United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R10-92/037
December 1991
ŁEPA Superfund
Record of Decision:
Bangor Ordnance Disposal
-------
., , "
,
NOTICE
The appendices listed in the index that are not found in this document have been removed at the request of
the issuing agency. They contain material which supplement. but adds no further applicable information to
the content of the document. All supplemental material is. however, contained in the administrative record
-------
't
.,
50272-1 01
REPORT DOCUMENTATION T 1. REPORT NO. I ~ 3. Reclplenr8 A_Ion No.
PAGE EPA/ROD/R10-92/037
4. TI1Ie and SubdUe 5. Report Date
SUPERFUND RECORD OF DECISION 12/10/91
Bangor Ordnance Disposal (USN Submarine Base), WA 6.
First Remedial Action - Final
7. Aulhor(a) 8. Performing Organization RepL No.
9. Performing Orgalnlza1lon Name and Addr- 10. ProjectITaslrlWork Unit No.
11. ContracI(C) or GranI(G) No.
(C)
(G)
1 ~ Sponsoring Organlzadon Name and Addrea8 13. Type of Report & Period Covered
U.S. Environmental Protection Agency 800/000
401 M Street, S.W.
Washington, D.C. 20460 14.
15. Supplem...1Dry Notes
PB93-964601
16. Abstract (Umlt: 200 worcl8)
The 12-acre Bangor Ordnance Disposal site is located in the northern portion of the
U.S. Naval Submarine Base Bangor (SUBASE) in Kitsap County, Washington. The Site A
portion of the site consists of a 6-acre burn area, debris areas, and a storm water
discharge area. Land use in the area supports limited residential and undeveloped
forest land. Site A is located near Hood Canal which borders the SUBASE to the west.
The community of vinland is located approximately 2,000 feet from Site A. Several
residents who reside in Vinland use a shallow aquifer as their drinking water supply.
Municipal water supplies near the site are obtained from the deeper sea level aquifer.
From 1962 to 1975, the Navy used the site to detonate and incinerate various ordnance
materials. The site originally consisted of burn mounds, facilities for persormel,
fire suppression vehicles and equipment, an incinerator for ammunition, and a blast
pit for TNT detonation. Sediments from an ordnance waste water disposal lagoon were
disposed of and burned at the site through 1972. Buildings at the site were
demolished and burned on site in 1977. Grading and redistribution of soil at the Site
A burn area continued through 1984. In 1983 the Navy diverted surface water
discharges from the Site A Burn Area to Hood Canal, to minimize contamination to the
(See Attached Page)
17. Docum...t Analysl8 a. DescrIptors
Record of Decision - Bangor Ordnance Disposal (USN Submarine Base), WA
First Remedial Action - Final
Contaminated Media: Soil, gw
Key Contaminants: organics (PCBs), metals (lead)
b. IdSldlierslOpen-Ended T erm8
c. COSA 11 FIeIdIGroup
18. Availability Stetem...t 19. Security CIa88 (This Report) 21. No. of Pages
None 48
20. Security CIa88 (This Page) n PrIce
1\Tn1"l'"
(See ANSJ.Z39.18) See Instructions on Rt1tferSe OP110l'aLFO~-.J272(4-77)
(Formerly NTJS.35)
-------
f ,
,
,
EPA/ROD/RI0-92/037
Bangor Ordnance Disposal (USN Submarine Base), WA
First Remedial Action - Final
Abstract (Continued)
near town. This was done as a result of investigations conducted by the Navy 1978. This
ROD addresses contaminated soil and ground water at Site A. Future RODs will address an
additional six operable units comprising 20 known or suspected hazardous waste sites at
SUBASE. The primary contaminants of concern affecting the soil and ground water are
organic, including PCBs, phthalates, explosive compounds TNT, DNT and RDX, and lead.
The selected remedial action for this site includes excavating approximately 7,000 cubic
yards of soil from the Burn Area, which exceed action levels for TNT, DNT, RDX, and soil
from Debris Area 2, which exceed action levels for lead; modifying soil as necessary by
mechanical or chemical means to ensure effectiveness of subsequent treatment; treating
soil by soil washing until clean-up levels are attained; treating leachate by
UV/oxidation until clean-up levels are attained; placing a I-foot soil cover over the
treated soil; excavating soil containing concentrations of lead above the action level
after treatment for organics and ordnance compounds and disposal at a permitted off-site
facility; conducting ground water monitoring and treatability studies to support final
design of the ground water restoration plan; installing approximately eight extraction
wells near the Burn Area, pending final design; treating extracted ground water using
UV/oxidationi installing an effluent polishing system, in the event that ground water
treatment is inadequate; discharging treated ground water onsite; and monitoring ground
water. The estimated present worth cost for this remedial action is $2,700,000. No O&M
cost was provided for this remedy.
PERFORMANCE STANDARDS OR GOALS: Chemical-specific soil clean-up goals are based on state
standards and include TNT 33 mg/kg, DNT 1.5 mg/kg, RDX 9.1 mg/kg, lead 250 mg/kg,
phthalates 140 mg/kg, and PCBs 4.3 mg/kg. Chemical-specific ground water clean-up goals
are based on state standards and include TNT 2.9 ug/l, DNT 0.1 ug/l, RDX 0.8 ug/l, lead
-------
II ' 'J.I
,
,
.j" ". -_J I
DEClARATION OF
THE RECORD OF DECISION
SITE NAME AND LOCATION
Naval Submarine Base, Bangor Site A (Operable Unit 1)
Bangor, Washington.
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial action for Site A (Operable Unit 1)
at the Naval Submarine Base (SUBASE), Bangor in Bangor, Washington, chosen in
accordance with the Comprehensive Environrilental Response, Compensation, and Liability
Act, as amended by the Superfund Amendments and Reauthorizatiori Act, and to the
extent practicable, the National Oil and Hazardous Substances Pollution Contingency Plan.
This decision is based on the administrative record for the site.
The lead agency for this decision is the U.S. Navy. The U.S. Environmental Protection
Agency (EP A) approves of this decision and, along with the State of Washington
Department of Ecology (Ecology), has participated in the scoping of the site investigations
and in the evaluation of remedial action alternatives. The State of Washington concurs
with the selected remedy.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from this site, if not addressed by
implementing the response action selected in this Record of Decision (ROD), may present
an imminent and substantial endangerment to public health, welfare, or the environment.
DESCRIPTION OF SELECfED REMEDY
The selected remedy is the only response action planned for Site A This action addresses
contaminated soil and contaminated groundwater. The selected remedy will consist of the
following actions:
-------
,
,
j: j. I
Soil Remediation:
. Excavate approximately 7,000 cubic yards of surface soil from the Burn Area of Site A
containing ordnance concentrations above state cleanup levels for potential direct soil
contact exposures.
. Excavate approximately 100 cubic yards of surface soil from Debris Area 2 of Site A
containing ordnance and/or lead concentrations above state cleanup levels for potential
direct soil contact exposures.
. Place all excavated soils within a lined soil washing basin constructed within the Burn
Area. Debris Area 2 soils with elevated lead concentrations will be isolated in a special
cell within the washing basin. The excavated soils will be modified as necessary by
mechanical or chemical means to ensure that the subsequent treatment (washing)
process will be effective and efficient. .
. Dissolve ordnance contaminants from the excavated soils using a Soil Washing system,
and treat the leachate with Ultraviolet (UV)/Oxidation technologies to permanently
destroy the ordnance contaminants. Treated leachate will be recirculated to the
treatment basin, establishing a closed treatment system (i.e., no discharge).
. Monitor the effectiveness of the soil washing and treatment processes. Soil washing will
continue until state ordnance cleanup levels for potential direct soil contact exposures
are achieved, and leachate concentrations are below state groundwater protection
(drinking water use) levels.
. After soil (ordnance) treatment, remove soils originally excavated from Debris Area 2
containing lead concentrations above state cleanup levels for potential direct soil
contact exposures. These soils (approximately 100 cubic yards) will be disposed at a
permitted off-site landfill. All other soils will remain on site.
. Following completion of the soil treatment action, groundwater protection will be
assessed by monitoring ordnance concentrations in the seasonal Perched Groundwater
Zone immediately underlying the Burn Area. The point of compliance for comparison
with state groundwater protection (drinking water use) levels will be established
throughout the Perched Zone. If compliance with state groundwater protection criteria
has not been achieved within five years from commencement of this action,
modifications to the groundwater remediation system will be considered, as discussed
below.
-------
H"', .f
.
,
, I
Groundwater Remediation:
. Using approximately eight extraction wells, remove groundwater within the Shallow
Aquifer (below the Perched Zone) containing ordnance concentrations above state
groundwater cleanup levels (drinking water use).
. Treat the extracted groundwater using a UV/Oxidation process to permanently destroy
the ordnance contaminants and achieve state groundwater discharge standards prior to
disposal.
. Dispose of the treated groundwater on base (at the Bum Area) by reintroduction into
the Shallow Aquifer.
. Monitor the effectiveness of the groundwater extraction and treatment processes
throughout the restoration action, which may extend for a period of up to 10 years.
The system's performance will be carefully monitored on a regular basis and adjusted as
warranted by the performance data collected during operation.
DECLARATION
The selected remedy is protective of human health and the environment, complies with
Federal and State requirements that are legally applicable or relevant and appropriate to
the remedial action, and is cost-effective. This remedy utilizes permanent solutions and
alternative treatment or resource recovery technologies, to the maximum extent practicable,
and satisfies the statutory preference for remedies that employ treatment that reduces
toxicity, mobility, or volume as a principal element. Because this remedy may result in
hazardous substances remaining on-site above health-based levels after a period of five
years, a periodic review will be conducted in accordance with the existing Federal Facility
Agreement for SUBASE, Bangor to ensure that the remedy continues to provide adequate
protection of human health and the environment.
~~
SUBASE, Bangor Commanding Officer
United States Navy
0~1f9/.
Date
-------
(
.
.' - ,
. "
Signature sheet for the foregoing SUBASE, Bangor - Site A, Remedial Action, Record of
Decision between the United States Navy and the United States Environmental Protection
Agency, with concurrence by the Washington State Department of Ecology.
J)CUw.0-~
Dana Rasmussen
Regional Administrator, Region 10
United States Environmental Protection Agency
i:zl/j/Q /
f /
Date
-------
., ' '-. I
.
,
Signature sheet for the foregoing SUBASE, Bangor - Site A, Remedial Action, Record of
Decision between the United States Navy and the United States Environmental Protection
Agency, with concurrence by the Washington State Department of Ecology.
~- I.J-~
/.:J..! /0/ 9 I
Date
Carol Fleskes, Program Manager
Taxies Cean-up Program
Washington State Department of Ecology'
-------
.. J
1\ . \ I'
CONTENTS
Page
DECLARATION OF THE RECORD OF DECISION
1
DECISION SUMMARY
1
1.0 INTRODUCTION
1
2.0 SITE NAME, LOCATION, AND DESCRIPTION
1
3.0 SITE IDSTORY AND ENFORCEMENT ACTIONS
2
4.0 IDGHLIGHTS OF COMl\ruNITY PARTICIPATION
3
5.0 SCOPE AND ROLE OF OPERABLE UNITS
4
6.0 SUMMARY OF SITE CHARACTERISTICS
5
6.1 Soil Contaminants
6.2 Surface Water, Sediment, and TISsue Contaminants
6.3 Hydrogeology and Groundwater Contaminants
5
7
8
7.0 SUMMARY OF SITE RISKS
10
8.0 CLEANUP STANDARDS
13
9.0 DESCRIPTION AND COMPARISON OF ALTERNATIVES
16
9.1 Soil RemedWtion Alternatives
9.2 Groundwater Remediation Alternatives
16
18
10.0 COMPARATIVE ANALYSIS OF ALTERNATIVES
22
10.1 EvaIlUltion 01 Soil RemedWtion Alternatives by Criteria
10.2 EvaIlUltion of Groundwater Remediation Alternatives by Criteria
22
24
-------
,I , \,'
.
,
CONTENTS (Continued)
11.0 THE SELECfED REMEDY
11.1 Groundwater RemedUd Action Contingency Measures and Goals
11.2 Effectiveness of Treatment Technology
12.0 STATUTORY DETERMINATION
12.1 Protection of Human Health and the Environment
12.2 Complimu:e with Applicable or Relevant and AppropriDle
Requirements
12.3 Cost-Effectiveness
12.4 Utilization of Permanent Solutions and Altel7UJtive Treatment
Technologies or Resource Recovery Technologies to the Maximum
Extent Practicable
12.5 Preference for Treatment as Principal Element
TABLES
1
2
3
4
Summary of Chemicals of Concern
Selection of Exposure Pathways for Quantitative Exposure Assessment
Summary of Site A Exposure Factors
Summary of Site A Bum Area Baseline Risk Assessment;
Reasonable Maximum Exposure Scenario
Summary of Baseline Cancer Risk Estimates at Site A
5
Page
27
30
31
31
32
32
34
34
35
36
37
38
40
12
-------
'I \\;' , l.
CONTENTS (Continued)
~
FIGURES
1
2
3
4
Generalized Regional Map
Site A Vicinity Map
Site A Historical Features
Surficial Soil TNT Concentration Contour Map
Site A Burn Area
Conceptualized Flow Model of Perched Groundwater Zone
RDX Concentration Contours within the Shallow Aquifer
Baseline Exposure Pathways - Hypothetical Conditions
Site A Wen Layout
5
6
7
8
ATI'ACBMENT A
RESPONSIVENESS SUMMARY
A-I
OVERVIEW
A-I
SUMMARY OF PUBUC COMMENTS
A-I
RESPONSE TO COMMENTS
A-2
1. Effectiveness 01 RemedUd Adion Components A-3
2. Groundwater Sampling 01 Ojf-Base Residential Wells A-4
3. Effect 01 Pumping Residential Wells on the Movement 01 Groundwater Contllmination A-5
4. Sampling 01 Sediments and SheUfish A-6
5. Long-term Health Studies 01 Ym/and Residents A-6
6. Schedule 01 the RemedUd Adion A-7
ATI'ACBMENT B
ADMINISTRATIVE RECORD INDEX
B-l
-------
.1 , \.,'
.
I
DECISION SUMMARY
1.0 INTRODUCTION
Under the Defense Environmental Restoration Program, it is the U.S. Navy's policy to
address contamination at Navy installations in a manner consistent with the requirements
of the Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA), as amended by the Superfund Amendments and Reauthorization Act (SARA).
In the case of Ordnance Disposal Site A at U.S. Naval Submarine Base (SUBASE),
Bangor, remedial action will be implemented to minimize potential health risks associated
with soil and groundwater contamination. The remedial action will also comply with
applicable or relevant and appropriate requirements (ARARs) promulgated by the State of
Washington and the U.S. Environmental Protection Agency (EPA).
2.0 SITE NAME, LOCATION, AND DESCRIPTION
SUBASE, Bangor is located in Kitsap County, Washington, on Hood Canal approximately
10 miles north of Bremerton. The Bangor Ordnance Disposal Site A is located in the
northern portion of SUBASE, Bangor, approximately 2,000 feet southeast of Hood Canal
(Figure 1 at end of text). Land surrounding SUBASE, Bangor is generally undeveloped or
supports limited residential use. The residential community of Vinland is located
approximately 2,000 feet north of Site A The base and site are currently fenced, and
access to the site is limited to authorized personnel only.
Site A is composed of four separate upland areas totaling approximately 12 acres. The
size of individual areas ranges from less than one acre to approximately 6 acres, and all are
presently surrounded by forest. Ground elevation in the site vicinity generally ranges from
150 to 180 feet above mean sea level.
Surface water runoff from the site is directed northerly (towards Vinland) and westerly
(toward Cattail Lake), with eventual discharge into Hood Canal (Figure 2). Several
residences in Vinland obtain water supply from a (Qass II per EP A classification) Shallow
Aquifer, located approximately 60 to 100 feet below ground surface. However, municipal
water supplies in Vinland are obtained from the deeper, regionally extensive Sea Level
Aquifer, which is separated from the Shallow Aquifer by approximately 140 feet of low
permeability soils. .
Site A is composed of a Burn Area, two Debris Areas, and a Stormwater Discharge Area
(Figure 2). The Burn Area, which at 6 acres is the largest individual area of the site, was
used to detonate and incinerate various ordnance materials, including trinitrotoluene
(TNT), flares, fuses, primers, smoke pots, smokeless powder, and black powder. Inert solid
waste material (e.g., metal casings) resulting from the Burn Area operations was deposited
-------
.
I
.' ,
. \..
at the two adjacent Debris Areas. The Stormwater Discharge Area has received surface
water runoff from the Burn Area since a diversion structure was completed in 1983. As a
result of these activities, soil, surface water, and groundwater within various areas of Site A
have received different types and quantities of releases of ordnance compounds, their
breakdown products, and metals.
3.0 SITE mSTORY AND ENFORCEMENT ACTIONS
The Burn Area of Site A was used to detonate and incinerate various ordnance materials
beginning in 1962 and continuing to 1975. The site originally consisted of 24 burn mounds
and support facilities for personnel, fire equipment, and trucks. An incinerator for small
arms ammunition and dangerous pyrotechnic items was added between 1965 and 1970,
along with a shielded blast pit used for detonation of TNT. Figure 3 shows the historical
features at the site.
Demilitarization wastewater lagoon sediments containing ordnance residuals were
periodically excavated from Site F (Operable Unit 2 at SUBASE, Bangor) and transported
to Site A for burning and disposal. Site F sediments were received at the site through
February 1972, when 20 cubic yards of soils were excavated from the top several feet of the
former Site F lagoon area and delivered to Site A for burning.
Most detonation and incineration activities at Site A ceased by 1975. Operations buildings
were demolished and burned at the site in 1977. However, grading and redistnbution of
soils at the Burn Area continued through 1984. Limited testing of various ordnance
materials was conducted two or three times a year until 1986, when all such activities
ceased at Site A
In 1978, the Navy began an Assessment and Control of Installation Pollutants (ACIP)
program to evaluate waste disposal sites at SUBASE, Bangor, including Site A The
investigation was summarized in 1981 as part of an Initial Assessment Study (IAS). Based
on the results of the ACIPIIAS investigations, in 1983 the Navy diverted surface water
discharges from the Burn Area to minimize contaminant releases to Vinland. Since that
time, runoff has been diverted to the Stormwater Discharge Area, with eventual discharge
into Hood Canal (Figure 2).
Investigations at Site A continued in 1986 as part of a Characterization Study under the
Navy Assessment and Control of Installation Pollutants (NACIP) program. In that year,
Congress enacted the Superfund Amendments and Reauthorization Act (SARA) which
required federal facilities to comply with the EP A's procedures at inactive waste sites.
On July 22, 1987, the EPA listed Bangor Ordnance Disposal Site A on the National
Priorities List (NPL) of Hazardous Waste Sites. As a result, the Navy suspended further
-------
, '.-
.' .
, .
NACIP program activities and phased into the EP A Remedial Investigation/Feasibility
Study (RIIFS) program.
4.0 IDGHLIGHTS OF COMMUNI'IY PARTICIPATION
The Community Relations Plan for Site A is presented in the Management Plan for the
site, available for review in the information repositories. Community relations activities
have established communication between the citizens living near the site, the Navy, and
EP A Discussion between the different groups for information purposes and suggestions
on the project has been open. The actions taken to satisfy the requirements of the federal
law have also provided a forum for citizen involvement and input to the remedial action
decision.
The community relations activities at the site included the following:
~ Technical Review Committee (TRC) meetings with representatives from surrounding
communities;
~ Issuance of three fact sheets for the Site A RIIFS, which provided updates on the work
being performed and major findings; and
~ Coordination with other citizens groups formed in response to site investigations of
concern to the community.
The specific requirements for public participation pursuant to CERClA Sections
113(k)(2)(b) and 117(a) include releasing the Proposed Plan to the public. This was done
in August 1991. The Proposed Plan was placed in the administrative record and
information repositories. Attachment B presents the Administrative Record Index.
The information repositories are located at Kitsap regional hbraries:
Bangor Branch (206) 779-9724
Naval Submarine Base, Bangor
Silverdale, Washington 98315-5000
Main Branch (206) 377-7601
1301 Sylvan Way
Bremerton, Washington 98310
-------
,
\
.. ~~ , I..
F
The Administrative Record is on file at:
Engineering Field Activity, Northwest
Naval Facilities Engineering Command
3505 N.W. Anderson Hill Road
Silverdale, Washington 98383-9130
(206) 476-5775
Notice of the availability of the proposed plan, plus notice of a public meeting on the
proposed plan and public comment period was published in the Silverdale Reporter
(August 14, 1991), Bremerton Sun (August 14, 1991), North Kitsap Herald (August 14,
1991), and Trident Times (August 16, 1991). A public comment period was held from
August 14, 1991 to September 12, 1991. A public meeting was held on August 21, 1991,
with presentations given by the Navy, EP A, and the Washington State Department of
Ecology (Ecology). A total of 37 people attended the public meeting.
Eight comments (total) were received by the Navy concerning the Proposed Plan. All
comments were submitted and discussed at the public meeting. The public comments are
summarized and responses presented in the Responsiveness Summary (Attachment A)
portion of this document.
5.0 SCOPE AND ROLE OF OPERABLE UNITS
Two NPL sites occur at SUBASE, Bangor. The first is Bangor Ordnance Disposal Site A
(Operable Unit 1), which was listed on the NPL on July 22, 1987. This Record of Decision
addresses all of Operable Unit 1. On August 30, 1990, the remainder of SUBASE, Bangor
was listed on the NPL, including an additional six operable units comprising 20 known or
suspected hazardous waste sites. Site A is geographically separate from the other operable
units that comprise the second Bangor NPL Site.
The selected Remedial Action at Site A is a measure to minimize potential future health
risks associated with soil and groundwater contamination at the site. This action includes
soil treatment to address risks posed by direct contact exposures at the site. Soil treatment
will also address further releases of contaminants to surface water and groundwater. The
selected groundwater action includes extraction of contaminated groundwater present in
the Shallow Aquifer underlying Site A, treatment of the extracted waters to required
cleanup levels, and reintroduction of the treated waters back into the aquifer system. The
groundwater restoration action addresses principal and low-level risks posed by potential
future water supply use of site groundwaters.
-------
I ''-
.' '
.
.
6.0 SUMMARY OF SITE CHARACfERISTICS
This section presents a summary of site conditions including the nature and extent of
chemical contaminants. Migration pathways and transport characteristics of site
contaminants are also discussed. A summary of baseline site risks is presented in the
following Section 7.0.
The site characterization summarized in this section was based on the combined results of
sampling performed over the period 1978 to 1990, as summarized in the RIJFS report.
However, only the more recent 1987 to 1990 validated data were - used in the assessment of
site risks (summarized in Section 7.0).
6.1 Soil ContamilUlnts
Soil quality data were collected at Site A during two principal sampling periods. The first
occurred over the period 1978 to 1982, and was conducted by SUBASE, Bangor under the
ACIP program. The second sampling was conducted by Hart Crowser in 1988 as part of
the RIIFS. The constituents analyzed during the earlier Navy soil samplings were largely
limited to TNT and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), which were the primary
("parent") components of the ordnance materials handled at the site. The more recent
Hart Crowser samplings included the determination of priority pollutant metals,
semivolatile organics, pesticides, and polychlorinated biphenyls (PCBs), along with a wider
range of ordnance compounds and their degradation products.
Consistent with the prior detonation and incineration activities, data collected during the
RIIFS revealed the presence of ordnance compounds and associated chemicals including
TNT, RDX, 2,4- and 2,6-dinitrotoluene (DNT), 1,3,5-trinitrobenzene, 1,3-dinitrobenzene,
nitrobenzene, picric acid, picramic acid, Qtto fuel, and tetryl. Administration of these
ordnance compounds in animal bioassays has been shown to result in effects to the liver,
prostate, and spleen. Animal studies also indicate that DNT is a probable human
carcinogen. Based on limited animal data, TNT and RDX are considered possible human
carcinogens.
The maximum total ordnance concentration in soil (primarily represented by TNT) was
approximately 0.2 percent by dry weight (2,000 milligrams per kilogram; mg/kg), detected
in a sample collected from a former bum mound. The ordnance concentrations
encountered are not considered an explosive or fire hazard. Soils at Site A also do not
exceed designation criteria for characteristic dangerous or hazardous wastes, and are not
listed hazardous wastes.
The distribution of TNT in surface soils at the Bum Area is depicted on Figure 4. The
highest concentrations of ordnance at Site A (e.g., TNT at 1,300 mg/kg) have been
detected on some of the former bum mounds and in the vicinity of the former Bum Area
-------
.
.
ft.. \- \ (.
blast pits (Table 1). Similar concentrations and spatial distnbutions of TNT and RDX
were observed between the earlier (1978 to 1982) and most recent (1988) samplings.
The concentrations of ordnance in Bum Area soils are largely confined to depths within 1
to 3 feet of ground surface. The concentrations of most ordnance compounds, particularly
TNT, decline approximately 100-fold over the top 3 feet of soil. TNT has not been
detected (at the 0.1 mglkg detection limit) in soils collected below a depth of 3 feet. TNT
has also not been detected in site groundwaters (see Section 6.3). Approximately 7,000
cubic yards of soil at the Bum Area contain TNT concentrations above 30 mglkg, the risk-
based soil cleanup level (see Section 8.0).
RDX was detected along with TNT in surface soil samples collected from the Bum Area.
However, unlike TNT, low-level concentrations of RDX have migrated further through the
underlying soil. RDX has been detected in Shallow Aquifer water samples collected
approximately 70 to 80 feet below ground surface (see Section 6.3 below). Soil
concentrations of RDX below a depth of 30 feet were less than the 0.1 mglkg detection
limit. Compared with TNT and the other ordnance compounds detected at Site A, RDX is
relatively soluble in water and is readily transported with groundwater flows. Sorption of
RDX onto soils results in only minimal retardation of the movement of this chemical.
Subsurface transport of RDX is discussed in more detail in Section 6.3.
Other (non-ordnance) chemicals detected in soils of the Burn Area included metals
(chromium, copper, lead, nickel, and zinc), di-n-butylphthalate, and PCBs. The detected
levels of these chemicals were typically lower than soil ordnance concentrations, and were
also below soil cleanup levels established under the Washington State Model Toxies
Control Act (MTCA; Chapter 173-340 WAC; see Section 8.0 below). Maximum
concentrations of lead, di-n-butylphthalate, and PCBs were approximately 80 mglkg, 3
mg/kg, and 0.1 mg/kg, respectively (Table 1). Detection limits for these chemicals were 10
mglkg, 1 mg/kg, and 0.1 mg/kg, respectively.
Similar to conditions in the Bum Area, surface soils from the upper regions of Debris Area
2 contained detectable concentrations of ordnance compounds (particularly TNT, with a
maximum concentration of 72 mg/kg; Table 1). However, soils collected from Debris Area
2 exhIbited higher concentrations of metals (barium, cadmium, chromium, copper, lead,
and zinc) and several organic compounds including bis(2-ethylhexyl]phthalate, di-n-
butylphthalate, and PCBs. The most prevalent metal was lead, which was detected in
surface soils of Debris Area 2 at a maximum concentration of 2,400 mg/kg. Lead exposure
has been associated with blood and neurobehavioral effects in children and is also a
probable human carcinogen. The maximum total phthalate and PCB concentrations
detected at Debris Area 2 were approximately 1 mg/kg and 4 mg/kg, respectively. Bis(2-
ethylhexyl)phthalate and PCBs are considered probable human carcinogens.
-------
, ,~
.' '
.
,
Because of its small size, a relatively limited quantity of contaminated soils is present at
Debris Area 2. An estimated 100 cubic yards of soil in this area contains chemical
concentrations (primarily TNT and lead) which exceed MTCA soil cleanup levels. This
estimated volume is less than two percent of the similarly contaminated soil volume in the
Bum Area.
Little contamination of soils in Debris Area 1 and in the Stormwater Discharge Area has
occurred. No ordnance compounds were detected in soil samples collected from these
areas. A summary of soil contaminant concentrations at Site A is presented in Table 1.
6.2 Surface Water, Sediment, and Tissue Contaminants
During periods of relatively intense rainfall, stormwater runoff is discharged from the Site
A Burri Area up to a maximum measured flow of approximately 1 cubic foot per second.
Water samples collected during these ephemeral peak flow periods contained the highest
number and concentrations of ordnance compounds relative to all other surface waters
sampled at Site A During the 1987 to 1989 RIlFS sampling period, the chemicals detected
in Burn Area stormwater included TNT (to 140 micrograms per liter; ILg!L), RDX (to 39
ILg!L), DNT (to 0.3 ILg!L), and several other ordnance chemicals present at the limits of
detection (roughly 0.1 ILg/L). Lead, di-n-butylphthalate, and PCBs were not detected in
runoff from the Bum Area.
Surface runoff from the Bum Area was diverted in 1983 from Vinland Creek to the
Stormwater Discharge Area where runoff infiltrates into a shallow interflow zone through
permeable surface soils. This water emerges as seeps from the base of the Stormwater
Discharge Area near the beaches of Hood Canal (Figure 2). Seepage waters contained
RDX at an average concentration of 5 ILg/L (maximum 17 ILg!L). Average concentrations
of TNT and DNT were substantially lower at 0.4 ILg!L and less than 0.1 ILg/L, respectively.
Soil sorption within the Stormwater Discharge Area appears to reduce the concentrations
of TNT and DNT during interflow transport. Because of its greater mobility, RDX is
attenuated to a lesser extent during subsurface transport. No ordnance compounds were
detected in sediment or shellfish tissue samples collected from the Hood Canal beach areas
near the seepage discharge.
Surface water in Vinland Creek near the SUBASE boundary continues to exhibit low
concentrations of ordnance compounds, though current concentrations are approximately
200 times lower than those measured prior to the 1983 diversion. Average concentrations
of RDX, TNT, and DNT detected during the RIIFS sampling of these surface waters were
3 ILg!L, 0.2 ILg!L, and 0.1 ILg/L, respectively. Low concentrations of DNT (to 0.02 mglkg)
were also detected in Vinland Creek sediment samples. No ordnance compounds were
detected in sediment or shellfish tissue samples collected from the Hood Canal beach areas
near the Vinland Creek discharge.
-------
.
,
.. L' 't.
Cattail Lake contained low but detectable concentrations of RDX, TNT, and DNT at
average concentrations of approximately 0.6 ~g/L, 0.09 ~g!L, and 0.03 ~g!L, respectively.
No ordnance compounds were detected in sediment or fish tissue samples collected from
Cattail Lake.
6.3 Hydrogeology and Groundwater Contaminants
Groundwaters occur at Site A in two zones, as depicted on Figure 5. The first - the
Perched Groundwater Zone - is a seasonal unit present at a depth of 10 to 15 feet below
ground surface in the Burn Area. The Perched Groundwater Zone occurs within
recessional outwash deposits of gravelly, silty sand. Concentrations of ordnance have
historically been highest in waters collected from the Perched Groundwater Zone.
Some of the older monitoring wells completed in the Site A Perched Groundwater Zone
appear to lack proper surface seals to prevent direct discharge of surface water into the
well. For those site contaminants such as TNT which appear to be largely confined to
surface media (i.e., surface soils and associated runoff), down-hole contamination of
groundwater samples obtained from these older wells is possible. For this reason, the
characterization of overall chemical quality in the Perched Zone was based primarily on
samples collected from newer wells with competent seals.
The only ordnance compound detected in newer wells completed in the Perched
Groundwater Zone is RDX. Concentrations of RDX in this zone over the 1987 to 1990
RIIFS sampling period averaged approximately 19 ~g!L (range: <0.1 ~g!L to 61 ~g!L;
Table 1). RDX concentrations in the Perched Groundwater Zone were also similar to
those detected in surface water runoff (average = 20 ~g!L; range: < 1 to 39 ~g!L). In
contrast, surface water TNT concentrations (to 140 ~g!L) are far greater than those of the
Perched Groundwater Zone «0.6 ~g!L). In this case, even relatively small movements of
surface water into the older wells would be expected to have a substantial effect on TNT
concentrations within the wells. Conversely, RDX concentrations within these older wells
may be relatively unaltered by such an occurrence.
If all of the RDX data collected from both newer and older wells are assumed to be
representative of conditions in the Perched Groundwater Zone, a highly significant
downward trend in concentrations over time is apparent. RDX concentrations in the
Perched Groundwater Zone have declined from approximately 1,000 to 10,000 ~g/L during
the early 1980s to the recent (1987 to 1990) range of less than 0.1 ~g!L to 61 ~g!L The
average rate of decline of the historical concentrations is approximately 30 percent per
year. For reasons discussed above, it is unlikely that the apparent lack of surface seals on
many of the older wells substantially influenced the observed decline of RDX
concentra tions.
-------
.1' I..""
.
,
The observed rate of decline in RDX concentrations is also consistent with the model of
contaminant transport through this zone. Primarily as a result of rainfall infiltration,
groundwater is rapidly flushed through the Perched Groundwater Zone, with discharge
both to local surface waters (Vinland Creek) and the underlying Shallow Aquifer (Figure
5). On average, groundwater is flushed through the Perched Groundwater Zone in less
than one year. Because of its mobility, RDX transport is not substantially attenuated by
soil sorption processes. .
The Shallow Aquifer is located approximately 60 to 100 feet below ground surface, and is
separated from the Perched Groundwater Zone by Vashon Till, as depicted on Figure 5.
The till consists of a dense, gravelly, silty sand which is approximately 15 feet thick beneath
the Burn Area. The till forms a low permeability veneer over the site which limits the rate
of infiltration to the underlying Shallow Aquifer. Nevertheless, some of the groundwater
from the Perched Groundwater Zone leaks through the Vashon Till and into the
underlying Shallow Aquifer. The remainder of the Perched Groundwater Zone flow is
discharged to Vinland Creek. .
Unlike the Perched Groundwater Zone, groundwater flows relatively slowly through the
Shallow Aquifer, requiring approximately 15 to 50 years to travel 500 feet across the Burn
Area. The Shallow Aquifer is used for water supply by several residences in the adjacent
community of Vinland, 2,000 feet north of the Bum Area. However, the flow direction of
the Shallow Aquifer beneath the Burn Area is west to northwest toward Cattail Lake (i.e.,
not toward Vinland; Figure 6).
RDX was the only ordnance compound detected in the Shallow Aquifer. The highest
concentrations were observed below the center of the Burn Area, where levels up to
189 ",gIL were detected during the RIIFS sampling (Figure 6). During the 1987 to 1990
sampling period, measured concentrations of RDX at this location were also higher than
those observed in the overlying Perched Groundwater Zone. However, during previous
(historical) samplings dating back to 1980, this pattern was reversed, with higher RDX
concentrations (1,000 to 10,000 ",gIL) previously detected in the Perched Groundwater
Zone.
The existing distnbution of RDX within groundwaters at Site A is consistent with leaching
of this chemical from prior ordnance detonation and disposal activities (RDX is relatively
soluble in water), foIIowed by rapid transport through the Perched Ground~ter Zone with
slower migration of the leaked material through the underlying ShaIIow Aquifer. As RDX
concentrations in the Perched Groundwater Zone have declined, past RDX releases have
accumulated within the relatively poorly flushed ShaIIow Aquifer.
Detectable concentrations of RDX are largely confined within the boundary of the Bum
Area, within an estimated groundwater volume of less than 300,000 gallons (Figure 6).
RDX has occasionally been detected in areas north of the Bum Area, though these
-------
.
\
IL \' ".
detections have all been at concentrations near the analytical detection limit. Additional.
sampling of the Shallow Aquifer is ongoing (using an improved low-level analytical method)
to more precisely define the boundary of RDX contamination in this area. No ordnance
compounds have been detected in off-site wells at Vinland screened in the Shallow
Aquifer.
The Sea Level Aquifer is located below the Shallow Aquifer. The Sea Level Aquifer is
separated from the Shallow Aquifer by approximately 140 feet of low permeable soils,
providing an effective barrier to downward migration of water. This deeper aquifer is
regionally extensive and is used for municipal water supply within the community of
Vinland. Ordnance compounds have not been detected in any of the local Sea Level
Aquifer wells.
Lead and bis(2-ethylhexyl)phthalate were occasionally and sporadically detected in surface
waters and groundwaters throughout Site A at concentrations exceeding published water
supply action levels of 15 p.g/L and 4 p.g/L, respectively (Table 1). However, similar
concentrations of these chemicals were observed at locations beyond the influence of Site
A, and may represent an area background condition. The detection of these chemicals in
water was also not correlated with detections in soil media. For these reasons, lead and
bis(2-ethylhexyl)phthalate were not considered contaminants of concern in water at Site A
Similarly, PCBs were not detected in water samples collected from Site A
7.0 SUMMARY OF SITE RISKS
All chemicals detected at Site A were screened following EP A's 1989 Risk Assessment
Guidance for Superfund to identify those chemicals which in the aggregate contnl>ute 99
percent or more of the cumulative site risk. Selection of such indicator chemicals was
based on consideration of the concentrations encountered, environmental mobility, and
toxicity. Chemicals eliminated in the screening process included several metals (e.g.,
arsenic), herbicides (e.g., 2,4-D), and some ordnance degradation products (e.g., 2,6-
diamincr4-nitrotoluene). The eliminated chemicals were either present at concentrations
typical of natural background conditions or were below conservative risk-based criteria.
Some of the eliminated chemicals lacked quantitative toxicity information necessary to
assess human health or environmental risks. .
The ,screening procedure identified 25 constituents which may be of concern at Site A
These indicator chemicals include: eight metals and inorganics (pH, barium, cadmium,
chromium, copper, lead, nickel, and zinc); eleven ordnance chemicals (predominantly TNT,
DNT, RDX, and associated compounds or by-products), four phthalate esters (e.g., bis[2-
ethylhexyl]phthalate); and two PCBs (Aroclor 1254 and 1260).
A quantitative human health risk assessment and semi-quantitative ecological evaluation
was performed for Site A to assess baseline risks at the site under a no-future-action
-------
.,, 'I ~
.
I
scenario. Only those exposure pathways likely to be important to the overall human health
risk assessment were retained for quantitative evaluation, as summarized in Table 2. For
each individual waste area which comprises Site A, reasonable maximum human exposures
were estimated for the following pathways:
~ Direct dermal (skin) contact with soils;
~ Incidental soil ingestion;
~ Air inhalation of dusts and vapors; and
~ Drinking water consumption.
Detailed exposure and toxicity assessments formed the basis for the characterization. of
chemical risks posed by Site A, using assumptions and methodologies defined by EP A
Exposure within each of the waste areas was represented by an occupational (industrial)
site use scenario, while residential exposures were assumed at the boundary of each area.
The individual and residential exposure scenarios were reasonable given the size of
individual areas which make up the site. Potential exposure pathways are depicted on
Figure 7. A summary of exposure factors used to compute chemical intakes is presented in
Table 3.
For carcinogens, the baseline risk is presented as the possible (upper-bound) risk of
contracting some form of cancer given lifetime exposure to a chemical. Federal guidelines
for acceptable upper-bound cancer risk range from a chance of 10-4 (1 in 10,000) to 10-6 (1
in 1,000,000) of developing cancer due to exposure to a carcinogen. The comparable
cancer risk range recognized by the Washington State Model Toxies Control Act (Chapter
173-340 WAC) is 10-5 to 10-6.
Non-carcinogenic risk is evaluated by dividing the daily dose resulting from site exposure by
the EP A estimate of acceptable intake (or reference dose) for chronic exposure. If the
ratio between these values (termed the Hazard Quotient) is less than 1, then non-
carcinogenic risks are not indicated. Conversely, Hazard Quotient values greater than 1
indicate a potential risk to human health.
The baseline lifetime cancer risks within each area of Site A were calculated for the
reasonable maximum exposure condition. The highest cumulative risk occurred in the
Burn Area (3 x 10-4 or 1 in 3,000), largely attributable to potential RDX exposures from a
hypothetical Shallow Aquifer drinking water well installed adjacent to this area. Chemical-
and pathway-specific risk calculations for the Bum Area are summarized in Table 4.
Calculated excess cancer risks at Debris Area 2 were 3 x 10-5, or 1 in 30,000. Calculated
cancer risks attnbutable to Debris Area 1 or the Stormwater Discharge Area were less
than 10-6 (1 in 1,000,000). Results of the baseline risk assessment are summarized in Table
s.
-------
.
,
.,' '. I.
Table 5. Summary of Baseline Cancer Risk Estimates at Site A
(Non-cancer Hazard Indices are presented in parentheses)
Exposure Area
Bum Area
Debris Area 1
Debris Area 2
Stormwater Area
Off-site Resident
II SoiJ/Dust Exposure ~ Groundwater Exposure
7 X 10-5 (4)
8 x 10-7 (0.03)
3 x 10-5 (0.5)
6 x 10-7 (0.04)
4 x 1
-------
t ."
.. '
. .
In addition to the human health risks discussed above, potential risks to sensitive aquatic
and terrestrial biota in the site vicinity were assessed in a screening-level ecological
evaluation. Risks associated with site discharges were assessed by comparing observed
water quality data with applicable state and federal ambient water quality standards.
Based on this analysis, no aquatic life risks attributable to any areas of Site A were
identified. Neither aquatic toxicity tests nor quantitative stream evaluations were
performed.
The potential impact of contaminants on terrestrial biota inhabiting the site vicinity was
also evaluated. This screening-level evaluation considered potential contaminant exposures
to four representative organisms identified during terrestrial surveys. The representaUve
organisms included a hawk, fox, deer, and vole (rodent). Semi-quantitative exposure
estimates were based on literature models and contaminant concentrations detected in
surface soil, vegetation, and surface water at Site A The exposure estimates were then
compared with conservative toxicity criteria largely developed to address human health
risks. Based on this comparison, potential risks to terrestrial wildlife were identified in
both the Burn Area and Debris Area 2. The primary risk identified in this screening-level
evaluation was associated with elevated lead concentrations present in soils at Debris Area
2.
Several wetland habitats and bird and mammal species of special concern are known to
occur within the general site vicinity. However, these critical habitat areas occur outside of
the remedial action area. No Natural Resources Damages issues have been identified at
the site.
The results of the baseline risk assessment indicate that the cumulative cancer risk
calculated for Site A exceeds the upper-bound Superfund guideline of 10-4, largely as a
result of potential exposure to RDX present in the Shallow Aquifer. Further, potential
non-cancer risks attnoutable to direct contact soil exposures at the Burn Area also exceed
human health criteria. Elevated lead concentrations present in soils at Debris Area 2 may
represent a potential ecological concern to sensitive species (e.g., rodents).
Based on these results, exceedence of CERCLA health-based thresholds is indicated for
both soil and groundwater at Site A, but only at the Burn Area. Actual or threatened
releases of hazardous substances from Site A, if not addressed by implementing the
response action selected in this ROD, may therefore present an imminent and substantial
endangerment to public health, welfare, or the environment.
8.0 CLEANUP STANDARDS
Qeanup objectives for Site A were developed based on results of the human health and
ecological risk assessments and applicable or relevant and appropriate requirements,
including the recently adopted (February 1991) Qeanup Standards Amendments to the
-------
. ,
"I' 'h
Washington State Model Toxies Control Act (MTCA; Chapter 173-340 WAC). The
MTCA standards utilize a combination of risk-based criteria and applicable state and
federal laws to derive site-specific cleanup levels. The MTCA standards have been
interpreted to be applicable to soil and groundwater cleanup actions at Site A, and were
generally more stringent than those calculated based on the site-specific risk assessment
discussed above. The MTCA cleanup levels are also relevant and appropriate as standards
for treated soil and water being returned onto or within the;: site. A comparison of site
conditions with MTCA Method B (standard method) cleanup levels is presented in Table 1
and is discussed below.
Surface Soil in the Bum Area. Surface soils of the Burn Area contain concentrations of
TNT and DNT which exceed applicable MTCA cleanup levels for direct soil contact
exposure, derived based on an assumption of future residential site use. Because of the
observed correlation between individual ordnance chemicals, the overall soil remedial
action objective can be expressed as a TNT concentration of approximately 30 mglkg.
Approximately 7,000 cubic yards of soil in this area exceed the MTCA cleanup level.
From an evaluation of the partitioning of contaminants between the surface soils, the
Perched Groundwater Zone, and the Shallow Aquifer, it is likely that the MTCA soil
cleanup level for protection of groundwater at Site A will be met by removing soil with
greater than 30 mg/kg TNT. As discussed in Section 10.0, this condition will be verified
through compliance monitoring of groundwater quality in the Perched Groundwater Zone
and the Shallow Aquifer, and will be addressed during the first five-year review.
Surface Soil in Debris Area 2. Similar to the Burn Area, surface soils in Debris Area 2
exceed the 30 mg/kg cleanup level for TNT. This same area also exceeds the range of
applicable soil lead cleanup levels (again assuming residential use) of 250 to 500 mglkg. In
consideration of potential ecological risks associated with lead exposures in this particular
area, the soil remedial action objective was set at the lower end of this range, 250 mglkg.
An estimated 100 cubic yards of soil at Debris Area 2 exceeds the cleanup level.
Stormwater Discharge from the Bum Area. Based on water quality data collected during
the remedial investigation of Site A, stormwater discharges from the Burn Area may
periodically exceed surface water quality criteria for some ordnance compounds such as
TNT and RDX. However, soil remediation to the 30 mglkg TNT cleanup level will reduce
the mass (and maximum concentrations) of TNT present on the site by approximately 95
percent, which should result in a similar reduction in on-site stormwater concentrations.'
Source controls will thus reduce TNT concentrations in waters discharged to this area to
below the MTCA cleanup levels.
Based on the correlation of TNT and RDX concentrations, a 90 percent reduction in the
mass of RDX in site soils is also expected from soil cleanup. Given these reductions, the
MTCA surface water cleanup levels (WAC 173-340-730[3]) will be achieved on-site
-------
.1' ',~
. .
following a soil cleanup action. Accordingly, no additional cleanup actions should be
necessary to achieve surface water quality criteria at Site A This condition will be
demonstrated through surface water compliance monitoring, once the soil cleanup action is
completed.
Perched Groundwater in the Bum Area. Some of the older perched groundwater 'wells at
Site A have TNT, DNT, and RDX at concentrations above MTCA groundwater cleanup
levels. However, the wells with the highest levels of these chemicals do not appear to have
competent seals to prevent down-hole contamination by surface water. Newer wells
completed in the Burn Area contain lower concentrations of most contaminants (except
RDX). Abandonment of the older monitoring wells, consistent with state regulations, is
identified as a general response action at Site A
With the exception of RDX, perched groundwater concentrations collected from newly
installed wells with proper surface seals are below MTCA groundwater cleanup levels.
However, current concentrations of RDX in the seasonal Perched Groundwater Zone
range from less than 0.1 to 61 ILg/L, which exceeds the MTCA Shallow Aquifer protection
criterion of 0.8 ILg/L (Table 1; WAC 173-340-720). The RDX concentrations detected in
the Perched Groundwater Zone also exceed the quantitation limit (PQL) of 5 ILg/L for this
compound as defined through EP A's Contract Laboratory Program.
As discussed in Section 6.3 above, RDX concentrations within the Perched Groundwater
Zone have declined over the past 10 years at an average rate of approximately 30 percent
per year. Concentrations measured in the Perched Groundwater Zone are also lower than
those detected in the underlying Shallow Aquifer. Based on both the historical monitoring
data and the results of contaminant transport modeling, there is greater than a 95 percent
probability that the 0.8 ILg/L MTCA criterion will be achieved throughout the Perched
Groundwater Zone before the year 2000, even in the absence of any remediation. Soil
cleanup (90 percent reduction in the soil mass of RDX) will speed the process.
As discussed in Section 9.2 below, the Perched Groundwater Zone is expected to be
remediated through a combination of source control (i.e., soil treatment) and groundwater
treatment of the Shallow Aquifer. Additional sampling is ongoing, and will continue, to
verify the expected reductions in RDX concentrations of the Perched Groundwater Zone.
Compliance with the MTCA groundwater protection criterion will be assessed with these
monitoring data, which will be reviewed within five years of commencement of the cleanup
action, consistent with the Federal Facility Agreement for SUBASE, Bangor.
Shallow Aquifer below the Bum Area. Concentrations of RDX above the MTCA
groundwater cleanup level have been detected in the Shallow Aquifer beneath the central
portion of the Burn Area. The maximum RDX concentration (189 ILg/L) detected in this
area is above the MTCA risk-based cleanup criterion (based on drinking water use) of 0.8
-------
. .
\I,' '" I.
p.g/L and the current POL of 5 p.g/L. The MTCA groundwater cleanup level is applicable
throughout the Shallow Aquifer.
Detections of RDX above the 0.8 p.g/L cleanup level have also been reported in areas
north of the Burn Area. However, these reported detections have nearly always been
below the current POL for RDX of 5 p.g!L Following procedures set forth in the MTCA
(WAC 173-340-707), compliance with the RDX cleanup level is considered to be attained
when concentrations are present below the POL Additional sampling of the Shallow
Aquifer is ongoing (using an improved low-level analytical method) to more precisely
define the boundary of RDX contamination in this area.
OfT-site Risks. Current off-site exposures in the community of Vinland are below MTCA
risk-based cleanup levels and within the range of acceptable risks defined under Superfund
and the MTCA Application of the soil cleanup level at the Burn Area (30 mglkg TNT)
will result in further reductions in the off-site risk. As stated above, monitoring of the
Shallow Aquifer upgradient of Vinland will continue as long as necessary in order to verify
that Vinland groundwater users are adequately protected.
9.0 DESCRIPTION AND COMPARISON OF ALTERNATIVES
9.1 50il Remediation Alternatives
The general response actions initially considered for soil remediation included the
following: Continued Monitoring; Institutional Controls; Containment; Removal;
Treatment; and Stabilization. Within each of these response actions, technologies were
identified which may be applicable to site remediation.
A wide range of soil remediation alternatives were initially identified for screening and of
these, five were subsequently selected for detailed analysis. The alternatives selected for
more detailed analysis included: No Action/Continued Monitoring; Limited Action; Cover;
Solidification; and Soil Washing. A detailed analysis was performed on each of these
alternatives. The following features were found to be common to all (except No
Action/Continued Monitoring):
Existing Controls. Site A currently has some control features in place. Institutional
controls include restrictions to site access. The Burn Area is enclosed with a chain-link
fence which is locked and posted with no-admittance signs. Containment features include
collection of surface water runoff from the Bum Area, and direction of these waters to the
Stormwater Discharge Area.
Long-Term Groundwater and Surface Water Monitoring. For those alternatives which
leave Burn Area soils on site without permanent treatment, long-term groundwater and
surface water monitoring would be conducted. Monitoring would continue for more than
-------
f II Ii
,.'
. '
30 years or until contaminant concentrations drop below specified remedial action
objectives.
Aspects unique to each of the five alternatives are presented below.
No Action
The No Action Alternative provides a baseline for comparing other alternatives. No
remedial activities would be conducted under this alternative.
Limited Action
In addition to the common items discussed above, the main component of this alternative
is a permanent Naval order preventing any future use of the site.
Soil Washine
The Soil Wash Alternative uses a three-step process. First, soils with contaminant
concentrations in excess of direct contact cleanup levels are excavated and placed in a lined
leach basin (treatment unit) constructed on site. The soil will be excavated to a depth of
approximately 1 foot and the site regraded and revegetated. The excavated soils will be
modified as necessary by mechanical or chemical means to ensure that the treatment
(washing) process will be effective and efficient. Second~ water is allowed to percolate
through the entire 7,100-cubic yard batch of contaminated soil to dissolve ordnance
chemicals from the soil and promote the migration of these contaminants with the leachate.
Filter layers on the bottom strain out the soil fines, and the leachate is collected from
below these filter layers.
The third and final component of the Soil Washing process is treatment of the leachate to
remove accumulated contaminants. Water treatment by natural photolysis, ultraviolet
(UV)/oxidation, or carbon adsorption is effective in removing ordnance from water. These
leachate treatment processes are also common to the groundwater extraction and
treatment alternatives. The leachate would be recirculated through the system, effectively
establishing a closed process, with no on-going discharge. Upon completion, the treated
soils will be left on site.
The effectiveness of the soil washing process for ordnance is well documented and has
been demonstrated in pilot-level studies performed at Site A and other similar sites (e.g.,
Site F). The solubility of these chemicals (panicularly RDX) in water is conducive to the
leaching of these materials from soil. Given proper design, the washing process could
reduce soil contaminant concentrations within the Burn Area to achieve MTCA cleanup
levels within a time period of one year from start of the soil washing operation.
-------
"""""1:~"
.
.
. r ,.
'.
All three leachate treatment options (natural photolysis, UV/oxidation, and carbon
adsorption) have been shown to be effective in reducing the concentrations of "parent"
ordnance products such as TNT and RDX to levels which will allow treatment of soils to
below MTCA cleanup levels. However, the natural photolysis option can, under some
conditions, result in the formation of potentially toxic ordnance by-products. The
effectiveness of the various leachate treatment options is discussed further under the
Groundwater Remediation section of this ROD (Section 9.2).
Under this alternative, the limited quantities of soil (100 cubic yards) at Debris Area 2
which exceed direct contact cleanup levels will also be excavated and placed within a
separate cell in the Soil Washing basin constructed at the Burn Area. Although ordnance
contaminants present in the Debris Area 2 soils will be treated by this process, the Soil
Washing process is not effective in reducing lead concentrations, which are only found
above-action levels at Debris Area 2. Nevertheless, following the MTCA regulations
(WAC 173-340-360[5]), the lead expected to remain in these soils following completion of
the soil washing is considered a residue from a permanent treatment process. These soils
will be disposed of at a permitted off-site landfill.
Cover
The main component of the Cover Alternative is a 130,000-square-foot low permeability
geomembrane cap constructed over the contaminated soil. Soils in the northern and
southern portions of the Burn Area which exceed direct contact cleanup levels, along with
burn mound and Debris Area 2 soils, will be relocated to beneath the cap area. The cap
slope will conform approximately to the existing site slope - about 5 percent. Shallow-
rooted vegetation will be planted on the surface of the cap to prevent erosion. Future land
use within the immediate vicinity of the capped area of Site A will still be restricted by
deed.
Solidification
The primary component of this alternative is solidification of soil exceeding the direct
contact cleanup level to an in situ depth of 1 foot. The solidification reagent type and
quantity will be determined during final design, although common components include
Portland cement, fly ash, kiln dust, and lime. To protect the solidified mass from
weathering, it will be covered with 18 inches of soil and the surface revegetated with grass.
Future land use at Site A will still be restricted by deed in the immediate vicinity of the
solidified soils.
9.2 Groundwater Remediation Alternatives
Similar to the soil remediation, a wide range of groundwater cleanup alternatives were
initially identified for screening, and of these four were subsequently selected for detailed
-------
. . u
. I
. .
analysis. The alternatives selected for more detailed analysis included: No Action; Pump
and Treat by Natural Photolysis; Pump and Treat by UV/Oxidation; and Pump and Treat
by Carbon Adsorption.
A feature common to all of the groundwater alternatives is the assumed cleanup of the
Perched Groundwater Zone through the (natural) flushing of the single identified
groundwater contaminant (RDX) into both Vinland Creek and the Shallow Aquifer.
Existing releases of RDX into Vinland Creek do not exceed MTCA surface water cleanup
levels.
Remediation of the perched zone sufficient to achieve underlying aquifer protection.
criteria, defined under the MTCA, is expected to occur (naturally) within a five- to ten-year
period, even in the absence of any cleanup action. The restoration time frame will be
substantially shortened as a result of the soil cleanup action. Compliance with the MTCA
groundwater protection criterion will be asseSsed with monitoring data, which will be
reviewed within five years of commencement of the cleanup action, consistent with the
Federal Facility Agreement for SUBASE, Bangor.
Restoration of the aquifer to be protected (the underlying Shallow Aquifer) will also likely
require a to-year restoration time frame (see below). Testing of the both the Perched
Groundwater Zone and Shallow Aquifer will be conducted throughout this period to ensure
that the cleanup proceeds as predicted. As part of the first five-year review of the overall
site groundwater cleanup the need for additional restoration of the Perched Zone will
evaluated. Alternatives to be considered in this case include introduction of treated
groundwater into the Perched Zone, as outlined below.
The No Action Alternative would not include any construction activities. However, long-
term groundwater monitoring (more than 30 years) would be necessary to ensure that site
groundwaters do not pose excessive risks to Vinland groundwater users.
Detailed analyses were performed for each of the three aquifer restoration alternatives.
The following features were found to be common to all:
Well Abandonment. Groundwater monitoring wells previously installed by the Navy at Site
A may be functioning as conduits for vertical migration of contaminants. All such wells will
be abandoned, in accordance with the methods descnbed in the Washington Administrative
Code (Chapter 173-160 WAC) or as approved by Ecology. Well abandonment methods
will include perforating the PVC well casing and pressure grouting with bentonite to create
an effective seal and barrier to vertical migration of contaminants. The sealed wells will be
capped with a concrete plug at the ground surface.
Groundwater ExtractionlReintroduction. Based on the results of numeric contaminant
transport modeling of the Shallow Aquifer system, groundwater extraction without
-------
.
,
\8 ~ '...
reinjection would require a time frame of more than 10 years to achieve the MTCA
cleanup level of 0.8 p.g/L RDX. This rate was judged too slow for implementation of an
effective aquifer restoration program. However, by combining groundwater extraction with
reintroduction of the treated water into the Shallow Aquifer, the rate and efficiency of
restoration can be increased substantially.
Groundwater restoration alternatives involving extraction and reintroduction were
evaluated using mathematical models developed by the U.S. Geological Survey (Method of
Characteristics) to simulate groundwater flow and contaminant transport conditions. Input
to the model was based on a number of conservative parameter values, including the
assumption that the entire Shallow Aquifer beneath the Burn Area contains RDX at the
highest concentration observed (189 p.g/L). Because of conservative input values, use of
the model is expected to generally overestimate the number of wells and flow rates
required to achieve the cleanup levels. Additional groundwater monitoring is ongoing to
refine the extent of RDX contamination in the Shallow Aquifer.
Based on the results of the modeling, a remediation design utilizing a well grid spacing of
100 feet between extraction and reintroduction well pairs would likely achieve the
groundwater cleanup level for RDX (0.8 p.g/L) within a restoration time period of 10 years.
An estimated total of 8 extraction and 15 injection wells, pumping a combined flow of
approximately 12 gallons per minute, appears from this analysis to represent a feasible
cleanup option. Largely because of the low permeability of the Shallow Aquifer material,
accelerated cleanup using a larger number of wells would not be practicable. A conceptual
layout (including number of wells) of the extraction and reintroduction system is presented
on Figure 8. Further refinement of the layout will be required for final design.
As discussed above, in the unlikely event that the first five-year review reveals that
substantial progress in remediating the Perched Groundwater Zone to the 0.8 p.g/L Shallow
Aquifer protection criterion has not been made, an additional component of the
groundwater remediation will be considered. Alternatives to be considered would include
installation of infiltration systems in the upper Recessional Outwash deposits to provide
additional flushing of the Perched Groundwater Zone into the Shallow Aquifer.
Reintroduction rates would be controlled to optimize flushing conditions.
Aspects unique to each of the alternatives are presented below.
Pump and Treat bv Natural Photolysis
Natural photolysis will expose site groundwaters to natural sunlight to accomplish ordnance
degradation. The alternative Will include construction of a 1 million-gallon impoundment
within the Burn Area sufficient to achieve a water residence time within the basin of 1 to 2
months. Based on literature reports of the rapid decay of compounds such as TNT and
RDX in surface waters (half-lives on the order of one to ten days), considerable photolytic
-------
. '.
-' I
, '
degradation can be expected. However, this technology has never been evaluated for
treatment at the scale required at Site A Further, potentially toxic by-products can be
formed under some conditions. Minor atmospheric releases of ordnance may occur under
this alternative.
Because natural photolysis is still an innovative technology, some additional laboratory
testing of the treatment system will be necessary to verify that the treatment system is
effective in removing all potential chemical toxicants in Site A groundwaters. If the
groundwater treatment criteria are not achieved with the natural photolysis system, then
additional treatment technologies (polishing treatment) will be incorporated into the
treatment design to achieve the treatment criteria.
Pump and Treat by UVIOxidatWn
Ultraviolet (UV)/Oxidation treatment has been applied in pilot-scale and small field-scale
applications to break apart complex organic chemicals and convert them into components
such as carbon dioxide, water, and nitrate. Although relatively minor quantities of RDX
by-products can be formed under some UV/Oxidation treatment conditions (e.g., formic
acid), the treatment system can generally be optimized to prevent the formation of
potential toxicants.
Because UV/Oxidation is still an innovative technology, some additional laboratory testing
of the treatment system will be necessary to verify that the treatment system will be
effective in removing all potential chemical toxicants in Site A groundwaters. Treatability
studies using UV/Oxidation are currently being performed to verify that the treatment
system will be effective at treating low level concentrations of ordnance under the
conditions which exist at Site A The available information suggests that a UV/Oxidation
system can be designed which will achieve the required treatment levels for groundwater
disposal. No toxic air emissions are anticipated under this alternative.
If the groundwater treatment criteria are not achieved with the UV/Oxidation system due
to either technological or economic reasons, then additional treatment technologies
(polishing treatment) will be incorporated into the treatment design to achieve the
treatment criteria.
Pump and Treat by Carbon Adso1J1tion
The Carbon Adsorption Alternative will involve a proven treatment process which can
attain all cleanup levels. In this case, however, the contaminants are initially transferred
from the water to the carbon solid phase. This alternative will generate spent carbon
waste requiring transport and off-site disposal by incineration. Although no on-site air
emissions are anticipated under this alternative, off-site releases can occur during final
incineration and treatment of the spent carbon.
-------
. . ~. ..
, L.r
10.0 COMPARATIVE ANALYSIS OF ALTERNATIVES
Each of the soil and groundwater remediation alternatives discussed above were evaluated
against the nine criteria established by EPA guidelines. The No Action Alternative was
included as a baseline comparison. The following sections evaluates the alternatives by the
nine applicable criteria, with separate comparisons of soil and groundwater alternatives.
10.1 Evaluation o[ Soil Remediation AlJernatives by Criteria
OveraU Protection of Human Health and the Environment
All of the alternatives except No Action provide adequate protection of human health.
Existing institutional controls are used in the Limited Action Alternative to prevent
exposure. Ecological risks, as defined by the risk assessment, will be adequately protected
under all alternatives except No Action and Limited Action.
Compliance with ARARs
The MTCA cleanup regulation does not recognize institutional controls as a substitute to
cleanup actions which would otherwise be technically possible. Accordingly, both the No
Action and Limited Action Alternatives will not comply with applicable or relevant and
appropriate requirements (ARARs). The remaining alternatives will achieve ARARs.
Soils at Site A do not exceed designation criteria for characteristic dangerous (state) or
hazardous (federal) wastes, and are not listed hazardous wastes. Thus, dangerous and
hazardous waste handling, treatment, and disposal requirements (e.g., Land Ban
restrictions) are not ARARs for soil remediation.
Lone. Term Effectiveness and Permanence
The Soil Wash Alternative provides the most reliable long-term performance because it
uses treatment to permanently reduce the risks from site contaminants. No long-term
maintenance is required for this alternative, although groundwater monitoring will occur
during the treatment period to detect leaks in the treatment basin liner system.
The Cover Alternative will use a membrane cap to reduce human and wildlife exposure to
contaminated soils; the cap will be effective in the long-term with proper maintenance.
The Limited Action Alternative will rely upon institutional controls to prevent human
exposure; its long-term effectiveness will depend on compliance with the access and land-
use restrictions. However, the Limited Action Alternative cannot address possible
ecological risks. The Solidification Alternative will immobilize the contaminants, and the
stabilized soil should remain intact in the long-term.
-------
, .,
, ,
,
. ,
Reductions in Toxicity. Mobility. and Volume throu~h Treatment
The Soil Wash Alternative will reduce toxicity of the soil through treatment. The
Solidification Alternative will use stabilization to reduce the mobility of contaminants.
None of the other alternatives use treatment technologies.
Shorl- Term Effectiveness
During remedial construction activities, human exposure to contaminated soils and dusts
may occur at levels greater than baseline conditions. However, based on the results of the
risk assessment, potential human health and ecological risks arising from short-term .
construction activities (due to unmitigated dust generation and inhalation) are not
identified as a health concern. There may be some elevated noise levels during
construction. Construction activities will be designed to minimize these potential short-
term effects, where possible. .
The Limited Action Alternative has the greatest short-term effectiveness since no work will
be done with contaminated soil; site access restrictions could be implemented almost
immediately. The Cover and Solidification Alternatives will achieve protection within
about 6 months. The Soil Wash Alternative will result in the contaminated soil being
contained within about three months; the treatment will be complete within about one
year, depending upon final design. (The estimated completion times are based on time
from start of implementation.)
Implementability
The Limited Action Alternative will be the simplest to implement. There are no special
requirements. Access restrictions could be easily expanded to accommodate any additional
contamination identified at the site.
The Cover and Solidification Alternatives will use standard construction techniques. These
alternatives have no operational requirements. Solidification is more complex because of
the stabilization process. Bench testing will be required during final design to determine
which combination of stabilization additives will result in appropriate reductions in
contaminant mobility.
The Soil Wash Alternative also uses standard techniques to construct the leach basin.
Excavated soils may require modification by mechanical and/or chemical means, prior to
placement in the leach basin, to ensure effective and efficient operation. This alternative
also requires operation of a treatment system, which will require regular monitoring and
maintenance. Alternative treatment systems include Natural Photolysis, UV/Oxidation, and
Carbon Adsorption which vary in their implementability, as discussed under the
-------
\ ,'~ "
groundwater remediation options. The operation may require adjustment or modification
based on actual performance.
Cost
The cost of each soil/surface water cleanup alternative, in order of increasing present
worth, is shown below:
Alternative
Present
Worth Cost
No Action
Limited Action
Soil Wash
Cover
Solidification
$ 670,000
800,000
890,000.
1,530,000
1,850,000
.Note: The estimated present worth cost for the Soil Wash Alternative does not include
treatment costs, since the treatment methods are also common to groundwater remediation
alternatives, as presented below.
State Acceptance
The State of Washington Department of Ecology concurs with the selected remedial action
at Site A Comments received from Ecology have been incorporated into this Record of
Decision.
Community Acceptance
Public comments were received during the public review period and at the public meeting.
The public presented no significant objection to the proposed plan which is now the
selected remedy. The attached Responsiveness Summary contains the public's comments
and the agency's responses.
10.2 Evaluation 01 Groundwater Remediation Alternatives by Criteria
Under all alternatives except No Action, construction activities necessary to implement
groundwater restoration will occur on or immediately adjacent to the Bum Area. No
construction will occur off-base.
-------
, . I
.' ,
, ,
Overall Protection of Human Health and the Environment
Under the No Action Alternative (as evaluated in the baseline risk assessment), potential
cancer risks resulting from exposures to RDX exceed 10-4. However, existing institutional
controls presently prevent consumptive use of groundwaters in this area. All three
treatment alternatives considered (Natural Photolysis, UV/Oxidation, and Carbon
Adsorption) are capable of reducing concentrations of the target contaminants (e.g., RDX
and TNT) to levels below the MTCA cleanup levels. However, under the Natural
Photolysis Alternative, potentially toxic by-products can be formed (under some conditions)
which could be reintroduced into the Shallow Aquifer. Effiuent polishing may be required
in this case to achieve adequate protection of public health.
Compliance with ARARs
All three treatment alternatives would satisfy all ARARs, including action-specific and
chemical-specific provisions of the MTCA Oeanup Standards. The No Action Alternative
does not meet these ARARs.
The three treatment alternatives include the reintroduction of groundwater into the
Shallow Aquifer. Provisions of the state groundwater quality standards (WAC 173-200) are
applicable chemical-specific treatment standards for water discharged to the aquifer. The
treatment standard for RDX as promulgated by the groundwater quality standards is 0.8
p.g/L, identical to the relevant and appropriate MTCA groundwater cleanup level (WAC
173-340- 720). The treatment technology for the extracted groundwater under all treatment
alternatives will meet these ARARs. Requirements of the State Minimum Standards for
Construction and Maintenance of wells (WAC 173-160), are applicable action-specific
ARARs for the design of extraction and compliance monitoring wells. Re-introduction
wells will conform with the Oass V designation (aquifer remediation well) under the
Underground Injection Control Program (WAC 173-218).
Lone- Term Effectiveness and Permanence
The long-term effectiveness of existing institutional controls under the No Action
alternative can be assured as long as the land downgradient of Site A (toward Cattail
Lake) remains under the control of SUBASE. The treatment alternatives will provide
long-term effectiveness because they use permanent treatment methods.
Reductions in Toxicity. Mobility. and Volume throufh Treatment
All treatment alternatives reduce the toxicity of target site contaminants such as RDX.
However, under the Natural Photolysis Alternative, potentially toxic by-products could be
formed (under some conditions) which may be reintroduced into the Shallow Aquifer.
-------
, ,
,. ,
, '.
The UV/Oxidation and Carbon Adsorption Alternatives differ in the method used to
reduce the toxicity and volume of contaminants. UV /Oxidation treatment will provide final
treatment and thus primary reduction in toxicity and volume of contaminants.
Alternatively, Carbon Adsorption treatment will provide removal of contaminants from the
groundwater to the carbon, thus effecting a reduction in toxicity and volume of
contaminants in the groundwater. The carbon will then require final off-site treatment by
incineration.
Short- Term Effectiveness
During remedial construction activities, human exposure to contaminated soils and.
groundwater may occur at levels greater than baseline conditions. Such exposures will be
mitigated by the use of protective gear during construction activities when potential
exposure conditions exist.
All of the treatment alternatives can be commenced within a IS-month period after Record
of Decision signature. However, the implementation schedule for the Natural Photolysis
and UV/Oxidation Alternatives are predicated on successful completion of treatability
studies. The groundwater treatment alternatives will require an estimated 10 years to
complete (minimum several years).
During operation of groundwater remediation, further spreading of contaminants in the
groundwater will be prevented, thereby protecting any potential downgradient water
supplies.
Implementability
Of the three treatment alternatives, Carbon Adsorption is the least implementable because
of the present limitation of facilities which handle disposal of the spent carbon. Both the
UV/Oxidation and Natural Photolysis Alternatives will require a treatability study to verify
that the treatment systems are effective. The UV/Oxidation treatability study has already
commenced.
Cost
The cost of each groundwater cleanup alternative, in order of increasing present worth, is
shown below:
-------
.' t :' ,/
Alternative
Present
Worth Cost
No Action
Pump and Treat by:
Natural Photolysis
UV/Oxidation
Carbon Adsorption
$ 670,000.
1,150,000
1,810,000
3,450,000
~ote: The estimated present worth cost for the No Action Alternative is a duplication of
the No Action Alternative presented previously.
State Acceptance
The State of Washington Department of Ecology concurs with the selected remedial action
at Site A Comments received from Ecology have been incorporated into this Record of
Decision.
Community Acceptance
Public comments were provided during the public review period and at the public meeting.
The public presented no significant objection to the proposed plan which is now the
selected remedy. The attached Responsiveness Summary contains the public's comments
and the agency's responses.
11.0 THE SELECTED REMEDY
The alternative selected for the remedial action at Site A includes Soil Washing with
UV/Oxidation treatment and groundwater restoration, also with UV/Oxidation treatment.
This combined alternative is preferred because it best achieves the goals of the evaluation
criteria in comparison to the other alternatives. The leachate and groundwater treatment
method selected - UV/Oxidation - employs aD. innovative technology that provides on-site
treatment with permanent reduction in the toxicity, mobility, and volume of ordnance
contaminants. Both phases of the remediation (i.e., soil and groundwater cleanup) will
likely utilize the same general UV/Oxidation treatment system sequentially.
The remedial action plan, which will cost an estimated $2,700,000 (present worth) includes
the following actions:
Well Abandonment:
. Immediately abandon all older monitoring wells which may not have competent surface
seals.
-------
, \ ' ~ '1.
Soil Remediation:
~ Excavate approximately 7,000 cubic yards of soil from the Burn Area which exceeds
MTCA direct contact cleanup levels for ordnance (33 mglkg TNT; 1.5 mglkg DNT; and
9.1 mglkg RDX). Excavate soils from Debris Area 2 which also exceed these action
levels and/or 250 mglkg lead. The excavated soils will be modified as necessary by
mechanical or chemical means to ensure that the subsequent treatment (washing)
process will be effective and efficient. Place all such soils in a Soil Washing basin
constructed at the Site A Burn Area. The soils from Debris Area 2 with lead
concentrations exceeding 250 mg/kg will be placed in a separate cell in the soil washing
basin. The basin will include a synthetic membrane liner to prevent escape of the
leachate. Construction details of the Soil Washing basin will be detemrined during final
design.
~ Conduct verification monitoring during and/or following the excavation to assure that all
soils exceeding the cleanup levels have been excavated. The point of compliance shall
be throughout the Bum Area and Debris Area 2. Evaluate compliance with the
cleanup standards using compliance monitoring procedures defined in WAC 173-340.
~ Pending successful completion of the ongoing treatability study and subsequent final
design, perform soil washing on soils placed in the treatment basin, treating the
leachate with a UV/Oxidation treatment system. Recycle the treated water back to the
leach basin (zero discharge). Although the soil treatment process is expected to be
completed within approximately one year, th~re is a possibility that a longer time frame
may be required to achieve the cleanup levels. In this case, continuation or
modification of the soil washing may be addressed during the first five-year review of
the cleanup action, in accordance with the Federal Facility Agreement for SUBASE,
Bangor.
~ Treatment will be considered completed when soils within the basin are below the
MTCA direct contact cleanup levels for ordnance (33 mg/kg TNT; 1.5 mglkg DNT; and
9.1 mglkg RDX) and when the RDX concentration in the treated leachate is less than
the MTCA groundwater protection level for RDX of 0.8 p.g!L. Treatment will also be
considered complete if the treated leachate concentrations are below updated PQLs.
Compliance with the cleanup standards will be determined using compliance monitoring
provisions defined in WAC 173-340.
~ Upon completion of the soil washing, the basin, liner, and soil contents will all be
abandoned in place. A one-foot soil cover will be placed over the treated materials,
and revegetated to prevent erosion. The site will be graded to allow for surface water
drainage including drainage from the abandoned leach basin. Those Debris Area 2
soils which still contain lead concentrations above 250 mglkg after treatment will be
excavated and disposed of at a permitted off-site solid waste facility.
-------
.,' : I I 1
Groundwater Remediation:
~ Following completion of the soil treatment action, groundwater protection will be
assessed by monitoring ordnance concentrations in the seasonal Perched Groundwater
Zone immediately underlying the Burn Area. The point of compliance for comparison
with state groundwater protection (drinking water use) levels will be established
throughout the Perched Zone. If compliance with state groundwater protection criteria
has not been achieved within five years from commencement of this action,
modifications to the groundwater remediation system will be considered, as discussed in
Section 11.1.
~ Concurrent with the soil washing, conduct additional groundwater monitoring and pilot-
level treatability studies to support final design of the groundwater restoration program.
The restoration program shall initially be designed to achieve the MTCA groundwater
cleanup level for RDX of 0.8 p.g/L in the most cost-effective manner within a 10-year
period of operation. The point of compliance will be throughout .the Shallow Aquifer.
~ Pending final design, the groundwater restoration program will include the installation
of approximately 8 extraction wells within the vicinity of the Burn Area. The system
will operate at a combined flow of approximately 12 gallons per minute. Extracted
groundwater will be treated using UV/Oxidation to reduce RDX concentrations to less
than 0.8 p.g/L or the updated PQL, whichever is greater. In the unlikely event that the
results of the treatability study or system performance monitoring data reveal
inadequate treatment, there may be a need to install an effective effluent polishing
process in order to achieve the treatment standards. Treated groundwater will be
reintroduced on site through approximately 15 reinjection wells, configured to facilitate
maximum flushing of the aquifer.
~ As with any groundwater remediation, the effectiveness of the Shallow Aquifer
restoration program at Site A will be continuously monitored and evaluated as a
component of operation and maintenance, as discussed below. System operation will
cease when it can be demonstrated either that the cleanup standards have been met or
that continued operation is no longer practicable, following evaluation criteria defined
in WAC 173-340.
Technical analyses, as presented in the Final RIIFS for Site A, have shown that Soil
Washing combined with UV/Oxidation treatment of the leachate is feasible and effective in
permanently removing and destroying ordnance constituents present in soils. The RIIFS
analyses have also demonstrated that groundwater restoration through extraction,
UV/Oxidation treatment, and reintroduction should be feasible, though additional data are
needed to support final design and implementation.
-------
, \ 1 ~ .., I.
iF
The cancer risk levels corresponding to the MTCA (Method B) cleanup levels which are
the goal of the site cleanup are 1 x 10~ for individual hazardous substances and 1 x 10-5 for
cumulative exposures to multiple hazardous substances and routes of exposure. The
cumulative Hazard Index for multiple hazardous substances and routes of exposure is 1.
The reasonable maximum exposure assumptions used to derive the MTCA cleanup levels
are equivalent or more stringent than the federal Superfund requirements. These
standards are within acceptable EP A (NCP) risk criteria.
11.1 Groundwater Remedial Action Measures and Goals
The goal of the groundwater remedial action is to restore Shallow Aquifer waters to.
support possible future drinking water use. Based on information obtained during the RI,
and the analysis of all remedial alternatives, the Navy, EP A, and Ecology believe that the
selected remedy should be able to achieve this goal. However, the ability to achieve
groundwater cleanup levels at all points throughout the Shallow Aquifer at Site A cannot
be determined until a detailed design of the extraction and reintroduction system has been
completed, and the system has been implemented, modified as necessary, and the
groundwater plume monitored over time.
The selected remedy will include groundwater extraction, treatment, and reintroduction for
an estimated period of 10 years, during which time the system's performance will be
carefully monitored on a regular basis and adjusted as warranted by the performance data
collected during operation. Modifications may include any or all of the following:
~ Discontinuing pumping at individual wells where cleanup goals have been attained;
~ Alternating pumping wells to eliminate stagnation points;
~ Pulse pumping to allow aquifer equilibrium and encourage adsorbed contaminants to
partition into groundwater; and
~ Installing additional extraction and/or reintroduction wells in either the Perched
Groundwater Zone or Shallow Aquifer to facilitate or accelerate cleanup of
groundwater contaminants.
Remedial actions which allow hazardous substances, pollutants, or contaminants to remain
on-site must be reviewed not less than every five years after initiation, to ensure the
remedy continues to be protective of human health and the environment. Such a review
would be conducted in accordance with Part XIX (5 year review) of the Federal Facility
Agreement for SUBASE, Bangor. These reviews may result in further modification of the
treatment process, consideration of other remedial approaches or revision of the cleanup
standards. Changes to the selected remedy or cleanup standards would require formal
notification to the public.
-------
\0 I' ~ f I 1
11.2 Effectiveness of Treatment Technology
Ultraviolet/Oxidation (UV/Oxidation) is the selected treatment technology for ordnance
contaminants present at Site A It is an innovative technology which has been shown to be
successful in treating complex organic compounds, including RDX and TNT.
Combined use of UV with strong oxidants such as ozone and hydrogen peroxide" has
developed into a successful technology for treating refractory organics in industrial
wastewater. UV-catalyzed oxidation, or UV/Oxidation has also been applied to treatment
of groundwater contaminants including ordnance compounds.
The basis of enhanced oxidation is the use of UV light and an oxidant source such as
ozone 'or hydrogen peroxide to generate a hydroxyl radical. The hydroxyl radical will
aggressively attack and break down complex organic compounds (such as ordnance) by
initiating a series of oxidative reactions, converting them into components such as carbon
dioxide, water, and nitrate. Although relatively minor quantities of ordnance by-products
(e.g., formic acid) can be formed under some UV/Oxidation treatment conditions, the
treatment system can generally be optimized to prevent the formation of potential
toxicants. Monitoring will be performed throughout implementation of the treatment
process to ensure that potential toxicants are not being formed.
The UV/Oxidation technology has been shown to be effective on munitions; however, the
application at Site A may require treatment of very low levels of ordnance at a moderate
flow rate. Prior studies have been conducted at a level of treatment which was not as
stringent as that planned for Site A A treatability study is currently on-going to verify that
the treatment system is effective in meeting the low-level treatment and flow rate
requirements of this remedial action at Site A
If the UV /Oxidation process cannot achieve treatment levels down to the desired criteria
due to either technological or economic reasons, then an on-site polishing (e.g., activated
carbon) treatment will be coupled with the UV/Oxidation system to complete the treatment
process prior to disposal.
12.0 STATUTORY DETERMINATION
The Navy's and EP A's primary responsibility, under their legal CERCLA authorities, is to
ensure that remedial actions will protect human health and the environment from the
exposure pathways or threat it is addressing and the waste material being managed.
Additionally, Section 121 of CERCLA, as amended by SARA, establishes several other
statutory requirements and preferences. These specify that, when complete, the selected
remedial action must comply with applicable or relevant and appropriate environmental
-------
,) , ~ '\!..'
standards established under federal and state environmental laws unless a statutory waiver
is justified. .
The selected remedy also must be cost-effective and utilize permanent solutions and
alternative treatment technologies or resource recovery technologies to the maximum
extent practicable. The remedy should represent the best balance of tradeoffs among
alternatives with respect to pertinent criteria. Finally, the statute includes a preference for
remedies that employ treatment that permanently and significantly reduce the volume,
toxicity, or mobility of hazardous wastes as their principal element.
The selected remedial action for Site A at SUBASE, Bangor meets these statutory
requirements for both soil and groundwater.
12.1 . Protection 0/ Human Health and the Environment
The selected remedial action will protect human health and the environment through
extraction and treatment of ordnance in soils and groundwater. The treatment standards
support the highest beneficial use of these media (i.e., residential land use and water
supply), and is protective of human health and the environment. The ordnance
contaminants will be permanently removed from the soil and groundwater through the
treatment process which includes destruction by ultraviolet light and oxidation. As
necessary, the effluent from the groundwater treatment process will be further treated by a
polishing treatment to ensure that the disposed water does not constitute an unacceptable
potential risk to human health and the environment.
12.2 Compliance with Applicable or Relevant and Appropriate Requirements
The selected remedy will comply with all applicable or relevant and appropriate chemica1-,
action-, and location-specific requirements (ARARs). The ARARs are presented below.
12.2.1 Action-Specific ARARs
~ State of Washington Hazardous Waste Oeanup - Model Toxies Control Act (Chapter
70.10SD RCW) establishes requirements for the identification, investigation, and
cleanup of facilities where hazardous substances have come to be located as codified in
Chapter 173-340 WAC.
~ Requirements of the State of Washington for water well construction as set forth in
Chapter 18.104 RCW (Water Well Construction) and codified in Chapter 173-160
WAC (Minimum Standards for Construction and Maintenance of Wells), establishes
criteria for the construction of extraction and compliance monitoring wells. Criteria for
-------
,I' ~, ,I
Oass V re-introduction wells are set forth in Chapter 90.48 RCW and codified in
Chapter 173-218 WAC.
. The State of Washington has established requirements for control of fugitive dusts and
other air emissions during excavation and cleanup related activities, as codified in
Chapter 173-400-040 WAC.
. The State of Washington has established safe operating procedures and requirements
for hazardous waste operations conducted at uncontrolled hazardous waste sites, as set
forth in WAC 296-62 (Part P).
. Federal Oean Water requirements for discharge of treatment system effluent to the
waters of the United States, as set forth in 40 CFR 122, establish design standards for
wastewater treatment units.
. Water Pollution Control Act (Chapter 90.48 RCW) and Water Resources Act of 1971
(Chapter 90.54 RCW) require the use of all known available and reasonable methods
(AKARMs) for controlling discharges to surface water and groundwater.
. The State of Washington Hazardous Waste Management Act (Chapter 70.105 RCW)
establishes requirements for dangerous waste and extremely hazardous waste as
codified in Chapter 173-303 WAC and may apply depending upon any treatment
residuals created. No dangerous wastes have been identified to date.
12.2.2 Chemical-Specific ARARs
Soil and groundwater remediation activities will meet the following chemical-specific
ARARs:
. State of Washington Hazardous Waste Qeanup - Model Toxies Control Act (MTCA;
Chapter 70.105D RCW) establishes requirements for the identification, investigation,
and cleanup of facilities where hazardous substances have come to be located as
codified in Chapter 173-340 WAC. Soil and groundwater cleanup standards established
under the MTCA are applicable for determining remediation areas and volumes and
compliance monitoring requirements, and are relevant and appropriate for determining
treatment standards.
. State of Washington Groundwater Quality Standards (WAC 173-200) are applicable
chemical-specific standards for water discharged to the aquifer.
. Oean Water Act Section 402 (40 CFR Parts 121-125) and State of Washington Chapter
173-220 WAC (NPDES Permit Program) for effluent discharge may be applicable if
effluent is discharged to surface water.
-------
\ \ ' ~ 'I,
~ Ambient concentrations of toxic air contaminants are regulated pursuant to the State of
Washington Oean Air Act (Chapter 70.94 RCW) and Implementation of Regulations
for Air Contaminant Sources (Chapter 173-403 WAC).
12.2.3 Location-Specific ARARs
There are no location-specific ARARs for this action.
12.2.4 Land Disposal Restrictions
The selected remedy will not involve the placement of RCRA hazardous wastes on site.
This being the case, the Land Disposal Restrictions will not apply. However, off-site
disposal policy and transportation/manifest requirements are applicable to disposal of
treated Debris Area 2 soils at an off-site permitted landfill.
12.2.5 Other Criteria. Advisories. or Guidance To-Be-Considered fTBC' .
No other criteria, advisory, or guidance are considered necessary for implementation of this
remedial action.
12.3 Cost Effectiveness
The selected Remedial Action is cost-effective because it is protective of human health and
the environment and attains ARARs, and its effectiveness in meeting the objectives of the
selected remedial action is proportional to its cost. The selected remedy is comparable in
cost to many of the other possible combinations of alternatives. Howe~er, it employs the
use of an innovative treatment technology and will result in the on-site destruction of
contaminants and recharge of the extracted and treated groundwater to replenish
groundwater supplies. The selected remedy can be implemented in the short-term. The
use of carbon adsorption technologies would require off-site treatment where the efficiency
of the destruction process could not be assured. The selected remedy provides a much
higher degree of certainty that the remedy will be effective in the long-term due to the
significant reduction in toxicity, mobility, and volume of wastes through the treatment
process.
12.4 Utilization 01 Permanent Solutions and Alternative Treatment Technologies
or Resource Recovery Technologies to the Maximum Extent Practicable
The Navy, the State of Washington, and the EP A have determined that the selected
remedy represents the maximum extent to which pennanent solutions and treatment
technologies can be used in a cost-effective manner for Site A The selected remedy will
-------
.' I ~ I I i
result in maximum on-site destruction of contaminants and recharge of the extracted and
treated groundwater to replenish groundwater supplies.
12.5 Preference for Treatment as Principal Element
By treating the ordnance contaminants present in soil and groundwater media, the statutory
preference for remedies employing treatment as a primary element is achieved. The
selected remedy will result in maximum on-site destruction of contaminants in both soil and
groundwater.
sn:EA.IXX:
-------
Table I - Summary of Chemicals of Concern
TNT Total - DNT RDX
Soils Concentration in mglkg
Bum Area <0.1-1,300 <0.2-20 <30
Debris Area 2 <0.4-72 <0.5-1.1 <0.4-1.3
All Other Areas <0.4 <0.2 <0.3
MTCA Soil Cleanup Level
Direct Contact (a) 33 1.5 9.1
Groundwater Protection (b) 0.29 0.001 0.08
Surface Water Concentration in ug/L
Bum Area Stormwater <10-140 <0.1-0.3 < 1-39
Hood Canal Seepage <0.1-0.9 <0.1 0.1-17
All Other Surface Waters <0.1-0.3 <0.1-0.3 <0.1- 3
MTCA Surface Water Cleanup Level 31 0.6 30
Groundwater Concentration in uglL
Burn Area Perched Groundwater Zone (c) <0.6 <0.1 <0.1-61
Burn Area Shallow Aquifer <0.6 <0.1 <0.1-189
All Other Groundwater <0.6 <0.1 <0.1-7
MTCA Groundwater Cleanup Level 2.9 0.1 0.8
(a) The soil cleanup levels are based on potential direct soil contact exposures, as calculated
using procedures set forth in WAC 173-340-740 (3)(a)(iii).
(b) Preliminary groundwater protection criteria calculated as 100 times the MTCA groundwater
cleanup level, following WAC 173-340-740(3)(ii)(A). Groundwater protection will be addressed
at this site by monitoring both the Perched Groundwater Zone and Shallow Aquifer.
These compliance monitoring data will be evaluated at the first five-year review (see text).
(c) Based on data collected from newer wells installed in the Perched Groundwater
Zone. Some of the older wells installed previously in this area may lack competent
surface seals and may not be representative of groundwater conditions.
(d) MTCA cleanup levels for total phthalates are based on bis(2-ethylhexyl)phthalate, which
is the most toxic of the phthalates detected at Site A.
283ara....u
"'d
III
oq
(I)
\..J
0\
Total Total
Lead Phthalates (d) PCBs
<10-80 <1-3 <0.1
10-2,400 <1-2 <0.1-4.1
<10 <1 <0.1
250 140 4.3
1.5 0.4 0.001
<10 <1-2 <1
<10 <1-78 <1
<10-19 <1-25 <1
3 <0.01
<5-16 <1-27 <1
<5-23 <1-40
-------
" i
~ I
Table 2 - Selection of Exposure Pathways for Quantitative Exposure Assessment
"--
~tar
0........
e....... ,
. i
........, .......
......-
e--..... .....-. - e- Paille
SU8ASE .... WIllI-. o.-..c:.:..- - ~ ill SoiI8 V.
...", I4ImI ..... 0..-.. WIIrII.....-.
~ WIaIIIAN8
MIl 01148 ~ ...,.....~.. SoiI8 v-
A..-........... AN8t ~ o.-~(D8IIo8)CGIo-
............. ~~. a... v-
.... 0.- WIIrII--
~.0I80NcIII8c:..-. v- v-
.... 0..-.. WIIrII--
('1 ......... c.--8U8ASEwa. ...
~~"A~
011III8I c... ... V80ar""'" 01 NIl
~..o.-~--
D8nIIII c:.:..- MIl V80ar ....... 01 NIl
~ 1ft CIIII8I LM8
......... ..!Iaa.r ...... ~ . FIeII No
- -- - CIIII8IL--. CM8I
0.... c:o......... I . o.naa. ...... No
c..~""~hO
""""'.~.' . ~........ ND
-""""'~__A
.......... ..-aaa-. r~.- ND
... WIdII8 0IIcIIIM0I- .. A
~ A88Id88n8 o....eao.-_~ ift VIIoI8M v-
0.....................
~""".~.s.ca.-a v-
,...,.. ..... (08nMOc.n.
........ 01 a-.Ia8III ~ III a... '188
T~ oa-.\IIIII8Id
......... 01 a-.Ia8III ~. v- v-
T~ oa-.\/IIIIMcI
CM-....4a- .01-4- - ~-- v-
---~._A
a...~-u..01~ er.... ND
~-aa-.
o....c.-_v_--. No
~..~c.-
.......... "'-. -- ~ 1ft 1"'... ND
- ....... -.... CM8I
0.... CGIo~... . .~ift.... No
c..a..-...... ~
.......... Aoaot-od- ~ .. Fouta No
... v..-
. """"'.~d~~""" ND
--
,-"
.... ...~..e-
CIIeooIic8I8. ~ eo.-.. - o..c.. 1ft SwIIcI8
SaIl ill ..... ........., U8ed ... SU8ASE 0.--
CIIeoNI8I8. ~ eo.-.. - o..c.. 1ft"'"
SoiI8 1ft..... ........., U88II ... SU8A8E c.r-
".... 0... ~ a-.. -- Sail....,...
.......... - IIIIWMIIr 0.- ~
8M' . .....~ o..c.. 1ft 0.-......
SIIIII...., ""- - ... ....... IIr 0.-......
M "-t ... AIt- " . Fv-. SU8A8E.........
.. 08rwet8 ............. ,.. ~~....~ of.. lit
0Iwi88 sure- ...... - tal. 1 -. "..........
V80ar"'-- - -ean..- - 8IIiiI"-
CIIIIIi LaD CIIenoic8I C-...... - - 0II0IIdI0t
-- -- -0enNI.--.- "'-III...
~ 1.In4...1~ . .. f1IM: CIIII8I LaD.
....., U8ed lor ~ .. OIlIer CGIo_AcIioiIi8t;
0.- 0I8II0a8 - ~ - .1.lI1
NDa-... "-tI8I C-.... - 0.- 1ft
Raft.. -- ...... --
NDa-.. 01 "-"loll ean-a .... - 0II8c:I8d III
.....c..~~.
NIl..................... -- o-w iII- "'-
WId FNI e-III e.................
-e-. ~.... H8OG8I* ~..-
.......... . T- Ca8IIIaI8at8 (T.... ... .... t8II)
0. a..... 01 '"-'dale-. -0.- 1ft ~
0--.-......
ClleOlMliatlol........ e-. - c.- 1ft ~
0- sa-.........
....... 0... CaIII8iIIiIoo ~ -- 0.- SoiI8 ....,
.............. T'-'8d, ... ........ IIr 'I11II8I8 ........
"..1 ~ c-.ia8I8 o..c.. . 0..- ........ Sc8o....,
.............. T..---. .... ........ IIr 1Il1II8IIO ......
a-.. . PalM.... c:c.-.. - 0.-. ..... A8I8.-
- - A; ~ A88oII8na u.. -- tar -......,
'IIIIIIMII c.- -.- F"'- - s.-.c ""..4..---
~c...WM8p_...a.-_~
...... c.- sa- F"'- - s.-I8I; o-w e--
e.-...... ~~ willi IM&.8MIIe8.....,
NDa-... PaI8ftII8I eo.-.. "- - ~.
Fiala .. SlMllllallIoI8dI8; - ...
No CIIMooca8 of Peo.88I c- "- - 088d8d III
..... CM8I .-- s.a-.
WId ~ e-. - ......... a.a... ',r e-
e-.... --.-c:.an.o- - -u.aoe P-.,
- e-. e-.o.... NooIiO- ~......
- of T,....... ~ (T,- -.... ,..,
-------
Table 3 - Summary of Site A Exposure Factors
Page lof2
Average RME
Exposure Factor Units CcmditiOl1 Coadition(a)
I. Dermal Absorption
a) Surface Area:
0 to 6 years m2 0.12 0.12 (b)
6 to 18 years m2 0.25 0.25 (b)
18 to 75 years m2 0.30 0.30 (b)
b) Soil Adherence Factor mg/cm2 0.60 0.90
c) Absorption:
Metals bywt. 0.1" 1.0"
Ordnance bywt. 40" 80"
PCBs/phthalates by wt. 4% (c) 10" (c)
d.) Frequency:
0 to 6 years percent 96% . 96% (b)
6 to 18 years percent 14% 96%
18 to 75 years:
SUBASE Worker percent 24% 68%
Vinland Resident percent 7% 96%
e) Duration: \
SUBASE Worker years 10 25
Vinland Resident years 9 30 (d.)
f) Body Weight:
0 to 6 years kg 15 15 (b)
6 to 18 years kg 43 43 (b)
18 to 75 years kg 70 70 (b)
ll. Soil Ingestion:
a) Ingestion Route:
0 to 6 years gmlday 0.2 0.2 (b)
6 to 18 years gmlday 0.1 0.1 (b)
18 to 75 years:
SUBASE Worker gmIciay 0.05 0.05 (b)
Vinland Resident gmlday 0.10 0.10 (b)
b) Absorption:
Metals bywt. 10% (c) 100%
Ordnance bywt. 100% 100%
PCBs/phthalates bywt. SO% (c) 100%
c) Frequency:
0 to 6 years percent 96" 96% (b)
6 to 18 years percent 14" 96%
18 to 75 years:
SUBASE Worker percent 24% 68%
Vinland Resident percent 7% 96%
d.) Duration:
SUBASE Worker years 10 25
Vinland Resident years 9 30 (d)
~ , \'~ '"
-------
J I I I
" I .
Table 3 - (Continued)
Page 20f2
Average RME
E~wo Factor UDitll Coadition Coaditioa(a)
e) Body Weight:
0 to 6 years kg 15 15 (b)
6 to 18 years kg 43 43 (b)
18 to 75 years kg 70 70 (b)
m. Dust and Vapor Inhalation:
a) Ventilation Rate:
18 to 75 years mJ/day 20 20 (b)
b) Absorption:
Dust bywt. 40% (c) 100%
Vapors bywt. 100% 100%
c) Frequency:
SUBASE Bangor Worker percent 24% 68%
Vinland Resident percent 96% 96% (b)
d) Duration:
SUBASE Worker years 10 2S
ViDland Resident years 9 30
e) Body Weight:
18 to 7S years kg 70 70 (b)
IV. Drinking Water:
a) Consumption Rate:
18 to 75 years liters/day 1.4 2.0
b) Absorption by wt. 100% 100%
c) Frequency:
Vinland Resident br/day 96% 96% (b)
d) Duration:
Vinland Resident years 9 30
e) Body Weight:
18 to 7S years kg 70 70 (b)
NOTES:
a) Exposure factors used to compute the reasonable maximum exposure (RME) scenario were based on
EPA guidelines. Average conditions were utilized in a subsequent
assessment of uncertainty.
b) Based OD EPA guideline the average and RME values for these exposure
factors are equivalenL
c) These exposure factors deviate from EPA Region 10 Guidelines,
but are consistent with the scientific literature specific to
these chemicals.
d) Including exposure during ages 0 to 6 years, with the remaiDing 24 years evaluated under adult
exposure conditions.
2830T3
-------
Table 4. Summary of Site A Burn Area Baseline R/sk Assessment; Reasonable Max/mum Exposure Scenar/o
Exposure Concentration (a) Chronic Dally Intake In mglkg-day Reference Dose In Cancer Potency In
mglkg-day (mglkg-day)-1 Ufellme
Soli Air Water Direct Air Drinking Hazard Cancer
Chemical of Potenllal Concern (mglkg) (ug/m3) (ugIL) Contact Inhalallon Water Oral fnha!. Oral Inha!. Quollent Risk
METALS:
Bar/um (and compounds) - - - - - - 7E-02 (b) 1 E-04 (c) - - - -
Cadmium (and compounds) 3E+OO U 3E-06 U 1E+00 U 2E-07 1E-10 1E-OS 5E-04 (b) 5E-04 (e) - 6E+00 (b) 0.01 7E-10
Chromium (and compounds) 3E+01 4E-OS 3E+00 U 1E-05 2E-08 4E-OS 5E-03 (b) 6E-07 (c) - 4E+01 (b) 0.04 5E-07
Copper (and compounds) 3E+01 3E-05 8E+00 1E-OS 1E-08 1E-04 4E-02 (c) 1E-02 (c) - - <0.01 -
lead (and compounds) 5E+01 5E-05 1 E+01 2E-05 2E-08 2E-04 1E-03 (c) 4E-04 (c) - - 0.10 -
Nickel (and compounds) 4E+01 5E-05 5E+00 U 1 E-05 2E-08 7E-05 2E-02 (b) 2E-02 (e) - 8E-01 (b) <0.01 1E-08
Zinc (and compounds) 1E+02 1E-04 3E+00 B 4E-05 5E-08 4E-OS 2E-01 (c) 1 E-02 (c) - - <0.01 -
ORDNANCE COMPOUNDS:
2,4,6- Trinitrotoluene (2,4,6- TNT) 6E+02 6E-04 6E-01 U 2E-03 5E-OS 8E-06 5E-04 (b) 5E-04 (e) 3E-02 (b) 3E-02 (e) 4.00 4E-OS
2,4-Dlnltrotoluene (2,4-DNT) 1E+01 8E-06 5E-02 U 3E-05 3E-07 7E-07 - - 7E-01 (b) 7E-01 (e) - 2E-OS
2,6-Dlnltrotoluene (2,6-DNT) 6E+OO 1E-06 5E-02 U 2E-05 7E-07 7E-07 - - 7E-01 (b) 7E-01 (e) - 1E-OS
1,3,5- Tr/nltrobenzene (1,3,5- TNB) 2E-01 U 2E-06 U 4E-01 U 5E-07 2E-08 6E-06 5E-OS (b) 5E-05 (e) - - 0.10 -
1,3-Dlnltrobenzene (1,3-DNB) 1E-01 8E-08 5E-01 U 3E-07 1E-07 7E-06 1E-04 (b) 1 E-04 (e) - - 0.08 -
Nitrobenzene (NB) 6E-02 1E-08 4E-01 U 2E-07 7E-07 6E-06 5E-04 (b) 5E-04 (b) - - 0.01 -
Hexahydro-1,3,5---- (RDX) 1 E+01 2E-06 2E+02 J 5E-OS 4E-06 3E-03 3E-03 (b) 3E-03 (e) 1E-01 (b) 1E-01 (e) 0.90 2E-04
2,4,6-Tr/nltropheno/ (Picric Acid) 9E-02 1E-07 5E-01 U 3E-07 6E-11 7E-06 4E-02 (c) 4E-02 (e) - - <0.01 -
2-Amlno-4,6---- (Plcramlc Acid) 1E+OO 1E-06 3E+00 U 4E-06 5E-10 4E-OS 3E-02 (c) 3E-02 (e) - - <0.01 -
1,2-Propanedlol----(Otto Fuel) 5E-02 J 6E-09 J 1 E-01 U 1E-07 5E-11 1 E-06 6E-04 (d) 6E-04 (d) - - <0.01 -
N-Methyl-N-2,4,6---- (Tetryl) 8E-02 9E-08 3E-01 U 2E-07 7E-11 4E-06 2E-03 (d) 2E-03 (d) - - <0.01 -
BASE-NEUTRAL EXTRACTABLES:
Bls(2-ethylhexyl)phthalate 2E+OO U 4E-06 U 3E+01 B 4E-06 3E-09 4E-04 2E-02 (b) 2E-02 (e) 1 E-02 (b) 1E-02 (e) <0.02 4E-06
Butylbenzylphthalate 1E-01 U 5E-07 U 1 E+oo U 2E-07 3E-09 1 E-OS 2E-01 (b) 2E-01 (e) - - <0.01 -
DI-n-buty/ phthalate 1E+OO 1E-06 1 E+OO U 1E-07 2E-08 1 E-06 1E-01 (b) 1E-01 (e) - - <0.01 -
DI-n-octyl phthalate 1E-01 U 5E-07 U 1 E+OO U 2E-07 3E-09 1 E-OS 1 E-01 (c) 1E-01 (e) - - <0.01 -
Total PCBs 4E-02 9E-08 OE+OO U 6E-08 1E-08 OE+OO - - 8E+OO (b) 8E+OO (e) - 4E-07
5.00 3E-04
NOTES:
a. Soil, air, and water concentrallons computed as the upper 95% confidence limit. Non-detects equal to one-half the detecllon 11m II.
'" b. Verified reference dose or cancer potency slope, as documented In EPA-IRIS (March 1991 access/on).
: c. Reference dose or cancer potency slope, as documented In EPA-HEAST (1990 accession) or EPA-SPHEM (1986).
(1) d. Reference dose determined by the U.S. Army Medical Bioengineering Research and Development laboratory (1981).
~ e. The oral value was assumed to be adequate to address Inhalation exposures.
-'
283OT4.wkl
.,
-------
','
~
~.. l
.
Generalized Regional Map
o
z
::>
o
en
°.0 .
Sinclair Inlet
I-
\JJ
o
::>
0..
WASHNGTON
Note: Base mao preoared from "Pugs! SOU'Id CCUltry WaShington"
~lisned Dy Kroll Map Company, II1dated.
o
4
8
Scale in Miles
..
..
HIJRTCROfNSER
.1-1463-09 11/91
-------
....
,
- .
11 ~ }
'F
Site A
Vicinity Map
t1
..y
o
o
~
-------
j I I '~
-) I ."
Site A Historical Features
--
-
~ =-=====
~ :::::::---
;:::..--: - ~
-
150
160
-AA
/
/
r
Barr I
1970 1
",----=.:::;.=.~...... ~
.:0 .,,,. .....---
«S
o
a:
«S
IIJ
o
c
i=
r--
'----- '
__~~2 Vegetation Removal
. ~ "'::::,~60 ~,
'-- ... -- "'-....
~...........,
Bum Mounds "
Established (1962) "
---
Note: Compiled from aerial photographs (1965, 1970.
1972-74. 1976-77. 1979. 1986) and historical sources.
o
150
300
Scale in Feet
( 1962)
1970
Historical Source
Observed on Available Aerial Photos
N
--
(}-1970 Approximate Removal Date of Burn Mound
..
..
J-1463-o6
Figure 3
-------
Surficial Soil TNT Concentration Contour Map
Site A Burn Ares
: I \ . .
! ''''--'------p~t;do..::~ia~'~~~~~~'i~~'~~'~'~::::~'r''~ ;;::'~:'~~:;::'~i:.~,::,,~~~,~"-;;.~::!.~,~~,~,~~~:::,~~:-
, /---------"----"-_.::.-_..::.--.----------------~. ." , '- ".--- -- ......~
I ( . 0 0 O. ---~ :-~10-f--------- -------
I I ."".
r I . . ~ ......:"'. ,
" .. 0 .'
I I . . 10 . \
I I 0 I
I I o. 0 I
I I I
'"0 I . I
,'~I .
0'
: a:'
, ~I
, 3'
, c'
"-1
I""::,
, ,
I I
I I
I /
I I
I I
I I
I '
I I
I I
I I
I I
I /
, I
, I
I I
I I
I I
: I !
,"",
(...,
',...'
. ,--
1..,'
.
.
.
.
,,"
:,/..
"""""'"""""""",!""""",,,,,,""',"'",......,..-,.............:".................../""
.
.
"'j ~~
cr
~ ~
CD 0)
.,(4
6
CD
....
....
" .
-<0
....
)
.
Sample Data Point
N--
() Previous Burn Mound Removed
o Burn Mound
)
o 100 200
,
Scale in Feet
'-"
~
.'#
) ~
,. ""
- Surficial Soil TNT Concentration Contour in ppm
-
TNT Concentration Greater than 1E -06 Risk-based
-------
"c-.
-. I
CQ ...... .
~ ~
Cb ~
<18(.)
6
co
Conceptualized Flow Model of Perched Groundwater Zone
......
......
"-
co
......
~~
I .
Sile A Burn Area
-I
) '~t~
Precipilatio~ .(
I . '
.. f.. '.'
I' :: . ; I :::; i
(rr' ,
Evapotranspiration
<~
Perched Groundwater Zone
(Seasonal, not a Drinking Water Source)
'iJ
Ground Surf ace
~
~
"
"
...' ~ . -- .
-'
Spring/Seep
....;r ~
r.i
,',: "'.
--------
---------
TIll
'Q
Shallow Aquifer
~ i
,"
..
-------
-'.
o r,
..
..
IILIIPqlOWSER
J. Ii 11/91
-#
~\-
-------
.s ;;....
,I
0,
r
"
:'~,
It
, ~
.~ ~.
Baseline Exposure Pathways
Hypothetical Conditions
Prevailing Wind Direction
Exposure Point
(Inhalation and Creek
Sediment Direct Contact
EJq:)osure Routesl
Exgosure Point
(Inhalation and Direct
Contact Exposure Routea)
~--...-...----_.
" VlNLAND CREEK
Source (Bum Mounds)
Re1e8se Mechanism
(Perched Groundwater
Leaching)
Transt:lC)tt Medium
(Groundwater)
Release Mechanism
(Creek Leaching)
.-/
'-
Groundwater Flow Direction
.
Shallow Aquifer
Sea Level AQuifer
NOT TO SCALE
..
..
HIJRTCROWSER
J-1463-o9 11/91
-------
---- - --- - __0 -- --------------
- - , _0 . .-
Site A
Conceptual .Well Layout,
Groundwater Extraction and Reintroduction
......~
............................
" " "~Extractlon "
Well (Typ.)
,j' Injection Well
. (Typ.) .
160
"
o
"
"
:TIf...
cQ'~
c:~
Q1~
Q)g
Existing Fence
~I
o
I
100
200
I
-N-,.-
Scale In Feet
ill
Existing 12-lnch Drain
-----
~
-~
-
,..
------- |