CRITERIA
Oral Toxlctty Criteria for Carcinogen!
Weight-of-
Oral Slope Factor Evidence Slope Factor
I (mg/kg-dayr1 Class (a) .Source
Oraf 'ioxlctty Criteria for Noncarclrtogens
Reference Dose
(RfD) Uncertainty Factor Target Organ/
 Chemical
 Organic*
 8enzo(a)anthracane
 Benzo(a)pyrens
 Banzo(b}nuoranlhene
 Benzo(k)fluoranthene
 lndeno{1.2,3-c.d)pyrene

 Inorganic*
 Lead
                                                                                                                                   RID Source
7.3E-01
7.3E-KJO
7.3E-01
7.3E-02
7.3E-01
(d)
(d)
(d)
82
B2
B2
B2
B2
                                                 B2
IRIS
IRIS
IRIS
IRIS
IRIS
                                                             IRIS
                                                                                                                     CNS
                                                                                                                                      IRIS
 (a) USEPA weighi-of-evidence classification scheme for carcinogens:
    A * Human Carcinogen, sufficient evidence of carcJnogenfcfty in humans;
    B1 « Probable Human Carcinogen, limited human data are available:
    82 * Probable Human Carcinogen, sufficient evidence of cmrcinogenicity in animals with inadequate or lack of evidence in humans
    C « Possible Human Carcinogen, limited evidence from animal studies in the absence of human studies- and
    D - Noi classified as to human cananogenicHy, inadequate or-no evidence.
 (B) Unccnamty factors presented are the product* of specific uncertainty factors and modifying factors.  Uncertainty factors used to
   develop reference doses generally consist of multiples of 10. with each factor representing a specific area of uncertainty in the
   data available, The standard uncertainty factors include:
   - a 10-fold factor to account for the variation in sensitivity among the members of the human population;
   - a 10-fold factor to account for the uncertainty in extrapolating animal data to the case of humans;
   - a tO-fold factor to account for the uncertainty in extrapolating from less-than-chronic NOAELs to chronic NOAELs- and
   - a 10-fold factor to account for the uncertainty in extrapolating from LOAELs to NOAELs
   Modifying factors are  applied at the discretion of the RfD reviewer to cover other uncertainties in the data and range from 1 to 10  '
 (  £££!! Of0an "£**?£!?* 5 ^ WBan/etfect mosl """fr*«° «» *•"** «PO«u».  RfDs are based on toxic effects in the
   target organ or cntical effects. If an RfD is based on  a study in which a target organ or critical effect was not identified the
   organ/effect listed is one known to be  affected by the chemical.
 W>,?«?OCef slope^ctor for benzoWpyrene w»« used to evaluate carcinogenic PAHs. along with the toxic equivalency factor
              'U<   ""*  " f°"°WS:  banz(a)anthra°8ne- °'1; benzo{b)fluoranthene. 0.1: benzoMfluoranthene. 0.01;
NOTE
IRIS « Integrated Risk Information System - USEPA,1997a.
— -Ho information available,
CNS * Central Nervous System.
      DACA31-95-D-0083
      TERC18-10
      March 6, 1998
                                                           Human Health Risk-based Remediation Goals
                                                     Areas Requiring Environmental Evaluation t and 31
                                                                                  Vint Hill Farms Station

-------
 The equation used to calculate risk-based remediation goals for chemicals exhibitinq carcinoaenic effort*
 using the combined child/adult exposure parameters based on USEPA (1991), is as foHows  ^
                              C   =    TR * ATe  *  36S days / year
                                     EF * IFA  *  SF0 *  10~6 kg/mg


 where:
 GI   =           chemical concentration in surface soil (mg/kg),
 TR  =           target excess individual lifetime cancer risk (1x10*),
 ATc  =           averaging time for carcinogenic effects (70 years),
 EF  =           exposure frequency (350 days/year),
 |f A  =           adjusted integrated factor (see below) (114.3 rng-year/kg-day), and
 SF°  =           oral cancer slope factor [(mg/kg-day)'1] (see Table 1).
                °hild/adult  resident  exposure parameters  used  to  calculate carcinogenic  risk-based
             goals for incidental  ingestion of surface soil incorporate  an age-adjusted  factor  which
   ™ r      *F Inlegf^ e*P°sure from birt* until age 30 by combining contact rates, body weights, and
 cTjLSd ^fr f°r b°th Ch"dren  and y°ung  adults (USEPA 1997b>-  ™e age-adjusted factor was
 calculated as follows, using exposure parameters from USEPA (1 991 ):
                                     EDc *  IRc  i  rgOtot-gOe; * IR,
                                        BWc            BWa

 where:
 IFA   =        age-adjusted integrated factor (mg-year/kg-day),
 EDc   =        child's exposure duration (6 years),
 IRc    =        child's soil ingestion rate (200 mg/day),
 BWC   =        child's body weight (15 kg),
 ED,,,,   =        total exposure duration (30 years),
 IRi    =        adult's soil ingestion rate (100 mg/day), and
 BW.   =        adult's body weight (70 kg).

 The equation used  to  calculate risk-based remediation  goals for chemicals exhibiting noncarcinogenic
 effects, using the child exposure parameters obtained from  USEPA (1 991 ), is as follows:



                           =       THI * BW * ATne  * 365 days / year
                              EF* ED*  (1/RfDo) *  10-6 kg/mg*  IRSOII
TERC?fl-1n~                                      3              Human Health Risk^jased Remodiation Goals
     R < QQQ                                                Areas R^u'ring Environmental Evaluation 4 and 31
     6,1998                                                                     ^ Hj|| Farms

-------
 where:
 C,    =        chemical concentration in soil (mg/kg),
 THI   =        target hazard index (1),
 BW   =        body weight (15 kg),                         %
 AT^  =        averaging time for noncarcinogenic effects (6 years),
 EF   =        exposure frequency (350 days/year),
 ED   s        exposure duration (6 years),
 RfD0  =        oral chronic reference dose (mg/kg-day) (see Table 1), and
 IRM4  =        soil ingestion rate (200 mg/day).

 Summary of Risk-Based Remediation Goals

 Risk-based remediation goals for AREEs 4 and 31 were calculated  for selected chemicals in surface soil
 Specifically, risk-based remediation goals were calculated for all chemicals associated with chemical-specific
 risks greater than or equal to 1x10* or chemicals contributing  to a HI greater than or equal to 1 for a specific
 target organ for the incidental ingestion  exposure pathway.  Risk-based  remediation goals were not
 calculated for inorganic compounds  that were statistically determined to be within background levels.   Risk-
 based remediation goals for all selected chemicals in surface soil were developed based on conservative
 child/adult resident receptors for carcinogens and child  resident receptors for noncarcinogens.  Risk-based
 remediation goals for surface soil are presented in Table 2.

 Based on a review of the chemicals and pathways evaluated in the risk assessment risk-based remediation
 goals  for surface  soil  were  calculated  for  lead  detected  at  AREE 4;  and benzo(a)anthracene
 benzo(a)pyrene, benzo(b)fiuoranthene, benzo(k)fluoranthene, indeno(1,2,3-c,d)pyrene, and lead detected at
 AREE 31. USEPA's residential soil  screening level for  lead was developed using the Integrated Exposure
 Uptake Biokinetic (IEUBK) model (USEPA,  1994)  and is based  on residential exposures by the  most
 sensitive members of the population (i.e., young children). Since a  risk-based remediation goal cannot be
 calculated for lead due to a lack of available  quantitative carcinogenic and noncarcinogenic toxicity criteria
 the 400 mg/kg residential soil screening level for lead is presented in Table 2 as the remediation goal for lead
 in surface soil,

 References

 U.S. Environmental Protection  Agency (USEPA).  1991.   Risk Assessment Guidance for  Superfund.
      Volume 1:  Human Health Evaluation  Manual Supplemental Guidance.  Standard Default Exposure
      Factors.  Interim Final.  Washington, D.C. OSWER Directive 9285.6-03. March 25,1991.

 U.S. Environmental  Protection Agency (USEPA).  1994. Revised Interim Soil  Lead Guidance for CERCLA
      Sites and RCRA Corrective Action Facilities.  Memorandum to Regional Administrators from Elliot P.
      Laws, Assistant Administrator. Solid Waste and  Emergency Response, OSWER Directive #9355 4-
      12. EPA/540/F-94/043.

 U,S« Environmental  Protection Agency (USEPA).  1997a.  Integrated Resource Information System (IRIS)
      Environmental Criteria and Assessment Office, Cincinnati, Ohio.

 U.S. Environmental Protection Agency (USEPA).  1997b. Risk-Based  Concentration Table  October 22
      1997.
         ~^                                     4             Human Health Risk-based Remediation Goals
                                                          ArBas Requinno Environmental Evaluation 4 and 31
»ju,  c «eoo
March 6. 1898                                                                    Vm{ Hj|| Fam& stfltjon

-------
                                                             TABLE 2
                                   REMEDIATION GOALS FOR CHEMICALS IN SURFACE SOIL (a)
                                        T_oxlcltxjCriterion
  amical
                               Carcinogenic
Noncarcinogenlc
  (mg/kg-day)
                                                                     Carcinogenic (b)
  EE4
  Resident Ingestion
    Lead                            _

  EE31
  Resident Ingestion
    Benzo(a)anthracene             7.3E-01
    Benzo{a)pyrene                 7.3E+00
    Benzo(b)fluoranthene            7.3E-01
    Benzo(k)fluoranthene            7.3E-02
    lndeno(1,2,3-c,d)py'rene          7.3E-01
    Lead                            _
                          0.87
                          0.087
                          0.87
                           8.7
                          0.87
                     Selected Remediation
                             Goal
Noncarcinogenlc (c)       (mg/kg) (d)
                                                                     400 (e)
                             0.87
                             0.087
                             0.87
                              8.7
                             0.87
                            400 (e)
 Remediation goals were calculated for predominant chemicals (i.e., chemicals with risks exceeding 1x10"* or
 chemicals contributing to a HI greater than or equal to 1 for a specific target organ) for the incidental ingestion
 pathways associated with a total excess lifetime cancer risk exceeding 1 x1 V4 or a HI greater than or equal to  1.
 The calculated remediation goals for carcinogenic chemicals were based on a target risk level of IxlO^ and were
  calculated using combined child/adult exposure parameters.
 The calculated remediation goals for noncarcinogenic chemicals were calculated using child resident exposure
  parameters and were based on a hazard quotient of 1.
i The selected remediation goal represents the lower of the calculated carcinogenic and noncarcinogenic
  remediation goals.
) The selected remediation goal is USEPA's residential soil screening level for lead (USEPA, 1994).
      DACA31-95-D-0083
      TERC18-10  '
      March 6,1998
                                 Human .Health Risk-based Remediation Goals
                            Areas Requiring Environmental Evaiuation 4 and 31
                                                      Vint Hill Farms Station

-------

-------
                            ECOLOGICALLY-BASED CLEANUP LEVELS
             AREAS REQUIRING ENVIRONMENTAL EVALUATION (AREEs) 2, 4, AND 31
                                VINT HILL FARMS STATION (VHFS)

        Results of the Ecological Risk Assessment (ERA) conducted as part of the Phase II Reuse Area
 Remedial Investigation (Rl) at VHFS (USAGE, 1998) indicate the potential for adverse effects to ecological
 resources at several on-site locations.  Surface soils at AREEs 2, 4,  and 31 were identified as having the
 greatest potential to adversely affect ecological resources and were selected for remediation  The followinq
 ecological receptors were identified as having the greatest potential to be adversely affected in each of these
        •      AREE 2 (Sewage Treatment Plant)                          •

                       Terrestrial plants from the presence of mercury in surface soil;

                       Earthworms from the presence of mercury in surface soil; and

                       Robins and shrews from the presence of mercury in surface soil.

        •      AREE 4 (Auto Craft Shop)

                       Terrestrial plants from the presence of lead, selenium, and zinc in surface soil; and

                       Robins and shrews from the presence of mercury in surface soil.

        •      AREE 31 (Construction Debris Pile #1)

                       Terrestrial plants from the presence of copper, lead, and selenium in surface soil;

                       Earthworms from the presence of benzo(a)pyrene and copper in surface soil; and

                       Robins and shrews from the presence of mercury in surface soil.

The objective of this document is to identify the reduction in  chemical concentrations necessary to be
protective of these ecological resources.  Because of the conservative nature of the toxicological values and
exposure estimates,  cleanup levels were derived based on an EEQ1 of 10.  The following sections derive
cleanup levels for each of these areas based on the ecological resources at risk.

AREE 2 (Sewage Treatment Plant)

        Terrestrial Plants                                                  '

        Results of the ERA indicate the potential for adverse effects to terrestrial plants from the presence of
mercury in surface soil at AREE 2. A literature-based  toxicity value of 0.3 mg/kg, derived by Will and Suter
(1995a) and used in  the ERA to evaluate the potential for adverse effects to terrestrial plants, was used to
derive the cleanup level for mercury in surface soil.  Using this toxicity value and a target EEQ of 10 the
cleanup level for mercury in surface soil for terrestrial plants at AREE 2 is 3 mg/kg.
   1The Environmental Effects Quotient (EEQ) is the ratio of the estimated exposure concentration/dose for
the chemical of concern and the toxicity reference value (TRV) for the ecological receptor of concern.



DACA31-95-D-0083\         i                      Ecologically-based Cleanup Levels
TERC18-10                                               Areas Requiring Environmental Evaluation 2. 4; and 31
March 6. 1998                                                                     Vint Hill Farms Station

-------
        Egrthworms

        Results of the ERA indicate the potential for adverse effects to earthworms from the presence of
 mercury in surface soil at AREE 2.  A literature-based toxicrty value of 0.1 mg/kg, derived by Will and Suter
 (1995b) and used in the ERA to evaluate the potential for adverse effects to earthworms, was used to derive
 the cleanup level for mercury in  surface soil. Using this toxicity value and a target EEQ of 10, the cleanup
 level for mercury in surface soil for earthworms at AREE 2 is 1 mg/kg.

        Terrestrial Wildlife

        Results of the ERA indicate the potential for adverse effects to robins and shrews from the presence
 of mercury in surface soil at AREE 2. Attachment A outlines the screening model and input parameters used
 in the  ERA to estimate the potential for adverse effects to robins and shrews.  Assumptions in this model
 were designed to provide a highly conservative estimate of the potential for adverse effects to robins and
 shrews.  In the model, it is assumed that robins and shrews would be exposed to the estimated  average
 mercury concentrations detected at AREE 2 (2.79 mg/kg).  However, as discussed in the Rl, samples were
 biased to areas of likely contamination, and samples from these areas  are likely to over-estimate actual
 levels  of contamination throughout the facility.  Further, the highest mercury concentrations were detected
 within  a very localized area of AREE 2. The area of mercury contamination in surface soil at AREE 2 is
 immediately downgradient of the former sludge pile, and is estimated to be approximately 75 feet by 25 feet
 in size. Accordingly, robins and shrews are likely to be exposed to mercury in only a limited proportion of
 their total foraging area and, because of the biased sampling methodology, using an average of the mercury
 concentrations detected in surface soil at AREE 2 will likely over-estimate the potential for exposure and
 adverse effects.

        Cleanup levels were determined by backcalculating through the risk model used in the ERA  Two
 approaches were used to develop cleanup levels for robins and  shrews.  The first approach assumes the
 foraging range of robins and shrews falls entirely in the contaminated areas of AREE 2. This approach is
 consistent  with  that  used  in the ERA and simply requires determining, by  backcalculating through the
 equations presented in Attachment A, an average exposure concentration which is equal  to 10 times the
 toxicity value2 used in the ERA (i.e., an EEQ of 10).  However,  this approach is likely to over-estimate risks
 because it assumes the average AREE 2 exposure concentration, estimated by averaging the concentrations
 of chemical detected at surface  soil sample locations,  is an accurate indicator of chemical concentrations
 throughout the receptor's foraging range. The second approach applies a spatial factor to adjust for the area
 of actual contamination.  This latter approach is expected to provide a more realistic estimate of exposure.

        The spatial factor used for the second approach was derived by first estimating the total area over
 which  a robin  or shrew is likely to forage. Pitts (1984) estimated an average territory size of 0.42 hectares
 (equal  to 45,208 square  feet) for robins on a college campus  in Tennessee.  Meanwhile,  Buckner (1966)
 estimated an average territory size of 0.39 hectares (equal to 41,978 square feet) for shrews.  Cleanup levels
 for AREE 2 were calculated assuming robins and shrews would not be exposed to mercury at any location
 outside of AREE 2. This assumption was made because mercury was not detected  at any other locations
 within the foraging range of these species.

        The total area of potential mercury contamination to which a robin or shrew foraging at AREE 2 could
 be exposed was estimated to be 1,875 square feet by assuming a maximum area of contamination  in  AREE
 2 of 75 feet by 25 feet.  The proportion of the total foraging area at which a robin or shrew associated with
 AREE  2 could be exposed  to mercury was then estimated by dividing the estimated total area contaminated
 with mercury by each species' estimated territory size. Using this approach, a proportion of 0.041 was
2 The toxicity values used in the ERA are based on no observed adverse effects levels (NOAELs) derived by Oak
Ridge National Laboratory (ORNL, 1996).


DACA31-95-D-0083                          ~~     2           '           Ecologically-based Cleanup Levels
TERC18-10                                                Areas ftequiring Environmental Evaluation 2, 4, and 31
March 6.1998                                                                      V,m Hiii Farms Station

-------
 estimated for robin and a proportion of 0.045 was estimated for shrew. This proportion was then used ** *
 multiplier in equations (2) and (5) of Attachment A.                                                as a

         Cleanup levels  derived using the approaches described above are presented in Table  1   The
 approach  which accounts for the limited distribution of mercury in the territorial range of robins and shrew*
 results in  higher cleanup levels.  However, these cleanup levels are expected to be more realistic and are
 .recommended for use as the final cleanup levels. Consistent with the ERA. cleanup levels were also derived
 ?f*£ Jn0rgarl£and °r?anic mercury (metny'mercury). Although it is likely only a proportion of the mercury
 detected m  surface  soil is present in  the organic form, it is recommended that  the  more conservative
 methylmercury cleanup level be selected as the cleanup level for AREE 2.

 AREE 4 (Auto Craft Shop)

        Terrestrial Plants

        Results of the ERA indicate the potential for adverse effects to terrestrial plants from the presence of
 ieag\ selenium,  and zinc in surface soil.  Literature-based toxicity values for lead, selenium, and zinc of 50
 mg/kg, 1 mg/kg, and 50 mg/kg. respectively, derived by Will and  Suter (1995a) were used in the ERA to
 evaluate the potential for adverse effects to terrestrial plants.  Using these toxicity values and a target EEQ of
 10, the cleanup levels for lead, selenium, and zinc in surface soil for terrestrial plants at AREE 4  are 500
 mg/kg, 10  mg/kg, and 500 mg/kg, respectively.

        Terrestrial Wildlife

        Results of the ERA indicate the potential for adverse effects to robins and shrews from the presence
 of mercury in surface soil at AREE 4. Attachment A outlines the screening model and input parameters used
 in the ERA to estimate the potential for adverse effects to robins and shrews. Assumptions in this model
 were designed to provide, a highly conservative estimate of the potential for adverse effects to robins and
 shrews. In the model, it is assumed that robins and shrews would be exposed to the average of the mercury
 concentrations detected at AREE 4 (0.167 mg/kg).  However/as discussed in the Rl, the elevated mercury
 concentrations were detected in very localized areas at AREE 4. The areas of mercury contamination driving
 the nsk to  terrestrial wildlife are comprised of the runoff areas from the storm sewer discharge  the former
 hydraulic lift,  and the wash rack discharge. Each of the areas of mercury contamination are estimated to be
 no greater than  15  feet by 15 feet in size. Accordingly, robins and shrews are likely to  be exposed to this
 chemical in only a very limited proportion of their total foraging area, and the use of an average AREE 4
 mercury concentration will likely over-estimate the potential for exposure and adverse effects to robins and
 shrews.

        Cleanup levels for mercury were calculated for AREE 4 using the same methods described earlier to
 denve cleanup levels for mercury at AREE 2. The contaminated  proportion of the total territory size was
 estimated to  be  0.015 for robins and 0.016 for shrews assuming the contaminated area of AREE 4 is 675
 square feet in size.  Only AREE 4 was factored into the calculation because mercury was not detected at any
 other locations within the foraging range  of these species.  The  cleanup levels derived  for mercury are
 summarized  in Table 1.  It  is recommended that the cleanup level derived using the  approach which
 accounts for the spatial distribution of mercury be used as the cleanup level for AREE 4.  Although it is likely
 only a proportion of the mercury detected  in surface soil is present in the organic form,  it is recommended
 that the more conservative methylmercury cleanup level be selected as the cleanup level for AREE 4
                                                 3                     Ecologically-based Oeanup Levels
.«    
-------
HI
?> oo is
-*i
-------
 AREE 31 (Construction Debris Pile #1)

         Terrestrial Plants
         Results of the ERA indicate the potential for adverse effects to terrestrial plants from the presence of
  ^iSL6  ™    selemum in surface soil. Literature-based toxicfty values for copper, lead, and selenium of
  100 rng/kg 50 mg/kg, and 1 mg/kg. respectively, derived by Will and Suter (1995a) were used in the ERA to
  evaluate he potential for adverse effects to terrestrial plants.  Using these toxicity values and a target EEQ of

   n'nn t±an^neVe'£ f°f 'JET' 'ead' 8nd Selenium in SUrface  soil for terrestrial P|af*s at AREE 31 a°e
  1,000 mg/kg, 500 mg/kg, and 10 mg/kg, respectively.
         Earthworm^

         Results of the ERA indicate the potential for adverse effects to earthworms from the presence of
        ™/£ne H^n00^ in SUrfaCe ?"• Lterature-bas*d toxicity values for benzo(a)pyrene and copper
       a^ w,f   H c"? F;^!^^'  derived by Acha2i et aL (1995' as cited in van Brummelen et al
       and Wll and Suter (1995b) were used in the ERA to evaluate the potential for adverse effects to
 earthworms. Using these toxicity values and a target EEQ of 10, the cleanup levels for benzo(a)pyrene and
 copper in surface -soil for earthworms at AREE 31 are 25.7 mg/kg and 500 mg/kg, respectively.

         Terrestrial Wildlife

         Results of the ERA indicate the potential for adverse effects to robins and shrews from the presence
 of mercury .n surface soil at AREE 31.  Attachment A outlines the screening model and  input parameters
 used in the ERA to estimate the potential for adverse effects to robins  and shrews.  Assumptions in this
 model were designed to provide a highly conservative estimate of the potential for adverse effects to robins
 and shrews. In the model, it is assumed that robins and shrews would  be exposed to the  averaqe of the
 mercury concentrations detected at AREE 31 (0.198 mg/kg).  However, as discussed in the Rl  elevated
 mercury concentrations were detected in a very localized  area of AREE 31.  The area  of mercurv
 contamination in surface soil that is driving the risk to terrestrial wildlife is the northeastern portion of the
 debns pile, which  is estimated to be no greater than 15 feet by 50 feet in size.  Accordingly, robins and
 shrews are likely to be exposed to this chemical in only a very limited proportion of their total foraging area
 and the use of an average AREE 31  mercury concentration will likely overestimate the potential for exposure
 and adverse effects to robins and shrews.

        Cleanup levels for mercury were calculated for AREE 31  using the  methods described earlier to
 derive cleanup levels for mercury at AREEs 2 and 4. The contaminated proportion of the total territory size
 was estimated to be 0.017 for robins and 0.018 for shrews assuming the contaminated area of AREE  31 is
 750 square feet in size.  Only AREE 31 was factored into the calculation because mercury was not detected
 at any other locations within the foraging range of these species. The cleanup levels derived for mercury are
 summarized  in Table 1.  It is  recommended that the cleanup  level derived using the approach which
 accounts for the spatial distribution of mercury be used as the cleanup level for AREE 31  Although it is  likely
 only a proportion of the mercury detected in surface soil is present in the organic form, it  is recommended
 that the more conservative methylmercury cleanup level be selected as the cleanup level for AREE 31.

 Summary of Cleanup Levels

        Table 2 Presents the cleanup levels for chemicals of significant ecological concern in  surface soil for
AREEs 2. 4, and 31. For chemicals that pose potential adverse ecological effects to more than one receptor
the cleanup level  presented  in Table 2 is for the most  sensitive receptor.  It should be  noted that the
recommended cleanup level derived for mercury at AREEs 4 (0.53 mg/kg) and 31 (0.48 mg/kg} are higher
than the maximum detected concentrations  in these AREEs (i.e., 0.393 mg/kg at AREE 4  and 0 208 mg/kg
                                                                       Ecologically-basedCteanupLeve.*
.,  V!?";"                                               Areas Requiring Environmental Evaluation 2. 4, and 31
March 6, 1998                                                                     ^ m Fafms

-------
                                                    Table 2
                                 Cleanup Levels for Chemicals In Surface Soil

AREE2
Mercury
0.192
AREE4
Lead
Mercury
Selenium
Zinc
500
0.534
10
500
AREE 31
Benzo.(a)pyrene
Copper
Lead
Mercury
Selenium
25.7
500
500
0.48
10
DACA31-95-CMW83
TERC18-10
March 6,1998
                Ecologically-based Cleanup Levels
Areas Requiring Environmental Evaluation 2,4, and 31
                          Vint Hill Farms Station

-------
 at AREE 31), indicating that remediation of mercun/ at these AREEs may not be required when its areal
         consiG6r&cf.

 References                                               4

 Achazi, R.K., Chroszcz, G., Duker, C., Henneken, M., Rothe, B., Schaub, K., and Steudel I  1995 The Effect
        of Ruoranthene (Fla), Benzo[a]pyrene (BaP) and Cadmium (Cd) Upon Survival Rate and Life Cycle
        Parameters of Two Terrestrial Annelids in Laboratory Test Systems. Newsl. Enchytraeidae. 4:7-14.

 Buckner,  C.H.   1966.   Populations and Ecological  Relationships  of  Shrews  in Tamarack  Boas of
        Southeastern Manitoba.  J. Mammal. 47:181-194.

 Oak Ridge National Laboratory  (ORNL). 1996. Screening Benchmarks for Ecological Risk Assessment
        Version 1.6. Environmental Sciences and Health Sciences  Research Divisions Oak Ridqe National
        Laboratory. Oak Ridge, TN.

 Pitts, T.D.  1984.  Description of American Robin Territories in Northwest Tennessee. Migrant 55:1-6.

 U.S. Army Corps of Engineers (USAGE).  1998. Remedial Investigation.  Vint Hill Farms Station  Phase II
        Reuse Area Remedial Investigation.  Draft Document  Prepared by ICF Kaiser Engineers Inc
        Edgewood, Maryland. January, 1998.                                                  '    "

 van Brummelen, T.C., van Gestel, CAM., and Verweij. RA  1996.  Long-term Toxicity of Five Polycyclic
        Aromatic Hydrocarbons for the Terrestrial Isopods Oniscus asellus and Porcellio scaber  Environ
        Toxicol. Chem.  15(7):1199-1210.                                                 '

 Will. M.E. and Suter, G.W., II.  1995a. Toxicological Benchmarks  for Screening Potential  Contaminants of
        Concern for Effects on Terrestrial Plants. Rev. ed.  Oak Ridge National Laboratory Oak Ridae TN
        ES/ER/TM-85/R1.                                                                   '

 Will, M.E. and Suter, G.W., II.  1995b. Toxicological Benchmarks  for Screening Potential  Contaminants of
        Concern for Effects on Soil and Litter Invertebrates and Heterotrophic Process  Oak Ridge National
        Laboratory, Oak Ridge, TN.  ES/ER/TM-126.
DACA31-95-D-0083                                 7                      Ecologically-based Cleanup Levels
TCRC18-10                                               Areas Requiring Environmental Evaluation 2,4. and 31
March 6. 1998                                                             .        Vmi H||, Farms station

-------

-------
                                         ATTACHMENT A
                  ESTIMATION OF ROBIN AND SHREW EXPOSURE TO CHEMICALS
                            FOR THE DERIVATION OF CLEANUP LEVELS

         The following sections present the methods used to calculate the potential ingestion of chemicals bv
 robins and shrews from the ingestion of food (i.e., earthworms) and surface soil.  The equations aiven b^iow
 were derived based on equations presented by USEPA (1989).  Table A-i presents specific exposure
 parameter values used in these equations.                                                 c^u^ure

 Total Dose

         The total dietary exposure levels for robins and shrews to chemicals  was determined using the
 following equation:                                                                         y


                                    Dosetotai - Dosewom + Dosesoa
                                                                   (1)

 where:
                =      amount of chemical ingested per day via ingestion of earthworms (in mg/kg b'w-d
                       use equations 2, 3, and 4 to calculate); and
                =      amount of chemical ingested per day from soil (in mg/kg bw-d, use equation  5 to
                       calculate).


 Dose From Earthworms

        The following equation was used to calculate the dose of chemicals that robins and shrews would be
 expected to obtain from the ingestion of earthworms:

                                       DoSSwom = Fl * Cdiet
                                                                   (2)

 where:
 FI              =      food ingestion rate (kg/kg  bw-d); and
 C««    ;        -      estimated chemical concentration in diet (in mg/kg. use equation 3 to calculate).


        The estimated dietary concentration (C^ was calculated using the following equation:


                                             Ctf/e/=Pe*Ce
                                                           (3)

 where:
 P«              =      proportion  of diet consisting of earthworms (unitless); and
 C«              =      estimated  concentration of chemical in earthworms (in  mg/kg, use equation 4 to
                       calculate).
DACA31-95-D-0083                               A-1                     Ecoloflicaily-based Cleanup Levels
          '
     .                                                   Areas Requiring Environmental Evaluation 2. 4, and 31
March 6. 1998                                                                    Vint Hi|, Famis station

-------
                                                     Table A-1
               Summary of Exposure Parameters Used In the Robin and Shrew Food Ingestion Models
    Food ingestion rate (Fl; kg/kg bw-d)
            1.52 (a)
                                                                                                0.62 (g)
    Proportion of diet consisting of earthworms (Pe; unitless)
           0.18(b,c)
         0.314 (h)
   Bioconcentration factor for chemical
   in earthworms (BCF; unitless)
   inorganic mercury = 0.96 (d)
     methylmercury = 27 (e)
inorganic mercury = 0.96 (d)
  methylmercury = 27 (e)
   Soit Ingestion rate (SI; kg/kg bw-d)
  =-.
(a) Hazelton et al. (1984) as cited in USEPA (1993).
(b) Wheelwright (1986) as cited in USEPA (1993).
(c) Howell (1942) as cited in USEPA (1993).
(d) Beyer and Stafford (1993).
(e)Eisler(1987).
(f) Beyer el al. (1994).
(g) Morrison et al. (1957) as cited in USEPA (1993).
(h) Whilaker and Ferraro (1963) as cited in USEPA (1993).
            0.158 (f)
         0.058 (f)
   DACA31-95-D-0083
   TERC18-10
   March 6,1998
A-2                    .    Ecologically-based Cleanup Levels
          Areas Requiring Environmental Evaluation 2,4, and 31
                                     Vint Hill Farms Station

-------
                                                        '> ** fresh ™
                                                                              ^ermined using the
  where:
                                       Ce = Csoil * BCF
                                                            (4)
                        average concentration of chemical detected in surface soil (mg/kq)- and
                        bloconcentration factor for chemical in earthworms (unitless).
  Dose From Soil
                                                         °< *«*"• «- «<*"
                                                                                         would be
                                         Dosesoii = SI *
 where:
 S'
   Mil
                       soil ingestion rate (kg/kg bw-d); and
                       average chemical concentration in surface soil (mg/kg).
 References
                                          f d EVa'Uati°n °f
                                                                        in Earthworms and in Soils
                    ' E"
                                    S' 1994' Estimates of Soi""9estion by Wildlife.  J. Wildl. Manage.
                                                                  A Synoptic Review  Contaminant


Hazelton  P.K., Robel, R.J., and Dayton, A.D.  1984.  Preferences and influences of Paired Food Items on

                                                         and Gray Catbirds V>™*™* oarctinensis).
                                                          R°bin (TurdUS mi9^oriuS). Am. Mild. Nat.
Morrison P.R., Pierce, M., and Ryser, FA. 1957. Food Consumption and Body Weight in the Masked and
        Short-taded Shrews (genus Btarina) in Kansas, .owa, and Missouri.  Ann. cLegie Mus  51 157
                                           . 1989. Risk Assessment Guidance for Superfund. Volume
                 Health Evaluation Manual. Part A. Interim Final.  EPA/540/1-89/002. December, 1989.

U.S. Environmental Protection Agency (USEPA).  1993.  Wildlife Exposure Factors Handbook. Volume I of
       II. Office of Research and Development, Washington, D.C. EPA/630/R-93/187a.
DACA31-95-D-0083
TERC18-10
March 6 1998
                                              A-3
                                              MO
                                                                      g  ,  .
                                                            .          Ecologically-based Cleanup Levels
                                                       Areas Requiring Environmental Evaluation 2, 4, and 31
                                                                               Vint Hill Farms Station

-------
  Wheelwright N.T. 1986. The Diet of American Robins: An Analysis of U.S. Biological Survey Records. Auk

          i UO. / IU"/fcO.




  Whitaker. J.O. and Ferraro. M.G. 1963. Summer Food of 220 Short-tailed Shrews From Ithaca, New York

         J. Mammal. 44:419.
                                                                         Ecologically-based Cleanup Levels

MaVThfi "noon                                               Areas Requiring Environmental Evaluation 2. 4, and 31
March 6. 1998                                                                       Vml m Fafms statjon

-------
ATTACHMENT 3




PUBLIC NOTICE

-------

-------
         The United States Army
   at Vint Hill Farms Station, Virginia

         &.   Invites  Public
         m      Comment
         gy        ON A PROPOSED
         y    ENVIHONMEHTALCLEANUP
                Concerning Four Areas
               Requiring Environmental
               Evaluation: 2,4,28-5, & 31
           Please Come To Our

       .  pllRLIC MEETING  «
 •    Thursday, April 9,1998 • 7:00 p.m.'
  4 Warrenton Middle School Auditorium •
       244 Waterloo Street •  Werrenlon. VA
     (•Sign Language Interpreter will be present)  -

PURPOSE  TO DISCUSS  AND PRESENT THE REME-
DIAL ALTERNATIVES FOR THE SITES IDENTIFIED
ABOVE,

The U S  Army in consultation with the U S Environmen-
tal Protection Agency IUSEPA) Region III and the Virginia
Department ol Environmental Quality IVDEO). nvnes pub-
lic comment on its Proposed Plan for remedietlno. con-
laminated soil al Ihe lolowmg Areas Requiring Environ-
mental Evaluation (AREEs) on Vint Hill Farms Station
IVHFSI Virginia AREE 2- Sewage Treatment Plant: AREE
4 - Auio Craft Shop. AREE 2B-5 - Former Service Station
Abandoned underground Slorage Tanks: and AREE 31 -
Construction Debns Pi* n. Belore selecting  a final rem-
 edy.  VHFS will consider all wnllen  end oral commenls
 received dunng Ine public comment penod.
           KMUCrawlEHTPEHOOwHah
        h..ln. Tlttlf.a.v- M.rch «. MM.          '.
         T~< fin... FHrt.y ApHI 24. 1MB.

   WRITTEN COMMENTS UAY BE SUBMITTED TO THE
             FOLLOWING ADDRESS:              I
        Ktvln Bell. Public AHmln Officer,
        Public Atitln omct IBIdg. 2500)
            l'/nf Htll e*nrtm Star/on.             •
           Wtrremon. VA 10tB7-S001

BACKGROUND

VHFS Is part of Ine U.S Army Communications - Elec-
tronics Command (CECOM) and.  while active, pnmanly
lunctiorwd as an Army Installation anoaged tn communi-
cations Meltigence, VHFS is  located appio.lmalely  40
miles southwest 01 Washmglon. D.C.. in Fauquier County.
Virginia The installalion occupies approximately 701
acres ol land near me town ol warrantor!. Virginia  Ap-
pro.imalely ISO acres  ol me installation are improved
grounds in me soutfiem portion ol the property used lor  i
intlustnet operations, administration buildings, and rest-  j
danttai  housing Approximately 94 acres on Ihe eastern
portion c-l the properly are mature hardwood forest, and
the majonly of the remaning 457 unimproved and semi-
improved acres in Ihe northern ponton of the prooeny  are
used tor stationary and moMe antenna operation sues.
The lacilily was designated lor closure in  March. 1993.
under ihe Base Realignment and Closure (BRACl Act

 PROPOSAL

 VHFS evaluated two remedial alternatives to address sod
 contaminalion al AREEs 2. 4, 2S-S. and 31.

         ALTERNATIVE 1: No Artlon; and
         ALTERNATIVE 2: Soil Removal.

 Based on avadabie information. VHFS prefers Alleme-  i
 live 2 which includes eicavation ol contaminated sort and
 oil-site disposal al a permitted facility. This remedial al-
 ternative is a permanent solution thai otters tong-term
 elltcuveness since me conlamlnated soil Is  removed 10  •
 cleanup levels and iiansported oft site tor proper disposal.
 Since Ihe amount ol soil requiring remedialion is  rela-  |
 lively  small (approumalety 40O cubic yards), it was not  |
 practice! to consider active treat/tier* or containment op-  i
 IKXIS in terms ol cost-ottectrveness and imptemenlaoUity.
 The e«cavat«m and disposal of contamnaltrj soil would
 be done in accordance wim letKral ana Cornmonvreallh
 ol Virginia solid and hazardous  waste regulations

  FOR MOHE fWOnWATOrV
  You can review the Proposed Plan and related lechnical
  documents al Ihe Information Repository  al the knowing
  location:

      Feuouler County Ubmry, Wanemon Branch  •
                 Reference Section
          11 wncheflerSTreer, Warrenton. VA22186
              Uaynr M-w: 10 a.m. -« p m.
       andTh-Sat9a.m..5p.m andSun tp.m.-5pm.
               , Phone (HO) 347-8750
                                                 I

-------

-------
                  Reproduced by NTIS
 »-  )I 0) O
 0  £ O 0)
 .   (0 mM-
±000)
*- a —
 00??
j_i ••  •
± 0) 0 C
EE.-0
t 
0£.So
        "
         «
   1-8 E
   Sgra
   uETJ
                   National Technical Information Service
                   Springfield, VA 22161
        This report was printed specifically for your order
      from nearly 3 million titles available in our collection.
For economy and efficiency, NTIS does not maintain stock of its vast
collection of technical reports. Rather, most documents are printed for
each order. Documents that are not in electronic format are reproduced
from master archival copies and are the best possible reproductions
available.  If you have any questions concerning this document or any
order you have placed with NTIS, please call our Customer Service
Department at (703) 605-6050.

About NTIS
NTIS collects scientific, technical, engineering, and business related
information — then organizes, maintains, and disseminates that
information in a variety of formats — from microfiche to online services.
The NTIS collection of nearly 3 million titles includes reports describing
research conducted or sponsored by federal agencies and their
contractors; statistical and business information; U.S. military
publications; multimedia/training products; computer software and
electronic databases developed by federal agencies; training tools; and
technical reports prepared by research organizations worldwide.
Approximately 100,000 new titles are added and indexed into the NTIS
collection annually.
    For more information about NTIS products and services, call NTIS
    at 1-800-553-NT1S (6847) or (703) 605-6000 and request the free
     NTIS Products Catalog, PR-827LPG, or visit the NTIS Web site
                      http://www.ntis.gov.
                            NTIS
      Your indispensable resource for government-sponsored
                information—U.S. and worldwide

-------

-------