Superfund Record of Decision Naval Weapons Station (WPNSTA) OUs 12, 13, 14, and 15, Yorktown, VA


PB99-963907
EPA541-R99-011
1999
EPA Superfund
Record of Decision:
Naval Weapons Station
(WPNSTA) OUs 12,13,14, & 15
Yorktown, VA
10/13/1998

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1.0
DECLARATION OF THE RECORD OF DECISION
1.1	Site Nam# and Location
Naval Weapons Station (WPNSTA) Yorktown, Yorktown, Virginia
Sites 6 and 7; Operable Units (OUs) XII, XIII, XIV, and XV
1.2	Statement of Basis and Purnoae
This Record of Decision (ROD) documents the selected remedial action to reduce the risks posed by
contaminated media at Sites 6 and 7 located at WPNSTA Yorktown, Yorktown, Virginia. Sites 6 and 7
have been divided into 4 OUs for remediation:
OUXII - Soil and Sediment at Site 7
•	Contaminated soil and sediment from the drainage ditch behind Plant 3. The ditch
received outfall from Plant 3 and was contaminated with nitramine/nitroaromatic
compounds including: 2,4,6,- trinitrotoluene (TNT), amino-dinitrotoluenes (amino-
DNTs), cyclotrimethylenenitramine (RDX) and cyclotetramethylenetetranitramine
(HMX). Soil and sediment were removed from the ditch to conduct a full scale pilot study
for the bioremediation of explosives contaminated media in 1996.
OUXIII - Site 6 - Flume Area
•	Soil and sediment from the Site 6 - Flume Area, which includes historic discharges from
Buildings 109 and 110, is contaminated with chlorinated volatile compounds including:
1,1,1-trichloroethane (TCA), trichloroethene (TCE), and tetrachloroethene (PCE);
nitramine/nitroaromatic compounds including TNT, aminoDNTs, dinitrotoluenes, HMX,
RDX, 1,3,5-trinitrobenzene; and inorganics including nickel and zinc.
•	Nitramine/nitroaromatic contaminated explosives residue in Building 109 (RCRA Area of
Concent C and Solid Waste Management Unit 179) exists and could be released to the
Site 6 - Flume Area if not addressed.
OU XIV - Site 6 - Excavated Area
•	Surface soil in the Site 6 - Excavated Area is contaminated with cadmium and zinc.
OUXV Site 6 - Impoundment Area Surface water and Sediment, Site 7 Surface Water, Site 6 and 7
Groundwater
•	The Site 6 - Impoundment Area is located at the terminal end of die Site 6 - Flume Area.
Sediment in the Site 6 - Impoundment is contaminated with nitramines/nitroaromatics,
chlorinated volatile organ ics and inorganics. The highest concentrations of these
contaminants occur at depth.
•	Groundwater beneath Site 6 and 7, which is not currently used as a potable water source,
is contaminated with chlorinated volatile organics, nitramines/nitroaromatics, and
inorganics. It could also act as a potential source of contamination to Site 6 and Site 7
surface water.

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Remedial action was chosen in accordance with the Comprehensive Environmental Response,
Compensation, and Liability Act of 1980 (CERCLA) as amended by die Superfund Amendments and
Reauthorization Act (SARA) of 1986, and, to the extent practicable, with the National Oil and Hazardous
Substances Pollution Contingency Plan (NCP). Hie information supporting the decisions on the selected
remedy is contained in the administrative record. Section 2.2.2 lists major documents contained in the
administrative record.
The Commonwealth of Virginia concurs with the selected remedy.
*
Actual or threatened releases of hazardous substances from OUs XIII, XTV, and XV, if not addressed by
implementing die remedial action selected in this ROD, may present an imminent and substantial danger to
human health and the environment. No further action is proposed for OU XII because risks posed to
human health and the environment have been mitigated by a removal action conducted in support of a full-
scale Pilot Study for the bioremediation of explosives-contaminated sediment conducted in 1996.
1-4 Description of the Selected Remedy
The remedy for OU XII, OU XIII, OU XTV, and OU XV is part of a comprehensive environmental
remediation currently being performed at WPNSTA Yorktown under the Department of Defense (DoD)
Installation Restoration (IR) Program.
The removal and treatment of soil/sediment and Building 109 residue at OU XIII, Site 6-Flume Area, and
a soil cover at OU XIV, Site 6-Excavated Area, address the principal threat to human health and the
environment by eliminating source materials and potential release of these contaminants to the
environment. They also mitigate the potential for direct contact with soil at the Site 6-Excavated Area.
Long-term monitoring of sediment, surface water, and groundwater at OU XV will: 1) evaluate the
efficacy of the removal planned for the Site 6-Flume Area in removing a potential source of continuing
contaminant release and 2) provide temporal data about conditions in the Site 6-Impoundment Area and
the quality of shallow groundwater which may interconnect with Sites 6 and 7 surface water and
sediments. Major components of the selected remedies for OUs XII, XIII, XIV, and XV include:
OUXII- Site 7 - Drainage Area
• No Further Action for OU XII. Approximately 800 cubic yards of nitramine/nitroaromatic
and inorganic contaminated soil and sediment were removed as part of a bioremediation
pilot study conducted in 1996. Soil and sediment have been cleaned up to levels
appropriate for commercial/industrial use, which is the current land use and the
most likely future land use for this site. Residual levels of contamination,
- however, make the site inappropriate for residential uses. Consequently,
residential use is prohibited as part of the remedy.
OUXIII - Site 6 - Flume Area
Excavation of nitramine/n itroaromatic-, chlorinated volatile-, and inorganic-contaminated
soil and sediment from the Site 6 - Flume Area.

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• Ex situ bioremediation of soil and sediment excavated from the Site 6 - Flume Area.
Nitramlne/nitroaromatics are readily degraded by the process, but chlorinated voiatiles
may be recalcitrant to degradation. If voiatiles do not degrade during a reasonable cycle of
ex situ treatment, a contingency remedy (low temperature thermal desorption) will be
employed to remove remaining chlorinated voiatiles from the soil.
• Habitat restoration of the Site 6 - Flume Area.
• Pressure washing of the trenches (SWMU 179), and residue removal and pressure
washing of the trenches under Building 109 (AOC C).
• Removal of explosives-contaminated residue from SWMU 179 and treatment by burning
at the Station's thermal treatment unit.
• This site will be cleaned up to levels appropriate for commercial/industrial use, which is
the current land use and the most likely future land use for this site. Residual levels of
contamination, however, will make the site inappropriate for residential uses.
Consequently, residential use is prohibited as part of the remedy.
OU XIV - Site 6 - Excavated A rea >
• Grading and placement of backfill as a soil cover ( minimum 8 inches) to prevent contact
with cadmium and zinc-contaminated surface soil by terrestrial ecological receptors at the
Site 6 - Excavated Area. No long-term monitoring will be necessary.
• Activities that interfere with or compromise the integrity of the cover at this site
will be prohibited.
OUXV - Site 6 - Impoundment Area Surface Water and Sediment, Surface Water at Site 1, Groundwater
at Site 6 and 7
Long-term monitoring of surface water and sediment will be conducted for
nitramines/nitroaromatics and chlorinated volatile organics and inorganics (including
nickel and zinc) in the Site 6-Impoundment Arm. Long-term monitoring of the
groundwater throughout Sites 6 and 7 for nitramines/nitroaromatics, chlorinated voiatiles
and inorganics will also be conducted, but this is not die final remedy for groundwater.
Groundwater at Sites 6 and 7 will be addressed in a separate OU after USEPA Region III
completes a watershed study for Felgates Creek scheduled for September, 1998. Long-
term monitoring of surface water at Site 7 for similar contaminants.
Specifics of the long-term monitoring program will be developed by the Navy, the United
States Environmental Protection Agency (USEPA) Region III, and Commonwealth of
Virginia Department of Environmental Quality (DEQ) and presented in a Long-Term
Monitoring Work Plan, a primary document under the WPNSTA Yorktown Federal
Facilities Agreement (FFA).

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The seketad remedy (inchidmg the contingency remedy for OU XIII) is protective of human health and the
¦crviroomont, complM* with federal and itatr requirements that are legally ipplfcable or relevant and
appjopriart to the remedial action (^RARs), and ii eott-eflbctive. Ttoreotedty uae* pennanentsolutioa*
a^aheniative treatment technotogies to ibemaxhniim extant practicable. Tbe sej«ctcd remedy meets the
statutory preference for treatment at OU XDL and OU XSJ, but not OU XIV or OU XV, who* treatment of
confammants is DOC practicable. At OU XII, soil and aedbsec* at Site 7. bioremedlation was used to treet
«xploefte*-«ontaminaied soil as pait of a biofornedktkMi pilot study. AtOUXIII bioremedlalkw will be
uaad to treat nitramtoes and nitiueiotuatka; ifchfodnatedvohtilae do rot degrade during a reasonable
cycle ofbiorcmcdiation, a contingency r*m*dy (low tenapemtoee thermal desoiptioa) will be
employed to remove remaining chlorinated volatika firom die aail.
Beoauae the remedy will result in hazardous sabstaucea remaining oo-alte above conservative health-based
levels atallOUs, a review will be conducted within five yean after cccunaocement of remedial «ctjon to
catun	>f human health and die enviionment is maintained.
Captain S.A. Denham, Commanding Officer
gdctfttg-
Naval W<
Abraham F«xdaf,ActngDiviik)n Director
Dan
Httardou* WastaManagemeqt
United Statea Environmental Protection Agency, Region IU

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2.0 decision summary
1
2.1 Site NiHHfr AurinPfiwnptiffli
WPNSTA Yorktown is a 10,624 acre installation located on the Virginia Peninsula in York and James City
Counties and the City of Newport News (Figure 2-1). The Station is bounded on the northwest by the
Naval Supply Center Cheatham Annex, the Virginia Emergency Fuel Farm, and the future community
development of Whittaker's Mill; on the northeast by the York River and the Colonial National Historic
Parkway; on the southwest by Route 143 and Interstate 64; and on the southeast by Route 238 and the
community of Lackey. The locations of Sites 6 and 7 are presented in Figure 2-2.
2.1.1 Site 6 - Explosives-Contaminated Wastewater Impoundment
The Site 6 study area covers approximately 94 acres and includes the area surrounding Buildings 109, 110,
and 501; the explosives-contaminated wastewater impoundment ( a portion of OU XV) with the
associated flume (OU XIII); an excavated area (OU XTV); and a tributary to Felgates Creek. The Site 6
study area generally slopes to the west toward the Site 6 - Impoundment Area. The buildings in the study
area are surrounded by earthen berrns that affect surface water runoff direction. Currently, the Site 6 -
Impoundment Area collects only surface runoff from the area between Buildings 109 and 110. A system
of trenches and piping originating from Building 109 carried discharge to the Site 6 - Flume Area and the
Site 6 - Impoundment Area during operations. Building 109 is no longer in use. Figure 2-3 illustrates the
Site 6 - Flume Area.
North of the Site 6 - Impoundment Area, an excavated area has been identified. This area is currently
wooded, but concrete rubble and miscellaneous debris are evident in the area. The history of the Site 6 -
Excavated Area is not documented. The area may have been a former soil borrow pit, from which soil was
obtained to construct the dam for the impoundment.

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2.1.2 Site 7 - Plant 3 Explosives-Contaminated Wastewater Discharge Area
Site 7 is a 300-foot long (approximate length) drainage area located adjacent to wetlands and along a small
tributary to Felgates Creek, approximately one mile upstream from the confluence of Felgates Creek and
the York River. The buildings in the study area are surrounded by earthen berms that affect surface water
runoff direction. The Site 7 study area generally slopes toward a ravine located along the southern portion
of the study area. The actual study area for Site 7 covers approximately 62 acres and includes the area
surrounding Buildings 375, 502, 503, and 504 (collectively known as Loading Plant 3) as well as a
drainage area. Sediment and some soil along the banks of the drainage area (OU XII) were removed for
the full-scale Pilot Study for the bioremediation of explosives-contaminated soil conducted in 1996. The
removal focused on soil and sediment in the Site 7 - Drainage Area containing concentrations of
nitramine/nitroaromatic compounds exceeding human health based remediation levels derived for
commercial/industrial property use. The Site 7 - Drainage Area discharges to a small tributary of Felgates
Creek.
2.2 Site History and Enforcement Activities
2.2.1 Site History
Originally named the U.S. Mine Depot, WPNSTA Yorktown was established in 1918 to support the laying
of mines in the North Sea during World War I. For 20 years after World War I, the depot received,
reclaimed, stored, and issued mines, depth charges, and related materials. During World War H, the
facility was expanded to include three additional TNT loading plants and new torpedo overhaul facilities.
On August 7, 1959, the depot was redesignated the U.S. Naval Weapons Station. Currently, the primary
mission of WPNSTA Yorktown is to provide ordnance, technical support, and related services to sustain
the war-fighting capability of the armed forces in support of national military strategy.
The Site 6 - Impoundment Area was formerly used during the years of 1942 through 1975 as a settling
basin for nitramine-contaminated wash down water. The contaminated wastewater was generated from the
explosives reclamation facility at Building 109 and from weapons loading operations at Building 110.
This wastewater flowed ^long concrete flumes in what has been designated as the Site 6 - Flume Area.
The explosives reclamation facility released solvents such as TCE and TCA and nitramine/nitroaromatic
compounds such as TNT and RDX to the Site 6 - Impoundment Area. The weapons reclamation
operations released solvents and nitramine compounds to the Site 6 - Impoundment Area by means of a
concrete-lined drainage channel or flume that emanates from Building 109. In 1975, a carbon adsorption
tower was installed to treat the contaminated wastewater before it was discharged from Buildings 109 and
110 into the Site 6 - Flume Area. A National Pollutant Discharge Elimination System (NPDES) Permit
was granted by the USEPA Region III to allow this discharge. In 1986, the effluent from the tower was
diverted to the sanitary sewer and ultimately to the Hampton Roads Sanitation District (HRSD). The Site 6
- Impoundment Area currently collects only surface water runoff from the area between Buildings 109 and
110. Based on a Resource Conservation and Recovery Act (RCRA) Solid Waste Management Unit
Investigation at WPNSTA Yorktown, the EPA Office of RCRA programs issued a final report in
December 1992 which identified 94 areas at WPNSTA Yorktown that require additional investigation
under the RCRA. Two of these areas are AOC C - Building 109 Contaminated Structure and SWMU 179
- Building 109 trenches and piping.
The history of the Site 6 - Excavated Area identified north of the Site 6 - Impoundment Area is not
documented. The area may have been a former soil borrow pit, from which soil was obtained to build the
dam for the Impoundment Area.

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The Site 7 - Drainage Area received nitramine-contaminated wastewater from Loading Plant 3
(Building 375, 502, 503, and 504) between 1945 and 1975. In 1975, a carbon adsorption tower was
installed to treat the contaminated wastewater prior to discharge to the Site 7 - Drainage Area. An NPDES
Permit was granted by USEPA Region III to allow this discharge. In 1986, the discharge from the tower
was diverted to the sanitary sewer and ultimately to the HRSD. The Site 7 - Drainage Area did not receive
discharge from Plant 3 after this date. Soil/sediment from the Site 7 - Drainage Area was removed in
1996 as part of the full-scale Pilot Study for bioremediation of explosives contamination and the area
restored.
2.2.2 Enforcement Activities
On October 15, 1992, WFNSTA Yorktown was included on the National Priorities List (NPL) because of
the facility's proximity to wetlands and the potential impact on the surrounding environment. A FFA
between USEPA Region III, the Commonwealth of Virginia, and the Department of the Navy (DoN) was
finalized in August of 1994 for WPNSTA Yorktown. The FFA covers the investigation, development,
selection, and implementation of response actions, satisfying WPNSTA Yorktown's RCRA corrective
action obligations as well as appropriate provisions of CERCLA for all sites, SWMUs, and RCRA AOCs.
In December 1996, a full-scale Pilot Scale study was conducted using Site 7 - Drainage Area soil/sediment
to determine if an aqueous-phase, ex-situ biocell could remediate explosives-contaminated soil. Therefore,
the source of nitramine/nitroaromatic contamination at Site 7 was removed as part of this study. No other
documented enforcement activities have been conducted at either Sites 6 or 7 under the FFA.
The following documents provide details of the site investigations and assessments of cleanup actions for
OUs XII, XIII, XIV, and XV.
!
• C.C. Johnson & Associates, Inc. and CH2M Hill. Initial Assessment Study of Naval
Weapons Station. Yorktown. July 1984.
® Dames & Moore. ConfinH8tli?lLStudiLStCP IA (VsnfiS9ttOB)t Rwfld QtWi NSYll
Weapons Station. Yorktown. Virginia June 1986.
• Dames & Moore. Confirmation Study Step IA (Verification) Round Two. Naval
Weapons Station. Yorktown. Virginia. June 1988.
• Baker Environmental, Inc. and Roy F. Weston, Inc. Focused Biological Sampling and
Preliminary Risk Evaluation Naval Weapons Station. Yorktown. Virf inia. July 1993.
• Baker Environmental, Inc. And Roy F. Weston, Inc. Final Round One Remedial
Investigation Reyort for Sites 1-9. 11. 12. 16-19. Naval Weapons Station. Yorktown.
Virginia. July 1993.
• Baker Environmental, Inc. Final Habitat Evaluation Report (WPNSTA Sites 1. 2.3.4.6.
7. 8. 9.11.12. 16. 17. 18. 19. and 211 July 1995.
® Baker Environmental, inc. Final PilPtStwIv ftspgrt for the Explosives-Contaminated Soil
at the Naval Weapons Station Yorktown. Yorktown. Virginia. July 1997.
Baker Environmental, Inc. Interim Final Remedial Investigation Round Two Report.
Naval Weapons Station. Yorktown. Virginia. February 1998.

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2.23 History of Previous Investigations
The purpose of the Initial Assessment Study (IAS) (C.C. Johnson & Associates, Inc. and CH2M Hill, July
1984) was to identify and assess sites posing a potential threat to human health and/or the environment. A
total of 19 potentially contaminated sites were identified based on information from historical records,
aerial photographs, field inspections, and personnel interviews. The IAS concluded that 15 of the 19 sites,
including Sites 6 and 7, were of sufficient threat to human health or the environment to warrant
Confirmation Studies.
A Confirmation Study was then conducted for the IS sites and two rounds of data were obtained. The first
round of data was collected in the winter of 1986. This effort was documented in the "Confirmation Study
Step IA (Verification), Round One," (Dames & Moore, June 1986). The second round of sampling was
conducted during November-December 1987 and results of the analyses were presented in the
"Confirmation Study Step IA (Verification), Round Two," (Dames & Moore, June 1988).
The 15 sites, including Sites 6 and 7, were recommended for further study and were evaluated as part of
the Round One Remedial Investigation (RI) (July 1993). Soil, surface water, sediment and groundwater
samples were collected and analyzed for Target Compound List (TCL) organics, Target Analyte List
(TAL) inorganics, and nitramine/mtroaromatic compounds (explosives). Samples from Sites 6 and 7
indicated the presence of contamination in surface water and sediment. However, the nature and extent of
the contamination at Sites 6 and 7 was not completely defined by the results of the Round One RI.
Additional sampling was recommended for all media.
The Round Two RI and report for Sites 6 and 7 was completed in February of 1998. Additional soil and
sediment data indicated that contamination was present at both sites. These sample data were used as part
of the Feasibility Study (FS) Report (March 1998) to determine the extent of soil contamination. FS soil
data confirmed that the highest levels of explosives contamination were at the Site 6-Flume Area in
sediment.
A Supplemental Investigation to the Round Two RI was conducted in February 1996 at the Site 6-
Impoundment Area to collect additional data to delineate the potential extent of contamination within the
impoundment. The Supplemental Investigation included the collection of shallow soil samples and
sediment samples. Shallow soil samples were collected along the northern and eastern banks of the
impoundment and sediment samples were collected throughout the impoundment area. Analytical results
indicate that the sediments have been impacted by volatile organic compounds (VOCs), semivolatile
organic compounds (SVOCs), and nitramine compounds, particularly in the vicinity of the former
wastewater discharge area of the impoundment.
Following the Supplemental Investigation, USEPA was concerned that there was not enough data on
explosives contamination at AOC C and SWMU 179. Although these areas are encompassed by the Site 6
study area, USEPA believed that an insufficient number of samples had been collected in close proximity
to evaluate impacts on environmental media. As a result, fourteen additional soil samples were collected
in October 1996. The samples were collected at depths ranging from 0 to 4 feet below ground surface
(bgs). All of the samples were field tested for TNT and submitted to a laboratory for VOC analysis. The
TNT test kit results indicated that all of the soil samples collected had TNT concentrations less than 30
parts per million (ppm), the lower end of the detection limit. Soil samples were not sent to a laboratory for
TNT confirmation. Based on the data and information gained from the October 1996 sampling event, no
additional RCRA activities were needed at SWMU 179 and AOC C.
A full-scale Pilot Study to treat explosives-contaminated soil/sediment obtained from Site 7 was conducted

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between September and December of 1996. The purpose of the study was to determine the technical
implementability, effectiveness, and future costs of an anaerobic remediation technology used to treat
explosives-contaminated soil. Approximately 770 cubic yards of soil were excavated from the drainage
area leading to the tributary at Site 7. Soil with TNT concentrations exceeding 30 ppm was excavated and
sent to the newly-constructed biocell at another site at WPNSTA Yorktown, The TNT concentrations in
the soil entering the biocell averaged over 1,000 ppm. After treatment, the TNT concentrations ranged
from less than 1 ppm to 4 ppm. As a result of this full-scale Pilot Study, the source of contamination has
been removed from Site 7.
An ecological toxicity study was conducted on the sediment in the Site 6 - Flume Area at Site 6 in 1997,
The purpose of the study was to further define the extent of explosive contamination and to establish
toxicity-based site-specific cleanup goals for the explosive contaminants. In August, 1997, Baker collected
a series of sediment samples from the Site 6 - Flume Area. The sediment samples were submitted to an
off-site analytical laboratoiy and to an ecological toxicity laboratory for analysis. An acute (10-day) and a
chronic (28-day) ecological toxicity study were conducted on the sediments. The tests indicated that TNT
concentrations above a range of68,000 to 118,000 jig/kg may pose risks to benthic macroinvertebrates.
On February 11, 1998, a composite soil sample was collected from the Site 6-Flume Area (near the
concrete flumes) by Baker personnel. The soil sample was split with Grace Environmental (a treatability
study vendor) for a Soil Optimization Study to determine the ability of Daramend®, a proprietary
technology, to remediate volatiles and nitramines/nitroaromatics. Baker submitted the sample to mi off-site
laboratory for analysis ofTCL VOCs, SVOCs, pesticides/polychlorinated biphenyls (PCBs), nitrammes,
and TAL inorganics.
23 Highlight* «fCommunity P«rtieination ^
The Proposed Remedial Action Plan (FRAP) for Sites 6 and 7 was released to the public in May 1998 at
the four information repositories listed below:
• York County Public Library
8S00 George Washington Highway
Yorktown, VA 23692
(757) 890-3377
• Newport News City Public Library
Grissom Branch
366 Deshazor Drive
Newport News, VA 23608
(757)886-7896
« Gloucester Public Library
P.O. Box 367, Main Street
Gloucester, VA 23601
(804)693-2998
® Naval Weapons Station Yorktown
Environmental Directorate
Building 31-B, P.O. Drawer 160
Yorktown, VA 23691-0160
(757) 887-4775 (ext. 29) (Contact: Mr. Jeff Harlow)

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The notice of availability of this document was published May 10, 1998 in the Daily Press. A public
comment period was held from May 26, 1998 to July 11, 1998. A fact sheet that summarized the Proposed
Plan was distributed to attendees of the Public Meeting held at the York County Recreational Services
Meeting Room, 301 Godwin Neck Road, Yorktown, Virginia, on May 26, 1998. This meeting was held to
inform interested members of the community about the preferred remedial alternative under consideration.
Responses to comments received during the public comment period and a transcript of the Public Meeting
are included in the Responsiveness Summary in Section 3.0 of this document.
2.4 Scone and Role of the Remedy
The studies,at Sites 6 and 7 are part of comprehensive environmental investigations being conducted under
the IR Program at WPNSTA Yorktown. OU XII consists of soil, surface water, and sediment at Site 7.
Contaminated sediment was excavated from Site 7 and used in the full-scale Pilot Study for explosives-
contaminated soil remediation through bioremediation. No additional action is recommended for OU XII.
OU XIII consists of soil and sediment at Site 6-Flume Area and explosives-contaminated residue under
Building 109. The remedial action will consist of removing and treating approximately 20 cubic yards of
explosives-contaminated residue and pressure washing AOC C in order to prevent it from being a
secondary source of contamination for the Site 6-Flume Area. SWMU 179 will be pressure washed to
prevent any future potential releases from the building. Residue will be transported to an on-site burning
area for treatment. The Site 6-Flume Area soil/sediment contains concentrations of explosives that pose a
potential threat to human health and the environment. The sediment also contains concentrations of
volatiles and inorganics that pose a potential ecological risk. The soil/sediment will be excavated until
confirmation sampling indicates that all of the contamination has been removed and contaminants
remaining in soil are at concentrations equal to, or lower than, risk-based remediation levels (RLs),
Contaminated soil/sediment from the Site 6-Flume Area will be treated using an ex situ bioremediation
process. A contingency remedy may be necessary to remediate volatile organics to health based goals, [f a
reasonable cycle (cycle length is weather dependent) of ex situ biological treatment does not reduce
volatile organic contamination in soil/sediment to concentrations equal to, or below risk - based treatment
goals, low temperature thermal desorption may be employed to reduce chlorinated volatile organic
concentrations to health based levels. Successfully treated soil/sediment will be used at the Station as
clean fill. The Site 6 - Flume Area will be restored with clean fill and 4 inches of topsoil for revegetation.
The Site 6 - Flume Area and contaminant concentrations that exceed risk-based remediation levels (RLs)
are shown in Figures 2-4 and 2-5.
OU XV includes groundwater, surface water, and sediment at the Site 6 - Impoundment Area. Although
some potential for human health and ecological risk exists at the Site 6 - Impoundment Area, remediation
of the site would harm the surrounding ecological receptors by destroying habitat. As such, no active
remediation is recommended for the areas contaminated with nitramines/nitroaromatics, chlorinated
volatiles, and inorganics. Long-term groundwater, surface water, and sediment monitoring will be
conducted to determine if the surface water and groundwater in the Site 6 - Impoundment Area are
impacted by the sediment contamination or if contaminant concentrations are increasing or decreasing over
time. The Site 6 - Impoundment Area and contaminant concentrations that exceed risk-based remediation
levels are shown in Figure 2-4.
Potential for ecological risk exists at OU XIV (Site 6 - Excavated Area). To protect the environment, a soil.
cover will be placed over the Site 6 - Excavated Area to prevent ecological receptors from coming into
contact with the zinc and cadmium-contaminated surface soil. The cover will consist of 8-inches of fill
and 4-inches of topsoil for revegetation. The Site 6 - Excavated Area and contaminant concentrations that

-------
exceed risk-based remediation levels are shown in Figure 2-4,

-------
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-------
2-5 Summary of Site Chflrayftlfrltirt
OU XII - Site 7 - Drainage Area
• Approximately 800 cubic yards of soil and sediment at the Site 7 - Drainage Area was
contaminated with nitramines/nitroaromatics including TNT (as high as 40,000 mg/Kg),
HMX ( as high as 3,200 mg/Kg) and RDX (as high as 14,000 mg/Kg). This soil and
sediment was removed during a full-scale Pilot Study for ex-situ bioremediation
conducted at the biocell at Site 22 at WPNSTA. The contaminants TNT and RDX could
cause both noncarcinogenic and carcinogenic health effects in exposed humans. The
most recent toxicity data for HMX indicates that only systemic (noncarcinogenic) health
effects could occur in humans subsequent to exposure. TNT, RDX and HMX are only
slightly mobile in environmental media, relative to very mobile organic contaminants such
as the chlorinated volatile organics.
OUXI11 - Site 6 - Flume Area
• Approximately 1,000 cubic yards of soil and sediment in the Site 6 - Flume Area is
contaminated with nitramines, nitroaromatics, and VOCs. Contaminants of concern at the
Site 6 - Flume Area include TOT (as high as 93,000 mg/Kg), RDX ( as high as 3,900
mg/Kg), TCE (as high as 2,600 mg/Kg), nickel (as high as 232J mg/Kg) and zinc (as high
as 698 mg/Kg). TCE could cause both systemic health effects as well as carcinogenic
health effects in exposed human receptors. Zinc is a systemic toxicant and is not
considered to be a known carcinogen. TCE and other chlorinated volatiles are very
mobile in environmental media by virtue of their corresponding water solubility and
relatively low octanol/water partitioning coefficients. Zinc is relatively immobile in
environmental media, as are most inorganic contaminants.
OUXIV - Site 6 - Excavated Area
• Soil from OU XIV may have been excavated to build the dam at the Impoundment Area.
Approximately 500 cubic yards of soil in the Site 6 - Excavated Area is contaminated with
cadmium (13.4 mg/Kg) ami zinc (1,950 mg/Kg). These inorganic constituents pose a
potential ecological risk. Cadmium and zinc could cause systemic health effects in
potentially exposed human receptors. Both contaminants are considered to be relatively
immobile in environmental media.
OU XV ' Site 6 - Impoundment Area Surface Water and Sediment, Surface Water at Site 7, Groundwater
at Site 6 and 7
• The Site 6 - Impoundment Area is located at the terminal end of the Site 6 - Flume Area.
• Sediment in the Site 6 - Impoundment is contaminated with nitramines/nitroaromatics,
chlorinated volatile organics and inorganics. The highest concentrations of these
contaminants occur at depth where TNT was detected at a maximum concentration of
2,500 mg/Kg and 4-amino-2,6-DNT was detected at a maximum of 520 mg/Kg. The
contaminant 4-amino-2,6-DNT is a systemic toxicant that is relatively immobile in
environmental media.

-------
• Groundwater beneath Site 6 and 7, which is not currently used as a source of potable
water, is contaminated with chlorinated volatile organics including TCE which was
detected at a maximum concentration of 370 ug/L, nitramines/nitroaromatics including
HMX (7.6 ug/L) and RDX (16 ug/L), and inorganics. It could also act as a potential
source of contamination to Site 6 surface water where volatile organics such as TCE were
detected at concentrations of 15 ug/L during the Round One RI.
Nitramines/nitroaromatics were also detected in surface water samples taken from the
Site 6 - Impoundment Area.
2.6 sammary of Site Riata
A baseline risk assessment (RA) was conducted as part of the Sites 6 and 7 Round Two Remedial
Investigation Report (Baker, 1998). Both human health and ecological RAs were conducted. This section
summarizes the results of the baseline RA and those contaminants associated with unacceptable human
health risks and potential adverse ecological effects.
Human health risks are described by evaluating noncarcinogenic (systemic) and carcinogenic health
effects. Reference dose (RfDs) values have been developed by EPA for indicating the potential for
adverse health effects from exposure to contaminants of potential concern (COPCs) exhibiting
noncarcinogenic effects. RfDs, which are expressed in units of mg/Kg-day, are estimates of lifetime daily
exposure levels for humans, including sensitive individuals. RfDs are derived from human
epidemiological data or animal studies to which uncertainty factors have been applied to account for the
use of animal data to predict effects on humans. These uncertainty factors help ensure that the RfD's
will not underestimate the potential for adverse noncarcinogenic effects to occur.The potential for
noncarcinogenic effects is evaluated by comparing an exposure level over a specified time period
(e.g, lifetime) with a reference dose for a similar exposure period. The ratio of exposure to the
reference dose is called a hazard quotient (HQ). HQ values are then summed to produce hazard indices
(His) for each potential receptor and means of exposure (dermal, ingestion, inhalation). If a hazard index
is greater than or equal to 1.0, the contaminants included in the hazard index are re-examined to see
whether they affect the same target organ (e.g., liver). If they do not, new hazard indices are computed,
summing HQ values only for contaminants that affect a single target organ. Contaminants that affect a
single target organ and produce a hazard index greater than or equal to 1.0 are considered to be chemicals
of concern (COCs) and remedial action is considered to reduce the risk of adverse, noncarcinogenic health
effects in the exposed population.
Carcinogenic human health risks are expressed as a probability known as an incremental lifetime cancer
risk (ICR). This risk is the incremental probability that an individual will develop cancer in his or her
lifetime following exposure to a contaminant. These risks are usually expressed in scientific notation
(e.g., 1 x 10~*). An incremental lifetime cancer risk of 1 x 10"6, for example, indicates that an
individual who receives an estimated reasonable maximum exposure to contaminants at a site has a 1
in 1,000,000 chance of developing cancer as a result This is referred to as an "incremental lifetime
cancer risk" because it would be in addition to the risks of cancer individuals face from other causes
(for example, smoking). The ICR values for all potentially carcinogenic COPCs to which a person may
be exposed are added together. The total ICR value is compared to EPA's generally acceptable risk range
of 1 x 10"* to I x I0*6. The generally acceptable risk range is the range of cancer risks considered to be
acceptable at most sites under most circumstances. For example, the upper end of US EPA's acceptable
risk range, 1 x 10"*, means that one additional cancer case is estimated to occur in an exposed population of
10,000 as a result of exposure to the site. It can also mean that an individual with an ICR value of 1 x 10"V
has an estimated increased probability of 0.01% of contracting cancer following exposure over the course'

-------
of a lifetime.
ICR values of 10*4 or greater are evaluated to identify those contaminants in environmental media
responsible for 95% of the unacceptable risk. These chemicals are considered to be COCs and remedial
action is considered to reduce the cancer risk.
Because WPNSTA Yorktown was placed on the National Priority List (NPL) as a result of ecological
concerns (proximity to wetlands, etc.) potential ecological receptors are also evaluated at each site.
Terrestrial and aquatic receptors are evaluated by: 1} a general comparison to existing toxicity criteria; and
2) conservative contaminant uptake modeling to establish a site specific body burden in an animal or
organism and a comparison to published toxicity data for a similar animal or organism. Both phases of the
ecological risk assessment culminate with the calculation of ecological HQs. Ecological HQ values greater
than or equal to 1.0 indicate the potential for adverse effects on die environment, and chemicals producing
these values are considered ecological contaminants of concern. Remediation of these contaminants must
be considered carefully, so that the selected remedy does not create more short-term harm to the ecological
receptors than is produced by leaving contaminants in place. For example, scientists must decide if more
damage will be done by removing sediments and destroying a wetland or by having contaminants remain
in the sediment.

-------
2.6.1 Human Health Risk Assessment
Because of the nature of activities conducted at and around Sites 6 and 7, potential current human
exposure is limited. Both sites tie within the Explosive Safety Quantity Distance (ESQD) arc (associated
with the storage of munitions) and inside the restricted area of the Station. Residential development is not
permitted in these areas. Current potential human receptors evaluated in the baseline RA for Sites 6 and 7
include;
• Adolescent (7-15 years old) Trespassers
• AduJt Trespassers
• Civilian Adult Workers
The adult and adolescent trespasser scenario is unlikely, but assumes that Station personnel and adolescent
family members would trespass onto the site for recreational purposes. The exposure potential was
assumed to occur up to 143 days per year for 4 years. This estimate is conservative because current
property use restrictions prohibit this type of exposure at Sites 6 and 7.
The civilian adult worker scenario assumes that workers could potentially be exposed to contaminants in
surface soil, airborne dust from surface soil, surface water, and sediment during cutting/clearing of tall
grasses and trees or other general maintenance activities. This would occur infrequently so the potential
exposure was assumed to be 14 days per year, 8 hours per day for 25 years.
Future potential human receptors evaluated in the baseline RA for Sites 6 and 7 include:
• Future On-Site Adult and Young Child (1-6 years old) Residents
• Future Adult and Adolescent (7-15 years old) Recreational Users at Felgates Creek and
Tributaries
• Future On-Site Adult Construction Workers
• Future On-Site Adult Commercial Workers
Future residential development is unlikely at Sites 6 and 7 because they fail within the restricted area of the
Station. However, the future on-site adult and young child resident scenario was evaluated to address all
types of potential exposure and provide a conservative estimate of future human risk. Future adult and
young child residents were evaluated for potential exposure to groundwater, surface soil, surface water,
and sediment. An exposure frequency for surface soil of 350 days per year with durations of 24 years for
adults and 6 years for child residents was used. For groundwater, surface water, and sediment, an exposure
frequency of 40. days per year for the same durations as for surface soil was assumed.
Groundwater was also evaluated as part of die future residential scenario. The shallow aquifers (Cornwallis
Cave and Upper Yorktown) are not currently used as a source of potable water. Although pump teste were
not performed for the Cornwallis Cave or Upper Yorktown-Eastover aquifers in the vicinity of Sites 6 and
7, these aquifers can produce low yields (0 to 10 gallons per minute throughout WFNSTA Yorktown)
(Brockman, et ai., 1997) and contain naturally-occurring concentrations of inorganics including iron,
manganese, and zinc in excess of Secondary Maximum Contaminant Levels (SMCLs). Groundwater was
evaluated in the baseline RA for non-potable use, considering a beneficial use scenario such as lawn
watering and car washing by future residents., Potential human health risks derived assuming a beneficial
use scenario for groundwater fall within the generally acceptable target risk range, but the potential effects
on the water quality in the Site 6 - Impoundment Area and the ecology have not been determined.

-------
The following subsections present a summary of the human health risk assessment, unacceptable risks, and
the role of the selected remedy in addressing unacceptable risks.
Site 6
Tables 2-1 and 2-2 present COPCs for affected media at Site 6. Tables in Appendix A include
concentrations for COPCs at Site 6,
ICR values at Site 6 fall within USEPA's acceptable risk range for all environmental media assuming
future residential property use (Table 2-3). Cumulative HI values, the sum of all HQs, exceed 1.0 for
future resident children exposed to aluminum, arsenic, antimony, cadmium, iron, and manganese in soil.
Individual HQ values calculated specifically for these contaminants do not exceed 1.0. These
contaminants do not affect similar target organs; therefore, adverse noncarcinogenic human health risks
are not expected to occur following residential exposure to Site 6 soil at any area.
The presence of 4-amino-2,6-DNT; TNT; and iron in the Site 6-Impoundment Area sediment produces
cumulative HI values in excess of 1.0 for both exposed children and adults. Individual contaminant HQs
do not exceed 1.0, even though TNT and 4-amino-2,6-DNT HQ values are summed because the liver
would most likely be the target organ for these contaminants. Under these circumstances, these
contaminants do not pose an unacceptable health risk.
Table 2-4 presents ICR and HI values for potential adult and adolescent trespassers. ICR values for all
environmental media evaluated at Site 6 fall within USEPA's acceptable risk range of 1 x 10~* to 1 x 10"6.
HI values are below 1.0 for all media with the exception of the Site 6 - Impoundment Area sediment,
where 4-amino-2,6-DNT produces HQ values in excess of 1.0 under reasonable maximum exposure
(RME) analysis of both adult (HQ=3.0) and adolescent receptors (HQ=3.8). Cumulative HI values for
adults and adolescents exposed to Site 6 - Impoundment Area sediment are 4.4 and 5.7, respectively,
indicating the potential for adverse noncarcinogenic health effects to occur subsequent to exposure.
Although 4-amino-2,6-DNT produces elevated HQ values, the presence of 4-amino-2,6-DNT at a single
location (6SD42), detected at a maximum concentration of 520 mg/Kg is responsible for HQ values in
excess of 1.0. No other contaminant detected in the Site 6 - Impoundment Area at any other location
produces an HQ value above 1,0.

-------
TABLE 2-1
SITE 6
SUMMARY OF HUMAN HEALTH COPCs FOR SOIL AND SEDIMENT
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
COPCs
Excavated
Area Soil
Surface Soil
(Round One)
Surface Soil
(Round Two)'"
Subsurface
Soil
Flume/
Impoundment
Area Sediment01
Tributary
Sediment
Volatile*:
1,1-Dichloroethane

1,2-Dichloroethane

1,1-Dichloroethene

X
X

cis-1,2-Dichloroethene

trans-1,2-Dichloroethene

1,2-Dichloroethene (Total)

1,1,2,2-Tetrachloroethanc

Tetrachloroethene

x
X

1,1,1-Trichloroe thane

I, i ,2-Trichloroe thane

Trichloroethene

X
X

Vinyl Chloride

X
X

SemivolatUes:
Acenaphthene

Anthracene

Benzo(a)anthracene

Benzo{a)pyrene

Benzo(b)fluoranthene

Benzo
-------
TABLE 2-1 (continued)
SITE 6
SUMMARY OF HUMAN HEALTH COPCs FOR SOIL AND SEDIMENT
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
COPCs
Excavated
Area Soil
Surface Soil
(Round One)
Surface Soil
(Round Two)'"
Subsurfac
eSoil
Flume/
Impoundment
Area Sediment(l>
Tributary
Sediment
Carbazole

Chrysene

Dibenzo(a,h) anthracene

2,4-Dinitrotoluene

2,6-Oinitrotoluene

Fluoranthene

Fluorene

lndeno(l,2,3*cd) pyrene

2-Methylnaphthalene

Naphthalene

Phenanthrene

Pyrene

Nitramines:
2-Amino-4,6-Dinitrotoluene

4-Amino-2,6-Dinitrotoluene

X
X

1,3-Dinitrobenzene

HMX

RDX

X
X

1,3,5-Trinitrobenzene

X
X

2,4,6-Trinitrotoluene

X
X

-------
TABLE 2-1 (continued)
SITE 6
SUMMARY OF HUMAN HEALTH COPCs FOR SOIL AND SEDIMENT
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
COPCs
Excavated
Area Soil
Surface Soil
(Round One)
Surface Soil
( Round Two)'"
Subsurfac
e Soil
Flume/
Impoundment
Area Sediment(l>
Tributaiy
Sediment
Inorganics:
Aluminum
X
X
X

X
X
Antimony
X

X
X
X

Arsenic
X
X
X
X
X
X
Beryllium
X
X
X
X
X
X
Cadmium
X

Chromium
X

X
X
X
Iron
X
X
X
X
X
X
Manganese

X
X
X
X
Nickel

Vanadium

X
X
Zinc
X

Notes:
Includes COPCs selected from analytical data acquired over the combined Round Two RI and Round Two Supplemental Investigation.
-------
TABLE 2-2
SITE 6
SUMMARY OF HUMAN HEALTH COPCs FOR GROUNDWATER AND SURFACE WATER
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
COPCs
Groundwater
(Dissolved)
Groundwater
(Total)
Impoundment
Area Surface
Water
(Total)
Tributary Area
Surface Water
(Total)
Volatile*:
1,1-Dichloroethane
X
X
X

1,1-Dichlorocthcne
X
X
X

cis-1,2-Dichloroethene
X
X

trans-1,2-Dichlorocthene
X
X

1,2-Dichloroethene (Total)

1,1,2,2-Tetrachloroethane

1,1 J-Trichloroethane
X
X
X
X
Trichloroethene
X
X

Semivolatiles:
Benzo(a)anthracene

Benzo(a)pyrene

Benzo(b)fluoranthene

Benzo(k)fluoranthene

Chrysene

Phenanthrene

X
•
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TABLE 2-2 (continued)
SITE 6
SUMMARY OF HUMAN HEALTH COPCs FOR GROUNDWATER AND SURFACE WATER
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
COPCs
Groundwater
(Dissolved)
Groundwater
(Total)
Impoundment
Area Surface
Water
(Total)
Tributary
Area Surface
Water
(Total)
Nitraniacs:
4-Amino-2,6-Dinitrotoluenc
X
X

HMX

RDX
X
X
X

2,4^-Trinitrotoliiene

Inorgaaks:
Aluminum
•

Antimony
X

Arsenic
X
X
X
X
Beryllium

Chromium

Iron

X
X
X
Lead

Manganese
X
X
X
X
Mercury

Nickel

Thallium
X

Vanadium

Zinc
X

-------
TABLE 2-3
INCREMENTAL LIFETIME CANCER RISK (ICR) AND HAZARD INDEX (HI)
FOR FUTURE ADULT AND CHILD ON-SITE RESIDENTS
SITE 6
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA

Pathway
Receptors'
(»
Adults
ICR
HI
Children (1-6 yrs.)
ICR
Surface Soil
rea-Round One)
[ngestion
Dermal Contact
Subtotal

5.7 x lO-06
(6.3 x 1
-------
TABLE 2-3 (Continued)
Incremental lifetime cancer risk (ICR) and hazard index (Hi)
FOR FUTURE ADULT AND CHILD ON-SITE RESIDENTS
SITE 6
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA

Receptors'"

Adults
Children (1-6 yrs.)
Pathway
ICR
HI
ICR
HI
jroundwater"'

Ingestion
1.4 x tO"06
0.02
1.6 x 10"0*
0.1
(2.4 x 104")
0.01
(7.4 x I0417)
(0.05)
bermal Contact
3.3 x 10""*
0.11
1.5 x 10**
0.19

fS.2 x 10*7>
(0.051
(5.6 x Iff")
(0.07)
Subtotal
4.7 x 10^
0.13
3,1 x I04*
0.29

(7.6 x 10417)
(0.06)
(1,3 x 10-*)
(0.12)
Surftce Water*"

Ingestion
4.2 x 10417
0.02
4.9 X 10*7
0.1

(1.5 x 10"07)
(0.02)
(4.6 X 104")
(0.01)
Dermal Contact
4.4 x I0417
0.01
2.0 x 10-"*
0.02

(1.6 x lO4")
(0.01)
(1.7 x IO*7)
(0.02)
Subtotal
8.6 x i«r°T
0.02
6.9 x IO4"
0.3

(3.1 x 10*7)
(0.03)
(6.3 x 10-")
(0-1)
Surface Watei^

(Impoundment Area)

Ingestion
2.4 x tO4*
0.07
2.9 x 10*
0.32

(5.4 x lO4')
(0.03)
(1.7 x tO4*)
(0.14)
Derma! Contact
9.5 x 104*
0.03
4.2 x Iff98
0.06

(3.3 x 104")
(0.01)
(3.6 x IO4")
(0.02)
Subtotal
9.7 x 104*
0.1
4.5 x 104*
0.31

(3.4 x I0*0*)
(0.04)
(3.8 x IO4*)
(0.16)
2-26
-------
TABLE 2-3 (Continued)
INCREMENTAL LIFETIME CANCER RISK (ICR) AND HAZARD INDEX (HI)
FOR FUTURE ADULT AND CHILD ON-SITE RESIDENTS
SITE 6
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA

Receptors'"

Adults
Children (1-6 yrs.)
Pathway
ICR
HI
ICR
HI
Sediment
fPwinaw Area)

Ingestion
1.5 x 10"06
(1.9 x 10-°')
0.02
(0.01)
3.5 x 10**
(1.2 x IC0*)
0.2
(0.07)
Dermal Contact
4.4 x 10"*
(2.2 x 10-®T)
0.05
(0-01)
1,9 x IO"06
(2.4 x I04")
0.09
(0.01)
Subtotal
5.9 x 10-°*
(4.1x10-")
0.07
(0.02)
5.4 x IO-06
(1.4 x IO"06)
0.29
(0.08)
Sediment
impoundment Area)

Ingestion
2.0 x 10"°*
(2.8 x 10"")
0.14
(0.04)
4.6 x IO4*
(1.7 x 104*)
[ I *
Dermal Contact
1.0 x IO"05
(5.7 x 10"")
l.l
(0,1)
4.6 x 10"*
(6.2 x 10*T)

Subtotal
1.2 x 10*5
(8.5 xtO"9*)
x
a.? x io^
r
I ^
Notes:
Risk values in parentheses represent central tendency (CT) estimates. Central tendency estimates reflect an
average scenario as opposed to a worst-case scenario.
111 Non-potable use of groundwater evaluated. Risk value derived using organic and dissolved inorganic
concentrations.
(,) Risk value derived using organic and total inorganic concentrations.
Shaded areas indicate exceedances of the USEPA's acceptable target risk criteria.
2-27
-------
TABLE 2-4
INCREMENTAL LIFETIME CANCER RISK (ICR) AND HAZARD INDEX (HI)
FOR CURRENT ADULT AND ADOLESCENT ON-STATION TRESPASSERS
SITE 6
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA

Receptors'"

Adults
Adolescents (7-15 yrs.)
Pathway
ICR
HI
ICR
HI
Surface Soil
(Droifaac Area-Round One)

Ingestion
1.9 x 10*'
(8.5 x 10-°*)
0.02
(0.01)
3.7 x lO"07
(1.6 x 10"°')
0.05
(0.02)
Dermal Contact
1,2 x 10"°*
(2.0 x lO"07)
0.12
(0.02)
1.4 x 10"**
(2.3 x lO"07)
0.15
(0,02)
Subtotal
1.4 x tO4*
(2.9 x lO*07)
0.14
(0.03)
1.8 x 10^
(3.9 x 104*)
0.2
(0.04)
Surface Soil
(Bo&ase Area-Round Two)

Ingestion
4 J x I0"°T
(1.5 x 10"°')
0.09
(0.03)
2.0 x lO"06
(6.9 x 15"07)
0.4
(0.13)
Dermal Contact
8.4 x 10"07
(1.1 x 10*T)
0.25
(0.03)
1.0 x 10"*
(1.3 x 10")
0.31
(0.04)
Subtotal
1.3 x 10**
(2.6 x 10^
0.34
(0.06)
3.0 x 10"06
(8.2 x lO"0*)
0.71
(0.17)
Surface Soil
(Excavated Area)

Ingestion
2.2 x I0"07
(9.3 x 10"°*)
0.05
(0.02)
4.2 x lO"0'
(1.8 x lO47)
0.1
(0,04)
Dermal Contact
8.9 X I0*T
(1.4 x 10"")
0.27
(0.04)
1.1 x Iff0*
(1.6 x 10^7)
0.34
(0.04)
Subtotal
1.1 x 10**
(2.3 x 10-")
0.32
(0.06)
1.5 x 10**
(3.4 x 10**>
0.44
(0.08)
2-28
-------
T ABLE 2-4 (Continued)
INCREMENTAL LIFETIME CANCER RISK (ICR) AND HAZARD INDEX (HI)
FOR CURRENT ADULT AND ADOLESCENT ON-STATION TRESPASSERS
SITE 6
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
p.—- t,
Receptors0'

Adults
Adolescents (7-15 yrs.)
Pathway
ICR
HI
rcR
HI
Sur\ce Water^

(BraiWe Area)

Ingestion
2.5 x 10"07
0.08
4.7 x I0*7
0.03

(2.4 x 10*7)
(0.06)
(4.5 x I0417)
(0.03)
Dermal Contact
2.6 x ID"07
0.05
3.3 x lO*7
0.06

{2.$ x 10"9T>
(0.03)
(2.8 x 10*7)
(0.04)
1
Subtotal
5.1 x 10-"
0.13
8.0 x 10*7
0.09

rt.Qx Ifr")
(OM\
<7.3 x 10*'Y
'0-071
T - -
Surface WateH2)

< Impoundment Area)

Ingestion
1.5 x 10*
025
2.8 x 10"*
0.46

(8.6 x IO
(0.1)
(1.6 x 10"*)
(0.2)
Dermal Contact
5.6x10-"
0.12
7.0 x 10*
0.14

<5.3 x I0"05)
(0.05)
(7.0 x 10*w)
(0.07)
\
Subtotal
5.8 x 10^
037
7.3 x 10*
0.6
x,—
fS4x 10^
(0.iS\
<7.2* lfl*>

Sediment

(BradfcwArea)

Ingestion
9.0 x lO"07
0,08
1.7 x I04*
0,15

(2.9 x 10-07)
(0.03)
(5.6 x 10"07)
(0.05)
Dermal Contact
2,6 x I04*
0.18
3.2 x 10-°*
0.22

(3.5 x 10")
(0.02)
(4.0 x IO*7)
(0.03)
Subtotal
3.5 x 10"°*
0,26
4.9 x 10*
0.37

f^«nn
(0.05*
<9.6x10^

2-29
-------
TABLE 2-4 (Continued)
INCREMENTAL LIFETIME CANCER RISK (ICR) AND HAZARD INDEX (HI)
FOR CURRENT ADULT AND ADOLESCENT ON-STATION TRESPASSERS
SITE 6
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
Pathway
Receptors'
:»>
Adults
ICR
Adolescents (7-15 yrs.)
ICR
Sediment
(Impoundment Area)
Ingestion
Dermal Contact
Subtotal
1.2 x 10*6
(4.5 x lO"0')
6.2 x Iff*
(1.4 x 10"°*)
7.4 x 10"°*
(1.9 x 10-°*)
22 x 1Q"04
(8.4 x lO"07)
7.7 x 10"°*
(1.6 x I0~)
9.9 x lO4*
fl.Ox 10^
Notes:
<0 Risk values in parentheses represent central tendency (CT) estimates. Central tendency estimates reflect an
average scenario as opposed to a worst-case scenario.
<2> Risk value derived using organic and total inorganic concentrations.
Shaded areas indicate exceedances of the USEPA's acceptable target risk criteria.
2-30
-------
TNT in subsurface soil produces an HQ value of 3.2 for future construction workers who may dig
throughout the Site 6 study area. The total HI for future construction workers exposed to subsurface soil is
4.4 (Table 2-5). Subsurface soil samples obtained in the vicinity of the Site 6 - Impoundment Area are
responsible for the elevated concentrations of TNT. The ICR value for future construction workers falls
within USEPA's acceptable risk range.
Sitsi
Table 2-6 presents human health COPCs evaluated for Site 7. Data presented in this section were
collected prior to the removal action conducted in 1996, but do not include qualitative data for
nitramines/nitroaromatics collected in the Site 7 - Drainage Area as part of the removal action and full
scale Pilot Study. Detailed COPC summaries are presented in Appendix A along with a comparison to
appropriate Station-wide background concentrations.
Analyses of risks to future adult and child residents exposed to Site 7 soil produce HI values of 1.2 and
4.4, respectively (Table 2-7). These elevated HI values are caused by inorganics including iron,
antimony, manganese and arsenic. Of these COPCs only iron produced HQ values greater than or equal
to 1.0. Iron was detected at a single soil sampling location in excess of Station-wide background and this
detection is responsible for the majority of the elevated HI values for both children and adults. This soil
location was situated within the Site 7 - Drainage Area and was removed in 1996. Iron does not exceed
the maximum Station-wide anthropogenic background surface soil concentration (46,400 mg/kg) at any
other sampling location. Arsenic, antimony, and manganese account for the remainder of the elevated HI
values but do not produce HQs in excess of 1.0 individually and do not affect the same target organ.
Therefore, unacceptable noncarcbiogenic health effects are not expected subsequent to surface soil
exposure at Site 7. ICR values for all media evaluated at Site 7 fall within or below USEPA's acceptable
risk range of 10"* to 10"6.
Potential current adult and adolescent trespassers exposed to environmental media at Site 7 exhibit HI
values below 1.0, indicating that adverse noncarcinogenic health effects are not expected to occur. ICR
values for all media fall below or within USEPA's acceptable risk range (Table 2-8). However,
qualitative data from the Site 7 Drainage Area indicate the presence of TNT, RDX and amino-DNTs at
concentrations that would produce both carcinogenic and noncarcinogenic human health risks subsequent
to exposure.
-------
2.6.2 Ecological Risk Assessment
The ecological risk assessment evaluates Sites 6 and 1 considering potential exposure of terrestrial and
aquatic receptors to contaminants at the sites. Table 2-9 presents the ecological contaminants of concern
(ECOCs) for both Sites 6 and 7. Appendix B presents detailed ECOC tables for both sites by medium and
a comparison to appropriate Station-wide background concentrations in similar media.
-------
TABLE 2-5
INCREMENTAL LIFETIME CANCER RISK (ICR) AND HAZARD INDEX (HI)
FOR FUTURE CONSTRUCTION WORKERS
SITES 6 AND 7
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
Pathway
Site 6"'
Construction Workers
ICR
<0.01
(<0.01)
Subsurface Soil
Accidental Ingestion
Dermal Contact
Inhalation13'
TOTAL
1.5 x 10*
(1.7 x 10-°')
8.1 x 10^
(6.7 x to-")
3,6 x iO '0
(2.5 x 10'°)
2,3 * IO"04
{9.4 x IO-07)
Notes:
(l> Risk values in parentheses represent centra! tendency (CT) estimates. Central tendency
estimates reflect an average scenario as opposed to a worst-case scenario.
«» Fugitive dusts.
Shaded areas indicate exceed&nces of the USEPA's acceptable target risk criteria.
2-32
-------
TABLE 2-6
SITE 7 AND FELGATES CREEK
SUMMARY OF HUMAN HEALTH COPCs
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
COPCs
Site 7
Shallow
Soils
Site 7
Subsurface
Soil
Site?
Groundwater
(Dissolved
Site 7
Groundwater
(Total)
Site 7
Drainage
Area Surface
Water (Total)
Felgates
Creek
Surface
Water (Total)
Site 7
Drainage
Area
Sediment
Felgates
Creek
Sediment
Volatiles:
1,1-Dichloroethane

X
X

1,1-Dichloroethene

X
X

1,1, i -T richloroe thane

X
X

Nitramines:
4-Amino-2,6-DNT

X
X
*

RDX

X
X

Inorganics:
Aluminum
X
X

X
X
Antimony
X
X
X
X

Arsenic
X
X

X
X
X
X
X
Beryllium
X
X

X
X
Cadmium
X

Chromium
X
X

X
X
Iron
X
X

X
X
X
X
X
Manganese
X
X

X
X
X
X
X
Vanadium

X
X
-------
TABLE 2-7
INCREMENTAL LIFETIME CANCER RISK (ICR) AND HAZARD INDEX (HI)
FOR FUTURE ADULT AND CHILD ON-SITE RESIDENTS
SITE 7
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA

| Receptors'"

Adults
Children (1-6 yrs.)
Pathway
ICR
Ht
ICR
HI
Surface Soil
(Studv Area)

2.3 x I0*5
(5.1 x 10*4)

Ingestion
9.7 x 10-°*
(8.1 x I0-°T)
0.3
(0.07)
1
.>•*' I

1
Dermal Contact
1.9 x 10"°'
(6.1 x IO"07)
0.93
(0.08)
8.4 x 10"*
(6.6 x IO*7)

|
Subtotal
2.9 x IO"05
{1.4 x 1Q-4*}
HI
3.1 x 10*5
(5.8 x IO*4)
ttM
Groundwater*21

Ingestion
6.0 x 10*'
(9.4 x IO4*)
0.06
(0.02)
7.0 x IO*7
(2.9 x 10*7)
0.26
(0.1)
Dermal Contact
1.3 x IO*7
(1.9 x 10"")
0.03
ro.on
5.7 x 10**
(2.1 x 10**)
0.05
(0.02)
Subtotal
7.3 x IO4"
(1.1 x 10*7)
0.09
(0.03)
7.6 x 10*7
(3.1 x 10*7)
0.31
(0.12)
Surface Water*1'
fStudy Area)

Ingestion
2.4 x Iff0'
(7.1 x 10"°*)
<0.01
(<0.01)
2.8 x IO*7
(2.2 x 10*7)
0.02
(0.01)
Dermal Contact
2.7 x 10^
(7.4 x 10**)
<0.01
(<0.01)
1.2 x 10*"
(8.1 x IO**)
<0.01
(<0.01)
Subtotal
2.7 x IO"07
(7.8 x 10**)
<0.01
(<0.01)
2.9 x IO"07
(2.3 x 10*7)
0,02
(0.01)
2-34
-------
TABLE 2-7 (Continued)
INCREMENTAL LIFETIME CANCER RISK (ICR) AND HAZARD INDEX (HI)
FOR FUTURE ADULT AND CHILD ON-SITE RESIDENTS
SITE 7
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
Pathway
Rece|
jtors"1
Adults
Children
(1-4 yrs.)
ICR
HI
ICR
HI
Sediment
(Studv Area)
Ingestion
Dermal Contact
1.3 x 10^
(2.3 x 10*T)
2.7 x 10*®*
(1.8 x lO"")
0.04
(0.02)
0.12
(0.02)
3.1 x 10^
(1.4 x I0"06)
1.2 x 10-*
(1.9 x 10"87)
0.38
(0.18)
0.2
(0.03)
Subtotal
4.0 * 16"®*
(4.1 x 10-")
0.16
(0.04)
4.3 * 10^*
(1.6 x 10^
0.58
(0.2H
Notes:
<" Risk values in parentheses represent central tendency (CT) estimates. Central tendency estimates reflect an
average scenario as opposed to a worst-case scenario.
m Non-potable use of groundwater evaluated. Risk value derived using organic and dissolved inorganic
concentrations.
Risk value derived using organic and total inorganic concentrations.
Shaded areas indicate exceedanees of die USEPA's acceptable target risk criteria.
2-35
-------
TABLE 2-8
INCREMENTAL LIFETIME CANCER RISK (ICR) AND HAZARD INDEX (HI)
FOR CURRENT ADULT AND ADOLESCENT ON-STATION TRESPASSERS
SITE 7
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA

Receptors10

Adults
Adolescents (7-15 yrs.)
Pathway
ICR
HI
ICR
HI
Surface Soil

(Study Area)

Ingestion
3.3 X 10""
0.06
6.2 x 10""
0.12

(I.I x 10-°')
(0.02)
(2.1 x 10"")
(0.04)
Dermal Contact
1.3 x ltr06
0,45
1.6 x 10"*
0.55

(i.7 % io"*)
(0.05)
(1.9 x I0"">
(0.05)
Subtotal
3.6 x 1006
0.51
2.2 x lO"04
0.67

(2 J x I0*7)
(0.0?)
(4.0 x 10"")
(0.1)
Surface Water41'

(Study Area)

Ingestion
1.4 x IQ^7
0.01
2.7 x 10""
0.02

(1.1 x 10*7)
(0.01)
(2.1 x 10^)
(0.02)
Dermal Contact
1.6 x 10"*
0.01
2.0 x 10"°*
0.01

n.2 x io"*)
(<0.01)
(1.3 x 10"*)
(<0.01)
Subtotal
1.6 x IO-07
0.02
2.9 x 10""
0.03

(7.8 x lO4")
(0.01)
(2.3 x 10"")
(<0.01)
Sediment

f Studv Area!

Ingestion
4.0 x 10""
0.07
7.6 x 10""
0.14

(1.8 x lO"01)
(0-03)
(3 J x 10^)
(0.06)
Dermal Contact
1.6 x I0"0*
0.42
2.0 x 10"*
0.52

(2.8 x 10"")
(0.07)
(3.1 x 10"")
(0.08)
Subtotal
2.0 x 10"*
0.49
2.8 x 10"*
0.66

(4.6 K I0"">
(0.1)
(6.6 x 1Q"">
(0.14)
Notes:
(l> Risk values in parentheses represent central tendency (CT) estimates. Central tendency estimates reflect an
average scenario as opposed to a worst-case scenario.
0) Risk value derived using organic and total inorganic concentrations.
Shaded areas indicate exceedances of the USEPA's acceptable target risk criteria.
2-36
-------
TABLE 2-9
ECOLOGICAL CONTAMINANTS OF CONCERN PER MEDIA
SITES 6 AND 7
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
Ecological Contaminant
of Concern
Site 6
Site 7
Felgates Creek
Impoundment Area
Flume
Area
Excavated
Area
Tributary
Ground-
Water
Surface
Soil
Surface
Water
Sediment
Ground-
Water
Surface
Water
Sediment
Surface
Soil
Surface
Water
Sediment
Sediment
Surface
Soil
Surface
Water
Sediment
Volatiles
Acetone

X
X

X
Carbon Disulfide

X
X

Chloroethane

Chloromethane

1,1-Die hloroe thane

X
X

1,2-Dichloroethane

1,2-Dichloroethene (total)

Tetrachloroethene

X
X

1,1,1-Trichloroethane

X
X

Trichloroethene

Vinyl Chloride

X
X

Semlvola tiles
Acenaphthene

X
X

Anthracene

X
X

Benzo(a)anthracene
X

X
X

Benzo(a)pyrene
X

X
X

Benzo(b)fluoranthene
X

Benzo(k)fluoranthene
X

Benzo(g.h.t)perylene
X

X
X

Bisf2-ethylhexyl)phthalate

X
X

Chrysene
Di-n-butylphthalate
X

X
X

X
2-37
-------
TABLE 2-9 (continued)
ECOLOGICAL CONTAMINANTS OF CONCERN PER MEDIA
SITES 6 AND 7
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
Ecological Contaminant
of Concern
Site 6
Site 7
Relgates Creek
Impoundment Area
Flume
Area
Excavated
Area
Tributary
Ground-
Water
Surface
Soil
Surface
Water
Sediment
Ground-
Water
Surface
Water
Sediment
Surface
Soil
Surface
Water
Sediment
Sediment
Surface
Soil
Surface
Water
Sediment
Sentivol*tiles (continued)
Dibenzo(a,h)anthracene

X
X

Fluoranthene
X

X
X

Fluoresce

X
X

lndeno< 1,2,3-cd)pyrene
X

2-Methylnaphthalene

X
X

4-Methylphenol

X
X

Naphthalene

n-Nitrosodiphelamine

Pentachlorophenol

Phenanthrene
X

X
X

Phenol

Pyrene
X

X
X

Pesticides
4,4-DDD

4,4-DDE

4,4-DDT

Nitramines
4-amino-2,6-Dinitrotoluene

X
X

2-amino-4,S-Dinitrotoluene

2,4-Dinitrotoluene

X
X

2,6-Dinitrotoluene

X
X

HMX
X
X
X
X

RDX
X
X
X
X

1,3,5-Trinitrobenzene _____

X
X

2-38
-------
TABLE 2-9 (continued)
ECOLOGICAL CONTAMINANTS OF CONCERN PER MEDIA
SITES 6 AND 7
N A VA L WEAPONS STATl ON YORKTOWN
YORKTOWN, VIRGINIA
Ecological Conlajninam
ofConcern
*
Site 6
Site 7
Petaies Creek
impoundment Area
Flume
Area
Excavated
Area
Tributary
Ground-
water
Surface
Soil
Surface
Water

Ground-
Water
Surface
Water

Surface
Soil
Surface
Water
Sediment
Sediment
Surface
Soil
Surface
W»ier
Sediment
NUnmloa (continued)
2.4,6-Trinitroioluene

X
X
X

Inorganics
Aluminum
X ,
X
X
X
X
X
X
X
X
X
X
X
X
X
Antimony
X

Arsenic

X
X

X
Beryllium
X

X
X
X

X
Cadmium

X
X
X

Chromium
X
X
X

Cobalt

X
X
X

X
X

X
X
X
X
Copper

X
X
X

X
X

Cyanide

(nut
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Lead
X
X
X
X
X

Manganese

X
X

X
X
X
X
X
X
X
X
X
Mercury
X
X
X
X

X
Nickel
X
X
X
X
X
X
X

X
X
X
X
X
X
Selenium

X
X

X
Silver

Vanadium
X

X
X
X

X
Zinc
X
X
X
X
X

X
X

X
2-39
-------
Site 6
Potential ecological risks were evaluated for both the terrestrial and aquatic environment within the Site 6
study area.
Soil samples were collected throughout the Site 6 study area. Concentrations of several soil-borne
contaminants were greater than conservative flora/fauna toxicity benchmark values or were identified by
computer models, known as terrestrial contaminant uptake models, as posing risks to animals and plants,
including: RDX, aluminum, antimony, chromium, copper, iron, lead, mercury, vanadium, and zinc. Soil
concentrations of aluminum, antimony, chromium, copper, iron, lead, mercury, vanadium, and zinc are
similar to Station-wide background surface soil concentrations. Antimony, aluminum, mercury, and zinc
exceeded background levels sporadically throughout the Site 6 - Impoundment; while zinc was detected in
12 out of 12 samples, only samples from two locations (6SO<5 and 6S15) exceeded background levels. It is
not practical to remediate soil so as to reduce contaminant concentrations below background
concentrations. Soil concentrations of RDX (detected in only one soil sample near the Site 6 - Flume
Area) exceed soil flora and fauna values, but do not produce unacceptable risks in the terrestrial models.
No action is, therefore, warranted for soil because of the presence of RDX from an ecological standpoint.
Surface water collected during the Round One RI from the Site 6 - Impoundment Area demonstrated
potential risk to aquatic receptors from concentrations of TCA, HMX, RDX, TNT, aluminum, chromium,
cobalt, copper, iron, lead, manganese, mercury, nickel, and zinc. This surface water was collected in 1991
and surface water was not present in the Site 6 - Impoundment Area during the Round Two RI. Surface
water may be influenced by groundwater which has been affected by past activities at Site 6. Remediation
of surface water as a medium is not possible because of the intermittent nature of its occurrence in the Site
6 - Impoundment Area. As such, long-term monitoring of surface water in the Site 6-Impoundment Area
has been specified as the remedial action.
-------
Sediment collected from the Site 6 - Impoundment Area demonstrated risk to benthic
macroinvertebrates/aquatic receptors from concentrations of TCA, several polynuclear aromatic
hydrocarbons (PAHs), beryllium, cadmium, chromium, iron, manganese, and nickel.
Nitramine/nitroaromatic compounds (4-amino-DNT, 2,4-DNT, 2,6-DNT, HMX, RDX, 1,3,5-
trinitroben2ene, and TNT) were detected in the sediment but were not initially evaluated because of a lack
of comparison toxicity values. Site specific toxicity data were subsequently developed from the
performance of both acute and chronic toxicity tests to provide an indication of the potential ecological
effects associated with the presence of these contaminants in sediment. Sediment concentrations of
beryllium, chromium, iron, manganese, and nickel were detected sporadically throughout the
Impoundment at concentrations exceeding background levels. Of the contaminants detected at levels
higher than background: fifty-four out of fifty-five samples showed concentrations of TCA that posed no
risk to animals or plants; only one of fifty-five samples contained a concentration of TCA that might pose a
potential risk to ecological receptors, because the concentration was greater than a risk-based screening
concentration. Computer models, known as aquatic receptor contaminant uptake models, indicated that
PAHs in sediment posed no unacceptable risks to aquatic plants or animals, however, one sediment sample
contained cadmium at a concentration greater than the Effects Range-Medium value, which indicates that
this particular sample was above the medium range of the ecological toxicity test value for cadmium.
Based on risks presented in the contaminant uptake models, site-specific toxicity data and comparisons of
sediment contaminant concentrations and background concentration levels, nitramine/nitroaromatic
compounds appear to be the primary ECOCs in the sediment collected from the Impoundment Area.
Because the removal of sediments with contaminants exceeding screening levels or background would
result in the destruction of wetland habitat, Site 6 - Impoundment Area sediment will be part of the long-
term monitoring effort.
The Site 6 - Impoundment Area is downstream from the Site 6 - Flume Area, which received discharge
from Building 109. Sediment collected in the Site 6 - Flume Area was assessed by comparing contaminant,
levels to sediment benchmark screening levels. In addition, chronic benthic toxicity tests were conducted
to determine potential effects. Nitramine/nitroaromatic compounds (4-amino-DNT; 2-amino-4,6-DNT;
2,4-DNT; 2,6-DNT; HMX; RDX; 1,3,5-TNB; and TNT) detected in the sediment were identified as
posing potential risks to the benthic macroinvertebrate community, based on the results of the site-specific
toxicity study. In addition to the nitramine compounds, the benthic community within the Site 6 - Flume
Area may also be impacted by concentrations of PCE, TCA, TCE, PAHs, beryllium, cadmium, iron, lead,
mercury; nickel, selenium and zinc.
Based on the results of previously mentioned site specific toxicity studies and the exceedence of sediment
toxicity values, chlorinated volatile organics, PAHs; nitramines/nitroaromatics, nickel and zinc are the
primary sediment ECOCs in the Site 6 • Flume Area. Sediment in the Site 6 - Flume Area is an ecological
medium of concern and will be removed and treated ex situ using a bioremediation technology. The Site
6 - Flume Area will be back-filled and revegetated to protect ecological receptors and.future human
receptors as well.
Surface water contaminants in the Tributary to Felgates Creek identified as potential risks to the aquatic
environment include: aluminum, iron, manganese, and nickel. However, site concentrations of these
inorganic ECOCs were detected below tidal freshwater background concentrations. Therefore, surface
water is not an ecological medium of concern in the tributary at Site 6 and remediating environmental
media to concentrations below background is not practical.
Sediment concentrations of phenol, beryllium, iron, and manganese pose potential risks to benthic
receptors within the Tributary at Site 6. In addition, sediment concentrations of aluminum and iron
demonstrated potential risks in the aquatic receptor models. With the exception of phenol, site sediment
-------
concentrations were also within the range of background. One detection of phenol exceeded toxicity
benchmark values, but when this detection was used in conservative uptake models, it did not result in
risks to aquatic receptors. As such, no action is necessary to protect aquatic receptors.
Site 6 - Excavated Area soil ECOCs exceeding flora/fauna toxicity benchmark values or demonstrating
risks in the terrestrial models include; aluminum, antimony, cadmium, chromium, iron, lead, vanadium,
and zinc. Aluminum, antimony, chromium, iron, lead, and vanadium in soil were detected sporadically at
concentrations above maximum Station-wide background values. Based on risks presented in the
terrestrial models and exceedences of background concentrations, aluminum, antimony, and chromium do
not produce significant ecological risks. Cadmium and zinc do produce unacceptable risks in terrestrial
models and appear to be the primary ECOCs in the soil at the Site 6 - Excavated Area. Therefore, the soil
in the Site 6 - Excavated Area will be covered to prevent contact by terrestrial ecological receptors to
affected soil.
Site 7
Potential ecological risks were evaluated in the terrestrial and aquatic environment within the Site 7 study
area and the Tributary to Felgates Creek.
The following Site 7 Soil ECOCs exceeded flora/fauna toxicity benchmark values or demonstrated risks in
the terrestrial models: aluminum, antimony, cadmium, chromium, copper, iron, lead, manganese, mercury,
vanadium, and zinc. Aluminum, antimony, chromium, iron, manganese, and vanadium were detected
sporadically at concentrations exceeding the maximum Station-wide background level for surface soil.
The contaminants generating potential ecological risk in modeling and exceeding background
concentrations include: cadmium, copper, lead, mercury, and zino. The maximum detections of these five
inorganics were found in one soil sample collected from sample location 7S09. The soil at this sample
location was excavated and removed from the Site 7 - Drainage Area along with sediment in the drainage
ditch during the full-scale Pilot Study. These inorganics arc no longer potential ECOCs for Site 7. No
additional action beyond the removal action for the purposes of the full-scale Pilot Study, which has
already been conducted, is necessary to protect ecological receptors at Site 7.
Surface water ECOCs identified in the tributary at Site 7 include aluminum, iron, manganese, and nickel.
Concentrations of these inorganic surface water ECOCs were detected within tidal freshwater background
ranges. Remediation of environmental media to concentrations below Station background is not practical
and no action is warranted.
Sediment collected from the Site 7 tributary poses potential risks to benthic macroinvertebrates or aquatic
receptors because of detected concentrations of di-n-butylphthalate, aluminum, beryllium, iron, and
manganese. Sediment concentrations of aluminum, beryllium, iron, and manganese were detected within
the range of background sediment concentrations. Only one of six detections of di-n-butylphthalate
exceeded a published toxicity benchmark value; however, this concentration did not produce unacceptable
HQ values in conservative uptake modeling. Therefore, no action is necessary to protect aquatic ecological
receptors.
2.6 J Summary of Risk Assessment Results
Table 2-10 presents remediation levels (RLs) for contaminants detected in Site 6 soil and sediment. These
contaminants are those chemicals responsible for unacceptable human health risks or ecological effects
described previously. These RLs were derived by selecting the lowest and most protective of two possible
-------
RLs, one for human health and one for the ecological receptors. The following paragraphs present a
summary of findings of the baseline RA-
TABLE 2-10
SUMMARY OF REMEDIATION LEVEL (RL) VALUES FOR
SITE 6 SEDIMENT AND SOIL WPNSTA YORKTOWN, YORKTOWN, VIRGINIA
Medium/Chemical of Concern
RL Value
(mg/kg)
RL Value J
Source
Treatment*61
Goals (mg/kg)
SEDIMENT

Trichloroethene
1.6
Ecological(,)
32
1,2-Dichloroethene(total)
3.5
Ecological0'
700
Tetrachloroethene
31
Human®
7
1,1 -Dichloroethane
200,000
Human*1'
6,500
1,1,1 -T richloroethane
70,500
Human*2'
2,700
Carcinogenic Polycyclic
Aromatic Hydrocarbons
(PAHs)
10
Human®
10
total PAHs
44
Ecological10
44
amino-DNTs
10
Human'3'
10
2,4-dinitrotoluenc
60
Humana)
60
2,6-dinitrotoluene
29
Human3'
29
HMX
5.7
Ecological53'
5.7
RDX
5.0
Human'25
5.0
1,3,5-TNB
1.6
Ecological**'
1.6
2,4,6-TNT
14.0
Human*1'
14.0
Cadmium
9.6
Ecological0'
9.6
Nickel
52
Ecological0'
52
Zinc
410
Ecological0'
410
SOIL

Cadmium
4.0
Ecological*4'
4.0
Zinc
48,4
Background*s>
| 48.4
Notes:
l" Effects Range Median (ER-M) value.
m Based on future commercial property use scenario.
<5) Derived from site specific toxicity testing.
(4) Will and Suter value for flora toxicity.
(3) Maximum detected Station-wide surface soil background value.
(5) Treatment Goals differ for F002 listed waste constituents.
* Considers a scenario for all carcinogenic polycyclic aromatic hydrocarbons as benzo(a)pyrene
where risk of concern increases by one cancer case in 100,000.
-------
s;tr ff - Ftlime Area
The presence of nitramines/nitroaromatics and chlorinated volatile compounds in Site 6 - Flume Area
sediment produced unacceptable risks to human health and aquatic ecological receptors. Elevated
concentrations of contaminants were detected in samples obtained from the Site 6 - Flume Area during
acute and chronic toxicity testing to develop site-specific toxicity values. Concentrations encountered in
Site 6 - Flume Area sediments exceeded human health-based RL values and caused increased mortality in
benthic organisms tested during the chronic toxicity testing. To protect both human health and the
environment. Site 6 - Flume Area sediment contaminated with nitramines/nitroaromatics (amino-DNTs,
2,4/2,6-DNT, TNT, HMX, RDX, and 1,3,5-TNB), PAHs, chlorinated volatiles, and inorganics will be
excavated and treated ex situ using-a bioremediation technology. Residual contamination will remain at the
site after excavation and treatment, however, that will make the site inappropriate for residential uses.
Consequently, residential use will be prohibited as part of the remedy.
Site 6 - Impoundment Area
Surface water and sediment of the Site 6 - Impoundment Area have also been affected by past activities at
Site 6, posing potential adverse affects on aquatic ecological receptors. The compound 4-amino-2,6-DNT
detected at the 12-inch depth interval in one sample could pose unacceptable systemic human health risks
to exposed trespassing adolescents and adults. Nitramines, chlorinated volatiles and inorganics including
nickel and zinc detected throughout the Site 6 - Impoundment may be responsible for unacceptable .
ecological risks, including exceedences of flora/fauna toxicity values and ecological HQ values exceeding
1.0. Unlike the Site 6 - Flume Area, contaminants occur sporadically throughout the impoundment and at
depth. Remediation of the area could cause greater harm to ecological receptors than no action, and
additional data are necessary to determine the potential ecological impacts associated with these
contaminants. Therefore the selected remedy will include long-term monitoring of Site 6 - Impoundment
Area surface water, sediment, and groundwater to determine if more aggressive remediation is necessary
to protect the environment.
Site 6 - Excavated Area
Surface soil in the Site 6-Excavated Area is contaminated with inorganics including cadmium and zinc
that pose unacceptable risks to terrestrial ecological receptors. This area is relatively small. Re grading
the area, adding soil cover, and revegetating the area will protect terrestrial ecological receptors from
exposure to soil contaminants.
Siic.J ~ Drsins^c
Environmental media investigated at the Site 7 - Drainage Area posed no unacceptable human health or
ecological risks under any land use scenario. However, qualitative data for TNT, RDX and amino-DNTs
generated as part of the full-scale Pilot Study indicate that carcinogenic and noncarcinogenic human
health risks would occur in this area subsequent to exposure. Excavation of contaminated soil and
sediment for die full-scale Pilot Study in 1996 removed contaminants that posed potential risks to both
human health and the environment and no additional action at this site is necessary. However, a landuse
restriction will be implemented to prohibit future residential use of the area because soil and sediment
were removed to protect individuals exposed under commercial/industrial land use scenarios and not
residential property use.
-------
2.7 Inscription of jft.f Alternatives for Sit*, (f
The DoN considered a range of potential remedial action alternatives (RAAs) for the remediation of
contaminated soil and sediment at Site 6, Each of the action alternatives (Alternatives 2 through 6)
requires that the residue be removed front the trenches under Building 109 and pressure washed. Each of
the "treatment" alternatives (Alternatives 3 through 6) requires that the sediment in the Site 6 * Flume Area
be treated in situ or ex situ. The following alternatives were evaluated:
• Alternative I
• Alternative 2
• Alternatives
• Alternative 4
• Alternative 5
• Alternative 6
2.7.1 Alternative 1: No Action
No Action
Monitoring and Residue Removal from Building 109
In Situ Biological Treatment, Soil Cover, and Residue Removal
from Building 109.
Ex Situ Biological Treatment, Limited Excavation and Off-Site
Disposal, aid Residue Removal from Building 109
Excavation with Off-Site Incineration and Residue
Removal from Building 109
Ex Situ Biological Treatment, Soil Cover, Limited Excavation,
and Residue Removal from Building 109
This alternative involves no remedial action to contain, remove, or treat contaminants in Site 6
soil/sediment. It is not protective of human health or the environment. There are no Applicable or
Relevant and Appropriate Requirements of federal or state law (ARARs) for this alternative, ft was,
however, evaluated to provide a baseline for comparison to other remedial alternatives.
• Estimated Capital Cost: SO
• Estimated Operation and Maintenance (O&M) Costs: 10
• Estimated Present Worth Cost: $0
• Estimated Time to Implement: Immediate
2.7.2 Alternative 2: Monitoring and Residue Removal
This alternative does not involve actions to contain, remove, or treat Site 6 soil/sediment contaminants, but
does provide for long term monitoring of Impoundment Area sediment which would provide data to be
used to assess the potential impact to human health and the environment. Long-term monitoring would
also indicate if contaminant concentrations in sediment are decreasing. Numerous studies have shown that
indigenous microbes can metabolize TNT. TNT in surficial water or soil can also be broken down by
strong sunlight (ultraviolet radiation). Finally, plants have been shown to decrease concentrations of
explosives in soil and groundwater through several processes including: enhanced biodegradation, phyto-
extraction (phyto-accumulation), phyto-degradation, and phyto-stabilization. These processes cither
remove, transfer, stabilize, or destroy the contaminants. Wetland plants, such as cattails, canary grass,
milfoil, and parrotfeather are being studied because they contain an enzyme called nitroreductase which,
with other plant enzymes, can degrade TNT, RDX, and HMX. Chlorinated volatile compounds can be
degraded in the soil zone where plant roots grow.
-------
This alternative provides some protection of human health and the environment through the removal of
residue from the trenches of Building 109 (considered a potential secondary source of contamination). The
residue will be removed and the trenches pressure washed. The residue will be transported to an on-site,
permitted burning area for proper disposal. Wastewater from the pressure washing will be collected and
safely disposed.
Since contaminated soil/sediment would remain on site under RAA 2 and will continue to be a source of
contamination, annual sediment monitoring will be conducted to assess the potential, ongoing impact to
human health and the environment. Two sediment samples will be collected annually at the Site 6 - Flume
Area and will be analyzed for VOCs and explosives. No fewer than six sediment samples will be
collected annually at the Site 6 - Impoundment Area and analyzed for VOCs, SVOCs, explosives, and
inorganics. The details of the monitoring program will be addressed in the LTM Work Plan.
Implementation of this alternative would require compliance with location- and action-specific ARARs
because wetlands and possibly archeoSogical resources are present at the site. No chemical-specific
ARARs have been established for the soil/sediment contaminants of concern (COCs).
Estimated Capital Cost: $S7,700
Estimated O&M Costs: $11,800
Estimated Present Worth Cost: $239,000
Estimate to Implement:
This alternative can be implemented in a period of
weeks, assuming remedial action work plans and long-
term monitoring plans are completed. No design is
necessary for this alternative. Sediment sampling can
begin immediately after the approval of the LTM Work
Plan and the pressure washing of Building 109 trenches
can be completed in several weeks. A LUCIP will be
submitted within 180 days following residue removal and
disposal.
2.7J Alternative 3: In Situ Biological Treatment, Soil Cover, and Residue Removal
In situ biological treatment would be used to treat approximately 1,000 cubic yards of contaminated soil
and sediment from the Site 6-Flume Area. The affected area will be tilled every two weeks to mix in the
additives and control the soil conditions to alternate between aerobic and anaerobic conditions. Indigenous
microbe growth will be enhanced. The additives will bulk the soil and sediment by approximately 10
percent No active remediation will occur at the Site ^Impoundment Area to prevent extensive
disturbance to the marshy area. Long-term monitoring, as described under RAA 2, will be conducted to
assess the potential ongoing impact to human health and the environment. At the Site 6-Excavated Area,
the cadmium- and zinc-contaminated soil will remain in place and a soil cover will be installed. The soil
cover will consist of a minimum of S inches of soilflll to prevent erosion. Residue will be removed from
the trenches under Building 109, as described under RAA 2. Operation and maintenance (O&M) will
entail maintenance of the Site 6 - Excavated Area soil cover. Long-term monitoring of surface water,
sediment, and groundwater will be implemented as part of this remedy. Details of long-term monitoring
will be developed in consultation with USEPA Region III and VDEQ personnel.
-------
Tie remedy for the Site 6 - Flume Area and the L996 removal action at Site 7 are designed to reduce
contamination to levels that will be safe for people engaged in typical commercial or industrial activities.
Land use controls will be established to prevent residential exposure to the contaminants remaining at Site
7 and the Site 6 - Flume Area, Land use controls will also be established to prohibit activities that interfere
with or compromise the integrity of the cover at the Site 6 - Excavated Area.
Some earth moving activities are involved with this alternative. Implementation will require compliance
with location-specific ARARs because wetlands, and possibly archeological resources, are present at the
site. Action-specific ARARs associated with the identification, regulation, production, and disposal of
solid wastes will apply. No chemical-specific ARARs have been established for the soil/sediment COCs.
• Estimated Capital Cost 5393,000
• Estimated O&M Costs: $11,000
• Estimated Present Worth Cose 5566,700
» Estimated Time to Implement:
Assuming that all work plans and long-term monitoring
plans are completed, this alternative can be implemented
within approximately 6 to 9 months. The installation of
the soil cover should be completed within six months.
Treatment of thesoil/sediment may be completed within
three to nine months. Sediment monitoring can begin
immediately,
2.7.4 Alternative 4: Ex Situ Biological Treatment, Limited Excavation and Off-Site Disposal, and
Residue Removal
Alternative 4 involves removing approximately 1,000 cubic yards of contaminated soil and sediment from
the Site 6 - Flume Area and transporting it to die existing aqueous phase biocell at Site 22 for ex situ
biological treatment. Treated soil/sediment will be used as backfill at the Station, No active remediation
will be done at the Site 6 - Impoundment Area in order to prevent disturbance to the marshy area and
destruction of existing habitat Approximately 500 cubic yards of cadmium and zinc contaminated surface
soil at the Site 6 - Excavated Area will be excavated and loaded onto trucks for off-site disposal.
Confirmatory sampling will be conducted to ensure that the inorganic COCs are removed from the site.
The Site 6 - Excavated Area will then be backfilled and covered with topsoil for revegetation. Residue
will be removed from the trenches under Building 109 as described under RAA 2.
Because earth moving activities are involved for this alternative, location-specific ARARs apply because
wetland, and possibly archeological resources, are present at the site. Action-specific ARARs associated
with the identification, regulation, production, and disposal of solid wastes and hazardous wastes will
apply, No chemical-specific ARARs have been established for the soil/sediment COCs.
Long-term monitoring of surface water, sediment and groundwater will be implemented as part of this
remedy. Details of long-term monitoring will be developed in consultation with USEPA Region III and
VDEQ personnel.
The remedy for the Site 6 - Flume Area, and the 1996 removal action at Site 7, is designed to reduce
contamination to levels that will be safe for people engaged in typical commercial or industrial activities.
Land use controls will be established to prevent residential exposure to the contaminants remaining at Site .
7 and the Site 6 - Flume Area.
-------
• Estimated Capital Cost; $426,000
• Estimated O&M Costs: $10,800
• Estimated Present Worth Cost: $592,000
• Estimated Time to Implement-
Assuming that all work plans and long-term monitoring
plans are completed, this alternative can be implemented
within approximately nine months. The organic-
contaminated soil can be excavated and placed in the
biocell within approximately three months. Treatment of
the soil may be completed within three to nine months.
2.7.5 Alternative 5: Excavation with Off-Site Thermal Treatment and Residue Removal
This alternative involves excavation of approximately 1,500 cubic yards of contaminated soil and sediment
from the Site 6-Flume Area and the Site 6 - Excavated Area. The organic-contaminated soil/sediment
excavated from the Site 6 - Flume Area will be transported off-site for incineration. The inorganic-
contaminated surface soil excavated from the Site 6 - Excavated Area will be transported off-site for
disposal. Confirmation sampling will be conducted to verify that soil and sediment with COC
concentrations exceeding the final RLs have been removed. Both of the disturbed areas will be backfilled
with clean fill and topsoil for revegetation. No active remediation will be done at the Site 6 *
Impoundment Area to prevent extensive disturbance of the marshy area and destruction of existing habitat.
However, long-term sediment monitoring, as described under previous RAAs, will be conducted to assess
the Site 6-Impoundment Area. Residue will be removed from the trenches under Building 109 as
described under RAA 2,
Because earth moving activities are involved with this alternative, location-specific ARARs apply because
wetlands, and possibly archeological resources, are present at the site. Action-specific ARARs associated
with the identification, regulation, production, and disposal of solid wastes and hazardous wastes will
apply.
Long-term monitoring of surface water, sediment, and groundwater will be implemented as part of this
remedy. Details of long-term monitoring will be developed in consultation with USEPA Region III and
VDEQ personnel.
The remedy for the Site 6 - Flume Area, and the 1996 removal action at Site 7, are designed to reduce
contamination to levels that will be safe for people engaged in typical commercial or industrial activities.
Land use controls will be established to prevent residential exposure to the contaminants remaining at Site
7 and the Site 6 - Flume Area.
In the proposed plan, Remedial Alternative 5 included described two different treatment technologies:
off-site incineration of contaminated soil and sediment (Alternative 5a) and on-site low temperature
thermal desorption (LTTD) (Alternative 5b). After the proposed plan was issued, it was determined that
the LTTD could not be used to treat the levels of nitramine/nitroaromatic contamination at Site 6.
Consequently, in this ROD, Alternative 5 does not include a description of LTTD.
• Estimated Capital Cost: $791,000
• Estimated O&M Costs: $10,800
• Estimated Present Worth Cost: $957,000
• Estimated Time to Implement:
-------
This alternative can be implemented within
approximately three to six months assuming that an off-
site incineration facility and off-site landfill facility are
available, and all work plans are completed. Sediment
monitoring can begin immediately assuming all
monitoring plans are completed.
2.7.6 Alternative 6: Limited Excavation, Ex Situ Biological Treatment, Soil Cover, Residue
Removal
Alternative 6 consists of excavating approximately 1,000 cubic yards of contaminated soil and sediment at
the Site 6-Flume Area and treating it on-site with an ex situ bioremediation process. The same process as
described for Alternative 3 will be used for this treatment with the exception that the soil and sediment will
be excavated, placed, and treated at a staging area instead of being treated in place. If the bioremediation
process is not able to reduce concentrations of chlorinated volatile organics in the soil to remediation levels
specified in table 2-10, low temperature thermal treatment will be employed to reduce chlorinated volatile
organic concentrations to remediation levels specified in Table 2-10. To prevent extensive disturbance to
the marshy area at the Site 6-Impoundment Area, no active remediation will be performed. However,
long-term sediment, surface water, and groundwater monitoring will be conducted to assess conditions in
the Impoundment Area. The monitoring program would be similar to that described under RAA 2, except
that area groundwater and Impoundment Area surface water would also be monitored. A soil cover will be
installed at the Site 6-Excavated Area as described in Alternative 3. Residue will be removed from the
trenches under Building 109 as described under RAA 2.
Location-specific ARARs apply because wetlands, and possibly archeological resources, are present at the
site. Action-specific ARARs associated with the identification, regulation, production, and disposal of
solid wastes and hazardous wastes will apply. No chemical-specific ARARs have been established for the
sediment/soil COCs,
Long-term monitoring of surface water, sediment, and groundwater will be implemented as part of this
remedy. Details of long-term monitoring will be developed in consultation with USEPA Region III and
VDEQ personnel.
The remedy for the Site 6 - Flume Area, and the 1996 removal action at Site 7, are designed to reduce
contamination to levels that will be safe for people engaged in typical commercial or industrial activities.
Land use controls will be established to prevent residential exposure to the contaminants remaining at Site
7 and the Site 6 - Flume Area. Land use controls will also be established to prohibit activities that interfere
with or compromise the integrity of the cover at the Site 6 - Excavated Area.
• Estimated Capital Cost 1461,000
• Estimated O&M Costs: $20,200
• Estimated Present Worth Cost: $771,500
• Estimated Time to Implement:
This alternative can be completed within approximately
six months to a year. The installation of the soil cover
should be completed within six months. The sediment,
groundwater, and surface water monitoring can begin
immediately. Excavation of organic-contaminated
soil/sediment can be completed within approximately
three months. Treatment of the soil/sediment may be
completed within three to nine months.
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2.8 Evaluation of Alternative
As required by CERCLA, the si* remedial alternatives were evaluated using the nine criteria specified by
USEPA (Table 2-11). This section and Table 2-12 summarize the detailed analysis of each alternative.
As part of the FS process, each of the RAAs was assessed against nine evaluation criteria which fall into
three categories: threshold criteria, primary balancing criteria, and modifying criteria. The threshold
criteria must be met for an alternative to be eligible for selection. The primary balancing criteria are used
to weigh major trade-offs among alternatives. Generally, the modifying criteria are taken into account after
public comment is received on the PRAP. The nine evaluation criteria include:
Threshold Criteria
• Overall Protection of Human Health and the Environment
• Compliance with ARARs
Primary Balancing Criteria
• Long-Term Effectiveness and Permanence
• Reduction of Toxicity, Mobility, or Volume Through Treatment
• Short-Term Effectiveness
• Implementability
• Cost
Modifyinj Cntcns
• State Acceptance
• Community Acceptance
-------

TABLE 2-11

USEPA EVALUATION CRITERIA FOR REMEDIAL ALTERNATIVES
SITE 6
WPNSTA YORKTOWN, YORKTOWN, VIRGINIA
1.
Overall protection of human health and the environment
Addresses whether a cleanup method adequately protects human health and the environment
and describes how risks presented by each pathway are eliminated, reduced, or controlled
through treatment, engineering controls, or institutional controls.
2.
Compliance with ARARs
Addresses whether a cleanup method meets all ARARs (federal and state environmental
requirements) and provides grounds for invoking a waiver.
3.
Long-term effectiveness and permanence
Refers to the ability of the cleanup method to reliably protect human health and the
environment over time, after the action is completed.
4.
Reduction of toxicity, mobility, or volume through treatment
Addresses the effectiveness of a cleanup method in reducing the toxicity, mobility, or volume
of hazardous substances through treatment.
5.
Short-term effectiveness
Addresses the period of time needed to complete the cleanup, and any adverse impacts on
human health and the environment that may occur during construction and operation.
6.
Implementability
Refers to the technical and administrative feasibility of a cleanup method, including the
availability of required materials and services.
7.
Cost
Includes the estimated capital and O&M costs of each cleanup method.
8.
State acceptance
Indicates whether the Commonwealth of Virginia agrees with the preferred cleanup method.
9.
Community acceptance
Indicates whether public concerns are addressed by the cleanup method and whether the
community has a preference. (Public comment is an important part of the final decision.)
2-54
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TABLE 2-12
SUMMARY OF DETAILED ANALYSIS
SITE 6
WPNSTA YORKTOWN, YORKTOWN, VIRGINIA
Evaluation
RAA 1: No Action
RAA 2: No Action with
Monitoring and Sludge
Removal
RAA 3: In Situ Biological
Treatment, Soil Cover, and
Sludge Removal
RAA 4: Ex Situ Biological
Treatment, Limited Excavation
and OfT-Site Disposal
RAA 5: Excavation with
Off-Site Incineration and
RAA 6: Ex Situ Biological Treatment,
Soil Cover, Limited Excavation, and
Overall Protectiveness
• No reduction in risk
to human health or
the environment.
• Existing conditions
could allow migration
of contaminants off-
site.
• Removes potential source
of contamination to other
environmental media
(sewer sludge).
• Direct exposure to
contaminated soils and
sediments is not reduced.
• Monitors quality of
sediment.
• Significant reduction in risk
by treatment of sediments,
capping of soils, removal of
sludge.
• Capping prevents erosion
and percolation reducing
migration of contaminants.
• Monitors quality of
sediment.
• Significant reduction in risk
by treatment and removal of
sediments, soils, and sludge.
• Monitors quality of
sediment.
* Significant reduction in
risk by treatment and
removal of sediments,
soils, and sludge.
• Monitors quality of
sediment.
• Significant reduction in risk b>
treatment and removal of sediments,
soils, and sludge.
> Capping prevents erosion and
percolation reducing migration of
contaminants.
* Monitors quality of sediment, surface
water, and groundwater.
Compliance with ARARs
No ARARs.
Will meet ARAJts.
Will meet ARARs.
Will meet ARARs.
Will meet ARARs.
Will meet ARARs.
Long-Term Effectiveness
and Performance
• Unknown
• Removal of sludge will
permanently reduce risk.
• Sediment monitoring will
indicate if remedial action
is required in the
Impoundment Area.
• Soil/sediment treatment and
sludge removal will
permanently reduce risk.
• If cap is maintained, will be
effective.
• Sediment monitoring will
indicate if remedial action is
required in the
Impoundment Area.
• Soil/sediment treatment and
sludge removal will
permanently reduce risk.
• Sediment monitoring will
indicate if remedial action is
required in the
Impoundment Area.
• Soil/sediment removal
will be an effective and
permanent option.
• Sediment monitoring will
indicate If remedial action
is required in the
Impoundment Area.
* Soil/sediment removal will be an
effective and permanent option.
* If cap is maintained, will be effective
and permanent at reducing exposure.
* Sediment monitoring will indicate if
remedial action is required in the
Impoundment Area.
Reduction of Toxicity,
Mobility, or Volume
Through Treatment
• Will not treat
contaminants.
• Will not treat
contaminants.
• Soil/sediment COCs will be
treated by biological
methods to reduce toxicity.
• Soil/sediment COCs will be
treated by biological
methods to reduce toxicity.
• Soil/sediment COCs will
be treated by thermal
methods to reduce
toxicity and volume.
• Soil/sediment COCs will be treated
by biological methods to reduce
toxicity. A contingent technology
such as low temperature thetmal
desoiption may be employed to
reduce volatile to health based levels.
Short-Term Effectiveness
• Risk to community
not increased.
• No significant risk to
workers.
• Risk to community not
increased.
• Increased risk to workers
during sludge removal.
• Risk to community may
increase due to fugitive dust
from earth moving activities.
• Increased risk to workers
during soil treatment
activities and cap
installation.
• Risk to community may
increase due to fugitive dust
from earth moving activities.
• Increased risk to workers
during soil treatment and
removal activities.
• Risk to community may
increase due to fugitive
dust from earth moving
activities.
• Increased risk to workers
during soil removal
activities.
• Risk to community may increase due
to fugitive dust from earth moving
activities.
• Increased risk to woiieis during soil
removal, treatment activities and cap
installation.
Implementability
Costs (NPW)
• No construction
operation activities
planned.
• No monitoring
proposed.
$0.00
• Monitoring and sludge
removal activities easily
implemented.
• Equipment and materials
readily available.
$250,000
• Monitoring, sludge removal,
capping and treatment
activities easily
implemented.
• Equipment and materials
readily available,
$539,000
• Monitoring, sludge removal
and treatment activities
easily implemented.
• Equipment, materials and
biocell readily available.
• Permitting required for soil
disposal.
$620,000
• Monitoring, sludge
removal and excavation
activities easily
implemented.
• Equipment and materials
readily available.
• Permitting required for
soil disposal and off-site
incineration facilities.
$1,058,000
• Monitoring, sludge removal, capping
and treatment activities easily
implemented.
• Equipment and materials readily
available.
• Permitting possibly required Tor
sediment disposal.
$652,000
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2.8.1 Threshold Criteria
Overall Protection of Human Health and the Environment:
Evaluation of the overall protectiveness of alternatives focused on whether a specific alternative would
achieve adequate protection of human health and the environment and how risks posed by each pathway
would be eliminated, reduced, or controlled through treatment, engineering, or institutional land use
controls. The overall assessment of the level of protection included the evaluations conducted under other
criteria, especially long-term effectiveness and permanence, short-term effectiveness, and compliance with
ARARs,
Alternative 6 provides the greatest extent of protection to human health and the environment since it
provides source control by removing and treating the primary source of contamination at Site 6 - Flume
Area and removes a potential secondary source of contamination (the sludge within Building 109
trenches). The No Action Alternative (Alternative I) does not reduce potential risks to human health or
the environment (except through natural attenuation). Because the no action alternative does not meet
threshhold criterion of protecting human health and the environment, itwill not be analyzed further.
Alternative 2 will provide some overall protection with the removal of the potential secondary source of
contamination (residue under Building 109), but wilt not comply with soil and sediment RLs at the Site 6 -
Flume Area and Site 6-Excavated Area. Alternatives 3 and 4 provide slightly less protection to human
health and the environment than Alternative 6. Alternative 3 employs in situ biological treatment and may
not adequately reduce contaminants to any appreciable extent with depth. Alternative 4 would consider
the use of the existing biocell at Site 22 to remediate nitramines/nitroaromatics in soil and sediment.
Treatment at the biocell may not reduce concentrations of chlorinated volatile organics. Alternative S
would be as protective as Alternative 6. None of the alternatives will meet the sediment RLs established
for organics at the Site 6 - Impoundment Area except possibly by natural attenuation processes. Sediment
will not be removed or treated in order to protect existing habitat.
-------
Compliance with ARARs?
This evaluation involved determining whether each alternative would meet all of the pertinent Federal and
state ARARs (as identified in Section 2.11.2 of this report).
Each alternative was evaluated for compliance with applicable or relevant and appropriate Federal and
state requirements. The evaluation summarized which requirements are applicable or relevant and
appropriate to each alternative. The following items were considered for each alternative;
• Compliance with chemical-specific ARARs (e.g., ambient water quality criteria). This factor
addresses whether die ARARs can be met, and, if not, whether a waiver may be appropriate.
• Compliance with location-specific ARARs (e.g., preservation of historic sites, regulations
relative to activities near wetlands or floodplains, etc.). As with other ARAR-related factors,
these involve consideration of whether the ARARs can be met or whether a waiver is
appropriate.
• Compliance with action-specific ARARs (e.g., RCRA minimum technology standards). It must
be determined whether ARARs can be met or must be waived.
No chemical specific ARARs apply to the remediation of Site 6. Alternatives 2, 3,4, 5, and 6 will comply
with all location-specific and action-specific ARARs.
2.8.2 Primary Balancing Criteria
Long-term Effectiveness and Permanence:
This criterion evaluated alternatives with respect to their long-term effectiveness and the degree of
permanence. The primary focus of this evaluation was the residual risk that will remain at the sites and the
effectiveness of the controls that will be applied to manage residual risks. The assessment of long-term
effectiveness was made considering the following four factors:
• The magnitude of the residual risk to human and environmental receptors remaining from
untreated waste or treatment residues at the completion of remedial activities.
• An assessment of the type, degree, and adequacy of long-term management (including
engineering controls, institutional controls, monitoring, and operation and maintenance)
required for untreated waste or treatment residues remaining at the site.
• An assessment of the long-term reliability of engineering and/or institutional controls to provide
continued protection from untreated waste or treatment residues.
• The potential need for replacement of the remedy and the continuing need for repairs to
maintain the performance of the remedy.
Alternative 2 does not include removal of soil or sediment but does include removal of the Building 109
residue. It is not effective in reducing risk to ecological receptors. Alternative 3 is permanent, but its
long-term effectiveness is dependent on the ability to degrade contaminants in situ at the Site 6 - Flume
Area and future cover maintenance at the Site 6 - Excavated Area. Alternative 4 would likely not be
effective because treatment at the Site 22 biocell would not reduce concentrations of volatile organics.
-------
Alternative 5 is permanent because the contaminated soil and sediment from the Site 6 - Flume Area and
soil from the Site 6 - Excavated Area will be removed and treated using a permitted off-site incineration
facility. Alternative 6 is also permanent because the contaminated soil and sediment in the Site 6 - Flume
Area will be removed and biologically treated. However, long-term effectiveness for the Site 6 -
Excavated Area is a function of ongoing soil cover maintenance by Station personnel. None of the
alternatives are permanent with regard to the organic contamination in the Site 6 - Impoundment Area
because the sediment will not be removed to protect existing habitat. Long-term monitoring at the Site 6 -
Impoundment Area will assess area groundwater and Impoundment Area surfacewater/sediment quality for
all of the alternatives except for Alternative I (No Action). If degradation of groundwater, surface water,
and sediment quality is observed, remedial action at the Site 6 - Impoundment Area may be evaluated.
Natural attenuation may occur at the Site 6 - Impoundment Area because the contaminants are organic.
This occurrence will be detected through the long-term monitoring program.
Reduction of Toxicity. Mobility, or Volume Through Treatment:
This evaluation criterion addressed the degree to which the alternatives employ treatment technologies that
permanently and significantly reduce toxicity, mobility, or volume of the hazardous substances.
Alternatives that do not employ treatment technologies do not reduce toxicity, mobility, or volume of
COCs. The evaluation considered the following specific factors:
• The treatment processes, the remedies that will be employed, and the materials that will be
treated.
• The amount or volume of hazardous materials that will be destroyed or treated.
• The degree of expected reduction in toxicity, mobility, or volume, including how the principal
threat is addressed through treatment.
• The degree to which the treatment will be irreversible.
• The type and quantity of treatment residuals that will remain following treatment.
Alternative 2 does not employ treatment technologies which reduce toxicity, mobility, or volume.
Alternative 3 may reduce the toxicity of the organic-contaminated soil in the Site 6-Flume Area through
biological treatment depending on the efficacy of the in situ treatment process with respect to
contamination at depth. The process is irreversible and will reduce contaminant concentrations below the
established RLs. Alternative 4 utilizes in situ biological treatment to destroy explosives and other organic
contaminants and produces relatively non-toxic intermediates. It may not, however, reduce toxicity,
mobility or volume of volatile organics in contaminated soil and sediment. Alternatives 5 and 6 do reduce
toxicity, mobility, and volume of waste at the site. Alternatives 5 and 6 are also irreversible and will
reduce contaminant concentrations to below the established RLs. There will be residual contamination
associated with Alternative 5 (residual ash) that will be disposed of by the vendor responsible for off-site
treatment by incineration. There will be no residual waste associated with Alternative 6 (other than
investigation derived waste [IDW]).
-------
Short-Term Effectiveness:
The short-term effectiveness of each alternative was evaluated for its effect on human health and the
environment during implementation of the remedial action. Potential threats to human health and the
environment associated with handling, treatment, or transportation of hazardous substances were
considered. The short-term effectiveness assessment was based on four key factors:
• Short-term risks that might be posed to the community during implementation of an alternative.
• Potential impacts on workers during remedial action and the effectiveness and reliability of
protective measures.
• Potential environmental impacts of the remedial action and the effectiveness and reliability of
mitigative measures during implementation.
• Time until remedial response objectives are achieved.
Although excavation and sludge removal activities could potentially expose workers to contamination
during implementation of Alternatives 3, 4, 5, and 6, these alternatives are protective of human health and
the environment in the short-term and could be completed within one year after implementation.
Alternative 2 is less protective of human health and the environment in the short term compared to the
other alternatives because the contaminated soil and sediment will remain in place. Of these alternatives,
Alternative 2 could be implemented most quickly (several weeks). Excavation activities for Alternatives 3,
4, 5, and 6 could be implemented in approximately three months. However, for Alternative 3 and 6 involve
earth moving activities for the soil cover placement could take six months to implement
Implementabilitv.
Implementability considerations included the technical and administrative feasibility of each alternative
and the availability of various materials and services required for its implementation. The following factors
were considered during the implementability analysis;
• Technical Feasibility'. The relative ease of implementing or completing an action based on
site-specific constraints, including the use of established technologies, such as:
*¦ Ability to construct the alternative as a whole (constructability).
» Operational reliability or the ability of a technology to meet specified process
efficiencies or performance goals.
- Ability to undertake future remedial actions that may be required.
*• Ability to monitor the effectiveness of the remedy.
• Administrative Feasibility: The ability and time required to obtain any necessary approvals and
permits from regulatory agencies
-------
• Availability of Servim and Materials: The availability of the technologies, materials, or services
required to implement an alternative, including:
~ Available capacity and location of needed treatment, storage, and disposal
services.
- Availability of necessary equipment, specialists, and provisions for necessary
additional resources.
~ Timing of the availability of prospective technologies under consideration.
» Availability of services and materials, plus the potential for obtaining bids that are
competitive (this may be particularly important for innovative technologies).
All of the alternatives are technically feasible. Conventional equipment and construction practices are
required for implementation, operation, and monitoring under each alternative.
Alternatives 2 is readily implementable as it does not require permits for any off-site facilities. Alternatives
3 and 4 can be implemented only if a permitted off-site disposal facility is available for soil and sediment.
From an administrative viewpoint, Alternative 5 can be implemented only if permitted off-site incineration
and disposal facilities are available. Alternative 6 is readily implementable and does not require any
special administrative considerations to proceed.
Services and materials required for each alternative are readily available. As mentioned before, permits
will be required for any off-site disposal Disposal facilities should be available. A vendor is be available
for service for biological treatment process described in Alternatives 3 ami 6. The biocell at Site 22 is
available and operating for Alternative 4.
Cost;
For each remedial alternative, a detailed cost analysis was developed based on conceptual engineering and
analyses. Unit prices were based on published construction cost data, quotes from vendors and contractors,
and/or engineering judgment. Costs are expressed in terms of 1998 dollars. In order to allow the costs of
remedial alternatives to be compared on the basis of a single figure, the net present worth (NPW) value of
all capital and annual costs was determined for each alternative. The USEPA CERCLA RI/FS Guidance
Document recommends that a 5 percent discount rate be used in present worth analyses. Of the treatment
alternatives, Alternative 3 has the lowest NPW at $566,700. Alternative 4 is the next lowest at $592,000.
Alternative 5 has the highest NPW at $1,011,000. Alternative 6 has a NPW at $771,500, but one-third of
these costs (approximately $257,000) will be absorbed by the bioremediation technology vendor, making
Alternative 6 the most cost effective alternative.
2.8 J Modifying Criteria
State Acceptance:
The Commonwealth of Virginia was involved in the selection of the remedy for Sites 6 and 7. Information
regarding remedy selection was conveyed through Restoration Advisory Board (RAB) meetings, the FS
Report and at the public meeting. No state comments were received disputing the final remedy. The
Commonwealth is satisfied that the appropriate process was followed in evaluating remedial action
alternatives for Sites 6 and 7 and concurs with the selected remedy.
-------
community Acceptance:
WPNSTA Yorktown solicited input from the public on the development of alternatives and on the
alternatives identified in the Proposed Plan, A public meeting on the Proposed Plan was held on May 26,
1998. Community members of the Restoration Advisory Board (RAB) in attendance during the public
meeting agreed with die selection of Alternative 6 as the preferred alternative. No additional information
on the Proposed Plan has been requested and the 45 day public comment period closed on July 11, 1998,
with no additional comments being received on die selection of a remedy.
2.9 Selected Remedy
The Selected Remedy for the cleanup of explosives-contaminated soil at Site 6 is Alternative 6. This
alternative is protective of human health and the environment; complies with all ARARs; has a high degree
of short-term and long-term effectiveness and permanence; and reduces the toxicity, mobility, and volume
of wastes to be disposed of through removal and treatment. The Selected Remedy is more protective of
human health and the environment than Alternatives 3 and 4 because the treatment method in Alternative 6
is more likely to be effective than the treatment methods in the other alternatives. The Selected Remedy
will not produce residual ash, a drawback to Alternative S which utilizes incineration technology.
Alternative 6 may require the use of a commonly applied contingent technology such as low temperature
thermal desorption to reduce volatile contaminants to health based levels. The Selected Remedy is the third
least costly treatment alternative evaluated during the remedial process, if one does not consider that one*
third of these costs (approximately $257,000) will be absorbed by the bioremediation technology vendor.
If one does take the vendor's contribution into account, Alternative 6 is the least costly remedy. Table 2-
13 presents the detailed costs for the Selected Remedy.
2.10 Description of Selected Remedy and Performance Standards
The Selected Remedy requires the physical removal of residue in the trenches under Building 109. The
residue shall be transported to an on-site, permitted burning area for proper disposal. The trenches shall be
pressure washed after residue removal, and the waste water resulting from the steam cleaning shall be
collected and properly disposed. The remedy shall reduce contaminants to remediation levels presented in
Table 2-10. If a reasonable cycle of bioremediation is not able to reduce concentrations of chlorinated
VOCs in the soil to the remediation levels specified in Table 2-10, then low temperature thermal
desorption will be used to treat the soil and reduce concentrations of chlorinated VOCs to the remediation
levels in Table 2-10.
The Selected Remedy also requires the excavation of the Site 6-Flume Area soil/sediment contaminated
with nitramines/nitroaromatics, chlorinated volatiles, and inorganics to a depth of approximately 4 feet bgs.
Of the COCs identified for Site 6, the following RLs shall be used to identify soil and sediment to be
excavated:
• TCE
• Total cPAHs
• Total Amino-DNTs
16 mg/Kg
10 mg/Kg
10 mg/Kg
5.7 mg/Kg
5.0 mg/Kg
1.6 mg/Kg
14 mg/Kg
52 mg/Kg
410 mg/Kg
• KMX
• RDX
• 1,3,5-TNB
• 2,4,6-TNT
• Nickel
• Zinc
-------
Any soil or sediment in the Flume Area containing concentrations of these chemicals greater than the RLs
shown in the bullets above shall be excavated. The excavated soil and sediment shall be transported to a
staging and treatment area where it shall be treated by ex situ biological treatment.
-------
TABLE 2-13
SITE 6 COST ESTIMATE: RAA 6 - EX SITU BIOLOGICAL TREATMENT, SOIL COVER, LIMITED EXCAVATION, AND SLUDGE REMOVAL
NAVAL WEAPONS STATION YORKTOWN, YORKTOWN, VIRGINIA

MwaT

—
Cost Component
Unit
Quantity
Unit Coil
Cost
Total Com
Source

DIRECT CAPITAL COSTS

General

Pie-coftttmciioo Submittals
LS
1
$20,000
$20,000

Engr. Eu.
Wotk. E&S, HAS, & QC Run; Permits; Stop Drawings
Treatability Study
LS
1
126.670
$26,670

Engl. Est.; vendue quote
In situ biological ttewnent bench-scale nudy
MobiliaiHW/Demobiluiliao
LS
1
1110.000
$110,000

Engr. Ett.
Includes mobc/demobe for ill subconctractort
Dtfonfiiintion Pad
LS
1
$10,000
$10,000

Engr. Eu.
Includes decon/laydown area
Stockpile Are*
LS
I
$10,000
$10,000

Eagi. Ett.
Stockpile area for treated toil
CaMnci Adaraittfalion
LS
1
$40,000
$40,000

Engl. Est.
Invoicing, project management, field supervision. HAS. etc.
Poet-Contfniaion SubraittaU
LS
1
$10,000
$10,000

Engr. Eu.
Recotd drawings, etc.
C«Ntal • Subtotal

$226,670

Sit* Woii

Oaarittg and Grabbing
Acre
0.3
$1,300
$390

Engr. Eit;; Menu Site Wotk, 1991.021-104-0150
For wooded areas at SAOC13
Taaporary Safety Fencing
Lf
1,100
53.32
$3,652

Eagr. Eu.; Meant Site Wotk, 1991,028-320-SQ00
Attumet safety fencing around SAOCi *1 and *3
TMfMmy Sik Fammi
LF
700
$0.12
$574

Eagr. Eit.; Means Site Work, 1991,022-704-1000
Assumes tilt fencing at SAOCt *1 and *3
Slit lUttoretkm:

Astume 5 feet afbnckflU from on-site borrow pit (no material cotts) at
Backfill
CY
370.00
$3.60
$2,072

Engr. Ett.; Meant Site Wink, 1991, AI2.1-724-1400
SAOC VI
Attunes 4" of top toil at SAOC tt 1; cost includes mail, hauling (font
TopM.1
CY
25
$17.04
$426

Engr. Ett.; Meant Site Wotk, I99S, 022-216-7000
stockpile A compacting
Rat Grading/Siding (Re vegetation)
SY
220
$2.1*
$412

Engr. Em.; Mum Site Wort, 1991,022-216-1000
Revegctation over SAOOfl
Site Work • Subtotal

$7,596

Sludg» Mnoval

Assumes sludge residue is excavated by hand; assumes 1/2 inch of
Excavation Fran Building 109
CY
IS
$73.50
$1,323

Engr. Est.; Meant Site Wort, 1991,022-250-0220
sludge under entire ana of Building 109.

Attune* aw* and equip, natal con/fa day - $40.43/dty; 200 git/Iit
Stcaa Clean Building 109
LS
1
$400
$400

Engl. Eit.; Meant Site Wotk, 1991,0I6-42O-631O
unit; 10 dayt
Grout Cidvarta Leading to Concrete Flume
CF
5,5
$3.50
$30

Engr. En,Means Site Work, 1991,041-024-2600
includes material and labor.
Wtata WawColMott and Disposal
LS
1
$5,000
$5,000

Engr. Eit.

Hading Sludge 10 Treacneoi Area
Sludge R—oval - Subtotal
CY
II
$6 55
$111
tt.871
Engr. Ett.; Meant Site Wotk, 1991.022-2664)100
Assumes 2 mile round trip haul to on-sile pennined burning ilea.
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TABLE 2-13 (continued)
SITE 6 COST ESTIMATE: RAA 6 - EX SITU BIOLOGICAL TREATMENT, SOIL COVER, LIMITED EXCAVATION, AND SLUDGE REMOVAL
NAVAL WEAPONS STATION YORKTOWN, YORKTOWN, VIRGINIA
Off-Sitt Disposal for SAOC #2

Confirautoiy Sampling • Labor
HX
40
$40
$1,600

Eagr. En.
1 person for 1 week
Saaapliag - Travel/Per Djqp
LS
1
11,500
$1,900

Enfr.Etl.
Airfare, per dietn. hotel, rental car for 3 days for 1 person
Confimatko SedimesU Sampling • Analysis

Inorganics
w«

Assumes 20 samples for delineation and 2 samples for confirmation
22
$149
$3,190

Baker Average BOAs
durinf excavation (assuming sediment will be excavated).
Miscellaneous Expenses

hrimt*. H« imwI, ha« ~f-[— —» "—ftjug ft iftrfTi trrpm'lnMii.
Ev«M
I
1200
$200

Eo|r. Est,
ice k Dl water
lUporting
LS
1
SJ.OOO
$3,000

Engr. Est.
Letter report
EuavMiaa
CY
4
$1.61
$7

Engr. Est.; Means Site Wotk, 1991,022-238-0260
Assumes 1 foot deep excavation in a 100 sqarc foot area.

Includes transportation, disposal costs; assumes 1 to 1 conversion
Off Site Dapoul
To
3
S1C0
$900

Eagr. Est.
factor far cy lo ton; mwts 1.2 bulking factor of in place cubic yards
SJ»IU*or«tk«

Assumes 1" of backfill fen on-site borrow pit (no material costs) at
p^ffm
CY
2.3
$3.60
$U

Eagr. Est.; Meat Site Work. 1991, AI2.I-724-I400
SAOC»3; axccounta for 1.2 shrinkage factor when placed

Assumes 4" of top soil; cost includes mat'l, hauling from stockpile ft
Topnoil
CY
I.J
$17.04
$26

Eagr. Est.; Mmm Site Work. 1998.022-216-7000
rnmpnrting at nickel contaminated area at SAOC *2

Itovegatatioa ovsr all excavation arena at nickel contaminated area at
Fit Gradiag/Swding (Revegemion)
SY
13
$2.19
$33

En|r. Est.; Means Site Work. 1991.022-216-1000
SAOC #2
Off-Sit* Disposal for SAOC »2 - Subtotal

Soil Caw * SAOC «

Backfill
CY
ISO
$7.20
$1,296

E^r- Est.; Means Site Work. 1991.022-216-4000
Includes borrow, loading and spreading

Assumes 4" of top soil at SAOC '3; cost includes mat'l, hauling from
TaptaU
CY
90
$17.04
$1,334

E«|r. Est.; Mens Site Wort. 1991,022-216-7000
stockpile A compacting
Fix OndiatfSMdiat (Revcgetatioc)
SY
100
$2.19
$1,732

Eagr. Est.; Means Site Work. 1991.022-216-1000
Revcgetation over SAOC #3
Soil Cov» at SAOC >3 • Subtotal

$4,312

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TABLE 2-13 (continued)
SITE 6 COST ESTIMATE: RAA 6 - EX SITU BIOLOGICAL TREATMENT, SOIL COVER, LIMITED EXCAVATION, AND SLUDGE REMOVAL
NAVAL WEAPONS STATION YORKTOWN, YORKTOWN, VIRGINIA
Ex Situ Biological Treatment

1
Excavation
CY
370
$1.68
$622

Engr. Est.; Means Site Woci, 1948,022-2)8-0260
SAOC »1 (370 cy in place)
Sampling ¦ Labor
Hn.
20
S40.00
$800

Engr. Est.
SAOC # 1; I day/event; 2 gcoVeng. samplers % $40/hr ea.; 10 today
Confirmation Sediment Sampling • Analysis

VOCt
Sample
40
$126
$5,040

Baker Average BOAs
Assumes 40 samples during treatment.
Nitraraines
Sample
40
$150
$6,000

Baker Average BOAs
Assumes 40 samples during treatment.
Misrrll—nui Fwptntts

Includes Hw natal, HAS equipment, sampling A decon expendibles.
Event
1
$200
$200

Engineering Estimate
ice A Dl water
Reporting
LS
1
$5,000
$5,000

Engr. Est.
Letter report

Assumes 12 CY dump nailer, 1/4 mile round trip to existing bioceil;
Transport lo Staging and Treatment Ana
CY
600
$2.51
$1,541

Engr. Est.; Means Site Worit, 1998,022-266-0310
assumes 1.2 bulking factor of 370 cy in place sediment

factor during excavation; includes additives (1.2 factor increase in
Biological Treatment
Ton
600
$150
$90,000

Vendor Quote
volume), soil mixing equipment operation, labor
Ex Situ Biological Treatment • Subtotal

$108,511

OffSke Diaposal at SAOC #1

Includes hauling, disposal fees and taxes; assumes 1 lo 1 conversion
Disposal of Listed Waste
TON
JO'
$536.00
$26,800

Vendor Quote
factor from cubic yards to tons, and 1.2 bulking factor.
Off-Site Disposal at SAOC »1 • Subtotal

$26,800

DIRECT CAPITAL COSTS - TOTAL

$381,107

INDIRECT CAPITAL COSTS

Eaguweiixg a*d Design
LS
1
$22,866
$22,166

Engr. Est.
Assume 6% of Total Direct Capital Costs
Contingency Allowance
LS
1
$57,166
$57,166

Engr. Est.
Assume 15% of Total Direct Capital Costs
INDIRECT CAPITAL COSTS - TOTAL

$80,032

CAPITAL COSTS (DIRECT AND INDIRECT)
$441,139

-------
TABLE 2-13 (continued)
SITE 6 COST ESTIMATE: RAA 6 - EX SITU BIOLOGICAL TREATMENT, SOIL COVER, LIMITED EXCAVATION, AND SLUDGE REMOVAL
NAVAL WEAPONS STATION VORKTOWN, YORKTOWN, VIRGINIA
ANNUAL OPERATION AND MAINTENANCE CC
tSTS

Moattoriag

Sampling - Labor
Hn.

AimuiI sampling at SAOC *2; 2 dayj/event; 2 gcoJeng. uaplers @
120
140.00
$4,100

Eogr. Em.
$40Av ea.; 1 eveni/yr, 10 his/day
S—plim • Tnvet/Pcr Diem
Evmi
1
$2,100
$2,100

Fn|r. Eii.
Airfare, per diem, hotel, rental car for 3 dayi for 2 people
Stdiaaat Sipliig. Aaalytit

VOCl
Sample
6
SI26
$756

Baker Average BOA*
6 samples al SSAOCK2; 1 eveni/yr
SVOCi
Saaple
6
$225
$1,350

Biker Avenge BOAl
6 samples at SSAOC02; 1 eveal/yr
Nknaiota
Sample
6
$150
$900

Biker Average BOA*
6 simples at SSAOC02; 1 cvcol/yr
Otwdwmr mi Surface Water Sampling - Aaalyau

10 grouadwater sampUs/event; 10 surface water umplet/evmt; 1
VOCi
Sample
10
$110
$1,100

Baker Avenge BOAi
evtat/yr

10 grouadwatar sampMaveol; 10 surface water uenpiei/evmi; 1
SVOCi
SMipl*
10
$200
$2,000

Baker Average BOAi
eveM/yr

3 groundwater samplea/event; 3 surface wata umpJei/evesi, 1
Njuaauac*
Sample
10
$130
$1,500

Baker Average BOAi
event/yr

im-iaAff Hiii rMttl, HAS uoptkf A
MttttUiMOui Fipntft
Evtnt
1
$200
$200

FfttfaffTwg Eitunilfe
ice A Dl water
ftaponiag
LS
1
$5,000
$5,000

Eagr. Em.
Letter report
Mcaaonai • Subtotal

$19,706

SAOC M MiiKfft

Cap Repair
SF
720
$0.70
$504

Engr. En.; Meant Site Wort. 1998,029-316-1200
Assumes 10% of toil cover area will require maintenance every year.
SAOC #3 MtiMtoMc* - Subtotal

$504
•

J2MI0

TOTAL NIT PRESENT WORTH: RAA «

$771,500
By: ELB Ok: CMC
Dale Completed: April 9,1991
-------
Habitat at the Site 6 - Flume area shall be restored.
A soil cover (minimum 8 inches) shall be placed over the cadmium and zinc contaminated surface soil at
the Site 6 - Excavated Area, The soil cover shall require long-term maintenance.
Long-term sediment, surface water, and groundwater monitoring shall be conducted at the Site 6 -
Impoundment Area, (OU XV) in accordance with a long term monitoring plan which shall be approved by
the LTSEPA, the VDEQ and the Navy. If area groundwater quality or Site 6 - Impoundment Area surface
water and sediment quality degrades, posing a risk to human health and the environment, further remedial
action may have to be evaluated.
WPNSTA Yorktown shall prohibit (i) residential use of the area surrounding the Site 6 - Flume Area, (ii)
residential use of the area surrounding the Site 7 - Drainage Area and (Hi) activities that interfere with or
compromise the integrity of the soil cover at the Site 6 - Excavated Area. These are the "land use control
objectives" for Sites 6 and 7. The precise boundaries of the areas in which residential use is prohibited
shall be fixed during the development of the Land Use Control Implementation Plan described in the next
paragraph.
Within 90 days of the execution of this ROD, WPNSTA Yorktown shall develop a Land Use Control
Implementation Plan (LUCIP) with the concurrence of EPA Region III and in consultation with the
Commonwealth of Virginia. The LUCIP shall include:
(1) a description and the location of Sites 6 and 7, including a map, a description of
their approximate size and a description of the COCs; '
(2) the land use control objectives (LUCs) selected above;
(3) the particular controls and mechanisms to achieve these goals;
(4) a reference to this ROD; and
(5) any other pertinent information.
Within 180 days following the execution of this ROD, the Navy, with the concurrence of EPA Region III
and in consultation with the Commonwealth of Virginia, shall develop a Land Use Control Assurance Plan
(LUCAP) for WPNSTA Yorktown, The LUCAP shall contain Station-wide periodic inspection, condition
certification and agency notification procedures designed to ensure the maintenance by Station personnel
of any site specific LUCs deemed necessary for future protection of human health and the environment,
including LUCs selected in this ROD. A fundamental premise underlying execution of the LUCAP is that
through the Navy's substantial good-faith compliance with procedures called for therein, reasonable
assurances will be provided to USEPA and the Commonwealth of Virginia as to the permanency of those
remedies which include the use of specific LUCs.
-------
Although the terms and conditions of the LUCAP will not be specifically incorporated or made
enforceable as to this or any other ROD, it is understood and agreed by the Navy, USEPA and the
Commonwealth ofVirginia that the contemplated permanence of the remedy reflected herein shall be
dependent upon the Station's good-faith compliance with specific LUC maintenance commitments
reflected herein. Should such compliance not occur or should the LUCAP be terminated it is understood
that the protectiveness of the remedy concurred in may be reconsidered and that additional measures may
need to be taken to adequately ensure necessary future protection of human health and the environment.
2.11 Statutory Determination
The Selected Remedy for Site 6 satisfies the requirements under Section 121 of CERCLA to:
* Protect human health and the environment
• Comply with ARARs.
* Use permanent solutions and treatment technologies/resource recovery technologies to the
maximum extent practicable.
• Satisfy the preference for treatment as a principal element.
2.11.1 Overall Protection of Human Health and the Environment
The Selected Remedy will provide a significant reduction in risks to human health and the environment
through removal and biological treatment of soil/sediment in the Flume Area; a cover at the Site 6-
Excavated Area; monitoring of groundwater, surface water, and sediment in the Site 6-Impoundment Area;
and the removal and disposal of residue from AOC C and SWMU 179 (Building 109). As such, this
alternative will protect human health and the environment. The potential source of contamination to other
environmental media will be removed or covered.
2.11.2 Compliance with ARARs
The selected remedy for Site 6 complies with all Federal and state location and action specific ARARs as
outlined below. Chemical specific ARARs or to-be-considered criterion (TBCs) are not available for soil
or sediment; therefore, risk-based RL's were developed that are protective of both human health and the
environment
-------
I oeation-Spccific ARARs
• Migratory Bird Treaty Act
(16 U.S.C. 703-712)
Action to prohibit any disturbance to nesting sites of listed migratory birds will be
implemented. The remedial action will be planned such that the osprey nesting sites near Site 6
will not be disturbed.
• National Historic Preservation Act
(32 CFR Parts 229 and 229.4; 43 CFR Part 171; and 36 CFR Part 800)
Archeological resources encountered during excavation must be reviewed by Federal and
Commonwealth archeologists. The Act also applies to potentially historic buildinp. Building
109 is a World War II era building. The WPNSTA Yorktown Environmental Directorate and
Draft Historic Preservation Plan for WPNSTA Yorktown will be contacted and reviewed prior
to development of the Remedial Action Work Plan.
• Executive Order 11990 Protection of Wetlands
(40 CFR 6, Appendix A; excluding Sections 6(a)(2), 6(a)(4), 6(a)(6); 40 CFR 6.302)
Action to minimize the destruction, loss, or degradation of wetlands that could be impacted by
a remedial action. Monitoring of die Site 6-Impoundment Area is preferred over active
remediation to maintain existing wetlands habitat. Erosion from excavation activities coukl
affect the Site 6-Impoundment Area. An erosion control plan will be established as part of the
Remedial Action Work. Plan.
• Clean Water Act, Section 404,33 U.S.C. 1344
(40 CFR 230.10; 40 CFR 231 (231.1,231.2,231.7,231.8))
Action to prohibit discharge of dredged or fill material into a wetland without a permit if the
discharge of dredge or fill is planned as part of the remedial alternative. No material taken
from either Site 6 or removed from die bioremediation staging and treatment area after
treatment will be discharged or placed into wetlands.
• Virginia Wedands Regulation
(VR 450-01-0051/4 VAC 20-390-10 to -50)
Regulates activities that impact wetlands. The remedial action will be undertaken in such a
way as to limit potential impacts on wetlands via erosion from Site 6 during excavation and
reuse of treated soil/sediment
Action-Soecific ARARs
• Resource Conservation and Recovery Act (RCRA)
Subtitle C, 42 U.S.C. 6921-6939e
Applicable to any action at WPNSTA Yorktown involving treatment, storage, or disposal of
hazardous waste.
Identification and Listing of Hazardous Waste
(40 CFR Part 261)
Any wastes hazardous by characteristic must be identified as part of the remedial
action. Soil/sediment at the Site 6-Flume Area is contaminated by chlorinated
volatiles, considered a hazardous waste by listing (RCRA F002)
-------
Releases from Solid Waste Management Units
(40 CFR Part 264, Subpart F)
All units on-site will comply with substantive requirements concerning potential
releases. This ARAR applies to the biological treatment area and Building 109.
Use and Management of Containers
(40 CFR Part 264, Subpart I)
Regulates the use and management of containers being stored at all hazardous
waste facilities. Remediation may generate containerized waste, such as 1DW.
The Selected Remedy reduces the use of containers because a portion of the Site 6
soil/sediment will be treated at the staging and treatment area near Site 6. Also,
the surface soil at the Site 6-Excavated Area will not be excavated or moved.
»
Land Treatment
(40 CFR Part 264, Subpart M)
Regulates design, treatment demonstration, operating equipment, monitoring,
closure and post-clasure care of the treatment cell and treatment area. The
selected remedy shall meet these requirements.
• Virginia Hazardous Waste Management Regulations
(VR 672-10-1/9 VAC 20-60-10 et seq.)
Regulates the treatment, storage, and disposal of hazardous waste.
Identification and Listing of Hazardous Waste
(VR 672-10-1, Part III; 9 VAC 20-60 Part III)
Applies to determining waste types by characteristic. Soil and sediment at the Site
6-Flume Area is contaminated by waste that is hazardous by listing (RCRA
F002).
Releases from Solid Waste Management Units
(VR 672-10-1, Part X, Section 10.5; VAC 20-60-790)
Applies to owners/operators of facilities that treat hazardous waste. Regulates
potential releases from all onsitc solid waste management units. This ARAR
applies to the biological treatment area and to Building 109.
Land Treatment
(VR 672-10-1, Part X, Section 10.12; 9 VAC 20-60-860)
Regulates design, treatment demonstration, operating requirements, monitoring,
and closure and post-closure care of the treatment cell and treatment area.
Use and Management of Containers
(VR 672 -10-1, Part X, Section 10.8; 9 VAC 60-20-820)
Applies to Site 6 where the IDW associated with confirmation sampling may be
containerized before off-site disposal.
• Virginia Erosion and Sediment Control Regulation*
(VR 625-02-00; 4 VAC 50-30-10 to -110)
Applicable for remedial actions involving land disturbing activities. Activities including the
excavation at Site 6 will have an erosion control plan submitted to Atlantic Division, Naval
Facilities Engineering Command (LANTDIV) for approval.
-------
2.11.3 Cost Effectiveness
Of the four "treatment" alternatives, the Selected Remedy (Alternative 6) is the most cost effective. It
provides maximum long-term protection of human health and the environment and short-term protection of
human health and the environment. It is the least costly of the treatment alternatives (considering that a
portion of the cost of treatment will be shared by the treatment technology vendor) and will addresses all
contaminant types.
2.11.4 Use of Permanent Solutions and Alternative Treatment Technologies or Resource Recovery
Technologies to the Maximum Extent Practicable
The selected remedy is a permanent solution and uses treatment technologies to the maximum extent
practicable. Contaminated Site 6 - Flume Area soil and sediment will be treated at the staging and
treatment area using biological treatment to destroy nitramines/nitroaromatics and chlorinated volatiles. A
contingent technology such as low temperature thermal desorption may be employed to address chlorinated
volatiles. The clean soil will then be taken from the staging and treatment area and used as fill at the
Station. The soil cover at the Site 6 - Excavated Area is not a treatment technology but will reduce
mobility of the inorganic contaminants by preventing contact with runoff and infiltration. Permanence of
the soil cover will depend on long-term maintenance.
2.12 Documentation of Significant Change*
The Proposed Plan presents the selected remedy as the preferred alternative. No significant changes to the
remedy have been made.
3.0 RESPONSIVENESS SUMMARY
The final component of this Record of Decision is the Responsiveness Summary. The purpose of this
section is to provide a summary of the public's comments, concerns, and questions about Sites 6 and 7,
During the public comment period, written comments, concerns and questions were solicited. An
announcement of the public comment period and the public meeting was published in the Daily Press on
May 24, 1998. A public meeting was held on May 26, 1998 at the York County Recreational Services
Building to formally present the Proposed Plan and to answer questions and receive comments. Hie
transcript of this meeting is presented in Appendix C of this Record of Decision. All comments and
concerns concerning the remedy have been considered by the. DoN and USEPA in the selection of the
remedial alternatives for Sites 6 and 7.
The responsiveness summary is divided into the following sections:
• Overview
• Background on community involvement
• Summary of comments received during the public comment period
-------
3.1 Overview
At the time of the public meeting, the DoN had endorsed No Further Action to protect human health and
the environment at Site 7, WPNSTA, Yorktown.
In addition, the DoN endorsed a preferred alternative for Site 6, WPNSTA, Yorktown, for the cleanup of
explosives-contaminated soil/sediment at the Site 6 - Flume Area, explosives and volatile contaminated
soil/sediment at the Site 6 - Impoundment Area and inorganic contaminated soil at the Site 6 - Excavated
Area. The alternative required removal and disposal of residue from the trenches under Building 109 and
excavation and ex situ biological treatment of contaminated sediment and soil from the Site 6 - Flume
Area. Site 6 - Flume Area soil and sediment would be treated using a nutrient source to enhance
indigenous microbe growth to biologically degrade the contaminants. A soil cover would be installed over
and around the cadmium- and zinc-contaminated soil at the Site 6 - Excavated Area. This would prevent
the soils with cadmium and zinc concentrations above the RLs of 4.0 mg/kg and 48.4 mg/kg, respectively,
from coming into contact with the ecological receptors. Long-term sediment, surface water, and
groundwater monitoring would be conducted at the Site 6-Impoundment Area and surrounding area to
assess the potential impact to human health and the environment and to preserve wetland habitat. USEPA
Region III and the Commonwealth of Virginia concurred with the preferred alternative.
There were no comments received from the community during the public comment period in opposition to
the proposed remedy. Community members of the Restoration Advisory Board (RAfi) in attendance
during the public meeting agreed with the selection of Alternative 6 as the preferred alternative.
3.2 Background on Community Involvement
Nearby communities have a good working relationship with WPNSTA Yorktown because the Station
maintains a good neighbor policy through the Public Affairs Office. WPNSTA Yorktown participates in
community events and celebrations to foster close ties with the community. As part of the ongoing
Community Relations Program (CRP), community interviews were conducted in 1991 to inform the
community of the IR Program and solicit feedback on the listing of WPNSTA Yorktown as an NPL site.
The community expressed concern about three issues: water resources, cleanup funding, and information
availability/validity. This public openness has been maintained by the Public Affairs Office and the
Environmental Directorate at WPNSTA Yorktown through the CRP and resulted in the formation of the
RAB. The WPNSTA RAB is comprised of agency representatives, technical and business people, and
members of the community at large. The RAB meets regularly and progress at sites such as Sites 6 and 7
is discussed from the work plan stage to selection of the remedial alternative (if necessary). Preliminary
Site 6 and 7 results were discussed at several past and at the most recent RAB meetings. No significant
comments were received for either site at these meetings.
3*3 Summary of Comments Received During the Public Comment Period
The Public Comment Period closed on July 11, 1998. A copy of the revised final PRAP is presented in
Appendix D.
-------
APPENDIX A
HUMAN mAVTH COPC SUMMARIES
-------
TABLE A-l
SURFACE SOIL STATISTICAL SUMMARY OF HUMAN HEALTH CHEMICALS OF POTENTIAL CONCERN
FROM SURFACE SOIL SAMPLE ANALYSIS
SITE 6 - IMPOUNDMENT ARIA (ROUND ONE)
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
CHEMICAL
FREQUENCY
OF
DETECTION
RANGE OF
DETECTED
CONCENTRATIONS
(mg/kg)
ARITHMETIC*
MEAN
(mg/kg)
RANGE OF
STATION
BACKGROUND
(mg/kg
Semivolaiiles:
Benzo(a)anthracene
Benzo(a)pyrene
Benzc(b)fluoranthene
Benzo(k)fluoranthene
Chrysene
Dibenzo(a,h)anthracene
Indeno (1,2,3-cd) pyrene
Inorganics:
Aluminum
Arsenic
Beryllium
Iron
2/7
2/7
2/7
2/7
2/7
1/7
2/7
7/7
7/7
7/7
in
0.036J* f*
Th-*?
frit ies.J//'I /-'/sf ~ 'J
at'£ i's-/

&d>
5,790.00
4.76
0.49
14,914.29

1,960 - 24,100
0.466 - 63.9
0.23J - 0.93J
1,440-46,400

r~2?
) f-
Notes:
J = Anatyte was positively identified, value is estimated.
K = Analyte was positively identified, value is biased high.
L = Analyte was positively identified, value is biased low.
* The arithmetic mean is calculated using positive detections and one half of the detection limit for non-detections.
-------
TABLE A-2
SURFACE SOIL STATISTICAL SUMMARY OF HUMAN HEALTH CHEMICALS OF POTENTIAL CONCERN
FROM SURFACE SOIL SAMPLE ANALYSIS
SITE 6 /t>RAlNACF\\RE A (ROUND TWO AND SUPPLEMENTAL INVESTIGATION)
"NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA

RANGE OF

FREQUENCY
DETECTED
ARITHMETIC*
STATION •

OF
CONCENTRATIONS
MEAN
BACKGROUND
CHEMICAL
DETECTION
(mg/kg)
(mg/kg)
(mg/kg)
Inorganics:

Aluminum
5/5
6,230-11,200
8,338.00
1,960 - 24,100
Antimony
1/2
13.8L
8.93
9.2L- 11L
Arsenic
5/5
1.6L-7.6L
4.50
0.46L - 63.9
Beryllium
5/5
0.48-0.68
0.59
0.23J - 0.93J
Iron
5/5
5,570-23,900
15,330.00
1,440 - 46,400
Manganese
5/5
48.1-206
121.30
7.6L- 491
Notes:
J = Analyte was positively identified, value is estimated.
L = Analyte was positively identified, value is biased low.
* The arithmetic mean is calculated using positive detections and one half of the detection limit for non-detections.
-------
TABLE A-3
SURFACE SOIL STATISTICAL SUMMARY OF HUMAN HEALTH CHEMICALS OF POTENTIAL CONCERN
FROM SURFACE SOIL SAMPLE ANALYSIS
SITE 6 - EXCAVATED AREA
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA

RANGE OF

FREQUENCY
DETECTED
ARITHMETIC*
STATION

OF
CONCENTRATIONS
MEAN
BACKGROUND
CHEMICAL
DETECTION
(mg/kg)
(mg/kg)
(mg/kg)
Inorganics:

Aluminum
6/6
13.I00J-27.000J
19,550.00
1.960 - 24,100
Antimony.
1/6
11.9L
6.49
9.2L- 11L
Arsenic
6/6
4.1-8
5.92
0.46L- 63.9
Beryllium
6/6
0.47-0.82
0.64
0.23J - 0.93J
Cadmium
2/6
3.4L-18.4L
4.09
1.2J-1.5
Chromium
6/6
20.1-52.2
36.77
2.6 - 33.5
Iron
6/6
14,400J-35,300J
24,433.33
1,440-46,400
Zinc
6/6
93.1J-2,340J
934.18
3.2KJ - 48.4
Notes:
J = Analyte was positively identified, value is estimated.
K - Analyte was positively identified, value is biased high.
L = Analyte was positively identified, value is biased low.
ND = Not Detected
* The arithmetic mean is calculated using positive detections and one half of the detection limit for non-detections.
-------
TABLE A-4
SUBSURFACE SOIL STATISTICAL SUMMARY OF HUMAN HEALTH CHEMICALS OF POTENTIAL CONC1
FROM SUBSURFACE SOIL SAMPLE ANALYSIS
SITE 6 AREA
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
RANGE OF RANGE OF
FREQUENCY DETECTED ARITHMETIC* STATION
OF CONCENTRATIONS MEAN BACKGROUND
CHEMICAL
DETECTION
(mg/kg)
(mg/kg)
(mg/kg)
Volatiles:

1,1-Dichloroethene
1/20
0.12
0.01
-
cis-1,2-Dichloroethene
3/17
0.04IJ-3.1J
0.25
..
trans-1,2-Dichloroethene
2/20
0.01J-0.26
0.02

Tetrachioroethene
1/20
0.0161
0.01
•
1,1,2,2-Tetrachloroethane
1/20
0.003J
0.01
—
1,1,2-Trichloroethane
1/20
0.008J
0.01
..
Trichloroethene
4/20
0.012-3.4J
0.21
..
Vinyl Chloride
1/20
4.7J
0.24
~
Ntiramines:

2-Amino-4,6-Dinitrotoluene
1/17
2.5
0.62
—
4-Am»no-2,6-Dinitrotoluene
1/17
2.5
0.62
—
RDX
3/20
46-160
13.85
—
1,3,5-T rinitrobenzene
1/20
21
1.42
—
2,4,6-Trinitrotoluene
3/20
410-640
79.70
—
Inorganics:

8.5L- 31.3L
Antimony
6/13
8.41-13.1L
7.11
Arsenic
20/20
0.82-15.8
5.37
0.23J - 43.7
Beryllium
20/20
0.31-0.9
0.53
0.31 - 9.8
-------
TABLE A-4 (Continued)
SUBSURFACE SOIL STATISTICAL SUMMARY OF HUMAN HEALTH CHEMICALS OF POTENTIAL CONCERN
FROM SUBSURFACE SOIL SAMPLE ANALYSIS
SITE 6 AREA
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA

RANGE OF

FREQUENCY
DETECTED
ARITHMETIC*
STATION

OF
CONCENTRATIONS
MEAN
BACKGROUND
CHEMICAL
DETECTION
(mg/kg)
(mg/kg)
(mg/kg)
Chromium
19/20
6-46.6
20.8
5.2L - 33,5
Iron
20/20
3,270-35,200
14,618.50
3,810-51,100
Manganese
20/20
21.2-314
117.59
3.51-2,840
Notes:
L = Estimated value, biased low
I = Analyte was positively identified, value is estimated.
* The arithmetic mean is calculated using positive detections and one half of the detection limit for non-detections.
-------
TABLE A-5
STATISTICAL SUMMARY OF HUMAN HEALTH CHEMICALS OF POTENTIAL CONCERN
FROM GROUNDWATER SAMPLE ANALYSIS
SITE 6 AREA
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
CHEMICAL
FREQUENCY
OF
DETECTION
RANGE OF
DETECTED
CONCENTRATIONS
(Mg/L)
ARITHMETIC*
MEAN
0*gfL)
RANGE OF STATION
BACKGROUND
(A
-------
TABLE A-6
SURFACE WATER STATISTICAL SUMMARY OF HUMAN HEALTH CHEMICALS OF POTENTIAL CONCERN
FROM SURFACE WATER SAMPLE ANALYSIS
SITE 6 - IMPOUNDMENT AREA
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
RANGE OF RANGE OF
FREQUENCY DETECTED ARITHMETIC* STATION
OF CONCENTRATIONS MEAN BACKGROUND
CHEMICAL DETECTION Qj g/L) Qig/L) fcg/L)
Volatiles:

1,2-Dichloroethene
1/4
Si

1, 1,2,2-Tetrachloroethane
1/4
11
4.00

Semivolatiles:

Benzo(a)anthracene
1/4
0.9J
4.10
—
Benzo(a)pyrene
1/4
0.61
4.03
—
Bcnzo(b)fluorantheiie
1/4
0.61
4.03
—
Benzo(k)fluoranthene
1/4
0.6J
4.03
-
Chrysene
1/4
0.9J
4.10
—
Phenanthrene
1/4
0.8J
4.08
--
Ntiramnes:

HMX
3/4
2.8-12
4.68
-
RDX
3/4
5.8-33
13.03
—
2,4,6-Trinitrotoluene
1/4
36
9.49
—
Inorganics:

171J- 5,600
Aluminum
4/4
I78J-17,900J
6,624.50
Arsenic
3/3
3.2-10.4
5.73
1.2L-3.5L
Beryllium
2/4
1.3-2.1
1.10
ND
Chromium
3/4
17.3-61.2
25.73
ND
Iron
4/4
838J-45,OO0J
19,359.50
289J - 6,650
-------
TABLE A-6 (Continued)
SURFACE WATER STATISTICAL SUMMARY OF HUMAN HEALTH CHEMICALS OF POTENTIAL CONCERN
FROM SURFACE WATER SAMPLE ANALYSIS
SITE 6 - IMPOUNDMENT AREA
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
CHEMICAL
FREQUENCY
OF
DETECTION
RANGE OF
DETECTED
CONCENTRATIONS
O^g/L)
RANGE OF
ARITHMETIC^ STATION
MEAN BACKGROUND
Ofg/L) (Mg/L)
Lead
Manganese
Mercury
Vanadium
4/4
4/4
1/4
4/4
3.8-78.8J
51.41-4501
0.21
74.8-125
223.10
0.09
97.53
42.60 I.2L- 5.4L
33.1 - 379
ND
5J - 14.4J
Notes;
J - Analyte was positively identified, value is estimated
It s Value is estimated; biased high.
L = Value is estimated; biased low
ND = Not Detected
* The arithmetic mean is calculated using positive detections and one half of the detection limit for non-detections.
-------
TABLE A-7
SURFACE WATER STATISTICAL SUMMARY OF HUMAN HEALTH CHEMICALS OF POTENTIAL CONCERN
FROM SURFACE WATER SAMPLE ANALYSIS
SITE 6-TRIBUTARY
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
CHEMICAL
FREQUENCY
OF
DETECTION
RANGE OF
DETECTED
CONCENTRATIONS
fog/L)
ARITHMETIC*
MEAN
(m g/L)
RANGE OF
STATION
BACKGROUND
(^g/L)
Votaliles:

1,1,1-T richloroethane
1/4
6J
5,25
—
inorganics:

Arsenic (carc)
1/4
1.8 J
1.05
1.2L- 3.5L
Iron
4/4
1,200-1,530
1,402.50
289J-1,150
Manganese
4/4
53.2-86.1
72.80
33.1 -379
Inorganics (Dissolved):

"
Arsenic (carc)
1/4
1.5J
0.91
1.2J- 13L
Manganese
4/4
18.6-44.4
29.38
2J - 290
Notes:
J = Anaiyte was positively identified, value is estimated
L = Value is estimated; biased low
•Xhe arithmetic mean is calculated using positive detections and one half of the detection limit for non-detections.
-------
TABLE A-8
STATISTICAL SUMMARY OF HUMAN HEALTH CHEMICALS OF POTENTIAL CONCERN
FROM SEDIMENT SAMPLE ANALYSIS
SITE 6 - IMPOUNDMENT
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA

RANGE OF

RANGEOF

DETECTED
ARITHMETIC*
STATION

FREQUENCY OF
CONCENTRATIONS
MEAN
BACKGROUND
CHEMICAL
DETECTION
(mg/kg)
(mg/kg)
(mg/kg)
Semlvolatilm

Benzo(a)an(hracene
2/8
0.2IJ-0.45J
0.3
..
Benzo(b)fluoranthene
2/8
0.29J-0.6|
0.33
--
Benzo(k)fluoranthene
2/8
0.083j42lP
• 0.2P

Benzo(a)pyrene
2/8
0.18J-0.4J
0.29
-
Chrysene
2/8
oms
0.31
..
lndeno( 1,2,3-cd)pyrene
1/8
nujK
0.27^>
-
Inorganics:

Aluminum
8/8
2,560-16,000
NC
482K- I7.700J
Arsenic (care)
8/8
1.5-23.8
NC
0.276 - 5.4L
Beryllium
5/9
0.33-0.86
NC
0.28J - 0.99J
Iron

8,130-27,000
NC
329 - 27.700J
Vanadium
(9/8 J
9.2-81.6
NC
I.9J-38.9
L ¦ Estimated value, biased low
K. = Estimated value, biased high
1 - Analyte was positively identified, value is estimated.
NC = Not Calculated
* The arithmetic mean is calculated using positive detections and one half of the detection limit for non-detections.
-------
TABLE A-9
SEDIMENT STATISTICAL SUMMARY OF HUMAN HEALTH CHEMICALS OF POTENTIAL CONCERN
FROM SEDIMENT SAMPLE ANALYSIS
SITE 6 - IMPOUNDMENT AREA
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
RANGE OF RANGE OF
FREQUENCY DETECTED ARITHMETIC* STATION
OF CONCENTRATIONS MEAN BACKGROUND
CHEMICAL
DETECTION
(mg/kg)
(mg/kg)
(mg/kg)
VolatUes:

1,1-Dichloroethane
2/55
0.052-4.5J
0.1

1,2-Dichloroethane
3/55
0.008J-88
1.62
—
1,1-Dichloroethene
1/55
0.44 „
0.17
..
1,2-Dichloroethene (Total)
3/53
0.009^0^
0.1?
-
Tetrachloroethene
2/55
0.091-180
3.29
--
1,1,1-Trichloroethane
2/55
0.03 IJ-190
3.48
-
Trichlorocthene
1/55
0.005J '
0.17
~
Vinyl Chloride
2/55
0.063(014
0.17

SemivolatUes:

Acenaphthene
6/55
0.068Jrt$P
0.6-

Anthracene
7/55
0.069J-6.8J
0.64
—
Benzo(a)anthracene
21/55
0.094J-9.1J
0.68

Benzo(b)fluoranthene
21/55
0.079J-2.4
0.72
—
Benzo(k)fluoranthene
16/55
0.088J-0.96J
0.6
—
Benio(g,h,i)perylene
16/55
0.086J-2.3J
0.55
—
Benzo(a)pyrene
26/55
0.094J-9.6J
0.69
—
Carbazole
3/55

—
Chiysene
21/55
0.I2I-I i
0.72
—
Dibenzo(a,h)anihracene
6/55
0.0624-0.3^
0.61

2,4-Dinitrotoluene
2/55
1.9-28J
1.13

-------
TABLE A-9 (Continued)
SEDIMENT STATISTICAL SUMMARY OF HUMAN HEALTH CHEMICALS OF POTENTIAL CONCERN
FROM SEDIMENT SAMPLE ANALYSIS
SITE 6 - IMPOUNDMENT AREA
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA

RANGE OF

FREQUENCY
DETECTED
ARITHMETIC*
STATION

•OF
CONCENTRATIONS
MEAN
BACKGROUND
CHEMICAL
DETECTION
(mg/kg)
(mg/kg)
(mg/kg)
2,6-Dinitrotoluene
1/55
0.55J
0.6
—
Fiuorenthene
26/55
0.067J-3.9
0.74
—
Fluorene
4/55
0.065J-5J
0.62
—
lndeno( 1,2,3-cd)pyrene
13/55
0.097J-l. 8
0.63
—
2-Methyinaphthaiene
4/55
0.17J-0.45)
0.«P
~
Naphthalene
1/55
0.067J
0.65
«
Phenanthrene
18/55
0.0841-15
0.8
..
Pyrene
30/55
0.063J-22
1.07
'
Niiramines:

4-Amino-2,6-Dinitrotoluene
8/46
0.098N-520N
11.52
..
1,3-Dinitrobenzene
1/55
0.210N
0.11

HMX
2/55
96-710
15.19
--
RDX
2/55
63-160
4.36
—
1,3,5-Trinitrobenzene
3/55
0.45N-19
0.67
—
2,4,6-Trinitrotoluene
10/55
0.13N-2.500N
45.86
—
Inorganics:
Aluminum
11/11
2,150J-38,900
9,500.91
1,510-40,500
Antimony
Arsenic (carc)
Beryllium
Cadmium
1/11
11/11
7/11
5/11
48.2
4-22.1
0.73-1.7
2.5-9.8
18.19
8.03
1.00
3.74
18.9L
1.4J-13.1
0.55J- 1.6J
ND
-------
TABLE A-9 (Continued)
SEDIMENT STATISTICAL SUMMARY OF HUMAN HEALTH CHEMICALS OF POTENTIAL CONCERN
FROM SEDIMENT SAMPLE ANALYSIS
SITE 6 - IMPOUNDMENT AREA
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
CHEMICAL
. FREQUENCY
OF
DETECTION
RANGE OF
DETECTED
CONCENTRATIONS
(mg/kg)
ARITHMETIC*
MEAN
(mg/kg)
RANGE OF
STATION
BACKGROUND
(mg/kg)
Chromium
11/11
9.8-94.8
34.40
3.8-66.1
Iron
11/11
9,120J-61,600
23,220.00
3,060 - 46,000
Manganese
11/11
60.9J-245
135.20
7.4-1,980
Nickel
9/11
12.5-100
40.60
9.3K - 55.2
Vanadium
11/11
39.6-382
145.96
4.8J - 67.6
Zinc
11/11
45.8-643
277.16
4J - 202J
Notes:
J = Analyte was positively identified, value is estimated.
K ** Estimated value; biased high.
ND = Not Detected
~ The arithmetic mean is calculated using positive detections and one half of the detection limit for non-detections.
-------
TABLE A-10
SEDIMENT STATISTICAL SUMMARY OF HUMAN HEALTH CHEMICALS OP POTENTIAL CONCERN
FROM SEDIMENT SAMPLE ANALYSIS
SITE 6-TRIBUTARY
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
RANGE OF RANGE OF
FREQUENCY DETECTED ARITHMETIC* STATION
OF CONCENTRATIONS MEAN BACKGROUND
CHEMICAL DETECTION (mg/kg) (mg/kg) (mg/kg)
Inorganics:
Aluminum
8/8
9,430-33,300
24,528.75
1,510-40,500
Arsenic (carc)
8/8
4.5-11.2
8.74
1.4J-I3.1
Beryllium
7/8
1.1-1.5
1.13
0.55J -1.61
Chromium
8/8
20.2-58.8
45.81
3.8-66.1
Iron
8/8
19,000-39,900
34,000.00
3,060 - 46,000
Manganese
8/8
67.1-286
213.01
7.4-1,980
Vanadium
8/8
37.2-81.9
59.96
4.8J-67.6
Notes:
J - Analyte was positively identified, value is estimated.
ND = Not Detected
~ The arithmetic mean is calculated using positive detections and one half of the detection limit for non-detections.
-------
TABLE A-ll
SURFACE SOIL STATISTICAL SUMMARY OF HUMAN HEALTH CHEMICALS OF POTENTIAL CONCERN
FROM SURFACE SOIL SAMPLE ANALYSIS
SITE 7-STUDY AREA
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA

RANGE OF

FREQUENCY
DETECTED
ARITHMETIC*
STATION

OF
CONCENTRATIONS
MEAN
BACKGROUND
CHEMICAL
DETECTION
(mg/kg)
(mg/kg)
(mg/kg)
Inorganics:

Aluminum
4/4
6,010-19,100
13,552.50
1,960 - 24,100
Antimony
1/4
I8.6L
8.09
9.2L- 11L
Arsenic
4/4
4.5-11
7.15
0.46L - 63.9
Beryllium
4/4
0.48-0.95
0.72
0.23J - 0.93J
Cadmium
1/4
6
1.96
I.2J-1.5
Chromium
4/4
13.7-40.2
29.88
2.6-18.3
Iron
4/4
14,300-28,200
21,800.00
1,440-46,400
Manganese
4/4
155-382
240.50
7.6L-491
Notes:
J = Analyte was positively identified, value is estimated.
L = Analyte was positively identified, value is biased low.
ND = Not Detected
* The arithmetic mean is calculated using positive detections and one half of the detection limit for non-detections.
-------
TABLE A-12
SUBSURFACE SOIL STATISTICAL SUMMARY OF HUMAN HEALTH CHEMICALS OF POTENTIAL CONCERN
FROM SUBSURFACE SOIL SAMPLE ANALYSIS
SITE 7
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
RANGE OF RANGE OF
FREQUENCY DETECTED ARITHMETIC* STATION
OF CONCENTRATIONS MEAN BACKGROUND
CHEMICAL DETECTION (mg/kg) (mg/kg) (mg/kg)
Inorganics:

Aluminum
13/13
2,920-14,000
6,697.69
2,710-28,200
Antimony
2/13
10.5L-16.5L
5.53
8.5L- 31.3L
Arsenic
13/13
0.96K-14.S
3.71
0.23J - 42.7
Beryllium
11/13
0.27-1.7
0.64
0.3J-9.8
Chromium
13/13
4.8-63.4
17.7
5.2L- 33.5
Iron
13/13
4,110-46,100
14,155.38
3,810-51,100
Manganese
13/13
41.1-429
163.87
3.5J - 2,940
Notes:
J = Analyte was positively identified, value is estimated,
ft = Estimated value, biased high
L = Estimated value, biased low
* The arithmetic mean is calculated using positive detections and one half of the detection limit for non-detections.
-------
TABLE A-13
STATISTICAL SUMMARY OF HUMAN HEALTH CHEMICALS OF POTENTIAL CONCERN
FROM GROUNDWATER SAMPLE ANALYSIS
SITE 7
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
CHEMICAL
FREQUENCY
OF
DETECTION
RANGE OF
DETECTED
CONCENTRATIONS
(ng/L)
ARITHMETIC*
MEAN
(/ug/L)
RANGE OF
STATION
BACKGROUND
(jUg/L
Volaiilts

1,1-Dichloroethane
1/3
16
NC
—
1,1-Dichloroethene
1/3
4
NC
—
1,1,1 -Trichloroethane
2/3
2-40
NC
..
Nitrammes

4-Am ino-2,6- Dinitrotoluene
3/3
2.5-37
NC

RDX
3/3
13-180
NC
-
Inorganics (Dissolved)
Antimony
1/3
13.7
NC
18.5J
Notes:
J = Analyte was positively identified, value is estimated
NC« Not Calculated
* The arithmetic mean is calculated using positive detections and one half of the detection limit for non-detections.
-------
TABLE A-14
SURFACE WATER STATISTICAL SUMMARY OF HUMAN HEALTH CHEMICALS OF POTENTIAL CONCERN
FROM SURFACE WATER SAMPLE ANALYSIS
SITE 7 - STUDY (TRIBUTARY) AREA
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA

RANGE OF

FREQUENCY
DETECTED
ARITHMETIC*
STATION

OF
CONCENTRATIONS
MEAN
BACKGROUND
CHEMICAL
DETECTION

(pig/L)
(Mg/L)
Inorganics (Dissolved):

Arsenic (carc)
2/3
1.3-1.8
NC
1.2J - 13L
Notes:
J = Analyte was positively identified, value is estimated
L * Value is estimated; biased low
NC = Not Calculated
~ The arithmetic mean is calculated using positive detections and one half of the detection limit for non-detections.
-------
TABLE A-15
SURFACE WATER STATISTICAL SUMMARY OF HUMAN HEALTH CHEMICALS OF POTENTIAL CONCERN
FROM SURFACE WATER SAMPLE ANALYSIS
FELGATES CREEK
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA

RANGE OF

FREQUENCY
DETECTED
ARITHMETIC*
STATION

OF
CONCENTRATIONS
MEAN
BACKGROUND
CHEMICAL
DETECTION
(Mg/L)
O^g/L)
fcg/L)
Inorganics (Dissolved);

Manganese
9/9
36.7J-99.7J
69.79
21 • 290
Notes;
J
*
= Analyte was positively identified, value is estimated
The arithmetic mean is calculated using positive detections and one half of the detection limit for non-detections.
-------
TABLE A-16
SEDIMENT STATISTICAL SUMMARY OF HUMAN HEALTH CHEMICALS OF POTENTIAL CONCERN
FROM SEDIMENT SAMPLE ANALYSIS
SITE 7 - STUDY (TRIBUTARY) AREA
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
CHEMICAL
FREQUENCY
OF
DETECTION
RANGE OF
DETECTED
CONCENTRATIONS
(mg/kg)
ARITHMETIC*
MEAN
(mg/kg)
RANGE OF
STATION
BACKGROUND
(mg/kg)
Inorganics;

Aluminum
6/6
19,300-34,100
27,850.00
1,510-40,500
Arsenic
6/6
9.7-13.3
11.38
1.4J -13.1
Beryllium
6/6
1.1-1,6
1.38
0.55J- 1.6J
Chromium
6/6
42.5-61.5
53.07
3.8-66.1
Iron
6/6
39,100-45,500
42,316.67
3,060-46,000
Manganese
6/6
252-385
312
7.4 -1,980
Vanadium
6/6
52.1-69.2
62.48
4.8J-67.0
Notes:
J = Analyte was positively identified, value is estimated.
L = Estimated value, biased low.
* The arithmetic mean is calculated using positive detections and one half of the detection limit for non-detections.
-------
TABLE A-17
SEDIMENT STATISTICAL SUMMARY OF HUMAN HEALTH CHEMICALS OF POTENTIAL CONCERN
FROM SEDIMENT SAMPLE ANALYSIS
FELGATES CREEK
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
RANGE OF RANGE OF
FREQUENCY DETECTED ARITHMETIC* STATION
OF CONCENTRATIONS MEAN BACKGROUND
CHEMICAL DETECTION (mg/kg) (mg/kg) (mg/kg)
Inorganics:
Aluminum
12/12
13,700-38,500
24,441.67
1,510-40,500
Arsenic
12/12
6.7-14.9
10.11
1.4J- 13.1
Beryllium
12/12
0.88-1.6
1.19
0.55J- 1.6J
Chromium
12/12
29.4-59.8
45.88
3.8-66.1
Iron
12/12
25,100-43.800
35,091.67
3,060 - 46,000
Manganese
12/12
202-327
254.08
7.4-1,980
Vanadium
12/12
36.2-71.2
56.25
4.8J - 67.6
Notes;
J = Analyte was positively identified, value is estimated.
* The arithmetic mean is calculated using positive detections and one half of the detection limit for non-detections.
-------
APPENDIX B
ECOLOGICAL ECOC SUMMARIES
-------
TABLE B-I
STATISTICAL SUMMARY OF ECOLOGICAL CHEMICALS OF POTENTIAL CONCERN
FROM SURFACE SOIL SAMPLE ANALYSES
SITE 6 - IMPOUNDMENT AREA (ROUND ONE, ROUND TWO, AND SUPPLEMENTAL INVESTIGATION)
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
. ^ ' rsf -y
Range of
Detected / Arithmetic* Range of Station
Frequency of Detections^ Mean Background
Chemical Detection iusM. iUSMl
Semivolatiles

Benzo(a)anthracene
2/17
36J-150J
188.59
Benzo(a)pyrene
2/17
26J-120J
186.24
Benzo(b)fluoranthene
2/17
85J-120J
189.71
Benzo(g,h,i)perylene
2/17
35J-150J
188.53
Benzo(k)fluoranthene
2/17
10QJ-I10J
190
Chrysene
2/17
130J-150J
194.12
Fluoranthene
3/17
30J-420
203.82
Indeno( 1,2,3-cd)pyrene
2/17
33J - 160J
189
Phenanthrene
2/12
27J - 320J
195.17
Pyrene
3/17
27J - 240J
188.35
Nitramines

HMX
1/17
5,600
788.24
RDX
1/17
2,900
560.29
-------
TABLE B-l (continued)
STATISTICAL SUMMARY OF ECOLOGICAL CHEMICALS OF POTENTIAL CONCERN
FROM SURFACE SOIL SAMPLE ANALYSES
SITE 6 - IMPOUNDMENT AREA (ROUND ONE, ROUND TWO, AND SUPPLEMENTAL INVESTIGATION)
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
, , « 1ST V
Range of ' , '• ' "
Deteglcd / Arithmetic* Range of Station
Frequency of (JJetectioris} Mean Background
Chemical Detection fmg/ke) (me/kg) (me/kg)
Inorganics
Aluminum
12/12
3,770- 11,200
6,851.67
1,960-24,100
Antimony
1/9
I3.8L
6.08
2L-IIL
Beryllium
12/12
0.31-0.76
0.53
0.23J-0.93J
Chromium
12/12
8.8-32.6
17.56
2.6-33.5
Iron
12/12
5,570-23,900
15,087.5
1,44046,400
Lead
12/12
6.7-22.1 J
11.75
2.1-43.1
Mercury
1/12
0.09
0.03
0.05J
Nickel
10/12
3.8-15.9
7.12
3.8J-I2.5
Vanadium
11/12
8.7-25.8
15.86
5.2J-64.7
Zinc
12/12
21.5-63.3
37.56
3.2KJ-48.4
Notes:
NC Not Calculated
ND Not Detected
J Estimated value
K Estimated value, biased high
L Estimated value, biased low „ , , . , , .
~ The arithmetic mean is calculated using positive detections and one half of the detection limit for non-detections.
-------
TABLE B-2
STATISTICAL SUMMARY OF ECOLOGICAL CHEMICALS OF POTENTIAL CONCERN
FROM SURFACE WATER SAMPLE ANALYSES
SITE 6 - IMPOUNDMENT AREA (ROUND ONE AND ROUND TWO)
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
Range of Detection Arithmetic* Range of Station
Frequency of Concentrations Mean Background
Chemical Detection (^g/L) (^g/L) (/^g/L)
Nitramines
HMX
3/6
2.8-12
3.22
—
RDX
3/6
5.8-33
8.78

2,4,6-Trinitrotoluene
1/6
36
9.49
—
Inorganics

Aluminum
6/6
36.3 -17,900J
4,433.5
171J-5,600
Chromium
3/6
17.3-61.2
17.65
ND
Cobalt
2/6
6.9 - 11
4.65
5.3J - 8.5J
Copper
4/6
6.1-50.3
24.03 •
5.6J - 6.7J
Iron
6/6
514 - 45.000J
13,086.83
289J - 6,650
Lead
4/6
3.8 - 78.8J
28.57
1.2L-5.4L
Manganese
6/6
15.8-450J
154.00
33.1-379
Mercury
1/6
0.21
0.09
ND
Nickel
3/6
23.2J - 34.3J
18.47
19.8K - 55.5K
Zinc
6/6
83.6- 554
190.72
7.9J - 80.2
Notes:
J Estimated value
K. Estimated value, biased high
L Estimated value, biased low j .
* The arithmetic mean is calculated using positive detections and one half of the detection limit for non-detections.
-------
TABLE B-3
STATISTICAL SUMMARY OF ECOLOGICAL CHEMICALS OF POTENTIAL CONCERN
FROM SEDIMENT SAMPLE ANALYSES
SITE 6 - IMPOUNDMENT AREA (ROUND ONI, ROUND TWO, AND SUPPLEMENTAL INVESTIGATION)
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
Chemical
Frequency of
Detection
Range of Detection
Concentrations
(Mg/kg)
Arithmetic Mean*
(Mgftg)
Range of Station
Background
(Mg/kg)
Volatiles
Acetone
Carbon Disulfide
Chloroethane
Chloromethane
1.1-Dichloroethane
1.2-Dichloroethane
Tetrachloroethene
1,1,1 -Trichloroethane
Vinyi Chloride
SemivolatUes
Acenaphthene
Anthracene
Benzo(a)anthrecene
Benzo(a)pyrene
Benzo{g,h,i)perylene
Bis(2-ethylhexyl)phthalate
28/46
3/45
2/46
1/46
1/46
3/46
2/46
2/46
1/46
2/46
3/46
17/46
15/46
11/46
22/46
24J - 760J
12J-47J
15J-24J
16J
4.500J
8J ¦ 88,000
91 - 180,000
31 J - 190,000
140
240J - 440J
120J - 520J
94J- 2,100
150J- 2,000
130J- 1,600J
150J- 36,000
318.59
196.77
196.96
196.67
121.36
1,935.66
3,939
4,152.91
198.76
589.02
560.54
550.85
570.00
548.48
2,421.63
-------
TABLE B~3 (continued)
STATISTICAL SUMMARY OF ECOLOGICAL CHEMICALS OF POTENTIAL CONCERN
FROM SEDIMENT SAMPLE ANALYSES
SITE 6 - IMPOUNDMENT AREA (ROUND ONE, ROUND TWO, AND SUPPLEMENTAL INVESTIGATION)
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
Chemical
Frequency of
Detection
Range of Detection
Concentrations
tegfcg)
Arithmetic Mean*
(^g/kg)
Range of Station
Background
(^g%)
Carbazole
1/46
340J
574,02
--
Chrysene
17/46
1201 - 2,400
601.63
..
Dibenzo(a,h)anthracene
5/46
62J - 330J
539,5
..
Fluoranthene
18/46
79J-3,900
666.57
—
Fluorene
1/46
220J
570.41
--
Indeno( 1,2,3-cd)pyrene
10/46
170J - 1,800
566.74
..
2-Methylnaphthalene
3/46
210J - 450
557.17
--
4-MethyIphenol
1/46
1.500J
599.24
-
Pentachlorophenol
1/46
230J
1,413.59
-
Phenanthrene
15/46
llOJ-2,400
573.26
--
Pyrene
24/46
63J-4,000
679.85
—
Nitramines

4-amino-Dinitrotoluene
6/37
98N - 3.000N
429.03
~
2,4-Dinitrotoluene
1/46
28.0Q0J
1,125.11
—
2,6-Dinitrotoluene
1/46
550J
528.37
-*¦
HMX
2/46
96,000-710,000
18,040.23
—
RDX
2/46
63,000- 160,000
5,218.06
-
-------
TABLE B-3 (continued)
STATISTICAL SUMMARY OF ECOLOGICAL CHEMICALS OF POTENTIAL CONCERN
FROM SEDIMENT SAMPLE ANALYSES
SITE 6 - IMPOUNDMENT AREA (ROUND ONE, ROUND TWO, AND SUPPLEMENTAL INVESTIGATION)
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
Chemical
Frequency of
Detection
Range of Detection
Concentrations
(Mg/kg)
Arithmetic Mean*
(Mg/kg)
Range of Station
Background
(Mg/kg)
1,3,5-Trinitrobenzene
2/46
5,400- 19,000
861.97
..
2,4,6-Trinitrotoluene
8/19
130N-6,200
535.44
-
Inorganics

(mg/kg)
(mg/kg)
(mg/kg)
Aluminum
19/19
2.150J- 38,900
9,004.21
1,510-40,500
Arsenic
19/19
1.5 - 23,8
8.53
1.4J-13.1
Beryllium
12/19
0.33-1.7
0.76
0.5 5J-1.61
Cadmium
5/19
2.5 - 9.8
2.57
ND
Chromium
19/19
9.8-94.8
30.63
3.8-66.1
Cobalt
12/19
1.6-12.4
4.67
3.81- 15J
Copper
19/19
2.3 -130
29.62
3.7J-43.1
Iron
19/19
8,130-61,600
20,137.37
3,060-46,000
Lead
14/19
3.6J-68.1J
25.84
3.4-51.6
Manganese
19/19
10.7-245
90.68
292J-9.720K
Mercury
2/19
0.I2-0.22K
0.13
0.18L-0.29L
Nickel
16/19
4.9K -100
28.32
9.3K-55.2
Selenium
4/19
0.36L- 1.2L
0.59
0.46L-1.5L
Vanadium
19/19
9.2 - 382
96.78
4.8J-67.6
-------
TABLE B-3 (continued)
STATISTICAL SUMMARY OF ECOLOGICAL CHEMICALS OF POTENTIAL CONCERN
FROM SEDIMENT SAMPLE ANALYSES
SITE 6 - IMPOUNDMENT AREA (ROUND ONE, ROUND TWO, AND SUPPLEMENTAL INVESTIGATION)
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA

Range of Detection

Range of Station

Frequency of
Concentrations
Arithmetic Mean*
Background
Chemical
Detection
O^g)
(jUg^Cg)
(^g/kg)
Zinc
19/19
22.6 - 643
197.42
4J-202J
Notes;
NC Not Calculated
J Estimated Value
K Estimated value, biased high
L Estimated value, biased low
N Tentatively Identified Compound
* The arithmetic mean is calculated using positive detections and one half of the detection limit for non-detections.
-------
TABLE B-4
STATISTICAL SUMMARY OF ECOLOGICAL CHEMICALS OF POTENTIAL CONCERN
FROM SEDIMENT SAMPLE ANALYSES
SITE 6-FLUME AREA
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
Range of Detection Range of Station
Frequency of Concentrations Arithmetic Mean4 Background
Chemical Detection (^g/kg) (^g&g) (Mg/kg)
Volatiles

Acetone
in
64B-170
NC
--
1,1-Dichloroe thane
7/7
o
00
O
t
ci
NC
..
1,2-Dichloroethene (total)
7/7
42J - 110.000DJ
NC
-
Tetrachloroethene
3/7
9J-100J
NC
--
1,1,1-Trichloroethane
4/7
90 - 270
NC

Trichloroethene
7/7
21J - 2,600.000DJ
NC
..
Vinyl Chloride
6/7
29 - 4.000D
NC
-
Semivolatiles

Acenaphthene
4/7
80J-230J
NC
—
Anthracene
5/7
84J-410J
NC
—
Benzo(a)anthracene
6/7
99J - 1,200J
NC
—
Benzo(a)pyrene
in
490J-1,000J
NC
—
Benzo(g,h,i)perylene
4/7
160J - 850J
NC
—
Bis(2-ethylhexyl)phthalate
7/7
400J-5.500J
NC
-*
Carbazole
3/7
110J - 230J
NC
--
Chrysene
6/7
120J- 1.500J
NC
..
-------
TABLE B-4 (continued)
STATISTICAL SUMMARY OF ECOLOGICAL CHEMICALS OF POTENTIAL CONCERN
FROM SEDIMENT SAMPLE ANALYSES
SITE6-FLUME AREA
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
Range of Detection Range of Station
Frequency of Concentrations Arithmetic Mean* Background
Chemical Detection pig/kg) (^g/kg) (^g/kg)
Dibenzo(a,h)anthracene
1/7
140J
NC
Fluoranthene
6/7
2G0J - 2.000J
NC
Fluorene
5/7
87J-260J
NC
2-Methylnaphthalene
6/7
1,100J - 3.300J
NC
4-Methylphenol
6/7
93J - 530J
NC
Naphthalene
6/7
510J - 1,000J
NC
n-Nitrosodiphelamine
3/7
80J-210J
NC
Phenanthrene
6/7
270J-2.000J
NC
Pyrene
6/7
310J - 2.900J
NC
Pesticides

4,4'-DDD
2/7
16J-31J
NC
4,4'-DDE
3/7
26J-49J
NC
4,4'-DDT
1/7
16J
NC
NUramine/Nitroaromatic

Compounds

2-amino-4,5-Dinitrotoluene
5/7
7.400J - 600,000
NC
4-amino-Dinitrotoluene
5/7
4.800J-640,000
NC
-------
TABLE B-4 (continued)
STATISTICAL SUMMARY OF ECOLOGICAL CHEMICALS OF POTENTIAL CONCERN
FROM SEDIMENT SAMPLE ANALYSES •
SITE 6-FLUME AREA
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA

Range of Detection

Range of Station

Frequency of
Concentrations
Arithmetic Mean*
Background
Chemical
Detection
Og/kg)
0«g/kg)
(Mg/kg)
2,4-Dinitrotoiuene
4/7
580J - 3.700J
NC
—
2,6-Dinitrotoluene
2/7
320J - 590J
NC
-
HMX
in
3.300J - 45,000
NC
~
RDX
6/7
2.100J- 120,000
NC
--
1,3,5-Trinitrobenzene
2/7
610J- 6,800
NC
~
2,4,6-Trinitrotoluene
6/7
870J - 1,000,0000
NC
-

Range of Detection

Range of Station

Frequency of
Concentrations
Arithmetic Mean*
Background
Chemical
Detection
(mg/kg)
(mg/kg)
(mg/kg)
Inorganics

Aluminum
7/7
2,680-10,500
NC
482K- 17.700J
Arsenic

6.7J - 27.4J
NC
0.27L - 5.4L
Beryllium
in
0.16-1.2
NC
0.28J - 0.99J
Cadmium
7/7
3.6K- 15.8K
NC
ND
Cobalt
7/7
1.3-9.4J
NC
1.IJ-7.9J
Copper
7/7
53.1J-227J
NC
1J - 6.3 J
Cyanide
4/7
0.75-1.3
NC
ND
-------
TABLE B-4 (continued)
STATISTICAL SUMMARY OF ECOLOGICAL CHEMICALS OF POTENTIAL CONCERN
FROM SEDIMENT SAMPLE ANALYSES
SITE 6-FLUME AREA
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
Chemical
Frequency of
Detection
Range of Detection
Concentrations
C^g&g)
Arithmetic Mean*
(^g/kg)
Range of Station
Background
(^g/kg)
Iron
7/7
11,7001 -3l,300J
NC
329 - 27.700J
Lead
7/7
68.8-220
NC
I.8L-38IL
Mercury
6/7
0.1-0.96
NC
0.06L - 0.09L
Nickel
7/7
6J - 232J
NC
4.6K- I7.5K
Selenium
3/7
1.3-1.9
NC
0.86L
Vanadium
7/7
20.9J- 1.250J
NC
1.9J-38.9
Zinc
7/7
185K- I.000K
NC
3.2J-143
Notes:
NC Not Calculated ,
ND Not Detected
D Sample required dilution
J Analyte was positively identified, value is estimated
K Estimated value, biased high
L Estimated value, biased low
* The arithmetic mean is calculated using positive detections and one half of the detection limit for non-detections.
-------
TABLE B-5
STATISTICAL SUMMARY OF ECOLOGICAL CHEMICALS OF POTENTIAL CONCERN
FROM SURFACE WATER SAMPLE ANALYSES
SITE 6 - TRIBUTARY(ROUND TWO)
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA

Range of Detection

Range of Station

Frequency of
Concentrations
Arithmetic Mean*
Background
Chemical
Detection
(*g/L)

<^g/L)
Inorganics

Aluminum
4/4
491 -1,130
851
171 J- 5,600
Iron
4/4
1,200-1,530
1,402.5
289J - 6,650
Manganese
4/4
53.2 - 86.1
72.8
33.1-379
Nickel
2/4
19.8-49.6
21.35
I9.8K - 55.5K
Notes:
J Estimated value
K Estimated value, biased high
* The arithmetic mean is calculated using positive detections and one half of the detection limit for non-detections.
-------
TABLE B-6
STATISTICAL SUMMARY OF ECOLOGICAL CHEMICALS OF POTENTIAL CONCERN
FROM SEDIMENT SAMPLE ANALYSES
SITE 6 - TRIBUT ARY (ROUND TWO)
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
Chemical
Frequency of
Detection
Range of Detection
Concentrations
(^g/kg)
Arithmetic*
Mean
(^g/kg)
Range of Station
Background
(Mg%)
Volaiiles

Acetone
6/8
27J - 220J
94.56
—
Carbon Disulfide
2/8
I2J- IIOJ
26.69
—
Semivolatiles

Phenol
1/8
890J
534.38
--
Inorganics

Aluminum
8/8
9,430 - 33,300
24,528.75
1,510-40,500
Arsenic
8/8
4.5-11.2
8.74
I.4J-13.1
Beryllium
7/8
1.1 - 1.5
1.13
0.55J- I.6J
Cadmium
1/8
2.4
1.66
ND
Cobalt
8/8
2.6- 12.5
8.46
3.8J- 15J
Iron
8/8
* 19,000-39,900
34,000
3,060 - 46,000
Manganese
8/8
67.1-286
213.01
7.4-1,980
Nickel
8/8
13.4-36.1
27.01
9.3K. - 55.2
Vanadium
8/8
37.2-81.9
59.96
4.8J - 67.6
Zinc
8/8
79.6- 153
131.45
41 - 202J
Notes:
ND Not Delected
* The arithmetic mean is calculated using positive detections and one half of the detection limit for non-detections.
-------
TABLE B-7
STATISTICAL SUMMARY OF ECOLOGICAL CHEMICALS OF POTENTIAL CONCERN
FROM SURFACE SOIL SAMPLE ANALYSES
SITE 6 - EXCAVATED AREA (ROUND TWO)
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
Range of Detection Arithmetic* Range of Station
Frequency of Concentrations Mean Background
Chemical Detection (mg/kg) (mg/kg) (mg/kg)
Inorganics
Aluminum
6/6
13,I00J- 27,0001
19,550.00
1,960 - 24,100
Antimony
1/6
11.9L
6.49
9.2L- 11L
Beryllium
6/6
0.47 - 0.82
0,64
0.23J - 0.93J
Cadmium
2/6
3.4L - 18.4L ,
4.09
1.2J-1.5
Chromium
6/6
20.1 -52.2
36.77
2.6-33.5
Iron
6/6
14.400J-35.300J
24,433.33
1,440-46,400
Lead
6/6
9 6K-43.1K
25.55
2.1-43.1
Nickel
5/6
4.6L - 9.2 L
6.36
3.8J - 12.5
Vanadium
6/6
25 - 53.6
40.22
5.2J - 64.7
Zinc
6/6
93.1J-2.340J
934.18
3.2KJ - 48.4
Notes:
J Estimated value
K Estimated value, biased high
L Estimated value, biased low
~ The arithmetic mean is calculated using positive detections and one half of the detection limit for non-detections.
-------
TABLE B-8
STATISTICAL SUMMARY OF ECOLOGICAL CHEMICALS OF POTENTIAL CONCERN
FROM SURFACE SOIL SAMPLE ANALYSES
SITE 7 - STUDY AREA (ROUND TWO)
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
Chemical
Frequency of
Detection
Rj|PgfOgtoted Arithmetic*
Vjjfcteuiyiw-- (oner* - Mean
(mg/kg) (mg/kg)
Range of Station
Background
(mg/kg)
Inorganics

Aluminum
4/4
6,010- 19,100
13,552.5
1,960 - 24,100
Antimony
1/4
18.6L
8.09
9.2L- 11L
Beryllium
4/4
0.48-0.95
0.72
0.23J - 0.93J
Cadmium
1/4
6
1.96
1.21 - 1.5
Chromium
4/4
13.7-40.2
29.88
2.6-33.5
Copper
4/4
4.4- 145
41.73
1.2J-24.4
Cyanide
1/4
1.2
0.57
ND
Iron
4/4
14,300-28,200
21,800.00
1,440-46,400
Lead
4/4
8.9K-148
49.00
2.1-43.1
Manganese
4/4
155-382
240.50
7.6L-491
Mercury
3/4
0.08 - 0.53
0.18
0.05J
Nickel
4/4
11.5-27.2
17.65
3.8J - 12.5
Vanadium
4/4
20.6-43J
35.95
5.2J - 64.7
Zinc
4/4
25.3 - 928
270.80
3.2KJ -48.4
Notes: •
ND Not Detected * The arithmetic mean is calculated using positive detections and one half of the
J Estimated value detection limit for non-detections.
K Estimated value, biased high
L Estimated value, biased low
-------
TABLE B-9
STATISTICAL SUMMARY OF ECOLOGICAL CHEMICALS OF POTENTIAL CONCERN
FROM SURFACE WATER SAMPLE ANALYSES
SITE 7 - TRIBUTARY (ROUND TWO)
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA

'
Range of Detected

/ ¦
Range of Station

Frequency of '
UttiUvliwii3/r
Arithmetic Mean*
Background
Chemical
Detection
Ml)
(mb/L)
(MS/L)
Inorganics

Aluminum
m
841 - 1,460
1,088.67
171 J. 5,600
Iron
3/3
1,090-1,870
1,403.33
2891-6,650
Manganese
3/3
79.7-87.5
83.6
33.1 -379
Notes:
J Estimated value
~ The arithmetic mean is calculated using positive detections and one half of the detection limit for non-detections.
-------
TABLE B-IO
STATISTICAL SUMMARY OF ECOLOGICAL CHEMICALS OF POTENTIAL CONCERN
FROM SEDIMENT SAMPLE ANALYSES
SITE 7 - TRIBUTARY (ROUND TWO)
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
Chemical
Frequency of
Detection
RangefllDetected^^ Range of Station
'Dete'ctronT>>> Arithmetic Mean* Background
—iasMl j
Volatile*
Acetone
Carbon Disulfide
Semivoiatiles
Di-n-Butylphthalate
6/6
1/6
1/6
25J - 300J
66J
2,700
143.33
25,50
879.17

Frequency of
Ranged Detected >

Range of Station

Detection
(Detectionsj^
Arithmetic Mean
Background
Chemical
(mg/kg)
^(mpi)
(mg/kg)
(mg/kg)
Inorganics

Aluminum
6/6
19,300-34,100
27,850.00
1,510-40,500
Arsenic
6/6
9.7-13.3
11.38
64)-13.1
Beiylltum
6/6
1.1 - 1.6
1.38
0.55J- 1.6J
Cobalt
A/6
7.9-11.5
10.12
38J - I5J
Iron
6/6
39,100-45,500
42,316.67
3,060-46,000
Manganese
6/6
252 - 385
312.00
7.4-1.980
Nickel
6/6
28.5 - 40.9
32.65
9.3K, - 55.2
Silver
2/6
2.4-3.1
1.84
2.2J
Vanadium
6/6
52.1 -69.2
62.48
4.8J - 67.6
Zinc
6/6
131-154
146.00
4J - 202J
Notes:
ND Net Detected
K Estimated value - biased high
~ Tb<* arithmetic mean is calculated using positive detections and one half of the detection limit for non-dcieciions.
-------
TABLE B-ll
STATISTICAL SUMMARY OF ECOLOGICAL CHEMICALS OF POTENTIAL CONCERN
FROM SURFACE WATER SAMPLE ANALYSES
FELGATES CREEK (ROUND TWO)
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA
Chemical
Frequency of
Detection
RangeofDeteeted
l5«totionsV''
(nm
Arithmetic Mean*
(nefL)
~ - • v
Range of Station
Background
(Mg/L)
Inorganics

Aluminum
9/9
433J- 1,3601
854.89
17U- 5,600
Cobalt
1/9
4.6
2.29
5.3J - 8.5J
Iron
919
8I0J- 1.980J
1,319.79
289J - 6,650
Manganese
9/9
98.4J- 168J
137.71
33.1 -379
Nickel
3/9
2l.2K-27.8K
13.18
I9.8K- 55.5K
Notes:
J Estimated value
K Estimated value, biased high
* Hie arithmetic mean is calculated using positive detections and one half of the detection limit for non-detections.
-------
table B-12
statistical summary of ecological chemicals of potential concern
FROM SEDIMENT SAMPLE ANALYSES
FELGATES CREEK
NAVAL WEAPONS STATION YORKTOWN
YORKTOWN, VIRGINIA

Range of Detection
Arithmetic*
Range of Station

Frequency of
Concentrations
Mean
Background
Chemical
Detection
(^fg/kg>
C/^kg)
(,Mg/kg)
Volatile*

Acetone
3/12
26J - 160J
34.08
—
Semivolatiles

Di-n-Butylphthalate
7/12
3,500- 16,000
3,748.33
-

Range of Detection
Arithmetic
Range of Station

Frequency of
Concentrations
Mean
Background
Chemical
Detection
(mg/kg)
(mg/kg)
(mg/kg)
Inorganics

Aluminum
12/12
13,700-31,500
24,441.67
1,510-40,500
Arsenic
12/12
6.7-14.9
10.11
I.4M3.I
Beryllium
12/12
0.88- 1.6
1.19
0.55J-1.6J
Cobalt
12/12
7.7-12.2
9.83
3.8-66.1
Iron
12/12
25,100-43,800
35,091.67
3,060-46,000
Manganese
12/12
202 - 327
254.08
7.4-1,980
Mercury
1/12
0.3 IK
0.13
0.I8L-0.29L
Nickel
12/12
13-37.9
23.53
9.3K-55.2
Selenium
7/12
0.63L- 2.5K
1.05
0.46L-I.5L
Vanadium
12/12
36,2-71.2
56.25
4.8J-67.6
Zinc
12/12
99.7J- 172J
131.23
4J-202J
Notes:
J
K
L
Estimated value * The arithmetic mean is calculated using positive detections and one half of the
Kstimated value, biased high detection limit for non-detections.
Estimated value, biased low
-------
APPENDIX C
PUBLIC MEETING TRANSCRIPT
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MOM IMfflB.
NAVAL WEAPONS STATION
YORKTOWN
PROPOSED REMEDIAL ACTION PLANS FOR
SITES 1 & 3 and SITES 6 & 7
TRANSCRIPT OF PROCEEDINGS
Yorktown, Virginia
March 26, 19 9 8
Appearances:
Jeff Harlow, Weapons Station Yorktown
Rich Hoff, Baker Environmental, Inc.
Scott Park, LANT Division
Bob Stroud, U.S. EPA, Region 3
TAYLOE ASSOCIATES, INC.
Registered Professional Reporters
Telephone: 1757} 461-1984
Norfolk, Virginia
TAYLOE ASSOCIATES, INC.
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PROCEEDINGS
KAYE PHILLIPS: I'm Kaye Phillips, public
affairs officer. 1 replaced Tom Black juac about a
year ago, and ao it's nice seeing all of you here
tonight. And captain -- I almost goofed there.
Captain Denham is here with us. He's our commanding
officer for the station. And Jay Dewing is our
chairman for us -- cochaicman,
Captain, did you have anything you wanted
to say?
CAPTAIN DENHAM; No, I don't have
anything. Go ahead.
KAYE PHILLIPS: Jay?
JAY DEWING; Not until later.
KAYE PHILLIPS-. Okay. If any of you
noticed in Sunday's paper, we had the ad that's
running that's required for 4S days regarding this
proposed remediation plan that's coming up for Sites :
and 3 and 6 and 1. It started on the 2 6th of May.
And the period will run from 10 July and any -- that'
open for public comments. And all comments would be
sent to my office, and then I turn it over to Jeff an
these gentlemen that are working on this program.
Tonight,, Jeff, along with -- we have Boh
Stroud, who is new. I think it is his first official
TAYLOE ASSOCIATES, INC.
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meeting.
BOB STROUD: Second.
KAYE PHILLIPS: Okay. But Bob was still
here the last time, right?
BOB STROUD: No, he wasn't here.
KAYS PHILLIPS: But Bob replaced Rob and
he's hare with us Crom EPA. And Scott Park and Rich
will be working with Jeff in making his presentation
tonight.
If any of you know anyone in the
community that has any comments or anything to make
regarding these, my phone number is -387-4939. That's
in the ad that's in.the paper. And, please, Eeel free
to call me, and we'll get the information for you
that's desired.
So without anything further, I'm going to
turn it over to Jeff. And I will mention that I think
there's been some question about budget that wasn't on
your agenda, but that will be covered before the close
of the program this evening.
JEFF HARLOW; I guess first thing is we
tried to * incorporate this public meeting type scenario
in with the RAB meeting. I'm interested in comments
if you'd like to do this or we can take the technical
stuff. I kind of thought this might be a quick way to
TAYLOE ASSOCIATES, INC,
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4
get up to speed to what's going on here in the next
year or so at the station.
But, again, if we don't like this, we can
change the format to just have a separate public
meeting, just trying to save a little money and work
it in. The trade-off of that is, ia that, you know,
we're sacrificing some of our RAB time far it., And
then the other thing is we get in a pinch that we've
scheduled so far ahead that when we announced the
meeting, we were kind of set to do it; whereas in the
past, we probably allowed for a couple of weeks for
the announcement to hit the paper and then actually
had the public presentation.
And I guess with that, what I'm going co
do is we're going to do this as a joint effort like
Kaye was saying. I'm going to let Bob pick up. He is
new to the sites, but he's getting on board real quick
and has been a big asset, as far as I'm concerned, anc
he's got the first four slides here for ua to get us
started, and then I'm going go into the site
descriptions and then Scott and Rich will follow it u
on the back end.
BOB STROUD: Good evening. I guess
you-all know, my name is Bob Stroud. I'm the new EPA
project manager for Yorktown. I've been involved wit
TAYLOS ASSOCIATES, IMC.
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5 |
the sites for about six months or so. My first
meeting was in December of *97. What we want to try
and do tonight is present to you the proposed remedial
action plana for four different sites at Yorktown,
Sites 1 and 3 and Sites-€ and 7. Actually, I'm
probably going to be repeating what Jeff and Kaye just
said.
Okay. This presentation to this meeting
Is to just let all concerned citizens know that
Yorktown is going to be evaluating the four sites that
I've mentioned, Sites 1 and 3 and 6 and 7. And as
Kaye had mentioned to you, the public comment period
begins today. May 25, and continues for 45 days,
through July 10th, 1998. So if anyone has any
comments, suggestions, or concerns, they can contact
Kaye, I guess, by letter or phone or what have you.
This slide here just represents a
couple -- actually, this is the entire facility. This
map here represents the entire facility, with this
being Felgates Creek in this area and this being
Indian Field Creek. Sites 1 and 3 and 6 and 7 are in
these two areas right here. I think the next slide
shows it.
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3. The reason chat we're doing them together like
this ia because of their location. Since they are
located, so close to each either, it just makes sense
in saving money and that sort of thing, to do these
sices together.
With that, I'll turn it over to Jeff
Harlow.
JEFF HARLOWs 1 Okay. I get to do site
description since I'm Che resident expert, I guess.
We'll do Site 1 first. Ultimately it was a landfill
at the station from 19SS through just beyond 1979. It
operated under a conditional use permit. And a little
note here for lens grinding dust, we have had a
lieutenant command on our site, generally they make
all the lenses -- or all the glassware for all the
military. I think the Army closed their facilities
down, and it's a pretty big business there.
But at one time they were dumping their
lens grinding dust in our landfill, pretty much an
inert plastic material.
This is Site 1 specifically, the entrance
point down here in the bottom of the slide.
Generally, all the debris Is in this area here on the
right-hand aide of this access road that you see
here. It's kind of a typical scenario, I guess, for
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landfills in the past. This was once a borrow area
for sand and fill. They had a hole. What do you do
with a hole? You fill it back in, and ie became a
landfill.
You see a small ponded area here. Word
on it was it was an excavated area that fust never got
filled. It dries up in the summertime. And you see a
green patch. It's kind of a little wildlife
management area. It's beyond the boundaries of the
landfill itself. Indian Field you're seeing here in
the background right here.
Site 3 is a two-acre dump area, same
thing. This one is even older than Dudley Road
Landfill. It'a been real difficult to even get --
except this document only speculates that it was used
in the early 1900s as a fill area for us developing
our industrial area, h lot of cuts, you know, steep
walls and stuff where it just looks like they're in
there raining out the fill for using somewhere else.
Ultimately the same thing came down, you
had a hole in the ground and what to do with it but
try to fill it back in.
This is Site 3 looking at the main roads
here. Putting some perspective, Dudley Road Landfill
would be down here at the bottom. You can't see the
**** %ry
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pointer very good down here. And the beginning of
Indian Field Creek, or at least one of the branches,
would kind of run between the two sites. And
ultimately Indian Field would run down here at my feet
or whatever. You're seeing some of our magazines here
in the background.
Here's a perspective of the two sites
together. Here you're seeing Dudley Road Landfill.
And back; in here you can kind of see some reduced
growth. That's the landfill here, And then
ultimately Felgatea Creek coming out this way.
Site 6 -- and what we're doing -- I'm
just going to back up here. We're actually
incorporating both of these perhaps together in one
presentation. So l and 3 is the first one. We're
doing those two sites together as one unit. And
ultimately you'll see a rod for those two sites.
And now for Sites 6 and 7, there will be
a separate rod for that, and I just wanted to break
chat out so we can work it all in one presentation.
Site 6 is a washout facility, basically
there since 1942-43. It's always been a reclaim
facility for TNT. We did install a carbon, absorption
tower in 1975 which theoretically should have
alleviated the waste that we would have baea putting
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in Che creeks.'
And Chen ultimately we hooked up HRSD,
and we've been knocking this around. I have to do a
little more research, but I thought it was the early
•80s. We're saying '86. That's the beat we have as
of right now.
There's also -- along with some of the
cooperative efforts with EPA, they had some
considerable concerns with the actual building itself
being contaminated, potentially the contaminants
migrating out into the facility. And so we're also
looking at some of the trenches and stuff inside the
building. It won't be a perfect clean closure of a
building, but at least we'll negate any potential for
the building itself contaminating out in the
environment.
We then in the future have schedules to
do building demolition under the MIL COM program where
it should appropriately be done.
This is building 109. You see here in
the shadows a little bit, you see the trench here that
went out into, what we call now, the impoundment
i
area. There's a dam or what -- the impoundment here
that you see. And you don't see it on here, but it's
along this general area. And all of that wastewater
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went out from this die ch inco thi3 marshy .
There's another thing with this site o££
to Che aide here, there's an annex that had a vapor
phase degreaser in there and some TCU problems here on
the site along with some explosives. This was a
second phase. I guess this building generally went
through two improvements, I guess, or modifications.
And this equipment went in the early '40s and then it
went through -an upgrade.
At one time there was a tank inside this
building that actually they did TCE liquid solution
and decreasing or actually tar removal o£ the lining
material inside the bomb casings. And what 1
understood what they do is when it got dirty, you'd
open up the valve and out in the creek it would go.
This is looking back cowards Building
109, and you can now see the impoundment itself here.
It was also ~~ just to put a time line, it was built
at the same time the building was built, in 1942.
As far as the whole area here - - and I
guess Rich will get more into it, but the impoundment
itself is not really showing any large amounts of
explosive contamination. We're seeing it right at th-
edge of the trench, right at the end of it.
And, of course, in the proposal we're
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going co look at just doing long-term monitoring to
see where it's at instead of destroying the ^fttlanda
to see what might be out there.
Here you're seeing a view from the
building and the trench here going out into the
marsh. That concludes 6. And I'll go into 7.
Now, 7 was our actual explosive loading
plant three. You had a loading facility- You lead
weapons or casings of bombs, and whatever you had at
the end of the day, you'd have washdown procedures,
whether it be the kettle or just the building itself.
Before 1975, that wastewater went right directly into
the creek.
After 1975 it, at least, went through
carbon tower, and then ultimately we went to HRSD.
All of these -- and just to reiterate, all of these
buildings for both 6 and 7 are aince closed, 109 has
been closed since the mid '80s. And plant two, I
guess, closed about three years ago or two and a half
years. And so that's where we're at on that.
This would be a view of plant three
here. Just a quick overview, you had the prep
building where your empty casings would come in. This
was the actual loading facility here. You did remote
loading. During the actual loading process, you'd be
Tivf.r>p *ce
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in. the bunkers and actual ly be loading remotely. And
that discharge water came out the building right
here. And you see like a »- hese it's hard to sea,-
we'll get to a few slides down in the bottom of this
presentation, but there's a run of rip rap here.
We did a removal action a couple of years
ago, and that's the biocell or bioslurry job that we
did. And I don't want to steal Rich's thunder here,
but essentially we succeeded in doing a good
treatability study so we don't have to go back out
here and clean this thing up.
And with that -« who ia it, Scott or
Rich?
RICK HOFP: What we're going to do
tonight ia a much more linear presentation of the
remedial action plan for these sites because of the
number of sites we have. In the past we have come in
here and we've discussed in detail the analytical
data, the risk assessments, and the evaluation of all
p£ the proposed remedial actions.
we thought in order to keep it a little
shorter and open it up for questions, that we would
run through this information in a little more
streamline manner. That was based on comments we
received from SPA Region 3. We've given these
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presentations to their hierarchy. And one of their
recommendations was to streamline the process and get
more information out to you-all quicker.
I'm going to start with Sites 1 and 3,
Scott will take 6 and 7.
As a recap, remedial invest igat ions were
performed at bath Sites 1 and 3. That included both
Round 1 RI and, a Round 2 remedial investigation. Data
that was collected during these investigations were
compiled into a focused feasibility study.
we did a focused feasibility study rather
than a full-blown feasibility study because the areas
of contamination in both sites were rather small. In
fact, the first time we did a proposed plan, we were
suggesting no action at both sites.
But because of the partnering process
that we're involved in, we've been able to sit down
with the regulators and really dissect the
information. And there were some concerns that came
out of it, the least of which is not the state's
concern about Site 1 and the fact that it was a former
solid waste limited landfill.
There were some findings that there were
low-lying areas that needed to be filled in. And so
when we went through, the process, we wanted to focus
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on those technologies that would supplement che
reastablishment of the cupboard.
I also wanted, to mention that EPA
Region 3 is going to be doing a comprehensive surface
water investigation at Indian Field Creek and Felgates
Creek in the next few months. And because of the
interconnectedness between groundwater and surface
water in Indian Field Creek, we didn¦t want to
evaluate any remedial alternatives at this time for
those media. So this focused feasibility study really
concentrated on the aoils in both Site 1 and Site 3.
This is one.of our worst figures. I
apologize for the quality of it. But this is Site 1
and here's Site 3. You saw through the pictures that
there was a ravine or a ditch that sort of bisected
the two, and then you enter one of the branches, one
of the two branches of Indian Field Creek on either
side of Site 3.
To evaluate the human health and
ecological risks, when we conducted the risk
assessment, there were really no unacceptable risks.
Current receptors, again no unacceptable risks.
Because of the frequency of exposure, it's rather
limited.
Future receptors. The concentrations
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when averaged over a large area really didn't give us
much of an average or an upper 95th percent: that we
would have Co worry about. But.there were some hot
spots.
The terrestrial and aquatic receptors
under the ecological risks is one of the few sites
where we had no really significant ecological
concerns.
When we were doing the focused FS, there
were one or two locations around Site l. In face,
they were well-boring locations that had high arsenic
concentrations. And by "high," I mean they were above
station-wide backdrops, which is about S3 parts per
million.
And we did some additional systest
sampling to figure out what the extent of this was,
and we also tried to get to the bottom of why there
might be this increased arsenic concentration. But we
never really figured out the latter, but we did take
additional samples, quite a number of them, to define
the hot spot. And we used 63 parts per million and
above as a way of incorporating the hot spot and
evaluating the extent of potential contamination.
And, again, the solid waste landfill
cover will be reestablished as part of the remedy.
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It's not really a risk-driven action, but, again, it's
out there and we wanted to address it aa part o£ the
remedy.
At Site 3, again with current receptors,
there were ao unacceptable health risks. Future
receptors, there were some unacceptable risks for
adult and children. And this was based on another hot
spot. And at Site 3 we had PAHs. And if you remember
the site description for Site 3, you saw a lot of
oils, greases, sludges, and solvents that went in
there. And this is, in fact, what we're turning up;
those PAHg are usually a constituent of those types of
waste materials.
True to form, the terrestrial
demonstrated a slight risk again to the PAHs. And the
aquatic, with the limited data that we had on Indian
Field Creek, there was-no significant risk present.
Again, I want to state that EPA is going to be
collecting additional data, and that's one of the
reasons we don't want to make any comments on the
aquatic, Indian Field Creek, and the groundwater at
this time.
This is, again, kind of difficult to see,
but if you take a look at Site l, we have an area of
debris that we're going to pick up. This is the
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extent of the arsenic hoc spot. It's very small. And
what's interesting is it's really off of the main body
of what was considered to be the solid waste
landfill. So to my knowledge, we really have no idea
as to why that arsenic exists there. But sure enough
when we take those samples, that area is well in
excess of all the other areas' at Site l.
Site 3, again the same situation, where
there are a number of debris piles that we have
identified. This is what we consider the extent of
Site 3 proper. And the small red area in the center
is•the area of soil that we're concerned about. This
was identified and delineated using PAH test kits down
to a depth of four £eee, and we have a very good
handle on the extent of contamination.
To wrap it up, we're proposing remedial
action three, and there are a number of remedial
actions proposed for each site, and I would encourage
you-all to take a look at the total remedial action
plan for the details associated with each one of the
RAAs and the associated costs.
We're proposing at this point in time to
reestablish the soil cupboard at Site 1, to do the
debris removal, and to do the soil excavation and
off-site disposal in the area of the arsenic hoc
vrftp ReenrTiiTue rwn
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spot. one of the reasons this was a focused fs is
chat: with such a small volume, it really doesn't make
sense to develop techniques such as in situ
vitrification or any of the in situ technology that
might be out there. It really wouldn't be cost
effective.
Site 3 we selected RAA-4, and it's very
similar. We're going to remove the debris that exists
in the area and we're going to excavate the PAH hot
spot. And, again, because of the limited size, we're,
going to off-site disposal. And this will bfe disposed
of as nonhazardous. We have to do TCLP to confirm
that. But, again, you're talking about such a small
area that it really doesn't make sense to look at any
land finding or compost technologies. And the present
work for this remedial action, the alternative is
155,000.
With that, I'd like to turn to Scott and
he'll tell you a little bit about 6 and 7.
SCOTT PARE: Okay. Moving over to Sites
6 and 7. Again, like. Sites l and 3, we conducted
remedial investigations and post: RI investigations at
each of those sites. And then a feasibility study
report evaluated the data collected from those
investigations and also took a look at our remedial
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action alternatives.
Again, we screened many and broke it down
to about six or seven, and I'll present to you which
one we came up with as our selection and that we're
proposing, again in the proposed remedial action plan,
that you can. review.
Sites S and 7, the -- let's see.
Operable Unit 14 is the whole area that bounds -- runs
along Felgatea Creek. Site 6 is generally in this
area. That's the building Jeff showed you. Here'a
the drainage way from that building and the large
impoundment that he showed to you. Site 7 is down
here. And you'll get some aits pictures of those.
Site 7 is Operable Unit 12. And Operable
Unit 13 is the flume area or drainage way leading from
Building 109 out towards the surface impoundment. And
then Operable Unit IS is an, excavated area. I'll talk
about that a little bit more and why it's there, what
we're doing with it.
Based on risk assessment summaries,
conclusions from Site 6 first were unacceptable risks
to human health from future residential exposure to
the soil and sediment in the impoundment area. Highly
unlikely that it will be developed for future
residential, but the possibility, I guess, does exist
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and there are some risks to doing that.
Unacceptable ecological risks to
receptors XIX & 1x6 impoundment ar^a, the flume area, and
che excavation areas, those are called areas of
concern. But actually the flume area is AOC, or Area
of Concern 1, the impoundment area is Area of Concern
2, and the excavation area is Area of Concern 3.
You'll see a picture of all of those.
Site 7 conclusions were there were no
unacceptable risks to human receptors under any
land-use scenario, no unacceptable ecological risks,
and all the risks were mitigated by the removal action
conducted for the full-scale pilot study. Jeff talked
about that.
Soil was removed and was taken to our
biotreatment cell where it was put into a slurry using
che simplex saber technology, and that's" been cleaned
up. And we're also using that cell right now to clean
up Site 19 which is another site we have evaluated and
moved to Rodham (phonetic).
This is a picture of Site 7. I'll cover
that first since it was basically taken care of
already. This is the area of concern that was cleaned
up. This is a little before my time. These guys can
help me out. I believe this material here is gravel
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chat was placed, down after the excavation Cook place
juse Co show a level where we had excavated to if 4c
ever came back later and somebody had to 30 back down,
they would know the area that had been taken care of.
This is just a grading of that area and
" regrading it, and it wasn't ravegecated, but it is
starting to vegetate itself, I believe. It's a low
spot down by Site 7,
Areas of Concern 1 and 2. First, again
the building ia down in this area and there's the
drainage way coming out of the building that leads out
towards the impoundment. There's a concrete channel
-- a system of channels underneath the building and
then a channel that leads wastewater out into the
flume area, as we call it, and then further along into
Area of Concern 2, which is ri ght here. That's the
impoundment area.
As Jeff mentioned, most of the
contamination that was found that had risks associated
.with it was right in this area, Area ,o£ Concern 1.
And that's the area that we're focusing our actual
cleanup, if you will, as I'll tell you about in our
remedial action alternatives.
This is AOC-3. It's an excavated area,
very uniform and rectangular a® you can see. We're
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2 2 I
riot really sure where chat came from. We don't know
if it's a basement for a house or a building or a
borrow area. I don't think tea a house, but it Looks
more like something like a borrow area or something .
somebody was getting ready to construct and. they never
4 did. And it's just an area that's there, and actually
we're just going to fill that in and cover it. And we
haven't found any risks associated with that.
The selected remedial alternative for
Sites 6 and 7. Site S, again, many were considered.
We're proposing in situ biological treatment using a
different biological treatment than the Simplot
process.
In our last meeting we discussed a joint
venture we're working.on with w.R. Grace and the
Canadian government, and we're looking for split
funding from both of those two entities, and the Navy?
the three of us are going to share-coat that. we're
in the treatability study phase right now, and it's
going well. If we have full proof that the technology
works, that's what we're proposing to use. It will be
a land farming treatment on the station and it will be
in a greenhouse type of structure.
And we'll clean up about a thousand cubic
yards of material, is what we're expecting right now.
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That's from our Area of Concern 1. There will be a
soil cover area in Area of Concern 3 which was
excavated, chat: we're not quite .sure where chat hole
came from.
Also as part of the project, we're going
"to do sludge removal from the channel system
underneath the building and the channel running out to
Area of Concern 1. And that will remove all the
contaminants and residual contaminants from operations
in that building so we can then block off the channel
from the building out to our site. And that way in
the future if any water were to get in the building or
anything came out from those channels, it would be
clean because we had already taken care of it; we
wouldn't recontaminate our site.
Then we*11 do long-term monitoring of
surface water and groundwater in the entire area.
And, again, Jeff had said the Area of Concern l was
our primary area of contamination, and it didn't seem
it was getting into the surface impoundment. And
we're going to do long-term monitoring of the surface
water and groundwater to make sure that there's
nothing going on. The net present worth is about
$673,000.
And then Site 7, there's no action

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alternative because Che site haa actually been cleaned
up under a pilot study. And that present worth is
obviously aero.
Just to move along to the public
participation. Our public comment period began today
in the newspaper in The Daily Press. Kaye talked
about that. And the purpose is to encourage you and
other members of the public to participate in that
process and the selection of the.proposed alternatives
for all four o£ these sites.
The comment period will close on
July 10th of 1998. It's a 4S-day comment period. We
looJc forward to hearing your comments today and by
mail or by phone call if you should choose to do that.
And on that, we'll go to comments,
questions, concerns, open the floor up to anything
anybody would.like to talk, about on these sites,
CINDY BARBRAO: Cindy Barbrau, York
County Business. You said chat Site 7 was done under
a pilot study. Do you have anything about
approximately how much that - -
SCOTT PARK: The COSt of it? ,
CINDY BARBRAU: Yeah.
JEFF HARLOWt It was a large-scale pilot
study.
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RICH HOFF; It was about a million
dollars.
SCOTT PARK: Did chat include Che
construction of Che cell?
RICH HOFF; Yeah. That included the
construction of the biocell area, the excavation of
the area which expanded in scope once we started into
the digging, which, I think, a lot of these areas will
probably grow past the data that we now have. The
nice thing about that is that although we did spend a
million dollars in the up-front, we are starting to
see some returns from the presence of the biocell, and
it's greatly cheapened the remedial action for Site
19 .
SCOTT PARK; The capital cost will be
recouped every time we use that cell, so it will be
recovered.
JEFF HARLOW: I guess the fortunate thing
or the unfortunate thing, however you look at it,
Grace came into play in the middle of all of this and
now we're looking,at another alternative, innovative
technology, to treat contaminated soils, along with
TCE.
The original plans of the cell was to,
you know, not only clean up S ite 7 and if, but we also
TAYLOB ASSOCIATES, INC.
-------
1
2
3
4
S
6
1
8
9
10
11
12
13
14
15
IS
17
18
19
20
21
22
23
24
25
COURT REPORTER'S CERTIFICATE
I, SCOTT D, GREGG, RPR, and Notary
public, certify that I recorded verbatim by Stenotype
the proceedings in the captioned cause before a public
hearing. Proposed Remedial Action Plans for*Sites
.l & 3 and Sites 6 & 7, Yorktown, Virginia, on May 26,
1993 .
knowledge and belief, the foregoing transcript
constitutes a true and correct transcript of the said
proceedings.
I further certify that to the best of my
Given under my hand this
day of
1998, at Norfolk, Virginia.
Scott D. Gregg
TAYLOE ASSOCIATES , INC .
-------
Rc: Naval Weapons Station
II 1*1 7:2
7|fi 7:19
22:7
filled 111 7:7
finding mi IK15
findings ru
first iiai
¦1:19
8:15
20:22
five mi
floor|i|
flume t«i
20:5
focus 11|
focused |s)
1.1:1! I4:ki
2:25
5-1
13:14
21:9
27:15
24:16
19:1?
21:15
11:25
7:3
7:22
13:24
13:23
J.21
6:10
19:21
20:3
13:111
15:9
23:3

excavation jji
17.2-1
20:4 20:7
21:1
25:6

except in 7 i?

excess 111 17:7

exist Ml >9:25

exists fii 17:5
1B:8
expanded mi
25:7
expecting |i|
22:25
expert mi 6:9

explosive m
10:23
11:7

explosives (ii
10:5
26:8 272

exposure m
14:23
19:22

cxtentist 15:16
15:23
17:1 17:10
17:15
1 -F-
lfacilitics|i|
6:16
facility r>i 518
5:19
8:21 8:23
9:11
11:8 11:24

fact(4| 13:14
13:2!
15:10 16:11

fairin 27:i i

Faf(}| 4:9
4:18
111:20

farming in
22:22
feasibility m
13:10
13:11 13:12
14:10
18:23

feet m 8 4
17:14
Fclgatcs ru
5:20
5:24 8:11
14:5
19:9

few |1J 12:4
14:6
15:6 .

Field (io| 5:21 ¦
5:25
7:10 8:2
8:4.
14:5 14:8
14.17
16:17 16.21

figure mi 15:16

figured Ml 15:19

figlUCSfll 14:12

18:1
focusing [11
follow (i) 4:21
foregoing m
forrai(t| 16:14
format mi <1:4
fonncr(i| i3i2l
fortunate mi
forwardtu
found (i) 21:19
fourrsi 4:19
5:10 17:14
OCMI 3:13
equency (i)
Sui 15r9
tit ill 22:20
future («t
16:5
23:12
9:17
19:22
-G-
G(H 2:1
general (ii 9:25
generally j«j
6:23 10:6
gentlemen m
given pi 12:23
glassware ni
goes PI 26:21
good (4) 4:23
125 17:14
goofed fl| 2:5
government pi
27:6
Grace hi 22:15
26:6 26:19
27.-9
grading [t 121:5
gravel (i| 20:25
graces ni 16:10
greatly in 25:13
greets w 7*
grccnbooseni
Gregg ril 28:2
grinding ni
6:19
ground (i | 7:21
groundwater hi
16:21 23:17
grow (It 25:9
growth [i i 8:10
guess fill 3:21
4:23 5:16
6:25 10:6
10:21 11:19
25:18 26:1
guys(l| 20:24
2!.2t
JK:9
25: IN
24:13
22:8
5:4
24:10
14:23
18:1
13:12
20:13
22:17
14:25
19:24
6:14
19:9
2:23
28:12
6:15
26:2)
8:1
22:16
25:20
27:7
22:23
28:18
6:13
14:7
23:22
4:14
6:9
10:7
19:25
h»'f IN 11:14
hand M| 2K:!2
handle it | 17-1 j
hardm i2:j
Harlow [T| i ift
6 7 fi K
2M» 37 14
health ni 14 19
19 22
hearing pi 24: U
28:5
helpui 2(1:25
27:11
hierarchy ri I
highm 15:11
highly m 19 23
hindsight mi
hitfll 412
Hoff [4| 1:17
25:1 25:5
hole |4| 7:2
7:21 23:3
hooked tn 92
hoping m 26:6
hotfi 15:3
15:22 16:7
17:25 18:9
hotlSC |1| 22:2
HRSDui 9:2
human (i| 1419
20:1U
-H-
J 21
24-Z<
16:5
27:19
27:7
13:1
15:12
27:12
26:2
12:14
7:)
15:21
17.1
22 3
11:15
19:22
-I-
idcam 17-.4
identified(ii i7:io
17:13
impoundment Mil 9 22
9:23 10:17 10:21
19:12 19:16 19 23
20:3 20:6 21:12
21:17 23:20
improvements mi K>:7
Incut 1:17 1:22
include (II 25:3
included (ii U:7
25:5
incorporate mi 3:22
incorporating in 8:14
15:21
increased mi 15: ia
Indian not 5.21 5 25
7.10 8:2 K.4
14:5 14:8 14:17
16:16 16:21
industrial iti 717
Industryiii 26.15
inert ii I 6:20
information i«i 3 14
12:23 13:3 13:19
innovative in 25:21
inside m 9:12 10: la
10:13
install in X 2J
instead hi H;2
excavation
intendiu jh i
interconnected ncss h i
14.7
larS'
interested hi
27:10
interesting | ii
inventor 11[
investigation m
14:5
investigations |3|
13:9 IK.22
18:25
involved hi
13:17
itCKISHI 27 4
itself|s| 7 io
9:15 10:17
11:11 21:7
Jayui
2:14
Jeff mm
2:24
3:21
6:8
21:1R
25:IB
jobdt
jobs (ii
27:8
joint (ii
26.-9
JulyiM
24:12
2:7
1:16
3:8
5:6
19:10
23:18
27;|4
12:7
26:19
4:15
2:20
Kayefiit
2:13
36
5:12
kccp(i|
kettle (i i
kind (7|
6:25
8:9
kitscn
knocking ii i
knowledge m
28:9
2:2
2.15
4 16
5:16
12:21
11:11
3.25
7:8
16:23
17:1J
3 21
17 1
2V2J
13 K
D'fi
! H.22
J 25
y 9
in 22
:fi,7
2 13
2.22
3 17
6.6
20:13
24 24
27:3
22:14
; N
2:2
3:3
5 6
24.6
4 HI
8:3
93
! 7 4
lab («| 26:2(1
26 22
26:24 27:4

landiit IK: 15
22.22
laad-usciM
2(1-1 1
landfill mm
6. Il»
6:19 7:4
7 III
7:14 7:24
K:K
8:10 13.22
15 24
17:4

landfills |i|
7:1
LANTm l:lK

latgCOl 10:22
15:1
IV. 11

Index Pi
-------
Rc: Naval Weapons Station
proposal mi
proposed (•>
2-IS 5:3
11:14 17.18
24:9 28:5
proposing (si
1722 19:5
22:21
prove [i i 28.7
provide (p
public mi 2:2
3:22 «:<
5:12 24:4
quality ui 14:13
questions pi
24:16 27:18
quick (ii 3:25
11:22
quicker [ii 13:3
quite pi 15:20
-R-
II) 25
11
12,20
19:5
17:16
22:11
27:3
2:21
4:13
24-5
28:3
24:8 27:19
28:4
purpOS«(U 24:7
put {Si 10:18 20:16
26:17
putting (it 7:24 8:25
-Q-
12:22
4:17
23:3
R[i| 2:1
RAA-4fi| 18:7
RAAs (il 17:21
RAB(2) 3:23 4:7
rap(t| 12:5
rather pi 13:11 13:13
14:23
ravine in 14:15
ready m 22:5
real (si 4,17 7:14
really p«( 10:22 13:18
14:1(7 14:21 15:1
15:7 15:19 16:1
17:2 17:4 18:2
16:5 18:14 22:1
reason pi 6:1
reasons pi 16:20 18:1
recap (i) 13:6
received III 12:25
receptors pi (4^2
14.15 15:5 * 16:4
16.6 20:3 20:111
reclaim (ti8:22
recommendations p i
13:2
rcconUuninatepi 23:15
recorded (il 28:3
rccoupcdpi ,25:16
recovered |i| 25:17
nxungularm 21:25
redril 17:11
reduced m 8#
rccstabliahni 1723
reestablished hi
rccsiablishmcnti
regarding pi
Jri2
Region pi i iv
14:4
Registered mi
rcg fading m
regulators Hi
reiicriicdi
remedial im
2:3 12:16
13* UK
17:16 17:17
18-16 18:22
195 21.23
25.13 28:5
remediation in
remedy pi 15:25
rcmcmbcrtu
remote (i i 11:24
rcrootelym
removal pi
12:6 17.24
23:6 .
remove pi 18:S
removed (ii
repeating pi
replaced pi
3:6
report pi 18:24
REPORTER'S («i
Reporters ni
represents (ii
5:19
required hi
research pi
resident (i i
residential (3i
19:25
residual (ii
returns p| 25:12
icvcgctatedpi
rcvicwrn (9:6
RIpl 13:8
Rich(i| 1:17
4:2 ( 10:21
12:14 25:1
Rich's (I ( 12:8
tight ii*i 3 4
7.1t 9:6
10:24 11:12
20:18 21:16
22:19 22:25
right-hand i ii
ripiM 12:5
! risk isi 12:19
16:15 16:17
risk-driven pi
risks p«| 14:20
1422 lyf,
1*6 19:21
2(1:2 20: III
2(1:12 21:19
15 2<
II 14.2
2:17
12.25
1,23
21 ft
13:18
11:16
1:7
12:10
14:9
17:19
18x25
22:9
2:18
16:3
16:8
(2:1
10:12
20:12
23.8
20:15
5:6
2:3
28:1
1:23
5:17
2:17
9:4
&:9
19:22
23:9
214
18:22
3.7
12:1}
25:5
5:22
111:23
12:2
21:20
26:11
6:24
14:10
19:20
16:1
14:21
16:5
2(4-1
211:11
22:8
road (-M 6.24
7 2* KK
roads in 7 23
Rob pi y.f>
rod p| 8:17
Rodham tit
Round lit .3:8
RPR HI 28:2
run IS| 2:21*
8:4 12:5
running pi
23:7
rmnspi 19:8
proposal
S(i| . 2:1
saberpi 20:(7
sacrificing (ii
samples pi
17:6
sampling (it
sand pi 7:2
save in 4:5
saving pi 6:4
saw pi 14:|4
scenario pi
6:25 20:11
scheduled m
schedulesfti
scope pi 25:7
Scott(i«i
4:21
18:18
25:3
26:11
28:2
screened tu
second pi 3:2
sediment(i|
1:18
11:12
18:20
25:15
26:14
28:18
see(M|
7:7
8:17
9:24
11:2
12:3
10:8
6:24
7:25
9:20
9:34
11:3
16:23
21:25
seeing (*i 2:4
8:5 8:8
11:4
seem pi 23:19
selected pi
22.9
selection nt
24:9
sense in 6*
18:14
SCOtpi 2:22
separately
8:19
service 111 27: IA
set |1| 4:1(1
seven in iw
shadow* |i|
share (i| 27:11
7:1 J
X.l"»
2(1.2(1
13:8
8:3
12:23
2.17
26:23
4:7
15:21)
15:16
16:9
3:22
4:9
9:17
3:7
13:5
24-J2
26:4
27:17
19:2
10:6
19:23
7:5
8.9
9:21
10:17
12:3.
19:7
25:12
7:10
10:23
18:7
19:4
18:3
4,4
27:15
9:21
sharc-costm
shorter mi 12 2J
show |I| 21 2
.showed in i
6.14
7.23
HI 2
14 11
M; i4
164
16:9
17:8
17:23
19:12
19:21
211:19
22: i»
23.25
25:13
26:4
IK
4 17
•5:5
?.Il
5-25
8:7
8;IS
13 4
13 15
15 21
22:111
28:5
18.3
19:
24 17
situ pi
22:11
situationpi
SI* |i| 5:1
size hi 18.10
slide pi ! 17
6.22
slides pi 4-19
slights 16 if
sludge Ml 23 6
SiudgCS|l|I6 to
slurry in 2» n-
smalli*i
17:1
18:13
soil 1*1
17:24
13:2
soils P|
solid pi
17 3
solution 111
solvents pi
7.5
17 11
17:12
19 21
14 11
13:22
solvents
18
19 12
•0:22
l«:3
15 7
26:13
»H7
22:12
6:8
6 21
8.12
10 5
14 II
14:18
16:8
16:24
17:11
18:7
19:13
20.9
20:21
23:11
24:1
23:25
1:8
5 I
5:5
5 21
6.5
t:!6
12:16
13:7
15:6
18.23
24.10
28-6
18.4
17.8
19 3
5:22
12:4
13:13
18.2
17-23
20:15
25:22
15:24
10:11
16:10
Index Pag
-------
Rc: Naval Weapons Station
S673,000r«i
23:24
"40s(i|
10:8

'80s pi
9:5
11:18
'S6jii
9:5

*97(11
5:2

-1-
1 (»|
1:8
2:18
5J
5:11
5:21
5:25
6:10
6:21
8:15
13,-4
13:7
13:8
13:21
14:||
14:13
15:10
16:24
17:7
17:23
18:21
20:6
21.#
21:20
23:1
23 8
23:18
28:6

10 til
2:20

109 w
9:20
10:17
11:17
19:16

lOthpi
5:14
24:12
12 |i|
19:14

13f«l
19:15

14 in
lt:i

15m
19:17

155,000 m
18:17
19m
20:19
25:14
25:25

19003(11
7:1#

1942in
10:19

1942-43
m
8:22
!965(i|
6:11

I975(i|
m*
11:12
11:14

1979 m
6:11

1998cn
1:12
5:14
24:12
28:7
28:13
-2-
2(41
13:8
20.7
Z1.9
21:16

26 rn
1:12
5:11
28:6

26(fa|i|
1:19

-3-
3 (Ml
1:8
1:19
2:19
5-3
5:11
S;2t
6:1
7:12
7:21
8:15
12:25
11:4
11:7
I4;4
14:11
14:14
14:1*
16:4
16:8
16:9
17:8
17:11
18:7
18:21
20:7
23:2
2K:6

-4-
45 ill
2:17
5:11
45-daypi 24.12

461-1984 |i|
1:24
-6~
6 mi
1:8
2:19
5:5
5:11
5-J I
iXS
8:12
H:IS
K.2I
11:6
11,17
13:5
18:19
(8:21
19:7
19:9
19:21
22: SO
22:10
26:1
26:4
28:6

63 pi
15:13
15:21
-7-
7 |J4|
1:8
2:19
5:5
5:11
5:21
5:25
8:18
11:6
11:7
11:17
13:5
18:19
18:21
19:7
19:12
19:14
20.-9
20:21
21:8
22:10
23:25
24; 19
25:25
28:6

757 hi
1:24

7:10(i|
27:19

-8-
I87-4939(u
3:12
-9-
95 th (u
15:2

able i»i
11:17

above pi
15:12
15:22
absorption (m
8:21
access hi
6:24

action fi«i 1:7
5:4
12:6
12:16
13:15
16.1
17:17
17:19
18:16
19:1
19:5
211:12
21:21
23-25
25:13
28J

actions p| 12:20
17:18
actual pi
9S
11:7
11:24
11:25
21:21
ad ni
2:16
3:13
additional pi
15:15
15 20
16:19

address |i| 16:2

adult (t|
16:1

affairs (ti 2:3

again (ii|
4:3
14:22
15:24
16:1
16:4
(6:15
16:18
16:23
17:8
18:10
18:13
1X:21
19:2
19:5
21:9
22:10
21:18
agenda (i| 3:19

agom
2:4
11:19
12:7

ahead (ii
2:12
4S
27:15

alleviated hi
allowed]!;
almost (ii 2;$
along (•! 2:24
9 2? 10:}
21:15 24:4
alternative hi
22:9 24-4
alternatives [«i
19:1 21:21
always m 8:22
amenable mi
amounts na
analytical in
27:5
annex in ki j
announced (it
Mincemeat t
Z tn 20:5
(6:21
arcafjTj
7:1
7:9
7:17
10:1
16:24
17:12
18:14
19:15
20:1
203
20:7
21:4
21:15
21:20
21:24
22:6
21:2
23: It
15:7
areas (*1 5:22
13:24 17:7
20:4 21.-9
Annym 6:16
arsenic pi 15:11
17:1 17:5
assessments
5:20
7:5
7:! 2
9:21
UttO
17:6
17:25
19:8
19:17
20:1
20:6
20:7
21:5
21:16
21:20
22:3
23:1
23:8
23:19
19:2(1
assessments m
ascctto 4:i8
associated (si
17:21 21:19
27:4
ASSOCIATES m
average hi
averaged hi
X 25
4 IS
7 7
19:9
25:22
1B:16
15:21
14:9
2*3
27:12
- IU:22
12:18
4.9
4:12
14:1 J
1:15
9:19
tfi.16
6 23
7.6
7:16
9:25
15:1
17:1!
18.-9
19:10
19:23
20:5
20:6
20:23
21:10
21:17
21:21
22:4
23:2
23.11
25:6
13:12
20:4
25:8
15:18
17:25
M 21
12:19
17:211
22:8
1:22
15:2
15:1
-B-
$673,000
Bakcroi t n
business
EUrbcausi
IK 24 23
2h 12
based !»1 12:24
I>»2»
basement mi
bceamcjn?-3
began mi 24:5
beginningm
begins {t i 5:13
belief HI 2H.9
best in 9:5
better m 26:2
between rat
14:7
beyond m 6: tl
big in 4 J8
biocetlin 12:7
15:12
biological ra
22:12
biosliuryin
biotrcatment ii i
bisected m
bit pi 9:21
19:18
Blacktif
block in
board (i i
Bob m
3:2
3:6
4:24
bodyrii
bomb (i I
bombs im us
borrow pi 7:1
22:4
bottom hi 6:22
12:4 if: 17
boundaries it i
bounds in 19.8
branches rn
14:16
break m
brings in
broke hi
budget11| 3.18
building iui
9:13
9.IK
10:11
11:5
12:2
I9:l(»
21:13
23:1»»
2:1
23:10
4:17
1:19
3:3
4:16
17:2
10:13
backdrops hi
background pi
8:fi
15 13
7:11
14:17
8:19
27:8
19:2
9:14
9:20
111:16
11:11
19:1(1
21:10
22:2
23:11
buildings r> i
builtin to: ih
bunkers |i |
business 111
24.19
24 IK
2 ft?
16:7
22:2
8:1
28:8
8:3
7-9
6 17
25:6
22:11
12:7
20:16
14:15
18:19
2:24
3:5
4.23
22:3
7:25
7:9
8:2
27:15
99
9 15
Hh.6
10:19
11:21
19:11
21:11
21:7
23:12
MIT
10:19
12:1
A:I7
Index Pug
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