United States
Environmental Protection
Agency
Off ice of
Emergency and
Remedial Response
EPA/ROD/R10-91/033
September 1991
&EPA
Superfund
Record of
Bangor Naval Submarine
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50272-101
REPORT DOCUMENTATION 11. REPORTNO. 1 ~ 3. A8cIpi8nI'I A-.Ion No.
PAGE EPA/ROD/R10-91/033
4. 1118 8IId SWtII8 5. Report D8t8
SUPERFUND RECORD OF DECISION . 09/19/91
Bangor Naval Submarine Base, WA I.
First Remedial Action
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11. ~C) or Or8nt(G) No.
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U.S. Environmental Protection Agency 800/000
401 M Street, S.W.
Washington, D.C. 20460 14.
15. SUpplementary No...
11. Ab81r8ct (UmIt: 200 _Ida)
The Bangor Naval Submarine Base (SUBASE) is a former munitions handling, storage,
and processing facility in Kitsap County, Washington. Land surrounding the SUBASE
is generally undeveloped and supports limited residential use. The site overlies
the surficial Shallow Aquifer and deeper aquifers, which are the principal water
supplies for SUBASE Bangor and surrounding communities. Demilitarizing (demil)
operations were conducted from 1940 until 1978, and included collecting condensate
and solid explosive within a holding tank, followed by removal of the solid material
from the wastewater before final discharge. Site F, a wastewater lagoon, was used
between 1960 and 1971 for the disposal of final wastewater solution. Periodically,
the lagoon was allowed to drain. Waste materials present in surficial sediment of
the lagoon were burned off in place with waste oils, or transported to the onsite
ordnance burning area for thermal destruction. Between 1972 and 1980, wastewater
was collected into 55-gallon barrels and delivered to the SUBASE liquid-waste
incinerator. Several onsite investigations of the distribution and transport of
waste constituents at Site F have occurred since 1971. Based on data collected, it
was confirmed that soil in the lagoon area is contaminated by ordnance constituents.
(See Attached Page)
17. ~t An8Iy8Ia .. D88crIpeora
Record of Decision - Bangor Naval Submarine Base, WA
First Remedial Action
Contaminated Medium: gw
Key Contaminants: organics (RDX, 2,4,6-TNT, 2,4-DNT, 2,6-DNT, 1,3,5-TNB, 1,3,-DNB,
b. Id8ntlll8r8/Op8n-End8d Tenna N-nitrate, nitrobenzene)
c. COSA 11 R8Id.'Gr
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EPA/ROD/R10-91/033
Bangor Naval Submarine Base, WA
First Remedial Action
Abstract (Continued)
In 1972, 500 cubic feet of soil was excavated from the top several feet of the lagoon
and transported to the onsite ordnance burning area for burning. In 1980, the lagoon
was filled in and covered with a low permeability asphalt cover. Ground water quality
data collected at Site F during prior studies indicated that only the Shallow Aquifer
has been impacted by Site F. This Record of Decision (ROD) is an interim remedial
action addressing ground water contamination at Site F as Operable Unit 2 (OU2). The
intent of this Remedy is to contain the contaminated ground water plume. A future ROD
will address final remediation of both soil and ground water. The primary contaminants
of concern affecting the ground water are organics including RDXi 2,4,6-TNTi 2,4-DNTi
2,6-DNTi 1,3,5-TNBi 1,3-DNBi N-nitratei and nitrobenzene.
The selected remedial action for this site includes pumping and treatment of ground
water from the Shallow Aquifer using UV-oxidationi reinjecting the treated ground water
onsite into the Shallow Aquifer, or infiltrating it onsite using a recharge basini
ground water monitoringi and providing design information, as applicable, for the final
remedy. If the UV-oxidation process cannot achieve the specified performance standards
due to either technological or economic concerns, then carbon adsorption will be
coupled with the UV-oxidation system to complete the treatment process prior to
disposal. The estimated present worth cost for this remedial action is $2,515,000,
which includes an O&M cost of $1,300,000 over 2 years.
PERFORMANCE STANDARDS OR GOALS: Chemical-specific ground water clean-up goals are
based on MTCA clean-up standards and include RDX 5 ug/l, 2,4,6-TNT 3 ug/l,
2,4-DNT 0.1 ug/l, 2,6-DNT 0.1 ug/l, 1,3,S-TNB 0.8 ug/l, 1,3-DNB 2 ug/l,
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Declaration of the Record of Decision,
Decision Summary, Responsiveness Summary,
and Administrative Record Index
for
Interim Remedial Action
Naval Submarine Base Bangor Site F
. ~
(Operable Unit 2) ~
Bangor, Washington
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DEClARATION OF
THE RECORD OF DECISION
SITE NAME AND LOCATION
Naval Submarine Base Bangor Site F (Operable Unit 2)
Bangor, Washington.
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected interim remedial action for Site F (Operable
Unit 2) at the Naval Submarine Base, Bangor in Bangor, Washington, developed in
accordance with the Comprehensive Environmental Response, Compensation, and Liability
Act, as amended by the Superfund Amendments and Reauthorization Act, and, to the
extent possible, the National Oil and Hazardous Substances Pollution Contingency Plan.
This decision is based on the contents of the administrative record for the site.
The lead agency for this decision is the U.S. Navy. The U.S. Environmental Protection
Agency (EPA) 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 interim remedial action alternatives. The State of Washington
concurs with the selected remedy.
ASSESSMENT OF THE SITE
This interim remedial action will provide an opportunity to significantly reduce the mobility
of the groundwater contamination, thereby reducing the potential risk. to human health and
the environment. 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. It will also implement a cleanup strategy expected to be consistent
with the final remediation and minimize additional remediation costs which would
otherwise occur if no action were taken at this time.
DESCRIPTION OF SELEcrED REMEDY
The selected remedy for interim remedial action for Site F at the Naval Submarine Base
addresses the threat posed by the site by providing groundwater containment and on-site
treatment with permanent reduction in the mobility, toxicity, and volume of contamination.
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The elements of the preferred interim remedial action alternative include:
~ Extract groundwater from the Sha1l9w Aquifer using extraction wells to contain the
contamination and thereby confine funher contaminant movement in the aquifer;
~ Treat the extracted groundwater using an Ultraviolet/Oxidation process to meet
applicable federal and state regulations prior to disposal;
. Dispose of the treated groundwater on-base by recharge or injection into the Shallow
Aquifer; and
. Monitor the effectiveness of the groundwater containment and groundwater treatment
process throughout the interim action.
DECLARATION
This interim action is protective of human health and the environment, complies with
Federal and State applicable or relevant and appropriate requirements for this limited-
scope action, and is cost-effective. Although this interim action is not intended to fully
address the statutory mandate for permanence and treatment to the maximum extent
practicable, this interim action does utilize treatment and thus is in furtherance of that
statutory mandate. Because this action does not constitute the final remedy for the
operable unit, the statutory preference for remedies that employ treatment that reduces
toxicity, mobility, or volume as a principal element, although partially addressed in this
remedy, will be addressed by the final response action. Subsequent actions are planned to
address fully the threats posed by the conditions at this operable unit.
Because this remedy will result in hazardous substances remaining on site above health-
based levels, a review will be conducted to ensure that the remedy continues to provide
adequate protection of human health and the environment within five years after
commencement of the remedial action. Because this is an interim action Record of
Decision, review of this operable unit and of this remedy will be ongoing as the Navy
~~~~~O~~:/19/ .
SUBASE, Bangor Commanding Officer
United States Navy
~ft- ~
Dana A. Rasmussen
Regional Administrator, RegionJ.O
United States Environmental Protection Agency
~11,1~1
Date
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Signature sheet for the foregoing SUBASE, Bangor - Site F, Interim Remedial Action,
Record of Decision betWeen the United States Navy and the United States Environmental
Protection Agency, with concurrence by the Washington State Depanment of Ecology.
-C~~. J~
Carol Fleskes, Program Manager
Toxies Oean-up Program
Washington State Depanmem of Ecology
1/.;20/9/
Date
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CONTENTs
DECLARATION OF THE RECORD OF DECISION
Pa"e
DECISION SUMMARy
1.0 lNTRODUcnON
1
2.0 SITE NAME, LOCATION, AND DESCR1PTION
3.0 SITE HISTORY AND ENFORCEMENT AcnONS
1
1
4.0 COMMUNrry RELATIONS
2
5.0 SCOPE AND ROLE OF OPERABLE UNITs
4
6.0 SUMMARY OF SITE CHARAcrmurncs
5
6.1 Site Hydrogeologic ConditWns
6.2 Site Waste ConstUuenJs
6
7.0 SUMMARY OF SITE RISKS
6
9
8.0 DESCRIPTION OF ALTERNATIVES
11
8.1 AlJeTTlDiive 1: No Action
8.2 AlJeTTlDiive 2: Conltuni1uznt Migration ConJainmenlby GroundwaJer
Extraction and Treatment by Ultraviolet/Oxidation
8.3 Allenumve 3: Conltuni1uznt Migration ConJainmen.t by GroundwaJer
Extraction and Treatment by Carbon Adsorption
8.4 AlJe17UlJive 4: UpgrrulWu Subszuface Bil17"U1r to Divert
RegioIUll Groundwater Flow around the Cont4mUuzdon
12
12
12
14
14
9.0 COMPARATIVE ANALYSIS OF ALTERNATIVES
14
9.1 Protection 01 HU11Uln Health and the Environment
9.2 ConrplUmce with ARARs
14 .
15
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CONTENTS (Continued)
Page
9.3 Reduction o[ ToxiciJy, Mobility, or Volume by Treatment
9.4 Short- Term Effectiveness
9.5 Long-Term Effectiveness and Permanence
9.6 Implementability
9.7 Cost
9.8 StIJU Acceptance
9.9 Community Acceptance
16
16
17
17
18
18
18
10.0 THE SELECTED REMEDY
19
10.1 Feasibility o[ Groundwater Extraction
10.2 Containment Level o[ RDX in Groundwater
10.3 Effectiveness o[ Treatment Technology
10.4 Disposal o[ Treated Groundwater
19
21
22
22
11.0 STATUTORY DETERMINATION
23
11J Protection of Human Heal1h and the Environment
11.2 ComplUuu:e with Applicable or Relevant and ApproprUue
Requimnents
11.3 Cost-Effectiveness
11.4 Utilization of Pemuuu!nt Solutions and AltenuzJive Treatment
Technologia or Resource Recovery Technologies to the Maximum
Extent Practi~able
11.5 Preference for Treatment as Principal Element
24
24
26
26
26
u.o DOCUMENTATION OF SIGNIFICANT CHANGES
27
TABLES
1 Comparison of Maximum Concenttations of Chemicals
Detected at Site F with EP A-Superfund Threshold Levels
for Remedial Action
2 Summary of Water Treatment Objectives - ARARs - for Bangor
Site F Proposed Interim Action
3- Cost Estimate for Alternative 2: Groundwater Extraction and
Treatment by UV 1000dation
28
29
30
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CONTENTS (Continued)
4 Cost Estimate for Alternative 3: Groundwater Extraction and
Treatment by Carbon Adsorption
5 Cost Estimate for Alternative 4: Slurry Wall
FIGURES
1 Generalized Regional Map
2 Site F Historical Features Map
3 Well Location Plan
4 Generalized Subsurface Cross Section A-A'
5 Shallow Aquifer Water Table Elevation Contour Map - January 1991
6 RDX and TNT Concentration Contour Map
7 RDX Concentration Contour Map and Estimated Groundwater Capture Zone
ATl'ACHMENT A
RESPONSIVENESS SUMl\{ARy
OVERVIEW
SUMMARY OF PUBUC COMMENTS
RESPONSE TO COMMENTS
1. Publi& Involvement
2. &lDJionship 01 Interim &medUd Action to FUUJl &medy
3. lssws &liIted to Groundwater Contllmintllion at SiU F
4. Effect 01 Groundwater Extraction on Water Supplies
S. Monitoring 01 GlT1lI1Idwater Contllmintllion
6. Disposal 01 Treated Groundwater
7. Effectiveness olIM Proposed Treatment Technology
ATl'ACHMENT B
ADMINISTRATIVE RECORD INDEX
~
31
32
A-1
A-1
A-1
A-3
A-3
A-4
A-4
A-6
A-7
A-8
A-9
B-1
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DECISION SUMMARY
1.0 INTRODUcnON
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 Site F at Naval Submarine Base Bangor, the selected interim
remedial action will comply with applicable or relevant and appropriate requirements
(MARs) promulgated by the Washington State Department of Ecology (Ecology) and the
U.S. Environmental Protection Agency (EPA).
This interim action is proposed to minimize the further spread of contamination during the
completion period of the detailed remedial investigation and feasibility study (RIfFS). The
RIIFS is necessary to determine the full nature and. extent of on-site soil and groundwater
contamination.
2.0 SITE NAME, LOCATION, AND DESCRIPTION
U.S. Naval Submarine Base (SUBASE) Bangor is located in Kitsap County, Washington,
on Hood Canal approximately 10 miles north of Bremerton. Site F is located in the
south-central portion of SUBASE Bangor, approximately 1.5 miles east of Hood Canal
(Figure 1). Land surrounding SUBASE Bangor is generally undeveloped or supports
limited residential use within the communities of Vinland (to the north), Olympic View
and Bangor (to the west), and Silverdale (to the south).
Site F (defined as the former wastewater disposal lagoon) is located west of the SUBASE
. Segregation Facilities in a clearing surrounded by a large forested area. The site occurs in
a generally closed basin which receives surface water inflow from adjacent drainages but
no surface water drainage leaves the area. The ground elevation near the disposal lagoon
is approximately 300 to 310 feet mean sea level (MSL) and increases to the west until it
reaches a plateau ranging in elevation from 375 to 400 feet MSL The former wastewater
disposal site consisted of a 300-square-foot unlined evaporation lagoon and overflow area
located adjacent to the Segregation Facility. Local features include a Naval Heli-pad
located approximately 700 feet northwest of the site and barricaded sidings and rail line
approximately 1,500 feet west. The only access road into the site is via the Segregation
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. .
3.0 SITE mSTORY AND ENFORCEMENT ACTIONS
The concern over the environmental impact of ordnance operations at SUBASE Bangor
originated from activities prior to its commissioning as a submarine base. From the early
19405 until 1971, the Bangor Naval complex served as a munitions handling, storage, and
processing site. Limited demilitarization (denri1) operations continued on a limited basis
until about 1978. Site F, which represents a former wastewater lagoon and overflow area,
was used between approximately 1960 and 1970 for the disposal of wastewater produced
during the demilitarization of ordnance items in the adjacent Segregation Facility building.
The Segregation Facility consisted of three primary segregation plants and several other
smaller buildings. Figure 2 shows the historical features at the site including the location
of the former wastewater lagoon and overflow channel.
Between approximately 1957 and 1978, the segregation facility's primary functions included
the demil of Mk 6 and Mk 25 rocket warheads, Mk 6, Mk 8, and Mk 9 mines and depth
charges, and 5-inch projectiles. These ordnance items contained primarily trinitrotoluene
(TNT), Composition A, Composition B, and Amatol. Residues of TNT, hexahydro-1,3,5-
trinitro-1,3,5-triazine (RDX), and picric acid were identified within the building prior to its
decontamination in 1980-81. Demiling activities reached a peak during 1966 to 1970 as a
result of the Vietnam conflict.
The procedures used for the demiling of ordnance items included preliminary cutting or
boring of large items using a mechanical tool, followed by steam cleaning; other items
were demiled entirely through a steam melt-out process. During the steam-out process,
steam was directed into the ordnance, and the resulting condensate and solid explosive
were collected within a holding tank. Discharge from the holding tank was then directed
into slcimmiTtg and settling chambers, which removed much of the solid materials from the
wastewater before final discharge.
Prior to 1972, the final wastewater solution was discharged through a drain line directly
into the former wastewater lagoon. Beginning in 1972-73, wastewater was collected into
55-gallon barrels and delivered to the SUBASE, Bangor liquid-waste incinerator.
The quantity of ordnance demiled within the Segregation Facility is not well documented.
Estimates range from as low as 500 pounds to up to 500,000 pounds, although a value well
toward the lower estimate seems most plausible based on disposal records and interviews
conducted with former workers.
Reponedly, ordnance recovered within the Demil Facility was flaked, boxed, and sent to
magazines for future disposition. Some of these materials were apparently sold back to
manufacturers such as DuPont, Atlas Powder, and Pacific Powder. The quantity of this
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"recycled" ordnance is not well documented. Ordnance not recycled was taken either to an
ordnance burning area (Site A) located to the north on SUBASE, Bangor or off base for
thermal destruction (such as Yakima, Washington, and Hawthorne, Nevada).
I'
r-
. .
As stated above, during the period from 1960 to 1971, wastewater from the DemiI Facility
was directed to an infiltration and evaporation lagoon and overflow area. Periodically, the
lagoon was allowed to drain. Waste materials present in surficial sediments of the lagoon
were reportedly ''burned-off'' in place with waste oil during the 19605, or transported to
Site A for burning and disposal.
. -
r '
i
In February 1972, 500 cubic feet of soils were excavated from the top several feet of the
former lagoon area and delivered to Site A for burning. In an effort to funher reduce
potential waste constituent transport from Site F, in 1980 the former lagoon area was filled
in and covered with asphalt.
...
r-
l -
Also in 1980, demiI operations at the Bangor Segregation Facility were transferred to the
Indian Island Annex. The buildings were subsequently decontaminated and converted to
storage.
~ -
- .
A considerable number of on-site investigations of the distnbution and transport of waste
constituents at Site F have occurred since 1971. One of the conclusions reached during
the earlier studies was that at least 4,300 kg of TNT and 140 kg of RDX were present, in
1974, within soils directly below the former disposal area.
l .
l
In 1978, the Navy began an Assessment and Control of Installation Pollutants (ACIP)
program to evaluate waste disposal sites at SUBASE Bangor, including Site F. Work at
Site F continued in 1981 as part of an Initial Assessment Study (IAS) and in 1986 as part
of a Characterization Study, both under the Navy Assessment and Control of Installation
Pollutants (NACIP) program. In the latter 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. As a result, the Navy suspended funher
NACIP program activities and phased into the EP A Remedial InvestigationJFeastbility
Study (RI/FS) program.
[
t:
I
r
On July 14, 1989, the EPA proposed SUBASE Bangor, including Site F, for listing on the
National Priorities List (NPL) of Hazardous Waste Sites. On August 30, 1990, SUBASE
Bangor was officially listed on the NPL. The RIIFS investigation at Site F is currently
ongoing.
:'::'
Page 3
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4.0 COMMUNI1Y RElATIONS
The overall Navy Community Relations Plan for the NPL sites at SUBASE, Bangor is
presented in the Site F Management Plan, available for review in the information
repositories. The specific requirements for public participation pursuant to CERCU
section 117(a), as amended by SARA, include releasing the Proposed Plan to the public.
This was done in February 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 horaries:
Bangor Branch (206) 779-9724
Naval Submarine Base Bangor
Silverdale, Washington 98315-5000
Main Branch (206) 377-7601
1301 Sylvan Way .
Bremenon, Washington 98310
The Administrative Record is on file at:
Engineering Field Activity, Northwest
Naval Facilities Engineering Command
3505 N.W. Anderson Hill Road
SilverdaJe, 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 Reponer
(February 20, 1991) and the Bremenon Sun (February 18, 1991). A public comment
period was held from February 18, 1991, to March 20, 1991. A public meeting was held
on February 28, 1991, with presentations given by the Navy, EP A, and Ecology. A total of
51 people attended the public meeting.
A total of seventeen comments were received by the Navy concerning the Proposed Plan.
Twelve written comments were submitted and discussed at the public meeting. In
addition, five comment letters were submitted to the Navy during the comment period.
The public comments are summarized and responses presented in the Responsiveness
Summary (Attachment A) portion of this document.
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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 interim remedial action decision.
The community relations activities at the site include the following:
. Technical Review Committee (TRC) meetings with representatives from surrounding
communities; .
. Issuance of one fact sheet for the Site F RIIFS. Additional fact sheets will be issued to
provide updates on the work being performed and major findings at Site F and the
other operable units;
. Coordination with other citizens groups which may form in response to site
investigations of concern to the community; and
. Future public meetings to present information related to the Site F RIIFS.
5.0 SCOPE AND ROLE OF OPERABLE UNITS
Site F (Operable Unit 2) is one of seven operable units comprising 21 known and/or
suspected hazardous waste sites located at SUBASE Bangor. Site F is geographically
separate from the other operable units that comprise the Bangor NPL Site.
The Interim Remedial Action is a measure to prevent the spread of ordnance constituents,
reduce the potential risk of impact to existing and future groundwater users located
downgradient from the site, and initiate a strategy expected to be consistent with the final
remedy. This action is limited to addressing groundwater contamination, whereas the final
remedy will consider both groundwater and soil cleanup. The proposed interim action
which includes groundwater extraction to contain the contaminants in the aquifer,
groundwater treatment, and disposal will likely become a major component of the final
remediation at the site.
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6.0 SUMMARY OF SITE CHARACTERISTICS
This section presents a summary of site conditions including a discussion of the
hydrogeologic characteristics and site waste constituents. The principal exposure pathway
of concern to human health and the environment is the transpon of site contaminants in
the groundwater beneath the site. Contaminated soils do exist on site. However, the
majority of these soils are capped with asphalt, thereby reducing the potential for
exposure.
There are no critical habitat areas (including those of threatened or endangered species),
wetlands, floodplains, or historical preservation sites in the area covered or affected by the
interim action. Accordingly, there are no identified environmental concerns as defined
under the National Environmental Protection Act (NEP A), associated with the operable
unit or the area affected by the interim action at Site F.
Data being collected during the ongoing Site F Remedial Investigation will be used to
refine and update our understanding of site conditions. Nevertheless, sufficient
information is currently available to undertake this interim remedial action. Additional
da~ as available, will be incorporated into the existing database for the interim action
design. . .
6.1 Site Hydrogeologic Conditions
There are three hydrogeologic units that have significance for the Interim Remedial Action
at Site F. The units are:
~ Vashon Till (Qvt); .
~ Shallow Aquifer (Vashon Advance Outwash, which is subdivided into two members:
Ovat and ~; and
~ Vashon Proglacial Aquitard (Qvp).
Subsurface explorations at Site F and other locations on SUBASE Bangor indicate that
this vertical sequence of units is regionally consistent.
Regionally, the Sea Level Aquifer and deeper aquifers underlie the Vashon Proglacial
Aquitard. These aquifers provide the principal water supply for SUBASE Bangor and
surrounding communities. However, available data indicate that only the Shallow Aquifer
has been impacted by Site F, Le., no contaminants associated with Site F have been
detected in the Sea Level Aquifer or in deeper aquifers. These data and data from the
on-going RI/FS indicate that the Vashon Proglacial Aquitard is both continuous across the
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site area and competent enough to impede the downward migration of groundwater
through it.
Figure 3 shows the location of monitoring wells located at Site F which were used to assess
geologic conditions beneath the site (during drilling) and provide an effective monitoring
network to assess groundwater quality. The hydrogeologic units beneath Site F are
illusttated on Figure 4, which is oriented east to west (cross section location is shown on
Figure 3). Each of the three hydrogeologic units is descnbed below.
Vashon Till (Qvt). The Vashon Till consists of a dense, unsorted gravelly, silty sand. The
till forms a low permeability veneer over the site which limits the rate of infiltration to the
underlying Shallow Aquifer. The thickness of the till ranges from approximately 25 to 45
feet across the site area. In the immediate area of the former wastewater lagoon, the till
is approximately 25 feet thick.
Lenses of silt and sand also occur within the till, but they are laterally and vertically
discontinuous. Although the isolated sand lenses become seasonally saturated, they do not
constitute a perched aquifer system because of their lack of interconnection.
Shallow Aquifer (QvaJ. The Shallow Aquifer is an unconfined (water table) aquifer
occurring within a thick sequence of Vashon Advance Outwash sand, which directly
underlies the Vashon Till. Depth to water in the Shallow Aquifer ranges from
approximately 50 feet near the former wastewater lagoon to more than 150 feet in
topographically higher areas to the west. Locally, the aquifer is extensive, with a saturated
thickness ranging from 60 to 100 feet.
The advance outwash deposits comprising the aquifer become finer grained with depth,
grading from gravelly, coarse to medium sand downward into very silty, fine sand. The
lower very silty portion of the outwash (Ova,) is differentiated from the rest of the
outwash (Qva.0 because of its unique fine-grained nature. Field observations during
drilling and confirmatory grain size analyses suggest that the Ova, does not readily transmit
water, and therefore effectively forms the bottom of the Shallow Aquifer. The Shallow
Aquifer is exceptionally uniform across the area, and is highly permeable, with an average
horizontal hydraulic conductivity estimated from pumping test and slug test data on the
order of 10'2 cm/sec.
The Shallow Aquifer water table slopes gently toward the west-northwest, with a horizontal
gradient of approximately 0.003 (3 foot drop for 1,000 feet horizontally). Accordingly, the
groundwater flow is generally in a northwesterly direction, as shown on Figure 5. The
average linear groundwater flow rate is approximately 120 to 140 feet per year.
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Vertical hydraulic gradients also exist within the Shallow Aquifer, which appear to affect
constituent migration within the aquifer. Downward gradients occur near the former
lagoon area, resulting in a downward migration of waste constituents from the source area.
The vertical gradient reverses to an upward direction in the area of monitoring wells
F-MW25, F-MW18, and F-MW36, and becomes downward again at the location of
F-MW41 (see Figure 3 for well locations). The vertical gradients appear to change as the
groundwater flows up and over a ridge in the underlying silt aquitard, as discussed below
(see Figure 4).
The Shallow Aquifer receives recharge from precipitation and discharges in the direction
of flow (northwest) to on-base springs which feed trIbutaries flowing to Hood Canal, and
possibly directly to Hood Canal. There are no on-base water supply wells completed in
the Shallow Aquifer; however, such wells exist in the surrounding communities. The
nearest water supply wells located toward Hood Canal (west of the site) and screened
within the Shallow Aquifer are located off base approximately 6,000 feet west within the
community of Olympic View, and approximately 10,000 feet we~t-northwest in the Town of
Bangor.
Water quality data collected from on-site monitoring wells indicate that RDX has been
transponed in the Shallow Aquifer up to 3,000 feet to the northwest of the former
disposal lagoon. RDX is the most mobile in groundwater of the ordnance constituents
identified at the site. The extent of RDX contamination in the aquifer can be used to
define the maximum extent of ordnance contamination. Consequently, RDX is being used
as an indicator parameter to define the interim action groundwater containment boundary
since it has migrated the furthest from the former disposal lagoon.
Figure 6 shows a contour map of RDX concentrations in the Shallow Aquifer. The extent
of RDX at the 500 micrograms per liter (JlW!-) and 80 JlW!- concentrations are depicted.
This figure also shows the distnbution of TNT in the aquifer. Compared with RDX, TNT
is less mobile in groundwater and moves at a slower rate through the aquifer. The
distnoution of TNT concentrations in the groundwater indicates that it has not migrated
far from the source area. Detectable concentrations of TNT are contained within the 80
Jlg/L RDX boundary. This condition is also representative of other ordnance constituents
such as dinitrotoluenes and nitrobenzene.
Contaminated groundwater occurs principally near the water table at the source area and
moves deeper into the aquifer as it moves down gradient. No waste constituents have been
detected east of the site.
VashOD ProglaciaI Aquitard (Qvp). The Vashon Preglacial Aquitard is a thick low
permeability unit which separates the Shallow Aquifer from deeper aquifer systems in the
area. In the Site F area the aquitard is approximately 60 to 80 feet thick based on
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geologic data from existing SUBASE, Bangor monitoring wells, and consists of clayey silt
with occasional interbedded silty sand and gravel layers. The geometric mean of 7
laboratory measurements of vertical hydraulic conductivity of the aquitard material is
approximately 10-7 em/see, which is approximately 100,000 times lower than the overlying
Shallow Aquifer.
6.2 Site Waste Constituents
'6.2.1 Soils
Soil quality data were collected during well drilling activities by the USGS in 1974,
SUBASE, Bangor in' 1981, and Hart Crowser in 1990. Approximately fifty percent of the
soil samples were collected within the former wastewater lagoon area and overflow
channel, with the remainder collected from downgradient locations away from the lagoon.
No surficial soil samples were collected from the original lagoon area. However, surficial
soils of the lagoon were removed off site in 1972 and replaced with clean fill. Because of
the presence of fill materials and the asphalt cover which overlies the former lagoon,
potential direct contact with such soils is presently minimal.
The constituents analyzed in the soil samplings prior to the Hart Crowser sampling in 1990
were largely limited to TNT and RDX. All but one of the soil samples collected within
the disposal area contained detectable levels of TNT and RDX. Conversely, only two soil
samples collected outside the lagoon and overflow ditch area exhIbited detectable
ordnance concentrations. Furthermore, these two detections were from samples collected
at the water table, suggesting that the presence of the ordnance was likely due to
groundwater transport.
Based on more recent data collected by Hart Crowser, RDX and TNT are confirmed as
the primary ordnance constituents identified in soils in the disposal area. The other
ordnance constituents detected at lower concentrations in the disposal area soils include
1,3,5-trinitrobenzene (TNB), 1,3-dinitrobenzene (DNB), 2,4- and 2,6- dinitrotoluene
(DNT), nitrobenzene, picric and picramic acid, and tetryl. Low levels of various metals
were also detected in the soils.
The waste constituents disposed of at Site F were found to be transported through the soil
matrix with infiltration into the underlying water table. Termination of discharge and
capping of the disposal area in 1980 likely limited water infiltration below the lagoon and
reduced further leaching.
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6.2.2 Groundwater
Groundwater quality data have been cnllected at Site F during prior studies beginning in
1974, during development of the Current Situation Report in 198611987, and as part of the
ongoing RI/FS. Groundwater samples have been collected from approximately 35 on-site
wells completed in the Shallow Aquifer. The database includes groundwater sampling data
coneCted by the USGS, SUBASE, Bangor, and most recently Han Crowser.
The lateral and vertical distnDutions of site waste constituents within the Shallow Aquifer
are fairly well known. The ordnance waste constituents detected have included TNT,
RDX, DNT, TNB, and nitrobenzene. Nitrate and low levels of various metals and organic
chemicals were also detected. A summary of the maximum concentrations detected in
groundwater at Site F is presented in Table 1.
Based on the Tab]e 1 summary, the ordnance constituents detected at the highest
concentrations in the Shallow Aquifer were RDX and TNT. As discussed previousJy,
RDX is more mobile than TNT and the other ordnance constituents, and has migrated the
furthest downgradient from the disposal area. Basea on existing data, the bulk of the TNT
in the groundwater has not migrated far from the fanner wastewater lagoon area.
In an effort to examine the poss,Dility of existing Impacts to water supply wells completed
in the Shallow Aquifer within downgradient communities from Site F, SUBASE (in
conjunction with the IQlsap County Health District) conducted an annual monitoring
program of seleCted off-site water SUpply wells from 1984 to 1987. The sampling sites
included twelve (12) off-base domestic supplies east and west of Site F, which obtained
water from botb the Sballow and Sea Level Aquifers. Eight SUBASE Bangor water
supply wells completed within the Sea Level Aquifer or deeper aquifers have also been
monitored.
No ordnance-related constituents were detected in any of the off-site water samples
COneCted during this monitoring program.
The contaminated groundwater at Site F is not regulated under the Resource
Conservation and Recovery Act (RCRA) as a RCRA waste since this does not involve a
listed process nor does the contaminated groundwater represent a characteristic hazardous
waste.
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7.0 SUMMARY OF SITE RlSKS
Elevated levels of ordnance constituents are present in the soils around the former
wastewater lagoon and in the groundwater beneath the site. Remedial measures which
included paving the site have reduced further migration of ordnance to the groundwater
from the former lagoon. The paving also has minimized the potential health risk
associated with direct contact and potential dust emission exposures to contaminated soil.
Ordnance constituents are also present in the groundwater beneath the site and are
migrating in a northwesterly direction away from the former wastewater lagoon area. The
continued transport of ordnance in groundwater, with its associated potential for impacts
to future drinking water supplies downgradient of Site F, poses the most significant health
risk at the site. The proposed interim action is designed to reduce the potential for future
groundwater exposures to site contaminants by minimizing further migration.
A quantitative health risk assessment for Site F will be conducted as part of the RI/FS, but
has not been completed. However, a recent (1991) Superfund Directive clarifying the use
of "default" risk assessment methodologies was used as a basis for calculating the risk
threshold at this site. The risk levels derived from this directive are presented in Table 1
for individual contaminants detected at Site F, and are based on the assumption of
(future) drinking water use of the aquifer. Oeanup is generally warranted under
Superfund whenever site concentrations exceed these threshold action levels. More
stringent cleanup requirements may be determined as a result of the final RIIFS, though
these evaluations are not yet available.
The waste constituents detected in the Shallow Aquifer at concentrations above the
calculated risk levels include RDX, TNT, DNT, TNB, DNB, nitrobenzene, nitrate, and
mercury (Table 1). The highest concentrations of all of these chemicals have consistently
been observed at locations immediately adjacent to the former wastewater lagoon area.
As discussed above, concentrations of most waste constituents in the groundwater decrease
rapidly with increasing distance from the former lagoon. Recent (screening-level) results
of groundwater sampling at the site suggest that only RDX is present at detectable. levels
more than 3,000 feet from the lagoon. However, the concentration of RDX at this
distance was below the calculated risk level. Additional data is being collected to more
precisely determine the extent of RDX contamination in the Shallow Aquifer.
The degree and extent of aquifer contamination provides the basis for the interim
remedial action. The goal of the interim action is to prevent the spread of the
contamination in a manner which will be consistent with the yet to be determined final
remedy.
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The clean-up goals for the disposal of the treated groundwater which apply to those
alternatives involving groundwater extraction and treatment are, in this case, different from
the threshold action levels presented in Table 1. Treatment standards are based on
applicable or relevant and appropriate requirements (ARARs). Because this is an interim
action, chemical specific ARARs are applicable only as they relate to the disposal of the
treated groundwater.
8.0 DESCRIPTION OF ALTERNATIVES
Four alternatives were evaluated as possible interim remedial actions at Site F.
8.1 Alternative 1: No Action
Under the no action alternative, ordnance compounds present in the groundwater will
continue to migrate until a final remedy is selected, designed, and implemented. The
schedule for the Site F RIfFS, as specified in the Federal Facilities Agreement, SUBASE
Bangor, dated January 29, 1990, includes submittal of the draft RIfFS by July 1992 and the
final RIfFS by December 1992.
Evaluation of alternatives for the fmal remedy (Proposed Plan) and selection of the final
remedy (Record of Decision) is scheduled to occur by September 1993. Consequently, the
final remedy may not be implemented until late 1994 or early 1995 depending on the final
remedy selected and the time period required for design. The no action alternative will
therefore result in additional migration of the groundwater contamination and possibly
lead to a higher cost of the final remedy.
There is no time constraint associated with this alternative. The no action alternative
could be implemented immediately upon finalization and adoption of a Record of
Decision.
.8.2 Alternative 2: Contaminant Migration Containment by Groundwater
Extraction and Treatment by Ultraviolet/Oxidation
This alternative involves extracting groundwater from the contaminated aquifer, treating it
by ultraviolet light and oxidation (UV/oxidation) to meet water quality criteria necessary
for disposal, and disposal of the treated water back into the aquifer. Groundwater from
the Shallow Aquifer would be pumped from an extraction well network designed to
capture the groundwater with an RDX concentration greater than or equal to 80 ppb. A
pumping rate of 150 to 200 gallons per minute (gpm) is expected to be sufficient to
prevent further contaminant migration and thereby contain the groundwater
contamination.
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The pumped water would be treated in an above-ground ultraviolet (UV) light and
oxidation treatment system which will break apan the complex ordnance chemicals and
conven them into components such as carbon dioxide, water, and nitrate. This breakdown
is accomplished by exposing the contaminants to a combination of ultraviolet light and a
chemical oxidant such as hydrogen peroxide in a controlled chamber.
The UV/oxidation system is an innovative technology which has been used successfully in
pilot-scale and small field-scale applications to treat ordnance-contaminated wastewater.
Although relatively minor quantities of ordnance 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. The application at Site F
will require treatment of very low levels of ordnance at a relatively high flow rate. Existing
case studies were conducted at lower flow rates than those anticipated at Site F, and the
treatment criteria in these case studies were not as stringent as that required for Site F.
Because UV/oxidation is an innovative technology, additional laboratory and pilot scale
studies are necessary to tailor the technology to a particular site groundwater. Treatability
studies using UV/oxidation are currently being performed to verify that the treatment
system is effective in removing all potential constituents in Site F groundwaters. The
available information suggests that a UV/oxidation system can be designed which will
achieve the required treatment levels for groundwater disposal. No 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.
The treated groundwater will be disposed of back into Shallow Aquifer on base by
groundwater injection into wells or by infiltration using a recharge basin. The injector
wells or recharge basin would be located outside the identified zone of aquifer
contamination. The groundwater disposal will likely be located upgradient of the site to
hydraulically enhance containment, if practicable, and will not impact the effectiveness of
this interim action.
This alternative can be commenced within a IS-month period after Record of Decision
signature predicated on completion and findings of the treatability study.
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8.3 Alternative 3: Contaminant i\ligration Containment by Groundwater
Extraction and Treatment by Carbon Adsorption
This alternative includes the same procedure of groundwater extraction and disposal after
treatment as Alternative 2. However, the water treatment process is different and involves
the filtering of the contaminated groundwater through a carbon filter. This process
involves removal of the contaminants by adsorption and concentration on granular
activated carbon. Carbon treatment is a proven, conventional technology which can attain
all cleanup criteria. This alternative will generate spent carbon waste requiring transpon
and off-site disposal by incineration. Although no air emissions are anticipated under this
alternative, off-site releases can occur during final incineration and treatment of the spent
carbon.
This alternative can be commenced within a IS-month period after Record of Decision
signature.
8.4 A1lernative 4: Upgradient Subsurface Barrier to Divert
Regional Groundwater Flow around the Contamination
This alternative involves controlling further migration of ordnance compounds by installing
a barrier to diven the groundwater flow around the contaminated groundwater. A
subsurface barrier would be constructed across a portion of the Shallow Aquifer to restrict
incoming groundwater. This alternative does not include groundwater treatment, but
prevents additional groundwater from becoming contaminated.
This alternative may take longer to commence than a IS-month period after Record of
Decision signature due to an anticipated lengthy design phase.
9.0 COMPARATIVE ANALYSIS OF ALTERNATIVES
The four cleanup alternatives were evaluated based on the nine criteria established by
EP A guidelines. The no action alternative was included as a baseline comparison. The
fonowing section evaluates the alternatives by the nine applicable criteria.
9.1 Protection 01 Human Health and the Environment
Based on the preliminary findings, groundwater contamination by ordnance at Site F
appears to be restricted to the Shallow Aquifer which is not presently used for on-base
- drinking supply. However, future risks to poss1ole down gradient groundwater users may
occur if groundwater contaminants continued to migrate off site. For this reason,
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protection of human health and the environment was assessed relative to the ability of the
interim action alternative to contain contaminated groundwater.
Alternatives 2 and 3 are protective of human health and the environment. Both prevent
further migration of ordnance constituents in groundwater and are protective of future
groundwater uses. Alternative 2, however, also provides final on-site treatment of
ordnance compounds, whereas Alternative 3 involves final off-site treatment or disposal of
spent carbon. Alternative 4 (subsurface barrier) would also effect a control on the further
spread of contaminant. Under Alternative 1 (no action) the migration and spread of the
groundwater contamination would continue until the final remedy is implemented.
With each of the alternatives, except no action, there is some measure of uncertainty in
terms of effectiveness. The effectiveness of the groundwater extraction and disposal
components of Alternatives 2 and 3 can be fairly well controlled and monitored during
operation. The uncertainty in the laboratory analysis of RDX concentrations does effect
the accuracy of the boundary of containment. The uncertainty in the effectiveness of the
UV/oxidation system with any necessary polishing treatment and activated carbon system
should be controlled through regular treatment effluent monitoring. Alternative 4 has the
highest level of uncertainty related to the ability to construct an effective barrier to
prevent further groundwater flow.
9.2 Compliance with ARARs
The purpose of the Interim Remedial Action is to contain or isolate contaminated
groundwater in the Shallow Aquifer so as to minimize further migration of contaminants
from the site until the final remedy if implemented. This interim action is neither
intended to restore the aquifer to drinking water conditions nor to at.tain all federal and
state applicable or relevant and appropriate requirements (ARMs) relating to cleanup of
the aquifer. The Navy, EP A, and Ecology expect that such ARMs will be met by the
final remedy to be selected for the site.
The ARARs for this interim remedy relate to the disposal of groundwater that is extracted
and treated during implementation of the interim remedial action. Alternatives 2 and 3
include discharge of treated groundwater back into the aquifer that currently supplies a
portion of the water supplies in the communities of Olympic View and Old Bangor.
If the treated groundwater is returned to the aquifer, the groundwater cleanup standards
established under the Model Toxies Control Act, WAC 173-340-720, are relevant and
appropriate chemical-specific treatment standards for water to be discharged.
Requirements of the State Underground Injection Control Program, WAC 173-218, are
applicable action-specific ARARs for the design of the injection wells.
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The substantive provisions of Sec. 402 of the Federal Oean Water Act, as codified in 40
CPR 122, will be applicable treatment standards for the effluent discharging into surface
waters.
The treatment technology for the extracted groundwater under Alternatives 2 and 3 will
meet these ARARs. There are not ARARs identified for Alternatives 1 and 4 since no
treatment is involved.
9.3 Reduction 0/ Toxicity, Mobility, or Volume by Treatment
Alternatives 2 and 3 both reduce mobility by removing and treating groundwater
contaminants. Alternatives 2 and 3 differ in the method used to reduce the toxicity and
volume of contaminants. Alternative 2 (UV/oxidation treatment) would provide final
treatment and thus primary reduction in toxicity and volume of contaminants. Alternative
3 (carbon adsorption treatment) would 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 would then require final off-site treatment
by incineration. Alternative 4 would reduce the further spreading of contaminants
(mobility) and thereby reduce the volume of groundwater needing treatment under the
final remedy, but it would not reduce the toxicity. Alternative 4 does not include a
treatment process. The no action alternative does not achieve any of these goals.
9.4 Short-Term Effectiveness
Alternatives 2 and 3 can be implemented within a IS-month period after Record of
Decision signature; however, the implementation schedule for alternative 2 is predicated
on the UV/oxidation treatability study. Groundwater containment can be.effected within a
short period of time following initiation of pumping. The construction required during
implementation of Alternatives 2 and 3 should only cause minor disturbance at the site
which will not increase the current site risk to workers or the surrounding communities nor
result in adverse impact to the environment. No impact to surrounding communities is
anticipated due to noise during construction given the large distance (approximately 1.5
miles) to the nearest off-base community and the nature of the construction involved in
implementing either of these alternatives.
Alternative 4 would require a long construction period to implement and consequently
would not be effective in the short-term. This alternative is not a treatment process.
Impacts due to noise from construction are anticipated in the vicinity of the site but not to
surrounding communitic"s given the distance.
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9.5 Long-Term Effectiveness and Permanence
This criteria does not apply to interim actions and consequently was not a major
consideration in the selection of the remedy.
Although implemented under an Interim Remedial Actio~ Alternatives 2 and 3 would
permanently decrease the mobility, toxicity, and volume of groundwater contamination.
Alternative 2 would provide permanent on-site treatment of groundwater contaminants.
The final groundwater remedy for the site may require groundwater cleanup to levels
below the interim action groundwater containment level under alternatives 2 and 3. The
interim action conciinment level however does encompass the bulk of the mass of
contamination. The residual risk associated with the groundwaters with RDX
concentrations below 80 p.g/L is low, given the distance from current drinking water
receptors and the travel time of the contaminants.
Alternatives 2 and 3 include disposal of the treated groundwater back into the aquifer.
However, the groundwater will be treated to meet ARARs and the residual risk of the re-
injected Water will be less than the most restrictive risk threshold of 10"' established under
the NCP. The effectiveness of the treatment will be monitored during operation to
minimize the potential for disposal of water out of compliance with treatment criteria.
Alternative 4 will require a major construction phase to install the subsurface barrier prior
to controlling further contaminant migration and its effectiveness is highly dependent upon
knowing the site conditions, which are still under study, and the quality of construction.
The effectiveness of Alternative 4 would be limited by leakage, especially at the bottom of
the barrier.
9.6 Implementability
Alternatives 2 and 3 could be implemented from a technical standpoint without difficulty
following further analysis to determine the optimum placement and operation of
groundwater extraction wells. One extraction well is currently in place. The system can
also be expanded and utilized as part of the final remedy for the site, if selected.
Groundwater treatment and disposal are required for Alternatives 2 and 3. Of the two
treatment options, UV/oxidation (Alternative 2) is the most implementable since treatment
by activated carbon is presently limited by the facilities which handle disposal of the spent
carbon. The water disposal will involve injection into the aquifer by wells or infiltration.
Injection wells are easier to construct and implement than an infiltration basin at the site.
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Alternative 4 would be difficult to implement because it would require a subsurface barrier
to be constructed at an unusually great depth (to 150 feet below ground surface).
Therefore, it would require a detailed engineering analysis to design the subsurface barrier
prior to implementation.
9.7 Cost
Alternative 1 is the least expensive alternative in the shon term but is more costly in the
long term, since groundwater contamination will continue to spread over a larger area,
which will likely require treatment by the final remedy. Alternatives 2 and 3 have
approximately the same estimated present worth costs of $2,500,000. The UV/oxidation
system (Alterative 2) is anticipated to have a higher capital cost but lower operations and
maintenance (O&M) costs. Carbon adsorption has lower capital cost but requires
incineration of the spent carbon. Alternative 4 (S8,000,000) is the most expensive,
particularly if the long-term costs of ultimately treating residual groundwater remaining on
the site are considered.
Tables 3, 4, and 5 present the basis of comparative cost estimates for interim remedial
action alternatives. These costs were based on 1991 dollar figures. A discount rate was
not applied since the estimated duration for the interim action is only 2 years. The cost
estimates provide an accuracy of + 50 percent to -30 percent in accordance with EP A
guidelines.
9.8 State Acceptance
The State concurs with the selected interim remedial action at Site F and comments
received from Ecology have been incorporated into this Record of Decision.
9.9 Community Acceptance
Based on comments received during the public review period and at the public meeting,
the public generally accepts the proposed plan as descnbed in the attached
Responsiveness Summary. The major issue raised by the public was the impact of
groundwater extraction on groundwater supplies from a quantity standpoint. The disposal
option preferred by the public was placement of the treated water back into the Shallow
Aquifer. This method of disposal was selected based on public preference,
implementability, and cost.
'.
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10.0 THE SELEcrED REMEDY
The selected interim remedial action for this site is Alternative 2: Contaminant Migration
Containment by Groundwater Extraction and Treatment by Ultraviolet/ Oxidation. This
alternative is preferred because it best achieves the goals of the evaluation criteria in
comparison to the other alternatives. This alternative was selected over Alternative 3,
which differs only in the treatment method, because it employs an innovative technology
and provides on-site treatment with permanent reduction in the toxicity and volume of the
groundwater contaminant.
The elements of the preferred interim remedial action alternative include:
~ Extracting groundwater from the Shallow Aquifer to minimize further migration of
ordnance constituents;
~ Treating the extracted groundwater by Ultraviolet/Oxidation process below federal and
state groundwater quality standards;
~ Disposing of the treated groundwater back into the Shallow Aquifer on base by
groundwater injection into wells or by infiltration using a recharge basin. The injection
wells or recharge basin would be located outside the identified zone of aquifer
contamination and will likely be located upgradient of the site to hydraulically enhance
. containment; and
~ Monitoring of the effectiveness of the interim remedial action (groundwater
containment and treatment) and provide design information, as applicable, for the final
remedy;
The components of the selected interim remedial action are discussed in more detail
below.
10.1 Feasibility 01 Groundwater Extraction
A groundwater flow model was used to evaluate groundwater extraction rates and the
effectiveness of the extraction system for containing groundwater with RDX concentrations
greater than or equal to 80 Jl.g/L The model used was FIowpath, which is a
two-dimensional, steady state finite difference groundwater flow model. The model was
used to simulate the capture zone (the portion of the aquifer contnDuting flow to the
extraction system) based on site-specific hydrogeologic data collected during the on-going
RIIFS for Site F. The assumed hydrogeologic parameters used for the modeling were:
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~ Unconfined (water table) aquifer conditions;
~ Hydraulic conductivity of 10-2 em/see, based on average values obtained from in situ
hydraulic conductivity testing and grain size analyses;
~ Horizontal hydraulic gradient of 0.003, based on water table COntour maps produced
from monthly data; and
~ Effective porosity of 0.25, taken from literature values for medium sand.
A variable elevation for the bottom of the aquifer (i.e., top of the underlying aquitard) was
input to the model, based on a contour map of the aquitard surface produced from the
RIIFS drilling data.
Model Results. The groundwater modeling results indicate that extraction of groundwater
from the Shallow Aquifer is feasible. The results indicate that an extraction system
pumping a total of 150 to 200 gpm will COntain all groundwater with RDX concentrations
at or above 80 p.g/L Figure 6 shows the distrIoution of RDX in the Shallow Aquifer
including the 80 p.g/L contour which encompasses the groundwater having a concentration
at or above 80 p.g/L The concentration contours of TNT are also shown on Figure 6.
The TNT distnoution is representative of the other ordnance constituents in terms of
relative mobility in the groundwater. The RDX containment zone of 80 p.g/L encompasses
the TNT and the other ordnance constituents. The model indicates that three wells
pumpmg at variable rates totaling approximateJy 175 gpm will affect the necessary
containment, which is generally consistent with results obtained previously from a different
groundwater model (RESSQ).
Figure 7 presents the RDX concentration contour map and estimated groundwater
capture zone induced by extraction well pumping.
The model results (i.e., number of wells and pumping rates) presented herein are
preliminary and do not represent final design for an extraction system. Additional
hydrogeologic data will be collected and more detailed groundwater flow analysis
performed during the ongoing RIfFS. Additional field data include results of aquifer
pumping tests which included extensive monitoring of response in wells completed in
' varying zones of the aquifer. Further analysis will include development of a more detailed
predictive model of the groundwater flow system which will be used to assess contaminant
movement and groundwater flow conditions under varying extraction and injection
scenarios. These data together with the additional groundwater quality data collected at
the site will be integrated with existing data to optimize a groundwater extraction system
during the design phase of the Interim Remedial Action.
The interim action design will also be based on the findings of a currently on-going
ordnance treatability study. This study is designed to verify the effectiveness of using
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UV/oxidation system to treat low-level contamination of groundwater by ordnance
compounds and to tailor a treatment system for use at Site F. The study includes both
laboratory-scale and field-scale components.
10.2 Containment Level o{ RDX in Groundwater
This interim action is designed to minimize further migration of groundwater
contamination. Since this interim action should also be consistent with the final remedy to
be selected for the site, the containment level needs to consider minimum (threshold)
action levels as outlined in applicable Superfund Directives (Table 1).
The containment level is the concentration of RDX in groundwater which will be
prevented from further migration. It does not represent an ARAR. Considering the
. range of potential risk goals addressed under the state and federal programs (e.g., 10'" to
10~ potential lifetime cancer risks due to drinking water consumption), the corresponding
cleanup standards for RDX in groundwater range from 80 /lg!L to 0.8/lg!L. The
containment level based on a risk of 10"', calculated in accordance with OSWER Directive
9285.6-03, is approximately 80 /lg!L (Table 1).
It is important to note that the calculated risk level for RDX has changed during the
course of interim remedial action development, from 30 /lgIL to 80 ./lg!L. The
containment level for RDX of 30 /lg!L was in effect at the time of issuance of the final
Proposed PIan for Interim Remedial Action and the comment period which occurred in
February 1991. The RDX containment level was based on Region 10 exposure factors
which were contained in the EPA Region 10 Statement of Work for RIJFS Risk
Assessment. The revised RDX containment level of 80 /lg!L is based on exposure factors
adopted by EP A Region 10 consistent with the OSWER Directive 9285.6-03.
Since containment at the 80 /lg!L (upper-bound) level would address most of the mass and
risk associated with all chemical releases from Site F, a lower containment value was not
considered appropriate for an interim action. The 80 /lg!L meets the 10'" risk goal and
also would not preclude the development of other cleanup remedies for any future
remedial action to be taken at the site.
Because this is an interim action, chemical specific ARARs are only invoked as they relate
to the disposal of the extracted groundwater after treatment. Consequently all
groundwater extracted during this Interim Remedial Action will be treated to a cleanup
level which complies with these ARARs. The water treatment levels (ARARs) are
presented in Table 2.
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10.3 Effectiveness 01 Treatment Technology
Ultraviolet/Oxidation (UV/Oxidation) is the proposed treatment technology for treatment
of the ordnance contaminated groundwater at Site F. It is an innovative technology which
has been shown to be successful in treating complex organic compounds including
ordnance compounds (e.g., 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 the hydroxyl radical. This hydroxyl radical will
aggressively attack and breakdown complex organic compounds (such as ordnance) by
initiating a series of oxidative reactions and converts them into components such as carbon
dioxide, water, and nitrate. Although relatively minor quantities of ordnance 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.
The technology has been shown to be effective on munitions; however, the application at
Site F may require treatment of very low levels of ordnance at a relatively high flow rate.
Existing case studies identified were conducted at lower flow rates than those anticipated
at Site F, in addition the level of treatment was not as stringent as that planned for Site F.
A treatability study is CUITently on-going to verify that the treatment system is effective in
meeting the low-level treatment and high flow rate requirements of this interim action at
Site F.
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 wiD be coupled with the UV/oxidation system to complete the treatment
process prior to disposal.
10.4 Disposal 01 Treated Groundwater
The preferred alternative presented in the Proposed Plan for Interim Remedial Action at
Site F presented several options for disposal of treated groundwater. The treated
groundwater wiD meet ARARs prior to disposal. The disposal options initially considered
as part of this interim action included discharge to sewer, discharge to surface water, or
infiltration through a recharge basin. These options were presented to the public at the
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Public Meeting. A majority of comments expressed concern for impacts to the availability
of groundwater due to groundwater extraction and suppon for clisposal of treated
groundwater back into the Shallow Aquifer.
In response to the public preference and based on comparison of each of the clisposal
options, recharge back into the Shallow Aquifer on base via one of two methods has been
selected as the preferred disposal option. The two methods being considered include
injection of the treated groundwater through specially designed wells or infiltration through
.a recharge basin. Both would occur on base and would be located outside the identified
zone of groundwater contamination. The injection or recharge area may be located
upgradient of the groundwater contamination and could be used to enhance containment.
The benefits to this clisposal method include facilitating on-base clisposal and mirtimizing
concern for depletion of the groundwater resource. Groundwater recharge could be
designed to assist in preventing contaminant migration and accelerate contaminant
removal. This method of clisposal would be more cost-effective than clischarge to a
sanitary sewer or piping to a surface water discharge point.
If disposal directly to the Shallow Aquifer is found to have limitations during the design
phase then the contingency method will be discharge to an existing on-base upland surface
water feature. This disposal will in effect provide recharge to the Shallow Aquifer.
11.0 STATUTORY DETERMINATION
The Navy's and EP A's primary responsibility, under their legal CERCLA authorities, is to
ensure that interim remeclial 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 S~ 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, given the limited scope of the action.
Finally, the statute includes a preference for remedies that employ treatment that
permanently and signifi~ntly reduce the volume, toxicity, or mobility of hazardous wastes
as their principal element.
-------
The seleCted interim remedial action for Site F at SUBASE Bangor meets the statutory
requirements for the extraction, treatment and disposal of contaminated groundwater.
The goal of the interim remedial action is to minimize the further spread of ordnance
contaminated groundwater. Overall remediation goals for groundwater cleanup will be
addressed in the selected final remedial action.
11.1 Protection 01 Human Health and tJu Environment
The seleCted Interim Remedial Action will proteCt human health and the environment
through minimi7ing the further spread of contaminants in the groundwater, thereby
reducing the threat to drinking water supplies located beyond the current contamination
boundaries. The treatment of the extracted contaminated groundwater will be to a level
protective of human health and the environment. The contaminants (2,4,6- TNT, RDX,
nitrobenzene, 2,4- and 2,6-DNT, 1,3,5-TNB, 1,3-DNB, and other minor waste constituents)
will be permanently removed from the groundwater through the treatment process which
includes destruction by ultraviolet light and oxidation. As necessary, the effluent from this
treatment process will be further treated by a polishing treatment to assure that the
disposed water does not constitute an unacceptable potential risk to human health and the
environment.
11.2 Compliance with Applicable or Relevant and Appropriate Requirements
The seleCted remedy of drawing in contaminated groundwater at a rate sufficient to
minim;'7e the further spread of significant levels of contamination and the subsequent on-
site treatment, and discharge of the treated groundwater will comply with all applicable or
relevant and appropriate chemical-, action-, and location-specific requirements (ARARs).
The ARARs are presented below.
11.2.1 Action-S1JI!c(fic ARARf
~ 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 the extraction wells.
~ Requirements of the State Underground Injection Control Program (Chapter 173-218
WAC) as approved under the Safe Drinking Water Act, establishes design standards for
injection wens.
-------
. State of Washington requirements for hazardous waste operations conducted at
uncontrolled hazardous waste sites as set fonh in WAC 296-62 (Part P), establish safe
operating procedures.
. Federal Oean Water requirements for discharge of treatment system effluent to the
waters of the United States as set forth in 40 CPR 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.
. State of Washington Hazardous Waste Management Act (Chapter 70.105 RCW)
requirements for dangerous waste and extremely hazardous waste as codified in
Chapter. 173-303 WAC may apply depending upon any treatment residuals created. No
dangerous wastes have been identified to date.
11.2.2 Chemical-$pecific~
Groundwater extraction/treatment activities will meet the following chemical-specific
ARMs:
. Since the treated water will be returned to the aquifer that currently supplies part of
the water supply to the communities of Olympic View and Old Bangor, the cleanup
standards established under the Model Toxies Control Act, as codified in WAC 173-340-
720, are relevant and appropriate for treatment of the extracted water.
. Oean Water Act Section 402 (40 CPR Parts 121-125) for effluent discharge may be
applicable if it is necessary to use an alternative to the injection well disposal of the
treated water.
11.2.3 Location-Specific ~
There are no location-specific ARMs for this interim action.
11.2.4 Land D~osal Restrictions
The selected remedy will not involve the placement of RCRA hazardous wastes on site.
This being the case, the Land Disposal Restrictions would not apply.
-------
11.2.5 Other Criteria. Advisories. or Guidance To-He-Considered (TBO
No other criteria, advisory, or guidance are considered necessary for implementation of
this interim remedial action.
11.3 Cost Effectiveness
The selected Interim 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 Alternative 3; however, 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 and provides a groundwater
extraction, treatment, and disposal system which could be incorporated into the final
remedy for groundwater cleanup. The use of granular activated carbon would require off-
site treatment where the efficiency of the destruction process could not be assured. The
selected remedy assures 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. .
11.4 Utilization of Permanent Solutions and Alternative Treatment Technologies
or Resource Recovery Technologies to the Maximum Extent Praeticable
Although the selected interim remedial action has certain features of a permanent solution
due to its use of a treatment technology, this is a limited scope action and is not intended
to provide a final remedy for this site. The minimization of further significant contaminant
spread in the groundwater through the extraction and treatment of contaminated
groundwater will permanently reduce the toxicity, volume, and mobility of contaminants by
. achieving significant destruction of the contaminants in the groundwater through ultraviolet
light and oxidation. The treatment process for the extracted groundwater will be designed
to meet or exceed state and federal standards for the protection of human health and the
environment prior to recharge.
11.5 Preference for Treatment as Principal Element
While this interim action remedy does employ a treatment technology which addresses the
threat of future ingestion/inhalation of contaminants in the extracted groundwater, this
action is being undertaken primarily to limit the spread of the contaminants within the
shallow aquifer. The statutory preference for remedies employing treatments which
permanently and significantly reduce the toxicity, mobility or volume of the hazardous
-------
substances, pollutants, or contaminants as a principal element will be addressed fu)]y in the
final decision document for this operable unit.
U.O
DOCUMENTATION OF SIGNmCANT CHANGES
The selected interim remedial action is the preferred alternative presented in the
Proposed Plan. There are no significant changes to the components of the preferred
alternative except for the containment level of RDX in the groundwater.
The containment level is the concentration of RDX in the groundwater which will be
prevented from further migration. The containment level was based on a risk goal of 10"
(potentia!" lifetime cancer risk due to drinking water consumption) consistent with OSWER
Directive 9285.6-03.
The calculated 10-4 risk level for RDX has changed during the course of interim remedial
. action development, from 30 J.1.g/L to 80 J.1.g/L. The calculated containment level for RDX
was 30 J.1.g/L at the time of issuance of the final Proposed Plan for Interim Remedial
Action and the comment period which occurred in February 1991. The RDX containment
level was initially based on Region 10 exposure factors in effect at the time of the
proposed plan. The revised RDX containment level of 80 J.1.g/L is based on national
exposure factors consistent with the OSWER Directive 9285.6-03. There has, however,
been no change in the risk threshold target of 10-4.
RECORD.rod
-------
Table 1. Comparison or Maximum Concentrations o(Chemicals Detected at Site F
with EPA-Superfund Calculated Risk Levels for Remedial Action (a)
Maximum SUc F EP A-SuperlllDd
GroUDdwalcr CaJcuJalcd Risk
CODCeaCnltJoa !..eyel
Cbcmka.l Ia ~ (b) Ia uw'L (a)
MEI'ALS AND INORGANICS:
Barium 44.0 1,000.0 c
Cadmium 3.0 B 10.0 c
Ctromium 11.0 B 50.0 c
Copper 41.0 1,000.0 c
Lead 13.0 15.0 c
Mercury 4.0 2.0 c
Nickel 22.0 730.0 d
Nitrate-N 81,000.0 10,000.0 c
Silver &.0 B 50.0 c
Zinc: 190.0 B 5,000.0 c
ORDNANCE:
2,4,6- Trinitrotoluene 58,000.0 18.0 d
2,4-DiJUtrotoluene 290.0 13.0 e
2,6-Dinitrotoluene 30.0 13.0 e
l,3.S- Trinitrobenzene 987.0 1.8 d
I.3-Dinitrobenzene 1.200.0 3.7 d
Nitrobenzene 1.030.0 1&.0 d
RDX 28.500.0 83.0 e
OTHER. ORGANICS:
Acetone .150.0 BN 1.800.0 d
Bis(2~tbylbcxyl)phthalatc 610.0 BN 650.0 e
Di-a-butyl phthalate 2.0 E 3,650.0 d
Di-a-oayl pbthalate 1&.0 3,650.0 d
EDdrin 0.1 0.2 c
HepcacbJor 0.1 2.0 e
H?---II1oc epoxide 0.1 No Data
Mdbytene Chloride 610.0 BN 610.0 e
2,4,5- TP (Silva:) 0.7 10.0 c
N01ES:
a. From EPA..QSW'ER Direaives 9285.6-03 (Marc:b 1991).
b. From Current Situatioo Report, SUBASE Bangor (Halt CrowIcr, 1989).
c. Sued 00 DriotinC Water Maximum Cootamiaaot Lc:Yds
d. Sued on IftYeDtioq on noo-canccr risk at a Hazard QUOtient of 1.
e. Sued on a threshold cancer risk of 1 in 10,000.
Data Qualifiers:
B Chemical also dctcaed in labo~tory blanks..
E Estimated concentration.
N Compound DO( detected durinC n:samplinC.
Page 28
I
-------
Table 2 . SIIIIUDaIy o( W8ler T~tmea& ObJecUY." . ARAR.s . (or ~r SIIe If
Proposed lalerim AcUoa
SIIIIUDaIy 0( W8ler T~tmea& ObjecUY." (or Pumped Grouadw8ler
Compound Concenrralions in ugtL
MTCA (a) Method B Propoled
Wiler Cleanup SCandatd Tn::acmeat
Objeaiva
Groundwater Surface Water
Niente-N 10,000 10,000 10,000
2,4,6- TriDicrocolueac 3 10 3
2,4-DiDicrocolueac 0.1 1 0.1
2,6-DiDicrocolucne 0.1 1 0.1
1,3.5.TriDicrobcazcnc 0.8 10 0.8
I.3-DiDicrobcazcnc 2 20 2
NilrobeazcDc 8 110 8
RDX 0.815 (c) 12 5 (b)
NOTJ::;S:
(a) Modd TCIIIia Concrol Aa (MTCA), Cleanup Rqujaliona. Chapter 173-340 WAC. Febnwy 28. 1991.
(b) The c:urreat pracbcaI quaalilaUoa limil Cor RDX ia 5 "IlL wt1icII defiDea IIIe compiiaoce deanup exlnceaualion Cor potencial
driDkiDC water apoIW'C exlodiliOlll ill accordance wilil MTCA.
(c) AR.ARa - AppUcabie or RelCYUlt and Appropriate Rcquircmeaa.
. Toxidty and BioconcentratioD Data Used to Compute Cleanup Standards
Ora! EPA
Reference Ora! ora!PoteDcy
Doaeill Cucer Slope ill
ChemicaJ IDCItI~ Source Group (1D8IkI~)" Source BCF (b) Source (c)
Nitnate.N 1.0 IRIS (a) D 1 E.uimated
2,4,6- TriDicrocolllCllC 5 x 10'" IRIS C 3x lr IRJS 21 Table 5.7
2,4-DiDicrocoluCIIC NO B2 6.8 X 10" IRJS 2S Table 5.7
2,6-DiDicrotollleDe ND B2 6.8 x 10" IRIS 13 Table 5.7
1,3.5- TriDitroOeDzeDe 5 x 10" IRIS D 21 E.uimated
I.3-DiDiqntwft7~ 1 x 10'" IRIS D 21 Euimated
NilrObalzeDe 5 x 10'" IRIS D 21 Ealimated
RDX 3 x 10" IRIS C 1.1 X 10" IRIS S Table 5.7
(a) UA (IY1MS). Ultepated KJIIt wOrmaClOft SyslCID (005). U{Occ oc: aDd IJCYeiOptDCDt, eatal uitena and
.h~lDCIIt Omc:e.
(b) Biocoaceatralioa FICtCI'.
(c) Cumm Situalioa Report few Sita C. D, Eo F. N8Y8J Submarine 8uc, Baap. WuhiDaum, prepared by Hut CtowIer. 1989.
NO . Noc Defermiaed.
EOOR QUALITY
. ORIGINAL
-------
Table 3 - Cost Estimate for Alternative 2: Groundwater Extraction
and Treatment by UV 1000dation
TASK Qty Unit Unit COR Cost IRc:fc:rencc
CAPITAL COSTS
GroW1dw8ter Extrac:tiOI1
Recovery wen, 3 EA 30.000 90.000 1
Recovery PuIDp8 aDd Piping 3 EA 5.000 15.000 I
IDjoc:tioa Wc1la 3 EA 30.000 90.000 I
SUBTOTAL 195,000
GrowIdW8ter Trcatmc:m
Lab TCltillg ILS 20.000 20.000 2
Holding TanJa 4 EA 50.000 200.000 I
PuIDp8 aDd Piping I EA 50.000 50.000 I
UV/Ox Syltem. 200 gpm I EA 600.000 600.000 2
Deaip Levd ExpJoraaoa I EA 50.000 50.000 I
Deaip. RemedWioA Mgmt. I EA 100.000 100.000 I
SUBTOTAL 1.020.000
OPERATION AND MAINTENANCE
(Buod 011 2 yeus of opcruioI1)
GrowIdw8tct ExtnctiDn I EA 100.000 100.000 I
Growadw8tct Tre:atmcII1
UV/Qx Syatem iIIpuu ADd ",.i............. 200.000 TgaJ S 1.000.000 2
Dilcharp MoUorillg 1 EA 100.000 100.000 1
Daip.. Jl...._u.tioa Mgmt. 1 EA 100.000 100.000 I
SUBTOTAL 1.300.000
TOTAL ESTIMATED COST: 2.515.000
REFERENCES USED IN COST TABLES:
1. Prcviou8 Experience.
2, Reed. D.. 199Ob. p~ Commll"~ from Doug Reed of SoIardIcm. IK., to
Ravi Bh8aa of Hart CroWleI'. IK. November 21. 1990.
...JI9IL_1
EOOR QUM_: j .
" ORIGINAL
-------
Table 4 - Cost Estimate for Alternative 3: Groundwater Extraction
and Treatment by Cubon Adsorption
TASK Qty IUnit I Unit CoSt CoSt !Reierence
CAPIT AI. COSTS
VroUildwaccr Em-aaion
Recovery wen. 3 EA 30.000 90.000 1
Recovery Pumpa ADd Piping 3 EA 5.000 15.000 1
lAjccQon WcUa 3 EA 30.000 90.000 1
SUBTOTAL 195.000
Oroundw8lCl' Trcatmcat
Lab Testing 1 LS 10.000 10.000 3
Holding Tanks 4 EA 50.000 200.000 1
Pump8 aDd PIping 1 EA 50.000 50.000 1
Carbon SyltCm. 200 gpm 1 EA 300.000 300.000 3
Design Lovd ExpJol'lltioa 1 EA 50.000 50.000 1
Design. Rcmcdiadon Mgmt. 1 EA 100.000 100.000 1
SUBTOTAL 710.000
OPERATION AND MAINTENANCE
(Bued on 2 yan of operaIion)
Vroundw8lCl' Eurac:tion 1 EA 100.000 100.000 1
OrouDdW8lC:r T I'C8tIDaIt
Catbon D~ ADd Rcp!8CCIDcat 2EA 600.000 1.200.000 3
M.iftr~.-v"-o 1 EA 200.000 200.000 1
Diacharp Moaitorinl 1 EA 100.000 100.000 1
Design. Jl.....-liation MgmL 1 EA 100.000 100.000 1
SUBTOTAL 1.600.000
TOTAL ESTIMATED COST: 2.50S.000
REFERENCES USED IN COST TABLES:
1. Provtoua ExpericDco.
2. Reed. D.. 199Ob. Penoaa1 CommUDic:8cioa from Caul Rood of SoWdiem. IDe.. to
Ravi BhaQa of Hart CroW.cr. IDe. November 21. 1990.
3. HADIOQ. R.. 1990. Penoaa1 CommllDic8tioa from Robcn HADIOQ of Cameron-Yakima. Inc.. to
Ravi Bhacia of Hart Crowtcr. IDe. July S. 1990. This facility is not currattly able
to 8oCc.c:pt ordnanc:e for dispou1. however. thac COltS were provided for
purpoaca of C08I colDp8r'isoa.
106)1.... ..I
~OOR QUALITY
'., ORIGINAL.
-------
Table 5 - Cost Estimate for Alternative 4: 'Slurry Wall
TASK Qty I UlUt Unit COIIt COIIt IReference
CAPITAL COSTS
GrollDdwata' Exttaction
Slurry Wall. Dcaip. ud Mgmt. 1.000.000 EA 8 8.000.000 1
SUBTOTAL 8.000.000
OPERATION AND MAINTENANCE 0
(Baed oa 2 ycan of operadoG)
TOTAL ESTIMATED COST: 8.000.000
REFERENCES USED IN COST TABLES:
1. EP A, 1987. .Compcadium of Cosa of Remedial Tcchnologica at Hazardoua WUtc8 Sitca. .
EPAl6OOI2-87/037. Hazardous Wuze Engineeriug ReIearcA Labonr.ory, USEPA, CiDI:imwi. Ohio.
loQl9ca.wal
POOR QUALITY
ORIGINAL
-------
Generalized Regional Map
Note: Base map prepared Irom 'Puget Sound Country Washington'
published by Kroll Map Company. undated.
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-------
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J- '463-'9 4/9'
-------
Shallow Aquifer Water
Table Elevation Contour
Map
January, 1991
9 P-y W» MonHoiing Wed
Location and Number
244.30 Spot water Tabte
Elevation in Feel
244.O- Waler Table Elevation
Contour in Feel
(Contour Interval = 10 Fool)
Generalized Groundwater
Flow Direction
Not*: Depth to walm measurements codnclod
on 1/9/91.
POOR QUALITY
ORIGINAL
400
BOO
Scale in Feel
HAKTQtOWSER
J-1463-19 4/91
-------
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location and Number
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level Oata
ROX Concentration Contour
in uQ/l
TNT Concentration Contour
in uQ/l
POOR QUALIrt
ORIGINAL
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-------
R
oncentration Contour Map and Estimated G
dwater Capture Zone
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MOOllonng Well
locallOn and Number
RDX Concenlralion in ug/l
RDX Concentration Contour
in ug/l Based on Screening
level Data
Groundwaler E'xlracllOn WeB
locallon Wllh Groundwalp.r
Flow lones
Eshmaled Groundwaler
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(;roundwaler Flow OtrecllOn
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HAmCROWSER
J- 1463-'9 8/91
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