Superfund Record of Decision Naval Weapons Station-yorktown Site 12 OU's 3 4 and 5 Yorktown PA


                                    EPA/ROD/R03-97/181
                                    1997
EPA Superfund
     Record of Decision:
     NAVAL WEAPONS STATION - YORKTOWN
     EPA ID: VA8170024170
     OU04
     YORKTOWN, VA
     04/16/1997

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                                         FINAL
                                    RECORD  OF DECISION
                                         SITE  12
                                 BARRACKS  ROAD LANDFILL
                            (OPERABLE UNIT  NOs. Ill,  IV,  AND V)
                              NAVAL WEAPONS  STATION YORKTOWN
                                    YORKTOWN,  VIRGINIA
                                          MAY 1997

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                    TABLE OF CONTENTS
                                                                                        Page

LIST OF ACRONYMS AND ABBREVIATIONS	vii

DECLARATION FOR THE RECORD OF DECISION REMEDIAL ALTERNATIVE
SELECTION	ix
     Site Name and Location	ix
     Statement of Basis and Purpose	ix
     Assessment of the Site	ix
     Description of the Selected Remedy	ix
     Statutory Determinations	ix

DECISION SUMMARY	1-1

1.0  INTRODUCTION	1-1

2.0  SITE NAME, LOCATION, AND DESCRIPTION	2-1
     2.1  Site Description	2-1
     2.2  Operable Units	2-5

3.0  SITE HISTORY AND PREVIOUS INVESTIGATIONS/ENFORCEMENT
     ACTIVITIES	3-1
          Site History	3-1
          Previous Investigations	3-1
          3.2.1   Initial Assessment Study	3-1
          3.2.2   Confirmation Study	3-2
          3.2.3   Round One RI	3-2
          3.2.4   Habitat Evaluation	3-4
          3.2.5   Background Constituent Study	3-4
          3.2.6   Round Two RI	3-4
          3.2.7   Feasibility Study	3-13

4.0  HIGHLIGHTS OF COMMUNITY PARTICIPATION	4-1

5.0  SCOPE AND ROLE OF THE RESPONSE ACTION	5-1

6.0  SUMMARY OF SITE CHARACTERISTICS	6-1
     6.1  Surface Soil	6-1
     6.2  Subsurface Soil	6-1
     6.3  Groundwater	6-6
     6.4  Surface Water	6-10
     6.5  Sediment	6-12

7.0  SUMMARY OF SITE RISKS	7-1
     7.1  Human Health Risk Assessment	7-1
          7.1.1   Current Potential Receptors	7-1
          7.1.2   Future Potential Receptors	7-2
     7.2  Ecological Risk Assessment	7-14
          7.2.1   Aguatic Ecosystem	7-14
          7.2.2   Terrestrial Ecosystem	7-18
     7.3  Conclusions of the Baseline RA	7-22

8.0  DESCRIPTION OF ALTERNATIVES	8-1
     8.1  Soil RAA 1:  No Action	8-2
     8.2  Soil RAA. 2:  Institutional Controls,  Monitoring, and Erosion Control	8-2
     8.3  Soil RAA. 3:  Soil/Clay (or clay eguivalent) Cover	8-3
     8.4  Soil RAA 4:  Excavation and Off-Site Landfill Disposal	8-3
     8.5  Soil RAA 5:  In Situ Solidification/Stabilization	8-5
     8.6  Soil RAA 6:  Excavation and Soil Washing	8-5

9.0  SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES	9-1
     9.1  Overall Protection of Human Health and the Environment	9-1

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     9.2  Compliance with ARARs	9-6
     9.3  Long-Term Effectiveness and Permanence	9-6
     9.4  Reduction of Toxicity,  Mobility, or Volume Through Treatment	9-7
     9.5  Short-Term Effectiveness	9-7
     9.6  Implementability	9-7
     9.7  Cost	9-8
     9.8  Commonwealth Acceptance	9-8
     9.9  Community Acceptance	9-9

10.0 THE SELECTED REMEDY	10-1
     10.1 Remedy Description 	 10-1
          10.1.1  The Selection of Soil RAA. 3:   (or clay equivalent) Cover for OU III  10-2
          10.1.2  The Selection of the No Action Alternative for OU IV	10-3
          10.1.3  The Selection of Institutional Controls and a Long-Term
                  Groundwater,  Surface Water, and Sediment Monitoring Program
                  for OU V	10-3
     10.2 Performance Standards	10-4
          10.2.1  Soil/Clay  (or clay equivalent) Cover and Erosion Control Measures    10-4
          10.2.2  Long-Term Monitoring 	 10-5
     10.3 Estimated Costs	10-8

11.0 STATUTORY DETERMINATIONS	11-1
     11.1 Protection of Human Health and the Environment 	 11-1
     11.2 Compliance with Applicable or Relevant and Appropriate Requirements
          (ARARs)	11-1
     11.3 Cost-Effectiveness 	 11-2
     11.4  Utilization of Permanent Solutions and Alternative Treatment
           Technologies	11-2
     11.5  Preference for Treatment as a Principal Element 	 11-7

RESPONSIVENESS SUMMARY 	 RS-1

APPENDICES

A    Extent of Groundwater Contamination - Figures A.1 through A.8
B    Remedial Action Alternatives for Groundwater
C    Public Meeting Minutes
                    LIST OF TABLES
3-1  Chemicals of Potential Concern  (COPCs) Per Media - Site 12	3-8
3-2  Ecological Contaminants of Concern  (ECOCs) Per Media - Site 12	3-11

5-1  Chemicals of Concern Site 12 - Area A Surface Soils	5-2

6-1  Site 12 - Area A - Surface Soil COPC Summary	6-2
6-2  Site 12 - Area B/C - Surface Soil COPC Summary	6-4
6-3  Site 12 - Wood/Debris Disposal Area - Surface Soil COPC Summary	6-5
6-4  Site 12 - Area A - Shallow Subsurface Soil COPC Summary	6-7
6-5  Site 12 - Proper - Subsurface Soil COPC Summary	6-8
6-6  General Background Groundwater Quality of the Cornwallis Cave Aquifer
     and the Underlying Yorktown-Eastover Aquifer	6-10
6-7  Comparison of Select Sediment ECOCs to ER-L/ER-M Values	6-14

7-1  Total Site Incremental Cancer Risk  (ICR)  and Hazard Index (HI) Values for
     Potential Current Receptors - Site 12	7-3
7-2  Site 12 - Area A, Incremental Cancer Risk (ICR)  and Hazard Index  (HI) Values
     for Future Adult and Child On-Site Residents	7-5
7-3  Site 12 - Area B/C, Incremental Cancer Risk (ICR)  and Hazard Index  (HI) Values
     for Future Adult and Child On-Site Residents	7-8
7-4  Site 12 - Wood/Debris Disposal Area Incremental Cancer Risk (ICR)  and Hazard

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     Index (HI)  Values for Future Adult and Child On-Site Residents	7-11
7-5  Frequency and Range of Detection of Selected Surface Water ECOCs Compared
     to USEPA Region III Freshwater Screening Levels	7-15
7-6  Summary of Chronic Daily Intake Models for Terrestrial Receptors Exposed to
     Site 12 Soils and Ballard Creek Surface Waters	7-20

9-1  Glossary of Evaluation Criteria 	  9-2
9-2  Summary of the Soil RAA Evaluation	9-3

10-1 Area A Soil Remediation Levels	10-6
10-2 Long-Term Monitoring Trigger Values	10-7

11-1 Location-Specific ARARs and TBCs	11-3
11-2 Potential Action-Specific ARARs and TBCs	11-5

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                    LIST OF FIGURES

2-1  Location of Naval Weapons Station Yorktown,  Virginia	2-2
2-2  Site Map	2-3

3-1  Round One RI Sampling Locations	3-3
3-2  Round Two RI Soil Sampling Locations	3-5
3-3  Round Two RI Subsurface Soil,  Hydropunch/Temporary Piezometer,
     and Monitoring Well Sampling Locations	3-6
3-4  Round Two RI Surface Water/Sediment Sampling Locations	3-7

5-1  Lead Contaminated Soil Area of Concern,  Site 12- Area A	5-3

6-1  TCE Concentrations Detected in Surface Water	6-11
6-2  Detections of COCs in Sediment (0-4")  and Subsurface Sediment (4-8")
     Exceeding ER-M Values	6-13

7-1  Round Two Statistical Summary of Benthic Macroinvertebrates	7-17
7-2  Round Two RI Sediment Grain Size Classification	7-19

8-1  Soil RAA 3:  Soil/Clay (or clay eguivalent)  Cover	8-4

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               LIST OF ACRONYMS AND ABBREVIATIONS
AOC
ARAR

Baker
bgs

CERCLA
CFR
COG
COPC
CSF

DDD
DoN

ECOC
ER-M
ER-L

FFA
FS

GW

HI
HQ

IAS
ICR
IR
Area of Concern
applicable or relevant and appropriate requirement

Baker Environmental, Inc.
below ground surface

Comprehensive Environmental Response, Compensation and Liability Act
code of Federal Regulations
chemical of concern
contaminant of potential concern
cancer slope factor

Di chlorodiphenyldichloroethane
Department of the Navy

ecological contaminant of concern
Effects Range-Median
Effects Range-Low

Federal Facility Agreement
Feasibility Study

groundwater

hazard index
hazard quotient

Initial Assessment Study
incremental cancer risk
Installation Restoration
MB I
mg/Kg
Ig/Kg
Ig/dl
Ig/L

NCP
NOAA
NPW

O&M
OU

PAH
PCB
PRAP

QI

RA
RAA
RCRA
RDX
RfD
RI
RL
ROD
RGO
macroinvertebrate biotic index
milligrams per kilogram
micrograms per kilogram
micrograms per deciliter
micrograms per liter

National Oil and Hazardous Substances Pollution Contingency Plan
National Oceanic and Atmospheric Administration
net present worth

operation and maintenance
Operable Unit

polynuclear aromatic hydrocarbon
polychlorinated biphenyl
Proposed Remedial Action Plan

quotient index

risk assessment
remedial action alternative
Resource Conservation and Recovery Act
hexahydro-1,3,5-trinitro-l,3,5-triazine
reference dose
Remedial Investigation
remediation level
Record of Decision
Remediation Goal Objective

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               S               soil
               SARA            Superfund Amendments and Reauthorization Act
               SB              soil boring
               SD              sediment
               SSA             Site Screening Area
               SVOC            semivolatile organic compound
               SW              surface water
               SWSL            surface water screening level

               TAL             target analyte list
               TBC             to-be-considered criterion
               TCE             trichloroethene
               TDI             total daily intake
               TNB             trinitrobenzene
               TNT             2,4,6-trinitrotoluene
               TRV             toxicity reference value
               TSCA            Toxic Substance Control Act

               UBK             uptake biokinetic
               USEPA           United States Environmental Protection Agency
               UST             underground storage tank

               VADEQ           Virginia Department of Environmental Quality
               VDHR            Virginia Department of Historic Resources
               VOC             volatile organic compound

               WPNSTA Yorktown      Naval Weapons Station Yorktown

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DECISION SUMMARY

1.0 INTRODUCTION

This Record of Decision (ROD) document presents the final remedial action selected for Site 12, the Barracks
Road Landfill (Operable Unit [OU] Nos. Ill, IV, and V), at Naval Weapons Station Yorktown (WPNSTA Yorktown),
Yorktown, Virginia. The environmental media at this site were investigated as part of a Remedial
Investigation (RI), and remedial action alternatives (RAAs) were developed and evaluated as part of a
Feasibility Study (FS). Based on the results of the RI and FS, preferred RAAs were identified in a Proposed
Remedial Action Plan (PRAP) document. Then, the public was given the opportunity to comment on the RI, FS,
and PRAP. Based on comments received during the public comment period, and any new information that became
available in the interim, a final remedial action plan was selected for Site 12. This ROD document presents
the final selected remedy along with a summary of the remedy selection process.

The Decision Summary of the ROD is organized into 11 main sections. Section 1.0 presents an introduction,
and Section 2.0 presents the site name and location, and a brief description of the site layout. Section 3.0
presents a history of the site and previous investigations/enforcement activities conducted there. Section
4.0 highlights community participation events that have occurred during the development of this ROD. Section
5.0 describes the scope and role of the response action developed to address the site contamination, and
Section 6.0 summarizes the nature and extent of this site contamination (i.e., the site characteristics).
Section 7.0 summarizes the site risks as determined by human health and ecological risk assessments. Section
8.0 describes the RAAs developed for soil and groundwater, while Section 9.0 summarizes the comparative
analysis of these alternatives. Finally, Section 10.0 presents the final remedy selected for Site 12, and
Section 11.0 evaluates the selected remedy with respect to the statutory determinations.

2.0 SITE NAME, LOCATION, AND DESCRIPTION

2 .1 Site Description

The Site 12 study area contains Site 12 proper and the surrounding study area which are located in the
eastern portion of WPNSTA Yorktown (also referred to as the Station). The Station is a 10,624-acre
installation located on the Virginia peninsula in York County, James City County, and the City of Newport
News (Figure 2-1). Site 12 is one of several sites and site screening areas (SSAs)located within the Station
The Site 12 study area encompasses 92 acres and is located near the Industrial Area of WPNSTA Yorktown
(Figure 2-2). In general, the study area is bordered by Barracks Road to the west, and Ballard Creek and the
Colonial National Historical Park to the east and south.

Site 12 proper contains three former disposal areas. One of the former disposal areas, designated as Area A,
is located north of SSA 15 and northeast of the Industrial Area Building 4. Area A is partially wooded and
covers approximately 4.4 acres. An incinerator building and a smoke stack are located within Area A. The
incinerator building contains two incinerators which were formerly used to burn industrial and nonindustrial
wastes. The ash from the incinerators was disposed in a topographic low area or ditch that leads to Ballard
Creek and is located immediately southwest of the incinerator building. A stream channel flows through this
ditch and into Ballard Creek. Another former disposal area, designated as Area B/C, is located east of
Barracks Road and adjacent to the access road leading to the incinerator building. Area B/C covers
approximately 1.6 acres. A portion of Area B/C is an open field. Other portions are wooded and contain
steep slopes and ravines. The third former disposal area has been designated the Wood/Debris Disposal Area.
this area is located east of Areas A and B/C and covers approximately 3.3 acres. The Wood/Debris Disposal
Area was created when wood and miscellaneous construction debris were disposed of and pushed into a ravine
toward Ballard Creek. The disposed material was then covered with soil. The Wood/Debris Disposal Area is an
open field with visible debris protruding out along the backside of this area adjacent to Ballard Creek. A
ditch with an intermittent stream channel is located adjacent to the

Wood/Debris Disposal Area.

As shown in Figure 2-2, SSA 15, the Abandoned Sewage Disposal Plant No. 1, is located within the expanded
Site 12 study area. However, based on the Round Two RI results and investigations specific to SSA 15, this
SSA does not appear to be a source of contamination to environmental media. As a result, no additional
investigative efforts are proposed for SSA 15 (as well as Areas of Concern [AOCs] 5, 6, and 7) under the
Installation Restoration (IR) Program.

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Review of historical aerial photographs revealed the presence of a former railroad spur that cut across Site
12 proper. The spur was connected to the existing railroad track in the Industrial Area, near Buildings 4
and 5. It appears as though the spur crossed Barracks Road and terminated in the general vicinity of the
incinerator building at Area A. Information regarding the spur and when it was removed is not available.
However, the historical aerial photographs indicate that the majority of the spur had been removed prior to
October 1986.

The overall topography of the Site 12 study area is varied, but it generally slopes to the south-southeast
from Barracks Road toward Ballard Creek. Relatively level, grass covered fields comprise portions of the
northwestern guarter of Area A, the area northwest of the incinerator building (between Areas A and B/C),
part of the Wood/Debris Disposal Area and a small area around SSA 15. The remainder of the Site 12 study
area is predominantly wooded. The overall topography ranges from gently rolling to steep ravines.

As shown in Figure 2-2, several stream channels drain Site 12. The northernmost stream channel is located in
the ditch adjacent to the northeast boundary of the Wood/Debris Disposal Area; another channel is located
within the ditch bisecting Area A; while two additional channels converge and form one channel southwest of
SSA 15. All of these channels drain into Ballard Creek which
defines the southern boundary of the Site 12 study area and directs surface water northeast to the
York River.

With respect to local hydrology, Site 12 is located downgradient of the Industrial Area (Buildings 3 through
6). Industrial Area operations have had an impact on the shallow groundwater that flows from the Industrial
Area toward Site 12 and ultimately to Ballard Creek. Underground storage tanks (USTs) that formerly
contained waste oil, solvents, and/or heating oil have been associated with Buildings 3 through 6. The
integrity of these tanks may have been compromised. One of these tanks, UST 5.1, was located adjacent to the
northern corner of Building 5, upgradient from Site 12. The UST was an asphalt-coated steel tank with a
capacity of approximately 12,400 gallons. The tank had been used originally to store fuel oil; however, was
later used to store waste oil. In December of 1993, the tank was closed and removed. Other USTs similar to
UST 5.1 were present between Buildings 3 and 4. One of the USTs was removed in 1993, and another one remains
in use supplying Number 5 fuel oil to the boiler in Building 3. The active UST has recently passed tightness
testing and is not likely a source of contamination to the shallow groundwater.

2.2 Operable Units

A Comprehensive Environmental Response Compensation and Liability Act (CERCLA) remedial action is often
divided into operable units or OUs. As defined in the National Oil and Hazardous Substances Pollution
Contingency Plan (NCP)(40 Code of Federal Regulations [CFR] 300.5), "an Operable Unit means a discrete action
that comprises an incremental step toward comprehensively addressing site problems. This discrete portion of
a remedial response manages migration or eliminates or mitigates a release, threat of release, or pathway of
exposure. The cleanup of a site can be divided into a number of operable units, depending on the complexity
of the problems associated with the site. Operable units may address geographical portions of a site,
specific site problems or initial phases of an action, or may consist of any set of actions performed over
time or any actions that are concurrent but located in different parts of the site."

Site 12 was divided into three operable units: OU III which corresponds to soil at Area A of Site 12;
OU IV which corresponds to soils at Areas B/C and the Wood/Debris Disposal Area; and OU V which corresponds
to groundwater across the study area, and surface water and sediment in Ballard Creek. Groundwater, surface
water, and sediment were combined into the same operable unit because shallow groundwater from Site 12
potentially recharges Ballard Creek. Thus, groundwater, surface water, and sediment are interrelated.

3.0 SITE HISTORY AND PREVIOUS INVESTIGATIONS/ENFORCEMENT ACTIVITIES

3.1 Site History

The former disposal areas at Site 12 were in operation from approximately 1925 to the mid-1960s. During this
time, the disposal areas received an estimated 1,400 tons of waste. Wastes reported to have been disposed at
the three disposal areas include refuse, scrap wood, piping, steel containers, and nitramine-contaminated
packaging. It is likely that solvents were also disposed.

With respect to Area A, wastes were transported to the site by truck and railcar and open-burned prior to
disposal. In addition, the two incinerators located at Area A were used to burn a variety of waste taken
from ships coming from foreign ports. Ash from incineration activities was disposed on the hillside behind
the incinerator building. The hillside trends toward the ditch which bisects Area A. Ash from wastes that

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were open-burned in the northern section of Area A were spread across the top of Area A toward the
incinerator to the south. Scrap metal, charred wood and cloth, and glass have been observed in the ash.

The Wood/Debris Disposal Area was reportedly used for disposal of lumber (not matching specifications),
wooden pallets and miscellaneous construction debris which are still presently visible on the backside of the
area in the vicinity of Ballard Creek.

3.2 Previous Investigations

Previous investigations conducted at Site 12 include an Initial Assessment Study (IAS), two Confirmation
Studies, a Focused Biological Sampling and Preliminary Risk Evaluation, a Round One RI, a Habitat Evaluation,
a Background Constituent Study, a Round Two RI, and an FS. The following provides a brief description of
these investigations.

3.2.1 Initial Assessment Study

An IAS was conducted at WPNSTA Yorktown in 1984. The purpose of the IAS was to identify and assess sites
posing a potential threat to human health and/or the environment due to contamination from past operations.
The study identified 15 sites at WPNSTA Yorktown, including Site 12, that were of sufficient potential threat
to human health or the environment to warrant further investigations.

3.2.2 Confirmation Study

In 1986 and 1988, two rounds of sampling were conducted for a Confirmation Study at Site 12. The study was
documented in two Confirmation Study reports and a third report titled the RI Interim Report. The results of
this study recommended that further RI activities be conducted at Site 12.

3.2.3 Round One RI

The Round One RI for Site 12 was conducted in 1992. The field investigation included the collection of
surface soil, subsurface soil, groundwater, surface water, and sediment samples at the locations identified
in Figure 3-1. Contaminants were detected in all media sampled at the site. Several inorganic compounds
(e.g., lead, cadmium, mercury, zinc) were detected in soil samples at concentrations exceeding site-specific
background levels. Volatile organic compounds (VOCs) (e.g., trichloroethene [TCE]), and nitramine compounds
(e.g., 2,4,6-trinitrotoluene [TNT]; 1,3,5-trinitrobenzene [1,3,5-trinitrobenzene [1,3,5-TNB]; and
hexahydro-1,3,5-trinitro-l,3,5-triazine [RDX]) were detected in the groundwater samples. With respect to
surface water samples, concentrations of several inorganic compounds (e.g., copper, mercury, and nickel) were
detected above surface water criteria in filtered samples. Sediment samples contained levels of certain
pesticides, polychlorinated biphenyls (PCBs), and inorganic compounds which exceeded the National Oceanic and
Atmospheric Administration (NOAA) sediment guality values. In addition, several inorganic compounds,
including beryllium, barium, cadmium, lead, manganese, mercury, silver, and zinc were detected in the
sediment samples at concentrations exceeding site-specific background concentrations As a result of the Round
One RI field investigation, the Wood/Debris Disposal Area was identified as a potential area of
contamination. In addition, the Round One RI identified data gaps with respect to potential impacts to
ecological receptors, and to the nature and extent of the contamination at
Site 12. Therefore, the Round One RI recommended additional sampling for all environmental media at
Site 12.

3.2.4 Habitat Evaluation

A habitat evaluation was conducted in 1994 to address the aguatic habitats (stream areas) and the terrestrial
habitats (land areas) at Site 12. With respect to the aguatic habitats, the study noted that
Site 12 is located within the Ballard Creek watershed which is a freshwater tributary to the York River. In
addition, wetlands were identified south of the incinerator building at Area A and along Ballard Creek north,
east, and south of the site. Three types of general terrestrial habitats were identified including open
fields, mature upland forest, and scrub-shrub/mixed deciduous forest edge with colonizing trees. A variety
of birds, turtle eggs, and signs of deer, sguirrels and groundhogs were observed.

3.2.5 Background Constituent Study

A Background Constituent Study was conducted for WPNSTA Yorktown in 1995. The main objective of this study

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was to provide detailed information on soil, groundwater, surface water, sediment, and biologic communities
at areas within or near WPNSTA Yorktown that had potentially been affected by Station activities.  The study
is documented in a report titled, Summary of Background Constituent Concentrations and Characterization of
Biotic Community from the York River Drainage Basin.  The information obtained during the Background Study
can be used to distinguish between site related and naturally occurring constituent concentrations.

3.2.6     Round Two RI

Conducted in 1994, the Round Two RI field activities included surface soil, subsurface soil, groundwater,
surface water, sediment and biota sampling at the locations identified in Figures 3-2, 3-3, and 3-4.
Analytical results of these sampling efforts are summarized later in Section 6.0  (Site Characteristics) of
this ROD.  During the Round Two RI, human health contaminants of potential concern (COPCs) and ecological
contaminants of concern (ECOCs) were identified. Tables 3-1 and 3-2 present COPCs and ECOCs identified for
Site 12.  Baseline risk assessments (RAs)  were conducted to evaluate the potential risks associated with
these COPCs and ECOCs.  The results of the RAs are summarized later in Section 7.0 of this ROD.

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                                                                            TABLE  3-1

                                                        CHEMICALS  OF  POTENTIAL  CONCERN (COPCs)  PER MEDIA
                                                                              SITE 12
                                                                   NAVAL WEAPONS STATION YORKTOWN
                                                                       YORKTOWN,  VIRGINIA
COPCs

Volatiles:

1,1-Dichloroethane
1,2-Dichloroethane
1,1-Dichloroethene
cis-1,2-Dichloroethene
1,1,1-Trichloroethane
Trichloroethene
Vinyl Chloride

Semivolatiles:
                          Surface Soils
Surface      Surface      Wood/Debris     Shallow
 Soils      Soils Area     Disposal     Subsurface
Area A         B/C           Area          Soil
                        Shallow
                        Ground-
                        water
                        (total)
                                                         X
                                                         X
                                                         X
                                                         X
                      Shallow     Deep
                      Ground-    Ground-
                      water      water
                     (dissolved)   (total)
   Deep
  Ground-
   water
(dissolved)
                                      X
                                      X
                                      X
                                      X
Surface
 Water
(total)
                                                             X

                                                             X

                                                            X
                                                            X
  Surface
  Water
(dissolved)
                               X

                               X

                               X
                               X
                                                                                                                                                         Sediment
Benzo(a)anthracene         X
Benzo(a)pyrene             X
Benzo(b)fluoranthene       X
Benzo(k)fluoranthene       X
Chrysene                   X
Dibenzo(a,h)anthracene     X
Indeno(1,2,3-cd)pyrene     X
Phenanthrene
Pyrene
                X
                X
                X
                X
                X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
                                            X
                                            X
                                            X
                                            X
                                            X
                                            X
                                            X
                                            X
                                            X

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                                                                     TABLE 3-1  (Continued)
          COPCs
Pesticides/PCBs:
4,4'-DDE
Heptachlor Epoxide
Aroclor-1242
Aroclor-1248
Aroclor-1254
Aroclor-1260
Nitramines:
Nitrobenzene
RDX
1,3,5-Trinitrobenzene
2,4,6-Trinitrotoluene
Inorganics:
Aluminum
Antimony
Arsenic
Barium
Beryllium
Cadmium
Chromium
Copper
                         Surface
                          Soils
                         Area A
X
X

X
X
X
X
X
X
X
X
                                                      CHEMICALS OF POTENTIAL CONCERN  (COPCs) PER MEDIA
                                                                                SITE 12
                                                               NAVAL WEAPONS STATION YORKTOWN
                                                                      YORKTOWN, VIRGINIA
          Surface
         Soils Area
            B/C
Surface Soil
Wood/Debris
  Disposal
    Area
       X

       X

       X
 Shallow
Subsurface
   Soil
      X
      X
      X
      X
      X
      X
      X
      X
Shallow
Ground-
 Water
(total)
                                                      X
                                                      X
    X
    X
    X
    X
    X
  Shallow
  Ground-
  Water
(dissolved)
 Deep      Deep
 Ground-   Ground-    Surface
 Water     Water     Water
(total)(dissolved)  (total)
  Surface
  Water
(dissolved)
                                           X
                                           X
     X
     X
Sediment

     X

     X

     X
     X
                                                    X
                                                    X
                                                    X

                                                    X
                                                    X
                                                    X

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               TABLE 3-1  (Continued)


COPCs
Inorganics (Continued) :
Cyanide (total)
Lead
Manganese
Mercury
Nickel
Silver
Thalliuim
Vanadium
Zinc
Surface
Soils
Area A


X
X
X
X

X
X
X
CHEMICALS OF POTENTIAL CONCERN  (COPCs) PER MEDIA
                          SITE  12
         NAVAL WEAPONS STATION YORKTOWN
                YORKTOWN, VIRGINIA
Surface
Soils
Area A
Surface
Soils Area
B/C
Surface Soil
Wood/Debris
Disposal
Area
Shallow
Subsurface
Soil
Shallow
Ground-
Water
(total)
Shallow
Ground-
Water
(dissolved)
                 X
                 X
                 X
                 X
X
X
                            X
                            X
                                                  Deep      Deep
                                                  Ground-   Ground-   Surface     Surface
                                                  Water    Water     Water       Water
                                                 (total)(dissolved)  (total)     (dissolved)
                                                                        X
                                                                   Sediment
                                                                                                    X
                                                                                                    X
                                                                        X
                                                                        X

-------
                                     TABLE 3-2

                ECOLOGICAL CONTAMINANTS OF CONCERN  (ECOCs) PER MEDIA
                                      SITE 12
                           NAVAL WEAPONS STATION YORKTOWN
                                 YORKTOWN,VIRGINIA
         Contaminant
Volatiles:
Surface
 Water  Sediment
                      Area A
                                                            Surface Soil
          Area B/C
Wood
   Debris/Disposal
         Area
2-Butanone
Semivolatiles:
Acenaphthene
Acenaphthylene
Anthracene
Benzo(a)anthracene
Benzo(b)fluoranthene
Benzo(k)fluoranthene
Benzo(g,h,i)perylene
Benzo(a)pyrene
Carbazole
Chrysene
Dibenz(a,h)anthracene
Dibenzofuran
1,4-Dichlorobenzene
Fluoranthene
Fluorene
Indeno(1,2,3-cd))pyrene
Naphthalene
Phenanthrene
Pyrene
Pesticides/PCBs:
           x
           x

           x
           x
           x
           x
           x
           x
           x
           x
           x
           x
           x
           x
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X


X
X
X
X
X
X
X

X
X

X

X
                                X
                                X
                                X
                                X
                                X


                                X

                                X
                                X
                                X


                                X
                                X
                                X


                                X
                                X
4,4'-ODD
4,4' -DDE
alpha-Chlordane
gamma-Chlordane
Endosulfan I
Endrin Aldehyde
Aroclor - 1242
Aroclor - 1248
Aroclor - 1254
Aroclor - 1260
           x
           x
           x
           x
           x
           x
           x

           x
           x
x
x
x

-------
                                     TABLE 3-2(Continued)

                ECOLOGICAL CONTAMINANTS OF CONCERN  (ECOCs) PER MEDIA
                                      SITE 12
                           NAVAL WEAPONS STATION YORKTOWN
                                 YORKTOWN,VIRGINIA
         Contaminant
Nitramines:
Surface
 Water  Sediment
                                                            Surface Soil
                                                                            Wood
Area A       Area B/C
Debris/Disposal
      Area
2,4-Dinitrotoluene
1,3,5-Trinitrobenzene
Inorganics:

Aluminum
Antimony
Arsenic
Barium
Beryllium
Cadmium
Chromium
Cobalt
Copper
Cyanide, total
Iron
Lead
Manganese
Mercury
Nickel
Selenium
Silver
Thallium
Vanadium
Zinc
                         x
                         x
  x
  x
  x
  x
X
X
X

X
X

X
X
X
X
X
X
X
X
X
X


X

X

X

X
X

X
X
X
X
X
X
X
X
X
X
X
X

-------
3.2.7 Feasibility Study

As a result of the Round Two RI, an FS was initiated in 1995 to address chemicals of concern  (COCs) in each
media of concern and potential ecological concerns.  COCs are derived from the list of COPCs and ECOCs
identified in baseline RAs that produce 95 percent of the unacceptable human health or ecological risks.
Remediation Levels (RLs) were developed for each COG in each medium.  RAAs were then developed and evaluated
for COCs in media of concern in the FS.   These RAAs are summarized later in this ROD.

During the development of the FS, media of concern were re-prioritized from groundwater  (focus of the Draft
FS) to Area A soils.   The basis for the re-prioritization included the guality of shallow groundwater (i.e.,
groundwater is not potable) in the vicinity of Site 12, levels of inorganics  (primarily lead) in Area A and
the potential for current human and ecological exposure to affected media.  The highly erosional nature of
Site 12 and the potential impact on Ballard Creek were also considered.  As a result, groundwater RAAs
featured in die Draft FS were placed in Appendix F and RAAs for Area A soil were developed.  Area A soil RAAs
are featured in both the Draft Final and Final FS Reports.

4.0  HIGHLIGHTS OF COMMUNITY PARTICIPATION

The Final RI and FS reports, along with the Final PRAP for Site 12 at WPNSTA Yorktown were released to the
public on July 1, 1996.  These documents were made available to the public in the information repositories
maintained at the following locations:

       •      York County Public Library
       •      Gloucester Public Library
       •      Newport News City Public Library
              WPNSTA  Yorktown,  Environmental Directorate,  Building 31-B

A notice of availability of the RI/FS reports and the PRAP was published in The Daily Press on June 30,1996.
A public comment period regarding Site 12 was held from July 1, 1996 to August 14, 1996; and a public meeting
regarding the same was held on July 26,  1996 at the York County Recreational Services Meeting Room, 301
Goodwin Nock Road.  The purpose of the public meeting was for the Department of the Navy (DoN),  United States
Environmental Protection Agency  (USEPA), and Commonwealth of Virginia representatives to answer guestions and
accept public comments on the PRAP for Site 12.   Response to the comments received during the comment period
are included in the Responsiveness Summary of this ROD.

This decision document presents the selected remedial action for Site 12 chosen in accordance with CERCLA, as
amended by the Superfund Amendments and Reauthorization Act (SARA) and, to the extent practicable, the NCP.
The decision for Site 12 is based on the administrative record.

5.0  SCOPE AND ROLE OF THE RESPONSE ACTION

The selected remedial action is the overall strategy for the Site 12 study area.  The action will remediate
the contaminated soil in Area A  (OU III) and will monitor the guality of the groundwater, surface water, and
sediment across the study area  (OU V).  No Action is specified for Area B/C and Wood/Debris Disposal Area
soils  (OU IV).  No further actions are anticipated to be conducted at Site 12.

Based on the results of the baseline RAs, there are three potential media of concern present at Site 12:
contaminated soil in Area A; TCE-contaminated groundwater in the Cornwallis Cave  (shallow)  aguifer, and
inorganic- and polynuclear aromatic hydrocarbon (PAH)-contaminated sediment in Ballard Creek.  Of these three
media, the FS determined that only the contaminated soil in Area A  (i.e., OU III) will reguire remediation.
COCs for Area A soils are presented in Table 5-1.  Figure 5-1 illustrates Area A and the extent of
contaminated soil as defined by an exceedance of the USEPA lead action limit of 400 milligrams per kilogram
(mg/Kg).  Soil concentrations exceeding 400 mg/Kg of lead occur in ash and ash affected soils.  The presence
of ash in Area A is an indicator of past disposal practices associated with open burning practices and
operation of the incinerators at Site 12.  An evaluation of the extent of contamination due to other COCs at
Area A indicates that remediation of site soils using the USEPA lead action limit of 400 mg/Kg will result in
the remediation of all soil contaminants, organics as well as inorganics, to levels that protect human health
and the environment.

Groundwater in the Cornwallis Cave aguifer will not be subjected to remediation at this time for the
following reasons:  1) groundwater in the Cornwallis Cave aguifer and the Upper Yorktown-Eastover aguifer are
not currently used for any purpose and are not potable because of low yields, high iron, pH and other
characteristics at WPNSTA Yorktown and TCE did not exceed its risk-based remediation level derived assuming

-------
future beneficial use; and 2)  flow rates and the potential existence of solution cavities common to the
Cornwallis Cave aquifer at Site 12 present technical limitations to the effectiveness of any groundwater
extraction or in situ treatment system.   Because groundwater is not potable in the vicinity of the site, a
future beneficial use scenario was used in the development of risk based RLs.   Beneficial use of underlying
groundwater was assumed to be the washing of cars or watering of lawns.  Potential exposure associated with
this future potential exposure scenario will be discussed in detail in Section 7.0 of this document.

-------
                                            TABLE 5-1
      Chemical of Concern

    1,3.5,-Trinitrobenzene


    Antimony

    Cadmium


    Manganese

    Lead
                                       CHEMICALS OF CONCERN
                                  SITE 12 - AREA A SURFACE SOILS
                                 NAVAL WEAPONS STATION YORKTOWN
                                        YORKTOWN, VIRGINIA
Maximum Value
(mg/Kg)
3.7

28. 5L
25.7

1,230
3,240
Area of Highest
Detection
Area A

Area A
Area A

Area A
Area A

Rationale
Human Health/
Ecological
Human Health
Human Health/
Ecological
Human Health
Human Health
Background
(mg/Kg)
ND

9.2 to 11L
1.3K to 1.5

7.6L to 491
6.4 to 43.1
    Notes:

    ND = Not detected
    L  = Biased Low
    K  = Biased High
    mg/kg = milligrams per kilogram

-------
Although COCs were detected in the surface water and sediment of Ballard Creek, Ballard Creek will not be
subjected to remediation at this time for the following reasons: 1) there are no unacceptable current or
future potential human health risks associated with exposure to surface water or sediments; 2) there are no
unacceptable ecological risks; 3) there are no enforceable chemical-specific applicable or relevant and
appropriate reguirements (ARARs) for sediment; and 4) treatment of the sediments would reguire dredging which
would be more harmful to the environment than the presence of contamination. However, OU V is not exempt
from being considered for remediation in the future.

Human health risks and potential ecological effects associated with Area B/C and Wood/Debris Disposal Area
soils fall within acceptable ranges. Therefore, no action is specified for OU IV.

Although RAAs were not proposed for groundwater in the Cornwallis Cave aguifer, surface water or sediment in
Ballard Creek (i.e., OU V), a monitoring program will be implemented to ensure that the groundwater guality
and surface water/sediment guality do not further deteriorate. The monitoring of groundwater will be
conducted as per the NCP because contamination in the shallow aguifer will result in future property use
restrictions in the WPNSTA Master Plan. The monitoring program for Ballard Creek surface water and sediment
will be implemented as agreed to by USEPA Region III, the Commonwealth of Virginia and the Navy. The OU V
monitoring program will include periodic sampling and analysis of groundwater in the Cornwallis Cave
(shallow) and Yorktown-Eastover (deep) aguifers, and surface water and sediment in Ballard Creek. The
details of the program (e.g., sampling location freguency, duration, and analyses) will be identified in a
long-term monitoring work plan that will be prepared as a primary document under the Federal Facility
Agreement (FFA). If the monitoring program indicates that groundwater, surface water, or sediment guality is
deteriorating, remediation of these media may be considered. In addition, long-term monitoring (as per the
NCP) will be included under the selected remedy for Area A (OU III) soil. Long-term monitoring is reguired
to determine the overall protectiveness of the remedy. Goals for long-term monitoring will be presented in
Section 10.0 of this document.

6.0 SUMMARY OF SITE CHARACTERISTICS

This section briefly describes the analytical results of the Round Two RI and the nature and extent of
contamination (i.e., the site characteristics) in surface soil, subsurface soil, groundwater, surface
water, and sediment at Site 12.

6.1 Surface Soil

Surface soil at Site 12 has been impacted by site operations. Area A has been most affected as indicated by
the presence of inorganics (including lead), PAHs, and relatively low levels of PCBs. Low levels of TCE,
pesticides, and nitramine compounds also were detected. Also affected, but to a lesser degree, are Area B/C
and the Wood/Debris Disposal Area. Although no VOCs, PCBs, or nitramine compounds were detected in Area B/C,
PAHs and inorganic analytes were detected. To an even lesser extent, the Wood/Debris Area has been affected
by PAHs and inorganic contamination. Tables 6-1 through 6-3 present a summary of select surface soil COPCs
for each area.

The source of surface soil contamination is apparently the past disposal of wastes at Site 12. Area A has
been most affected by the receipt of ashes from the incinerator, open burning, and from the landfilling of
other materials (construction debris, steel containers, and piping) as evidenced by surface debris.

PCBs detected in Area A could be associated with the historical use of antifoulans on underwater mines and
mine cable. Pesticides are likely present at Site 12 because of past legal application of these
constituents. The presence of PAHs and inorganic contaminants can most likely be attributed to the disposal
of ashes from the incinerator and open burning.

6.2 Subsurface Soil

Subsurface soil at Site 12 has been impacted by past site operations at Area A. With respect to organic
contamination, PAHs and one PCB (Aroclor-1260) were detected in two shallow subsurface (2 to 4 feet below
ground surface [bgs]) soil samples.

-------
            TABLE 6-2
       SITE 12 - AREA B/C
   SURFACE SOIL COPC SUMMARY
NAVAL WEAPONS STATION YORKTOWN
      YORKTOWN, VIRGINIA

       Contaminant
     Frequency/Range (1)(2)
RGO
                                                                    Station-wide Background(3)
                                                                                   Range of
                                                               No.  of Positive
                                                                  Detects/
    Contaminant  (1)    No.  of Samples         (mg/Kg)           No.  of Samples

 Semivolatiles:

   Benzo(a)anthracene
   Benzo(a)pyrene
   Benzo(b)fluoranthene
   Benzo(k)fluoranthene
   Chrysene
   Indeno  (1,2,3-cd)
   pyrene
 Inorganics:

   Aluminum
   Antimony
   Arsenic(as  carcinogen)
   Beryllium

 Notes:

 COPC = Contaminant  of potential  concern
 ND  = Not detected
 RGO = Remediation  Goal  Option

(1)  Organic concentrations converted  from micrograms per kilogram (mg/Kg)  to milligrams per kilogram (mg/Kg),  Inorganic
    concentrations reported in mg/Kg.
(2)  J = Analyte  was  positively identified,  value is  estimated.
    K = Analyte  was  positively identified,  value is  biased high.
    L = Analyte  was  positively identified,  value is  biased low.
(3)  Anthropogenic samples  used for comparison to organic COPCs.
No. of Positive
Detects/
No. of Samples
5/11
5/11
le 7/11
le 5/11
6/11
5/11
11/11
1/11
fen) 11/11
11/11
Range of Positive
Detection
(mg/Kg)
0.1J-0.45
0.11J-0.52
0.057J-1.7
0.068J-0.52
0.041J-0.94
0.052J-0.31J
2,780-12,000
3.5L
1.3-8.5
0.08-038
                                          2/13
                                          2/13
                                          3/13
                                          2/13
                                          3/13
                                          1/3
                                          44/44
                                           2/42
                                          44/44
                                          31/44
Positive
'etection
mg/Kg)
0.12J-0.
0.14J-0.
0.23J-0.
0.12J-0.
0.14J-0.
0.16J
1,960-19
9.2L-11L
0.46L-63
0.23J-0.
Adolescent /Adult
s
24J
18J
5
13J
27J

,200
.9
93J
Trespassers
(mg/Kg)
34
3.4
34
340
3.4
34
420,000.0
170
60.0
15.0

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                                                    TABLE 6-3
                                         SITE 12 - WOOD/DEBRIS DISPOSAL AREA
                                               SURFACE SOIL COPC SUMMARY
                                            NAVAL WEAPONS STATION YORKTOWN
                                                    YORKTOWN,  VIRGINIA
                                     Contaminant
                                   Frequency/Range (1)(2)
No. of Positive
Detects/
No. of Samples
4/8
2/8
le 5/8
le 3/8
4/8
:ene 1/8
>yrene 2/8
8/8
>gen) 8/9
6/8
Range of Positive
Detection
(mg/Kg)
0.042J-2
0.17J-1.6
0.047J-2.6
0.039J-0.82
0.058J-2.1
0.21J
0.11J-0.58
3,530-9,470
2.5-10.6
0.22-0.7
       Station-wide Background(3)
                      Range of
  No. of Positive     Positive
     Detects/        Detections
No. of Samples       (mg/Kg)
     RGO

Adolescent/Adult
    Trespassers
    (mg/Kg)
       Contaminant  (1)

    Semivolatiles:

      Benzo(a)anthracene
      Benzo(a)pyrene
      Benzo(b)fluoranthine
      Benzo(k)fluoranthene
      Chrysene
      Dibenzo(a,h)anthracene
      Indeno  (1,2,3-cd)  pyrene
    Inorganics:

      Aluminum
      Arsenic (as carcinogen)
      Beryllium

    Notes:

    COPC =  Contaminant  of potential concern
    ND = Not  detected
    RGO = Remediation Goal Option

(1)  Organic concentrations converted from micrograms per kilogram (Ig/Kg)  o milligrams per kilogram (mg(Kg), Inorganic
    concentrations  reported in mg/Kg.
(2)  J = Analyte was positively identified,  value is estimated.
    K = Analyte was positively identified,  value is biased high.
    L = Analyte was positively identified,  value is biased low.
(3)  Anthropogenic samples used for comparison to organic COPCs.
2/13
2/13
3/13
2/13
3/13
0/13
1/13
44/44
44/44
31/44
0.12J-0.24J
0.14J-0.18J
0.23J-0.5
0.12J-0.13J
0.15J-0.27J
ND
0.16J
1,960-19,200
0.46L-63.9
0.23J-0.93J
34.0
3.4
34.0
340.0
3,400.0
3.4
34.0
420,000.0
60.0
15.0

-------
inorganic analytes (including lead) were detected in subsurface soil samples at concentrations exceeding the
Station-wide background levels. The presence of these constituents in Area A subsurface soil is associated
with the presence of ash from the incinerator and open burning, not the leaching of contaminants to deeper
soil (see Table 6-4). Because these soils fall in shallow subsurface soil horizon, Remediation Goal
Objectives (RGOs) for surface soils are presented for comparative purposes.

Subsurface soil samples obtained throughout Site 12 proper indicate that areas other than Area A are not
significantly impacted by past site operations. Inorganics detected in the subsurface soil samples outside
of Area A appear to be similar to Station-wide background conditions. However, because of the debris present
in these areas, subsurface soil samples were not obtained directly in the disposal areas (See Table 6-5).

6.3 Groundwater

Groundwater in the Cornwallis Cave aquifer (i.e., the shallow aguifer) at Site 12 has been impacted by past
Station operations. TCE was detected in five of seven on-site monitoring wells. In addition, TCE was
detected in 8 of 11 monitoring wells situated upgradient and side-gradient of Site 12. The highest
concentration of TCE (3,300 micrograms per liter [Ig/L]) was detected in a groundwater seep (15SW12)
downgradient of the highest concentration of TCE detected in groundwater (12GW15 at 1,300 Ig/L). These
samples are located on the west side of Barracks Road between Industrial Area Buildings 3 and 4. Based on
the history of Buildings 3, 4, 5, and 6, it is likely that TCE in the shallow groundwater is associated with
former USTs that received waste oil and solvents and historical use of TCE as a degreaser in the Industrial
Area. Groundwater in the shallow Cornwallis Cave aguifer and the deeper upper Yorktown-Eastover aguifer is
not currently used for drinking purposes at WPNSTA Yorktown. Groundwater from the Cornwallis Cave aguifer
contains relatively high concentrations of iron, manganese and low water yields are characteristic of the
formation. Groundwater in the upper Yorktown-Eastover exhibits relatively high pH values throughout WPNSTA
Yorktown and, therefore, could not be used as a potable source without pre-
treatment. Groundwater in both the Cornwallis Cave aguifer and the Yorktown-Eastover aguifer exceeds the
Commonwealth of Virginia hardness criteria in most wells. As such these water bearing units could be
considered Class III aguifers. Table 6-6 presents chemical data supportive of Class III aguifer status.
These data have been compiled from background monitoring wells located throughout the Station and have not
been affected by Site 12 activities. Because groundwater in the Cornwallis Cave aguifer and upper
Yorktown-Eastover aguifer cannot be used for future potable purposes without pretreatment, a future
beneficial use scenario was developed to evaluate potential exposure. Human exposure under the future
beneficial use scenario will be discussed in Section 7.0. TCE concentrations detected in shallow groundwater
do not exceed the remediation level (16,000 Ig/L) derived for the future beneficial use of Site 12
groundwater.

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                                                         TABLE 6-5

                                                      SITE 12.- PROPER
                                                SUBSURFACE SOIL COPC SUMMARY
                                               NAVAL WEAPONS STATION YORKTOWN
                                                     YORKTOWN, VIRGINIA
                                     Contaminant
                                   Frequency/Range  (1)(2)
       Contaminant
    Inorganics:
(1)
      Aluminum
      Antimony
      Arsenic (as carcinogen)
      Beryllium
      Chromium
      Manganese
      Vanadium
No. of Positive
   Detects/
No. of Samples
                2/8
                8/8
                3/8
Range of Positive
 Detections
   (mg/kg)
                   4,230-28,800
                    7.1L-230L
                     0.58-20.3
                    0.23-0.45K
                     3.6-90.6
                    17.4-1,040
                      6.6-256
    Station-wide Background  (3)
                   Range of
No. of Positive    Positive
    Detects/      Detections
No. of Samples      (mg/Kg)
                             16/16
                              2/13
                             16/16
                             13/16
                             16/16
                             16/16
                             16/16
                 2,710-28,200
                   8.5L-31.3L
                   0.23J-42.7
                    0.3J-9.8
                   5.2L-33.5
                   3.5J-2,940
                    3.6J-330
    Notes:

    (1)   Organic concentrations converted from micrograms per kilogram (Ig/Kg) to milligrams per kilogram
         (mg/Kg),  Inorganic concentrations reported in mg/Kg.
    (2)   J = Analyte was positively identified, value is estimated.
         K = Analyte was positively identified, value is biased high.
         L = Analyte was positively identified, value is biased low.
    (3)   Anthropogenic samples used for comparison to organic COPCs.

-------
Inorganic analytes detected in groundwater are similar to Station-wide background conditions. Groundwater
samples obtained from the Yorktown-Eastover aguifer did not exhibit VOC contamination, indicating that
vertical migration of contamination through the Yorktown confining unit has not occurred. The horizontal and
vertical extent of TCE in Site 12 groundwater is presented in Appendix A, Figures A.I through A.8 of this
ROD.

6.4 Surface Water

Surface water at Site 12 has been slightly impacted by site operations. Relatively low concentrations of
VOCs (TCE, cis-1,2-dichloroethene, and 1,1-dichloroethene) were detected in samples collected from the stream
channels and from Ballard Creek. Of the VOCs, TCE was detected most freguently with concentrations ranging
from 0.5J to 6.5 Ig/L. Vinyl chloride (7 Ig/L) was detected in one surface water sample obtained from the
stream channel near the toe of the Wood/Debris Disposal Area. TCE was also detected in an upstream sample
along Ballard Creek (12SW09 at 0.5J Ig/L). The source of TCE at this location is most likely the groundwater
seep downgradient of the Industrial Area which will be addressed in OU V of this ROD by long-term monitoring
of groundwater. In addition, TCE was detected upstream of SSA 15 at sample location 15SW10 at 340lg/L. TCE
does not, however, exceed its freshwater ambient water guality criteria for both acute and chronic effects
(45,000 Ig/L and 21,900 Ig/L, respectively), nor does TCE exceed the
Commonwealth of Virginia Water Quality Standard of 807 Ig/L. Furthermore, surface water concentrations of
chlorinated volatiles and other contaminants do not pose unacceptable current or future human health risks.
PAHs, PCBs, and nitramine compounds were not detected in the surface water samples. Figure 6-1 presents
concentrations of TCE detected in Ballard Creek surface water.

6.5 Sediment

Sediment at Site 12 has been impacted by past site operations. The primary contaminants detected in sediment
samples included PAHs, pesticides, PCBs, and inorganics. Figure 6-2 presents COG concentrations that exceed
corresponding Effect Range-Median (ER-M) values. In general, environmental effects are considered probable
when sediment concentrations exceed ER-Ms. Table 6-7 presents maximum detected values for sediment
contaminants exceeding Effects Range-Low (ER-L; concentration in sediment above which ecological effects are
possible) and ER-M values. Exceedances of ER-L and ER-M values occur mainly in the sediment samples obtained
from Site 12 drainage ditches. Highest sediment concentrations of site related COCs occur mainly at sediment
location SD12, where PAHs, PCBs, lead and mercury were detected. This sediment location is located directly
downstream of Area A and, as such, is indicative of contamination in Area A soils. Area A soil will be
addressed by the remedy selected in this ROD. ER-M exceedences; in sediments of Ballard Creek proper are
generally associated with non-site related contaminants such as
pesticides (alpha-chlordane and 4,4'-ODD) or occur in deeper sediments obtained from the 4 to 8 inch depth
interval (cadmium at location SD17-02). Therefore, risk to aguatic ecological receptors in Ballard Creek
posed by Site 12 is limited.

Furthermore, potential human health cancer risks associated with current and future sediment exposure fall
within USEPA's acceptable risk range. Similarly, adverse noncarcinogenic human health risks are not expected
to occur subseguent to exposure. This is indicated by the Hazard Index (HI) values below 1.0 for sediment
exposure. Therefore, RAAs were not developed for this medium.

7.0 SUMMARY OF SITE RISKS

As part of the Round Two RI, a baseline RA was conducted which included both a human health RA and an
ecological RA to evaluate potential risks to human receptors and the environment resulting from the presence
of COPCs at Site 12. The following subsections describe the results of these RAs.

7.1 Human Health Risk Assessment

As part of the human health RA, COPCs were identified in the surface soil, subsurface soil, shallow
groundwater, deep groundwater, surface water, and sediment. These COPCs included VOCs, PAHs, pesticides,
PCBs, nitramine compounds, and inorganics including lead and cadmium. For each potential receptor, total
risks were estimated by disposal area (Area A, Area B/C and the Wood/Debris Disposal Area) for current
trespasser and future potential residential receptors as discussed below. Potential carcinogenic and

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noncarcinogenic risks were estimated for the COPCs. Carcinogenic risk is expressed, for those carcinogenic
COPCs having cancer slope factors (CSFs), as an incremental cancer risk (ICR) value which is the estimated
incremental probability of an individual developing cancer over a lifetime because of exposure to a potential
carcinogen. Current Federal guidelines for acceptable carcinogenic risks are in the range of 1 x 10 -06 to 1
x 10 -04 (one in one million to one in ten thousand). Systemic or noncarcinogenic health effects are
evaluated through the derivation of a HI, which is the ratio of contaminant uptake to a reference dose (RfD)
value. Exposure resulting in a chemical uptake egual to or exceeding the RfD value ran result in the
expression of adverse noncarcinogenic health effects. The HI value is, therefore, an indicator of potential
noncarcinogenic adverse health effects such that an HI value greater than or egual to 1.0 indicates the
potential for adverse systemic health effects. An HI below 1.0 indicates that systemic effects will not
occur subseguent to exposure.

7.1.1 Current Potential Receptors

Potential current receptors to COPCs detected in environmental media at Site 12 include adolescent and adult
trespassers. The total ICR values for these current scenario receptors fell within the generally acceptable
target risk range of 1 x 10 -04 to 1 x 10 -06 as determined by the USEPA. His for current potential human
receptors in Area B/C and the Wood/Debris Disposal Area fell below 1.0. However, the total HI value estimated
for the potential receptors in Area A exceeded 1.0. These His were 1.2 for the adult trespasser, and 1.5 for
the adolescent trespasser. Contaminants responsible for these elevated His are.1,3,5-TNB, antimony, cadmium,
and manganese in Area A soil.

Cancer risks to current potential receptors exposed to surface water and sediment fall within USEPA's target
range of 1 x 10 -04 to 1 x 10 -06 and HI values below 1.0, indicating that systemic adverse health effects
will likely not occur. There is no current potential exposure to groundwater underlying Site 12. Table 7-1
presents a summary of risk values and His by area for current potential human receptors.

7.1.2 Future Potential Receptors

The potential human receptors evaluated under the future scenarios include future adult and young child
residents and future adult construction workers. Property use at Site 12 will remain the same in the
foreseeable future and future residential development of Site 12 by the Navy is highly unlikely (although not
prohibited). Because of poor groundwater guality in both the Cornwallis Cave aguifer and the deeper and
Upper Yorktown-Eastover aguifer, groundwater would not be used for drinking purposes. Untreated groundwater
could however be used for beneficial purposes such as watering lawns or washing cars. For the sake of
conservatism, future-beneficial use of Site 12 groundwater was evaluated in the FS report to establish
groundwater RL values.

7.1.2.1 Future Residents

Because of the relatively high concentrations of lead detected in Area A surface soil, the USEPA Lead Uptake
Biokinetic (UBK) Model was used to determine if accidental ingestion exposures to lead by future resident
children in Area A surface soil would result in unacceptable blood lead levels. The model indicated a 45
percent probability that blood lead levels in young children would exceed the action level of 10 micrograms
per deciliter (Ig/dl) following accidental surface soil ingestion in Area A. According to USEPA guidance,
exceedence of this blood lead level may result in unacceptable risks to this receptor group.

Total ICR values estimated for future potential adult and child receptors at Site 12 exceed USEPA's target
risk range of 1 x 10 -04 to 1 x 10 -06. Exceedence of the risk range is associated with the reasonable
maximum exposure by future residents to TCE in the shallow groundwater, if it is used in the future for
drinking purposes. Central tendency (i.e., average) estimates of potential exposure and subseguent cancer
risks associated with potable groundwater usage fall within the upper end of the target risk range,
Groundwater also contributes to the total HI value, which exceeds 1.0 indicating the potential for adverse
noncarcinogenic health effects to occur subseguent to exposure. An evaluation of potential exposure by
pathway for both adult and child receptors indicates that exposure to Area A soils and potable use of
groundwater account for all of the unacceptable risks and HI values associated with Site 12. Tables 7-2
through 7-4 present the risk values and His associated with future residential property use and the future
potable use of groundwater at Site 12.

Because of groundwater guality in both the shallow Cornwallis Cave aguifer and the Upper Yorktown-Eastover
aguifer, potable use of these water-bearing units is highly unlikely without pretreatment Therefore, the

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future beneficial use of groundwater was evaluated in the FS report. The future beneficial use scenario was
assumed to be lawn watering and washing of cars. This scenario combines dermal and ingestion exposure
pathways and assumes that adults and adolescents (7 to 15 years of age) would likely be involved in
beneficial use activities. An RL of 16,000 Ig/L was derived for TCE to prevent the occurrence of future
noncarcinogenic adverse health effects. TCE concentrations do not approach or exceed 16,000 Ig/L at any
monitoring well location associated with Site 12.

ICR values and HI values derived for Area B/C soil and Wood/Debris Disposal Am soil, surface water and
sediments fall within the USEPA target risk range and are less than 1.0, respectively. The UBK model was not
used for either Ares B/C soil or the Wood/Debris Disposal Area soil because lead concentrations detected in
these areas were similar to Station-wide background.

7.1.2.2 Future Adult Construction Worker

Future potential adult construction workers could be exposed to COPCs in subsurface soil during future
building/excavation activities at Site 12. The total ICR estimated for this receptor was within USEPA's
acceptable target risk range of 1 x 10-04 to 1 x 10-06; however, the total HI (1.5) exceeded 1.0 because of
the presence of antimony and other inorganics in Area A only. Antimony and inorganic concentrations detected
in subsurface soil sampling locations outside of Area A were similar to concentrations observed in
Station-wide background subsurface soil. These constituents therefore, are not attributable to past Site 12
activities.

7.2 Ecological Risk Assesment

During the ecological RA, ECOCs were identified in the surface soil, surface water, and sediment at Site 12.
These ECOCs included VOCs, semivolatile organic compounds (SVOCs), pesticides, PCBs, nitamines, and
inorganics. The results from the ecological RA indicated that overall SVOCs, pesticides, PCBs, nitamine
compounds, and inorganics detected in Area A soil appear to have the most potential to affect ecological
receptors at Site 12. Specific conclusions with respect to the aguatic and terrestrial ecosystems are
presented below.

7.2.1 Aguatic Ecosystem

Surface water concentrations of cadmium, chromium and cyanide exceeded surface water screening levels (SWSLs)
and were elevated above background concentrations (see Table 7-5). Cadmium exceeded its chronic SWSL in two
surface water samples. One surface water sample was obtained from the ditch adjacent to the Wood/Debris
Disposal Area (12SW16) and the other sample was obtained from location 12SW17 in Ballard Creek proper.
Cadmium was not detected in surface water samples obtained from the ditch bisecting Area A or downstream
surface water locations in Ballard Creek proper between the Area A and 12SW17. It is also important to note
that cadmium was detected in dissolved (filtered) surface water samples and not total (unfiltered) surface
water samples. As such, the presence of cadmium in surface water samples may be an analytical anomaly and
not associated with Site 12. Furthermore, detected concentrations of cadmium do not exceed its acute SWSL
only the more conservative chronic SWSL value.

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                                                            TABLE 7-5

                                 FREQUENCY AND RANGE OF DETECTION OF SELECTED SURFACE WATER ECOCs
                                        COMPARED TO USEPA REGION III FRESHWATER SCREENING LEVELS
                                                              SITE 12
                                                 NAVAL WEAPONS STATION YORKTOWN
                                                          YORKTOWN, VIRGINIA
                       Surface Water Screening
                            Levels  (SWSLs)
                          Contaminant Frequency/Range
     Analyte
Organics  (Ig/L):
1,2-Dichloroethane
cis-1,2-Dichloroethene
Trichloroethene

Vinyl Chloride
Inorganics  (Ig/L):
Cadmium
Chromium
Cyanide
Lead

Notes:
                           Acute
                                      Chronic
 218,000    20,000(1)
  11,600       NE
  45,000(2)   21,900
  11,600

 13.6(2)(3)
   16(1)
   22(1)
332.6(1)(3)
 NE

0.15
1(4)
5.2
 1
No. of Positive
Detects/No, of
    Samples

      /10
     2/10
     6/10

     1/10

     2/10
     6/10
     1/6
     5/10
                         Range of Positive
                            Detections

                               0.6J
                              1.2-10
                            0.5.J - 6.5
 7.7J

2K - 8.4K
4K - 10K
  230
 1.1-2
                                                            No. Of Positive
                                                            Detects Above
                                                            Lowest SWSL     Background
 0
 0
 0

NA

 2
 6
 1
 5
     ND
     ND
     ND

     ND

     ND
    9.8J
     ND
1.6J - 15.9
  Ecological
Contaminant of
   Concern?

     NO
     NO
     NO

     NO

    YES
    YES
    YES
     NO
                                                             Reason for Exclusion

                                                                 Below SWSL
                                                                 Below SWSL
                                                                 Below SWSL/
                                                               Lab Contaminant
                                                                 Below SWSL
                                                                                               Background
 (1)  USEPA, 1987.
 (2)  USEPA, 1992b
 (3)  Value based on an average hardness of 301.4 mg/kg CaC03
 (4)  Chromium VI level
                                                                       ECOC =  Ecological contaminants of concern
                                                                       NE   =  Not Established
                                                                       NA   =  Not Applicable
                                                                       J    =  Estimated value
                                                                       K    =  Value biased high
                                                                       L    =  Value biased low
                                                                       Ig/L =  microgram per liter
                                                                       SWSL =  surface water screening level

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Chromium was detected in total (unfiltered) surface water samples obtained from both the ditches and Ballard
Creek proper in excess of its chronic SWSL. Chromium was not detected in dissolved (filtered) surface water
samples. The presence of chromium in surface water could, therefore, be associated with suspended sediments
in the water column present because of sampling techniques and the potential to disturb sediments during the
sampling process. Cyanide was detected in only one surface water sample (12SW15) obtained from an upstream
location in the ditch adjacent to the Wood/Debris Disposal Area.

Cyanide was not detected in the dissolved (filtered) sample obtained at location 12SW15 nor was it detected
in dissolved or total surface water samples at any other location. Because of the sporadic nature of their
occurrence and the relatively low concentrations observed in surface water (i.e., above the chronic SWSL but
below the acute SWSL), COCs detected in surface water will not adversely affect aguatic receptors in Ballard
Creek.

The benthic community at Site 12 was evaluated to determine whether sediment COCs have had a deleterious
effect on the guality of Ballard Creek. To determine the potential effect of sediment COCs on sediment/
water guality, the Macroinvertebrate Biotic Index (MBI) was derived for each sampling station. The sediment
at Site 12 contained elevated levels of SVOCs, pesticides, PCBs, and inorganic constituents. The presence of
pesticides in Site 12 sediments is likely because of past legal application of these constituents at WPNSTA
Yorktown, not specific site activities. As such, pesticides are not considered to be site related. The MBI
is a numeral indication of the type and number of benthic macroinvertebrate taxa at any sampled location.
The MBI therefore provides an indication of general stream/water guality. The MBI is evaluated in the
following manner:

MBI <5.24 525-5-95 5.96-6.67 6.69-7.70 >7.71

Water Quality Excellent Good Water Good/Fair Fair Water Poor Water
Classification Water Quality Quality Water Quality Quality Quality

Benthic, macroinvertebrate results are presented on Figure 7-1.

Benthic results indicate that COCs from Site 12 pose limited risk to aguatic receptors in Ballard Creek, and
that the benthic environment may also be adversely impacted by other ecological stressors. Other potential
stressors to the benthic community that may create an unfavorable habitat include disturbances from Station
operations or excessive stormwater runoff and erosion into the shallow streams. Sediment samples were
subjected to grain size analysis to determine the physical characteristics of the sediment microenvironment
(Figure 7-2). In general, upstream sediment locations where the MBI is lower, (indicating better water
guality) are comprised of fine sands whereas downstream locations are comprised of a mixture of fine, medium
and coarse sand, silts/clays and some gravel. Sediment samples obtained from intermittent streams that
converge with Ballard Creek have a relatively higher percentage of medium sands, coarse sands and silt/clay.
Erosion events along the Ballard Creek watershed explain the general changes observed in sediment grain size
results and contribute to higher (indicating poor water guality) observed MBI values in downstream
locations. Furthermore, benthic sampling stations at Site 12 had species abundance and densities similar to
background stations on similar water bodies.

7.2.2 Terrestrial Ecosystem

Area A is the most adversely impacted terrestrial environment at Site 12. Risk to the terrestrial
environment in Area A is a result of surface soil concentrations of PAHs, PCBs, nitramine compounds, and
inorganics. Area B/C soils exhibited concentrations of PAHs and several inorganic constituents which do not
produce significant potential ecological risks. The Wood/Debris Disposal Area is similar to Area B/C in that
soils exhibit PAHs and inorganic constituents. These constituents do not pose significant potential
ecological risks. The following provides the terrestrial ecosystem conclusions for Area A, Area B/C, and the
Wood/Debris Disposal Area. Quotient indices (Qis) derived for these areas using terrestrial uptake models
are presented on Table 7-6.

QIs are derived by calculating a potential uptake or total daily intake (TDI) for each potential ecological
receptor. The TDI considers uptake from the incidental ingestion of dust, dietary uptake
and uptake from drinking water. The TDI is then compared to a toxicity reference value (TRV) in the
following manner.

-------
Where:

n = the total number of individual ECOCs

QIs are conservative indicators of potential effects on terrestrial receptors. A QI equal to or exceeding
1.0 indicates a potential effect. A QI of less than 1.0 indicates that effects are unlikely to occur. The
following subsection provides discussions concerning potential ecological effects for each Site 12 area using
flora and fauna toxicity.

7.2.2.1 Area A

Exceedences of soil flora and fauna toxicity values indicate that concentrations of PAHs, PCBs, nitramine
compounds, and inorganics, may be affecting the terrestrial environment. In addition, concentrations of
1,3,5-TNB, barium, cadmium, iron and selenium detected in Area A produce relatively high QI values indicating
a potential risk to terrestrial receptors in this area. The occurrence of these contaminants in Area A soils
are also responsible for QIs exceeding 1.0 for several terrestrial species of concern including the
White-tailed Deer, Bobwhite Quail and Eastern Cottontail Rabbit.
Area B/C

PAHs and inorganics detected in Area B/C exceeded conservative flora and fauna toxicity values.

However QI values indicate little risk from soils to terrestrial ecological receptors because risks
demonstrated in Area B/C terrestrial models were driven by the presence of cadmium in the surface v. er
component of the soil model. When surface water is removed from terrestrial uptake models, QIs for all
species of concern fall below 1.0 indicating that ecological effects will not occur. The exception is the
shrew which, because of conservatism used in the estimation of dietary intake, exceeds 1.0 for Area B/C and
Station-wide background as well. As a result, limited potential ecological risk is posed to terrestrial
receptors in Area B/C. The model assumes that 90 percent of the shrews diet is comprised of invertebrates
and the remaining 10 percent is vegetation. The current data base for invertebrates concerning contaminant
uptake is limited. Therefore, invertebrates were represented by earthworms which were assumed to
bioaccumulate 100% of all Site 12 soil contaminants. Using this approach to estimate dietary intake for the
shrew is overly conservative because background concentrations for inorganics including cadmium result in QI
values exceeding 1.0. If the model for the shrew was accurate, shrews would likely not exist at WPNSTA
Yorktown because of background soil conditions. This is not the case because short-tailed shrews were
identified during the natural heritage resource inventory conducted by the Virginia Department of
Conservation and Recreation Division of Natural Heritage at WPNSTA Yorktown between April and November 1990.
As such, the QI above 1.0 for the short-tailed shrew does not indicate a
genuine ecological risk at Area B/C.

7.2.2.3 Wood/Debris Disposal Area

PAHs detected at the Wood/Debris Disposal Area exceeded flora and fauna toxicity values.
However, QI values indicated limited potential ecological risk to terrestrial receptors.

Again, elevated QIs are based on the occurrence of cadmium in surface water. When the water component is
removed from the uptake modeling effort, QI values are below 1.0 with the exception of the Eastern
Cottontail Rabbit and the Shrew. The rabbit QI value exceeds 1.0 because of additivity of multiple chemicals
to which the terrstrial receptor could be exposed. Individual contaminant QIs do not exceed 1.0 for the
Eastern Cottontail Rabbit. Again, the shrew QI exceeds 1.0 because of conservatism in the estimation of
dietary intake of contaminants from soil invertebrates. The shrew QI value also exceeds 1.0 for Station-wide
soil background concentrations. Therefore, soil COCs pose limited risk to terrestrial ecological receptors in
the Wood/Debris
Disposal Area.

7.3 Conclusions of the Baseline RA

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Results of the baseline RA indicated that human receptors exposed to constituents in Area A soils may exhibit
potential adverse systemic health effects(i.e., HI>1.0). Constituents responsible for His above 1.0 include:
1,3,5-TNB; antimony; cadmium and manganese. Because an RfD value or a CSF is not available for lead, the UBK
model was used to evaluate the potential blood lead level for a future child exposed to Area A soil. The UBK
indicated a 45 percent probability that an exposed child would exhibit unacceptable blood lead levels. Area
A soils contain ECOCs that exceed flora and fauna toxicity values and resulted in elevated QIs for
terrestrial ecological receptors including the White-tailed Deer and the Bobwhite Quail. The
weight-of-evidence approach indicates that Area A soil could adversely affect the terrestrial ecology of Site
12.

Cornwallis Cave aguifer groundwater has been impacted by chlorinated solvents from former USTs in the
Industrial Area located upgradient of Site 12. Groundwater in the underlying Yorktown-Eastover aguifer does
not exhibit the presence of chlorinated volatiles indicating that the Yorktown confining unit effectively
separates these two water-bearing units in the vicinity of Site 12. The Cornwallis Cave aguifer and the
Yorktown-Eastover aguifer are not currently used for potable purposes. General water guality of these units
precludes their future potable use, however, no Commonwealth of Virginia or York County laws or restrictions
currently prohibit the installation of groundwater wells in either aguifer. If groundwater is used for
potable purposes in the future, unacceptable human risks (i.e.,ICR> 1 x 10 - 04) will result from the
presence of TCE in the medium. Although future potable use of groundwater is unlikely, groundwater as a
resource could be used for beneficial purposes such as watering lawns or washing of cars. A RL of 16,000
Ig/L for TCE was calculated for an adolescent or adult engaging in future beneficial use. TCE concentrations
in groundwater are below the beneficial use RL value. Groundwater from the Cornwallis Cave aguifer likely
discharges to Ballard Creek surface water along the southeaster portion of Site 12. Concentrations of
volatiles in surface water samples are relatively low and pose no unacceptable risk to human health and the
environment.

Human health risk and ecological effects associated with Area B/C and the Wood/Debris Disposal Area fall
within the generally acceptable risk range and do not, by weight-of-evidence, indicate the potential for
adverse terrestrial impacts. Surface water and sediment in Ballard Creek do not produce unacceptable human
health risks and pose minimal risk to the aguatic environment.

8.0 DESCRIPTION OF ALTERNATIVES

Based on the results of the RA, the FS report identified Area A soil (OU III) as an AOC for which remedial
alternatives should be developed. Remedial alternatives were also developed for the groundwater in the event
that long-term monitoring of groundwater indicated further degradation of groundwater resource (i.e.,
groundwater poses an unacceptable risk). These groundwater alternatives are presented in Appendix B of this
ROD. Because groundwater COCs do not exceed their corresponding beneficial use RL values, institutional
controls with long-term monitoring was the selected alternative for groundwater. Specifics of the long-term
monitoring program for groundwater will be developed as part of a long-term monitoring work plan which will
be considered a primary document under the FFA. Ballard Creek will also be considered as part for the
long-term monitoring for groundwater because shallow groundwater ultimately discharges to this surface water
feature (OU V). Because Ballard Creek surface water and sediment pose no unacceptable human health risks or
adverse ecological effects, remedial alternatives were not developed for these media. Because, human health
and ecological risks associated with Area B/C soil, Wood/Debris Disposal Area soil (OU IV) were within
generally acceptable ranges, remedial alternatives were not developed for this OU.

Various remedial technologies and process options were identified, screened, and evaluated during
the FS for OU III. Ultimately, the following six RAAs were developed for the remediation of
contaminated soil in Area A:
Soil RAA 1
Soil RAA 2
Soil RAA 3
Soil RAA 4
Soil RAA 5
Soil RAA 6
No Action
Institutional Controls, Monitoring, and Erosion Control
Soil/Clay (or clay eguivalent) Cover
Excavation and Landfill Disposal
In Situ Solidification/Stabilization
Excavation and Soil Washing
A summary of each RAA is presented below. The cost and time to implement are estimated values.

8.1 Soil RAA 1: No Action

Capital Cost: $0

-------
       •       Annual Operation & Maintenance (O&M)  Cost:    $0
              Soil RAA net present worth (NPW):             $0
       •       Time to Implement:                           0

Under the no action RAA, no additional remedial actions will be performed for the contaminated Area A soil at
Site 12.   The no action alternative is required by the NCP to provide a baseline for comparison with other
RAAs that provide a greater level of response.

8.2   Soil RAA 2:  Institutional Controls,  Monitoring, and Erosion Control

              Capital Cost:                                 $450,000
              Annual O&M Cost:                              $15,000
              Soil RAA NPW:                                 $680,000
       •       Time to Implement:                           Less than six months

Under Soil RAA 2, institutional controls, a long-term surface water montitoring program, and erosion
controls measures will be implemented.

Institutional controls will include land use restrictions in the WPNSTA Master Plan of Base instruction that
will limit future construction, residential development,  and placement of new wells at Site 12.

The long-term monitoring program will include periodic surface water sampling in the Area A stream channel
that discharges to Ballard Creek.  At least four samples will be spaced along the stream channel and the
samples will be analyzed for inorganics to ensure that soil contaminants do not migrate from Area A, and to
monitor erosion along the stream channel.

The erosion control measures will include rip rap and vegetative matting.  The rip rap will line the entire
length of the Area A stream channel, from its beginning to the ponded area located approximately 75 feet
northwest of the Station fence line.  Erosion control will also remediate affected sediments in the Area A
ditch stream channel be limiting direct contact by ecological receptors.  The vegetative matting will be
placed over steep slopes located along the stream channel
within Area A.


8.3  Soil RAA 3:  Soil/Clay (or clay equivalent) Cover

              Capital Cost:                             $740,000
              Annual O&M Cost:                          $21,000
              Soil RAA NPW:                             $1,100,000
       •       Time to Implement:                       Less than one year

Under Soil RAA 3, a soil/clay  (or clay equivalent)  cover will be placed over the contaminated soil exceeding
the lead action limit of 400 mg/Kg to limit the potential for erosion, infiltration and direct
contact by human and terrestrial ecological receptors.  The lead action limit is used as an indicator of the
extent of contamination in Area A which received ash and debris from the incinerator and open burning.  Other
COCs are associated with the ash/debris and remediating lead in Area A soil also remediates other COCs such
as 1,3,5-TNB, antimony, cadmium and manganese.   The cover will consist of 12 inches of compacted clay (or
clay equivalent), 6 inches of topsoil, and cover an area of approximately 7,400 square yards.  In areas where
loose, uncompacted ash material is situated on steep slopes, cover construction may not be feasible.
Depending on the specifics of the remedial design loose material may be excavated, debris removed, and spread
on top of the flat portion of Area A which is already affected  (Figure 8-1).  The cover will then be
constructed on the resulting soil pile.  Periodically, the cover will be visually inspected and patched when
needed.  This alternative also includes the same institutional controls, monitoring plan, and erosion control
measures included under Soil RAA 2.

8.4  Soil RAA 4:  Excavation and Off-Site Landfill Disposal

              Capital Cost:                              $4,600,000
              Annual O&M Cost:                           $14,000
              Soil RAA NPW:                              $4,800,000
       •       Time to Implement:                        Less than one year

Under Soil RAA 4, the contaminated soil exceeding the lead action limit of 400 mg/Kg will be excavated,

-------
tested for Resource Conservation and Recovery Act (RCRA) characteristics to determine if it is hazardous or
non-hazardous, then transported for disposal at a permitted landfill facility. Approximately 11,000 cubic
yards of contaminated soil will require excavation and disposal. The excavation area will be backfilled with
clean soil and revegetated. This alternative also includes the same institutional controls, monitoring plan,
and erosion control measures included under Soil RAA 2.

8.5 Soil RAA 5: In Situ Solidification/Stabilization

Capital Cost: $1,200,000
Annual O&M Cost: $16,000
Soil RAA NPW: $1,400,000
• Time to Implement: Less than one year

Under Soil RAA 5, the contaminated soil exceeding the lead action limit of 400 mg/Kg will be mixed in situ
with cement-based additives. The soil-cement mixture will set and form a solid, non-leaching matrix (similar
to a concrete mass). Then a soil/clay (or clay equivalent) cover will be constructed over the solidified
matrix and revegetated. Periodically, the cover will be visually inspected and patched as needed, and
leaching tests will be conducted on the solidified matrix. Prior to the in situ treatment, treatability
studies will be conducted to determine the appropriate mixture of solidifying agents and additives, the
appropriate setting time, and the anticipated treatment results. This alternative also includes the same
institutional controls, monitoring plan, and erosion control measures included under Soil RAA 2.

8.6 Soil RAA 6: Excavation and Soil Washing

Capital Cost: $2,800,000
Annual O&M Cost: $15,000
Soil RAA NPW: $2,900,000
• Time to Implement: Less than six months

Under Soil RAA 6, the contaminated soil exceeding the lead action limit of 400 mg/Kg will be excavated and
sent through an on-site treatment unit where it will undergo soil washing and soil leaching (i.e., acid
leaching) treatment. The excavation area will be backfilled with treated, clean soil. The recovered lead
will be reused at a lead smelter facility, and the washwater and acid will be sent for further treatment.
Prior to treatment, treatability studies will be conducted to determine the appropriate mixture of washing
agents and additives, and the anticipated treatment results. This alternative also includes the same
institutional controls, monitoring plan, and erosion control measures included under Soil RAA 2.

9.0 SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES

This section summarizes the comparative analysis of the RAAs developed for the contaminated soil in Area A
(OU III). The comparative analysis was based on the following nine evaluation criteria: overall protection
of human health and the environment; compliance with ARARs; long-term effectiveness/permanence; reduction of
toxicity, mobility, or volume through treatment; short-term effectiveness; implementability; cost; acceptance
by the Commonwealth of Virginia; and acceptance by the public. Table 9-1 provides definitions for several of
these evaluation criteria. Table 9-2summarizes the RAA evaluation using seven of the evaluation criteria.
The last two criteria, Commonwealth of Virginia acceptance and public acceptance are evaluated in Sections
9.8 and 9.9.

9.1 Overall Protection of Human Health and the Environment

Under Soil RAAs 1 and 2, no remediation actions will be implemented to remove, treat, or isolate the
contaminated soil. Human and ecological receptors may potentially have direct contact with Area A soil
contamination which is located at highly accessible depths (0 to 4 feet bgs). Soil RAA 2 provides some
restrictions on the amount of access that human receptors may have. These restrictions include institutional
controls that will limit future land use, long-term surface water monitoring that will monitor the migration
of contaminants from Area A, and erosion control measures that will mitigate the erosion of contaminated
soil. However, these restrictions will only mitigate, not completely eliminate, the potential for direct
human exposure and does not address potential exposure potential.

Like Soil RAAs 1 and 2, Soil RAA 3 allows the contaminated soil to remain untreated on site. However, Soil
RAA 3 includes a soil/clay (or clay equivalent) cover that will effectively prevent erosion and contaminant

-------
migration to Ballard Creek as well as isolate the contaminated soil from human and ecological receptors.
Thus, Soil RAA 3 will more effectively reduce potential human health and ecological risks compared to Soil
RAAs 1 and 2.  Soil RAA3 4, 5, and 6 will also effectively reduce potential risks to humans and ecological
receptors by treating and/or disposing of the contaminated soil.   However,  complete removal and treatment of
the contaminated soil is not necessary to provide adeguate protection to human health and the environment.

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                                       TABLE 9-1

                             GLOSSARY OF EVALUATION CRITERIA
                             SITE 12, BARRACKS ROAD LANDFILL
                           WPNSTA YORKTOWN, YORKTOWN, VIRGINIA

•       Overall Protection of Human Health and the Environment - addresses whether or not
       an alternative provides adequate protection and describes how risks posed through each
       pathway are eliminated,  reduced, or controlled through treatment engineering or institutional
       controls

•       Compliance with ARARs/TBCs - addresses whether or not an alternative will meet all of
       the applicable or relevant and appropriate requirements (ARARs) ,  other criteria to be
       considered (TBCs), or other Federal and state environmental statutes and/or provide grounds
       for invoking a waiver.

•       Long-term Effectiveness  and Permanence - refers to the magnitude of residual risk and
       the ability of an alternative to maintain reliable protection of human health and the
       environment over time once cleanup goals have been met.

•       Reduction of Toxicity, Mobililty,  or Volume Through Treatment -  refers to the
       anticipated performance of the treatment options that may be employed in an alternative.

•       Short-term Effectiveness - refers  to the speed with which the alternative achieves
       protection, as well as the remedys potential to create adverse impacts on human health and
       the environment that may result during the construction and implementation period.

•       Implementability - refers to the technical and administrative feasibility of an alternative,
       including the availability of materials; and services needed to implement the chosen
solution.

•       Cost - includes capital  and operation and maintenance costs.   For comparative purposes,
       provides present worth values.

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TABLE 9-2
Evaluation Criteria

OVERALL PROTECTIVENESS

6 Human Health
6 Environmental
COMPLIANCE WITH ARARs
Soil RAA 1
No Action
No protection.
Not applicable to soil.

Not applicable.
6 Action-Specific ARARs Not applicable.
ARARs

LONG-TERM EFFECTIVENESS AND PERFORMANCE
SUMMARY OF THE SOIL RAA EVALUATION
SITE 12, BARRACKS ROAD LANDFILL
WIPNSTA YORKTOWN, YORKTOWN, VIRGINIA
Low level of protection that
may not be adquate
considering the shallow depths
(0 to 4 feet bgs)at which
contaminants are located.

Low level of protection that
may not be adequate
considering the shallow depths
(0 to 4 feet bgs)at which
contaminants are located.
Not applicable to soil.

Not applicable.

Minimal risk reduction.
6 Need for 5-year Review Review will be required to
ensure adequate protection
human health and the
environment.
Review will be required to
ensure adequate protection of
human health and the
environment.
Significant risk reduction.
Review will be required to
ensure adquate protection of
human health and the
environment.
High level of protection.
High level of protection.
Significant risk reduction.
Review will not be required
for OU III. Will be required
for OU IV.
Soil RAA 5
In Situ Solidification/
Stabilization
Significant risk reduction. Significant risk reduction.
Review will be required to Review will not be required
ensure adequate protection of for OU III. Will be required
human health and the for OU IV.
environment.

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                                                                                                              TABLE  9-2  (Continued)
                                  Soil  RAA  1
   Evaluation Criteria            No Action

REDUCTION OF TOXICITY, MOBILITY,  OR VOLUME THROUGH TREATMENT

6  Treatment Process Used         No treatment  process.
       Soil RAA 2
Institutional Controls,
Monitoring, and Erosion
        Control
                                                                                                        SUMMARY  OF  THE SOIL RAA EVALUATION
                                                                                                          SITE 12,  BARRACKS ROAD LANDFILL
                                                                                                      WIPNSTA YORKTOWN,  YORKTOWN,  VIRGINIA
       Soil RAA 5
In Situ Solidification/
      Stabilization
       Soil RAA 6
Excavation and Soil Washing
                                 None.
6  Reduction of Toxicity,
   Mobility, or Volume
   Through Treatment
                                                                                                            Not  applicable-no treatment.
                                 Not  satisfied.
                                                                  Not satisfied.
SHORT-TERM EFFECTIVENESS

6  Community Protection
6  Worker Protection
                                                                  Potential risks to the
                                                                  community will be increased,
                                                                  but these risks will be minimal
                                                                  and easy to control.
                                          Potential risks to the          Potential risks to the           Potential risks to the           Potential risks to  the
                                          community will be increased,    community will be increased,     community will be increased,     community will be increased,
                                          but these risks will be minimal but these risks will be          but these risks will be          but these risks will  be
                                          and easy to control.             controlled.                      controlled.                       controlled.
6  Environmental Impact
6  Time Until Action is
   Complete
                                 Not  applicable.
                                                                                                      No  additional  environmental     No additional environmental
                                                                                                       impacts.                        impacts.
                                                                                                                                           No additional environmental
                                                                                                                                           impacts.

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                                                                                                              TABLE  9-2  (Continued)
   Evaluation Criteria

IMPLEMENTABILITY
                                  Soil  RAA  1
                                  No Action
       Soil RAA 2
Institutional Controls,
Monitoring, and Erosion
        Control
                                                                                                        SUMMARY  OF  THE SOIL RAA EVALUATION
                                                                                                          SITE 12,  BARRACKS ROAD LANDFILL
                                                                                                      WIPNSTA YORKTOWN,  YORKTOWN,  VIRGINIA
   Ability to Monitor
   Effectiveness
                                                                  Steep terrain will complicate
                                                                  construction.
                                                                  complicate construction.
                                                                                                         Steep terrain and loose,
                                                                                                         uncompacted ash material  will
                                                                                                         complicate construction.
                                                                                                         Debris and subsurface
                                                                                                         heterogeneities may inhibit the
                                                                                                         in situ mixing process.
                                                                                                                                     Services and eguipment
                                                                                                                                     should be readily available.
                                                                                                                                     Highly dependent on the
                                                                                                                                     availability of an off-site
                                                                                                                                     landfill.
                                                                                                Reguires  coordination with the
                                                                                                Station Public
                                                                                                Works/Planning  Department.
                                                                                                federal state acceptance of
                                                                                                off-site  facility  is  reguired;
                                                                                                coordination with  the Station
                                                                                                Public Works/Planning
                                                                                                Department.
                                                                  Coordination with the
                                                                  Department of Transportation
                                                                  for off-site transport of  soils;
Reguires coordination with the
Station Public
Works/Planning Department.
COST(Net Present Worth)

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Based on this information, Soil RAA 1 provides no protection of human health and the environment, Soil RAA 2
provides a low level of protection that may not be adequate considering the shallow depths at which the
contaminants are located, Soil RAA 3 provides an adequate level of protection, and Soil RAAs 4, 5, and 6
provide a hiqh level of protection that is not necessary.

9.2 Compliance with ARARs

Because chemical-specific ARARs have not been promulgated for contaminants in soil, an evaluation of
compliance with chemical-specific ARARs is not necessary. No action-specific or location-specific ARARs
apply to Soil RAAs 1 and 2. Action-specific and location-specific ARARs do apply to Soil RAAs 3, 4, 5, and
6; these alternatives can be designed to meet all applicable ARARs. The following action-specific ARARs (or
portions of these ARARs) apply: RCRA Subtitle C, National Ambient Air Quality Standards, Virginia Solid
Waste Management Regulations, Toxic Substance Control Act (TSCA) - PCB Spill Cleanup Policy, Virginia
Hazardous Waste Regulations, Landfill Closure and Post-Closure Care, Virginia Stormwater Management and
Erosion and Sediment Control Regulations, and Virginia Ambient Air Quality Standards.

9.3 Long-Term Effectiveness and Permanence

Soil RAA 1 does not provide long-term effectiveness and permanence. This is because Soil RAA 1 allows human
and ecological receptors to have unlimited exposure to the contaminated soil. Like Soil RAA 1, Soil RAA 2
allows the contaminated soil to remain untreated on site. However, Soil RAA 2 includes institutional
controls, long-term monitoring, and erosion control measures to manage the soil contaminants. Regardless, the
contaminants are located at such shallow, accessible depths (0 to 4 feet bgs) that Soil RAA 2 will only
provide limited effectiveness and permanence.

Soil RAAs 3, 4, 5, and 6, on the other hand, provide higher levels of effectiveness and permanence by either
eliminating or further mitigating the potential soil risks associated with Area A. The effectiveness of Soil
RAAs 3 and 5, however, is extremely dependent on the effectiveness of long-term maintenance of the soil/clay
(or clay equivalent) cover and/or the solidified matrix.

9.4 Reduction of Toxicity, Mobility, or Volume Through Treatment

Soil RAAs 1, 2, 3, and 4 do not involve treatment processes so these alternatives will not reduce toxicity,
mobility, or volume of the soil contamination through treatment, nor will these alternatives satisfy the
statutory preference for treatment. Soil RAAs 5 and 6 involve treatment processes so these alternatives will
satisfy the statutory preference for treatment. Under Soil RAA 5, the treatment process
(solidification/stabilization) will reduce the mobility of the soil contaminants. Under Soil RAA 6, the
treatment process (soil washing) will reduce the mobility, toxicity, and volume of the soil contaminants.

9.5 Short-Term Effectiveness

Implementation of Soil RAA 1 does not increase risks to the community or to workers because no actions will
be taken. Soil RAAs 2 and 3 may slightly increase risks during the periodic sampling events and during
construction of the rip rap and vegetative matting, but these risks will be minimal and easy to control.
Soil RAA 3 may further increase risks during construction of the soil/clay (or clay equivalent) cover, but
these risks will also be minimal and relatively easy to control. Soil RAAs 4, 5, and 6 will present the most
short-term risks because they involve extensive soil excavation and backfilling, activities. In addition,
Soil RAAs 5 and 6 include treatment processes, and Soil RAA 4 includes transportation of the contaminated
soil, which will necessitate extensive handling of the contaminated material.

9.6 Implementability

Soil RAA 1 is the most implementable alternative. Soil RAA 2 is the next most implementable alternative
because it only involves surface water sampling and construction of rip rap and vegetative matting. The
remaining RAAs (Soil RAAs 3, 4, 5, and 6) are not as easily implemented because they involve cover
construction, soil excavation and backfilling, transportation of contaminated materials, and/or treatment
processes. The implementability of all of the alternatives, with the exception of Soil RAA 1, will be
impacted by the steep terrain located along the stream channel at Area A. This will complicate the
construction of rip rap and vegetative matting and excavation/backfilling activities. Some steep areas may
be inaccessible to conventional construction equipment. In addition, construction and excavation activities
will be difficult in areas that contain loose, uncompacted ash material. Under Soil RAA 5, in situ soil
mixing may be inhibited by the debris that is located within Area A and by subsurface heterogenities.

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With the exception of Soil RAA 1, all of the alternatives will require extensive coordination with the
Station Environmental Directorate, Public Works/Planning Department.  Soil RAA 4 will also require
coordination with the Department of Transportation and Commonwealth and Federal acceptance of the off-site
disposal facility.  All required services, materials, and/or technoloqies should be readily available under
all six alternatives.

9.7  Cost

In terms of NPW, the no action alternative  (Soil RAA 1)  would be the least expensive RAA to implement,
followed by Soil RAA 2 ,  Soil RAA 3, Soil RAA 5, Soil RAA 6, and then Soil RAA 4. The estimated NPW values,
in increasing order, are

              $0 (Soil RAA 1:   No Action)
              $680,000 (Soil RAA 2:   Institutional Controls, Monitoring,  and Erosion Control)
              $1,100,000  (Soil RAA 3:   Soil/Clay [or clay equivalent]  Cover)
              $1,400,000  (Soil RAA 5:   In Situ Solidification/Stabilization)
              $2,900,000  (Soil RAA 6:   Excavation and Soil Washing)
              $4,800,000  (Soil RAA 4:   Excavation and Off-Site Landfill Disposal)

These costs do not include the cost associated with a long-term monitoring program for OU V. Assuming that a
minimum of nine existing wells, three newly installed wells and seven surface water/sediment locations will
be sampled semi-annually over a thirty year period, a net present worth cost of $1,174,000 was derived.  This
cost will be refined as a long-term monitoring work plan is developed by the Navy, USEPA Region III and the
Commonwealth of Virginia (see Appendix B).

9.8  Commonwealth Acceptance

The Commonwealth of Virginia concurs with the remedy selected for Site 12, namely:  Soil RAA 3 (Soil/Clay  [or
clay equivalent] Cover) for contaminated soil in Area A  (OU III); no action for the soils in Area B/C and
Wood Debris Area  (OU IV); and property use restrictions, along with long-term monitoring, for Site 12
groundwater and Ballard Creek surface water and sediments  (OU V).

9.9  Community Acceptance

The DoN solicited input from the public on the remedial action alternatives described in this ROD, and held a
public meeting to hear the community's concerns.  Based on comments received, the public appears to support
the selected remedy.  The public's questions and comments, and DoN's responses, are presented in the
Responsiveness Summary at the end of this ROD, and the transcript of the public meeting, is presented in
Appendix B.

10.0  THE SELECTED REMEDY

This section of the ROD presents the selected remedy for Site 12.  The following information is presented:  a
remedy description, which includes the rationale behind the remedy selection; the performance standards to be
attained at the conclusion of the remedy; and the costs estimated to implement the remedy.

10.1 Remedy Description

The selected remedy for Site 12 includes Soil RAA 3:  Soil/Clay (or clay equivalent) Cover for OU III, no
action for OU IV, and a long-term groundwater, surface water, and sediment monitoring program for OU V.
(Figure 8-1 depicts Soil RAA 3).  Thus, the selected remedies will include the following:

             OU III - Area A Soil

       •      Excavating  the soil and the removal of debris located on steep slopes,  spreading
              excavated soil over flat portions of Area A, and backfilling the excavated area with
              clean soil.

       •      Placing and compacting 12 inches of clay or a material with similar permeability
              over the resulting soil pile  (approximately 7,400 square yards).  Placing and
              compacting six inches of topsoil over the clay/clay equivalent material.

       •      Construction of erosion control along the  steep slopes located along the  stream

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              channel within Area A.

       •      Implementing land use restrictions in the Station Master Plan and long-term
              monitoring of surface water at Area A.

             OU IV - Area B/C, Wood/Debris Disposal Area Soils

       •      No Action


             OU V - Groundwater Ballard Creek Surface Water and Sediments

       •      Implementing property/aguifer use restrictions throughout Area A,  Area B/C and
              the Wood/Debris Disposal Area in the Station Master Plan to ensure that
              groundwater at Site 12 is not used as a drinkable source.

       •      Implementing long-term monitoring of groundwater from shallow and deep wells
              across the study area, and surface water and sediment from Ballard Creek and its
              tributaries.  The details of this monitoring program (e.g., sampling locations,
              freguency, and analyses) will be identified in a long-term monitoring work plan, a
              primary document in the FFA.

10.1.1 The Selection of Soil RAA 3:  Soil/Clay  (or clay eguivalent) Cover for OU III

Based on the results of the alternative evaluation, Soil RAA 3:  Soil/Clay  (or clay eguivalent) Cover was
selected as the remedy for the contaminated soil at Area A  (OU III) because it provides the most appropriate,
cost-effective level of protection considering the nature of the contamination.  Because the contaminated
soil is located at shallow, highly accessible depths  (from 0 to 4 feet bgs), a physical barrier to prevent
erosion and direct exposure is necessary.  A soil/clay  (or clay eguivalent) cover will provide such a
barrier, provided it is maintained over time, the cover will effectively isolate the contaminated soil.  Soil
RAAs 4, 5, and 6  (Excavation and Off-Site Disposal, In Situ Solidification/ Stabilization, and Excavation and
Soil Washing) may also prevent erosion and direct exposure by actively removing, treating, or disposing of
the contaminated soil.  However, these RAAs are not as easily implemented,  and/or do not provide in increase
with respect to cost benefit compared to the soil/clay  (or clay eguivalent) cover alternative.  Soil RAA 4
reguires excavation/transportation/backfilling of approximately 11,000 cubic yards of contaminated soil, Soil
RAA 5 reguires in situ mixing which may be impeded by subsurface obstructions and heterogenities, and Soil
RAA 6 reguires mobilization of an on-site soil washing system and excavation/treatment/backfilling of
approximately 11,000 cubic yards of soil.  Soil RAA 3 only reguires the construction of a 12 inch soil/clay
(or clay eguivalent) cover over approximately a 7,400 sguare yard area.  In addition, the costs estimated for
Soil RAAs 4, 5, and 6  ($4.8 million, $1.4 million, and $2.9 million,  respectively) exceed the cost estimated
for Soil RAA 3  ($1.1 million).

10.1.2   The Selection of the No Action Alternative for OU IV

RAAs were not proposed for Area B/C soil and Wood/Debris Disposal Area soil  (OU IV) because of the limited
risk to human health and ecological receptors by soil COCs in these areas.  As such, the No Action
Alternative was selected.

10.1.3   The Selection of Institutional Controls and a Long-Term Groundwater, Surface Water, and Sediment
         Monitoring Program for OU V

As explained earlier in this ROD, the risks associated with groundwater at  Site 12 are within acceptable
limits as long as people do not drink the groundwater.  Although COCs were  detected in Ballard Creek's
surface water and sediment, they do not pose unacceptable risks to human health or the environment.  The
levels of contamination are low, and treatment of the sediment would reguire dredging that would be more
harmful to the environment than the presence of the contamination.

For these reasons, the PRAP for this Site recommended that no remedial action be taken with respect to the
groundwater at Site 12 or the surface water and sediment of Ballard Creek.  The Proposed Plan did recommend,
however, a long-term monitoring program for the groundwater, surface water  and sediment.

In response to USEPA's comments on the PRAP, the original proposal was modified.  The remedy for Site 12
groundwater now includes institutional controls (i.e., land use restrictions) to ensure that the groundwater

-------
is not used as a drinking water source. In addition, the DoN will perform long-term monitoring of Site 12
groundwater and Ballard Creek's surface water and sediment. Long-term monitoring will help to ensure that
the groundwater guality and surface water/sediment guality do not further deteriorate. This monitoring
program will be implemented in addition to the long-term monitoring specified for Area A (OU III) under Soil
RAA 3. The OU V monitoring program will include periodic sampling and analysis of groundwater in the
Cornwallis Cave (shallow) and Yorktown-Eastover (deep) aguifers, surface water and sediment in Ballard Creek.
Fish tissue and/or sediment toxicity testing may also occur. The details of the program (e.g., sampling
locations, freguency, duration, and analyses) will be identified in a long-term monitoring work plan. If the
monitoring program indicates that groundwater, surface water, or sediment guality is deteriorating,
remediation of these media may be reconsidered. Results of long-term monitoring will be evaluated as part of
the five year review to determine whether the response action is protective of human health and the
environment, analyze newly promulgated or modified reguirements of Federal or Commonwealth of Virginia
environmental laws to determine if they are ARARs and potential changes to monitoring indicators.

10.2 Performance Standards

10.2.1 Soil/Clay (or clay eguivalent) Cover and Erosion Control Measures

The soil/clay (or clay eguivalent) cover and erosion control measures will be constructed for OU III
to the following performance standards.

The soil/clay (or clay eguivalent) cover will minimize erosion and potential infiltration of precipitation.
The cover will consist of 12 inches of compacted clay or a similar material which provides an in-place
permeability similar to 12 inches of compacted clay. Six inches of topsoil will be placed on top of the clay
or clay eguivalent to sustain a vegetative cover.

Erosion control measures may also include the construction of rip rap and the addition of clean fill material
lining the entire length of the Area A stream channel that discharges to Ballard Creek.

The soil/clay (or clay eguivalent) cover and erosion control measures described in RAA 3 are intended to
limit the potential for erosion of organic and inorganic contaminants detected in Area A to Ballard Creek.
RAA 3 will also prevent the direct contact of contaminated Area A soils by current human, terrestrial, and
aguatic receptors. The extent of the cover will be sufficient to cover contaminated soils containing lead
concentrations of 400 mg/Kg or greater. The extent of the cover will also address soil exhibiting PCB
contamination exceeding the TSCA-PCB Spill Cleanup Policy Clean Soil value of 1.0 mg/Kg total PCBs. The 400
mg/Kg lead value is an USEPA action limit for soil lead derived using the UBK model. Because elevated lead
levels are associated with the presence of ash and affected soils at Area A, this RL is protective of both
human health and aguatic and terrestrial ecological receptors. Table 10-1 presents COCs and corresponding RL
values for Area A soils which will be addressed by RAA 3.

Long-term monitoring and five year reviews will be conducted as part of RAA 3 (as per the NCP) to determine
that the remedy prevents erosion of soil-borne contaminants and precludes direct contact by humans and
ecological receptors. Five year reviews are intended to evaluate whether the response action remains
protective of public health and the environment. The review will consist of a review of documented
operations, maintenance of the site, review of long-term monitoring results, analysis of newly promulgated or
modified reguirements of Federal or Commonwealth of Virginia environmental laws to determine if they are
ARARs and possibly a site visit. A further objective of the five year review is to consider the scope of O&M
for the cover at Area A, the freguency of repairs, potential changes in monitoring indicators, costs and how
overall actions relate to protectiveness.

10.21 Long-Term Monitoring

Shallow and deeper groundwater, and Ballard Creek surface water and sediments (OU V) will be subjected to
long-term monitoring.

Long-term monitoring will be conducted to determine the potential impact of TCE in shallow groundwater on
deeper groundwater and the water guality of Ballard Creek. Groundwater monitoring will be conducted and will
reguire reviews of a minimum of every 5 years as per the NCP. Ballard Creek surface water and sediments will
be monitored as agreed to by the parties to determine temporal effects on the concentration of COCs. Fish
tissue and/or toxicity testing may also be considered as part of the surface water and sediment monitoring
effort.

Monitoring of groundwater and surface water will be conducted to assure that surface water concentrations of

-------
TCE in Ballard Creek proper do not exceed the Virginia Water Quality Standard for surface water of 807lg/L.
Again, because of the future land use restrictions associated with contamination in groundwater,  groundwater
will be monitored with reviews occurring at a minimum every 5 years as per the NCP.  Surface water and
sediment monitoring of Ballard Creek will be conducted as agreed to by the parties.  Table 10-2 presents
ecological COCs and trigger values pertinent to the long-term monitoring effort for OU V.  Exceedence of
trigger values could result in the reevaluation of the selected remedy.

-------
                                        TABLE 10-1
                              AREA A SOIL REMEDIATION LEVELS
                            SITE 12 - OPERABLE UNIT NUMBER III
                              NAVAL WEAPONS STATION YORKTOWN
                                     YORKTOWN, VIRGINIA
    Chemical of Concern

1,3,5-Trinitrobenzene


Antimony


Cadmium




Manganese


Lead




Notes:
Maximum Detected
 Concentration
    (mg/Kg)

      3.7
     28.5L
     25.7
    1,230
    9,100 (1)
  Human
Health RL
 (mg/Kg)
                            170
                             65
 3,000
                            400*
          Basis of Goal

Protection of Human Health/Current
land use scenario

Protection of Human Health/Current
land use scenario

Protection of Human Health/Current
land use scenario.  RAA 3 also
protects ecological receptors/Prevent
potential erosion to Ballard Creek

Protection of Human Health/Current
land use scenario

Protection of Human Health/Current
land use scenario.  RAA 3 also
protects ecological receptors/Prevent
potential erosion to Ballard Creek
 (1) Obtained from a shallow subsurface soil sample.
Human Health RLs derived using a current land use  (i.e., trespasser scenario) unless otherwise noted.
mg/Kg - milligrams per kilogram
* - Lead action level derived from UBK model.
RL - Remediation Level

-------
   Chemical of Concern

Trichloroethene
Trichloroethene
PAHs
PCBs
Cadmium
Manganese
Silver
Antimony
Beryllium

Notes:
                                               TABLE 10-2

                                   LONG-TERM MONITORING TRIGGER VALUES
                                    SITE 12 - OPERABLE UNIT NUMBER V
                                     NAVAL WEAPONS STATION YORKTOWN
                                           YORKTOWN, VIRGINIA
Medium of Concern

   Groundwater
  Surface Water
    Sediment
    Sediment
    Sediment
    Sediment
    Sediment
    Sediment
    Sediment
Trigger Value

 16,000 Ig/L
  807 Ig/L
     NA
     NA
     NA
     NA
     NA
     NA
     NA
           Basis

Risk/Beneficial Use Scenario
        VDEQ - WQC
            TBD
            TBD
            TBD
            TBD
            TBD
            TBD
            TBD
NA   =  Not Available
TBD  =  To be determined during the development of the long-term, monitoring work plan
VDEQ =  Virginia Department of Environmental Quality
WQC  =  Water Quality Criterion for the protection of human health at ICR = 1 x 10-04
PAHs =  Polynuclear Aromatic Hydrocarbons
PCBs -  Polychlorinated Biphenyls
ug/L =  micrograms per liter

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10.3 Estimated Costs

The following costs were estimated for the Soil RAA 3: Soil/Clay (or clay equivalent) Cover

• Capital Cost: $740,000 (includes cover and erosion control measures)
• Annual O&M Cost: $21,000 (includes 30 years of cover maintenance and
30 years of surface water monitoring at 4 locations)
Net Present Worth: $1,100,000

The following costs were estimated for the long-term monitoring program for OU V:

• Capital Cost: $30,300 (includes installation of 3 new wells)
• Annual O&M Cost: $74,400 (includes 30 years of semi-annual monitoring)
Net Present Worth: $1,174,000

The actual cost associated with the long-term monitoring program for OU V will be established in the
long-term monitoring work plan.

11.0 STATUTORY DETERMINATIONS

A selected remedy must satisfy the requirements of CERCLA, Section 121, including: protection of human
health and the environment; compliance with ARARs; cost effectiveness; utilization of permanent solutions and
alternative treatment technologies or resources recovery technologies to the maximum extent practicable; and
preference for treatment that reduces toxicity, mobility, or volume as a principal element (or provide an
explanation as to why this preference is not satisfied).

The evaluation of how the selected remedy for Site 12 satisfies these CERCLA requirements is presented below.

11.1 Protection of Human Health and the Environment

The selected remedy will provide overall protection of human health and the environment. Provided it is
adequately maintained, the soil/clay (or clay equivalent) cover will prevent human and ecological receptors
(with the exception of burrowing animals) from contacting the contaminated soil. Thus, the cover will
alleviate the potential erosion of soil-borne contaminants and potential human and ecological risks. The
alternative will provide additional protection by including institutional controls and long-term monitoring
(for both OU III and OU V). The institutional controls will restrict future land use at Site 12 further
mitigating the potential for direct exposure and potential risks. Similarly, the long-term monitoring
programs will provide a warning mechanism against contaminant concentrations that may increase to levels
above trigger concentrations. Thus, the monitoring programs will further mitigate the potential for direct
exposure and potential risks. Finally, the erosion control measures will impede the erosion of contaminants
from Area A. Thus, the potential for receptors located downstream of the site to contact eroded,
contaminated soil will be mitigated. The selected remedy will entail a review by the lead agency every five
years (as per the NCP) to ensure continued protection of human health and the environment.

11.2 Compliance with Applicable or Relevant and Appropriate Requirements (ARARs)

Because chemical-specific ARARs have not been promulgated for contaminants in soil, an evaluation of
compliance with chemicai-specific ARARs is not necessary. However, to-be-considered (TBC) risk-based
criteria were identified for contaminated soil. The selected remedy will comply with TBCs, which include the
USEPA lead action level of 400 mg/Kg. This action level was obtained from the Revised Soil Lead Guidance for
CERCLA Sites and Corrective Action Facilities (OSWER Directive 9355.4-12, July 14, 1994). It is a
non-enforceable contaminant level intended as a guideline for cleanup of lead in soil. The selected remedy
can also be designed to comply with all applicable action-specific and location-specific ARARs such as the
TSCA-PCB Spill Cleanup Policy (see Tables 11-1 and 11-2) .

11.3 Cost-Effectiveness

Capping of the lead-contaminated soil will provided a cost-effective remedy. Of the four RAAs that provide
adequate protection to human health and the environment (Soil/Clay [or clay equivalent] Cover, Excavation and
Off-Site Landfill Disposal; In Situ Solidification/Stabilization; and Excavation and Soil Washing), the
Soil/Clay (or clay equivalent) Cover is the least expensive alternative. The NPW is approximately $1,100,000
compared to $1,400,000, $2,900,000, and $4,800,000 for the other three alternatives. Therefore, the
Soil/Clay (or clay equivalent) Cover RAA is also the most cost-effective alternative.

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11.4  Utilization of Permanent Solutions and Alternative Treatment Technologies

The selected remedy will present a permanent solution for Site 12.   Provided they are adequately maintained
over time, the soil/clay (or clay equivalent) cover, erosion control and vegetative matting,  will present a
permanent, long-term solution for the contaminated soil at Site 12.  Provided they are enforced over time,
the institutional controls will also present a permanent, long-term solution for potential exposure to
contaminated soil.  Finally, the long-term monitoring program (including surface water monitoring under Soil
RAA 3,  and groundwater, Ballard Creek surface water, and sediment monitoring under the OU V monitoring
program)  will provide a permanent, long-term solution for evaluating contaminant levels over time.  The
selected remedy,  however, does not utilize alternative treatment technologies.

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                                             TABLE 11-1

                                    LOCATION-SPECIFIC ARARs AND TBCs
                                       FEASIBILITY STUDY, CTO-0311
                                     SITE 12, BARRACKS ROAD LANDFILL
                                    WPNSTA YORKTOWN, YORKTOWN, VIRGINIA
         Citation

FEDERAL/LOCATION-SPECIFIC
              Requirement
                                                                                                          ARAR/TBC Determination
        Comments
The Endangered Species Act of 1973
(16 USC 1531)  (40 CFR Part 502)
Requires action to conserve endangered and
threatened species and their critical habitats.
                                                                                                     Potentially applicable.
National Historic Preservation Act
(32 CFR Parts 229 and 229.4;
43 CFR Parts 107 and 171.1-5)
Groundwater Protection Strategy
Develops procedures for the protection of
archaeological resources.
EPA policy to protect groundwater for its
highest present or potential beneficial use.
strategy designates three categories of
groundwater:
   Class 1 - Special Ground Waters
   Class 2 - Current and Potential Sources of
             Drinking Water and Waters
             Having Other Beneficial Uses
   Class 3 - Groundwater Not a Potential
             Source of Drinking Water and of
             Limited Beneficial Use
                                                                                         The
                                                                                                     Applicable to any excavation on site.
                                                                                                     If archaeological resources are
                                                                                                     encountered during soil excavation,
                                                                                                     they must be reviewed by Federal
                                                                                                     and Commonwealth archaeologists.

                                                                                                     TBC requirement.
The Virginia Department of
Environmental Quality  (VDEQ) will
be notified of this project and the
Navy requests the involvement of the
Virginia Board of Game and Inland
Fisheries for determination of
endangered species or habitats.

Compliance can be met by submitting
copies of work plans to the Virginia
Department of Historic Resources
(VDHR).
Groundwater in the surficial aquifer is
considered a Class 3.
Executive Order 11990, Protection of       Action to minimize the destruction, loss or
Wetlands; 40 CFR 6, Appendix A; excluding  degradation of wetlands.
Sections 6(a)(2), 6(a)(4), 6(a)(6); 40 CFR
6.302
                                                         Relevant and appropriate.
                                                                                                                                             Wetlands are present on and near the
                                                                                                                                             site and could potentially be impacted
                                                                                                                                             by remedial response actions.
The Flood Plain Standard
40 CFR 270.14(b)(II)(iii)
                                           Information concerning the location of Site 12
                                           with respect to the 100 year flood plain.
                                                         Potentially applicable.

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TABLE 11-1 (Continued)

LOCATION-SPECIFIC ARARs AND TBCs
FEASIBILITY STUDY, CTO-0311
SITE 12, BARRACKS ROAD LANDFILL
WPNSTA YORKTOWN, YORKTOWN, VIRGINIA
Citation

STATE/LOCATION-SPECIFIC

Virginia Wetlands Regulations (VR 450-01-
0051)
Requirement
Regulates activities that impact wetlands.
Virginia Endangered Species Act and Virginia Action to conserve endangered species or
Board of Game and Inland Fisheries; Code of threatened species, including consultation with
Virginia Sections 29.1-563 et seg. and 29-100 the Virginia Department of Game and Inland
et seg. Fisheries, the Virginia Department of
Agriculture and Consumer Services, and the
Virginia Department of Conservation and
Recreation.
ARAR/TBC Determination
Potentially applicable to activities
that could impact site wetlands.

Potentially applicable.
Virginia Water Protection Permit Regulations
(VR 680-15-01)
Chesapeake Bay Preservation Act, Code of
Va. Sec. 10.1-2100 et seg., and the
Chesapeake Bay Preservation Area
Designation and Management Regulations
(CBPA Regulations) (VR 173-02-01)
Delineates the procedures and requirements to
be followed in connection with activities such
as dredging, filling, or discharging any
pollutant into, or adjacent to, surface waters, or
any activity which impacts the physical,
chemical, or biological properties of surface
water (including wetlands).

Requires that certain locally designated tidal
and nontidal wetlands, as well as other sensitive
land-disturbing activities, removal of
land areas, be subject to limitations regarding
vegetation, use of impervious cover, erosion
and sediment control, storm water management,
and other aspects of land use that may have
effects on water quality.
Potentially applicable.
Potentially applicable.
Comments
Activities that could impact wetlands
will comply with regulations.

The Commonwealth will be notified
of this project and the Navy request
determination of endangered species
or habitats from the Commonwealth.
Serve as the Commonwealth's
certification procedure related to the
U.S. Army Corps of Engineers °404
Permit.
The CBPA requirements are
administered by a local board.

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                                                 TABLE 11-2

                                 POTENTIAL ACTION-SPECIFIC ARARs AND TBCs
                                      SITE 12, BARRACKS ROAD LANDFILL
                                    WPNSTA YORKTOWN, YORKTOWN, VIRGINIA
          Citation

FEDERAL/ACTION-SPECIFIC
          Requirement
    ARAR/TBC Determination
        Comments
DOT Rules for Hazardous Materials Transport  Regulates the transport of hazardous waste
(49 CFR Parts 107 and 171.1-500)             materials including packaging, shipping, and
                                             placarding.
Resource Conservation and Recovery Act
(RCRA) Subtitle C
Regulates the treatment, storage, and disposal
of hazardous waste.
Applicable for any action requiring
off-site transportation of hazardous
materials.

Applicable to remedial actions
involving treatment, storage, or
disposal of hazardous waste.
Remedial actions may include off-site
treatment and disposal  (e.g., off-site
regeneration of activated carbon).

Remediation may involve treatment,
storage, or disposal of hazardous
waste.
       Identification and Listing of
       Hazardous Waste  (40 CFR Part 261)
Regulations concerning determination of
whether or not a waste is hazardous based on
characteristics or listing.
Applicable in determining waste
classification.
Some site contaminants may be
considered hazardous wastes.
       Treatment, Storage, and Disposal
       (TSD) of Hazardous Waste
       (40 CFR Parts 262-265, 266)

       Manifest Systems, Recordkeeping,
       and Reporting (40 CFR Part 264,
       Subpart E)

       Releases from Solid Waste
       Management Unites  (40 CFR Part
       264, Subpart F)

       Use and Management of Containers
       (40 CFR Part 264, Subpart I)
Regulates the treatment, storage, and disposal
of hazardous waste.
Regulates manifest systems related to
hazardous waste treatment, storage, and
disposal.

Regulates releases from solid waste
management units.
Regulates use and management of containers
being stored at all hazardous waste facilities.
Applicable in the event that wastes
on site are classified as hazardous.
Applicable to remedial actions
where hazardous waste is generated
or transported.

All solid waste management units on
site shall comply with requirements.
Applicable to containers stored on
site.
TSD activities related to hazardous
waste will comply with regulations.
 Remedial actions may include off-site
 disposal or treatment.
 Groundwater protection standards
 apply to solid waste management
 units.

 Remedial actions may generate
 containerized waste.  Investigation-
 derived waste  (IDW) is containerized.
National Emissions Standards for Hazardous
Air Pollutants  (NESHAPs)  (40 CFR Part 61)
Toxic Substance Control Act  (TSCA) - PCB
Spill Cleanup Policy  (40 CFR Part 761)
Standards promulgated under the Clean Air Act
for significant sources of hazardous pollutants,
such as vinyl chloride, benzene,
trichloroethylene, dichlorobenzene, asbestos,
and other hazardous substances.  Considered
for any source that has the potential to emit
10 tons of any hazardous air pollutant or
25 tons of a combination of hazardous air
pollutants per year.

Establishes the measure which EPA considers
to be adequate cleanup for PCB contaminated
sites.
Applicable to releases or potential
releases of hazardous pollutants.
Remedial actions may result in
release of hazardous air pollutants.
Applicable to Area A where PCBs
were detected in soil samples.
 To be used during remedial design to
 determine that air emissions from the
 treatment facility will not exceed air
 emission standards.
 TSCA clean soil value of 1.0 mg/Kg
 (ppm)  will be considered in the
 remedial design of the Area A cover

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TABLE 11-2 (Continued)
Citation

FEDERAL/ACTION-SPECIFIC (continued)
POTENTIAL ACTION-SPECIFIC ARARs AND TBCs
SITE 12, BARRACKS ROAD LANDFILL
WPNSTA YORKTOWN, YORKTOWN, VIRGINIA

Requirement
ARAR/TBC Determination
Comments
National Ambient Air Quality Standards
(NAAQS) (40 CFR 50)
Standards for the following six criteria pollutants:
particulates matter, sulfur dioxide; carbon
monoxide; ozone; nitrogen dioxide; and lead.
The attainment and maintenance of these
standards are required to protect the public health
and welfare.
TBC requirement.
TBC as treatment process could include
one of the six criteria.
STATE/ACTION-SPECIFIC
Virginia Solid Waste Management Regulations Regulates the disposal of solid wastes.
(VR 672-20-10)
Virginia Hazardous Waste Management
Regulations (VR 672-10-1)
Regulates the treatment, storage, and disposal of
hazardous waste.
Identification and Listing of Hazardous Regulations concerning determination of whether
Waste (VR 672-10-1, Part III) or not a waste is hazardous based on
characteristics or listing.
Releases from Solid Waste
Management Units (VR 672-10,
Part X, Section 10.5)

Use and Management of Containers
(VR 672-10, Part X, Section 10.8)
Landfill - Closure and Post-Closure
Care
Regulates release from solid waste management
units.
Regulates use and management of containers
being stored at all hazardous waste facilities.
Provides closure and post-closure requirements
for hazardous waste landfills.
Applicable for solid (nonhazardous)
waste.

Applicable to remedial actions
involving treatment, storage, or
disposal of hazardous waste.

Applicable in determining waste
classification.
All solid waste management units on
site shall comply with requirements.
Applicable to containers stored on
site.
May be relevant and appropriate to
the Area A landfill (lead-contaminated
soil). Applicable for hazardous waste
landfills.
Remedial actions could include off-site
disposal of nonhazardous waste.

Remediation may involve treatment,
storage, or disposal of hazardous waste.
Some site contaminants are considered
listed wastes.
Groundwater protection standards apply
to solid waste management units.
Remedial actions may generate
containerized waste. Investigation-
derived waste (IDW) is containerized.
Virginia Stormwater Management Regulations
(VR 215-02-00) and Virginia Erosion and
Sediment Control Regulations (VR 625-02-00)
Regulates stormwater management and erosion/
sedimentation control practices that must be
followed during land disturbing activities.
Applicable for remedial actions
involving land disturbing activities.
Activities during construction will
comply with the Virginia Storm Water
Management Program. A sediment and
erosion control plan will be submitted
to LANTDIV for approval.

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Virginia Water Quality Standards
 (VR 680-21-00)
Surface water quality standards based on water
use and criteria class of surface water.
Virginia Solid Waste Management Regulations  Regulates the disposal of solid wastes.
 (VR 672-20-10)
Applicable to remedial actions
requiring discharge to surface water.
                                                       Applicable for solid  (nonhazardous)
                                                       waste.
Will be considered an ARAR used to
determine the discharge limit from a
remedial treatment facility.

Remedial actions could include off-site
disposal of nonhazardous waste.

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11.5 Preference for Treatment as a Principal Element

The selected remedy does not satisfy the statutory preference for treatment as a principal element.  Treatment
technologies for the contaminated soil at Site 12 were evaluated and screened during the FS.   However,  these
technologies were considered unnecessary in order to provide adeguate protection to human health and the
environment.  Long-term monitoring of groundwater and restrictions of future property use will ensure the
protection of human health and ecological receptors at Site 12.   Covering the contaminated soil with a
soil/clay (or clay eguivalent)  cover will prevent erosion of soil-borne contaminants and direct contact by
both human and ecological receptors to contamination at a reasonable cost.  In addition, vegetative matting
will prevent further erosion of contaminated Area A soil.

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RESPONSIVENESS SUMMARY

The Final Proposed Remedial Action Plan (June 1996) originally addressed two OUs: OU III - Area A soil; and
OU IV - Area B/C soil, Wood/Debris Disposal Area soil, and Ballard Creek surface water and sediment.

The preferred alternative for OU III was to construct a soil/clay (or clay equivalent) cover over lead-
contaminated soil at Area A. A long-term monitoring program was proposed for OU IV, the details of which
would be identified in a Long-Term Monitoring Work Plan. Long-term monitoring was recommended to ensure that
further deterioration of groundwater quality and Ballard Creek would not occur.

In response to comments from USEPA Region III, groundwater and Ballard Creek surface water and sediment
(which could potentially be affected by groundwater) were addressed as an OU (OU V) separate from Area B/C
soil and Wood/Debris Disposal Area soil (OU IV). As such, restrictions on future land use associated with
contaminated groundwater could be instituted to ensure that groundwater is not used as a drinking water
source. These changes were discussed at the July 26, 1996 public meeting (pages 41 through 43 of the
transcript provided in Appendix B).

In this ROD, Site 12 has been subdivided into three OUs. Site 12 OUs include:

OU III - Area A soil;

OU IV - Area B/C and Wood/Debris Disposal Area Soils and;

OU V - Groundwater, Ballard Creek Surface Water and Sediments.

No action is specified for OU IV and groundwater use restrictions, along with long-term monitoring is
specified for OU V. Under the long-term monitoring program specified for OU V groundwater will be monitored
with reviews occurring at a minimum of every 5 years as per the NCP. A review every five years as per the
NCP is required because future use of the property at Site 12 will be restricted because of contamination
that will remain on site in shallow groundwater. Surface water and sediments in Ballard Creek will be
monitored as agreed to by the parties. The details of the long-term monitoring program will be established
during the development of a long-term monitoring work plan, a primary document under the WPNSTA Yorktown FFA.

The selected remedy for OU III is the placement of a soil/clay (or clay equivalent) cover over contaminated
Area A soils. This remedy will prevent potential migration of contaminants via erosion to Ballard Creek and
will preclude direct contact of soil-borne contaminants by potential human and ecological receptors. The use
of clay or some material of similar permeability will also limit the potential downward movement of
soil-borne contaminants by limiting infiltration of precipitation.

Based on comments received from the audience at the Public Meeting July 26, 1996, the public appears to
support the aforementioned alternative. No written comments were received during the 45 day public comment
period.

The transcript of the Public Meeting is provided in Appendix C.

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                                  APPENDIX A

                   EXTENT OF GROUNDWATER CONTAMINATION

                       FIGURES A.I THROUGH A.8

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APPENDIX B

REMEDIAL ACTION ALTERNATIVES FOR GROUNDWATER

DEVELOPMENT OF REMEDIAL ACTION ALTERNATIVES FOR GROUNDWATER

If long-term monitoring of groundwater, surface water, and sediment across the entire Site 12 study area
indicates an increase in contaminant levels, a contingency plan involving active remediation may be
implemented for these media. Most likely, remediation of TCE-contaminated shallow groundwater will occur
since it is believed to be the source of surface water and sediment contamination. For contingency purposes,
three remedial action alternatives (RAAs) have been developed for groundwater:

• Pump and Treat
• In-Well Aeration
• Air Sparging and Soil Vapor Extraction

All three alternatives include long-term groundwater, surface water, and sediment monitoring and
assumptions about sampling locations, freguency, and analyses were made for cost estimating purposes only.
Table F-l presents a cost for the long-term monitoring program alone, and Figure F-l presents the assumed
sampling locations.

The following subsections present conceptual system designs for the three groundwater alternatives.

Pump and Treat

Under the pump and treat alternative, groundwater will be collected by extraction wells, transported to an
on-site treatment plant for VOC removal, then discharged to an on-site drainage way that eventually flows
into Ballard Creek.

Since pump tests have never been conducted at Site 12 or in the industrial area, there is no conclusive way
to determine the pumping rate and radius of influence for an extraction well in these locations. In lieu of
a pump test, the pumping rate and radius of influence were estimated based on slug test data, the site
geology, and the site hydrogeology. The pumping rate was estimated to be 5 gpm and the radius of influence
was estimated to be 150 feet. These estimates were made to assist in developing a conceptual system layout
and cost estimate. The estimations were not intended to be used as design parameters.

Based on the estimated radius of influence and pumping rate, 11 extraction wells will be installed to collect
groundwater from the surficial aguifer as shown in Figure F-2. Five of the wells will be arranged in a
downgradient row to contain the plume and provide a barrier against contaminant migration into Ballard Creek.
The other wells will be arranged to extract and the treat the "hot" portions of the plume. Each extraction
well will be screened near the confining unit, approximately 50 feet bgs.

After being extracted, the groundwater will be transported by pipeline to an on-site treatment plant. At the
treatment plant, the groundwater will undergo suspended solids and metals removal via neutralization,
precipitation, flocculation, sedimentation, and filtration units, and VOC treatment via a low profile air
stripper. After receiving treatment, groundwater will be discharged to the Site 12 stream channel that runs
through Area A and discharges into Ballard Creek.

Table F-2 presents a cost estimate for the pump and treat alternative. For cost estimating purposes, 30
years of system operation were assumed. The cost estimate also includes the proposed monitoring plan for
surface water, sediment, and groundwater.

In-Well Aeration

In-well aeration is a type of air sparging in which air is injected into a well creating an in-well air-lift
pump effect. This pump effect causes the groundwater to flow in a circulation pattern: into the bottom of
the well and out of the top of the well. As the groundwater circulates through the well, the injected air
stream strips volatiles. (As a result, in-well aeration is often referred to as in- well air stripping.) The
volatiles are captured at the top of the well and treated via a carbon adsorption unit.

The in-well aeration system for Site 12 and the Industrial Area will contain 20 aeration wells with
overlapping radii of influence as shown in Figure F-3. The approximate radius of influence for each well has
been estimated to be 75 feet. This estimate, made by a technology vendor, was based on site-specific

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geologic and hydrogeologic parameters. Eight of the wells will be arranged in a downgradient row to contain
the plume and provide a barrier against contaminant migration into Ballard Creek. The other wells will be
arranged to treat "hot" portions of the plume.

A separate vacuum pump, knockout tank, and carbon adsorption unit will be located near the opening of each
aeration well. The knockout tank will remove any liquids that may have traveled up the well (the amount of
knockout liguid will be minimal) and the carbon adsorption unit will treat off-gases that were stripped
within the well. Treated vapors from the carbon adsorption unit will be discharged to the atmosphere.

Because in-well aeration is a relatively new and innovative technology, a field pilot test is recommended
prior to initiating the system design. The pilot test will determine the loss of efficiency over time as a
result of inorganics precipitation and oxidation on the well screen, the radius of influence of the aeration
wells under various heads of injection air pressure, the rate of off-gas organic contaminant removal via
carbon adsorption, and carbon breakthrough times.

Table F-3 presents a cost estimate for the in-well aeration alternative. The cost estimate also includes the
proposed monitoring plan for surface water, sediment, and groundwater.

Air Sparging and Soil Vapor Extraction

Air sparging involves the injection of air into a well that is installed to the base of the contaminated
aguifer. The injected air exists through the well screen and moves outward and upward through the saturated
zone. As the air moves through the aguifer, it volatilizes dissolved contaminants and enhances natural
subsurface biodegradation. The volatilized contaminants may then be captured in the vadose zone by an SVE
well and treated via vapor-phase activated carbon.

The air sparging/SVE system for Site 12 and the Industrial Area will contain 38 air injection wells and 20
soil vapor extraction wells that are positioned to have overlapping radii of influence as shown in Figure
F-4. Technology vendors indicate that the radius of influence for an air injection well is approximately 1 to
1.5 times the submerged depth of the well [VISITT (IT Corporation), July 1994]. At Site 12 and in the
Industrial Area, this radius of influence would be approximately 20 to 30 feet (based on an average
submerged depth of 20 feet). For the conceptual layout, the radius of influence for an SVE well was assumed
to be 50 feet based on a vendor guote.

Volatilized TCE that is captured by the SVE wells will be sent to an on-site treatment plant where it will
undergo carbon absorption treatment. The treatment plant will also contain the necessary air and vacuum
blowers and vapor-water separation unit.

Because air sparging and SVE are relatively new and innovative technologies, a field pilot test is
recommended prior to initiating the system design. The pilot test will determine the loss of efficiency over
time as a result of inorganics precipitation and oxidation on the well screen, the radius of influence of the
air injection and SVE wells under various heads of pressure, the rate of off-gas organic contaminant removal
via carbon adsorption, and carbon breakthrough times. The field pilot test will also determine the off-gas
(i.e., untreated volatilized contaminants) concentrations that can be expected. If these concentrations are
low, SVE wells and off-gas treatment may not be necessary and the cost of this alternative will decrease.

Table F-4 presents a cost estimate for the air sparging/SVE alternative. The cost estimate also includes the
proposed monitoring plan for surface water, sediment, and groundwater.

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                                                           APPENDIX C
                                              PUBLIC MEETING MINUTES
    
                                                           2

 1                      MR. BLACK:  This is Rich Hoff from

 2   Baker Environmental.   He's going to give us a pitch

 3   on the public meeting,  Site 12 - Barracks Road

 4   Landfill.

 5                   MR.  HOFF:    Thanks, Tom.

 6                   Tonight we're here to present the

 7   PRAP for the Site 12  - Barracks Road Landfill.  And

 8   as part of the public comment period,  a meeting is

 9   tendered and the public was given the opportunity to

10   go over the Proposed Remedial Action and make

11   comments before the report becomes final.

12                      The public meeting tonight will

13   present a Site 12 overview; a summary of previous

14   investigations; Remedial Investigation results;

15   feasibility study,  and evaluation of alternatives;

16   the Proposed Remedial Action Plan, and the

17   modifications that have been made to the Remedial

18   Action decision; and then we'll take any guestions

19   that you-all may have.

20                      As a general  overview of Site 12,

21   the expanded study area is approximately 92 acres.

22   It's located near the industrial area of Weapons

23   Station, just to the  northeast of the industrial area

24   between Barracks Road and Ballard Creek.   Site 12

25   Proper contains three general areas; and those are
                                      FOX REPORTING
                  21 Michael's Woods  Drive, Hampton, Virginia  23666
                                      (804) 827-7843

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 1        Area A, Area B/C,  and the Wood/Debris  Disposal Area.

 2                   The first area we'd like to talk

 3   about is Area A.  Area A is located in the northeast

 4   area of the industrial area:  Incinerators that

 5   burned dunnage or waste materials from ships; and

 6   also open burning was conducted in this Area A, and

 7   ash was disposed of in this area.

 8                   Area B/C is located adjacent to the

 9   access road leading to Area A.  It is the furthest to

10   the northeast of any of the areas at Site 12.  And in

11   general you have disposal materials, a lot of scrap

12   wood, pilings,  banding,  containers,  et cetera.

13                      The Wood/Debris  Disposal Area is

14   somewhat central between Areas A and Areas B/C.  It

15   primarily disposed of lumber,  wooden pallets, but

16   there are other types of debris that are noticeable

17   throughout the Wood/Debris Disposal Area; metal

18   bandings, I believe rail lines,  disposed of rail

19   lines.

20                   And this material, by understanding

21    the site history and talking with people at the

22    Station, and evaluating it visually, appears to have

23    been stacked and pushed back over the ravine and then

24    covered with soil, at least the front part thereof.

25                   There have been several
                                      FOX REPORTING
                  21 Michael's Woods Drive, Hampton, Virginia  23666
                                      (804 )  827-7843

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 1    investigations conducted at Site 12,  and at all the

 2    sites at Weapons Station Yorktown.   They start with

 3    the Initial Assessment Study that was conducted in

 4    1984, and Interim RI that was conducted in the time

 5    frame of 1986 to  1989.

 6                   The Round One Remedial

 7    Investigation, which was the first project that Baker

 8    undertook under the RI program;  Roy F.  Weston was the

 9    subcontractor that did the field work for it,  and the

10    Round One report writing; a Habitat Evaluation that

11    was conducted by Baker in 1994;  and the Round Two

12    Remedial Investigation and subseguent investigations

13    running from 1994 through 1996.

14                      We'd  like  to go  over the Round One

15    and the Round Two Investigations tonight, because

16    those data are primarily the data that form the basis

17    of the decision-making at Site 12.

18                      The Round  One  Investigation was

19    conducted in 1992.  They investigated surface soils,

20    subsurface soils, groundwater, surface water,  and

21    sediment of Ballard Creek.

22                   As part of the Round One RI,  there

23    was no risk assessment performed, but the data was

24    summarized, and we do have some  of the analytical

25    data to present on the next few  figures.
                                      FOX REPORTING
                  21 Michael's Woods Drive, Hampton, Virginia  23666

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(804)  827-7843

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 1                   This figure I think we've seen

 2   before,  either at RAB meetings or at V-TAC meetings

 3   for Site 12.   It presents the organic data and the

 4   most pertinent organic constituents that were

 5   detected during the Round One Investigation,  and the

 6   investigation as it pertains to surface soils.

 7                      The abbreviation  stands for

 8   noncarcinogenic and carcinogenic polynuclear

 9   aeromatic hydrocarbons,  or PAH's, and they've been

10   totaled here, just to cut down on the volume that we

11   would otherwise be presenting on this figure.

12                   As you can use, most of the surface

13   soil samples, and a lot of the investigation centered

14   around the incinerator and the back side of the

15   incinerator,  which is considered Area A.

16                   And we have hits of PAH's that range

17   from 10 ppm's of noncarcinogenic PAH's, to as high as

18   roughly 7.9 or 8 ppm carcinogenic PAH's detected in

19   these samples.

20                   This overhead presents the inorganic

21   results.  And again,  we cut this back.  I believe

22   that this overhead was first displayed during a RAB

23   meeting for Site 12,  and we were trying to evaluate

24   the inorganic data with respect to the disposed ash

25   at Area A; and we were looking for a fingerprint at
                                      FOX REPORTING
                  21 Michael's Woods Drive, Hampton, Virginia 23666

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(804)  827-7843

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                                                              6

 1   the time,  so this figure focuses on the occurrence of

 2   lead and cooper.

 3                   And as you can see, we have some

 4   fairly high concentrations of lead detected in

 5   certain samples,  1200 ppm at 12S12, located on the

 6   ravine behind the incinerator.  Lead at 678 at 12S10,

 7   again behind the incinerator.

 8                   This in the groundwater data that we

 9   collected during the Round One RI,  and the primary

10   constituents detected in the groundwater were

11   volatile organic compounds, trichloroethene, and some

12   of its degradation products, 1-2 DCA,  DCE.  We see

13   relatively low levels throughout the area.  12GW01

14   being the highest location where TCE's detected at 55

15   micrograms per liter.

16                   But this was not unlike a lot of the

17   other sites that we've investigated at Weapons

18   Station Yorktown where you find a little bit of TCE's

19   throughout study areas.  And an we evaluated this

20   data, we felt fairly confident that we were in a

21   situation that was similar to those sites that we

22   have previously investigated.  This changes as part

23   of the Round Two investigation.

24                   This particular overhead presents

25   the inorganics detected in groundwater, both total
                                      FOX REPORTING
                  21 Michael's Woods Drive, Hampton, Virginia  23666

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(804)  827-7843

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 1   and dissolved.   And the interesting thing to note

 2   here is that lead is detected at relatively low

 3   levels in the total, but not in the dissolved

 4   groundwater samples.  And this is important because

 5   we saw the lead detected at relatively high levels in

 6   the surface soil at Area A, yet the groundwater

 7   samples really don't exhibit high concentrations of

 8   lead.   But you do find the constituents barium,

 9   copper, manganese,  and zinc, the typical actors that

10   we encounter at Weapons Station Yorktown.

11                   Surface water was also sampled an

12   part of the Round One Investigation,  and surface

13   water at Site 12 can be divided into two distinct

14   types:  Ballard Creek, which we believe, and the Navy

15   believes,  is an established waterway; and

16   intermittent streams that are formed by the ravine

17   and at times do have water, but at timen are dry.

18                   We sampled the intermittent stream

19   coming from the Area A portion of Site 12,  and

20   downstream thereof; and Ballard Creek as part of

21   Round One.  And you can see that we get relatively

22   low levels of TCE's in locations in Ballard Creek, as

23   well as the intermittent streams.

24                   Inorganics were also analyzed for

25   surface waters, and it's not unusual that we would
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 1   find the same actors.   We have lead detected in Area

 2   A intermittent stream;  a little bit of lead detected

 3   in the up-gradient location at 42

 4   milligrams/kilogram,  but no real pattern,  or

 5   discernible pattern,  specifically of lead occurring

 6   in the creek proper.

 7                   So as we evaluate this data, at

 8   least as part of the Round One Investigation,  it

 9   doesn't appear that Area A is a large contributor of

10   lead; at least at this time,  to the surface water

11   features,  which in Ballard Creek and its intermittent

12   streams.

13                   This overhead presents the results

14   of sediments.  Not surprisingly, we see the PAH's in

15   the sediments downstream of Area A in the

16   intermittent streams,  and PAH's sporadically

17   throughout Ballard Creek.  Relatively low levels.

18   Finally, the inorganics in sediment.

19   Again, you do have the detections of lead, a little

20   bit of mercury in the intermittent stream

21   downgradient of Area A.  You also have a little bit

22   of lead occurring in Ballard Creek, but no real

23   discernible, statistically discernible, pattern of

24   contamination.  And by that,  what would be nice to

25   see,  would be -- you know that you have lead in soils
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 1   in Area A; and we know that based on the nature of

 2   Site 12, this area is an area that is subject to

 3   erosion.  We would expect to see then,  a trend of

 4   lead or some other inorganic constituents as a

 5   fingerprint in the ravine and intermittent streams

 6   leading to Ballard Creek, and then hopefully

 7   downgradient of the confluence of Ballard Creek-and

 8   intermittent streams coming from Area A.  We would be

 9   able to see lead sort of winnowimg its way out along

10   the creek.  And again,  we really don't get that from

11   the Round One data.

12                   Based on this data,  work plans were

13   produced for a Round Two Remedial Investigation.  The

14   primary purpose of the Round Two Remedial

15   Investigation was to collect additional data to fill

16   the data gaps to conduct a baseline risk assessment,

17   both human health and an ecological risk assessment

18   for Site 12.

19                   An a result, we collected additional

20   soil samples, groundwater samples, surface water

21   samples, sediment samples, and in this particular

22   investigationt biota.  By biota, I mean benthic

23   results from sediment,  as well as fish population

24   counts from locations along Ballard Creek Proper.

25   An we're going to go through the figures that
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                                                           10
 1  present the data for Round Two in the same fashion as

 2  we did for Round One.

 3                   We collected additional surface soil

 4   samples,  particularly in Area A,  because of the high

 5   hits of lead.   And this figure was put together

 6   subseguent to the Round Two Investigation when we

 7   confirmed the results of the Round One and observed

 8   that lead was detected at levels in the thousands of

 9   parts per million in surface soils at certain

10   locations in Area A — and again,  they seem to

11   coincide with the ravine behind the incinerator where

12   we know ash was disposed of.

13                   Some of these data points were also

14    selected -- you'll notice an NA on the figure, this

15    was not analyzed, because what we were doing was

16    filling a data gap for the purpose of the Feasibility

17    Study during this particular phase of the

18    investigation.  And in areas where you see NA, the

19    shallows, this location was taken at depth to confirm

20    a surface soil hit of lead that was detected in

21    either the Round One or the Round Two.

22                   You can see the lead in relatively

23    high in certain locations, 12S62, 7,500 ppm,  and

24    9,100 ppm in the two to four foot sample.  And this

25    occurs throughout.  Exceedences of the 400 milligram
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                                                                 11
 1    per kilogram Human Health Action Level derived from

 2    the IUBK model,  both in the shallow samples,  as well

 3    as some of the deeper locations.

 4                   This particular overhead presents

 5    groundwater data for TCE.   After the Round One

 6    Investigation, and during the Round Two

 7    Investigation, we were installing hydropunches, and

 8    the hydropunches were being installed to optimize the

 9    placement of additional monitoring wells.

10                   When we did this, we ran into a high

11    hit of TCE in an area that was somewhat unexpected,

12    off of the corner of Building 4 and 5 of the

13    industrial area.  We had hydropunch hits and

14    groundwater detections of 800 parts per billion of

15    TCE,  and its breakdown products, 1-2 dichlorethane

16    were also detected.

17                   This was the first time we really

18    ran into any concentrations this high at a site at

19    Weapons Station, and it sort of surprised us because

20    we were not expecting to find it in that area.

21                   If you remember from the Round One

22    Investigation, we only found it at 55 ppm,  and I

23    believe that was at 12GW01, which is located in the

24    northernmost portion of the study area.

25                    We talked to the folks at the
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 1    Station and found that there was an underground

 2    storage tank that was located off the back side of

 3    Building 5, that  had been pulled a few years prior to

 4    our Round Two Investigation, and there was a

 5    monitoring well in place from that investigation.

 6                    So we resampled that particular

 7    monitoring well, USTMW04,  and built off of those

 8    results to produce a groundwater monitoring network

 9    that you see here.  But because we had detected TCE

10    in this area of the study area, we also investigated

11    the central portion of the industrial area where

12    another UST had existed until a few years ago,  and we

13    found the same type of situation.  We installed

14    hydropunches, got positive results, and then

15    installed wells.

16                   And in this area, we had

17    concentrations as high as 1300 micrograms per liter

18    in groundwater samples.  Building out from that, at

19    12HP18, we have a downgradient hit of 1700 micrograms

20    per liter.

21                   It's interesting when you look at

22    the topography out here and note how the surface

23    falls away-behind the industrial area toward Ballard

24    Creek,  and the ravine joins in and forms intermittent

25    streams that feed Ballard Creek.  You really get a
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                                                           13
 1    feel for how the topography plays into the movement

 2    of contaminants at this location.

 3                   We also had a site screening area

 4    that we were investigating simultaneously at Site 12

 5    that had some high hits of TCE in an intermittent

 6    stream adjacent to it.  And in our search for what

 7    might be the source of that TCE,  we sampled a seed

 8    location in a location northwest  of SSA15,  and behind

 9    the industrial area,  downgradient of our TCE plume,

10    where two ravines connect and meet.  And it's likely

11    that during rain events and during wet periods,  this

12    is probably a fairly substantial  area of-run-off.

13    But when we went out and sampled  it,  it was fairly

14    dry.  In fact, we had to reach up under some tree

15    roots and whatever to even collect a sample,  so it

16    was a depressed  area.

17                   It's somewhat a point of contention

18    between the Navy and the regulatory agencies as to

19    what type of sample that is.  Is  it a surface water

20    sample or is that a groundwater sample?  The Navy

21    contends by the nature of the sample,  it's more

22    likely a groundwater sample than  it is a surface

23    water sample because it's not really an established

24    water body in this particular area.

25                   Down further where these two
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                                                           14
 1    intermittent streams meet,  they form a more

 2    substantial water body which joins up with Ballard

 3    Creek Proper.

 4                   But as we were contouring the TCE

 5    and groundwater,  we saw this particular location fits

 6    in very nicely with the contouring of the data that

 7    was done for the groundwater samples.  And it really

 8    fits in nicely with the topography; although this

 9    figure doesn't really show it,  in that it appears

10    that the former UST that was located between

11    Buildings 3 and 4, released TCE to the groundwater.

12                   And incidentally,  when we sampled

13    this particular location,  we were looking for what we

14    would call a DNAPL, or the presence of a continuing

15    source of contamination to groundwater.  We were

16    doing this by visual observation of the material we

17    were taking from the bore hole, and also screening by

18    KNEW, and we sent a sample off for laboratory

19    analysis, and no TCE and no real DNAPL was observed

20    in the location of the former UST.

21                   Nonetheless, it appears we have two

22    distinct plumes of TCE in the Cornwallis Cave Aguifer

23    at Site 12.  Between the Cornwallis Cave Aguifer and

24    the Upper Yorktown Aguifer, there's a Yorktown

25    Confining Unit, which is fairly thick, an area that's
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                                                           15
 1    twenty feet thicker and geophysical evaluation of that

 2    material proves that the conductivity through it is

 3    fairly limited.

 4                   Subseguently the data for the

 5    Yorktown,  Upper Yorktown Confining Unit,  indicates

 6    that no TCE has made its way yet through that

 7    particular unit and is currently affecting the

 8    underlying aguifer.  So the contours you're seeing

 9    right here are for the Cornwallis Cave Aguifer.

10                   According to USGS, and looking at

11    the topography, it's very likely that the Cornwallis

12    Cave Aguifer discharges to Ballard Creek in some way

13    along the stretch of Ballard Creek Proper,  behind the

14    industrial area,  and that could be either through

15    areas of seeping,  that are really not observable

16    unless you were to be out there after a rain event

17    and witness the groundwater seeping along an area;

18    and it can also be through these intermittent ditches

19    and ravines.

20                   And that data is supported by this

21    particular seep sample where we have the highest hit,

22    at least to date,  of TCE of 3,300 micrograms per

23    liter.

24                   This particular overhead in a

25   compilation of the surface water data in Ballard
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 1    Creek and the tributaries in the expanded Site 12

 2    area.  At 12SW22,  we have no detected concentrations

 3    of volatiles in the surface water samples.   That's

 4    the furthest upgradient location along Ballard Creek.

 5                   As  you move down Ballard Creek, you

 6    see that there are intermittent hits and non-detected

 7    both in Ballard Creek and in the intermittent

 8    streams.  So it appears that the groundwater is

 9    likely, in certain areas in the ravines and along

10    Ballard Creek Proper, having TCE migrate and thusly

11    affect the water body.

12                   But again, I'd like to stress that

13    the levels are relatively low,  .7J at SW/SD17;

14    relatively low on the back side of Area A after the

15    confluence of the  intermittent stream.

16                   The highest detected

17    concentration -- and again, this was what took us

18    down the line to  sampling the seep in the vicinity of

19    SSA15, was 15SW10  where we had a hit of 340

20    micrograms per liter.  It's sort of interesting that

21    this particular sample was sampled twice; once I

22    believe in 1995, Dave, during the SSA Investigation?

23                   MR. DAVIS: Late '94.

24                   MR. HOFF: Late '94, early '95; and

25    again in early 1996, and the concentrations were very
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 1    similar,  300 to 400 micrograms per liter.   The data

 2    suggests  then that TCE's in this particular seep,  or

 3    in the groundwater regime on the backside  of SSA15

 4    associated with the industrial area,  may be seeping

 5    to this particular water feature and affecting the

 6    water guality; but it's  very guickly diluted out by

 7    the time  it reaches Ballard Creek.

 8                      Of  the things that were  accomplished

 9    during the Round Two Remedial Investigation were the

10    geophysical surveys; and more importantly,  the human

11    health risk assessments, and the ecological risk

12    assessment.

13                   The geophysical survey was  conducted

14    to better define areas,  or extent of the former

15    disposal  areas.  During  the Round One Investigation,

16    Weston had done some geophysical interpretation of

17    the waste disposal areas,  and they had left hatch

18    lines for us to fill in  as part of the Round Two.

19    The geophysics were conducted, therefore,  to fill in

20    those hatched areas and  give us a better indication

21    of the extent of the site.

22                      The complications with that  is  that,

23    as you begin to try to define the extent of these

24    sites, and the subareas  of Site 12,  you very guickly

25    run into  the wooded areas;  you run into the existence
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 1    of roads,  fences.   These are all features that

 2    greatly affect the results of the geophysics.   So the

 3    geophysics give us some indication of the extent of

 4    these areas,  but I think a far better indication is

 5    using a test pit where you can actually dig into the

 6    material and not only determine the extent of the

 7    disposed area vertically and horizontally, but also

 8    get an idea of the nature of what's in there.

 9                   This figure presents the Round Two

10    Interpretated Area of Disposal, and the areas within

11    the larger Area A, Area B/C, and Wood/Debris Disposal

12    Area, indicate those areas where there were higher

13    metallic anomalies detected by the geophysics.

14                   As a result, those locations were

15    specified for sampling; and in most cases, we got one

16    or more samples in each one of those locations that

17    gave us this particular type of anomaly.

18                      The  Round One  and Round Two data

19    were then compiled;  and as a result,  a Human Health

20    Risk Assessment was conducted.  And we conducted the

21    Human Health Risk Assessment considering the

22    contamination in the soil, the groundwater,  surface

23    water and sediment,  both current and future potential

24    exposure pathways and receptors were evaluated;  and

25    of course, carcinogenic and non-carcinogenic risks
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                                                  19
 1    were derived for carcinogenic and noncarcinogenic

 2    contaminants.

 3                      The current potential risk was

 4    evaluated by looking at a potential trespasser,

 5    somebody who could get through the fence from the

 6    park side and get onto the Site 12 study area on a

 7    very limited basis.   In general,  for this particular

 8    receptor, the carcinogenic risks  and the RCI values

 9    for potential derma contact,  and  accidental ingestion

10    of contaminants in soil,  fell within the-USEPA's

11    acceptable target risk range.

12                Noncarcinogenic risk values, His

13    were below one for Area B/C and the Wood/Debris

14    Disposal Area, as were the ICR's  within the

15    acceptable target risk range.  But noncarcinogenic

16    risk values, or hazardous debris,  were slightly  above

17    one im Area A, indicating that some type of

18    noncarcinogenic health response could occur

19    subseguent to thin type of exposure.

20                An evaluation of  risk  to future

21    potential receptors was also conducted.  The most

22    conservative future potential receptor is the future

23    potential resident;  someone who is going to build a

24    house on your site;  establish a well in the

25    groundwater below the site;  and someone who is going
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                                                           20
 1    to be exposed 365 days a year for a thirty-year

 2    lifetime; and we consider both children and adults in

 3    this assessment.

 4                      The carcinogenic risks obviously

 5    were not within the USEPA's target risk range,  and

 6    this was driven primarily by the presence of TCE and

 7    its degradation products in the Cornwallis Cave

 8    Aguifer.  And again, that's assuming that potable use

 9    of the Cornwallis Cave Aguifer is, in fact, going to

10    occur.

11                      We also had His in exceedences  of

12    1.0 in Area A,  which is not surprising because

13    certainly the less conservative current potential

14    exposure scenario for the trespasser also showed a

15    risk in the area.

16                   MR. THOMPSON:  Did the lab present

17    anything for hazards to children in Area A?

18                   MR. HOFF:  Yes,  we ran the IUBK

19    model for Area A, and it indicated,  with some

20    certainty, that this would,  in fact,  become a problem

21    for a child.  I'm not exactly sure what the

22    percentile value was that we derived,  but it was up

23    there.

24                    We also looked at the potential for

25    future construction workers to be exposed to
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 1    contaminants in soils,  and the carcinogenic risk for

 2    this particular future receptor was within USEPA

 3    target risk range,  10 -6 to 10 -4.

                    Again,  you had noncarcinogenic risk

 5    values,  or HI, that slightly exceeded 1.0,  and this

 6    was driven by the presence of antimony in subsurface

 7    soil.  Antimony is similar, in the  subsurface at Site

 8    12, to the station-wide background  values that we

 9    saw, so it is guite possible that the antimony that

10    we're seeing here is associated with natural

11    occurrences of that particular constituent, and not

12    an activity that has been conducted at Site 12.

13                    Again,  lead in Area A were above the

14    USEPA action limit of 400 milligram per kilogram,

15    which itself is derived from the IUBK; and if you

16    have several exceedences, if you have statistical

17    interpretation of data that produce mean values or

18    upper confidence level values in excess of 400,  it's

19    probably a pretty good bet that your IUBK model will

20    also indicate a risk.

21                   Weapon Station Yorktown being an

22    ecological activity presents us with some interesting

23    problems,  and these problems were brought to light an

24    part of the Round Two Ecological Risk Assessment.  It

25    was conducted for both aguatic and  terrestrial
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 1    receptors in the area of Site 12; and it considered

 2    all areas; Area A,  Area B/C,  the wood/Debris Disposal

 3    Area,  and the aquatic obviously considered Ballard

 4    Creek and its intermittent streams.

 5                   This particular overhead is trying

 6    to boil down and make some sense out of data we saw

 7    in the sediments.  When you evaluate the sediments, a

 8    first cut at the Ecological Risk.  Assessment is a

 9    comparison to screening criteria.  In this case

10    effect range low values and effect range median

11    values, and these are values that have been

12    established by toxicity studies, or through a

13    literature search for particular contaminants in

14    sediments that could cause some potential effect if

15    they are exceeded.

16                    We had a lot of exceedences of

17    ER-L's, and it was sort of difficult to make sense of

18    those exceeded,,  since they were both upstream and

19    downstream of our particular areas;  and ajain, we

20    don't have that fingerprint,  per se, that gives you

21    some statistical inference as to which of the areas

22    at Site 12 poses the greatest risk or presents the

23    biggest source of potential contamination to the

24    aguatic environment.

25                    What I did was, I broke the data
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 1    down even further in this particular overhead to

 2    evaluate where my potential risks were coming from,

 3    because we had sediment QI values that were

 4    relatively high,  I think in excess of 600 when we

 5    went to the ER-L, and in excess of 30 when we looked

 6    at ER-M's.

 7                   It's interesting to note here that

 8    the worst of the locations appear to be in the

 9    tributaries, particularly at 12SD12, which is

10    downstream from Area A; we have the presence of

11    PAH's,  not surprisingly, but we also detected some

12    PCB's in this particular location.

13                   We detected PCB, 1254, 1242 and 1248.

14    This particular figure has a typo on it.  The

15    concentrations should read PCB 1242, 530 micrograms

16    per kilogram, and that's J, 48, 340 micrograms per

17    kilogram, that's value J; and 54, 120 microgram per

18    kilogram, and that value should be J.

19                    In Ballard Creek Proper we have an

20    exceedence of ER-M at 12SW09.  This is somewhat

21    upgradient from Site 12, and it gives us an

22    indication that you can have PAH's occurring in the

23    sediments from other sources.  PAH's, like sediments,

24    present a very good sink for PAH's.  What we notice

25    is that a lot of the exceedences are by inorganics;
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 1    and those inorganics are manganese and zinc; and

 2    further down,  silver begins to pop up.  Also cadmium

 3    in a few locations.

 4                   And as you evaluate this overhead,

 5    what I'd like to do later on is I'll draw in some of

 6    the physical characteristics of the sediments that

 7    sort of play into the erosional nature of Ballard

 8    Creek,  and they give us some insight as to why these

 9    data might tell us what they do.

10                    But I think from an overall

11    perspective, when you break down the sediment QI

12    value,  constituents such as the PCB's, which are

13    likely site related, and I believe they're related to

14    Area A; but the pesticides, DDD, alpha-chlordane and

15    gamma-chlordane, these are big contributors.  And the

16    pesticides are likely due -- their occurrence is

17    likely due to past applications.  We don't see DDT.

18    It's interesting that we see DDD,  but we don't see

19    DDE or DDT.

20                    To recap some of the ecological

21    risks that we saw at the site, when we took a look at

22    the benthic data, the average Site 12 density of

23    benthics was several times higher than the average

24    background density.   One of the most important things

25    at Weapons Station is, when you take a sediment
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 1    sample and you take a benthic,  it's important to

 2    have,  obviously,  a reference station or sediment

 3    value that you can compare and make some sense of

 4    your data.

 5                   In this case, the density was

 6    higher,  and MBI's for Site 12 ranged from

 7    excellent -- this is upstream -- to 9.19,  which is a

 8    poor water quality indicator downstream of the areas.

 9                 Again, from a ccmparison standpoint,

10    MBI's, from a background standpoint, range from 4.3,

11    excellent; to about 7.6, indicating fair water

12    quality.   So we do have suggestion of some impact to

13    the benthics and to the sediments at Site 12.

14                      At  Site 12,  the diversity  of

15    benthics  was lower than the average diversity

16    calculated for background,  meaning that the numbers

17    of benthics macroinvertebrates that we saw, in terms

18    of the families,  were different from those we have

19    seen at background locations.

20                   In general,  other stressors could be

21    impacting these benthics.   And other stressors may be

22    erosion,  because of the nature of Site 12 and Ballard

23    Creek in particular.  You do have a lot of erosion

24    occurring, and we'll show you some data that may

25    support that.
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 1                   This overhead presents a breakdown

 2    of the MBI.   It's a density of the benthics and the

 3    number of TACSA that were identified per station.

 4    You can see we have our best water quality occurring

 5    at 12BM09, which is the furthest upstream location,

 6    but there's really no statistical degradation from

 7    that point on.  We have some 8's, some 7's at 12BM19;

 8    again, indicating poor water quality.

 9                   We also have the same situation

10    occurring in the intermittent streams downgradient of

11    Area A,  and on the back side of the Wood/Debris

12    Disposal Area.  But the interesting thing to note is

13    that the number of TACSA does go up as you move down

14    Ballard Creek; and this is really independent of the

15    Site 12 area proper.

16                   The other stressors that we were

17    speaking of, and the potential for erosion to affect

18    these results, can be evaluated on this particular

19    overhead.

20                    Benthics living in sediments are

21    very dependent upon their environment; and that

22    environment is usually evaluated by grain size

23    analysis, and it gives us an indication that when we

24    look at the benthic results, and we look at MBI's,

25    are we looking, at the same type of environment
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 1    physically; not just from a chemical standpoint,  but

 2    from a physical standpoint as we go up and down a

 3    particular stretch.

 4                  In this case, it appears that your

 5    greatest percentage of fine sands occur at 12SD09

 6    where we saw the best water guality.  And as you move

 7    down Ballard Creek,  you can see that your fine sands

 8    decrease somewhat,  and you have an increase in your

 9    medium sands,  and even your coarse sands,

10                   For instance,  at SD17,  we have fine

11    sand at only five percent, your medium sands are 25,

12    your coarse sands at 44; and also your percent silt

13    and clay picks up an well.  There's really no good

14    statistical way of evaluating this, because you're

15    not going to get a trend if you try to take a station

16    location and move downstream past the study area; but

17    what it tells me is that with all the erosion you

18    have in the intermittent ditch or intermittent

19    streams, and the other erosion in general to the

20    Ballard Creek water shed, you have the fine sand

21    winnowing out, and the erosion contributing more

22    medium and coarse sands to the creek proper.  And by

23    the time you get down to 12SD21, which is the

24    furthest downstream location, it almost represents an

25    area of well-mixed — or a well-mixed area, in that
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 1    you have about 20 percent fine sands; about 40

 2    percent medium sands,  25 percent coarse sands, and

 3    almost a representative fraction of silt and clay.

 4    So this could also have some effect on the benthic

 5    results, in addition to any type of chemical impact

 6    that we might see.

 7                   We're jumping around here a little

 8    bit, but going back to the Ecological Risk

 9    Assessment, the terrestrial component in particular,

10    we run terrestrial uptake models to determine what a

11    receptor might be exposed to through the course of

12    moving across the study area and their feeding and

13    living therein.  These uptake models consider the

14    uptakes associated with plants that may bioaccumulate

15    contaminants, incidental ingestion of dust while the

16    animal was eating; but there's also a water

17    components to this model.  And in this instance, we

18    used Ballard Creek as  the water source for the

19    terrestrial receptors  at each one of the locations:

20    Area A, Area B/C, and  the Wood/Debris Disposal Area.

21                   The terrestrial receptors that were

22    evaluated were taken from our habitat evaluation

23    studY; and we found evidence of Red Fox, Bobwhite

24    Quail, Eastern Cottontail, Raccoon, White-tail Deer,

25    or some similar  animal at Site 12.
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 1                    As with the sediments,  your first

 2   cut is always your comparison to screening values,

 3   and our first cut told us that Area A had exceedences

 4   of flora and fauna toxicity values for PAH's,  PCB's,

 5   limited nitramines or explosive compounds,  and

 6   inorganics at Area A.  We also had exceedences for

 7   PAH's and inorganics at Area B/C;  and in the

 8   Wood/Debris Disposal Area exceedences, for PAH's.

 9                    When we ran the uptake model, the

10   primary drivers or constituents that contributed to

11   the majority of the risk in-Area A were the inorganic

12   barium, cadmium,  iron,  and selenium and 1,3,5  TMB.

13   Now, 1,3,5 TMB was only located in a few locations,

14   or soil locations; but nonetheless, it has a fairly

15   low reference value, toxicity value.

16                    And that's typically what you do

17   with an uptake model:  You evaluate what's in the

18   soil, what can be uptaken by the plant,  and then what

19   the animal will collect an a body burden.  That body

20   burden can then be compared to some reference

21   toxicity data.

22                    This overhead breaks out soils and

23   the soil/water fractions of the model.  And the

24   reason we did this was to make the point that  Area A

25   is really the primary area of concern from an
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 1   ecological standpoint,  as well as human health,

 2   because when you look at the contribution to the

 3   model from a soil standpoint,  and from a soil/water

 4   standpoint,  you can see that most of our terrestrial

 5   receptors, the Raccoon, the White-tail deer, the

 6   Cottontail and the Shrew, has an elevated value, an

 7   elevated quotient index.

 8                    As you make the distinction in Area

 9   B/C and the Wood/Debris Disposal Area, you see that

10   only the Raccoon and the Short-Tail Shrew,  show

11   exceedences.  There's a reason for the Short-Tail

12   Shrew showing the exceedence,  and that has to do with

13   the how the Short-Tail  Shrew gets its sustenance.

14                    We assume that the Short-Tail Shrew

15   eats worms,  and there is really no good biological

16   concentration factor data out there to determine how

17   a worm uptakes contaminants from soil, so in essence

18   a worm to a Shrew, in these uptake models,  is a dirt

19   sausage; and as a result, the Short Tail Shrew pretty

20   much shown an elevated  QI everywhere, even for

21   background.

22                    The Raccoon shows a high quotient

23   index to the soil and water fraction, partly because

24   of the presence of cadmium in surface water; and we

25   do have a BCF value for cadmium in surface water.  As
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 1   we all know,  Raccoons eat fish.   If we assume that 60

 2   percent of the Raccoon diet is taken from fish taken

 3   from Ballard Creek.   Because of the presence of

 4   cadmium in Ballard Creek, and at a few locations,

 5   when you run the model to determine what the body

 6   burden of the fish would be that the Raccoon is going

 7   to eat, you get these high values.  And what we

 8   wanted to show here is that they're independent of

 9   the soil concentrations.

10                    So we believe that there's really no

11   significant ecological effect occurring in either

12   Area B/C or the Wood/Debris Disposal Area from the

13   soils therein; that when you got the elevated

14   guotient index, it's because of the water component

15   and not because of the soil.

16                    At this time I'm going to turn to

17   the floor over to Tamy Halapin,  and she's going to

18   run you through the FS and PRAP, and tell you what

19   our Proposed Remedial Action is for Site 12.

20                    MS. HALAPIN:  Hi.  Basically,  the FS

21   took all the information that the Round One and Round

22   Two RI compiled; a lot of information there, and it's

23   been a continual change in growth with the FS

24   Evaluation also.  The Feasibility Study is basically

25   based on the results of the human health and
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 1   ecological risk assessments.

 2                    The purpose of the FS was to

 3   identify potential remedial action alternatives for

 4   Site 12,  and basically the PRAP,  or the Proposed

 5   Remedial Action Plan, separated the media into two

 6   operable units at Site 12.   We wanted to focus on

 7   Area A soil; and we wanted to focus on everything

 8   else separately.

 9                    So Operable Unit III, as it's

10   distinguished in the PRAP right now, is the soil in

11   area A,  and Operable Unit IV is,  as it stands, soil

12   in Area B/C, the Wood/Debris Disposal Area, the

13   groundwater and surface water and sediment at Ballard

14   Creek.   The Remedial Action Objectives were developed

15   for Operable Unit III, and basically they were to

16   prevent erosion from Area A;  develop an alternative

17   that would meet that.  Prevent direct potential

18   contact with the lead contaminated soils, by either

19   human or/and ecological receptors; and to remediate

20   the soil to meet the remediation level of 400

21   micrograms per kilogram.  This is based on the EPA

22   action level.

23                   And also the Remedial Action

24   Objective for Operable Unit IV, the remaining media

25   at Site 12, was to insure that the guality of the

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 1   groundwatert both shallow and deep,  and that the

 2   surface water and sediment at Ballard Creek did not

 3   deteriorate over time.

 4                    So based on those Remedial Action

 5   Objectives, the FS determined and evaluated several

 6   different alternatives.   And for Operable Unit III in

 7   particular, there were  6 RAA's developed, and they

 8   range from the no action alternative, which is always

 9   used as a baseline for  comparison.

10                    The next alternativet RAA 2,

11   included institutional  control; such as,  land

12   restrictions, deed restrictions, monitoring,

13   involving surface water monitoring at Area A,  and

14   erosion control measures to try to prevent the

15   further erosion at Area A.

16                    Remedial Alternative 3 was a soil

17   and clay cover to be placed on the lead contaminated

18   soils at Area A.

19                    Remedial Action Alternative 4 was to

20   excavate the lead contaminated soil and landfill it

21   off site.

22                    Number 5 was an innovative idea to

23   in-place solidify the lead contaminated soil by

24   adding a cement-type mixture forming a solid mass and

25   then capping over that  with soil and clay cover.
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 1                    And Alternative 6 was a treatment

 2   alternative of excavating the ash in the soil and

 3   soil washing and leaching it on site and replacing

 4   the treated soil.

 5                    Basically we will go over some of

 6   the main components of each of these alternatives.

 7   As I said,  the no action would be nothing would be

 8   done at the site, it would remain as-is.  This is

 9   just a baseline alternative that's included in every

10   FS just to use for comparative purposes.

11                    The net present value:   The FS

12   calculates a net present value for every alternative

13   it evaluates,  and the no action obviously is zero.

14                    Remedial Action 2 was the

15   institutional controls with the soil, surface water

16   monitoring, and erosion control.  That has a Net

17   Present Value estimated at $670,000.  It would be,

18   like I said, deed restrictions and land restrictions,

19   and putting rip rap along the stream channel leading

20   from Area A down Ballard Creek.

21                    Number three is a soil and clay

22   cover, which would be placed over a foot of clay and

23   the topsoil placed -- I think that's what we wrote in

24   the FS, but placed over the lead contaminated area,

25   any place exceeding 400 micrograms per kilogram, and
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 1   would also include a lot of erosional control

 2   measures in the remaining areas that weren't above

 3   that level, just to prevent the erosion so it meets

 4   the one objective.  It would also include the same

 5   long-term monitoring program as Remedial Action 2,

 6   the surface water monitoring,  the same institutional

 7   controls.  The Net Present Value for this one was

 8   estimated at one million dollars.

 9                    For Number 4,  the Offsite Landfill

10   Disposal, basically to excavate the soil that

11   exceeded the action level, had the same monitoring

12   program, institutional controls and also the erosion

13   control measures, it was estimated at 4.8 million

14   dollars.

15                    Number 5, the In Situ Soil

16   Stabilization/Solidification Alternative would be to

17   in-place mix the soil with the cement.  It would have

18   a soil clay cover on-top of the treated mass, and

19   again, it would have the same monitoring program and

20   institutional controls and erosion.  It was estimated

21   at 1.4 million dollars.

22                    And finally Alternative 6 would be

23   to excavate the soil that exceeded the level, run it

24   through on-site treatment system consisting of soil

25   washing and soil leaching, and again apply the same
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 1   other monitoring and erosion controls.   It was

 2   estimated at 2.9 million dollars.

 3                    So the purpose of the  FS was to go

 4   through and evaluate -- develop these alternatives

 5   and evaluate them.   At that step,  the Navy prepared a

 6   Proposed Remedial Action Plan of what they want their

 7   remedy to be for  the site, and that's  basically the

 8   purpose of tonight's meeting.

 9                    The Navy has preferred the

10   Alternative Number 3, the soil cap and clay cover for

11   Operable Unit III;  and for Operable Unit IV,  it is as

12   it's presented in the PRAP, for long-term monitoring

13   of the soil, of the surface water, sediment,  and

14   groundwater.  And the details of this monitoring will

15   be determined and developed and agreed to by all the

16   parties in a separate document that will be part of

17   the Long-term Monitoring Work Plan.

18                    MR. THOMPSON:  Rich, at this point I

19   have a guestion.

20                    MR. HOFF:  Sure.

21                    MR. THOMPSON:  I  notice a lot of the

22   alternatives that are being evaluated are based on

23   the lead 400 level.  There were some other metals

24   that were indicated an being risk drivers.  Is there

25   any other evaluation done for those other metals?
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 1                    MR.  HOFF:   We didn't do an

 2   evaluation of clean-up levels for other metals, but

 3   we did get that comment from the EPA, and the basis

 4   of the comment was that when we proposed an area that

 5   was to fall under the cover, they wanted that area

 6   extended to also include two or three locations where

 7   I think we had risks; and these were risks, I think,

 8   primarily to the  terrestrial receptor to cadmium and

 9   some of the other inorganics.  And what we did was,

10   rather-than screen values for the ecological, we

11   simply extended the cap to include those areas as

12   well.

13                    MR.  THOMPSON:  So there will be some

14   sort of criteria for extending that cap?  In other

15   words, sample soil, and if you get cadmium at a

16   certain level, the cap will extend?

17                    MR.  HOFF:   Yes, we'll make that

18   determination in  the Final Record of Decision.

19                    MR.  THOMPSON:  In that going to

20   cause the cost to increase significantly?

21                    MR.  HOFF:   Not substantially.  I

22   think that when you do the cost, and Tammi would

23   probably agree with me, for FS purposes, by the time

24   this goes to the  RAB contractor, those numbers are

25   pretty much cartoons to begin with.  But the areas
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 1   that it extends to are relatively close in boundaries

 2   as,  we've described earlier in the FS,  and then later

 3   in the PRAP,  so I wouldn't expect that it would

 4   substantially increase the cost.

 5                    MR.  THOMPSON:  It will help in the

 6   Final ROD to close that loop.  In other words,

 7   present the risks up front.  Here's the organic,

 8   here's the risks.  Present the risks.  You don't

 9   really discuss that in the selection of the

10   alternative.

11                    MR.  HOFF:  Yeah, There's a number of

12   things we need to do in the final ROD,  and what we're

13   going to try to do is issue an Interim Final to all

14   parties so we can get the blessing,,  not only from the

15   State, but also from RAB, and most importantly, you

16   legal folks.

17                    And as Tammi goes through here,  her

18   next overhead in going to present the proposed action

19   and the operable units that have broken out based on

20   a lot of the comments and back and forth between the

21   Navy and the agencies.

22                    MS.  HALAPIN:  Basically, just to

23   show a display of the proposed alternatives, it's

24   this portion here, that's the hatch area, would be

25   the soil/clay cover for the approximate boundaries.
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 1   As Rich did say,  this area right in here was extended

 2   to meet one of the comments.

 3                    MR.  HOFF:  Yeah,  I think we brought

 4   it out in --

 5                    MS.  HALAPIN:   That is extended

 6   already.

 7                    MR.  HOFF:  Yeah,  it extends

 8   towards -- along these lines  where we just moved the

 9   boundary out to include those locations, but we'll

10   make sure that's presented in the final.

11                    MS.  HALAPIN:   Then the other area,

12   the shaded area,  is where, in general, the erosion

13   controls measures would be installed and in place,

14   basically behind the incinerator and along the stream

15   channel.   That's a real conceptual model of what the

16   actual alternative would consist of.

17                    The rational for the remedy that's

18   been selected for OU III is that basically it

19   provides the most appropriate and cost effective

20   level of protection that the  Navy considers that

21   should be appropriate for the nature of the

22   contamination that's there.  Also the cap, you

23   definitely want,  as long an it's maintained

24   adeguately, will provide a physical barrier to lead

25   contaminated soil.  That's our main concern, the
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 1   dermal contact and trespassers having access and

 2   contact with it.   And the cover will effectively

 3   isolate the soil   if it is adequately maintained.

 4                    The rationale for selection of the

 5   remedy for OU IV is that basically the groundwater

 6   will not be remediated under this.  The TCE levels

 7   detected in the groundwater did not exceed the

 8   remediation levels that were determined in the

 9   Feasibility Study.  In addition to that,  the geology,

10   the hydra-geology of Site 12 is very complicated.

11   There are solution channels that are very common in

12   shallow aguifers,  and erosion, and it's something

13   that would make it technically very difficult to

14   install and implement a typical pump-and-treat-type

15   of groundwater treatment system, or something similar

16   to that, so there's also other types of limitations

17   that would come into play with the groundwater.

18                    With respect to the sediments,

19   again, they're not going to be remediated under this

20   alternative.  Basically the treatment of the

21   sediments require the dredging of Ballard Creek

22   and/or the tributaries, and sometimes, most of the

23   times, it has more of a significant impact to the

24   ecological environment than by leaving things as they

25   are.  And in addition to that, there are no
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 1   enforceable remediation levels at this time for

 2   sediments to be considered protective of the

 3   environment.

 4                    For the PRAP itself, the public is

 5   encouraged to participate in the decision-making

 6   process.   The PRAP is the Navy's selected remedy

 7   right now,  but the actual remedy can change, and

 8   what's presented in the ROD is based on input from

 9   agencies  and the public.

10                    Any written comments can be

11   forwarded to Mr. Tom Black, who is here, and at the

12   address that's on the slide.  And comments will be

13   accepted  until the end of the public comment period,

14   which is  August 14th, 1996.

15                    Since the submission of the Final

16   PRAP in June, there's been a lot of discussion

17   between the Navy and the agencies and the receipt of

18   different comments,  and there have been -- the Navy

19   has considered some modifications already that will

20   result in the Record of Decision, and these

21   modifications are not final yet.  Again, they will be

22   determined once all the comments are received and the

23   public comment period is over.

24                    But just to give you a brief of idea

25   of what some of them are, right now we're determining

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 1   that the ROD now will be separated into these

 2   Operable Units.   Operable Unit III will stay the

 3   same,  the soil in Area A.  Operable Unit IV, will

 4   only include the soil in Area B/C and the Wood/Debris

 5   Disposal Area; and Operable Unit V will include the

 6   groundwater, surface, sediment in Ballard Creek.

 7                    And then to go along with that, the

 8   remedy that will be presented will be the same thing

 9   for Operable Unit III, RAA-3, the soil and clay

10   cover,  and it will include long-term monitoring as

11   per the NCP, meaning that every five years the

12   surface water will be monitored.  Every five years a

13   review of that data will be evaluated, and that will

14   be long-term, indefinitely.

15                    OU IV will be -- and that is for the

16   soil in Areas B/C, and the Wood/Debris Disposal Area,

17   that will be no action with institutional controls,

18   basically land restrictions, deed restrictions.

19                    OU V, which in the groundwater,

20   surface water sediment, will have no action with

21   long-term monitoring, as per the NCP, and

22   institutional controls, and sediment monitoring as

23   agreed to by the parties, which means it won't be

24   locked into the every five years review, but just

25   evaluate if the sediment guality is being still
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 1   affected.   We'll definitely have something we can

 2   Agree to what type of monitoring schedule.

 3                    That's basically to-date what's been

 4   developed for Site 12,  and what the Navy -- where the

 5   Navy is heading with it.  But again,  there's still

 6   plenty of time yet for additional comments, and we'll

 7   see from that.  Thanks.

 8                    And I guess guestions and answers

 9   will be next.

10                    MR. DEWING:  Has there been any

11   input from the National Park Service on any of this?

12                    MR. BLACK:  Yes, we have received

13   comments from the National Park Service on the PRAP

14   with the two Operable Units, and the Park Service has

15   reiterated it's desire to see additional data

16   collected for Ballard Creek, the surface and

17   sediments therein, but they did not seem to be in

18   disagreement with the selection, the remedy, or the

19   break down of the Operable Units.

20                    The reason for the changes to the

21   Operable Units are -- there are several.  One is you

22   have potential for adverse ecological effects

23   occurring in sediments; is that from groundwater

24   infiltration of Ballard Creek?  Is that from erosion?

25   Is that from physical stressors that may be present
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 1   that we talked about in the sediments?

 2                    What we hope to do through this

 3   particular break-out is consider the Department of

 4   the Interior,  the Parks, and their desire to see

 5   additional data collected for the ecological,

 6   particularly Ballard Creek; but also make sure that

 7   ROD's legal folks are happy with the way that we are

 8   specifying the long-term monitoring, because it's

 9   very difficult, I think, under -- in fact,  I think as

10   we get into this  more and more, the only way I see we

11   can agree to long-term monitoring under the NCP, is

12   if we leave a waste in place.  And I guess by saying

13   "a waste in place", that would be anything that would

14   be residual before, during, or after some treatment,

15   or under a no action scenario.

16                    MR. THOMPSON:  It's when you leave a

17   waste in place, such that the land use or the use of

18   that area is restricted to some degree,  so that every

19   five years you review data and determine whether or

20   not that restriction still needs to be in place.

21                    MR. HOFF:  Before we didn't really

22   make the distinguishment about how we were going to

23   monitor.  There was some verbiage in the PRAP that

24   described that we would, among the parties, decide

25   upon a long-term monitoring plan, that would be a
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 1   primary document under the FA.   That doesn't really

 2   give the legal folks,  ROD's legal folks,  the closure

 3   that they need to say, We will  sign on this Record of

 4   Decision; but by doing this,  we hope to establish the

 5   fact that the data is  eguivocal in indicating Area A

 6   is probably the biggest culprit of human health and

 7   ecological risk perspective at  Site 12.  But we also

 8   acknowledge the fact we are leaving TCE in

 9   groundwater above MCL, but below clean-up goals that

10   were developed for beneficial use.

11                    The reason we  did that is we believe

12   the groundwater in that area will not be used for

13   public purposes.  It's not currently, and we don't

14   believe it could be in the future.  But we are lucky

15   in that we do have the Yorktown Confining Unit that

16   has kept this TCE from migrating to the Yorktown

17   Aguifer, which itself  In not used for public purposes

18   in the vicinity of the station, but it's certainly --

19                    MR. DEWING:  What did you say was

20   not used?

21                    MR. HOFF:  The upper Yorktown.

22                    MR. DEWING:  The Yorktown Eastover

23   Aguifer?

24                    MR. HOFF:  There are some

25   distinguishments about the Yorktown Eastover.  It's a
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 1   fairly large aquifer.

 2                    MR.  DEWING:   Yes,  I know.

 3                    MR.  HOFF:   What we're saying is,  the

 4   Upper Yorktown Eastover,  in the vicinity of Site 12

 5   is not used as potable.

 6                    MR.  DEWING:   Okay.   Because my well

 7   goes into the Yorktown Eastover.

 8                    MR.  HOFF:   Right.   I think we talked

 9   about that here before.

10                    MR.  DEWING:   Yes.

11                    MR.  HOFF:   I know Allen Brockman has

12   a lot of good data.

13                    MR.  DEWING:   I've seen it.

14                    MR.  HOFF:   And it's interesting,

15   Allen has really provided us with a lot of good

16   insight on the groundwater in the region of Weapons

17   Station Yorktown.  And when Allen first got involved,

18   the question was, would these sediments qualify, and

19   I think at first my reaction was, being a consultant

20   to -- an environmental consultant,  if it's wet, we

21   have to evaluate it as an aquifer.   He's come up with

22   some very interesting data that suggests that in

23   certain portions of these aquifers,  even though

24   you're seeing what we may not consider to be a

25   confining unit -- when we say a confining unit, we're
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 1   talking about a nice,  thick,  dry clay that shows

 2   distinguishment between aguifers.   He is indicating

 3   that there are formations that can grade out to the

 4   extent where you just do not have any water movement.

 5   They might be wet,  but they are,  in essence, acting

 6   as a barrier.  It's sort of a good news, bad news,

 7   good news; or it's  a bad news, good news,  bad news

 8   situation; however  you want to look at goundwater at

 9   Site 12.

10                    I  think the data indicates that the

11   former source was the industrial area and the UST's.

12   we have a good handle on both of the plumes and the

13   direction they're headed.

14                    The bad news is that they discharge

15   to Ballard Creek, and we're seeing that at relatively

16   low levels; not above any State criteria and

17   certainly not above any of the Federal criteria.  The

18   good news is that they're not making it, at least in

19   this area of Yorktown.

20                    MR. MARTIN:   I guess the note I

21   wanted to make was, Rich Strycker,  who was going to

22   do the guestion and answers,  he called me this

23   morning and he's got a second child apparently on the

24   way, so he had to go to the hospital with his wife.

25   That's why he's not here tonight,  and I guess with
                             FOX REPORTING
         21 Michael's Woods Drive,  Hampton,  Virginia 23666
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 1   that,  you can close or I can close it.

 2                    We appreciate everybody coming and

 3   we'll see you at the next public meeting.  Thank you.

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                             FOX REPORTING
         21 Michael's Woods Drive, Hampton,  Virginia 23666
                              (804)  827-7843

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