PB99-963918
EPA541-R99-061
1999
EPA Superfund
Record of Decision:
Naval Surface Warfare Dahlgren
Sites 19 and 29 OUs 13 and 14
Dahlgren, VA
9/27/1999
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SITE 19 - TRANSFORMER DRAINING AREA (SOILS)
AND
SITE 29 - BATTERY SERVICE AREA
(SOILS AND GROUNDWATER)
NAVAL SURFACE WARFARE CENTER
DAHLGREN SITE
DAHLGREN, VIRGINIA
RECORD OF DECISION
SEPTEMBER 1999
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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 DECLARATION STATEMENT REGARDING STATUTORY DETERMINATIONS 1-1
2.0 DECISION SUMMARY 2-1
2.1 SITE 19 - NAME, LOCATION, AND DESCRIPTION 2-1
2.2 SITE 19 - HISTORY AND ENFORCEMENT ACTIVITIES 2-1
2.2.1 History of Site Activities 2-1
2.2.2 Previous Investigations and Response Actions 2-5
2.2.3 Enforcement Actions 2-5
2.2.4 Highlights of Community Participation 2-6
2.3 SCOPE AND ROLE OF RESPONSE ACTION FOR SITE 19 2-6
2.4 SUMMARY OF SITE 19 CHARACTERISTICS 2-6
2.4.1 1995 Remedial Investigation 2-6
2.4.2 1999 Remedial Investigation/Feasibility Study 2-7
2.5 CURRENT AND POTENTIAL FUTURE SITE AND RESOURCE USES 2-8
2.6 SUMMARY OF SITE 19 RISKS 2-8
2.6.1 Environmental Evaluation - 2-12
2.6.2 Human Health Risks 2-12
2.7 DOCUMENTATION OF SIGNIFICANT CHANGES 2-17
2.8 SITE 29-NAME, LOCATION. AND DESCRIPTION 2-18
2.9 SITE 29 - HISTORY AND ENFORCEMENT ACTIVITIES 2-18
2.9.1 Historyof Site Activities, Previous Investigationsand Previous Response Actions 2-18
2.9.2 EnforcementActtons 2-20
2.9.3 Highlights of Community Participation 2-20
2 10 SCOPEAND ROLE OF RESPONSE ACTION FOR SITE 29 2-20
2.11 SUMMARY OF SITE 29 CHARACTERISTICS 2-21
2.11.1 1995 Remedial Investigation 2-21
2.11.2 Removal Action 2-21
2.11.3 1999 Remedial Investigation/Feasibility Study 2-23
2.12 CURRENT AND POTENTIAL FUTURE SITE AND RESOURCE USES 2-27
2.13 SUMMARY OF SITE 29 RISKS 2-27
2.13.1 Environmental Evaluation 2-27
2.13.2 Human Health Risks 2-28
2.14 DOCUMENTATION OF SIGNIFICANTCHANGES 2-35
3.0 RESPONSIVENESS SUMMARY 3'1
3.1 BACKGROUNDON COMMUNITY INVOLVEMENT 3-1
APPENDICES
A VIRGINIA CONCURRENCE LETTER
B PUBLIC COMMENTS
C TOXICITY PROFILES
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LIST OF TABLES
NUMBER
2'1 Maximum Detected Concentrations for COPCs (Post Removal), Site 19 2-11
2-2 Chemicals of Potential Concern and Exposure Point Concentrations, Site 19 2-13
2'3 Dose-Response Parameters, Site 19 2-14
2-4 Maximum Detected Concentrationsfor PCOCs, Site 29 2-25
2-5 Chemicals of Potential Concern and Exposure Point Concentrations, Site 29 2-29
2-6 Dose-Response Parameters, Site 29 ; . 2-30
LIST OF FIGURES
NUMBER ^
2-1 NSWCDL Location Map, Site 19 ....: 2-2
2-2 Site Location Map, Site 19 and 29 2-3
2-3 Site Map, Site 19 2-4
2-4 Rl Sampling Locations, Site 19 2-9
2'5 Post Removal Verification Sampling Locations, Site 19 2-10
2-6 Site Map. Site 29 2-19
2-7 Potentiometric Surface Map, Site 29 2-22
2-8 Post Removal Verification Sampling Locations, Site 29 2-24
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1.0 THE DECLARATION
1.1 SITE NAME AND LOCATION
Site 19, Transformer Draining Area and Site 29, Battery Service Area
Naval Surface Warfare Center Dahlgren Site
Dahlgren, Virginia
1.2 STATEMENT OF BASIS AND PURPOSE
This decision document focuses on remedial decisions and presents the selected remedial actions for Site
19 - Transformer Draining Area and Site 29 - Battery Service Area at the Naval Surface Warfare Center
Dahlgren Site (NSWCDL) Dahlgren, Virginia. 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 both sites.
The Commonwealth of Virginia concurs with the selected remedy (see Appendix A).
1.3 DESCRIPTION OF THE SELECTED REMEDY
The selected remedies for each site are as follows:
Site 19 Soil
No Further Action. PCB-contaminated soils were removed in 1994. Risk analysis conducted after the
removal revealed that residual risks to human health and the environment were within acceptable limits.
Groundwater at Site 19 will be addressed concurrently with adjacent Site 40 at a future date.
Site 29 Soil and Groundwater
No Further Action. Contaminated soils were removed in 1994. Risk analysis conducted after the removal
revealed that residual risks to human health and the environment were within acceptable limits.
1.4 DECLARATION STATEMENT REGARDING STATUTORY DETERMINATIONS
It has been determined that the Selected Remedy (no further action) for soil at Site 19 and soil and
groundwater at Site 29 is protective of human health and the environment, complies with Federal and
State requirements that are applicable or relevant and appropriate to the remedial action, is cost effective,
and uses permanent solutions and alternative treatment technologies to the maximum extent practicable
because previous removal actions have eliminated the need to conduct further remedial action.
The statutory preference for treatment as a principal element of a remedy is not applicable at these sites
because the residual risks are within an acceptable range and no further action is needed. A 5-year
review will not be required because constituents remaining onsite are at levels that do not require use
restrictions.
1-1
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CAPT. Vaughn E. Mahaffey/0
Commanding Officer '
Naval Surface Warfare Center
Dahlgren. Virginia
Abraham Ferdas, Director
Hazardous Site Cleanup Division
USEPA- Region III
Date
1-2
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2.0 DECISION SUMMARY
This Record of Decision (ROD) is issued to describe the Department of the Navy's (NAVY) selected remedial
action for both Site 19 - Transformer Draining Area and Site 29 - Battery Service Area, at the NSWCDL, in
Dahlgren, Virginia (Figure 2-1). Both sites are Installation Restoration (IR) sites (Figure 2-2) located at the
NSWCDL facility.
2.1 SITE 19 - NAME, LOCATION, AND DESCRIPTION
The Transformer Draining Area is located in the south-central portion of the NSWCDL property,
approximately 150 feet east of Caskey Road (Figure 2-3). Access to the site is provided via Caskey Road
and a paved drive to the south of Building 120B, the Property Disposal Office, which forms the northern
boundary of Site 19. The Building 120B Defense Reutilization and Marketing Office (DRMO) lot (Site 40),
located in the northeastern portion of the site, is surrounded by an approximately 7-foot-high chain-link fence,
and access is restricted. On the south are grassy areas.
The site is located on a relatively flat parcel of land, with elevations generally between 15 and 20 feet above
mean sea level (msl) and nearly level slopes (less than 3 percent). The ground surface at Site 19 is
characterized by a variety of surfaces, including pavement, gravel cover, and grass (Figure 2-3). Two
concrete pads are located approximately 10 feet directly southeast of Building 120B. In the past, a common
practice at NSWCDL was to drain transformer oil onto the ground behind Building 120B. The concrete pads
are the reported location where the transformers were drained.
Surface drainage at the site is overland either southeast or southwest to drainage ditches. These ditches
ultimately flow into storm sewers beneath the developed area to the southeast of Site 19.
2.2 SITE 19 - HISTORY AND ENFORCEMENT ACTIVITIES
2.2.1 History of Site Activities
The history of Site 19 has been developed from information provided in the Initial Assessment Study (IAS),
the Confirmation Study, and an analysis of Environmental Photographic Interpretation Center (EPIC) aerial
photographs. A summary of the site history is discussed in the following paragraphs.
Documentation of activity at Site 19 began as early as 1943 with the open storage of materials to the
north, south, and east around what is presently identified as Building 120B. Drainage of transformer oil
onto the ground behind Building 120B was a standard practice during the 1950s. The transformers were
then turned in to the Property Disposal Office. The IAS conducted in 1981 estimated that approximately
1,000 gallons of oil were involved; however, no data were available regarding polychlorinated biphenyl
(PCB) levels in the oil. Therefore, a Confirmation Study was recommended.
Ground-disturbing activities in the vicinity of Site 19 were first noted in the 1946 aerial photos and remain
evident in more recent aerial photographs. In the 1946 imagery, evidence of a trench was observed
approximately 75 feet southeast of Building 120B, the east end of which was located near a south-flowing
drainage channel. A pit was noted approximately 30 feet north of the trench. Evidence of a second pit,
containing an unknown liquid, was noted approximately 5 feet south of Building 120B and 15 feet west of
the concrete pads. The trench and pits were no longer visible in either 1952 and 1958.
2-1
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Source:
TF
DM
NAVFAC. 1993
May 99
ir DATE •
May 99
COCT/SCHOMKA :
1
0
•=1
JO 20'
caleinMiies
(Tfcj Tttn T*ch NUS, Inc.
LOCATION MAP
NSWCOL
OAHLGREN, VIRGINIA
fa cofrmACTNO. \ OWNER NO.
7188.-1801 , CTO261
tM**anDt/r7 jfSft "«re
IAF«»OWED«Y «^ "DATE
i
iDftAWUMMO.
i Figure 2-1
99
(WV.
0
2-2
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Swamp/March
Opan Watar
NSWCDL Boundary
Roads
Highways
Shaft ID
CONTRACT NCX
7188-1801
OWNER. N«L
CT0261
Tetra Tech NUS, Inc
SITE LOCATION MAP
SHMl9and29
COST/SCHEDJUttA
NSWCDL
DAHLQREN, VIRGINIA
SCALE
AS SHOWN
2-3
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DEFENSE REUTIUirATKW AMD IMRKCTMC OFUCE
(MMO) LOT (SITE 40)
LEGEND
x x * M Fence
DRAWNBV BUTE
TF May 99
CHECXIOIV OWE
DM May 99
COCT/tCHEDABEA
CCUJE
1 As Shown
f
| Tetra Tech NUS, Ine
Site Map
Site 19
NSWCDL
Dahlgren, Virginia
Map «o:G:\£UWgrmi\3Jl«19\fig2.car
2-4
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i^enCe,?n!T trenChf!i °ne '°Cated 75 feet east of Buildin9 120B and the °ther about 10 feet south of
Budding 120B, was noted ,n the 1960s images. An unknown liquid was evident in the eastern Trench
Neither trench was visible in the 1969 photographs. Astern irencn.
theneastem Stora9* a^a and on the south side of Building 1208 in the late
A n S' DmmS were observed °n Building 1208's east side in 1985 photographs
of Sna l?nS f 3 rectan9ular mounded area- was constructed in 1990 approximately 40 feet south
^^ from the fenced -a to a~
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2.2.4 Highlights of Community Participation
In accordance with Section 113 and 117 of CERCLA, the Navy provided a public comment period from
July 21, 1999 through August 19. 1999 for the proposed remedial action, which is described in the
Remedial Investigation/Feasibility Study and the Proposed Remedial Action Plan for Sites 19 and 29.
These documents were available to the public in the Administrative Record and information repositories
maintained at the Smoot Memorial Library, King George, Virginia; the NSWCDL General Library,
Dahlgren, Virginia; and the NSWCOL Public Record Room, Dahlgren, Virginia. Public notice was provided
in The Freelance Star newspaper on July 19, 1999 and The Journal newspaper on July 14, 1999, and a
public meeting was held in the King George Courthouse on July 28,1999. No written comments were
received during the comment period. Spoken comments and responses provided during the public
meeting are presented in Appendix B. Additional community involvement, including Restoration Advisory
Board (RAB) activities, are highlighted in Section 3.1.
2.3 SCOPE AND ROLE OF RESPONSE ACTION FOR SITE 19
Site 19 is one of many sites identified in the Federal Facility Agreement (FFA) for NSWCDL. In previous
years, RODs have been issued for several other sites in accordance with the priorities established in the Site
Management Plan (SMP). A removal was performed at Site 19 in 1994 to address PCB contaminated soils.
This action follows the removal and provides closure for the site soils.
The selected remedy (no further action for soils) fits the Navy strategy to reduce risks at all NSWCDL sites
with minimal long-term care. Site 19 soils are clean and require no future monitoring, allowing the Navy to
focus its resources on the remaining NSWCDL sites. The remedial action identified in this ROD addresses
contamination associated with Site 19 as identified in the Draft Final Rl Reports, Engineering Evaluation/Cost
Analysis Reports, Removal Action Reports, and the Addendum RI/FS Reports. The PCB-contaminated soil
was removed from the site and the subsequent risk analyses indicated the remaining risks are within
acceptable limits.
Future plans include addressing groundwater as part of adjacent Site 40.
2.4 SUMMARY OF SITE 19 CHARACTERISTICS
An RI/FS was completed in phases for Site 19. Sampling activities, consisting of soil sampling and the
installation and sampling of groundwater monitoring wells, were completed in 1994. Additional soil
sampling was performed before and after the removal action was completed in 1994. A draft final Rf was
prepared in 1995. An addendum RI/FS was prepared in 1999.
2.4.1 1995 Remedial Investigation
The Rl at Site 19 included a hydrogeologic investigation, contamination assessment, and risk assessment
The hydrogeologic investigation included the installation and sampling of two groundwater-monitoring wells
and the sampling of four existing groundwater-monitoring wells. Physical descriptions of the subsurface, a
monitoring well elevation and location survey, groundwater-level measurements, and two hydraulic
conductivity tests were also included in the hydrogeologic investigation. Site 19 is underlain by the Tabb
Formation, which is composed of sand, silt, and clay. Groundwater elevations based on March 1994
measurements were approximately 13 feet above msl. The shallow aquifer exists within a relatively thin sand
layer at Site 19 (approximately 10 feet thick), and predominant groundwater flow at the site is to the east
The estimated hydraulic conductivities at Site 19 were 7.29 x 10"3 cm/sec and 1.5 x 10"3 cm/sec.
The contamination assessment included the collection and analysis of samples from soil and groundwater.
Five surface soil samples, six subsurface soil samples, two samples from the concrete pads, and
2-6
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groundwater samples from six wells (two new and four existing wells) were collected during the field
investigation at Site 19.
Based on the results of the Rl, previous investigations, and historical information, RGBs were identified as
contaminants of primary concern at Site 19 because of potential human health risks. Risks to ecological
receptors were likely to be minimal because of the limited distribution of contaminants, and Site 19
provides minimal habitat for ecological receptors because of the heavy development and level of human
activity in the area. Soil sampling conducted during the Rl confirmed the presence of PCB contamination
east of Building 120B, as previously identified in the Confirmation Study. Surface soil, subsurface soil, and
groundwater samples collected beyond the previously identified area did not indicate contaminant
migration had occurred.
2.4.2 1999 Remedial Investigation/Feasibility Study
Follow-up remedial investigation activities consisting of a human health risk analysis were performed to
determine whether further action was required. These results are summarized below.
2.4.2.1 Sources of Contamination
Extensive soil sampling was conducted to identify the extent of PCB contamination in the area where
transformer oil was drained onto the ground during the 1950s. The amount of oil involved was estimated
to be approximately 1,000 gallons. Based on multimedia sampling, it was determined that the PCB
contamination was confined to the soil over an area covering approximately 25 ft. by 70 ft. to a depth of
2 ft. The PCB-contaminated soils were removed and disposed offsite in 1994 as part of the removal
action.
2.4.2.2 Description of Contamination
Soil sampling conducted during the Confirmation Study at Site 19 identified an area of shallow PCB
contaminated soil. No PCBs were detected in groundwater samples. The objective of the Rl at Site 19
was to determine the extent of contamination in both surficial and deeper soils and to verify that activity at
the site has not impacted groundwater quality. Phase 1 field investigation activities involved
inspection/evaluation and rehabilitation of the four existing IR monitoring wells at the site. Phase 2 field
activities included the installation of two new monitoring wells and the analysis of groundwater samples
from new and existing wells, soil sampling, and sampling of concrete chips from the existing concrete
pads.
The primary objective of the soil investigation at Site 19 was to identify the presence or absence of PCBs
and other contaminants in the vicinity of the transformer draining area. The objective of the groundwater
investigation was to determine whether PCBs had migrated from shallow soils into the surficial aquifer.
Surface water and sediment samples were not collected during the Rl investigation because of the
distribution of contamination in the soils, the immobile nature of PCBs, and the flat topography surrounding
Site 19. Transport of contaminated soil via surface runoff was not expected to be significant.
PCBs were the contaminants of primary concern at Site 19 based on previous investigations and historical
information. In addition to PCBs, samples were also analyzed for volatile and semivolatile compounds,
metals, cyanide, and total petroleum hydrocarbons (TPHs). Additional analyses were necessary because
it is not known what other materials were stored in the area. A Toxicity Characteristic Leaching Procedure
(TCLP) was completed on two soil samples to aid in evaluation of disposal options for soil at Site 19.
Rl soil samples that were collected outside the PCB-contaminated area where the removal action
occurred at Site 19 are shown in Figure 2-4. Post-removal verification sampling locations are shown in
Figure 2-5. Table 2-1 lists the chemicals of potential concern (COPC) for each medium and the maximum
concentration detected. The results of the sampling and analyses are presented below.
2-7
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«nd vTnS H t TH ""f^ 'ndudin9 aluminum' ars*™> cadmium, chromium, iron, manganese
and vanadium, detected m so.ls are identified in Table 2-1. The arsenic and iron concentrations reflect
backgroundI conditions based on statistical analyses. Low-level Aroclor-1260 concentrations ("ess than
the 1.0 mg/kg cleanup level) were detected in soil (2 ft. below ground surface [bgs]) after the removal
action was completed. The Aroclor-1260 contamination appears to be related to the past tranSml
draining practices, whereas the metals contamination does not
2.4.3.3
Contaminant Migration
The pnmary contaminant of concern at Site 19 was Aroclor-1260 in soils. Aroclor-1260 does not appear
to have migrated from the removal area via overland flow because none were detected in surface soil
°* fQL^°"tside the removal area. There also is no evidence of subsurface migration of
through leaching, because no Aroclor-1260 was detected in groundwater and none
nor™ HI H ™9 % '" ®ubsurface soil 2'ft b9s- Subsurface soils at Site 19 are only moderately
permeable and include a clay layer, helping prevent the vertical migration of Aroclor-1260 Aroclor-1260 is
unlikely to migrate via overland flow because the removal area was backfilled to existing grade with clean
soil. Aroclor-1260 is only slightly soluble in water, and the site topography is relatively flat.
Aroclor-1260 is not easily biodegradable and persists in the environment. The persistence of PCBs is '
dependent on the number of chlorine atoms that comprise the compound. PCBs with one or two chlorine
atoms degrade more readily than PCBs with three to six chlorine atoms. Aroclor-1260 contains more
chlorine by weight (60 percent) than any other commercially manufactured PCB product and therefore
would be expected to persist in the environment for a long time.
2.5 CURRENT AND POTENTIAL FUTURE SITE AND RESOURCE USES
Site 19 is located in the south-central portion of the Mainside, about 150 feet east of Caskey Road The site
is nearly'level A portion of the site is vegetated with grass and the remainder is covered with pavement or
gravel The site is bordered on the north by Building 120B. which is regularly occupied. A portion of this site
D erl? °l u £ fence Surroundin9 «ie DRMO Lot (Site 40). Access to the majority of Site 19 from Caskey
Road (which borders the site on the west side) is unrestricted. The site is bordered to the south and east bv
grassy fields. The base airstrip lies across Caskey Road immediately west of the site.
A portion of Site 19 lies within the fenced DRMO Lot and is entered by DRMO personnel on a sporadic basis
usually on a forklift to place or remove an item from storage. Other portions of the site have unrestricted
access and have occasional foot traffic and grounds maintenance activities performed Caskey Road is used
by base personnel for jogging and bike riding.
Site 19 is currently an industrial use area and is anticipated to remain an industrial use area in the future
The mission of the base is currently expanding and future potential for base closure and conversion to
residential land use is considered to be minimal. Groundwater in the shallow aquifer beneath Site 19 is
not a current source of drinking water. Groundwater contaminants will be evaluated in the future in
conjunction with an adjacent site (Site 40).
2.6
SUMMARY OF SITE 19 RISKS
The ecological and human health risks associated with exposure to contaminated media at Site 19 were
evaluated in the Addendum RI/FS Report.
2-8
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DEFENSE REUnUIZATON AND MARKETING OFFICE
(MHO) LOT (SITE 40)
REMOVAL AREA
CRASS AREA
SS/SB19-1
Legend
x x X Fence
Soil Sample Location
CONTRACT NO.
7188-1801
Tetra Tech NUS, Inc
Rl Sampling Locations
Site 19
COST/SCHEDAHEA
NSWCDL
Dahlgron, Virginia
SCALE
As Shown
Map «lo:G:\d«filgre
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Legend
• Floor Sample
A Wall Sample
ES-25
Source: OHM, 1995
TF
May 99
Tetra Tech NUS, Inc.
CONTRACT NO.
OWNER NO
CHECKED BY
DM
Mav99
Post Removal Verification Sampling Locations
COfiT/CCHED-AREA
DATE
A^MIOVED BY
SCAIE
As Shown
NSWCDL
Dahlgren, Virginia
DRAWING NO.
Figure 2-5
rk_iM*lM-cu217-fl5.jnil
2-10
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TABLE 2-1
MAXIMUM DETECTED CONCENTRATIONS FOR COPCs (POST REMOVAL)
SITE 19: TRANSFORMER DRAINING AREA
NSWCDL, DAHLGREN, VIRGINIA
SURFACE SOILS
Metals (mg/kg)
Aluminum
Arsenic
Chromium
Iron
Manganese
Vanadium
20,900
5.4
42.2
24,000
2,220
60.5
SUBSURFACE SOILS
Metals (mg/kg)
Aluminum
Cadmium
Chromium
Iron
Vanadium
Target Compound List (TCL) Pesticides/PCBs (mj
Aroclor-1260
102,000
4.1
105
37.000
125
3/kg)
0.81
2-11
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2.6.1 Environmental Evaluation
The PCB Aroclor-1260, aluminum, arsenic, and manganese are present in Site 19 surface soils in
concentrations greater than their respective soil background and ecological risk screening concentrations
Arsenic concentrations are not significantly different from background based on statistical analysis. The
three metals were detected in all five samples collected from this site, whereas Aroclor-1260 was only
present in one sample. Aluminum concentrations exceeded the conservative ecological risk screening
concentration used for this contaminant in all surface soil samples collected at this site. Arsenic and
manganese exceeded their ecological risk screening concentration in one and two samples, respectively.
These data suggest that although the presence of these contaminants represents a potential risk to
surface-dwelling ecological receptors, actual risk posed to ecological receptors is likely to be minimal Not
only as a result of the limited distribution of contaminants, but also because of the heavy development in
this area and the high level of human activity, this site represents minimal habitat for ecological receptors
These conditions limit the likelihood that ecological receptors will come in contact with these contaminants
and thus significantly reduce the risks associated with these contaminants.
2.6.2 Human Health Risks
Exposure Pathways and Potential Receptors
Base workers, construction workers, and onsite residents (children and adults) were evaluated as
potential receptors in the quantitative risk assessment Base workers were considered for current and
future conditions. Construction workers and onsite residents were evaluated for future conditions only
Although the potential for the base to be converted to residential land use is minimal, potential risks to
future onsite residents were quantified for purposes of completeness. Under the current and future land
use scenarios considered at Site 19, the exposure routes were incidental ingestion of soil and dermal
contact with soil.
The potential groundwater exposure route was not considered because contaminants in groundwater will
be addressed in conjunction with an adjacent site in the future. The potential inhalation of volatiles from
soil and inhalation of fugitive dust exposure route was not considered because the site is partially
vegetated, relatively flat, and/or covered with asphalt or gravel. Volatile organics are not COPCs at Site
19, and fugitive dust emissions would be minimal under current land use conditions. It is assumed that
good construction practices and moist soil at Site 19 (resulting from the shallow water table) will minimize
emissions of fugitive dust.
Exposure Assessment
The COPCs that were evaluated and their maximum exposure point concentrations are presented in
Table 2-2. Exposure point concentrations are used to determine potential human health risks.
Toxicity Assessment
The toxicity assessment characterizes the nature and magnitude of potential health effects associated with
human exposure to COPCs at each site. Quantitative risk estimates for each COPC and exposure pathway
are developed by integrating chemical-specific toxicity factors with estimated chemical intakes discussed in
the previous section.
Quantitative risk estimates are calculated using cancer slope factors (CSFs) for COPCs exhibiting
carcinogenic effects and reference doses (RfDs) for COPCs exhibiting systemic (noncarcinogenic) effects.
A summary of the RfDs and CSFs used in the baseline human health risk assessment is presented in
Tabte2-3.
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TABLE 2-2
CHEMICALS OF POTENTIAL CONCERN AND EXPOSURE POINT CONCENTRATIONS'1*
SITE 19, TRANSFORMER DRAINING AREA
NSWCDL, DAHLGREN, VIRGINIA
Organics
Chemical
Exposure Point
Concentration111
(mg/kg)
Inorganics
Chemical
Exposure Point
Concentration'11
(mg/kg)
Surface Soil (mg/kg)
Construction
Worker, Base
Worker, and
Future Residential
Scenarios
None
NA
Aluminum
Arsenic
Chromium
Iron *
Manganese
Vanadium
20,900
5.4
42.2
24,000
2,220
60.5
Subsurface Soil (mg/kg)
Construction
Worker, Base
Worker, and
Future Residential
Scenarios
Aroclor-1260
0.81
Aluminum
Cadmium
Chromium
Iron
Vanadium
102,000
4.1
105
37,000
125
Maximum concentrations are used as exposure point concentrations for soil for the
Reasonable Maximum Exposure (RME) and Central Tendency Exposure (CTE) because, with
the exception of the Aroclors, the post-removal soil database contains less than 10 samples.
The maximum detected Aroclor-1260 concentration was used as the exposure point
concentration for Aroclors because the information necessary to calculate the 95 percent
upper confidence limit on the mean was not available (i.e., sample quantitation limits for
nondetect results were not available).
2-13
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M
TABLE 2-3
DOSE-RESPONSE PARAMETERS
SITE 19: TRANSFORMER DRAINING AREA
NAVAL SURFACE WARFARE CENTER, DAHLGREN, VIRGINIA
Chemical
Aroclor-1260
Aluminum
Arsenic
Cadmium
Chromium VI (hexavatent)
Iron
Manganese • soil
Vanadium
1 USEPA, 1999a (IRIS
2 NA- Not available/a)
3 USEPA-NCEA provii
4 Values for high risk t
5 USEPA, 1997b
6 Assumed default val
7 ATSDR. 1991
8 ATSDR, 1993
9 USEPA, 1984
10 USEPA Region 1 Gu
RfDOral<"
(mg/kg-day)
NA">
1E+0<»
3E-4
SE-04
3E-3
3E-1
7E-3
>), unless otherw
jplfcabte. There
tional value, 199
ind persistence 1
je (USEPA, 198
dance. USEPA I
RfD
Inhalation")
(mg/kg-day)
NA
1E-3"'
NA
NA
3E-5
NA
1.43E-5
NA
ise noted.
are currently no
«a
>ased on USEPA
9)
*isk Uodates No
CSF Oral'"
(kg-day/kfl)
1.0E+0:CTE<4>
2.0E+0:RME(4)
NA
1.5E+0
NA
NA
NA
NA
NA
published values for
guidance for evalu.
vemhar IQQfiri "Th
CSF
Inhalation"'
(kg-day/mg)
1.0E+0:CTE'4'
2.0E+0:RME<4>
NA
1.51E+1
6.3E+0
4 1F+.i(5)
NA
NA
NA
parameters.
iting carcinogenic rig
Gastrointestinal
Absorption
Factor
NA
0.05<«>
0.95m
0.05
NA
0.03"°'
0.05<"
ks from PCBs (USEP
RfD Dermal
(mgftg-day)
NA
5.0E-2
2.85E-4
2.5E-5
3.0E-5
3.0E-1
4.2E-3
3.5E-4
A, 1996b).
CSF Dermal
(kg-day/mg)
NA
NA
1.S8E+0
NA
NA
NA
NA
NA
Weight of
Evidence
B2
NA
A1 - Inhalation
B1 - Inhalation
A1 - Inhalation
NA
D
D
USEPA's Weight of Evidence Classifications:
A1 Known human carcinogen.
B1 Probable human carcinogen; limited human data are available
Probable human carcinogen; sufficient evidence in animals and inadequate or no evidence in humans
Possible human carcinogen.
Not classifiable as to human carcinogenicity.
B2
c
D
.
-------
CSFs and RfDs developed by USEPA are based on ingestion (bral) or inhalation routes of exposure rather
than dermal contact. Therefore, these values reflect administered doses rather than absorbed doses
USEPA guidance on assessment of dermal exposure (USEPA, 1992b) recommends that oral toxicity factors
used in dermal risk assessment be adjusted for gastrointestinal absorption efficiency, if such data are
available. The methodology for the adjustment is presented in Appendix A to the USEPA Risk Assessment
Guidance to Superfund, Part A (USEPA. 1 989). The dermal RfDs and CSFs adjusted for Gl absorption are
listed in Table 2-3.
Chromium Toxicity
Chromium was identified as a COPC in surface soil and subsurface soil at Site 19. Analytical results for
this chemical are reported as total chromium. Chromium may be present in different oxidation states. The
hexavalent state, which is a less common state of chromium in environmental matrices, is the most toxic
form of chromium. No analyses were performed to distinguish between the specific chromium oxidation
states present at the site. For the purposes of this risk assessment, it is conservatively assumed that
chromium is present in the hexavalent state.
Toxicity profiles for COPCs are presented in Appendix C.
Risk Characterization
Excess lifetime cancer risks are determined by multiplying the intake level with the cancer slope factor.
These risks are probabilities that are generally expressed in scientific notation (e.g., 1x10*). An excess
lifetime cancer risk of 1 x 10* 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 (i.e., water, soil,
or air) is expressed as the hazard quotient (HQ) (or the ratio of the estimated intake derived from the
contaminant concentration in a given medium to the contaminant's RfD). 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.
Base Worker. The cumulative noncancer His for ingestion of and dermal contact with soils for Site 19
under industrial land use conditions are less than 1, which indicates that no significant hazards are
associated with soils at Site 19.
The cumulative ingestion and dermal contact cancer risk is I.SxIQ-6, under a "reasonable maximum
exposure" (RME) scenario. Although the incremental cancer risk for the base worker slightly exceeded
1x10*. it is within USEPAs target risk range of 1x10-*to "6
Construction Worker. The cumulative noncancer His for ingestion of and dermal contact with soils for
Site 19 under industrial land use conditions are 1.2 for the RME. The HI for the RME exceeds one
primarily as a result of the ingestion of aluminum and iron in subsurface soil. The RfDs for aluminum and
iron are not based on any health effects but rather on recommended daily allowances. If aluminum and
iron were eliminated as COPCs, the HI calculated for the construction worker would be 0.36, which is less
than one. If the toxicity criterion for bivalent chromium was used in the risk assessment, the HI calculated
for the construction worker would be 0.96, which is also less than one. A HI of less than one indicates no
significant hazards. Also, His calculated on target organ/endpoint specific basis do not exceed unity
indicating that adverse health effects are not anticipated for construction workers exposed to subsurface
soil.
2-15
-------
The cumulative ingestion and dermal contact cancer risk is 4.1x10-7, under a RME scenario, which is less
than USEPA's target risk range of 1x10^to 1x10*.
Future Resident. The cumulative noncancer His for ingestion of and dermal contact with soils for Site 19
under hypothetical residential land use conditions are 2.6 for the RME. The HI for the RME exceeds one
primarily as a result of the ingestion of aluminum, arsenic, chromium, and iron in soil. The RfDs for
aluminum and iron are not based on any hearth effects but rather on recommended daily allowances. It
was conservatively assumed that all chromium is hexavalent chromium, which significantly overestimates
the potential risks from exposure to chromium. If aluminum and iron were eliminated as COPCs, and
chromium was assumed to be trivalent chromium, the HI calculated for the hypothetical resident is 0.7,
which is less than one. A HI of less than one indicates no significant hazards.
The total residential incremental lifetime cancer risk based on cumulative ingestion and dermal contact
with soils is 1.4x10's, under a RME scenario, which is within USEPA's target risk range of 1x10^ to
1X10-6.
Uncertainty Analysis
The major sources of uncertainty specific to post-remedial conditions at Site 19 include:
• The exposure point concentrations for iron and arsenic (noncarcinogenic risk drivers for
soil) may reflect background conditions. In addition, the RfDs for iron and aluminum are
not based on any health effects but rather on recommended daily allowances.
Consequently, some USEPA Regions (e.g., USEPA Region I) do not advocate
quantitative risk assessment of these metals. If these constituents (aluminum, arsenic,
and iron) are eliminated as COPCs in surface soil, the HI for the most sensitive receptor,
the hypothetical future child resident, would be 0.83, which is less than the USEPA
benchmark of one. If aluminum and iron are eliminated as COPCs in subsurface soils,
the HI calculated for the hypothetical child resident would be 1.6. Additionally, if
chromium was evaluated as trivalent chromium, the HI for the child exposed to surface
soil would be 0.61, and the HI calculated for the child exposed to subsurface soil would be
0.44.
• An evaluation of the risk estimates for chromium indicate that the risk for dermal contact
with soil contributes more to the total HI for chromium than risk estimates for the ingestion
route of exposure. The risk estimate for dermal contact results from a conservative oral
absorption factor (0.01) provided by USEPA Region III that has been used to calculate a
dermal RfD for chromium. The USEPA has recently published an oral absorption value of
0.025 for hexavalent chromium. Consequently, risks from dermal absorption to chromium
may be overestimated by a factor of 2.5.
• Arsenic, the only carcinogenic constituent identified as a COPC in surface soil, may be
present at concentrations reflecting background conditions. If arsenic was eliminated as a
COPC in surface soil, a cancer risk estimate would not be calculated for surface soils.
Summary and Conclusions
The following items summarize the results of a human health risk assessment conducted based on the
post-removal action soil database for Site 19:
1. Hazard indices calculated for base workers who are exposed to soil do not exceed one
indicating that adverse health effects are not anticipated under the conditions established
in the exposure assessment. Cancer risk estimates developed for this receptor exceed
1.0 X 10* only when arsenic concentrations in surface soil are evaluated. However, the
2-16
-------
results of statistical comparisons of site concentrations with background concentrations
indicate that the arsenic concentrations in the Site 19 soils are reflective of background
conditions.
2. His calculated for the construction worker exposed to surface soil and subsurface soil are
0.61 and 1.2 for the RME receptor exposed to surface and subsurface soils, respectively.
The primary noncarcinogenic n'sk drivers are aluminum and iron; however, significant
uncertainty is reported for the available RfDs for aluminum and iron. The provisional oral
RfDs available for these metals are based on allowable daily intakes for human nutrition,
instead of an adverse health effect. Additionally, these metals do not affect the same
target organs. Consequently, target organ/effect specific His would not exceed unity.
Cancer risk estimates for the construction worker do not exceed 1E-6.
3. A hypothetical future resident was evaluated for purposes of completeness. The His
calculated assuming exposure to surface and subsurface soil were 2.5 and 4.9,
respectively. Arsenic (surface soil), aluminum, iron, and chromium are the primary risk
drivers. However, His calculated for these metals overestimate the site-related,
noncarcinogenic risk: a) Arsenic concentrations in the surface soil reflect background
conditions, b) The provisional RfDs available for aluminum and iron are not based on
adverse health effects, and c) The risk assessment was prepared assuming that 100
percent of the chromium was present in the soil in the hexavalent state.
4. Cancer risk estimates developed for the hypothetical future resident (RME case) are 1.4
X 10's and 4.1 X 10"6 for surface and subsurface soils, respectively. Cancer risk
estimates developed for the CTE case are 1.7 X 10"6 and 3.0 X 10'7 for the surface and
subsurface soils, respectively. Arsenic, detected at concentrations reflecting background,
is the only COPC contributing to the risks calculated assuming surface soil exposure.
Aroclor-1260, detected at concentrations less than the current USEPA soil screening level
(SSL) for PCBs (for residential land use), is the only contaminant of potential concern
(COPC) contributing to the risks calculated assuming subsurface soil exposure.
The cancer risk estimates for the human receptors evaluated are within or less than the USEPA target risk
range of 1 X 10"* to 1 X lO*. The maximum concentration of the primary site contaminant (i.e., the PCBs)
is less than the USEPA SSL for residential land use. The His calculated for the base worker and the
construction worker do not exceed one. His calculated for the hypothetical future resident, which are less
than five, are expected to overestimate the site-related, noncarcinogenic risk to this receptor.
The Rl conducted for Site 19 indicated PCBs in soil were the only contaminant that warranted remedial
action. Subsequently, the PCB-contaminated soil was excavated and disposed of offsrte. Sampling data
was collected to verify the removal action achieved its objective. This data was evaluated in a revised risk
assessment which indicated remaining risks are acceptable.
Therefore "no further action" is the selected remedy for soils at Site 19. Groundwater will be further
evaluated in conjunction with an adjacent site (Site 40).
2.7 DOCUMENTATION OF SIGNIFICANT CHANGES
The selected remedy is the same alternative identified as the recommended alternative in the Proposed
Remedial Action Plan which was presented to the public at the public meeting held July 28,1999.
There were no significant changes to the recommended remedial action alternative in the Proposed Plan.
2-17
-------
2.8 SITE 29 - NAME, LOCATION, AND DESCRIPTION
The Battery Service Area, located off Caskey Road in the south-central portion of the NSWCDL Mainside
consisted of a former unlined neutralization pit used for disposal of battery acid resulting from handling and
recharging of sulfunc acid batteries (Figure 2-6). The exact depth and width of the pit are unknown The
former pit, located behind Buildings 1121 and 338, was paved over and the location is used as a service
area. Access to the pit was through a concrete manhole type cover. The pit was closed in the mid-1980s
and was not backfilled, although the manhole was covered with soil. The site, which is heavily developed
and composed of closely spaced structures and pavement, is used by the Public Works Department mainly
for the maintenance of heavy equipment and transportation vehicles. A grease rack is located approximately
5 feet west of the former pit and is currently used for the maintenance and lubrication of heavy machinery
The majority of the base maintenance vehicles (e.g., plows, dump trucks, buses, etc.) are parked
approximately 200 feet north of the site. The base golf course, which is separated from the Public Works
area by a chain-link fence, is located approximately 150 feet west of the site. The base Cooling Pond Site
55 is located approximately 250 feet south of the site. Access to the site is provided via Caskey Road which
is located approximately 200 feet east of the site. au,w,,,w,
Elevations in the site vicinity are between 10 and 20 feet msl. Slopes are gentle (less than 3 percent) and
surface drainage is overland to storm drains, which discharge to the Cooling Pond (Site 55).
Several Solid Waste Management Units (SWMUs) are in the vicinity of Site 29, including the following:
• Cooling Pond (Site 55);
• Battery Locker Acid Draining Area (SWMU 98);
• Building 155 Auto Shop Waste Oil Filter and Underground Storage Tank (UST) (SWMU
• Oil/Water Separator(OWS) 1121-Old (SWMU 128);
• Building 1121 Former Waste Oil UST (SWMU 78);
• SWMU 127: OWS 1121-300, OWS 115-350, OWS 402-30,000, and OWS 486-1000
(SWMU 127).
2.9 SITE 29 - HISTORY AND ENFORCEMENT ACTIVITIES
2>9>1 History of Site Activities. Previous Investigations and Previous Response Actions
The site history for Site 29 has been developed from information provided in the IAS, the Confirmation
Study, and an EPIC analysis of aerial photographs. A summary of the site history is discussed in the
following paragraphs.
Information contained in the IAS was obtained through onsite records review, site visits and personnel
interviews conducted during 1981. Waste battery acids were reported to have discharged into an
underground tank at Site 29 at the rate of approximately 10 to 15 gallons per month. The tank was
apparently never emptied and, despite numerous inquiries by Fred C. Hart Associates Inc no indication
showed where the tank drained. At the time of the IAS, a dye test program was being developed and
implemented by the base to determine discharge from the tank. The IAS did not recommend a
Confirmation Study at Site 29 because of the planned dye test program.
2-18
-------
, Approximate
1 Location of
: Neutralization
P
2-19
-------
During a site reconnaissance for the Rl in March 1989 the results of the dye test were discussed, and it
was concluded that no tank existed at this site. When the area was investigated, a concrete manhole (ike
cover was removed and an unlined limestone-filled pit was found. When the investigation was completed,
the pit was not backfilled, but the manhole was covered with soil. The top of the limestone in the pit was
observed to be within approximately 2 feet of the surface. Use of the pit ceased around 1985.
Analysis of aerial photographs of NSWCDL indicates that a concrete building, a bunker, and open service
yard areas, all of which were accessed by Caskey Road, were located in the present-day Battery Service
Area as early as 1937. Evidence of what appeared to be a pit in the Battery Service Area was first noted
in the 1952 imagery, and it remained apparent in the photography as late as 1977.
An RI/FS was completed in phases for Site 29. Sampling activities, consisting of soil sampling, surface
water and sediment sampling, and the installation and sampling of groundwater monitoring wells were
completed in 1994. Additional soil sampling was performed before and after the removal action that was
completed in 1997. A draft final Rl was prepared in 1995. An addendum RI/FS was prepared in 1999.
In 1997, a removal action was performed and is described in Section 2.11.2.
2.9.2 Enforcement Actions
No enforcement actions have been taken at Site 29. The Navy has owned this property since 1918 and is
identified as the responsible party. NSWCDL was added to the NPL in 1994.
2.9.3 Highlights of Community Participation
In accordance with Section 113 and 117 of CERCLA, the Navy provided a public comment period from
July 21, 1999 through August 19, 1999 for the proposed remedial action described in the Remedial
Investigation/Feasibility Study and the Proposed Remedial Action Plan for Sites 19 and 29.
These documents were available to the public in the Administrative Record and information repositories
maintained at the Smoot Memorial Library, King George, Virginia; the NSWCDL General Library,
Dahlgren, Virginia; and the NSWCDL Public Record Room, Dahlgren, Virginia. Public notice was provided
in The Freelance Star newspaper on July 19, 1999 and The Journal newspaper on July 14, 1999 and a
public meeting was held in the King George Courthouse on July 28, 1999. No written comments were
received during the comment period. Spoken comments and responses provided during the public
meeting are presented in Appendix B.
Additional community involvement, including Restoration Advisory Board (RAB) activities, are highlighted
in Section 3.1.
2.10 SCOPE AND ROLE OF RESPONSE ACTION FOR SITE 29
Site 29 is one of many sites identified in the Federal Facility Agreement (FFA) for NSWCDL. In previous
years, RODs have been issued for several other sites in accordance with the priorities established in the Site
Management Plan (SMP). A removal was performed at Site 29 in 1997. This action follows the removal and
provides closure for the site.
2-20
-------
The selected remedy (no further action) fits the Navy strategy to reduce risks at all NSWCDL sites with
minimal long-term care. Site 29 soils are clean and require no future monitoring, allowing the Navy to
focus its resources on the remaining NSWCDL sites. Soils at Site 29 are acceptable under the residential
use scenario. Groundwater sampling at Site 29 indicated levels of metals that exceeded Maximum
Contaminant Levels (MCLs); however, upgradient monitoring revealed that concentrations of these metals
entering the site were at the same level or higher. It was determined in the RI/FS that Site 29 was not
likely contributing to these concentrations.
2.11 SUMMARY OF SITE 29 CHARACTERISTICS
The RI/FS and removal action are summarized below.
2.11.1 1995 Remedial Investigation
The Rl at Site 29 included a hydrogeologic investigation, contaminant assessment, and risk assessment.
The hydrogeologic investigation included the installation and sampling of one shallow groundwater monitoring
well and the sampling of two existing shallow groundwater monitoring wells. Physical descriptions of the
subsurface, a monitoring well elevation and location survey, groundwater-level measurements, and hydraulic
conductivity testing were also included in the hydrogeologic investigation. Two soil borings, including one
used for the completion of groundwater monitoring well GW29-2 (depth of 16 ft bgs), were completed in the
immediate vicinity of the former pit. The subsurface in these borings consists predominantly of clayey sand
(possible fill) to approximately 10 feet underlain by clay extending to the bottom of the borings (12 and 20 ft
bgs). A defined saturated zone was not encountered in either of the two new borings. Predominant
groundwater flow at the site is to the south-southwest (Figure 2-7). The estimated hydraulic conductivity in
GW29-2 was 4.9 x 1Q* cm/sec.
The contamination assessment included the collection and analysis of samples from subsurface soil and
groundwater. Eight subsurface soil samples were collected from two locations within the immediate vicinity
of the pit (borings SB29-1 and SB29-2, completed to 10 feet bgs). Groundwater samples were collected from
the three wells. All samples were collected during the Phase 2 field investigation.
No organic compounds were detected in the groundwater samples at concentrations that exceeded either
the MCLs or the Region III Risk-Based Concentration (RBC) screening values for tap water. Arsenic,
beryllium, lead, nickel, and zinc were detected in the unfiltered groundwater samples at this site at maximum
concentrations that exceeded either the MCLs and/or the Region III criteria; therefore, the untreated
groundwaterat this site may be considered to be unsuitable for potable use.
2.11.2 Removal Action
A removal action was completed at Site 29 in 1997 and consisted of removal and disposal of the metals
contaminated soil. (The neutralization pit had been removed during a 1996 Rl sampling effort.) Soils
contaminated with metals (antimony, arsenic, iron, lead, and mercury) and petroleum hydrocarbons were
excavated and transported to the King & Queen Landfill located in Little Plymouth, Virginia for disposal.
Target clean-up levels were based on USEPA Risk-Based Concentrations (RBCs) for metals and the
VADEQ action level for Total Petroleum Hydrocarbon (TPH). Approximately 200 cubic yards of
contaminated soil were removed. The entire excavation was approximately 21.5 ft. by 38 ft. by 7 ft. deep.
Soil sampling and analyses were conducted from the sides and bottom of the excavation to confirm that all
soil with concentrations greater than or equal to target clean-up levels was removed. Except for arsenic,
target clean-up concentrations were achieved at Site 29. Arsenic concentrations of 6.87, 7.62, and 7.64
(mg/kg) were detected at three sample locations. The excavation was then backfilled and covered with
asphalt pavement.
2-21
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APPROXIMATE LOCATION
OF NEUTRALIZATION P
STORMWATER 9.00
OUTFALL
LEGEND
Monitoring W.IHGW)
Subwrfic* Soil Boring (SB)
Pottntiomttric Surfic* Contour*
DKAWNBV
TF
DATE
May 99
Tetra Tech NUS, inc.
CONTRACT Na
OWNER NQ
CT0261
CHECKED K
DM
OWTE
May 99
COST/SCHEDWUttA
CCAl£
A* Shown
Potentiometric Surface Map
Site 29
NSWCDL
Dahlgren, Virginia
APPROVED IV
DATE
APPROVEDtY
DATE
MAWMONO.
Figure 2-7
REV.
2-22
Map fito:G.UahlgnntMt29\poMnuo >urfw*.cdr
-------
2.11.3 1999 Remedial Investigation/Feasibility Study
Follow-up remedial investigation activities consisting of a human health and ecological risk analysis was
performed to determine whether further action was required. These results are summarized below.
2.11.3.1 Sources of Contamination
Extensive soil sampling was conducted to identify the extent of contamination near the neutralization pit.
The only known waste to have been disposed of at Site 29 is battery acid, which was discharged to an
unlined neutralization pit through a concrete manhole cover. Acid disposal into the pit ceased around
1985, at which time the pit was not backfilled. The neutralization pit was removed in 1996. The
contaminated soil was removed in 1997 as part of the removal action.
2.11.3.2 Description of Contamination
Soil and groundwater sampling was conducted under the Rl because of the reported discharge of liquid
battery acid into an unlined neutralization pit. Initial data needs included the inspection, evaluation, and
rehabilitation of the existing monitoring wells originally installed in the vicinity of Site 29 as part of UST
studies. These field activities were completed in June 1993 as part of the Phase 1 field activities under
the Rl. Phase 2 activities included the collection of soil samples, the installation of an additional
groundwater monitoring well, and the collection of groundwater samples from new and existing monitoring
wells.
Two main objectives were identified for the Rl at Site 29. Subsurface samples were collected to determine
the presence or absence of residual contamination in the pit and surrounding soils. In addition,
groundwater samples were collected to determine the presence or absence of contaminants in the shallow
aquifer resulting from potential migration of wastes from the pit Depth and direction of groundwater flow
were also determined as part of the Phase 2 Investigation.
The analytical parameters selected for soil and groundwater samples from Site 29 included volatile and
semivolatile organic compounds, metals, cyanide, TPHs, and sulfate. Groundwater samples were also
analyzed for hardness. The identified parameters were selected as representative constituents likely to be
present because of the types of wastes disposed in the area. Volatile and semivolatile compounds,
metals, and cyanide were included because these constituents may be present from operations at the
adjacent grease rack. TPH was included because of operations at the grease rack and the former USTs
in the area. Sulfate analysis was included based on disposal of sulfuric acid in the pit. Lead was a
concern because it may have been dissolved in the battery acid. Determination of pH in groundwater
samples provided a simple analytical tool for indicating the presence of residual acidity.
Soil samples collected during the 1995 Rl indicated metals contaminated soils in the vicinity of the
neutralization pit. (Soil in these sample areas was excavated and transported offsite for disposal during
the 1997 removal action.) In addition, groundwater samples, shown in Figure 2-7, were collected as part
of the 1995 Rl. Post removal verification soil samples, shown in Figure 2-8, were collected from the side
walls and bottom of the excavation area after the removal action was completed in 1997. Table 2-4 lists
the chemicals of potential concern for each medium and the maximum concentration detected. The
results of the sampling and analyses are presented below.
Subsurface Soils
Benzo(a)pyrene, arsenic, and chromium were detected in subsurface soils as shown in Table 2-4.
Benzo(a)pyrene was detected in one of the five samples at a concentration of 160 jig/kg, above the
residential Risk-Based Concentrations (RBC) screening level of 87ng/kg. The arsenic concentrations
2-23
-------
RACK
L • 9 • n rt
EXCMMTKIN AREA
A aOM SAMPLES
• S»t«*aS TAKEN 4' SaOW OR*D£
• SIOOMUS TAKtN r BELOW CRADC
S C A 1 F
PJD««giwSit«m»mo»«*«>.i 6
f!7
-
BUILDING 1121
SAMPLES
r 1 DA29-046
2 DA29-047
3 DA29-048
4 DA29-049
5 DA29-050
6 DA29-051
7 DA29-052
8 DA29-053
9 DA29-054
10 DA29-055
11 DA29-056
12 DA29-057
13DA29-058
14 UA29-U59
15 DA29-060
16 DA29-061
17 DA29-062
18 DA29-068
Source: OHM. 1997
E
••
••wd
50 FEET
WLR May 99
DM
May 99
AS SHOWN
1
®Tetra Tech NUS, Inc.
Post Removal Verification Sampling Locations
Site 29
NSWCDL
Dahlgren, Virginia
CONTRACT NO.
7188-1601
APt^OVfeOBV^^^^ ^
Figure 2-8
OWNER NO.
lz*
-------
TABLE 2-4
MAXIMUM DETECTED CONCENTRATIONS FOR COPCs (POST REMOVAL)
SITE 29: BATTERY SERVICE AREA
NSWCDL, DAHLGREN, VIRGINIA
SUBSURFACE SOILS
Organics (mg/kg)
Benzo(a)pyrene
0.16
Metals (mg/kg)
Arsenic
7.64
Chromium
37.7
GROUNDWATER
Organics (mg/L)
Benzene
0.001
Metals (mg/L)
Aluminum
9.71
Arsenic
0.0064
Iron
23.2
Lead
0.113
Manganese
Nickel
Zinc
2.62
0.0749
1.57
2-25
-------
marginally exceeded background. The maximum and average site concentrations were 7.64 mg/kg and
4.2 mg/kg, respectively. The maximum background concentration of arsenic was 3.3 mg/kg Chromium
was detected at a maximum concentration of 37.7 mg/kg, above the residential RBC screening level of 23
mg/kg. The maximum background concentration of chromium is 18.5 mg/kg.
Groundwater
Benzene, aluminum, arsenic, copper, iron, lead, manganese, nickel, and zinc were detected in
groundwater and maximum concentrations are presented on Table 2-4.
Surface Water and Sediment
Surface water and sediment samples were collected from the Cooling Pond (Site 55) in support of the Rl
for Site 55. These results will be addressed in the Site 55 Rl.
2.11.3.2.1 Contaminant Migration
The predominant COPCs were metals. Before the removal action, several metals detected in subsurface
soils in the vicinity of the former pit area exceeded metal concentrations in background soil samples
These constituents are believed to have been the result of past practices in the neutralization pit
Groundwater transport was the only potential migration pathway for these constituents because the
contaminated soils were covered by asphalt pavement. COPCs identified in groundwater included
aluminum, arsenic, copper, iron, lead, manganese, nickel, and zinc.
Subsurface soils of the saturated zone at Site 29 vary between clay with fine sand to silly clay. Inorganic
constituents exhibit low mobility in clay and silty clay soils. The ability of soils to absorb inorganic
constituents increases with an increase in surface area and clay content of soil grains. The mobility of
zinc may vary between low to moderate in sandy clay and clay soils. The mobility of copper is expected to
be low in clay and sandy clay soils. In addition, the hydraulic conductivity of the saturated soils at Site 29
was estimated to be 1.0 x 10's cm/sec indicating low groundwater velocities.
If sufficient acid waste is added to depress the soil pH to less than five, then soils generally lose their
ability to retain metals. More acidic soil conditions could therefore result in increased mobility of inorganic
constituents in soil. The pH of the subsurface soils and groundwater at Site 29 varied between five and
six. These pH levels are similar to values detected at the other IR sites at NSWCDL Therefore, disposal
activities at Site 29 do not appear to have significantly altered pH levels in soil and groundwater.
Based on the soil characteristics, the potential for mobility of inorganic constituents at Site 29 appears to
be low. Considering the retardation of contaminants in clay soils and low groundwater velocity,
mobilization and transport of inorganic constituents could be occurring at a slow rate at Site 29.
Groundwater at Site 29 appears to be discharging into the Cooling Pond located downgradient of
monitoring well GW 29-4 (see Figure 2-7). The potential for the migration of inorganic constituents to the
Cooling Pond (from the former neutralization pit) was evaluated using a fate and transport model. Potential
transport to surface water and sediment in the Cooling Pond was evaluated for groundwater COPCs
identified in the ecological risk assessment (aluminum, copper, lead, manganese, and zinc). Transport of
these constituents from subsurface soil to groundwater to the Cooling Pond was assessed using the
residual soil concentrations and existing groundwater concentrations. Surface water dilution was based
on runoff from the area draining into the upper leg of the Cooling Pond and a precipitation rate of 40 in/yr.
The groundwater discharge face was assumed to be the entire length along the upper leg of the Cooling
Pond (600-ft). No dispersion from the source area to the discharge point was conservatively assumed.
Based on the evaluation, groundwater concentrations are not expected to negatively impact surface
waters or sediments in the Cooling Pond.
2-26
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2.12 CURRENT AND POTENTIAL FUTURE SITE AND RESOURCE USES
Site 29 is located in the south-central portion of the Mainside in the public work area. The site is located
behind Buildings 338 and 1121 and can be accessed via the road servicing these buildings. Buildings to the
north, south, and east, and a chain-link fence to the west border the site.
The site is paved, which limits the possibility of contact with contaminated materials. Immediately west of
the fence is the base golf course. Land within a 0.5 mile radius of the Battery Service Area is mainly
developed for residential and base support activities. Public works and operations areas of the base lie to the
north, south, and east of the site. Residences are located with in 1,000 feet of the site. Roads adjacent to the
site are used by base personnel for jogging and bike riding. In addition, fishing is allowed in the Cooling
Ponds on a catch and release basis. A golf course is located just south of the site in the residential area.
The buildings surrounding Site 29 are regularly occupied by base personnel. However, no significant activity
happens outside the buildings. Access to the site is restricted on three sides because of the presence of
buildings. However, the west side allows unrestricted access from within the inner security perimeter. Site
29 is currently an industrial use area and is anticipated to remain an industrial use area in the future. The
mission of the base is currently expanding and future potential for base closure and conversion to
residential land use is considered to be minimal.
The watertable (or Columbia) aquifer beneath Site 29 is a thin water bearing zone underlain by a laterally
persistent clay confining layer (or Upper Confining Unit). Shallow groundwater at the Base is known to
discharge to adjacent shallow water bodies, in this case the manmade Cooling Pond located
approximately 250 ft. from Site 29. The watertable aquifer at the Base is generally of poor quality because
of high, naturally occurring concentrations of some metals (i.e. iron and manganese) according to a United
States Geological Survey (USGS) study of basewide groundwater quality. Poor water quality, coupled
with the thin saturated thickness and locally high percentages of fine grain sediments, effectively
diminishes the feasibility of using the watertable aquifer as an industrial or potable water source.
However, in the risk evaluation for Site 29, the watertable aquifer is considered to be a potential source of
potable water.
2.13 SUMMARY OF SITE 29 RISKS
The ecological and human health risks associated with exposure to contaminated media at Site 29 were
evaluated in the Addendum RI/FS Report. The residential use scenario was evaluated for completeness;
although the site is anticipated to remain in industrial use.
2.13.1 Environmental Evaluation
During the 1995 Rl, an Ecological Risk Assessment was conducted. It concluded that shallow
groundwater associated with Site 29 flows toward the Cooling Pond (located nearby and to the south of
the Battery Service Area) and likely discharges into the pond. This is the primary mechanism for transport
of contaminants from the Battery Service Area because the surface soils in the vicinity of the Battery
Service Area are paved over and not exposed. Ecological receptors inhabiting or using the Cooling Pond
may come in contact with potential contaminants entering the pond via groundwater discharges
associated with Site 29. Aluminum, lead, manganese/and zinc were identified as COPCs in groundwater.
To investigate these exposure pathways, samples of groundwater and subsurface soils were collected
from the site, which are summarized in Table 2-4. Based on current conditions at Site 29 and fate and
transport modeling of groundwater constituents, it is unlikely that ecological receptors will come in contact
with any contaminants present in these two media; therefore, risks to ecological receptors are believed to
be minimal, requiring no further action.
2-27
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2-13.2 Human Health Risks
Exposure Pathways and Potential Receptors
Base workers, construction workers, and onsite residents (children and adults) were evaluated as
potential receptors in the quantitative risk assessment. Base workers were considered for current and
future conditions. Construction workers and onsite residents were evaluated for future conditions only
Although the potential for the base to be converted to residential land use is minimal, potential risks to
future onsite residents were quantified for purposes of completeness. Under the current and future land
use scenarios considered at Site 29, the exposure routes were incidental ingestion of soil and dermal
contact with soil.
The potential groundwater exposure route was considered for hypothetical future residents These
residents were assumed to be exposed by ingestion of groundwater, dermal contact with groundwater
and inhalation of volatiles emitted from water while showering. The potential inhalation of volatiles and
dust from soil was not considered because the site is relatively flat, and covered with asphalt or buildings
Volatile orgamcs are not COPCs at Site 29, and dust emissions would be minimal under current land use
conditions. It is assumed that good construction practices and moist soil at Site 29 (resulting from the
shallow water table) will minimize emissions of dust.
Exposure Assessment
, * that Were evaluated and tne'1" maximum exposure point concentrations are presented in
Table 2-5. Exposure point concentrations are used to determine potential human health risks.
Toxicity Assessment
The toxicity assessment characterizes the nature and magnitude of potential health effects associated with
human exposure to COPCs at a site. Quantitative risk estimates for each COPC and exposure pathways are
developed by integrating chemical-specific toxicity factors with estimated chemical intakes discussed in the
previous section.
Quantitative risk estimates are calculated using cancer slope factors (CSFs) for COPCs exhibiting
carcmogeniceffects and reference doses (RfDs) for COPCs exhibiting systemic (noncarcinogenic)effects A
summary of the RfDs and CSFs used in the baseline human health risk assessment is presented in
I 3D (6 fc~D.
CSFs and RfDs developed by USEPA are based on ingestion (oral) or inhalation routes of exposure rather
than dermal contact. Therefore, these values reflect administered doses rather than absorbed doses
USEPA guidance on assessment of dermal exposure (USEPA, 1992b) recommends that oral toxicity
factors used in dermal risk assessment be adjusted for gastrointestinal absorption efficiency, if such data
are available. The dermal RfDs and CSFs adjusted for gastrointestinal absorption are listed in Table 2-6
The dermal toxicity criteria are derived per the methodology presented in Appendix A of the Risk
Assessment Guidance for Superfund, Part A (USEPA. 1989). According to USEPA Region III policy the
dermal contact exposure pathways is not evaluated quantitatively for PAHs. Therefore, potential risks from
dermal contact exposure to benzo(a)pyrene in soil are not quantified in this risk assessment.
2-28
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TABLE 2-5
CHEMICALS OF POTENTIAL CONCERN AND EXPOSURE POINT CONCENTRATIONS'1'
SITE 29, BATTERY SERVICE AREA
NSWCDL, DAHLGREN, VIRGINIA
On
Chemical
games
Exposure Point
Concentration'1'
0.113 (ND)'2'
2.62 (2.62)12'
0.0749 (0.0734)'2'
1.57 (0.556)(2>
1 Maximum concentrations are used as exposure point concentrations for RME and CTE in soil and
groundwater because the post-removal soil and field investigation groundwater databases contain
less than 10 samples.
2 Values in parentheses are maximum concentrations from filtered samples.
ND = Not Detected
2-29
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TABLE 2-6
CJ
o
DOSE-RESPONSE PARAMETERS
SITE 29: BATTERY SERVICE AREA
NSWCDL, DAHLGREN, VIRGINIA
8
9
10
Chemical
Benzene
Benzo(a)pyrene
Aluminum
Arsenic
Chromium VI (hexavalent)
Iron
Lead
Manganese -water
Nickel
Zinc
RfD Oral11'
(mg/kg-day)
3E-3<"
NA">
1E+0">
3E-4
3E-3
oc 4(3)
NA®
2E-2")
2E-2
3E-1
RfD
Inhalation'"
(mg/kg-day)
1.7E-315'
NA«
1E-3<«
NA°>
3E-5
NA1 '
HA®
1.43E-5
NA®
NA«
CSF Oral'"
(kg-day/kg)
2.9E-2
7.3E+0
NA<»
1.5E+0
NA®
NA«
NA»
NAP)
NA«
NA«>
CSF
Inhalation'"
(kg-day/mg)
2.9E-2
3.1 E+0
NAW
1.51E+1
4.1E+1'4'
NA")
NA«
NAO)
NA
NA«'
0.05
0.95<5'
0.01'6'
NA^
MAO
0.03'"
0.04'"
0.5<10>
RfD Dermal
(mg/kg-day)
3E-3
NA'2>
5E-2
2.85E-4
3E-5
3E-1
NA">
6E-4
8E-4
1.5E-1
CSF Dermal
(kg-day/mg)
NA'«
NA'2)
^^— fc^-^— »^— ™— .
NA'»
1.58E+0
., .—
NAm
NA®
NA">
NA'J»
NA«>
NA«»
Weight of
Evidence
B2
82
NAW
A - Inhalation
1 A
NA">
B2
D
D
D
USEPA, 1999a (IRIS), unless otherwise noted.
NA - Not available/applicable.
USEPA-NCEA provisional value, 1998a
HEAST, 1997b.
ATSDR, 1991.
ATSDR, 1993.
^
USEPA, 1984
ATSDR, 1993
Elinder, 1986
USEPA's Weight of Evidence Classifications:
A1 Known human carcinogen.
B1 Probable human carcinogen; limited human data are available
sufficient evklence in animais
Not classifiable as to human carcinogenieity.
-------
Chromium Toxicity
Tfnt±h * 3 S?PC '" subsurface soil at Site 29 Analytical results for this chemical are
H t chromium. Chrom.um may be present in different oxidation states. The hexavalent
wh(ch ,s a less common state of chromium in environmental mixtures, is the most toxic form of
f^*** *** performed to distinguish among the specific chromium oxidation
^purposes of risk assessment, it is assumed conservatively that chromium is
Lead Toxicity
The equations and methodology used to evaluate other COPCs cannot be used to evaluate exposure to
aUSe ?™ f S6nce °f published dose-resPonse parameters for this constituent. Lead was
as a COPC for groundwater because the maximum detected concentration of lead 1 13 ng/L in
** (S°WA) Action Level
the USEPA lntegrated Exposure Uptake Biokinetic
to n t n , ' ?94a) f°r 6XpOSUre to sma" children- This model evaluates exposure
to lead in water and/or soil and is designed to estimate blood lead levels based on either default or site-
specific input values. The evaluation of lead is discussed below.
The toxicity profiles for the COPCs are presented in Appendix C.
Risk Characterization
Excess lifetime cancer risks are determined by multiplying the intake level and the cancer slope factor
These risks are probabilities that are generally expressed in scientific notation (e g ixlQ-6) An excess
hfetime cancer risk of 1 x 10* indicates that, as a plausible upper bound, an individual has a one in one
milhon 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 (i.e water air
or soil) is expressed as the hazard quotient (HQ) (or the ratio of the estimated intake derived from the
contaminant concentration in a given medium to the contaminant's RfD). By adding the HQs for all
contaminants within a medium or across all media to which a given population may reasonably be
exposed, the 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.
Base Worker. The cumulative noncancer His for ingestion of and dermal contact with soils for Site 29
under mdustnal land use conditions are less than one, which indicates that are no significant hazards are
associated with soils at Site 29.
The cumulative ingestion and dermal contact cancer risk is 2.8x10*. under a RME scenario Although the
incremental cancer nsk for the base worker slightly exceeded 1x10* it is within USEPA's target risk ranqe
of 1x10 to 1x10.
Construction Worker. The cumulative noncancer His for ingestion of and dermal contact with soils for
Site 29 under industrial land use conditions are less than one, which indicates that no significant hazards
are associated with soils at Site 29.
i
The cumulative ingestion and dermal contact cancer risk is 6.3x1 0'7, under a RME scenario which is less
than USEPA's target risk range of 1 x1 0" to 1 x1 0"6.
2-31
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Future Resident. The cumulative noncancer His for ingestion of and dermal contact with soils for Site 29
under hypothetical residential land use conditions are less than one, which indicates that no significant
hazards are associated with soils at Site 29.
The total residential incremental lifetime cancer risk based on cumulative ingestion and dermal contact
with soils is 7.8x1 0/6, under a RME scenario, which is within USEPA's target risk range of 1x10"* to
The cumulative noncancer His for exposure to groundwater for Site 29 under hypothetical residential land
use conditions are 16.5 for the RME. The HI for the RME exceeds one primarily as a result of the
ingestion of aluminum, arsenic, iron, and manganese in groundwater. The RfDs for aluminum and iron are
not based on any health effects but rather on recommended daily allowances for human nutrition.
Therefore, the risks for aluminum and iron are overstated. USEPA's risk assessment guidance allows the
Navy and USEPA to discount risk based on exceeding recommended maximum daily allowances for
nutrition. Additionally, evidence suggests that the arsenic, manganese and iron occur naturally in the
ground water at Site 29. The Superfund law forbids the Navy and USEPA from taking remedial action in
response to the release of "a naturally occurring substance in its unaltered form, or altered solely through
naturally occurring processes or phenomena, from a location where it is naturally found." 42 U.S.C. §
9604(a)(3). Accordingly, USEPA's risk assessment guidance permits EPA to discount risks that are
caused by naturally occurring conditions. A significant portion of the HI for ground water is due to iron,
manganese and arsenic. Background samples of ground water at NWSDL— i.e., ground water samples
designed to measure naturally occurring concentrations of substances — show that arsenic occurs
naturally in filtered ground water at concentrations ranging from 0-8 parts per billion (ppb), with average
background concentrations of 2-4 ppb. Arsenic was detected at 2.9 ppb in filtered ground water samples
taken from site 29, which is within the average background concentration range. Thus, it appears that
arsenic in ground water is due to conditions that occur naturally at NWSDL. Iron and manganese
concentrations are also within the range of background and appear to be naturally occuring conditions. In
these circumstances, USEPA and the Navy are permitted to discount risk due to iron, manganese and
arsenic in ground water. If aluminum, arsenic, iron, and manganese are eliminated as COPCs, the HI
calculated for the hypothetical resident is less than one. A HI of less than one indicates that there are no
significant hazards.
According to the risk assessment, a person who lived at the site for their entire life would face an
increased risk, equivalent to 14 chances in 100,000 (1.4 x 1Q-4), of developing cancer because she drank
unfiltered ground water. This risk is very slightly above the upper boundary of USEPA's acceptable risk
range, 1 x 10"4. USEPA risk assessment guidance, however, states that "The upper boundary of the risk
range is not a discrete line at 1 x 10"4 .... A specific risk estimate around 10"* may be considered
acceptable if justified based on site-specific conditions." Role of the Baseline Risk Assessment in
Superfund Remedy Selection Decisions at pg. 2, EPA Office of Solid Waste and Emergency Response
(OSWER) Directive 9355.0-30 (April 22, 1 991 ).
After considering the circumstances of Site 29, the Navy, USEPA and VADEQ have concluded that the
incremental cancer risk associated with drinking ground water is within acceptable limits. There are at
least two reasons for this conclusion. First, the element arsenic is by far the greatest contributor to the
incremental cancer risk associated with drinking ground water at Site 29. As noted above, however,
evidence suggests that the arsenic concentrations in ground water at Site 29 are due to naturally
occurring conditions. In these circumstances, USEPA and the Navy are permitted to discount risk due to
arsenic in ground water. When this is done, the incremental cancer risk attributable to drinking ground
water at Site 29 is within acceptable limits.
Second, the 1.4 x 10"* figure is based on the assumption that an adult resident would drink unfiltered
ground water for a lifetime. This is unlikely due to the naturally poor quality of groundwater, and some
filtration would be necessary. The calculated incremental cancer risk for filtered water at Site 29 is 8.8 x
10-s, which is within USEPA's acceptable risk range.
2-32
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Exposure to lead in groundwater (and soil) was evaluated using unfiltered groundwater concentrations
and maximum soil concentrations, respectively. Because of the absence of published dose-response
parameters for lead, the exposure and potential risks associated with lead are addressed through the use
of the USEPA Integrated Exposure Uptake Biokinetic (IEUBK) Model for the child 0-7years old. Based on
this model, the calculated risk was just equal to the established level of "concern" (10 ug/dL). However
risk due to lead is overstated based on the following factors:
• Maximum lead soil and groundwater concentrations were used in the IEUBK Model rather
than average concentrations. If average concentrations were used, the blood lead level
would be significantly lower.
• Unfiltered metals concentrations were evaluated in the risk assessment. Lead was not
detected in filtered samples collected during the field investigation, indicating turbidity
(suspended particulates) is influencing the metal concentrations reported for the unfiltered
samples. An analysis based on filtered samples would not include lead in groundwater
and the risk would be correspondingly reduced.
Uncertainty Analysis
The following sources of uncertainty are specific to post-remedial conditions at Site 29:
• Because less than 10 subsurface soil and groundwater samples are available in the post-
removal data sets for Site 29, the maximum reported concentrations were used as the
exposure point concentrations. The total risk estimates may be overestimated as a result
of the evaluation of maximum concentrations for all COPCs.
• The arsenic concentrations in groundwater reflect background (or upgradient) conditions
(i.e., upgradient and downgradient concentrations are similar). If arsenic was eliminated
as a COPC for groundwater, then the total carcinogenic risk estimate for the hypothetical
future resident exposed to soils and groundwater would fall within USEPA's target risk
range.
• The RfDs for iron and aluminum are not based on any health effects but rather on
recommended daily allowances for human nutrition. Consequently, some USEPA regions
(e.g., USEPA Region I) suggest that quantitative risk assessments not be performed for
aluminum and iron. If these constituents are eliminated as COPCs for groundwater, the
HI for the hypothetical future child and adult residents would be substantially reduced.
Summary and Conclusions
The following items summarize the results of a human health risk assessment conducted based on the
post-removal action soil and groundwater databases for Site 29:
1 His calculated for base workers who are exposed to soil do not exceed one indicating that
adverse health effects are not anticipated under the conditions established in the
exposure assessment. Cancer risk estimates developed for this receptor are 2.8 X 10*
and 5.0 X1Q-7 for the RME and Central Tendency Exposure (CTE) case, respectively.
Arsenic is the primary risk driver. However, arsenic concentrations appear to only
marginally exceed background. The arsenic concentrations in the Site 29 soils range
from 2.38 mg/kg to 7.64 mg/kg (average concentration was 4.2 mg/kg). The maximum
arsenic concentration in the background soil data set was 3.3 mg/kg.
2-33
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2. His calculated for the construction worker exposed to subsurface soil are less than one.
Consequently, adverse noncarcinogenic health effects are not anticipated for this
receptor. Cancer risk estimates for the construction worker do not exceed 1x10*.
3. A hypothetical future resident was evaluated for purposes of completeness. The His
calculated assuming exposure to subsurface soil are less than one. The cancer risk
estimates developed assuming exposure to soils for the RME and CTE cases (2.2x10's
and 2.2x1 0* respectively) are within USEPA's target risk range of 1x10-* to 1x10*. The
primary risk driver is arsenic. However, arsenic concentrations in the Site 29 soils are
marginally greater than background.
4. His were also developed for a hypothetical future resident using the groundwater as a
domestic water supply. The HI for the RME resident exposed to COPCs in groundwater
was 16.5. The primary risk drivers were aluminum, arsenic, manganese, and iron.
However, concentrations of arsenic, iron, and manganese appear to be naturally
occurring. The RfDs for aluminum and iron are not based on any health effects but rather
on recommended daily allowances for human nutrition. The manganese concentration
reported for the monitoring well located at the source area is less than the RBC for tap
water and is less than the concentration reported for a well located downgradient of the
source area. If aluminum, arsenic, iron, and manganese are eliminated as COPCs, the HI
calculated for the hypothetical resident using the groundwater is less than 1.0. A HI less
than 1.0 indicates that there are so significant hazards.
5. Cancer risk estimates developed for the hypothetical future resident using groundwater
were 1.4x10"* for the RME. However, arsenic, the major carcinogenic COPC in
groundwater, was detected at concentrations that appear to be naturally occurring.
6. The COPC concentrations reported for the Site 29 monitoring wells do not exceed current
Federal Safe Drinking Water Act (SDWA) primary (health-based) MCLs. Secondary
(aesthetic-based) standards for aluminum, iron, and manganese are exceeded.
Additionally, the maximum lead concentration in an unfiltered groundwater sample
exceeds the current SDWA Action Level for lead in drinking water. However, lead
concentrations in filtered groundwater samples do not exceed the current SDWA Action
Level for lead in drinking water, suggesting that turbidity is influencing lead concentrations
in the unfiltered sample. Lead concentrations reported for the unfiltered sample collected
from the upgradient monitoring well also exceed the SDWA Action Level. Lead is not a
pervasive contaminant in soils at Site 29.
The cancer risk estimates for the human receptors evaluated are within or less than USEPA's target risk
range of 1 X 10"* to 1 X 10"6 and reflect, in part, background or naturally occurring conditions for the site.
The His calculated for receptor exposure to soil are less than one indicating that adverse noncarcinogenic
health effects are not anticipated. The analytical results do indicate that the groundwater quality in the
vicinity of the site may not be suitable for domestic purposes. For the metals that drive the risk estimates,
the pattern of contamination and the aforementioned studies regarding manganese suggest that Site 29 is
not the source of these metal concentrations. Consequently, site-specific actions may be ineffective in
improving water quality or protecting future potential users.
2-34
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SOILS
The Draft Final Rl for Site 29 indicated metals concentrations in soil were the only contaminant that
warranted remedial action. Subsequently, the neutralization pit and adjacent soils were excavated and
disposed of offsite. Sampling data was collected to verify the removal action had achieved its objectives.
This data was re-evaluated in a revised risk assessment. The revised risk assessment for soil indicated
remaining risks are acceptable. It is recommended that no further action be taken for soils at Site 29.
GROUNDWATER
The risk assessment for groundwater indicates risks are acceptable even though they are at the upper
end of the acceptable limit. Site 29 is not the source of the metals that are driving the risk. It is
recommended that no further action be taken for groundwater at Site 29 for the following reasons:
1. The pattern of groundwater contamination indicates that the Site 29 neutralization pit is not a
source of the contaminants.
2. Arsenic concentrations in downgradient wells (filtered and unfiltered) were slightly less than
concentrations detected in the upgradient well (filtered and unfiltered). Arsenic
concentrations appear to be naturally occurring.
3. Iron concentrations in downgradient wells were similar to or less than concentrations
detected in the upgradient well. Based on this, downgradient iron concentrations are not
considered significantly different from background concentrations. Furthermore, the iron
concentrations downgradient of Site 29 are considerably less than the maximum basewide
concentration reported by the USGS.
4. Lead concentrations detected in the upgradient well and in GW29-2, which is located at the
source area, exceeded the SOWA Action Level (15 ng/L) in unfiltered samples. However,
lead was not detected in filtered groundwater samples from either well and results of the
IEUBK Model suggest that no action is necessary to protect human health.
5. Manganese concentrations detected in GW29-2 (141 ng/l), which is located at the source
area, were less than the upgradient concentration (272 ng/l). It should be noted the
downgradient concentration (2,600 ng/l) were higher than the site-specific background
concentration. However, all Site 29 manganese values are well below the maximum
basewide concentration reported by USGS (7,000 ng/l).
The pattern of metals detected in shallow groundwater at Site 29 indicates the metals concentrations are
attributable to naturally occurring conditions and not attributable to Site 29. Based on this, the selected
remedy for Site 29 is no further action.
2.14 DOCUMENTATION OF SIGNIFICANT CHANGES
The selected remedy is the same alternative identified as the recommended alternative in the Proposed
Remedial Action Plan and that was presented to the public at the public meeting held July 28,1999.
There were no significant changes to the recommended remedial action alternative in the Proposed Plan.
2-35
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2-36
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3.0 RESPONSIVENESS SUMMARY
No written comments, concerns, or questions were received by the Navy, USEPA, or the Commonwealth
of Virginia during the public comment period from July 21, 1999 to August 19, 1999. A public meeting was
held on July 28, 1999 to present the Proposed Plan for Site 19 and Site 29 soils and groundwater and to
answer any questions on the Proposed Plan and on the documents in the information repositories. A 30-
minute presentation was provided during which informal questions were addressed.
A summary of the questions (and responses) that were asked at the public meeting is provided in
Appendix B.
3.1 BACKGROUND ON COMMUNITY INVOLVEMENT
The Navy and NSWCDL have had a comprehensive public involvement program for several years.
Starting in 1993, a Technical Review Committee (TRC) met, on average, twice a year to discuss issues
related to investigative activities at NSWCDL. The TRC was composed 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 eight to ten
community representatives joined. The RAB is co-chaired by a community member and has held
meetings approximately every 4 to 6 months. The RI/FS and the Proposed Plan for Site 19 soils and
Site 29 soils and groundwater were both discussed at the RAB meetings.
Community relations activities for the final selected remedy include:
• The documents concerning the investigation and analysis at Site 19 and 29, as well as a
copy of the Proposed Plan, were placed in the information repository at the NSWCDL
General Library and the Smoot Memorial Library.
• Newspaper announcements on the availability of the documents and the public comment
period/meeting date was placed in The Journal on July 14, 1999 and the Freelance Star
newspaper on July 19,1999.
• The Navy established a 30-day public comment period starting July 21, 1999 and ending
August 19, 1999 to present the Proposed Remedial Action Plan. No written comments
were received during the 30-day public comment period.
• A Public Meeting was held July 28, 1999 to answer any questions concerning the Site 19
and 29 Proposed Plan. Approximately 10 people, including Federal, state, and local
government representatives attended the meeting.
3-1
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3-2
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APPENDIX A
VIRGINIA CONCURRENCE LETTER
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SEP,-23'99fT}JU) 13:17 DEQ TEL:8046984234 P.003
COMMONWEALTH of VIRQINIA
DEPARTMENT OF ENVIRONMENTAL QUALITY
Governor S*r««f***wfi29 Butt Miin Sntei, Riciunood. Virginia 23219
Mailing aUna: P.O. Box 10009. Richmond, Vfaginim 23240 (104) 60MOOO
Joh«P-Wcxxfcy J, Ftt(W4)69W50fl TDD (104) 69*^021 1-IOO.S9M4C
ScacttyorNaunlRi^urcci taQ»rf/www.dcq.«ie.vttts
September 23,1999
Mr. Abraham Ferdas, Division Director
Hazardous Site Cle;inup Division (3HSOO)
U.S. Environmental Protection Agency, Region m
1650 Arch Street
Philadelphia, PA 19103-2029
Re: Record of Decision for Site 19 (Soil) and Site 29, NSWC Dahlgren, Virginia
Dear Mr. Ferdas:
The Virginia Department of Environmental Quality staff has reviewed the Record
of Decision ("ROD'1) for Site 19 - Transformer Draining Area (Soils), and Site 29 -
Battery Service Area (Soils and Groundwater), at the Naval Surface Warfare Center,
Dahlgren, Virginia. On behalf of the Commonwealth of Virginia, we concur with the
selected remedial alternatives as outlined in the ROD dated September 1999.
Should you have any questions concerning this letter, please feel free to contact
Dave Gillispie at (804) 698-4209.
Very truly yours,
Erica S. Dameron
Director, Office of Remediation Programs
cc: Ryan Mayer, ChesDiv
Ann Swope. NSWC Dahlgren
Bruce Beacli, EPA Region m
Hassan Vakili,VDEQ
Durwood Willis, VDEQ
Dave Gillispie, VDEQ
An Agency of the Natural Resources Secretariat
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APPENDIX B
PUBLIC COMMENTS
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APPENDIX B
SUMMARY OF QUESTIONS FROM 28 JULY 99 PUBLIC MEETING
Site 19
Have we found any contaminants in the groundwater?
Polychlorinated Biphenyl's were not found in groundwater sampling; however, groundwater investigations
have indicated several metals which have exceeded U.S. EPA Region III screening criteria (i.e..
aluminum, arsenic, barium, beryllium and vanadium), and maximum contaminant levels (MCLs) for
beryllium and lead. Organic compounds, specifically phthalates were detected, however, none were
above MCL's and one (dibenz(a.h)anthracene) was above a screening level. The final assessment for
groundwater will be done in conjunction with a nearby adjacent site (Site 40) in the near future.
Where is Site 19 relative to other buildings?
Site 19 is located in the south-central portion of the NSWCDL property, approximately 150 feet east of
Caskey Road. Building 120B Defense Reutilization and Marketing Office (DRMO) lot is located nearby
on the northeast portion of the site. The outside storage area of the DRMO lot is designated as Site 40.
Site 40 is planned for investigation as outlined in the Site Management Plan. A temporary clinic is located
southeast of the site approximately 200 feet away.
Site 29
Has there been any indications of heavy metal contamination at this site?
Soil samples collected indicated the following contaminants; antimony, arsenic, iron, lead, mercury and
total petroleum hydrocarbons. These contaminants were excavated during a Removal Action conducted
in 1997. These contaminants were removed to the target cleanup levels, except for arsenic. It was
determined that remaining arsenic levels were safe and similar to background levels.
Where were excavated soils taken during the Removal Action of the site?
Soil from Site 29 was excavated and transported to the permitted King & Queen Landfill located in Little
Plymouth, Virginia for disposal.
B-1
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08/20/99
07:07
033 2339
SAFETY * ENV C28 -»-»-» EFA Cbee Code 18
12)002
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NAVAL SEA SYSTEMS COMMAND
NAVAL SURFACE WARFARE CENTER
DAHLGREN DIVISION
PUBLIC MEETING
THURSDAY, JULY 28, 1999, 7:00 P.M.
KING GEORGE COUNTY COURTHOUSE
KING GEORGE, VIRGINIA
PROPOSED REMEDIAL ACTION PLAN
Site 19, Transformer Draining Area
Site 29, Battery Service Area
Site 25, Pesticide Rinse Area
USEPA Reg:.on III
Hazardous Site Cleanup Division
Federal Facilities Section
Mr. Bruce Beach
1650 Arch.Street. Philadelphia, Pennsylvania 18107
Virginia Department of Environmental Quality
Mr. David Gillispie
629 East Main Street. Richmond. Virginia 23219
Public Affairs Office
Commander, Naval Surface Warfare Center
Ms- Jennifer Wilkins
17320 Dahlgren Road, Mail Code CD06 Dahlgren, Virginia 22448
Reported by: Lola Gail Serrett
FRANCES K. HALEY & ASSOCIATES, Court Reporters
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July 28, :.999:
MS. SWOPE: Good evening. everyone.
I want to welcome you tonight to our public meeting
that we're having for the public comment period
which announces proposed remedial actions for three
sites at the Naval Surface Warfare Center, that the
Navy, the Commonwealth of Virginia and the
Environmental Protection Agency have choaen as the
proposed plans that we would like to remediate these
sites with. We're going to present a brief synopsis
of that action to you tonight. You have -- some of
.you have seen copies of the documents. They went
down to the RAB members. They're also in the Smoot
Library and the Dahlgren Library and we have copies
on base, if you'd like to see it. The information
is on the back on how to contact us with more
questions. Yeah, they're in the back o£ the room.
Also, I want to introduce to
Dave Misenhimer. He works for Tetratech, NUS. He's
going to do the presentations tonight. He is
probably the chief member of our contracting team
FRANCES K. HALEY & ASSOCIATES, Court Reporters
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that does all our investigations for us and most of
the design work, all of his Tetratech teams. So,
Dave, I'll let you take it away.
MR. MXSENHIMER: Okay.
MS. SWQPE: Oh, one more thing. I'm
sorry. Just so you know, this is -- we have a court
reporter here. We're recording everything tonighfc.
Your comments are welcome, but we want to document
those comments BO we properly respond to your
comments since this is a public comment period. So.
feel free to interject whenever you have a question,
concern or need clarification.
MR. MISENHIMER: Thank you. Okay.
This machine is just beginning to warm up. But as
Ann just said, there's two documents that are in the
back of the room there. The first one deals with
two sites; Site 19 and Site 29. And I'm going to go
through Site 19 first, followed by Site 29. The
second document deals with Site 25 entirely.
MS. SWOPE: That'B reversed.
MR. MISBNHIMER: I don't know what
PRANCES K. HALEY & ASSOCIATES, Court Reporters
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happened here. Let•a try this again.
MS. SWOPEi It was working
beautifully, too.
MR. MISENHIMER: Yeah, it was
working.
MR. FUSCAXiDO: You got a discount
because it's upside down.
MS. SWOPS: Exactly. You can ahow
the location on the map.
MR. MISENHIMER: Yeah. The three
sites that we're dealing with -- Site 19, is located
right here. This is main aide, here's 301. the
Potomac River, Upper Maohodoc Creek. So, Site 19 is
kind of on the south aide of main side. Site 29 is
a little further south, over here. And Site 25 is
located on the drain swell here that feeds into
Upper Machodoc Creek.
Now. it's working. Okay. I
don't know what happened. Anyway, so we're going to
staz-t out with Site 29 -- Site 19. And both, Site
19 and 29, are grouped together because these are
FRANCES K. HALEY £ ASSOCIATES, Court Reporters
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two sites where we did some remedial action in the
past and we're proposing that no further action be
taken upon those two sites; whereas. Site 25. we
have not done any remedial action to date and we are
proposing to do some remedial action. That's what
we'll be focusing on today.
So. at Site 19, this was a
transformer draining area. Transformers were
drained on the ground and transformer oil typically,
in the days when thie occurred, had PCB oil in the
transformers. PCBs were found to be a human health
risk and they were present in the soil where the
transformers were drained. So, in 1994, the PCB
contaminated soil was removed.
MS. SWOPE; This site is right south
of the sea plane hangar.
MR. MISENHIMER: Here's an aerial
photo of the site. This area in red is Site 19.
It's adjacent to Site 40, which is another site that
is currently under investigation in the Installation
Restoration Program at Dmhlgircn. And there's some
PRANCES K. HALEY & ASSOCIATES, Court Reporters
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concrete pads, here, where they stored the
transformers and this is generally the area where
transformer oil was dumped. This area, in general,
is fairly flat, so anything that was dumped out here
didn't really move too far. Groundwater generally
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flows in this direction, to the east. And
approximately a thousand gallons of transformer oil
were dumped there in th« past -- drained there in
the past.
Here's a site photo. In fact,
the concrete pad I pointed out to you is right here.
Here's a monitoring well. The area where
transformer oil was drained ie over in this area and
this is the area where, in 1994, the contaminated
soil was removed. Th« area that was -- where the
removal occurred was about twenty-five feet by
seventy feet, in length and width. And the soil was
removed down to a depth of approximately two feet.
So, there were about a hundred and seventy-seven
cubic yards of soil that were removed, in total,
from the site. The target cleanup level for the PCB
FRANCES K. HMJSY & ASSOCIATES, Court Reporters
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contaminated soil was a residential land use value
that US EPA has established, which is one part per
million. And cleanup was sueeeaaful in getting all
the contaminated soil out of there and verification
sampling verified that we did reach that level.
MR. FUSCALDO; I mean, have the
monitoring wells picked up anything?
MR. MISENHIMER: No, there's
really -- well, one thing I should -- this is what I
want to point out here. In terras of groundwater,
because we have Site 40 very close by and that site
is being investigated. we decided to address
groundwater with that adjacent site when we look at
that site. It didn't make a lot of sense to try and
break one area up from the other. So --
MS. SWOPE: (interjecting) But we
have not found PCBs in the groundwater.
MR. MISENHIMBR: Right.
MR. FXJSCALDO-. The clinic is there
someplace now, isn't it? The temporary clinic.
MS. SWOPB: Yes.
FRANCES K. HALEY & ASSOCIATES, Court Reporters
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MR. FUSCAiDO: Where is that on
this --in relation to --
MS. SWOPE: You go back to the --
hang on. I'll show him. Qo back to the aerial
photo, it is right -- right in here.
MR. FCSCALDO: Okay. All right.
CAPTAIN MAHAFFEY: That's a new
building.
MS, SWOPS: Yeah.
MR. MISENHIMER: So. what we're
proposing today ia that the removal or cleanup that
occurred in 1994 wae sufficient and that no further
action is required for the soils in that area, and
.the groundwater, again, ae I said, be evaluated with
an adjacent site. And that's pretty much all I waa
going to say about Site 19. Are there any
quostione?
MR. FUSCALDO: And Site 40. what was
that again?
MS. SWOPS: That's a storage lot,
scrap metal.
PRANCES K. HALEY & ASSOCIATES, Court Reporters
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MR. MISENHIMER: Now, let's see if I
can pull it up. Okay. Site 29 is the second site
we want to talk about today. This is an area where
an unlined neutralization pit received battery acid
from an area about where batteries were drained.
And in 1995, our remedial investigation suggested
that there were human health risks, potential risks
with heavy metals in the soils, so in 1997, the
neutralization pit and all the soil that surrounded
that neutralization pit was removed. Here's an
aerial photo. This area in red, within this area
here is where the neutralization pit was located and
it's —
MS. SWOPfi: (interjecting) It's the
corner between the heavy duty shop and the battery
shop, behind it, toward the community house.
MR. MISENHIMER: And the surrounding
soil, which was removed. Just south of the site is
a cooling pond. The cooling pond, which is also
known as Site 55, is another installation
restoration site which is currently under investi-
FRANCES K. HALEY & ASSOCIATES, Court Reporters
10500 Wakeman Drive, Suite 300, Frederieksburg, VA 22407
PHONE; (540)896-1527 FAX; (540)898-6154
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gation. These buildings are in the transportation
area and there's a lot of activity that goes on
around there related to transportation, and public
works.
Here's a site photo. The area
that we have highlighted in red is essentially this
area in here. The neutralization pit is under-
ground. It was covered over some years ago and
covered with asphalt paving and -- so. we had to dig
that up to find the neutralization put and remove
any contaminated soil that surrounded it.
MR. FUSCAUJO: Now, I remember
this -- I don't know how many -- how many meetings
ago it was that -- when this thing waa detailed.
MS. SWOPE: When we did the work?
MR. FUSCALDO: And I'm just kind of
wondering how -- how that's turned out, you know,
has there been any other indications of heavy metal
contamination in there?
MR. MISENHIMER: Well, what we did
was the area that was excavated here was an area
FRANCES K. HALEY fc ASSOCIATES, Court Reporters
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that encompassed about twenty-two feet by about
thirty-eight feet. Me went down seven feet. Before
we got started, we had some preliminary goals in
terms of what kinds of levels were acceptable for
metals in the soils. So, as we went along, we
sampled the soil. If we weren't meeting our goal,
we dug some more out until we got. to the point where
we felt we were okay. After that was completed and
the sampling data came back, then we looked at the
human health risks. We'd run the numbers that you
typically do to evaluate human health risks and
based on that analysis, it was determined that the
soil was fine, as well as the groundwater on this
MS. SWOPE: When we removed that, we
removed a couple of oil separators that were old, an
old oil tank.
MR. MISENHIMERs Right, right. Yes.
MS. SWOPE: There was a lot of things
in th« ar*a, so w« got rid of it all together.
MR. FOSCALBO: I remember it was a
FFANCES K. HALEY & ASSOCIATES, Court Reporters
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real bad eite.
MS. SWOPE: Right.
MR. FUSCALDO: Like meet of that old
stuff is.
MR. MISENHIMER: Okay. So, the
contaminants that we were concerned about are listed
up here; antimony, arsenic, iron, lead and mercury.
So, as I said, when the soil was removed, we took
samples and these were the things that we were
checking- on. And then, when we did the risk
assessment, we did it baaed on these contaminants.
So, in summary, we feel that
there's no need for any further action on the soils
at Site 29 and that, based on our evaluation of
.groundwater, there's no need for any action with
groundwater. The groundwater is fine and we believe
that we're done with this site, essentially. Yes?
MS. VAN DB WBERT: you keep saying
the soils were removed. Where are they taken to?
MR. MISENHIMER: Oh, okay.
MS. VAN DE WEERT-. Landfills?
FRANCES K. HALEY & ASSOCIATES, Court Reporters
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MR. MISEKHIMER: Yea. They're taken
off-site to a landfill.
MS. SWOPE; Actually --
MR. FUSCALDO: (interjecting) Well.
it's an incinerator, isn't it?
MS. SWOPE; The PCB -- the PCS
soil -- this soil went to a. cement kiln, brick kiln,
I think. And then, the PCB soil went to one of very
few PCB facilities that either landfill it or bum
it, depending on the concentration of PCBs. And
they verify that when they get it there. There are
very few that will accept that. It went out west by
train.
MR- FUSCALDO: It just doesn't get
moved sonwwher* «lsa to ba somebody else's problem?
MR. MISENHIMER: No.
MS. SWOPE: Right. But the primary
thing here were -- essentially, any time you've got
petroleum type products, it ends up being burned in
a brick kiln a lot of times, BO you get some
valuable use out of it.
FRANCES K. HALEY & ASSOCIATES, Court Reporters
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MR. MISENHIMER: Any more questions?
Okay. Our next site is Site 25, known as the
pesticide rinse area. And this ie an area where
pesticide containers were rinsed outside and the
containers were then -- whatever was left waa
spilled on the ground. And also, inside a building,
there was a slop sink where containers were rinsed
and thie slop sink drained into a freneh drain. Our
remedial investigation suggested there were human
health and ecological concerns from pesticides and
heavy metals in the soil and in the sediment.
This is an aerial photo and it
showB you building 134, right here. This is the
building where the slop sink was located and this is
the freneh drain, so material would drain out here
and infiltrate into the ground. The other area
where the container* were rinsed was out in this
area, here, and whatever was lefc in the container
was then dumped on the ground out here, So, in our
investigation, we were concerned about the freneh
drain and any movement of any of the contaminants.
FRANCES K. HALEY & ASSOCIATES, Court Reporters
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the pesticides that may be present there. And then,
this area, here, where we know things were dumped or.
the ground.
The other thing I guess 1 wanted
to point out on this slide is that this is a
drainage through here . It' a kind of an intermittent
drainage way and it is -- a good portion of this has
been delineated as a wetland area.
Upgrade, here, is the cooling
pond, just to relate back to Site 29. Site 25 is
somewhere over in this direction. The cooling ponds
are over here. And this is Site 25. So,
ultimately, any overland flow drains down in this
direction and into the Upper Machodoc Creek.
This is a site photo. Looking
towards the Potomac River and Upper Machodoc Creek
over in this direction. This is part of the wetland
area in here and this is a monitoring well.
Now, this diagram shows what the
preferred alternative is and it may be difficult to
see this in the back there, but on the handout, this
FRANCES K. HALEY & ASSOCIATES, Court Reporters
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little handout here, it might be easier to follow.
There's a green, line here that outlines the wetland
area and then, this solid line, here, outlines the
area where we're proposing to excavate the
contaminated soil and haul that off-site for
disposal at a landfill.
There are also some hot spot
areas identified. Here's one. Here's another one.
And then, the french drain area, which would also be
excavated and hauled off-site for disposal. In this
case, the material that would be hauled off would go
to landfill and Used as a daily cover at a landfill.
The levels of contaminants are not that high that it
would require any creatment prior to going to a
landfill.
After this area, here, is
excavated, we're talking about going down to a depth
of about two feet. In some hot spot areas
identified here, we might be going dawn as far as
four -- four or fiv« f««t. This area would then be
regradad to -- back to the •scisting area and the
FRANCES X. HALEY & ASSOCIATES, Court Reporters
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wetland area would be reestablished.
So. the preferred alternative is
that we remove all the contaminated soil.
reestablish the wetland, we're going to send the
contaminated soil to an off-site landfill. And
because of this, we would have a situation where no
long term monitoring of the site would be necessary
because we're removing all the contaminated soil.
Any questions on Site 25?
MR. FUSCALDO: I guess r-- yeah, how
do you -- how do you determine that you removed all
the contaminated soil? That's a hard thing to do at
a site like that, isn't it?
MR. MISENHIMER: Okay. That's a good
question. Whenever we do any excavation like this,
part of the project is to verify what you have left
after you've taken this out, the soil that's left is
clean. And so. a verification sampling plan ia
prepared and then we go ahead and take samples. So.
as you're excavating this, we will typically grid
thia area off and then take camplee at different
FRANCES K. HALEY t ASSOCIATES, Court Reporters
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point* and based on, those sampling results, we'll
decide, okay, is it okay or do we need to remove
some more soil.
MR. FUSCALDO: How do you work that
site when it's so wet in there.
MS. SWOPB: We could it right now.
MR. FUSCALDO: Okay.
MR. MISENHIMBR: That's a good point.
MR. FUSCALDO: That gives me an
indication. Okay,
MR. MISENHIMER; But one of the
things that we take into consideration is really the
time of year in which we're trying to work. We'll
try to make sure it's during a dry period. You
know, there's no guarantees on that, as you well
know. But apparently --
MR. FUSCALDO: (interjecting) August
is supposed to be pretty wet.
MS. SWOPE: These are all proposed
that we would do the work next fiscal year, so it
will happen in 2000.
FRANCES K. HALEY & ASSOCIATES, Court Reporters
10500 Wakeman Drive, Suite 300, Predericksburg, VA 22407
PHONE: (540)898-1527 FAX: (540)698-6154
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MR. FUSCALDO: Okay. All right.
MS. SWOPE: And the other thing is
that when we remove that, we'd like to increase the
wetland capacity there and make it even more
beneficial aa wetland and not replace -- you know,
not have to haul in clean dirt, just regrade and
make it a better wetlands.
MR. FUSCALDO: Good idea. Good idea.
MR. MISENHIMER: Any other questions?
MS. SWOPE: Do we want to have a
formal comment period. You know, I'll take another
.minute for you to ask more questions that will be
recorded and after that, we'll cut off the recorder.
We have refreshments and you can ask us eome more
questions that you'd rather not be recorded.
MR. FUSCALDO: I'm personally
finished.
MS. SWOPE: Okay. Patty, do you have
any more questions?
MS. VAN DE WEERT: No.
PRANCES X. HALEY & ASSOCIATES, Court Reporters
10500 Wakeman Drive. Suite 300, Fredericksburg, VA 22407
PHONE: (540)898-1527 FAX: (540)898-6154
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MS. SWOPE: Anyone? Captain?
MR. MISENHIMER: One thing that I
guess should be mentioned is that the comment
started last Wednesday.
MS. SWOPE: It was announced in the
Free Lance.
MR. MISENHIMERt Right. And it goes
for thirty daya and the comment period ends
August --
MS. SWOPE: 19th.
MR. MISENHIMBR: August 19th.
MS. SWOPEs So, you are welcome to
submit written comments Co the locations on the back
anytime before August 19th. If you think of
something elBO or you pass the information to
someone who has questions, we welcome any questions
or comments. Anybody else? We'll officially close
the comment period then.
MEETING CONCLUDED AT 7:32 P.M.
FRANCES K. HALEY & ASSOCIATES, Court Reporters
10500 Wakeman Drive, Suite 300, Predericksburg, VA 22407
PHONE: (540)898-1527 PAX: (540)898-6154
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CERTIFICATE OP COURT REPORTER
I, Lola Gail Searrett, hereby certify that I was the
Court Reporter at the Public Meeting held at King George
Courthouse, King George, Virginia, on July 2S, 1999, at the
time of the meeting herein.
I further certify that the foregoing transcript is J
true and accurate record of the proceeding herein.
Given under my hand this 3lst day of July, 1399.
I OLA GXL SERRETT
/Court Reporter
PILE: PO'.'2899L.HRG
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
TOXICITY PROFILES
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APPENDIX C
TOXICITY PROFILES - DAHLGREN, SITE 19
ALUMINUM
Aluminum is not generally regarded as an industrial poison. Inhalation of finely divided powder has been
reported as a cause of pulmonary fibrosis. Aluminum in aerosols has been implicated in Alzheimer's
disease. As with other metals, the powder and dust are the most dangerous forms. Most hazardous
exposures to aluminum occur in refining and smelting processes. Aluminum dust is a respiratory and eye
irritant. The USEPA has published an oral RfD of 1.00 mg/kg/day (IRIS) and an inhalation reference dose
of 0.001 mg/kg/day (HEAST, 1997) for aluminum.
AROCLOR 1260
Hepatotoxicity is a prominent effect of PCBs, including Aroclor 1260, that has been well characterized.
Effects include hepatic microsomal enzyme induction, increased serum levels of liver-related enzymes
(indicative of hepatocellular damage), liver enlargement, lipid deposition, fibrosis, and necrosis.'
Chloracne and Immune function disorders have been observed in humans and several animal species
after PCB exposure. Reproductive and developmental effects, including low-birth weight, and decreased
gestational time, and decreased reproductive capacity, have been observed in human and animal
species.
Data are suggestive but not conclusive concerning the carcinogenicity of PCBs in humans.
Heptatocellular carcinomas in three strains of rats and two strains of mice have led the EPA to classify
PCBs as group 62, probable human carcinogen.
ARSENIC
The toxicity of inorganic arsenic (As) depends on its valence state (-3, +3, or +5), and also on the physical
and chemical properties of the compound in which it occurs. Trivalent (As+3) compounds are generally
more toxic than pentavalent (As+5) compounds, and the more water soluble compounds are usually more
toxic and more likely to have systemic effects than the less soluble compounds, which are. more likely to
cause chronic pulmonary effects if inhaled.
The Reference Dose for chronic oral exposures, 0.0003 mg/kg/day, is based on a NOAEL of 0.0008
mg/kg/day and a LOAEL of 0.014 mg/kg/day for hyperpigmentation, keratosis, and possible vascular
complications in a human population consuming arsenic-contaminated drinking water. Because of
uncertainties in the data, U.S. EPA states that "strong scientific arguments can be made for various
values within a factor of 2 or 3 of the currently recommended RfD value." The subchronic Reference
Dose is the same as the chronic RfD, 0.0003 mg/kg/day.
Epidemiological studies have revealed an association between arsenic concentrations in drinking water
and increased incidences of skin cancers (including squamous cell carcinomas and multiple basal cell
Carcinomas), as well as cancers of the liver, bladder, respiratory and gastrointestinal tracts. Occupational
exposure studies have shown a clear correlation between exposure to arsenic and lung cancer mortality.
U.S. EPA has placed inorganic arsenic in weight-of-evidence group A, human carcinogen.
CHROMIUM
*
In nature, chromium (III) predominates over chromium (VI). Little chromium (VI) exists in biological
materials, except shortly after exposure, because reduction to chromium (III) occurs rapidly. Chromium
(III) is considered a nutritionally essential trace element and is considerably less toxic than chromium (VI).
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Acute oral exposure of humans to high doses of chromium (VI) induced neurological effects Gl
hemorrhage and fluid loss, and kidney and liver effects. An NOAEL of 2.5 mg chromium (VI) /kg/day'in a
one-year drinking water study in rats and an uncertainty factor of 300 was the basis of a verified RfD of
0.003 mg/kg/day for chronic oral exposure. An NOAEL (No effects were observed in rats consuming 5%
chromium (lll)/kg/day in the diet for over two years) of 1,468 mg/kg-day for chromium (III) and an
uncertainty factor of 100 was the basis of the RfD of 1.5 mg/kg/day for chronic oral exposure.
Occupational (inhalation and dermal) exposure to chromium (III) compounds induced dermatitis. Similar
exposure to chromium (VI) induced ulcerative and allergic contact dermatitis, irritation of the upper
respiratory tract including ulceration of the mucosa and perforation of the nasal septum and possibly
kidney effects.
A target organ was not identified for chromium (III). The kidney appears to be the principal target organ
for repeated oral dosing with chromium (VI). Additional target organs for dermal and inhalation exposure
include the skin and respiratory tract.
IRON
No toxicity information available. The RfD for iron "(0.3 mg/kg/day is based on allowable intakes rather
than adverse effect levels.
MANGANESE
Manganese is an essential trace element in humans that can elicit a variety of serious toxic responses
upon prolonged exposure to elevated concentrations either orally or by inhalation. The central nervous
system is the primary target. Initial symptoms are headache, insomnia, disorientation, anxiety, lethargy,
and memory loss. These symptoms progress with continued exposure and eventually include motor
disturbances, tremors, and difficulty in walking, symptoms similar to those seen with Parkinsonis.m.
These motor difficulties are often irreversible.
Effects on reproduction (decreased fertility, impotence) have been observed in humans with inhalation
exposure and in animals with oral exposure at the same or similar doses that initiate the central nervous
system effects. An increased incidence of coughs, colds, dyspnea during exercise, bronchitis, and
altered lung ventilatory parameters have also been seen in humans and animals with inhalation exposure.
A chronic and subchronic RfD for drinking water has been calculated by EPA from a human no observed
adverse-effect level (NOAEL). The NOAEL was determined from an epidemiological study of human
populations exposed for a lifetime to manganese concentrations in drinking water ranging from 3.6-2300
pg/L A chronic and subchronic RfD for dietary exposure has been calculated by EPA from a human
NOAEL which was determined from a series of epidemiological studies. A reference concentration (RfC)
for chronic inhalation exposure was calculated from a human LOAEL for impairment of neurobehavioral
function from an epidemiological study.
VANADIUM
Vanadium is a metallic element that occurs in six oxidation states and numerous inorganic compounds.
Vanadium is used primarily as an alloying agent in steels and non-ferrous metals. Vanadium compounds
are also used as catalysts and in chemical, ceramic or specialty applications. Vanadium compounds are
poorly absorbed through the gastrointestinal system but slightly more readily absorbed through the lungs.
Absorbed vanadium is widely distributed in the body, but short-term localization occurs primarily in bone,
kidneys, and liver.
The toxicity of vanadium depends on' its physico-chemical state particularly on its valence state and
solubility. In animals,-acutely toxic oral doses cause vasoconstriction, congestion and fatty degeneration
of the liver, congestion and focal hemorrhages in the lungs and adrenal cortex. Minimal effects seen after
subchronic oral exposures to animals include diarrhea, altered renal function, and decreases in
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erythrocyte counts, hemogloblin, and hematocrit . In humans, intestinal cramps and diarrhea may occur
following subchronic oral exposures. the£e studies indicate that for subchronic and chronic oral
exposures the primary targets are the digestive system, kidneys, and blood.
The reference dose (RfD) for chronic oral exposures to vanadium is 0.007 mg/kg/day. Inhalation
exposures to vanadium and vanadium compounds result primarily in adverse effects to the respiratory
system. There is little evidence that vanadium or vanadium compounds are reproductive toxins or
teratogens. There is also no evidence that any vanadium compound is carcinogenic; however, very few
adequate studies are available for evaluation. Vanadium has not been classified as to carcinogenicity by
the U.S. EPA.
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TOXICITY PROFILES - DAHLGREN, SITE 29
ALUMINUM
Aluminum is not generally regarded as an industrial poison. Inhalation of finely divided powder has been
reported as a cause of pulmonary fibrosis. Aluminum in aerosols has been implicated in Alzheimer's
disease. As with other metals, the powder and dust are the most dangerous forms. Most hazardous
exposures to aluminum occur in refining and smelting processes. Aluminum dust is a respiratory and eye
n"S mltfJ /SLffX£.a.n °rf Rf° °f 10° m9/k9/day and an inhalation reference dose of
0.001 mg/kg/day (HEAST, 1997) for aluminum.
ARSENIC
The toxicity of inorganic arsenic (As) depends on its valence state (-3. +3, or +5), and also on the physical
and chemical properties of the compound in which it occurs. Trivalent (As+3) compounds are generally
more toxic than pentavalent (As+5) compounds, and the more water soluble compounds are usually more
toxic and more likely to have systemic effects than the less soluble compounds, which are more likely to
cause chronic pulmonary effects if inhaled.
The Reference Dose for chronic oral exposures, 0.0003 mg/kg/day, is based on a NOAEL of 0 0008
mg/kg/day and a LOAEL of 0.014 mg/kg/day for hyperpigmentation, keratosis, and possible vascular
complications in a human population consuming arsenic-contaminated drinking water Because of
uncertainties in the data, U.S. EPA states that "strong scientific arguments can be made for various
values within a factor of 2 or 3 of the currently recommended RfD value." The subchronic Reference
Dose is the same as the chronic RfD, 0.0003 mg/kg/day.
Epidemiological studies have revealed an association between arsenic concentrations in drinking water
and increased incidences of skin cancers (including squamous cell carcinomas and multiple basal cell
Carcinomas), as well as cancers of the liver, bladder, respiratory and gastrointestinal tracts. Occupational
f,XS°lUr,r! !tud'e,s have shown a clear conation between exposure to arsenic and lung cancer mortality
U.S. EPA has placed inorganic arsenic in weight-of-evidence group A, human carcinogen.
BENZENE
Benzene is absorbed via ingestion, inhalation, and skin application. Humans may absorb benzene vapors
through the skin as well as the lungs; of the total dose absorbed by the two routes, an estimated 22-36%
enters the body through the skin.
Limited data show that nonlethal oral doses of benzene can impact the nervous, hematological and
immunological systems. As with orally administered benzene, the targets for nonlethal concentrations of
inhaled benzene include the nervous, hematological, and immunological systems. Subchronic and
chronic exposures to benzene vapors induce a progressive depletion of the bone marrow and dysfunction
of the hematopoietic system. Benzene may also have long-term effects on the central nervous system
Workers exposed to benzene for 0.5 to 4 years exhibited EEG changes and atypical sleep activity
consistent with neurotoxicity. Others exposed to benzene concentrations of 210 ppm for 6-8 years had
peripheral nerve damage. Benzene does produce developmental effects (fetal toxicity but not
malformations) in the offspring of treated animals.
Benzene is carcinogenic in humans and animals by inhalation and in animals by the oral route of
exposure. Occupational exposure to benzene has been associated mainly with increased incidences of
various leukemias among workers.
Based on "several studies of increased incidence of nonlymphocytic leukemia from occupational
exposure, increased incidence of neoplasia in rats and mice exposed by inhalation and gavage benzene
C-4
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has been placed in the EPA weight-of-evidence classification A, human carcinogen. The oral and
inhalation slope factors for benzene are 0.029 (mg/kg/day)"1
BENZO FA1PYRENE fBAPl
Benzo (a)pyrene is the most extensively studied member of polynuclear aromatic hydrocarbons (PAHs)
inducing tumors in multiple tissues of virtually all laboratory species tested by all routes of exposure.
Benzo (a)pyrene is readily absorbed across the Gl and respiratory epithelia. Benzo (a)pyrene was
distributed widely in the tissues of treated rats and mice, but primarily to tissues high in fat such as
adipose tissue and mammary gland.
Human data specifically linking benzo[a]pyrene (BAP) to a carcinogenic effect are lacking. There are
however, multiple animal studies in many species demonstrating BAP to be carcinogenic following
administration by numerous routes. In addition, BAP has produced positive results in numerous
genotoxicity assays.
The data for animal carcinogenicity is sufficient. Repeated BAP administration has been associated with
increased incidences of total tumors and of tumors at the site of exposure. Benzo [ajpyrene has been
shown to cause genotoxic effects in a broad range of prokaryotic and mammalian cell assay systems.
The verified a slope factor for oral exposure to benzo(a)pyrene of 7.3 per mg/kg/day, based on several
dietary studies in mice and rats. Neither verified nor provisional quantitative risk estimates were available
for the other PAHs in Group B2.
CHROMIUM
In nature, chromium (III) predominates over chromium (VI). Little chromium (VI) exists in biological
materials, except shortly after exposure, because reduction to chromium (III) occurs rapidly. Chromium
(III) is considered a nutritionally essential trace element and is considerably less toxic than chromium (VI).
Acute oral exposure of humans to high doses of chromium (VI) induced neurological effects, Gl
hemorrhage and fluid loss, and kidney and liver effects. An NOAEL of 2.5 mg chromium (VI) /kg/day in a
one-year drinking water study in rats and an uncertainty factor of 300 was the basis of a verified RfD of
0.003 mg/kg/day for chronic oral exposure. An NOAEL (No effects were observed in rats consuming 5%
chromium (lll)/kg/day in the diet for over two years) of 1,468 mg/kg-day for chromium (III) and an
uncertainty factor of 100 was the basis of the RfD of 1.5 mg/kg/day for chronic oral exposure.
Occupational (inhalation and dermal) exposure to chromium (III) compounds induced dermatitis. Similar
exposure to chromium (VI) induced ulcerative and allergic contact dermatitis, irritation of the upper
respiratory tract including ulceration of the mucosa and perforation of the nasal septum and possibly
kidney effects.
A target organ was not identified for chromium (III). The kidney appears to be the principal target organ
for repeated oral dosing with chromium (VI). Additional target organs for dermal and inhalation exposure
include the skin and respiratory tract.
IRON
No toxicity information is available for iron. The RfD for iron (0.3 mg/kg/day is based on allowable intakes
rather than adverse effect levels.
MANGANESE
Manganese is an essential trace element in humans that can elicit a variety of serious toxic responses
upon prolonged exposure to elevated concentrations either orally or by inhalation. The central nervous
C-5
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system is the primary target. Initial symptoms are headache, insomnia, disorientation, anxiety, lethargy,
and memory loss. These symptoms progress with continued exposure and eventually include motor
disturbances, tremors, and difficulty in walking, symptoms similar to those seen with Parkinsonism
These motor difficulties are often irreversible.
Effects on reproduction (decreased fertility, impotence) have been observed in humans with inhalation
exposure and in animals with oral exposure at the same or similar doses that initiate the central nervous
system effects. An increased incidence of coughs, colds, dyspnea during exercise, bronchitis, and
altered lung ventilatory parameters have also been seen in humans and animals with inhalation exposure.
A chronic and subchronic RfD for drinking water has been calculated by USEPA from a human no
observed adverse-effect level (NOAEL). The NOAEL was determined from an epidemiological study of
human populations exposed for a lifetime to manganese concentrations in drinking water ranging from
3.6-2300 ug/L. A chronic and subchronic RfD for dietary exposure has been calculated by USEPA from
a human NOAEL which was determined from a series of epidemiological studies. A reference
concentration (RfC) for chronic inhalation exposure was calculated from a human LOAEL for impairment
of neurobehavioral function from an epidemiological study.
NICKEL
Nickel is a naturally occurring element that may exist in various mineral forms. It is used in a wide variety
of applications including metallurgical processes and electrical components, such as batteries. Some
evidence suggests that nickel may be an essential trace element for mammals. The absorption of nickel
is dependent on its physicochemical form, with watersoluble forms being more readily absorbed. Toxic
effects of oral exposure to nickel usually involve the kidneys with some evidence from animal studies
showing a possible developmental/reproductive toxicity effect.
Inhalation exposure to some nickel compounds will cause toxic effects in the respiratory tract and immune
system. Acute inhalation exposure of humans to nickel may produce headache, nausea.respiratory
disorders, and death. Asthmatic conditions have also been documented for inhalation exposure to nickel.
No clinical evidence of developmental or reproductive toxicity were reported for women working in a
nickel refinery, but possible reproductive and developmental effects in humans of occupational exposure
to nickel have been reported. Furthermore, sensitivity reactions to nickel are well documented and
usually involve contact dermatitis reactions resulting from contact with nickel-containing items such as
cooking utensils, jewelry, coins, etc.
A chronic and subchronic oral reference dose (RfD) of 0.02 mg/kg/day for soluble nickel salts is based on
changes in organ and body weights of rats receiving dietary nickel sulfate hexahydrate for 2 years. The
primary target organs for nickel-induced systemic toxicity are the lungs and upper respiratory tract for
inhalation exposure and the kidneys for oral exposure. Other target organs include the cardiovascular
system, immune system, and the blood.
ZINC AND ZINC COMPOUNDS
Zinc is an essential element with recommended daily allowances ranging from 5 mg for infants to 15 mg
for adult males. Zinc is present in all tissues with the highest concentrations in the prostate, kidney, liver,
heart, and pancreas.
In humans, acutely toxic oral doses of zinc cause nausea, vomiting, diarrhea, and abdominal cramps and
in some cases gastric bleeding. Gastrointestinal upset has also been reported in individuals taking daily
dietary zinc supplements for up to 6 weeks. There is also limited evidence that the human immune
system may be impaired by subchronic exposures.
Chronic oral exposures to zinc have resulted in hypochromic microcytic anemia associated with
hypoceruloplasminemia, hypocupremia, and neutropenia in some individuals. Anemia and pancreatitis
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were the major adverse effects observed in chronic animal studies. Teratogenic effects have not been
seen in animals exposed to zinc; however, high oral doses can affect reproduction and fetal growth.
The reference dose for chronic oral exposure to zinc is under review by USEPA; the currently accepted
RfD for both subchronic and chronic exposures is 0.3 mg/kg/day based on a decrease in erythrocyte
superoxide dismutase (ESOD) in adult women after 10 weeks of zinc exposure. Zinc is placed in weight-
of-evidence Group D, not classifiable as to human carcinogenicity due to inadequate evidence in humans
and animals.
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