Superfund Record of Decision Naval Surface Warfare-Dahlgren Site 2 Dahlgren VA


                                   EPA/ROD/R03-97/179
                                   1997
EPA Superfund
     Record of Decision:
     NAVAL SURFACE WARFARE CENTER - DAHLGREN
     EPA ID: VA7170024684
     OU02
     DAHLGREN, VA
     09/29/1997

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                                                   TABLE OF CONTENTS

       SECTION                                                                                    PAGE

       1. 0    THE DECLARATION 	1-1
              1.1    SITE NAME AND LOCATION 	1-1
              1. 2     STATEMENT OF BASIS AND  PURPOSE  	1-1
              1. 3     DESCRIPTION OF  THE SELECTED REMEDY 	1-1
              1. 4     STATUTORY DETERMINATIONS  	1-3

       2 . 0    SUMMARY 	2-1
              2.1     SITE NAME,  LOCATION,  AND  DESCRIPTION 	2-1
              2 . 2     SITE HISTORY AND  ENFORCEMENT ACTIVITIES  	2-1
              2.2.1   History of Site Activities  	2-1
              2.2.2   Previous Investigations 	2-5
              2.2.3  Enforcement Actions  	2-5
              2.2.4   Highlights of Community Participation 	2-5
              2 .3     SCOPE AND ROLE  OF RESPONSE  ACTION AT SITE  2  	2-6
              2 . 4     SUMMARY OF SITE CHARACTERISTICS  	2-6
              2.4.1   Sources of Contamination  	2-6
             2.4.2    Description of  Contamination 	2-8
              2.4.3   Contaminant Migration 	2-11
              2 . 5     SUMMARY OF SITE RISKS 	2-12
              2.5.1   Human Health Risks  	2-12
              2.5.2   Environmental Evaluation  	2-15
              2.5.3   Development of  Preliminary  Remediation Goals  (PRGs)  	2-15
              2.5.4   Assessment of Site 2  Risk 	2-19
              2 . 6     DESCRIPTION OF  ALTERNATIVES 	2-19
              2 . 7     SUMMARY OF THE  COMPARATIVE  ANALYSIS  OF ALTERNATIVES  	2-22
              2.7.1   Threshold Criteria  	2-22
              2.7.2   Primary Balancing Criteria  	2-23
              2.7.3   Modifying Criteria  	2-25
              2 . 8     THE SELECTED REMEDY  	2-25
              2.8.1   Performance Standards 	2-27
              2.9     STATUTORY DETERMINATIONS  	2-28
              2.9.1   Protection of Human Health  and  the Environment  	2-28
              2.9.2   Compliance with ARARs 	2-29
              2.9.3   Cost-Effectiveness  	2-29
              2.9.4  Utilization of Permanent Solutions and Alternative Treatment Technologies
                     or Resourse Recovery  Technologies to  the  Maximum Extent
                      Practicable 	2-29
              2.9.5  Preference for Treatment as  a Principal Element  	2-29

       3.0    RESPONSIVENESS  SUMMARY  	3-1
              3.1     BACKGROUND ON COMMUNITY INVOLVEMENT  	3-1

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APPENDICES
Appendix A
Appendix B
Appendix C
       Commonwealth of Virginia Concurrence with the Selected Remedy
       Responsiveness Summary
       Applicable or Relevant and Appropriate Requirements
NUMBER

2-1
2-2
2-3
2-4
NUMBER

2-1

2-2
2-3
2-4
2-5
                                  LIST OF FIGURES
NSWCDL Location Map 	2-2
IR Site Locations 	2-3
Site Map, Site 2- Fenced Ordnance Burial Area 	2-4
Estimated Area of Soil Contamination Above PRGs 	2-7

                           LIST OF TABLES

                                                         PAGE

Comparison of Groundwater Data 	2-9

Ecological Risk Management 	2-16
Summary of Surface Soil PRGs 	2-17
Summary of Subsurface Soil PRGs 	2-18
Summary of Groundwater PRGs 	2-18
                                                                             PAGE

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1.0 THE DECLARATION

1.1 SITE NAME AND LOCATION

Site 2 Fenced Ordnance Burial Area
Naval Surface Warfare Center
Dahlgren Virginia

1.2 STATEMENT OF BASIS AND PURPOSE

This decision document presents the selected remedial action for Site 2 Fenced Ordnance
Burial Area the Naval Surface Warfare Center, Dahlgren Site (NSWCDL) Dahlgren, Virginia.
This document focuses on remedial decisions for Site 2 at NSWCDL and the term "site" in this
document refers to Site 2. This determination has been made in accordance with the
Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA),
as amended by Superfund Amendments and Reauthorization Act of 1986 (SARA), and to the
extent practicable, the National Oil and Hazardous Substances Pollution Contingency Plan
(NCP). This decision is based on the administrative record for this site.

The Commonwealth of Virginia concurs with the selected remedy (see Appendix A).

ASSESSMENT OF THE SITE

Actual or threatened releases of hazardous substances from this site, if not addressed by
implementing the response action selected in this Record of Decision (ROD), may present an
imminent and substantial endangerment to public health, welfare, or the environment.

1.3 PESCRIPTION OF THE SELECTED REMEDY

The Navy will manage the remediation of the landfill in two phases. The remedial action
selected in this Record of Decision (ROD) addresses contamination associated with Site 2
landfill contents, surface and subsurface soils and groundwater. Possible contaminated surface
water and sediments in Gambo Creek near Site 2 will undergo further remedial evaluation as
part of the Gambo Creek Ecological Assessment and a separate ROD will be issued for Gambo
Creek, as appropriate.

The selected-remedy for Site 2 is Alternative 4 which involves the removal of soils exceeding
remediation goals; removal of the western and southern trenches and debris piles; backfilling
with clean fill; consolidating all removed wastes onsite, recycling recyclable materials from debris
piles offsite; capping the fenced area and consolidated-waste and soils; and providing
institutional controls to limit the site to future industrial use and to exclude shallow groundwater
use. Surface water and groundwater shall continue to be monitored.

The major components of the selected remedy are:

The Navy shall remove soils which are above the Remedial Action Objectives (RAOs) in
selected areas on the site. These soils shall be consolidated underneath the fenced area landfill cap.

The Navy shall remove the southern and western debris piles. The Navy shall recycle the
recyclable material in the debris piles and consolidate the remaining wastes underneath the
fenced area landfill cap.

The Navy shall excavate the wastes from the southern and western trenches and backfill with
clean fill. The Navy shall consolidate the excavated wastes underneath the fenced area landfill cap.

The Navy shall construct a multi-layer cap over the fenced area and the area over the excavated
trenches. The cap shall be consistent with RCRA Subtitle C reguirements and shall consist of a
minimum of 24 inches of topsoil and vegetative cover underlain by a filter layer and 12 inches of
drainage (minimum 10 -2 cm/sec), a minimum 20 mil geomembrane, and 24 inches of compacted
soil or clay, or eguivalent design achieving a maximum hydraulic conductivity of 10 -7 cm/sec.
The cap shall include a passive gas collection system and a perimeter drainage system.

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The Navy shall develop and implement an operating and maintenance plan for the landfill.  The
Navy shall also implement all post-closure requirements for the landfill, including the certification
of closure to the Regional Administrator within 60 days of completion of the cap.

The Navy shall institute the following institutional controls within 60 days of completion of the
cap:  a real property description notation, Base Master Plan notations, and limited site access.
Fencing shall be erected around the landfill area and signs shall be posted which state that
hazardous wastes are present.  The Base Master Plan shall note the area as one in which
construction changes can not occur, residential development can not occur, shallow groundwater
can not be used, and site access shall be limited.  A notation shall be filed in the real property
file maintained at Engineering Field Activity, Chesapeake  (EFA Ches) (US Navy) for this site
indicating the extent of the area and the fact that hazardous wastes are present.  Institutional
controls shall also include the following:  Within 60 days of closure  (capping),  the Navy shall
produce a survey plat indicating the location and dimensions of landfill cells or other hazardous
waste disposal units with respect to permanently surveyed benchmarks.  This plat shall be
prepared and certified by a professional land surveyor.  The plat shall contain a note,
prominently displayed, which states the owners obligation to restrict disturbance of the
hazardous waste disposal unit; post-closure use shall prohibit residential use,  shall prohibit
access or use of groundwater underlying the property for any purpose except monitoring, and
shall never be allowed to disturb the integrity of the final cover, liners, or any other components
of the containment system, or the function of the facility's monitoring systems.   No later than 60
days after closure, the Navy shall submit to the county board of supervisors a record of the type,
location, and quantity of hazardous wastes disposed of within each cell or other disposal unit of
the facility.  As soon as practicable, the owner shall record, in accordance with state and local
law, a notation on the deed to the property - or on some other instrument which is normally
examined during title search - that will in perpetuity notify any potential purchaser of the property
that the land has been used to manage hazardous wastes, that its use is restricted as described
above, and that a survey plat and a record of the type, location, and quantity of hazardous
wastes disposed of have been filed with the local government.  If and when the property is
transferred out of the federal government, the deed shall contain the survey plat, the notation
that the property was previously used to manage hazardous wastes and that its future use is
restricted, and other deed restrictions as appropriate.

The Navy shall institute groundwater monitoring at the perimeter of the landfill cap and shall
continue monitoring for 30 years, the post-closure time period as required by the Resource
Conservation and Recovery Act (RCRA).

The Navy shall monitor the drainage system, surrounding the cap, surface waters,  and
sediments in Gambo Creek adjacent to Site 2.  The frequency of analysis and the length of time
for monitoring shall be developed in the Operation and Management Plan.

Implementation of the selected remedy will address the principal threats at the site by reducing
the potential risk to human health and the environment associated with the surface soils and
landfill contents.  Additionally, this action should reduce the risk associated with potential
leaching of landfill contents to the groundwater beneath the site.  The selected remedy will meet
the substantive requirements for the proper closure of a RCRA subtitle C landfill.

1.4    STATUTORY DETERMINATIONS

The selected remedy for Site 2 is protective of human health and the environment, complies with
Federal and State requirements that are legally applicable or relevant and appropriate to this
action, and is cost-effective.

The selected remedy for Site 2 addresses the containment of surface soils and landfill wastes at
Site 2.  The selected remedy will provide for the long-term reduction of leachate generation and
possible contamination of the groundwater beneath the landfill.

This remedy fulfills the RCRA Subtitle C regulations for closure by using a design for the cap
which follows EPA guidance and VDEQ requirements.  The installation of a RCRA Subtitle C
cap will eliminate direct contact, ingestion, and inhalation threats from contaminated soils and
will reduce the leaching of contaminants to groundwater by controlling precipitation entering the
landfill and minimizing eachate generation.  Also, the permanent RCRA Subtitle C cap will
stabilize existing conditions at the landfill.

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The selected remedy for Site 2 will be constructed to meet all applicable or relevant and
appropriate requirements (ARARs) whether chemical-, action-, or location-specific. No waivers
of any ARARs are requested. Cappinq is a permanent solution and is a common remedy for
land-filled wastes. Containment in the form of cappinq is applicable and appropriate for a site
with buried ordnance.

This remedy utilizes permanent solutions and alternative treatment (or resource recovery)
technoloqies to the maximum extent practicable. However, because treatment of the principal
threats was not found to be practicable, this remedy does not satisfy the statutory preference for
treatment as a principal element.

Because this remedy will result in hazardous substances remaininq on-site above health based
levels, a review will be conducted within five years after commencement of the remedial action
to ensure that the remedy continues to provide adequate protection of human health and the environment.

2.0 DECISION SUMMARY

2.1 SITE NAME, LOCATION, AND DESCRIPTION

This Record of Decision (ROD) is issued to describe the Department of the Navy's (Navy)
selected remedial actions for Site 2, Fenced Ordnance Burial Area, at the Naval Surface
Warfare Center, Dahlqren Site (NSWCDL), Dahlqren, Virqinia (Fiqure 2-1). The Fenced
Ordnance Burial Area is one of several Installation Restoration (IR) sites (Fiqure 2-2) located at
the NSWCDL facility. Site 2 is situated on the "Mainside" of the base and is bounded on its
western side by Gambo Creek (Fiqure 2-3).

Site 2, formerly used for disposal of various metal ordnance items, is located close to the eastern
shore of Gambo Creek and southeast of Site 12, the Chemical Burn Area (Fiqure 2-2). Site 2
consists of a small fenced area, five trenches south and west of the fenced area, and two surface
debris piles. Access to Site 2 is from Baqby Road which, in conjunction with Stump Dump Road,
forms the northern edqe of the site. Gambo Creek and associated marsh areas form the western
and southern site boundaries. The eastern border of Site 2 is defined by the limits of the
qeophysical survey conducted durinq the Remedial Investiqation (RI) (Fiqure 2-3). The
qeophysical survey did not, however, investiqate the fenced area of the site due to the potential
danqers associated with ordnance.

Adjacent land has been used for open burninq of explosive waste, as an aerial bombinq ranqe,
and as a natural habitat for native plant and animal species. Laboratory and office spaces are
located within 1500 feet to the northeast of Site 2, and within 1000 feet to the southwest of the Site.

The site is located on a relatively flat parcel of land, with elevations ranqinq between 15 and 20
feet above mean sea level (msl). Waste materials were disposed in trenches in areas within and
outside of the fenced area. There is no surface expression of trenchinq, with the possible
exception of piles of excess soil remaininq from the excavation and filling operations. The
northeastern portion of the site is sparsely vegetated; the remainder of the site is wooded with
mature deciduous trees or small pine trees indicatinq qrowth after landfill operations ended.

Groundwater production wells, which are located over 4,000 feet south of Site 2 supply potable
water to NSWCDL.

The closest residences, on-base Navy housinq consistinq of over 150 homes, are within 6,000
feet southwest of Site 2.

Two drainaqe swales located alonq the western portion of the site direct surface flow toward
Gambo Creek and the surroundinq marsh west of the site. Gambo Creek flows south from the
site, joininq a tributary east of the site further downstream. Based on the topoqraphic features at
this location, site drainaqe is principally to the south-southwest, toward a marshy area adjacent to
Gambo Creek. There is also a drainaqe component to the eastern tributary of Gambo Creek.

2.2 SITE HISTORY AND ENFORCEMENT ACTIVITIES

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2.2.1 History of Site Activities

Evidence based on a study of aerial photography by the USEPA in 1992 shows that activity at
Site 2 began around 1943, as observed by a small cleared area on photos appearing
approximately 100 feet south of Bagby Road. In a 1952 photo, a large cleared, sguare, fenced
area south of Bagby Road was apparent. A pile of dark-colored dirt was present in the northwest
corner of the site.

In the early 1970s a fenced landfill area was excavated in the northeast corner of the site and
was reportedly used for the disposal of metal ordnance materials that may have contained
explosive residue. The fenced area is approximately 150 feet by 150 feet, and is surrounded by
an 8-foot-high chain link fence. In addition, asbestos pipe wrappings, rinsed pesticide
containers, ordnance hardware, and machine parts were buried in this area. Additional wastes
that may have been buried at Site 2 within the current fenced area include an unknown guantity
of "cut up gun barrels," residue from small arms ammunition and potentially explosive ordnance.
"Misch" metal, which may be composed of radioactive thorium and rare earth metals alloyed with
magnesium or nickel, may have been buried at Site 2, although ultimate disposal details were
not recorded (Fred C. Hart Associates, Inc., 1983). According to facility personnel, drums were
filled with "Misch" metal immersed in waste oil prior to placement in the trenches. Records of
disposal activities at Site 2 have revealed that some of the buried materials were wastes
recovered from burning activities at nearby Site 12. Records do not mention the burial of drums
or waste oils, but do report the burial of a large guantity of ordnance materials, scrap metal and
machinery parts primarily on the southern portion of the fenced area.

Two additional trenches within the current fenced area appeared on aerial photographs in the
early to mid- 1980s. In the early 1980s, areas of the site to the east and west side of the fence
were cleared of vegetation.

Trenching operations outside the current fenced area occurred between 1976 and 1988. Four
trenches outside and immediately south of the current fenced area reportedly received aircraft
scrap, sonar buoys, nicad sonar batteries and non-explosive missile materials. These trenches
were each approximately 100 feet long by 20 feet wide. An additional trench west of the fenced
area (and approximately the same dimensions) reportedly received seawater batteries and nicad
batteries, but during test pit operations conducted as part of the RI, only seawater batteries and
magnesium wet cell batteries were found. This information has been updated based on the field
investigation of the site, and is discussed in more detail in the Remedial Investigation (RI) report.

A surface debris pile approximately 100 feet by 50 feet containing wood, scrap metal, and rubber
is located in the west side of the site. A second, smaller, debris pile containing partially melted
aircraft rocket launchers is present in the southern portion of the site. (Figure 2-3).

2.2.2 Previous Investigations

Prior to the Remedial Investigation (RI), no environmental sampling and analysis was conducted
at Site 2. An Initial Assessment Study (IAS) for NSWCDL, conducted in 1981, concluded that a
Confirmation Study consisting of radiological monitoring should be completed to determine the
presence of thorium-contaminated wastes and to determine whether a threat to human health
existed at Site 2. However, Site 2 was not investigated as part of the Confirmation Study, due to
the potential presence of low-level radioactive waste. Other studies that were completed at
NSWCOL of relevance to Site 2 included the completion of aerial photography, a hydrogeologic
survey, and ecological surveys completed in 1991-1992.

2.2.3 Enforcement Actions

There have been no enforcement actions taken at Site 2. The Navy has owned this property
since the early 1900's and is identified as the responsible party.

2.2.4 Highlights of Community Participation

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In accordance with Section 113 and 117 of CERCLA, the Navy held a public comment period
from July 30, 1997 through August 29, 1997 for the proposed remedial action described in the
Feasibility Study for Site 2 and in the Proposed Plan.

These documents, as well as the RI reports, were available to the public in the Administrative
Record and information repositories maintained at the Smoot Memorial Library, King George,
Virginia; the Dahlgren Laboratory General Library, Dahlgren, Virginia; and the Dahlgren
Laboratory Public Record Room, Dahlgren, Virginia. Public notice of document availability and
of the public meeting was provided in The Freelance Star newspaper on July 29, 1997 and a
Public Meeting was held in the King George Administration Building on August 6, 1997. No
written comments were received during the comment period and the copy of the certified
transcript of the Public Meeting is presented in Appendix B.

2.3 SCOPE AND ROLE OF RESPONSE ACTION AT SITE 2

Past disposal operations at Site 2 have contaminated surface and subsurface soils. The NCP
(40 CFR 300.430(a)(1)(ii)(A)) states "Sites should generally be remediated in operable units
when early actions are necessary or appropriate to achieve significant risk reduction guickly,
when phased analysis and response is necessary or appropriate given the size or complexity of
total site cleanup."

The selected remedy identified in this ROD addresses contamination associated with Site 2 as
identified in the RI Report, the Addendum RI Report, and the Feasibility Study (FS) Report for
Site 2. The recommended response actions (or preferred alternatives) for these media are
identified and the rationale for their selection is described in Section 2.7.

The selected remedy will reduce the potential risk to human health and the environment
associated with the surface and subsurface soils. The remedy consists of the removal of wastes
located in trenches and debris piles outside of the fenced area, and consolidating these materials
into a single on-site disposal area. Soil containing elevated levels of contaminants from other
areas of the site (i.e., "hot spots") will also be excavated and incorporated there. Recyclable
materials from the surface debris piles will be recovered. An impermeable cap consistent with
RCRA Subtitle C reguirements will be installed over the ordnance area and consolidated wastes.
The cap will reduce any possible exposure to contaminants in the waste disposal area and will
reduce infiltration of precipitation into the wastes.

This remedy is consistent with long-term remedial goals for Site 2. The remedial action will help
to contain the waste on-site, thereby reducing the principal threat from potential contact with
ordnance materials. The remedy will also address direct contact and ecological risks posed from
exposure to soils and surface debris and ordnance-contaminated materials. The remedy will not
address surface water and sediment in Gambo Creek adjacent to Site 2. Remediation of these
media will be deferred to the Gambo Creek Ecological Study.

2.4 SUMMARY OF SITE CHARACTERISTICS

The RI at Site 2 was completed in phases. Geophysical investigations and radiologic
investigations were initiated in 1993. Sampling activities, consisting of soil sampling, surface
water and sediment sampling of Gambo Creek adjacent to Site 2, and the installation and
sampling of groundwater monitoring wells, were completed in 1994. Additional RI sampling,
consisting of additional surface and subsurface soil sampling and test pitting activities were
completed in 1996 and early 1997. The results of the RI are summarized below.

2.4.1 Sources of Contamination

Geophysical investigations at Site 2 included magnetic and surface radiological surveys. The
surveys were used to determine locations of buried ferromagnetic materials outside of the fenced
area and to evaluate the potential presence of thorium-contaminated surface soils. The results
of the survey outlined areas of buried metallic objects at Site 2 and identified four potential
source areas in addition to the fenced ordnance burial area (Figure 2-3). These included the
two trench disposal areas (Western and Southern Trenches) and the two surface debris piles
(Western and Southern Debris Piles) located on the site. Figure 2-4 indicates the estimated area
of soil contamination above Preliminary Remediation Goals (PRGs).

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2.4.2 Description of Contamination

Wastes in the fenced area of the site have never been sampled and analyzed due to presence of
ordnance and the potential dangers associated with their sampling. Based on historical records
and dimensions of the filled ordnance area, approximately 6,700 cubic yards of ordnance-
contaminated wastes are present in the fenced area of Site 2.

During the RI, surface and subsurface soil samples were collected at Site 2 and analyzed for
volatile organic compounds (VOCs), semivolatile organic compounds (SVOCs), pesticides,
PCBs, inorganics, explosives, thorium, radioactive gross alpha and beta activity, phenol and cyanide.

Surface Soils

VOCs were detected infreguently in the 12 surface soil samples collected. Acetone was
detected at its highest concentration of 130.0 Ig/kg, and styrene was detected at 35.0 Ig/kg in
one sample (SS2-5). Similarly, SVOCs were detected infreguently, with the majority of PAH
compounds being detected in a single sample (SS2-10) . The pesticides 4,4'-DDD, 4,4'-DDE.
and 4,4'-DDT were also detected in some samples at low levels, with 4,4'-DDT detected at the
highest concentration at SS2-8 (60 Ig/kg) in the debris piles on the West side of the site. These
pesticide concentrations were all below the corresponding risk-based concentrations (RBCs).
With respect to the protection of human health and ecological receptors, no VOCs and only one
SVOC (2-methylnaphthalene) were identified as contaminants of concern in surface soils at Site 2.

No explosives were detected in any of the surface soil samples. The radioactive parameter
analyses, for gross alpha and beta activity, detected a single sample that exceeded background
levels for Thorium-230. However the exceedance was slight (less than 3 times background).
Aluminum, antimony, arsenic, chromium, iron, mercury, thallium, vanadium, and zinc were the
only inorganics selected as contaminants of concern (COCs) in surface soils due to their
potential impact to ecological receptors. Antimony was included even though the highest
concentration detected was below the PRG, because the analytical result was reported as
biased low and was close to the PRG for the protection of sediments.

Subsurface Soils

Subsurface soil samples were collected from the waste disposal trenches, debris piles, and other
areas of the site. In addition, four test pits were completed through the trench disposal areas and
samples were collected for chemical analysis.

Similar to the results for surface soils, VOCs, SVOCs and pesticides/PCBs were typically
detected infreguently in the 62 samples and then at low concentration. No organic COCs were
identified in subsurface soils. Elevated levels of inorganics were, however, detected at Site 2
and antimony (20.8 Ig/kg maximum), arsenic (18.7 Ig/kg maximum), manganese (177 Ig/kg
maximum), selenium, (4 Ig/kg maximum) and vanadium (118 Ig/kg maximum) were selected
as potential COCs in subsurface soils due to the Potential for these constituents to migrate to
surface water and sediment.

Groundwater

A total of five monitoring wells were installed at Site 2 (Figure 2-3). The wells were sampled to
provide a comprehensive picture of groundwater guality at the site, and were analyzed for VOCs,
SVOCs, explosives, thorium, radioactive gross alpha and beta activity, pesticides, PCBs, and
inorganics (metals and cyanide).

Groundwater analytical data, both historical (1993) and most recent (1996), is presented in Table
2-1. Although low levels of VOCs, SVOCs and radioactive gross alpha and beta activity were
detected in groundwater samples collected, their detection at low levels was not indicative of
significant (action or maximum contaminant) levels of groundwater contamination.

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                                                                      TABLE 2-1
                                                         COMPARISON OF GROUNDWATER DATA
                                                       SITE 2, FENCED ORDNANCE BURIAL AREA
                                                           NSWCDL, DAHLGREN, VIRGINIA

                                                    Historical Data
                                                                                                              1996 Data
       Chemical
VOCs
Chioromethane
Methylene chloride
SVOCs
1,2-Dichlorobenzene
1,3-Dichlorobenzene
1,4-Dichlorobenzene
2-Chlorophenol
2-Methylphenol
4-Methylphenol
Bis(2-chloroethyl)ether
Bis (2-chloroisopropyl)ether
Bis(2-ethylhexyl)phthalate
Di-n-butylphthaiate
Diethyl phthalate

Fluorene
N-Nitroso-di-n-propylamine
Phenol
Inorganics
Aluminum
Aluminum, Filtered
Arsenic
Barium
Barium, Filtered
Cadmium
Calcium
Calcium, Filtered
Chromium
Chromium, Filtered
Cobalt
Cobalt, Filtered
Copper
Copper, Filtered


Frequency
of
Detection
0/3
0/3
1/3
1/3
1/3
1/3
1/3
1/3
1/3
c 1/3
0/3
2/3
1/3

0/3
1/3
1/3
3/3
3/3
0/3
3/3
3/3
0/3
3/3
3/3
2/3
0/3
3/3
3/3
2/3
2/3


Range of
Detection
(mg/L)
NA
NA
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
NA
0.6 - 0.7
1

NA
7.5
7.5
834.5 - 3170
56.5 - 143
NA
71.15 - 175
59.75 - 129
NA
2900 - 6770
2945 - 6030
4.9 - 5.3
NA
10.0 - 24.7
9.4 - 24.05
6.6 - 19.5
2.1
Mean of
Detected
Values
(mg/L)

NA
NA
7.5
7.5
7.5
7.5
7.5
7.5
7.5
7.5
NA
0.65
1

NA
7.5
7.5
1861.5
89.6
NA
110.5
83.9
NA
5036.7
4615
5.1
NA
16.7
15.9
13.1
2.1


Location of
Maximum

NA
NA
GW2-4
GW2-4
GW2-4
GW2-4
GW2-4
GW2-4
GW2-4
GW2-4
NA
GW2-3
GW2-1

NA
GW2-4
GW2-4
GW2-3
GW2-4-F
NA
GW2-3
GW2-1-F
NA
GW2-3
GW2-3-F
GW2-3
NA
GW2-4
GW2-4-F
GW2-3
GW2-1-F


Frequency
of
Detection
1/5
2/5
0/5
0/5
0/5
0/5
0/5
0/5
0/5
0/5
2/5
0/5
2/5

1/5
0/5
0/5
5/5
4/5
1/5
5/5
5/5
2/5
5/5
5/5
4/5
1/5
4/5
4/5
5/5
2/5


Range of
Detection
(mg/L)
6
49-51
NA
NA
NA
NA
NA
NA
NA
NA
0.65-1
NA
0.5

0.6
NA
NA
729 - 10720
22.1 - 1630
5.75
45.9 - 148
27.9 - 1127*
1.0 - 1.1
2000 - 7930
1330 - 7660
3.5 - 16.4
2.4
5.55 - 29.4
1.85 - 220
4.2 - 13.1
3 75 - 5.9

Mean of
Detected
Values
(mg/L)
6
50
NA
NA
NA
NA
NA
NA
NA
NA
0.83
NA
0.5

0.6
NA
NA
3829.8
474
5.75
89.8
63.1
1.05
3946
3228
7.5
2.4
13.4
9.8
7.5
4.8


Location of
Maximum

GW2-5
GW2-4
NA
NA
NA
NA
NA
NA
NA
NA
GW2-4
NA
GW2-2
GW2-4
GW2-2
NA
NA
GW2-2
GW2-5-F
GW2-2
GW2-3
GW2-3-F
GW2-2
GW2-5
GW2-5-F
GW2-2
GW2-5-F
GW2-4
GW2-4-F
GW2-2
GW2-5-F
Risk-
Based
COG
Screening
Level Tap
Water
(ug/L)
1.4*
4.1*
27
54
0.44*
18
180
18
0.0092*
0.26*
4.8
370
2900

150
0.0096*
2200
3700*
3700
0.045*
260
260
1.8
NA
NA
18 (2)
18 (2)
220
220
150
150



Federal
MCL(Ig/L)
NA
5*
600
600
75
NA
NA
NA
NA
NA
6
NA
NA

NA
NA
NA
50 - 200* (1)
50 - 200* (1)
50
2000
2000
5
NA
NA
100
100
NA
NA
1300 (3)
1300 (3)

-------
TABLE 2-1
COMPARISON OF GROUNDWATER DATA
SITE 2, FENCED ORDNANCE BURIAL AREA
NSWCDL, DAHLGREN, VIRGINIA
PAGE 2 OF 2
                                                    Historical Data
                                                                                                              1996 Data
Frequency
of
Detection

0/3
3/3
3/3
2/3
0/3
3/3
3/3
3/3
3/3
3/3
3/3
3/3
3/3
3/3
3/3
0/3
0/3
3/3
3/3
3/3
3/3
1/3
3/3
Range of
Detection
(mg/L)

NA
929.5 - 2780
142 - 446
2.3 - 16.0
NA
3330 - 7370
3190 - 6710
39.05 - 153
38.55 - 146
12.7 - 30.95
11.8 - 31.8
1070 - 2400
1210 - 2310
4965 - 7930
4965 - 6860
NA
NA
50.1 -75.05
39.5 - 74.75
2.14 - 18.4
5.355 - 19.2
2.67
21 - 42
Mean of
Detected
Values
(mg/L)

NA
1873.2
243.3
9.2
NA
4760
4413.3
98.1
93.2
21.6
21.2
1741.7
1700
6721.7
5941.7
NA
NA


8.2
10.3
2.7
30.3
Location of
Maximum
GW2-3-F
NA
GW2-3
GW2-4-F
GW2-3
NA
GW2-3
GW2-3-F
GW2-3
GW2-3-F
GW2-4
GW2-4-F
GW2-3
GW2-3-F
GW2-1
GW2-1-F
NA
NA
GW2-4
GW2-4-F
GW2-3
GW2-3
GW2-4
GW2-3
Frequency
of
Detection

0/5
5/5
4/5
0/5
1/5
5/5
5/5
5/5
5/5
5/5
5/5
5/5
5/5
5/5
5/5
4/5
1/5
4/5
5/5




Range of
Detection
(mg/L)


686
40.9


1800
1185
32.4
253
4.6
3.6
923
803
7680
7015
3.1

45.
19.85





4.3
- 7155
- 1540
NA
5.725
- 5030
- 4600
- 157
- 154
- 39.1
- 28.8
- 2290
- 2660
- 12800
- 11400
- 18.8
2.5
1 -108
- 97.5




Mean of
Detected
Values
(mg/L)

4.3
3062.2
449.8
NA
5.7
3269
2773
70.7
61.3
16.4
12.4
1651.6
1546.7
9345
8805
8.3
2.5
63.1
53.2




Location of
Maximum

GW2-2
GW2-2
GW2-5-F
NA
GW2-2
GW2-3
GW2-3-F
GW2-5
GW2-5-F
GW2-4
GW2-4-F
GW2-3
GW2-3-F
GW2-1
GW2-1-F
GW2-2
GW2-5-F
GW2-4
GW2-5-F




Risk-
Based
COG
Screening
Level Tap
Water
(ug/L)

73
1100*
1100*
15* (3)
15* (3)
NA
NA
84*
84*
73
73
NA
NA
NA
NA
26
26
1100
1100
NA
NA
NA
NA
Federal
MCL(Ig/L)

200
300* (1)
300* (1)
15* (3)
15* (3)
NA
NA
50 (1)
50 (1)
100
100
NA
NA
NA
NA
NA
NA
5000 (1)
5000 (1)
15
NA
NA
NA
Chemical

Cyanide
Iron
Iron, Filtered
Lead
Lead, Filtered
Magnesium
Magnesium, Filtered
Manganese
Manganese, Filtered
Nickel
Nickel, Filtered
Potassium
Potassium, Filtered
Sodium
Sodium, Filtered
Vanadium
Vanadium, Filtered
Zinc
Zinc, Filtered
Radionuclides
Gross alpha  (pCi/g)
Gross beta (pCi/g)

Thorium-230  (pCi/g)
Miscellaneous
Hardness as CaC03
1 Secondary MCL.
2 Hexavalent chromium.
3 Action level.
* Indicates the value is exceeded by the maximum site concentration.
Blank space indicates no analyses was performed
NA Not applicable

-------
No explosives were detected in monitoring wells GW2-1 and GW2-3, and no pesticide, or PCBs
were detected in any of the groundwater samples.

To fully characterize the occurrence and distribution of inorganics, both unfiltered (representing
total) and filtered (representing dissolved) samples were collected and analyzed. Both are
necessary to evaluate contaminant mobility and bioavailability. The sample results indicated
that iron, manganese and aluminum exceeded secondary MCLs in unfiltered samples, and the
action level (15 Ig/kg, from the Safe Drinking Water Act) for lead was exceeded in one well
(GW2-3). The most recent sample of all monitoring wells, including GW2-3, did not detect lead.
In addition, Virginia Groundwater Standards, which are based on drinking water criteria, were
exceeded for zinc and cadmium.

Surface Water

Surface water samples were analyzed for VOCs, SVOCs, pesticides/PCBs, inorganics (metals
and cyanide), radioactive parameters (including thorium isotopes), and hardness. A trace (1
Ig/L) concentration of trichloroethene was the only VOC detected in the eight samples collected
from Gambo Creek adjacent to Site 2. Similarly, trace concentrations of di-n-butylphthalate (4
Ig/L) and Fenuron TCA (0.44 Ig/L) were detected at very low levels. Sixteen inorganics were
detected in the surface water samples, thirteen of which contained concentrations above
reported maximum background levels.

The RI identified gross beta radioactivity sample results above maximum background levels
(8,53 pCi/1) in seven of eight surface water samples ranging from 29.3 to 80.75 pCi/1. However,
two additional surface water samples were obtained in Gambo Creek near the disposal trenches
to evaluate the potential for the leaching of radioactive materials from the wastes into the
stream. Thonium isotopes and gross alpha activity were not detected in these two samples.
Both of these samples detected gross beta radioactivity below the federal MCL of 15 pCi/1.

Sediments

VOCs and SVOCs were detected at a maximum of only two out of eight samples and then at low
concentrations at isolated locations in sediments. Five VOCs were detected at four different
sampling locations in Gambo Creek adjacent to Site 2. The highest concentration (380 Ig/kg)
was for acetone, which was reported as biased high. Six SVOCs were detected from three
locations with the highest concentration (380 Ig/kg) reported for benzo(a)pyrene. A total of 6
Polynuclear Aromatic Hydrocarbons (PAHS) were detected for a combined maximum
concentration of 1005 Ig/kg. The debris pile present on the west side of the site may represent a
possible source of some of the SVOC compounds detected. Nine pesticides/PCBs were
detected in sediments, with concentrations ranging from 3.3 Ig/kg to 1,910 Ig/kg. Most of the
highest concentrations were detected in one sample west of the site. However, pesticides are
known to be present at low levels (7.6 to 29 Ig/kg) in environmental media throughout the
NSWCDL facility, and Site 2 is not believed to be a source. The Gambo Creek Ecological
Study, currently being performed, will determine the extent to which surface water and sediments
are impacted by facility operations and will make recommendations for addressing sediments
and surface water throughout the Gambo Creek watershed on the base.

Explosive constituents were not detected in any of the sediment samples collected. Inorganics
were detected in sediment samples, several of which were detected above background levels,
including antimony, arsenic, beryllium, chromium, iron, lead, magnesium, and manganese.
Potential remedial actions to address contributions from other sources at NSWCDL are being
evaluated separately under the Gambo Creek Ecological Assessment Study.

2.4.3 Contaminant Migration

Access to the ordnance burial area of the site is currently restricted by fences. Base workers
visit Site 2 infreguently, and do not enter the ordnance disposal area. The trench disposal area
and the surface debris piles may be accessed, however, potential exposure is expected to be
minimal. The migration of contaminants associated with the ordnance burial area has been
shown in the different phases of the RI to be minimal, and potential exposure would be similarly minimal.

COCs identified at Site 2 consist of inorganics in surface and subsurface soil that may present
risks to ecological receptors. These contaminants are expected to migrate via surface runoff or

-------
through soils by dissolution to groundwater, and transport by groundwater to receptors in surface
water and sediment. Migration pathways were considered in detail in the modeling effort
completed for the FS.

2.5 SUMMARY OF SITE RISKS

The human health and ecological risks associated with exposure to contaminated media at Site 2
were evaluated in the RI Report Addendum. The human health baseline risk assessment
evaluated the potential health risks which might result under current and future industrial land
use scenarios. The residential use scenario was not evaluated and institutional controls will be
implemented to limit the site to future industrial use and exclude shallow groundwater use.
Under the industrial land use scenario for Site 2, COCs were selected by comparing the
contaminants detected to industrial risk-based concentrations. Due to its brackish quality and
productivity constraints, groundwater in the shallow aguifer is not a current source of drinking
water and will not be used as one in the future. Exposure to surface water is expected to be
limited to fishermen in boats in Gambo Creek.

An ecological evaluation was also performed to evaluate potential threats to ecological
receptors. A summary of the human health and ecological risks associated with the site is
presented below.

Because many contaminants have the ability to migrate from on medium to another (e.g, soil to
aroundwater), assessing risks from observed levels of contaminants is insufficient to evaluate all
the risks that may be presented at a site. Fate and transport modeling was therefore completed
to determine if levels of COCs might migrate to other media and present unacceptable future
risks to potential receptors. Preliminary Remediation Goals (PRG's) were developed for COCs
in all media to establish concentrations that would not produce unacceptable risks.

2.5.1 Human Health Risks

Exposure Pathways and Potential Receptors

Base workers, recreational users (adults and children, on the site and on Gambo Creek adjacent
to Site 2), and construction workers were evaluated as potential receptors in the quantitative risk
assessment. Construction workers were evaluated for future conditions only. The remaining
receptors are considered for current and future conditions. Ingestion of finish was evaluated for
adult recreational users only. Construction workers were evaluated for exposure to
surface/subsurface soil (0 to 12 feet), while surface soil (0 to 2 feet) exposure was considered for
all other receptors. Inhalation of volatile emissions and fugitive dust was evaluated qualitatively
via a comparison of site data to EPA Generic Soil Screening levels for transfers from soil to air.
Inhalation exposure was considered to be relatively insignificant since all detected soil
concentrations were less than the screening levels. Direct contact with surface water and
sediment is not anticipated at the site. Fishermen will be in boats and have very limited
exposure and duration of exposures to surface waters. Therefore, pathways associated with
these media were not quantitatively evaluated.

Exposure Assessment

No VOCs were identified as COCs in the surface or subsurface soil at Site 2. Arsenic at a
maximum concentration of 18.7 mg/kg was evaluated in surface and subsurface soils. All the
other inorganics identified as COCs in surface and subsurface soils are listed because of
environmental risks. These inorganic COCs all had concentrations below the human health risk
based concentrations (RBCs). Antimony and iron were identified as COCs for the exposure
assessment from fish ingestion.

Toxicity Assessment

Cancer potency factors (CPFs) have been developed by EPA's Carcinogenic Assessment Group
for estimating excess lifetime cancer risks associated with exposure to potentially carcinogenic
chemicals. CPFs, which are expressed in units of (mg/kg-day) -1, are multiplied by the estimated
intake of a potential carcinogen, in mg/kg-day, to provide an upper-bound estimate of the excess
lifetime cancer risk associated with exposure at that intake level. The term "upper bound"
reflects the conservative estimate of the risks calculated from the CPFs. Use of this approach

-------
makes underestimation of the actual cancer risk highly unlikely. Cancer potency factors are
derived from the results of human epidemiological studies or chronic animal bioassays to which
animal-to-human extrapolation and uncertainty factors have been applied.

Reference doses (RfDs) have been developed by EPA for indicating the potential for adverse
health effects from exposure to chemicals exhibiting noncarcinogenic effects. RfDs, which are
expressed in units mg/kg-day, are estimates of lifetime daily exposure levels for humans,
including sensitive individuals. Estimated intakes of chemicals from environmental media (e.g.,
the amount of a chemical ingested from contaminated drinking water) can be compared to the
RfD. RfDs are derived from human epidemiological studies or animal studies to which
uncertainty factors have been applied (e.g., to account for the use of animal data to predict
effects on humans). These uncertainty factors help ensure that the RfDs will not underestimate
the potential for adverse noncarcinogenic effects to occur.

Risk Characterization

Excess lifetime cancer risks are determined by multiplying the intake level with the cancer
potency factor. These risks are probabilities that are generally expressed in scientific notation
(e.g., 1x10 -6). An excess lifetime cancer risk of 1 x 10 -6 indicates that, as a plausible upper
bound, an individual has a one in one million chance of developing cancer as a result of site
related exposure to a carcinogen over a 70-year lifetime under the specific exposure conditions
at a site.

Potential concern for noncarcinogenic effects of a single contaminant in a single medium is
expressed as the hazard guotient (HQ) (or the ratio of the estimated intake derived from the
contaminant concentration in a given medium to the contaminant's reference dose). By adding
the HQs for all contaminants within a medium or across all media to which a given population
may reasonably be exposed, the Hazard Index (HI) can be generated. The HI provides a useful
reference point for gauging the potential significance of multiple contaminant exposures within a
single medium or across media.

Current and Future Bass Worker. The cumulative hazard indices for ingestion of and dermal
contact with soils for Site 2, under industrial land use conditions are less than 1, which indicates
that there are no significant hazards associated with soils at Site 2. The cumulative ingestion
and dermal contact cancer risk is 1.3 x 10 -7 under a "reasonable maximum exposure" scenario,
well below EPA's target risk range of 1 x 10 -6 to 1 x 10 -4.

Adult Recreational User. The cumulative noncancer hazard index from exposure via ingestion
of and dermal contact with Site 2 soils, under industrial land use conditions are less than 1, as is
the risk associated with the potential ingestion of fin fish. The cumulative ingestion and dermal
contact cancer risk is 6.4 x 10 -7 under a reasonable maximum exposure scenario, well below
EPA's target risk range of 1 x 10 -6 to 1 x 10 -4 . Under the industrial land use scenario, ingestion
and dermal contact were evaluated just for arsenic.

Child Recreational User. The cumulative hazard index and cancer risk associated with
ingestion and dermal contact exposure to surface and subsurface soil at Site 2 under industrial
land use scenario are 2.4 x 10 -2 and 1.4 x 10 -6 respectively under a reasonable maximum
exposure scenario. Under the industrial land use scenario, ingestion and dermal contact were
evaluated just for arsenic.

Construction Worker. The cumulative hazard index and cancer risk associated with ingestion
and dermal contact exposure to Site 2 soil under industrial land use conditions are 8.4 x 10 -2 and
5.4 x 10 -7 respectively under a reasonable maximum exposure scenario.

Although the incremental cancer risk (ICR) for the child recreational user slightly exceeded 1 xlO -
5, it is well within EPA's target risk range of 1 x 10 -4 to 1 x 10 -6. Since the ICR to all other
receptors is less than 1 x 10 -6, and the hazard indices for receptors are less than 1.0, human
health risks under industrial land use conditions are within acceptable risk ranges at Site 2.
Human health baseline risks are not greater than the risk range, however action is being taken at
Site 2 to protect potential environmental receptors.

There are several aspects of uncertainty associated with the risk assessment conducted at Site
2. The major issues of uncertainty specific to Site 2 are as follows:

-------
While the USEPA recognizes lead as a B2 carcinogen, no cancer slope factor has been assigned
to this chemical. Currently, risks associated with lead are estimated in terms of predicted blood
lead levels in small children (ages 7 and under) by using the Integrated Uptake Biokinetic Model.
Typically, lead does not become a significant risk factor unless concentrations exceed 400 mg/kg
in soil (USEPA, 1994b) and 15 Ig/L in drinking water. Lead is not considered to be a COG for
soil at the site since the maximum detected concentration of lead is less than 400 mg/kg.
Although the maximum site concentration of lead in groundwater exceeds 15 Ig/L, groundwater
is not expected to be used as a potable water supply. No USEPA Region III COG screening
level is available for exposure to lead in fish. However, the maximum surface water
concentration for this chemical (7.0 Ig/L; sample SW2-7) was well below the 50 Ig/L Federal
AWQC for the protection of human health (consumption of water and organisms). Therefore,
even though lead was not evaluated quantitatively in the human health risk assessment, the
potential risks associated with exposure to this chemical are considered to be minimal.

Because of the lack of toxicity criteria, USEPA Region III COG screening levels could not be
calculated for a few chemicals detected in the soil and surface water at the site
(benzo(g,h,i)perylene, calcium, magnesium, sodium, and potassium). This may lead to a slight
underestimation of potential risks. However, the underestimation is expected to be minimal
since overall exposure to PAHs is adequately addressed by the evaluation of other PAHs, and
the remaining inorganics are essential nutrients, commonly detected in environmental media.

Because of the relatively small data set of five samples, the maximum surface water
concentration was used to assess potential RME risks for recreational users via fish ingestion.
Consequently, the human health risks, associated with this exposure route may be overestimated
since it is highly unlikely that the true exposure concentration for surface water, to which a
receptor is hypothetically exposed over the entire exposure period, is equal to the maximum detection.

Analytical results for unfiltered surface water samples were used to estimate potential human
health risks for fish ingestion. Unfiltered results are typically greater than filtered results because
of suspendel sediment. The use of unfiltered data is considered to be conservative since data
for filtered samples are more likely to approximate the bioavailable fraction of inorganics in
surface water. Therefore, estimates of fish uptake based on unfiltered sample data for
inorganics may result in overestimates of fish tissue concentrations and the human health risks
for fish consumption.

The calculated risks for the fish ingestion pathway are based on estimates of uptake from
surface water and do not account for the uptake of contaminants from sediment. Thus, the risks
for the fish ingestion pathway may be underestimated. Chemicals present in the sediment, as
opposed to the surface water, may be of greater concern for bioaccumulation in fish. Chemicals
commonly detected in the sediment at Site 2 consist of PAHs and metals. Styrene was detected
in one sediment sample. A presentation of the sediment results for the site is provided in the
Draft RI Report, Volume I.

2.5.2 Environmental Evaluation

The intent of the baseline ecological risk assessment (ERA) was to characterize potential
receptors and to estimate the potential hazard or risk to environmental receptors. Contaminant
pathways were identified to evaluate receptors potentially at risk. The EPA followed EPA
guidance for performing ecological risk assessments and was approved by Region III, EPA's
Biological Technical Assistance Group (BTAG). The baseline ERA is described fully in the RI
Report, and is briefly summarized here.

Analytical data compiled from the RI were analyzed using EPA Region III guidance for
screening-level risk assessments and to determine environmental effects quotients (EEQs).
EEQs were determined by comparison with standard guidelines such as EPA Region III and
Biological Technical Assistance Group (BTAG) guidelines. Data were reviewed for surface
water, sediment, and surface soil; preliminary COCs (PCOCs) were selected for each of these
exposure media by comparing maximum site concentrations to screening values, which typically
are conservative. COCs were selected by comparing maximum site concentrations to
preliminary remediation goals (PRGs). Those chemicals exceeding PRGs and potentially posing
an actual risk to receptor populations living on or near Site 2 were selected as COCs. Decisions
regarding whether or not to remediate a contaminant or how to manage the potential risk were
made by comparling maximum site concentrations to background levels, and by considering the

-------
frequency of detection, the likelihood that a source exists on the site, and bioavailability.

The PCOCs for surface water were di-n-butyl phthalate, aluminum, copper, iron, manganese,
and nickel. Because all of the metals were detected at levels above PRGs, they were retained
as COCs for surface water.

Of the twenty-two PCOCs identified in sediment, nine had maximum concentrations above their
PRG (or had no PRG), and were retained as COCs for sediment. The nine COCs were acetone,
methylene chloride, styrene, endrin aldehyde, heptachlor, monuron, aluminum, antimony, and iron.

There were thirty-three PCOCs in surface soil, including 15 PAHs and 14 metals. Nine metals
and one PAH had maximum concentrations above PRGs (or had no PRG) and were carried
forward as COCs. These were 2-methylnaphthalene, aluminum, antimony, arsenic, chromium,
iron, mercury, thallium, vanadium, and zinc.

Table 2-2 summarizes the list of COCs developed for the ecological risk assessment.

2.5.3 Development of Preliminary Remediation Goals (PRGs)

Contaminant fate and transport modeling is used to evaluate the potential for COCs identified by
the human health and ecological risk assessment to migrate to other media and present
unacceptable risks. For example, contaminants present in soils could migrate to groundwater or
be carried with precipitation to surface water or sediments at a site. In order to evaluate this
potential, fate and transport modeling was conducted for Site 2 using the ECTran model.

The model uses contaminant properties such as solubility, and site specific characteristics such
as depth to groundwater, to predict acceptable levels of COCs in soil and groundwater that would
be protective of surface water and sediment. Using regulatory criteria for surface water and
similarly protective sediment, values for the concentrations developed by the modeling, PRGs,
are used to determine if existing levels of COCs are acceptable. A complete discussion of the
use of modeling and assumptions is presented in the Site 2 FS.

Potential migration of COG's evaluated for Site 2 by the ECTran model included:

• Surface soil to surface water via runoff
• Surface soil to sediment via runoff
• Surface soil to surface water via groundwater
• Subsurface soil to surface water via groundwater
• Subsurface soil to sediment via groundwater
• Groundwater to surface water
• Groundwater to sediment

PRGs were developed by modeling for the following COC's:

• Antimony
• Arsenic
• Beryllium
• Chromium
• Copper
• Lead
• Manganese
• Nickel
• Vanadium

This list includes COCs identified by the human health risk assessment and most of the metals
identified as COCs in the ecological risk assessment. The COCs that were not modeled were;
not attributable to Site 2 as a current source, or had borderline toxicity potential, or were
common laboratory contaminants, or had concentrations no different from background levels.
Copper was identified by the modeling to be present in surface soils at levels slightly above the
PRG for the protection of surface water (via groundwater) at one location. Vanadium was
identified at levels in subsurface soils exceeding the PRG for the protection of sediment at
3 locations. Concentrations of the contaminants of concern in each medium of exposure are
found in Tables 2-3, 2-4, and 2-5.

-------
                                         TABLE 2-3

                       SUMMARY OF SURFACE SOIL PRGs - SITE 2 - (mg/kg)
                                NSWCDL DAHLGREN,  VIRGINIA
                                  Soil Sampling
                                       Results
                                                              Preliminary Remediation Goals
                                           Protection of
                            Detected Values    Surface Water
        Chemical of         Range  of
         Concern
Inorganics - total metals
Antimony                       12.8-21.45       375
Arsenic                         1.3-5.1         307
Beryllium                      0.35-0.81       71.1
Chromium                        7.8-19.2       46.6
Copper                         3.7-19.9        409
Lead                           5.8-43.5         313
Manganese                      6.4-191.5      1,500
Nickel                          2.5-8.25        104
Vanadium                       13.2-31.8      2,730
Protection of
  Sediment

   27.6
   77.4
   1.26
    409
   298
    241
    475
   57.0
   40.9
Shaded:
          COG which exceeds PRGs

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                                      TABLE 2-4
                   SUMMARY OF SUBSURFACE SOIL PRGs - SITE 2 - (mg/kg)
                            NSWCDL DAHLGREN, VIRGINIA
Chemical of
 Concern
Soil Sampling Results

       Range of Detected
           Values
                                                       Preliminary Remediation Goals
Protection of
 Surface Water
Protection of
Sediment
Inorganics (total metals)
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Manganese
Nickel
Vanadium
0.052-21.45
0.93-18.7
0.18-0.85
3.0-61.3
2.8-27.1
0.08-43.5
2.9-191.5
1.2-11.8
3.9-118
                                                        6,340
                                                        3,180
                                                       42,400
                                                          422
                                                          372
                                                       63,900
                                                       31,300
                                                        3, 640
                                                     ,000,000
                                                                 53.1
                                                                  149
                                                                  2.4
                                                                 793
                                                                 574
                                                                  460
                                                                912
                                                                109
                                                               77.0
 Shaded:
              COG which exceeds  PRGs

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                                     TABLE 2-5

                     SUMMARY OF GROUNDWATER PRGs - SITE -  (Ig/L)
                           NSWCDL DAHLGREN, VIRGINIA

                                                  Preliminary Remediation Goals

Chemical of Concern  Range of Detected          Protection of        Protection of
                            Values              Surface Water           Sediment

Inorganics  (total and dissolved metals)

Arsenic                        5.75                65,500              3,030
Chromium                     2.4-16.4               13,200            24,700
Copper                       2.  -19.5                6,340             9,830
Lead                        2.3-16.0               143,000             1,020
Manganese                    25.3-157              378,000             10,200
Nickel                       3.6-39.1               33,800              1,000
Vanadium                     2.5-18.8            >1,000,000              40.5

Exposure Pathways

The terrestrial exposure pathways include: dermal absorption of chemicals from soil, ingestion of
soil, absorption of chemicals from soil by plants, and ingestion of chemicals through the food
chain.  Exposure to contaminants for aguatic receptors in Gambo Crook may occur via ingestion
of contaminated surface water, sediment, and food, and through direct contact with surface water
and sediments.

Exposure Assessment

Surface soil contaminants at Site 2 that had EEQs greater than 1, or had no PRG, included 2-
methyl napthalene, aluminum, antimony, arsenic, chromium,  iron, mercury, thallium, and
vanadium.  The EEQs related to other chemicals were all less than or egual to 1, indicating that
the risks for those chemicals were near or within acceptable ranges.

Potential Receptors

Terrestrial organisms most likely to be receptors include: soil microrganisms, soil invertebrates,
mammals, and birds.  In addition, due to the proximity of Gambo Creek to Site 2, a variety of
freshwater and estuarine organisms are potential receptors.  Because of the natural setting of
Site 2 and the variety of nearby habitats, Site 2 is likely to have a diversity of wildlife.

Risk Characterization

Based on risk management factors as well as hazard potential, antimony in surface soils, copper
in surface water, and pesticides and the herbicide monuron in sediment are of concern for risks
to ecological receptors at Site 2.  Risk management factors include comparing maximum site
concentrations to background levels, considering the freguency of detection, the likelihood that a
source exists on the site, and bioavailability of the contaminant.

2.5.4         Assessment of Site 2 Risk

In summary, human health risks were evaluated to be within acceptable ranges.  Ecological risks
were identified for antimony, copper, pesticides, and monuron.  Based on the analysis performed
in the FS for Site 2, antimony was identified at levels above PRGs for protection of ecological
receptors at two locations, and copper at one location in surface soils.  In addition, vanadium
was identified above PRGs at three locations in subsurface soils.  Pesticides and monuron in
sediments of Gambo Creek adjacent to Site 2 will be evaluated further in the Gambo Creek
Ecological Study and any necessary remedy selected thereafter.

Viewed within the context of the full range and distribution of sample results throughout the site,
these exceedances were considered isolated "hot spots"  (see Figure 2-4) that would be
addressed as part of the remedial altenatives considered for Site 2.

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2.6           DESCRIPTION OF ALTERNATIVES

Based on an evaluation of site conditions, potential risks, and legal requirements for Site 2, four
remediation goals were identified to protect the public from potential current and future health
risks, as well as to protect the environment:

       •      Compliance at Site 2  with contaminant-specific,  location-specific,  and action-specific
              Federal and Commonwealth of Virginia ARARS,  and to be considereds (TBCS).

       •      Protect human receptors from contact with ordnance material which is suspected to
              be buried in the southern half of the fenced area.

       •      Prevent antimony at concentrations greater than 5mg/kg in surface soils from
              contact with terrestrial ecological receptors and causing adverse effects.

       •      Prevent copper at concentrations greater than 15.5 mg/kg in surface soils  from
              migrating to surface water and vanadium at concentrations greater than 77  mg/kg in
              subsurface soils from migrating to sediments, and causing adverse effects  in
              ecological receptors.

A detailed analysis of the possible remedial atternatives for Site 2 is included in the Site 2
Feasibility Study (FS) report.  The detailed analysis was conducted in accordance with the EPA
document entitled "Guidance for Conducting Remedial Investigations and Feasibility Studies
under CERCLA" and the National Oil and Hazardous Substances Contingency Plan  (NCP).

Institutional controls, including a real property description notation.  Base Master Plan notations,
and limited site access would be implemented for each alternative except the No Action Alternative.

Limited site access would be achieved by using fencing and by posting signs that say hazardous
wastes are present.   The Base Master Plan will note the area as one in which construction
changes can not occur, residential development can not occur, shallow groundwater can not be
used, and site access will be limited.  A notation will be filed in the real property file maintained
by EFA Ches for this site indicating the extent of the area and the fact that hazardous wastes are
present.  Institutional controls shall also include the following: Within 60 days of closure
(capping),  the Navy shall produce a survey plat indicating the location and dimensions of landfill
cells or other hazardous waste disposal units with respect to permanently surveyed benchmarks.
This plat shall be prepared and certified by a professional land surveyor.  The plat shall contain a
note, prominently displayed, which states the owner's obligation to restrict disturbance of the
hazardous waste disposal unit: post-closure use shall prohibit residential use, shall prohibit
access or use of groundwater underlying the property for any purpose except monitoring,  and
shall never be allowed to disturb the integrity of the final cover, liners, or any other components
of the containment system, or the function of the facility's monitoring systems.  No later than 60
days after closure,  the Navy shall submit to the county board of supervisors a record of the type,
location, and quantity of hazardous wastes disposed of within each cell or other disposal unit of
the facility.  As soon as practicable, the owner shall record, in accordance with state and local
law, a notation on the deed to the property - or on some other instrument which is normally
examined during title search - that will in perpetuity notify any potential purchaser of the property
that the land has been used to manage hazardous wastes, that its use is restricted as described
above, and that a survey plat and a record of the type, location, and quantity of hazardous
wastes disposed of have been filed with the local government.  If and when the property is
transferred out of the federal government, the deed shall contain the survey plat, the notation
that the property was previously used to manage hazardous wastes and that its future use is
restricted, and other deed restrictions as appropriate.  Reviews of groundwater, surface water,
sediment and drainage system monitoring would be conducted every 5 years for each
alternative.  Due to Navy security concerns with the nature of the material in the disposal
trenches at Site 2,  the FS did not consider any offsite treatment or disposal alternatives for waste
buried in these trenches.  Similarly, due to safety concerns for ordnance-related waste in the
fenced ordnance area, the FS did not consider any alternatives that would require the excavation
of this portion of the site.

A summary of the remedial alternatives which were developed to address contamination
associated with Site 2 is presented below.

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ALTERNATIVE 1 - No Action

Description: Under this alternative no further effort or resources would be expended at Site 2.
Alternative 1 serves as the baseline against which the effectiveness of the other alternatives is judged.

ALTERNATIVE 2 - Remove Soils Exceeding Remediation Goals and Dispose Offsite;
Characterize and Take Appropriate Action on Western Debris Pile; Backrill with Clean Fill;
Institutional Controls

Description: Waste materials would be excavated from the areas where remediation goals are
exceeded, including the southern debris pile, and disposed at an offsite industrial landfill.
Although wastes present in the western debris pile have not been characterized as exceeding
remediation goals, the basis of the characterization is a single sample. Additional sampling of
the western debris pile would be completed to more completely characterize the materials
disposed in this area of the site, and to take appropriate action. No actions would be taken for
the western debris pile unless further characterization indicated that remediation goals were
exceeded. If remediation goals are determined to be exceeded, the guantity of soils that
exceeded remediation goals would be disposed in an industrial waste landfill (Alternative 2A).
Costs developed for Alternative 2A assume that if excavation proved to be necessary that all
soils in the western debris pile would reguire disposal. All areas of the site excavated to achieve
remediation goals would be backfilled with clean fill, regraded, and revegetated. No additional
actions are proposed for the fenced ordnance burial area under Alternative 2. During
excavation, the potential for erosion will be minimized by following erosion and sediment control
best management practices. Habitat alteration will be minimal.

Institutional controls including limiting site access and future land use would be implemented to
eliminate or reduce potential exposure to ordnance materials at the site. In addition,
groundwater, surface water, and sediment monitoring would be conducted over at least the next
five years to determine if contaminants were migrating at significant rates and concentrations.

The costs for this alternative are:

Capital costs* $396,000
Annual costs $26,800
30-year present worth* $876,000
Months to implement 4

*Note: Costs indicated assume that western debris pile characterization does not result in
exceeding remediation goals. If remediation goals are exceeded, capital costs for the alternative
(offsite disposal, Alternative 2A) are estimated to be $818,000 (present worth of $1,298,000).

ALTERNATIVE 3 - Remove Soils Exceeding Remediation Goals and Dispose Offsite or
Beneath Cap Onsite; Characterize and Take Appropriate Action on Western Debris Pile;
Backfill with Clean Fill; Cap Fenced Area and Western and Southern Trenches; Institutional Controls

Description: Alternative 3 is identical to Alternative 2, with the exception that the fenced area
and the western and southern disposal trenches would be capped resulting in a RCRA Subtitle C
Landfill Closure. No actions would be taken on the western debris pile unless further
characterization indicated that remediation goals were exceeded. If remediation goals were
determined to be exceeded, the guantity of soils that exceeded remediation goals would be
removed and either disposed in an industrial landifill (Alternative 3A) or removed and placed
beneath the cap covering the fenced area and the western and southern disposal trenches
(Alternative 3B). A multi-layer cap installed over the fenced area and trenches would minimize
the potential for human contact, and reduce the potential migration of contaminants through the
ordnance and trench disposal areas. Consistent with RCRA Subtitle C reguirements, the cap
would consist of a minimum of 24 inches of topsoil and vegetative cover underlain by a filter
layer and 12 inches of drainage (minimum 10 -2 cm/sec), a 20 mil geomembrane, and 24 inches
of compacted soil or clay achieving a maximum hydraulic conductivity of 10 -7 cm/sec. The
vegetative and protective layers provide stability and erosion control and protect underlying
layers. The drainage layer allows infiltrating surface water to flow away from the cap areas. The
geomembrane is a protective layer overlying the low permeability soil/clay cap. (See Section
2.8.1 for a more thorough discussion of the function and composition of the cap layers).

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During excavation and construction of the cap, the potential for erosion will be minimized by
following erosion and sediment control best management practices.  Less than one acre of forest
habitat will be converted to grassland habitat.

Institutional controls including limiting site access and future land use would be implemented to
eliminate or reduce potential exposure to ordnance materials at the site.  In addition,
groundwater, surface water, and sediment monitoring over the next 30 years would be conducted
to determine if contaminants from either the ordnance area or the disposal trenches were
migrating at significant rates and concentrations.  Because the elevation of the groundwater
table is not known relative to the buried materials in the fenced area, groundwater monitoring
would also be used to evaluate whether further actions were necessary to depress the
groundwater table to avoid communication with fenced area wastes.

The estimated costs for this alternative are:

Estimated capital costs*                $1,065,000
Estimated annual costs                        $26,000
Estimated 30-year present worth*         $1,545,000
Months to Implement                           12

*Note: Costs indicated assume that western debris pile characterization does not result in
exceeding remediation goals.  If remediation goals are exceeded, capital costs for the alternative
(offsite disposal; Alternative 3A) are estimated to be $1,550,000 (present worth of $2,030,000).

If the materials can be consolidated beneath the onsite cap (Alternative 3B), capital costs are
estimated to be $1,140,000  (present worth of $1,620,000).

ALTERNATIVE 4 - Remove Soils Exceeding Remediation Goals; Remove Western and
Southern Trenches and Debris Piles; Backfill with Clean Fill;  Consolidate All Removed
Wastes Onsite, Dispose of Recyclable Materials from Debris Piles Offsite; Cap Fenced
Area and Consolidated Soils; Institutional Controls

Description:  Alternative 4 is identical to Alternative 3 (more specifically Alternative 3B) with the
exception that wastes are removed from the western and southern trenches and consolidated
beneath an impermeable cap, rather than left in place and capped.  The intent of Alternative 4 is
to minimize the possibility of future groundwater communication with the trenched wastes and
potential subseguent leaching of associated contaminants.  This would be accomplished by
moving the wastes to ground surface for disposal and subseguent capping.  The capping area
and reguirements would be identical to that indicated by Alternative 3.

During excavation and construction of the cap, the potential for erosion will be minimized by
following erosion and sediment control best management practices.  Less than one acre of forest
habitat will be converted to grassland habitat.

Institutional controls including limiting site access and future land use would be implemented to
eliminate or reduce potential exposure to ordnance materials at the site.  Monitoring of
groundwater, surface water, and sediment would be performed as described in Alternative 3.

The estimated costs for this alternative are:

Estimated capital costs            $1,510,000
Estimated annual costs                  $26,000
Estimated 30-year present worth    $1,990,000
Months to Implement                     12


2.7           SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES

The remedial alternatives presented on 2.6 were evaluated in the FS against nine criteria
identified in the NCP.  The comparison alternative to the nine criteria is presented below.

2.7.1         Threshold Criteria

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Overall Protection of Human Health and the Environment

The Site 2 Remedial Action Objectives  (RAOs) include:

  Compliance at Site 2 with contaminant-specific, location-specific, and action-specific Federal
  and Commonwealth of Virginia ARARs, and TBCs.

  Protect human receptors from contact with ordnance material which is suspected to be buried
  in the southern half of the fenced area.

  Prevent antimony at concentrations greater than 5mg/kg in surface soils from contact with
  terrestrial ecological receptors and causing adverse effects.

  Prevent copper at concentrations greater than 15.5 mg/kg in surface soils from migrating to
  surface water and vanadium at concentrations greater than 77 mg/kg in subsurface soils from
  migrating to sediments, and causing adverse effects in ecological receptors.

Alternative 4 provides the highest level of protection because wastes in the western and southern
disposal trenches, including batteries known to contain lead, zinc, and manganes would be
excavated and brought to ground surface and capped, further reducing the potential for
contaminants to migrate to ecological receptors.  Institutional controls, including deed restrictions
and fencing, would prevent direct contact risks to ordnance materials in the fenced area.
Alternatives 3, 3A, and 3B would provide a measure of protectiveness by installing a cap over
the fenced area and disposal trenches, thereby reducing potential infiltration of precipitation to
the buried wastes and potential migration of contaminants.  Alternative 2 would be protective.
Soils exceeding remediation goals and posing risks to ecological receptors would be excavated
and removed from the site, if soils in the western debris pile were determined to exceed
remediation goals  (Alternative 2A), these soils would similarly be excavated and removed from
the site for appropriate disposal.  Institutional controls under Alternatives 2, 3, 3A, 3B, and 4,
including deed restrictions and long-term monitoring of groundwater, surface water, and
sediments, would limit the use of groundwater and any future use of the site to ensure overall
protection of human health and the environment.   Alternative 1 would not be protective of
ecological receptors, because no action would be undertaken to address soil contamination
posing risks to ecological receptors at Site 2.

Compliance with Applicable or Relevant and Appropriate Reguirements (ARARs)

Alternative 4 would comply with all ARARs and TBCs and in addition would follow the policy for
landfill closures to keep a minimum distance between wastes and the groundwater.  Alternatives
3, 3A, 3B would comply wdh all ARARs and TBCs identified.  Alternative 2 (and 2A)  would
comply with remediation goals for the protection of ecological receptors, however, it would not
address the recently promulgated Military Munitions Rule  (40 CFR 260)  or DoD guidance
(6055.9.STD) regarding disposition of property containing explosives or ordnance wastes.
Generally, the Military Munitions Rule provides a clarification of RCRA reguiring consideration
of ordnance wastes as hazardous.  DoD guidance supports the removal of ordnance wastes, if
practical, and its safe disposal otherwise.  Alternative 1 will not achieve remediation goals for
the protection of ecological receptors, nor meet all ARARs and TBCs.

2.7.2         Primary Ballancina Criteria

Long-Term Effectiveness and Permanence

Alternative 4 provides the most effective and permanent - protection because it provides for the
excavation of the wastes present in the western and southern trenches, including batteries, and
their disposal well above the groundwater table.  With the implementation of a RCRA Subtitle C
cap, Alternatives 3, 3A, 3B, and 4 would greatly reduce the potential for migration of
contaminants from the fenced ordnance burial area and the trench disposal areas, and would
therefore provide an effective and permanent protection of human health and the environment.
Alternative 2  (and 2A) does not provide for the installation of an impermeable cap, and would
therefore not provide the same degree of effectiveness.  In addition,  inorganics,  including
batteries known to contain lead, zinc, and manganese, would remain on site under Alternative 2
(and 2A).  Alternative 1 would not be effective in the long term because there would be no
means available to evaluate effectiveness over time.

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Reduction of Toxicity, Mobility, and Volume

Alternative 4 has the greatest potential to reduce the mobility of contaminants. Excavation of
the wastes in the disposal trenches and bringing the wastes to the ground surface prior to
capping, thereby removing them from contact with the water table and increasing the buffer
between the wastes and the groundwater, and provides the additional reduction in the potential
mobility of the contaminants into the groundwater. Alternative 4 would reduce the volume of
wastes by removal and consolidation of some wastes. Alternatives 3, and 3A would reduce the
mobility and volume of soil contaminants at the site, however, offsite disposal would merely
relocate the wastes. Similarly, Alternative 3 would not reduce the volume or toxicity of the
wastes, but would reduce their mobility through the installation of a RCRA Subtitle C cap over
the fenced area and disposal trenches. Alternatives 2 and 2A would reduce the mobility and
volume of soil contaminants at the site, however, offsite disposal would merely relocate the
wastes. Alternatives 2, 3, 3A, 3B, and 4 would provide the potential for recycling or reclaiming
materials present in the western, and southern debris piles which would reduce the volume of
materials that would otherwise reguire disposal. Alternative 1 would not achieve any reduction of
toxicity, mobility, or volume of contaminants at Site 2.

Short-Term Effectiveness

Alternative 4 would have the best potential for short-term effectiveness to address RAOs.
Alternative 4, while having some additional concerns relative to potential worker exposures
during excavation of the disposal trenches, would address these concerns with appropriate
personal protective eguipment and site monitoring, and will be accomplished within a relatively
short time frame. Alternative 4 would provide a more permanent remedy upon completion that
would address all RAOs. The potential risk from explosion during capping of the landfill will be
reduced by providing an additional soil layer to reduce the load during construction. Alternatives
2, 2A, 3 and 3A would have additional concerns associated with potential exposures during
offsite transport of contaminated soils. To reduce this potential exposure transport vehicles will
be covered. Alternative 3B would not address the batteries and other wastes present in the
western and southern disposal trenches. Alternative 1 would not be effective in the short-term
because soils exceeding remediation goals are left in place.

Implementability

Alternative 4 is the best choice for implementation and site remediation. The installation of a
RCRA Subtitle C cap under Alternatives 3, 3A, 3B and 4 would have some implementation
concerns related to construction of the cap over the fenced ordnance area of the site. The
construction of the cap will reguire special construction technigues or methods to cap the fenced
area safely and effectively. Safety concerns provide for a somewhat more complex remedy
under Alternatives 3, 3A, 3B, and 4. However, these concerns can be easily addressed by
applying prudent health, safety, and construction measures, and capping is a well demonstrated
technology that has been shown to be reliable and readily implementable using conventional,
commercially available materials and eguipment. The excavation of wastes under Alternative 4
would also add some concern due to increased excavation and waste handling reguirements,
however, these concerns would be addressed through the implementation of appropriate health
and safety measures, and would be easily implemented.

Alternatives 3, 3A, and 3B involve off-site removal of wastes which will reguire additional testing,
logistical support, and will increase local street traffic. Alternatives 2 and 2A would have the
fewest implementability concerns, however, this is because relatively little would be necessary to
be performed under either alternative. Alternative 1 reguires no implementation.

Cost

Alternative 4 provides the most cost-effective remedy for Site 2. Alternative 4 provides the
highest level of protectiveness and addresses all ARARs and TBCs for the site. Although not the
least costly alternative, the increased environmental benefits associated with removing the
batteries from the trenches for disposal at higher elevation compensates for the additional cost
of approximately $445,000 over Alternative 3. Based on estimated net present worth, of the
alternatives that employ active remediation Alternative 2 is the least expensive remedy
($876,000), followed by Alternative 2A ($1,298,000). However, as mentioned previously, these
alternatives may not address all ARARs and TBCs for Site 2. Alternative 3 is the next most

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expensive remedy ($1,545,000) followed by Alternative 3B ($1,620,000). While these
alternatives would address ARARs and TBCS for Site 2, they would not provide the additional
environmental benefit of removing the trenched wastes that include batteries known to contain
lead, zinc, and manganese and other wastes from the western and southern trench disposal areas.

The capital, operating, and 30-year net present-worth costs of the alternatives are presented in
the following table including 30-year net present-worth cost.

Alternative Capital($) Operating($/yr) Present-Worth ($)
1 $0 $0 $0
2 $396,000 $26,000 $876,000
2A $818,000 $26,000 $1,298,000
3 $1,065,000 $26,000 $1,545,000
3A $1,550,000 $26,000 $2,030,000
3B $1,140,000 $26,000 $1,620,000
4 $1,510,000 $26,000 $1,990,000

Note: Baseline (numbered) alternatives assume no action is performed on
the western debris pile. 'A' alternatives assume offsite disposal of western
debris pile materials. 'B' alternatives assume western debris pile materials
are consolidated beneath the cap for the alternative indicated.

Note that the operating cost in each alternative is attributable to monitoring of groundwater,
sediments and surface water.

2.7.3 Modifying Criteria

State Acceptance

The Virginia Department of Environmental Quality on behalf of the Commonwealth of Virginia,
has reviewed the information available for this site and concurs with this ROD and the selected
remedy identified below.

Community Acceptance

Community Acceptance summarizes the public's general response to the afternatives, described
in the Proposed Plan and the Feasibility Study. No written comments were received during the
thirty-day comment period, which began on July 30 and ended on August 29, 1997.
There were no comments or guestions received at the Proposed Plan Public Meeting held
August 6, 1997, Background on Community involvement at NSWDL is included in the
Responsiveness Summary, Section 3.0 of the ROD.

2.8 THE SELECTED REMEDY

The selected remedy for Site 2 is Alternative 4 which involves the removal of soils exceeding
remediation goals; removal of the western and southern trenches and debris piles, backfilling
with clean fill; consolidating all removed wastes onsite, recycling recyclable materials from debris
piles offsite; capping the fenced area and consolidated waste and soils; and providing
institutional controls to limit the site to future industrial use and to exclude shallow groundwater
use. Surface water and groundwater shall continue to be monitored.

The major components of the selected remedy are:

The Navy shall remove soils which are above the RAOs in selected areas on the site. These
areas are identied on Figure 2-4 as areas with soil above PRGs. These soils shall be
consolidated underneath the fenced area landfill cap.

The Navy shall excavate the wastes from the southern and western trenches and backfill with

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clean fill. The Navy shall consolidate the excavated wastes underneath the fenced area landfill cap.

The Navy shall construct a multi-layer cap over the fenced area and the area over the excavated
trenches. The cap shall be consistent with RCRA Subtitle C requirements and the Virginia
Hazardous Waste Management Regulations (VFHWMR). It shall consist of a minimum of 24
inches of topsoil and vegetative cover underlain by a filter layer and 12 inches of drainage
(minimum 10 -2 cm/sec), a minimum 20 mil geomembrane, and 24 inches of compacted soil or
clay or equivalent design achieving a maximum hydraulic conductivity of 10 -7 cm/sec. The cap
shall include a passive gas collection system and a perimeter drainage system.

The Navy shall develop and implement an operating and maintenance plan for the landfill. The
Navy shall also implement all post-closure requirements for the landfill, including the certification
of closure to the Regional Administrator within 60 days of completion of the cap.

The Navy shall institute the following institutional controls within 60 days of completion of the
cap: a real property description notation, Base Master Plan notations, and limited site access.
Fendng shall be erected around the landfill area and signs shall be posted which state that
hazardous wastes are present. The Base Master Plan shall note the area as one in which
construction changes can not occur, residential development can not occur, shallow groundwater
can not be used, and site access shall be limited. A notation shall be filed in the real property
file maintained at EFA Chas for this sde indicating the extent of the area and the fact that
hazardous wastes are present. Institutional controls shall also include the following: Within 60
days of closure (capping), the Navy shall produce a survey plat indicating the location and
dimensions of landfill calls or other hazardous waste disposal units with respect to permanently
surveyed benchmarks. This plat shall be prepared and certified by a professional land surveyor.
The plat shall contain a note, prominently displayed, which states the owner's obligation to
restrict disturbance of the hazardous waste disposal unit, post-closure use shall prohibit
residential use, shall prohibit access or use of groundwater underlying the property for any
purpose except monitoring, and shall never be allowed to disturb the integrity of the final cover,
liners, or any other components of the containment system, or the function of the facility's
monitoring systems. No later than 60 days after closure, the Navy shall submit to the county
board of supervisors a record of the type, location, and quantity of hazardous wastes disposed of
within each cell or other disposal unit of the facility.

As soon as practicable, the owner shall record, in accordance with state and local law, a notation
an the deed to the property - or on some other instrument which is normally examined during title
search - that will in perpetuity notify any potential purchaser of the property that the land has
been used to manage hazardous wages, that its use is restricted as described above, and that a
survey plat and a record of the type, location, and quantity of hazardous wastes disposed of
have been filed with the local government. If and when the property is transferred out of the
federal government, the deed shall contain the survey plat, the notation that the property was
previously used to manage hazardous wastes and that its future use is restricted, and other deed
restrictions as-appropriate.

The Navy shall institute groundwater monitoring at the perimeter of the landfill cap and shall
continue monitoring for 30 years, the post-closure time period as required by RCRA and VHWMR.

The Navy shall monitor the drainage system surrounding the cap, surface waters, and sediments
in Gambo Creek adjacent to Site 2. The frequency of analysis and the length of time for
monitoring shall be developed in the Operation and Management Plan.

Based on available information and the current understanding of site conditions, Alternative 4
appears to provide the best balance with respect to the nine NCP evaluation criteria. In addition,
the selected alternative is anticipated to meet the following statutory requirements:

• Protection of human health and the environment.
• Compliance with ARARs.
• Cost-effectiveness.

The selected alternative provides for the removal and containment of surface soil, trench, and
debris pile wastes at Site 2, and prevents direct contact with ordnance-contaminated materials
inside the fenced area of the site. The selected alternative will provide for the long-term
reduction of leachate generation and reduce potential future contamination of the groundwater

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beneath the disposal area. This alternative addresses Virginia DEC and EPA solid and
hazardous waste regulations by using a RCRA Subtitle C cap design. As discussed previously in
this ROD, a separate study will be prepared which addresses possible surface water and
sediment contamination in Gambo Creek.

2.8.1 Performance Standards

Soils and Trench-Contents Removal

All soil above RAOs in the areas identified on Figure 2-4 shall be removed and consolidated
underneath the fenced area landfill. The southern and western trenches (Figure 2-4) shall be
excavated and consolidated underneath the fenced area landfill. The southern and western
debns piles (Figure 2-4) shall be removed, recyclable materials recycled, and the remaining
material consolidated underneath the fenced area landfill cap.

Landfill Cap

The landfill cap shall be designed, constructed, operated, and maintained to meet the
performance reguirements of RCRA Subtitle C, regulations specified in 40 C.F.R. °°265.19,
265.111 and 265.310 and VHWMR.

The cap shall also be designed to meet the reguirements of the following EPA technical
guidance documents: "Final Covers on Hazardous Waste Landfills and Surface Impoundments"
(EPA/530-SW-89-047, July 1989); and "Construction Quality Management for Remedial Action
and Remedial Design Waste Containment Systems" (EPA/540/R-92/073, October 1992).

The cap design shall minimize infiltration, and control surface water run onlrunoff. The landfill
cap shall be constructed, at a minimum to the following performance standards:

Compacted soil or clay Layer - 24 inches of material or eguivalent design achieving a
maximum hydraulic conductivity of 1x10 -7 cm/sec.

Geomembrane Layer - Minimum 20 mil thick low permeability membrane.

Drainage Layer - Composed of a minimum 12 inches of sand or soil having a minimum
hydraulic conductivity of 1x10 -2 cm/sec.

Soil Cover Layer - Minimum 24 inches in thickness.

Surface water drainage controls shall be constructed to prevent erosion of the cap. As
determined by the final Site 2 Cap Design, drainage channels shall be installed in certain areas
on the top and perimeter of the landfill cap to channel runoff away from the landfill.

The cap shall be capable of managing residuals and achieving all RAOs within the boundaries of
Site 2, and shall meet all ARARs and TBCs for the site. Managing residuals shall include the
monitoring and collection and treatment of any leachate and generated gases, as reguired.

RCRA Groundwater Monitoring Wells

A groundwater mondoring network shall be implemented in accordance with RCRA and
VHWMR. It shall be installed at the perimeter of the unit to evaluate any future contaminant
transport. The location and number of monitoring wells, the freguency of analyses, and the types
of analyses shall be determined in the site design and operation and management documents.
These documents must be approved by the EPA and the Commonwealth of Virginia.
Groundwater monitoring shall continue for 30 years, the post-closure time period as reguired by
RCRA. The wells shall be installed according to RCRA and Commonwealth of Virginia
construction reguirements.

Surface Water, Sediment, and Drainage System Monitoring

A surface water, sediment and drainage system sampling and monitoring plan shall be
developed as part of the Operation and Management (0 & M) Plan. The location and number of
sampling locations, the freguency of analyses, the types of analyses, and the duration of

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monitoring shall be determined in the 0 & M Plan. This plan must be approved by the EPA and
the Commonwealth of Virginia.

Institutional Controls

Fencing shall be installed and signs shall be posted indicating hazardous materials are present.
The Base Master Plan shall be updated with notations indicating Site 2 is an area in which
construction changes can not occur, residential development can not occur, shallow groundwater
can not be used, and site access shall be limited. A notation shall be filed in the real property
file maintained by EFA Ches for this site indicating the extent of the area and the fact that
hazardous wastes are present.

Within 60 days of closure (capping), the Navy shall produce a survey plat indicating the location
and dimensions of landfill cells or other hazardous waste disposal units with respect to
permanently surveyed benchmarks. This plat shall be prepared and certified by a professional
land surveyor. The plat shall contain a note, prominently displayed, which states the owners
obligation to restrict disturbance of the hazardous waste disposal unit; post-closure use shall
prohibit residential use, shall prohibit access or use of groundwater underlying the property for
any purpose except monitoring, and shall never be allowed to disturb the integrity of the final
cover, liners, or any other components of the containment system, or the function of the facility's
monitoring systems. No later than 60 days after closure, the Navy shall submit to the county
board of supervisors a record of the type, location, and guantity of hazardous wastes disposed of
within each cell or other disposal unit of the facility.

If and when the the property is transferred out of the federal government, the deed shall contain
the survey plat, the notation that the property was previously used to manage hazardous wastes
and other deed restrictions as appropriate.

In the yearly 0 & M Report, the Navy shall certify that the institutional controls as outlined above
are still in-place and effective. The Navy shall notify USEPA and VADEQ 60 days before
changing any of the use restrictions in the Base Master Plan related to Site 2.

2.9 STATUTORY DETERMINATIONS

Remedial actions must meet the statutory reguirements of Section 121 of CERCLA as discussed
below. Remedial actions undertaken at NPL sites must achieve adeguate protection of human
health and the environment, comply with applicable or relevant and appropriate reguirements of
both Federal and State laws and regulations, be cost effective, and utilize, to the maximum
extent practicable, permanent solutions and alternative treatment or resource recovery
technologies. Also, remedial alternatives that reduce the volume, toxicity, and/or mobility of
hazardous waste as the principal element are preferred. The following discussion summarizes
the statutory reguirements that are met by the selected remedy.

2.9.1 Protection of Human Health and tho Environment

The selected remedy will protect human health and the environment. The installation of a RCRA
Subtitle C cap consistent with the Commonwealth of Virginia and EPA solid and hazardous
waste regulations will eliminate direct contact wfth ordnance-contaminated materials, eliminate
direct contact, ingestion, and inhalation threats from contaminated soils, and will reduce the
leaching of contaminants to groundwater by controlling precipitation entering the landfill and
minimizing leachate generation. There will be limited short term risks as with any construction
activity at the site. However, the short-term risk should be minimal because fenced area wastes
will not be removed during construction activities. Also, the permanent cap will effectively
stabilize existing conditions at the landfill.

2.9.2 Compliance with ARARs

The selected remedy will be constructed to meet all applicable or relevant and appropriate
reguirements (ARARs) whether chemical-, action-, or location-specific. No waivers of any
ARARs are reguested. ARARs that have been identified for Site 2 are presented in Appendix C.

Location- and action-specific ARARS and TBCs that will be addressed by the selected remedy
include Federal and Commonwealth of Virginia hazardous waste regulations related to the

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installation of the cap (40 CFR 260-279, 9 VAC 20-80), landfill closure requirements and
performance standards (40 CFR 264, 9 VAC 20-60-870), regulations and guidance regarding
ordnance wastes (40 CFR 260, DoD 6055.9-STD), endangered species protection (50 CFR Part
402) and wetlands protection (10 CFR 1021) . In addition, related Commonwealth of Virginia
regulations pertaining to storm water management (9 VAC 25-180), sediment and erosion control
(4 VAC 50-30), and air emissions (VAC 5-50) during contruction will be addressed.

The low permeabilfty RCRA Subtitle C cap will be designed to meet the performance standards in section 2.8.1.

The cap will achieve all RAOs within the boundaries of Site 2, and will meet all ARARs and
TCBs for the site.

Regular inspections of the cap shall be conducted to ensure that its integrity is maintained and
that it is functioning as designed. The O&M plan will include procedures to repair and/or replace
components of the cap as necessary, to maintain its grade and vegetative cover in order to
control sedimentation and erosion. The operation and maintenance program shall state that a
yearly evaluation of the vegetative cover will be made by a qualified individual.

New monitoring wells will be installed in accordance with Commonwealth of Virginia
requirements. The specific analytical methods, procedures and sampling frequency will be
specified in the O&M plan. Substantive permit and licensing requirements shall be followed.
Land-use and access restrictions will limd the use and development of the property, These
restrictions will ensure the long-term effectiveness and integrity of the cap.

2.9.3 Cost-Effectiveness

The selected remedy is cost-effective because it provides overall effectiveness proportional to
the cost. Although more costly than the alternative that removes soils exceeding remediation
goals (Alternative 2), the alternative provides for the removal and containment of hazardous
wastes, and the recovery of recycleable metals and therefore provides greater long-term
protection of human heafth and/or the environment than other alternatives, and meets all
required ARARs.

2.9.4 Utilization of Permanent Solutions and Alternative Treatment
Technologies or Resource Recovery Technologies to the Maximum Extent Practicable ("MEP")

Capping is a permanent solution and is a common remedy for land filled wastes of high volume
and low contaminant concentration. Containment in the form of capping is typical and
appropriate for a site of this type. In addition, this alternative provides for additional
protectiveness provided by a RCRA Subtitle C cap and the recovery of recycleable metals to the
maximum extent practicable, and therefore addresses this goal.

2.9.5 Preference for Treatment as a Principal Element

The selected remedy does not utilize permanent treatment technologies for this site due to cost
and other considerations. Although this action does not fully address the statutory mandate for
treatment, this action provides for a permanent remedy and thus partially satisfies this mandate.

3.0 RESPONSIVENESS SUMMARY

The selected remedy for Site 2 is a composite cap comprised of a geosynthetic clay liner (GCL)
and a minimum 20 mil flexible membrane cap (FMC). No written comments, concerns, or
questions were received by the Navy, EPA, or the Commonwealth of Virginia during the public
comment period from July 30, 1997 to August 29, 1997. A public meeting was held on August 6,
1997 to present the Proposed Plan for Site 2 and to answer any questions on the Proposed Plan
and on the documents in the information repositories. No formal questions were asked during
the meeting. Based on the limited comments, the Public appears to support the selected remedy.

A copy of the certified transcript of the formal Public Meeting is attached as Appendix B.

Both the EPA and the Virginia Department of Environmental Quality, representing the
Commonwealth of Virginia, concur that the selected remedy is protective of human health and

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the environment.

3.1           BACKGROUND ON COMMUNITY INVOLVEMENT

The Navy and NSWCDL has had a comprehensive public involvement program for several
years.  Starting in 1993, a Technical Review Committee (TRC) would meet on average twice a
year to discuss issues related to investigative activities at NSWCDL.  The TRC was comprised of
mostly governmental personnel, however a few private citizens attended the meetings.

In early 1996, the Navy converted the TRC into a Restoration Advisory Broad (RAB)  and 8-10
community representatives joined.  The RAB is co-chaired by a community member and has
held meetings approximately every four to six months since.  The Feasibility Study for Site 2 and
the Proposed Plan were both discussed at the RAS meetings and a Site 2 tour was undertaken
during a special RAS meeting.

Community relations activities for the final selected remedy include:

The documents concerning the investigation and analysis at Site 2, as well as a copy of the
Proposed Plan were placed in the information repository at the NSWCDL Library and King
George Public Library.

Copies of the documents, including the Proposed Plan in were sent to the members of the RAB.

Newspaper announcements on the availability of the documents and the public comment
period/meeting date was placed in the Freelance Star Newspaper on July 29, 1997.

The Navy established a 30-day public comment period starting July 30, 1997 and ending August
29, 1997 to present the Proposed Plan.  No written comments were received during the 30-day
public comment period.

A Public Meeting was held August 6, 1997 to answer any guestions concerning the Site 2
Proposed Plan.  Approximately 20 people, including Federal, State and local government
representatives attended the meeting.

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                                      APPENDIX A

                             VIRGINIA CONCURRENCE LETTER

                                            COMMONWEALTH of VIRGINIA
       George Allen                  DEPARTMENT OF ENVIRONMENTAL QUALITY                 Thomas L. Hopkins
          Governor        Street  address:   629  East  Main Street Richmond,  Virginia 23219         Director
                           Mailing address:   P.O.  Box 10009,  Richmond,  Virginia 23240
    Becky Norton Dunlop                 Fax  (804)  698-4500  TDD  (804)  698-4021                  (804)  698-4000
Secretary of Natural Resources          http://www.deg.state.va.us                           1-800-592-5482

                                               September 25, 1997

CAPT. Vaughn E. Mahaffey, USN
Commanding Officer
Naval Surface Warfare Center
Dahlgren, Virginia

Re:    Record of Decision for Site 2 (Fenced Ordnance Burial Area),  Naval Surface Warfare Center,
      Dahlgren, VA

Dear Captain Mahaffey:

The Virginia Department of Environmental Quality has reviewed the final Record of Decision for
Site 2, the Fenced Ordnance Burial Area at the Naval Surface Warfare Center, Dahlgren, VA.  On
the behalf of the Commonwealth of Virginia, the Virginia Department of Environmental Quality
hereby concurs with this Record of Decision and the selected remedy for Site 2, Alternative 4 as
specified therein.  This involves the removal of soils exceeding remediation goals; removal of the
western and southern trenches and debris piles; backfilling with clean fill; consolidating all removed
wastes onsite, recycling recyclable materials from debris piles offsite; capping the fenced area and
consolidated waste and soils; and providing institutional controls to limit the site to future industrial
use and to exclude shallow groundwater use.  Surface water and groundwater shall continue to be monitored.

Please let me know if there are any guestions,  or if I can be of additional assistance.

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                                     APPENDIX B

                               RESPONSIVENESS SUMMARY

                              NAVAL SEA SYSTEMS COMMAND

                             NAVAL SURFACE WARFARE CENTER
                                  DAHLGREN DIVISION

                                    PUBLIC MEETING

                         WEDNESDAY, AUGUST 6, 1997, 7:00 P.M.
                      KING GEORGE COUNTY ADMINISTRATION BUILDING
                                 KING GEORGE, VIRGINIA

                              PROPOSED REMEDIAL ACTION PLAN
                           Site 2, Fenced Ordnance Burial Area
USEPA Region III
Hazardous Waste Management Division
Federal Facilities Section
Mr. Bruce Beach
841 Chestnut Building, Philadelphia, Pennsylvania 19107

Virginia Department of Environmental Quality
Mr. David Gillispie
629 East Main Street, Richmond, Virginia 23225

Public Affairs Office
Commander, Naval Surface Warfare Center
Ms. Jennifer Wilkins
17320 Dahlgren Road, Dahlgren, Virginia 22448
                                           Reported by: Paula J. Evans

                    FRANCES K. HALEY & ASSOCIATES, Court Reporters
               10500 Wakeman Drive, Suite 300, Fredericksburg, VA 22407
                     PHONE:   (540)898-1527    FAX:   (540)898-6154
August 6, 1997:

          There were no formal guestions on the floor at this Meeting.

                    FRANCES K. HALEY & ASSOCIATES, Court Reporters
               10500 Wakeman Drive, Suite 300, Fredericksburg, VA 22407
                     PHONE:   (540)898-1527    FAX:   (540)898-6154

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                            CERTIFICATE OF COURT REPORTER

               I, Paula J. Evans, hereby certify that I was the

     Court Reporter at the Public Meeting held at King George

     County Administration Building, King George, Virginia, on

     August 6, 1997, at the time of the meeting herein.

               I further certify that the foregoing transcript is a

     true and accurate record of the proceeding herein.

               Given under my hand this 19th day of August, 1997.



                    FRANCES K. HALEY & ASSOCIATES, Court Reporters
               10500 Wakeman Drive, Suite 300, Fredericksburg, VA 22407
                     PHONE:   (540)898-1527    FAX:   (540)898-6154

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                                                       APPENDIX C
                                      Applicable or Relevant and Appropriate Requirements
                                              Site 2 Fenced Ordnance Burial Area
                                                  NSWCDL, Dahlgren, Virginia
                            Regulation
                     Classification
    Requirement Synopsis
          Alternatives
Applicability to Remedial ARAR or TBC
1. LOCATION
   SPECIFIC
Endangered
Species Act of
1978

Virginia
Endangered
Species
Regulations
Virginia Board of
Game and Inland
Fisheries:  Virginia
Endangered Plant
and Insect Species
Regulations
                         16 USC 1531-1544
                         50 CFR Pan 402
 VR 325-01-1
4 VAC 15-20-130
 Code of Virginia
   Sections  29.1-100
   and 29.1-563
VR 115-04-01
  2 VAC 5-320-10
                       Applicable
                                             Applicable
Act requires federal agencies to ensure that
any action authorized by an agency is not
likely to jeopardize the continued existence
of any endangered or threatened species or
adversely affect its critical habitat.  Similar
Virginia requirements for submittal and
review of environmental assessments.
The Department of Game and Inland
Fisheries  (DGIF)  determines if rare,
threatened or endangered animal species or
their habitats are threatened by remediation
of the site.  Certain species of fish and
wildlife are afforded special preservation
and protection measures.  The Department
of Conservation and Recreation (OCR)
determines if any ecologically significant
areas are threatened by the remediation of
the site.
       Potentially  affected
       endangered species have not
       been  identified  at NSWC
       Dahlgren.  The remedial action
       will  be  implemented so
       resources are not adversely
       affected, should such resources
       be  identified in the future.
       Potentially  affected
       endangered species have been
       identified at NSWC Dahlgren.
       The  remedial action will be
       implemented  so  resources are
       not  adversely affected should
       any  be  identified in  the future.

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The Archaeological
and Historical
Preservation Act of
1974

Virginia Historic
Resources Law
                                                          APPENDIX C
                                      Applicable or Relevant and Appropriate Reguirements
                                              Site 2 Fenced Ordnance Burial Area
                                                  NSWCDL, Dahlgren, Virginia
16 U.S.C
           469
Applicable
VR 10.1-2200-2214
Reguires actions to avoid potential loss or
destruction of significant scientific,
historical, or archaeological data
Site is not known to be within a
historically significant area.  If
future resources are identified
actions will be taken to ensure
compliance
Migratory Bird
Area
16 USC Section 703
 Applicable
Protects almost all species of native birds in
the U.S. from unregulated "take" which can
include poisoning at hazardous waste sites.
Remedy will be implemented to
ensure that hazardous wastes
have no impacts to native birds.
Chesapeake bay
Preservation Act
Resource
Conservation and
Recovery Act

Virginia Hazardous
Waste Management
Regulations
   VR 173-02-01
   9 VAC 10-20-10
 Applicable
  40 C.F.R. 264.18
   (b)

 VR 672-20-10
9 VAC 20-80-10
Applicable
Reguires certain locally designated tidal and
 non-tidal wetlands and other sensitive areas
 be subject to limitations regarding land-
 disturbing activities,  removal of vegetation,
 use of impervious cover,  erosion and
 sediment control, and stormwater
 management.

  Applies to treatment,  storage, or disposal of
 hazardous waste.
Remedy implementation will
reguire construction activities
Actions will address the
regulatory reguirements
Remedy implementation may
 produce incidental hazardous
wastes which will be managed
consistent with federal and
Virginia reguirements

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Virginia Water
Control Board
Regulations
Executive Order
11988, Protection
of Floodplains
Executive Order
11990, Protection
of Wetlands
Virginia Wetlands
Regulations
Virginia Water
Permit Regulations
                                                          APPENDIX C
                                      Applicable or Relevant and Appropriate Reguirements
                                              Site 2 Fenced Ordnance Burial Area
                                                  NSWCDL, Dahlgren, Virginia
  VR 680-21-04
  9 VAC 25-260-10
  40 C.F.R.  6,
  Appendix A;
  excluding  Sections
6(a)(2), 6(a)(4),
6(a)(6), 40 C.F.R.
6.302
  40 C.F.R.  6,
  Appendix A

Clean Water Act of
1972  (CWA)
Section 404

VR 450-01-0051
  4 VAC 20-390-10
VR680-15-02
  9 VAC 25-210-10
Relevant and
 Appropriate
Applicable
Applicable
Relevant and
 appropriate
Facility or activity design must adeguately
address the issues arising from locating in
wetlands, delineated (wellhead protection
areas determined vulnerable.)
Facilities or activities located within the
floodplain must comply with this order.
Action to minimize the destruction, loss, or
degradation of wetlands.
Any activity to take place in, or impact on,
a tidal wetland must meet the provisions of
Virginia Wetlands Act and regulations as
applicable

Procedures and reguirements in connection
with 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 waters
  Remedy implementation is not
  expected to involve wetland or
  wellhead protection areas.  If
  identified, actions will address
  the regulation.

  Site is adjacent to Gambo
  Creek and is therefore partially
  in the 100 year floodplain.
  Remedy will not be installed in
  the floodplain and will be
  constructed to avoid impacts to
  floodplain resources.

  Portions of the site adjacent to
  Gambo Creek are characterized
  as wetlands.  Remedy
  implementation will be
  completed to avoid wetland
  impacts.
Construction of landfill could
potentially involve discharge of
contaminants to Gambo Creek
Any potential discharges will
meet reguirements

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                                                          APPENDIX C
                                      Applicable or Relevant and Appropriate Requirements
                                              Site 2 Fenced Ordnance Burial Area
                                                  NSWCDL, Dahlgren, Virginia
II.  ACTION
     SPECIFIC
Capping /Closure
and Post Closure
   40  CFR  258.60-61  Applicable
Military Munitions
Rules
(40 CFR 260-266
and 270)
 To Be
Considered
 Requirements for final cover systems to
 minimize infiltration and erosion.
Requirements for 30 year post closure care
including maintaining integrity and
effectiveness of final cover.  Maintenance of
groundwater monitoring and landfill gas
monitoring systems.

 Recently promulgated regulations in
 response to Section 107 of the  Federal
 Facilities Compliance Act of 1992,
 identifying when conventional and chemical
 military munitions become hazardous
 waste.
                                                                          Installation of RCRA Subtitle C
                                                                          cap requires adherence to these
                                                                          regulations at Site 2.
Ordnance-related wastes buried
in the fenced area of Site 2 will
be managed in compliance with
the rules.
DoD Guidance on
Property
Contaminated with
Ammunition,
Explosives or
Chemical Agents
  DoD  6055.9-STD
                    To Be
                  Considered
                    Dod  guidance  document  stipulating policy
                  and procedure to provide protection of
                   personnel resulting from DoD ammunition,
                   explosives or chemical agent contamination.
                   Includes property currently or formerly
                   owned, leased or used by DoD, and calls
                   for identification  and  control at active
                   installations, and  provides  guidance  for
                   potential  land disposal.
                                                        Capping of the fenced area will
                                                        be completed to be consistent
                                                        with DoD policy and
                                                        procedures to address safety

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                                                          APPENDIX C
                                      Applicable or Relevant and Appropriate Requirements
                                              Site 2 Fenced Ordnance Burial Area
                                                  NSWCDL, Dahlgren, Virginia
Erosion and
Sediment Control
Resource
Conservation and
Recovery Act
  VR 625-02-00
   4 VAC 50-30-10
                         40 C.F.R.  265.19
Applicable
Virginia Hazardous     9 VAC 20-60-580 B
Waste Management
Regulations
(VHWMR)
                             Applicable
                             Applicable
Resource
Conservation and
Recovery Act
(RCRA)
40 C.F.R.  265.111
Erosion and sediment control plans are to
be prepared for land-disturbing activities.
                   Construction Quality Assurance  Program.
                   For a closing facility,  owner must  minimize
                   need for further maintenance; control,
                   minimize,  or eliminate  post-closure escape
                   of hazardous waste,  hazardous constituents,
                   leachate,  contaminated  run-off,  or
                   hazardous  waste  decomposition products  to
                   the ground or surface waters  or  to  the
                   atmosphere;  and  comply  with other closure
                   requirements.
Construction activities will
disturb the land in the vicinity
of the site.  Activities will
address Virginia erosion and
sediment control requirements.

Installation of RCRA Subtitle C
cap will address construction
quality requirements under
RCRA.

VHWMR/RCRA requirements
will be met with the installation
of the cap at Site 2.   Designs
for capping, and construction of
the  containment unit and
appurtenances will conform
with engineening practice and
RCRA requirements.

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                                                         APPENDIX C
                                      Applicable or Relevant and Appropriate Requirements
                                              Site 2 Fenced Ordnance Burial Area
                                                  NSWCDL, Dahlgren, Virginia
Virginia Hazardous
Waste Management
Regulations
(VHWMR)
Resource
Conservation and
Recovery Act
(RCRA)

Virginia Hazardous
Waste Management
Regulations
(VHWMR)
           9 VAC 20-60-580 E
                         40 C.F.R. 265.114
Applicable
           9 VAC 20-60-580 F
                         40 C.F.R. 265.115
                                    Relevant and
                                   Appropriate
Resource
Conservation
Recovery Act
(RCRA)
and
During final closure, all contaminated
equipment, structures, and soil must be
properly disposed of, or decontaminated.
                   Within 60  days  of completion of closure,
                   the owner  or operator must submit to the
                   Regional Administrator,  by registered mail,
                   a certification that the unit has been closed
                   in accordance with approved plans and
                   specifications.
VHWMR/RCRA requirements
will be met with the installation
of the cap at Site 2.   Work
Plans addressing these
requirements will be submitted
for review and approval by the

Navy, EPA and VDEQ.
                                                       VHWMR/RCRA requirements
                                                       will be met with the installation
                                                       of the cap at Site 2.
                                                       Documentation of completion
                                                       of construction activities at Site
                                                       2 will be submitted within
                                                       required time frames.

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                                                          APPENDIX C
                                      Applicable or Relevant and Appropriate Requirements
                                              Site 2 Fenced Ordnance Burial Area
                                                  NSWCDL, Dahlgren, Virginia
Virginia Hazardous
Waste Management
Regulations
(VHWMR)
Resource
Conservation and
Recovery Act
(RCRA)

Virginia Hazardous
Waste Management
Regulations
(VHWMR)
Resource
Conservation and
Recovery Act
(RCRA)
9 VAC 20-60-580
       G
Relevant and
Appropriate
                          40 C.F.R.  265.116
   9 VAC 20-60-580
       H
Relevant and
Appropriate
                          40 C.F.R.  265.117
No later than the submission of the
certification of closure, an owner or
operator must submit to the local zoning
authority and to the Regional
Administrator, a survey plat indicating the
location and dimensions of the landfill with
respect to permanently surveyed
benchmarks.
Post-closure care for each hazardous waste
management unit must begin after
completion of closure and continue for 30
years after that date.  It must consist of
monitoring and reporting under
requirements RCRA Subpart N and
maintenance and monitoring of waste.
containment systems.
VHWMR/RCRA requirements
will be met with the installation
of the cap at Site 2.  Surveys
providing vertical and
horizontal control will be
prepared and submitted to
appropriate authorities upon
completion.
VHWMR/RCRA requirements
will be met with the installation
of the cap at Site 2.
Monitoring requirements will
be negotiated between the
Navy, VDEQ, and EPA,
consistent with post-closure
requirements  under RCRA.

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                                                          APPENDIX C
                                      Applicable or Relevant and Appropriate Requirements
                                              Site 2 Fenced Ordnance Burial Area
                                                  NSWCDL, Dahlgren, Virginia
Virginia Hazardous
Waste Management
Regulations
(VHWMR)
Resource
Conservation and
Recovery Act
(RCRA)
9 VAC 20-60-580 I   Applicable
                         40 C.F.R. 265.118
The owner or operator must develop a
written post-closure plan.  The post-closure
plan must identify activities to be carried on
after closure and the frequency of these
activities.  The activities include a
description of the planned monitoring
activities and frequencies to be performed, a
description of the planned maintenance
activities and frequencies to be performed
to ensure the integrity of the cap and final
cover and the function of the monitoring
equipment.  The post-closure plan must
also include the name, address, and phone
number of the person to contact during the
post-closure care period.
VHWMR/RCRA requirements
will be met with the installation
of the cap at Site 2.
Appropriate post-closure plans
will be developed and
implemented consistent with
RCRA requirements.

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                                                          APPENDIX C
                                      Applicable or Relevant and Appropriate Requirements
                                              Site 2 Fenced Ordnance Burial Area
                                                  NSWCDL, Dahlgren, Virginia
Virginia Hazardous
Waste Management
Regulations
(VHWMR)
Resource
Conservation and
Recovery Act
(RCRA)
9 VAC 20-60-580 J
                   Relevant and
                    Appropriate
                         40 C.F.R. 265.119
Virginia Hazardous
Waste Management
Regulations
(VHWMR)
Resource
Conservation and
Recovery Act
(RCRA)
   9 VAC 20-60-580 K   Applicable
                         40 C.F.R. 265.120
The owner or operator must, within 60 days
after certification of closure of each
hazardous waste disposal unit, submit to the
local zoning authority and to the Regional
Administrator a record of the type, location,
and quantity of hazardous waste disposed
of within the disposal unit.  The owner or
operator must record a notation on the
deed, or other legal instrument to the
facility property that will perpetuity notify
any potential purchaser of the property that
the land has been used to manage
hazardous waste, its use is restricted under
40 C.F.R. Subpart G regulations and that a
survey plat is included.  The owner or
operator must submit a certification that he
has recorded the notation on the deed.

The owner or operator, within 60 days after
completion of the post-closure care period,
must submit to the Regional Administrator,
by registered mail, a certification that the
post-closure care period was performed in
accordance with the specifications in the
approved post-closure plan.
VHWMR/RCRA requirements
will be met with the installation
of the cap at Site 2.
Appropriate deed notations will
be prepared by the Navy to
address notification
requirements under RCRA
regarding the presence of
wastes at Site 2.
VHWMR/RCRA requirements
will be met with the installation
of the cap at Site 2.   The
required notifications will be
completed to address RCRA
requirements at Site 2.

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                                                         APPENDIX C
                                      Applicable or Relevant and Appropriate Requirements
                                              Site 2 Fenced Ordnance Burial Area
                                                  NSWCDL, Dahlgren, Virginia
Virginia Hazardous
Waste Management
Regulations
(VHWMR)
Resource
Conservation and
Recovery Act
(RCRA)

Solid Waste
Management Act
9 VAC 20-60-650
Applicable
Virginia
Regulations
Governing
Transportation of
Hazardous
Materials
(VRGTHM)
                         40 C.F.R. 265.310
 VR  672-20-10
   9 VAC  20-80-10
Applicable
 VR  672-30-01
 9 VAC  20-110-10
Applicable
Final cover to provide long-term minimiza-
tion of infiltration.  Restrict post-closure
use of property to prevent damage to the
cover.  Prevent run-on and run-off from
damaging the cap.  30-year post-closure
care to ensure site is maintained and
monitored.
Permanent Closure Criteria governing:
Access Restriction, Closure and Post
Closure Care, Gas Management,  Drainage
Layer, Final Cover, Run-on Run-off
controls, Site Monitoring, and compliance
with other permanent closure requirements.
The VRGTHM designates the manner and
method by which hazardous materials are
loaded,  packed, identified, marked,
placarded, stored and transported.
 VHWMR/RCRA requirements
 will  be  met with the  installation
 of the cap at Site  2.  Access  to
 the site will be restricted by
 fencing,  and monitoring  and
 inspection activities  will  be
 conducted.
 Virginia Solid Waste
 Management  requirements
 need to be  addressed  with the
installation of the cap at Site 2.
 Overlapping with RCRA, the
 additional  requirements  under
 solid waste rules will be
 addressed.

 Transportation of a hazardous
 waste must  be conducted  in
 compliance  with VRGTHM.
AIR

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Gas Collection and
Vents
Gas Collection and
Vents
Gas Collection and
Vents
Gas Collection and
Vents
Gas Collection and
Vents
APPENDIX C
Applicable or Relevant and Appropriate Requirements
Site 2 Fenced Ordnance Burial Area
NSWCDL, Dahlgren, Virginia
CAA Section 101
and 40 C.F.R. 52
40 C.F.R. 52
Relevant and
Appropriate
Relevant and
Appropriate
40 C.F.R. 60
Subpart WWW and
CC
To Be
Considered
CAA Section
112(D)
CAA Section 118
Relevant and
Appropriate
Relevant and
Appropriate
File an Air Pollution Emission Notice
(APEN) with the State to include
estimation of emission rates for each
pollutant expected. Design system to
provide an odor-free operation.

Predict total emission of volatile organic
compounds (VOCs) to demonstrate
emissions do not exceed 450 Ib/hr, 3,00
Ib/day, 10 gal/day or allowable emission
levels from similar sources using
Reasonably Available Control Technology
(RACT).

New Source Performance Standard (NSPS)
for municipal landfills: Landfill Emission
Rule, deals with non-methane organic
compounds.
Emission Standards for new stationary
sources.
Control of pollution from Federal Facilities.
Design of capped area
anticipated to include venting
to ensure cap functions as
intended.
Design of capped area to
demonstrate that decomposition
gases address regulatory
requirements.
NSPS requirements include
calculations for gas emission
rates, limitations on non-
methane emissions, monitoring
and recordkeeping. Rules are a
TBC since Site 2 is not to
receive MSW, and emissions of
non-methane gases should be
insignificant.

NSPS for venting.
Confirmation that standards not
exceeded will be addressed.

NSWCDL is a Federal Facility
to address CAA requirements.

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                                                          APPENDIX C
                                      Applicable or Relevant and Appropriate Requirements
                                              Site 2 Fenced Ordnance Burial Area
                                                  NSWCDL, Dahlgren, Virginia
Virginia Ambient
Air Quality
Standards
       VR 120-03-01
      9 VAC 5-30-10
Relevant and
Appropriate
WATER

Criteria for
Classification of
Solid Waste
Disposal Facilities
and Practices
Criteria for
Classification of
Solid Wage
Disposal Facilities
and Practices
49 C.F.R.  257.3-
       3(a)
Applicable
49 C.F.R.  257.3-
       3(a)
Applicable
Stipulates requirements for compliance with
emissions of toxic pollutants in attainment
and non-attainment areas:  permitting
procedures and monitoring requirements for
processes emitting pollutants:  anu emission
from the disturbance of soil must meet
Virginia air emission standards for toxic
pollutants particulates and VOC's.
A facility shall not cause a discharge of
pollutants into the waters of the U.S. that
is in violation of the substantive
requirements of the NPDES under CWA
Section 402, as amended.
A facility or practice shall not cause
nonpoint source pollution of the waters of
the U.S. that violates applicable legal
substantive requirements implementing an
areawide or Statewide water quality
management plan approved by the
Administrator under CWA Section 208, as
amended.
Remedy implementation will
potentially involve discharges
of VOC's to the atmosphere
Emissions will be consistent
with federal and state
regulations.
No discharges under the
remedy are planned.  The
NPDES program is delegated
to Virginia  (VPDES)
Potentially applicable for
situations potentially not
covered by VPDES.

Potential future releases to
groundwater could migrate to
the stream.   Ongoing
monitoring will address the
requirement.

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                                                         APPENDIX C
                                      Applicable or Relevant and Appropriate Requirements
                                              Site 2 Fenced Ordnance Burial Area
                                                  NSWCDL, Dahlgren, Virginia
Criteria for
Classification of
Solid Waste
Disposal Facilities
and Practices

Water Quality
Standards
Water Quality
Standards
Water Quality
Standards
49 C.F.R.  257.3-4
       and Appendix I
       VR 680-15-02
      9 VAC 25-210-10
Applicable
 Relevant  and
Appropriate
       VR 680-15-02
      9 VAC 25-210-10
       VR 680-21-00
      9 VAC25-260-10
 Relevant  and
Appropriate
Applicable
 A facility or practice  shall  not  contaminate
an underground drinking water source
 beyond the solid waste  boundary or a court-
 or State-  established alternative.
 Criteria and standards  for groundwater
 quality.   Virginia regulation provides  basis
 for risk-based remediation and discharge
 limitations.
 Subsurface  borings  of all  types  shall  be
 constructed,  operated and  closed in a
 manner which  protects groundwater.
 Groundwater monitoring stations  shall  be
 located and constructed in a manner that
 allows  accurate  determination of
 groundwater quality and levels,  and
 prevents contamination of groundwater
 through the finished well hole or  casing.   All
 groundwater monitoring stations  shall  be
 accurately located utilizing latitude  and
 longitude by surveying,  or other acceptable
 means,  and coordinates shall be  included
 with all data collected.
Potential future releases to
groundwater could contaminate
groundwater over risk-based
criteria.  Ongoing monitoring
will address the requirement.

Provides basis for risk-based
decision making, establishes
standards for groundwater
quality.  Ongoing monitoring at
Site 2 will address the
requirement.

Completion of additional soil
borings, monitoring wells and
subsurface investigations will
be consistent with regulatory
requirements.

Completion of additional soil
borings, monitoring wells and
subsurface investigations will be
consistent with regulatory
requirements.

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                                                          APPENDIX C
                                      Applicable or Relevant and Appropriate Requirements
                                              Site 2 Fenced Ordnance Burial Area
                                                  NSWCDL, Dahlgren, Virginia
Pollution Discharge
Elimination System
(VPDES),  Virginia
Pollution
Abatement (VPA)
Permit Program
Water Quality
Standards
Water Quality
Standards
Virginia Standards
for Surface Water
VR 680-14-01
9 VAC 25-30-10
 Applicable
   VR 672-10-01
   VR 672-10-01
VR 680-21-01.14
 9 VAC 25-260-140
                   Relevant and
                   Appropriate
                   Relevant and
                   Appropriate
 Relevant and
Appropriate
Procedures and requirements for
discharging pollutants into surface waters,
or any activity which impacts physical,
chemical or biological properties of surface
waters.
                          Monitoring well design Standards.
                          Monitoring well Drillers certification.
Soil Cleanup levels will be developed by
using risk assessment or soil modeling
techniques to determine concentrations of
contaminants that can remain in soil such
that water in equilibrium with the soil will
not lead to natural discharge to surface
water resulting in an instream contaminant
concentration greater than the surface water
standard.
Capping of Site 2 is not
expected to produce waste
liquids that would be
discharged to surface waters
Any future activities or
groundwater monitoring  (e.g.
generation of purge water) will
address regulatory
requirements.

Completion of additional soil
borings, monitoring wells and
subsurface investigations will
be consistent with regulatory
requirements.

Completion of additional soil
borings, monitoring wells and
subsurface investigations will
be consistent with regulatory
requirements.

Cleanup criteria developed in
the Feasibility Study completed
for the site used risk assesment
and modeling techniques that
meet the requirements.

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                                                          APPENDIX C
                                      Applicable or Relevant and Appropriate Requirements
                                              Site 2 Fenced Ordnance Burial Area
                                                  NSWCDL, Dahlgren, Virginia
Water Quality
Standards
 VR 215-02-00
4 VAC 3-20-10
Applicable
All land disturbing activities must be in
compliance with local stormwater
management programs, where they exist.
Remediation activities must
meet requirements.

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