United States
Environmental Protection
Agency
Office of
Emergency and
Remedial Response
EPA/ROD/R10-92/034
April 1992
f/EPA Superfund
Record of Decision:
N.A.S. Whidbey Island - Ault
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NOTICE
The appendices listed in the index that are not found in this docurYMtnt 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 supp6emental material is, however. contained in the administrative record
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50272.101
REPORT DOCUMENTATION 1'. REPORT NO.
PAGE EPA/ROD/R10-92/034
I ~
:I. A8dpi8n1'8 ~ No.
4. TII8 8nd SUb4ItI8
SUPERFUND RECORD OF DECISION
N.A.S. whidbey Island - Ault Field, WA
First Remedial Action - Interim
7. AuIhor(8)
s. A8part Da88
04/21/92
6.
6. l'Wf
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EPA/ROD/R10-92/034
N.A.S. whidbey Island - Ault Field, WA
First Remedial Action Interim
Abstract (Continued)
areas and associated soil"and ground water contamination. The primary contaminants of
concern affecting the ground water are VOCs, including TCE; and metals, including
chromium and lead.
The selected remedial action for this site"includes containing the solvent contaminated
ground water using extraction, followed by onsite treatment using metal precipitation,
air stripping, and carbon adsorption; reinjecting the treated water into the affected
aquifer; and monitoring ground ~ater. The estimated present worth cost of this remedial
action is $2,201,000, which includes a total O&M cost of $1,230,000 for 3 years.
PERFORMANCE STANDARDS OR GOALS: Chemical-specific ground water clean-up goals are based
on SDWA MCLs and State Model Toxics Control Act (MTCA) and include TCE 4 ug/l (MTCA);
1, 1, 1-DCA 200 ug/l; 1,1-TCA 0.5 ug/l (MTCA) ; 1,1-DCE 0.07 ug/~ (MTCA); 1,2-DCE 70 ug/l
(MTCA); vinyl chloride 0.02 ug/l (MTCA);.carbon tetrachloride 0.3 ug/l (MTCA); chromium
80 ug/l (MTCA); and lead 4 ug/l (MTCA). Because this action does not constitute a final
remedy for the ground water, subsequent actions will fully address risks posed by
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Declaration of the Record of Decision~
Decision Summary, Responsiveness Summary,
and Administrative Record Index
:.t
for
Interim Remedial Action
Naval Air Station Whidbey Island
Operable Unit 1, Area 6
Oak Harbor, Washington
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DECLARATION OF THE RECORD OF DECISION
SITE NAME AND LOCATION
Naval Air Station Whidbey Island, Ault Field
Operable Unit 1, Area 6""
Oak Harbor, Washington
Sf A TEMENT OF BASIS AND PURPOSE
This decision document presentS the selected interim remedial action for Area 6 Landfill at the Naval Air
Station Wbidbey Island, chosen in accordance witli. the Comprehensive--Environrnental Re5ponsc,
Compensation, and Liability Act, as amended by the Superfund AmendmentS and Reauthorization Act,
. and, to the extent practicable, the National Oil and Hazardous Substances Pollution Contingency Plan.
This decision is based on the administrative record file for this site.
:.1
The U.S. Navy is the lead agency for this decision. 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, operating under the authority of the Model Toxics Control Act
(MTCA), concurs with the selected remedy.
ASSESSMENT OF 'mE SITE
This interim remedial action will provide an opportunity to significantly reduce the mobility of ground
water contaminantS, 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
actionselected in this Record of Decision (ROD), may present an imminent and substantial endangerment
to public health, welfare, or the environment. The selected interim remedial action is 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 THE REMEDY
This interim remedial action addresses the primary risk posed by this site to the public by controlling the
spread of a contaminated plume of ground water. This operable unit is one of three operable unitS for
the site. The function of this interim action is to reduce the risk associated with the continued spread of
the contaminated ground water plume at Operable Unit I through containment, on-site treatment and .
disposal. While this remedy does address one of the primaiyrisks at Area 6, con~inued study is
necessary to determine the ultimate remedy for the entire operable unit and ultimately the site as a whole. -
Major componentS of the interim action remedy include:
.
Extraction of ground water in the shallow aquifer beneath Area 6 using extraction wells
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.
Treating the extracted ground water using metal precipitation, air stripping, and vapor
phase activated carbon;
.
Dischargin-g the treated water back to the shallow aquifer by irrigation or reinjection; and
.
Monitoring of the ground water and treated water to measure the effectiveness of the
action.
DECLARATION
..
This interim action is protective of human health and the environment, complies with Federal and State
applicable or relevant and appropriate requirements and is cost effective. Although this action is not
intended to be a permanent remedy, it utilizes pennanent solutions and treatment to th~ maximum extent
practicable, given the limited scope of the action, and thus is in furtherance of the 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, mobil ity or volume as a principal element, although
partially addressed in this remedy, will be addressed at the time of the final response action. Subsequent
actions will fully address the risks posed by the conditions at this operable unit.
:J
Because this interim action will result in hazardous substances remaining on site above health based
levels, a review will be conducted to ensure that this action continues to reduce the threat to human health
and the environment within five years after commencement of the remedial action. Review of this interim
action will be ongoing as the Navy continues to evaluate permanent remedial alternatives to support th~
final remedy selection for this operable unit.
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Signature sheet for the foregoing Naval Air Station Whidbey Island - Area 6, Interim 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.
CW~
R. R. Penfold
Captain U.S. Navy
Commanding Officer
Naval AIr Station, Whidbey Island.
za ~.e.IL IG'I <-
Date
:.t
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Signature sheet for the foregoing Naval Air Station Whidbey Island - Area 6, Interim 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.
~ q t}~AA~~
Dana A. Rasmussen
Regional Administrator, Region 10
United States Environmental Prot~ion Agency
APR 2 1 1992
Date
. - .
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Signature sheet for the foregoing Naval Air Station Whidbey Island - Area 6, Interim Remedial Action.
R6COrd of Decision, betWeen the United States Navy and the United States Environmental Protection
Agency, with concurrence by the Washington State Department of Ecology. .
~ ;;I.. " =/J14 RA/
Carol Fleskes, Program Manager
Toxies Cleanup Program
Washington State Department of E~ology
{,[fJA<.1 ~~, /qq.:l-.
I Date '
'.I
. .. . .
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TABLE OF CONTENTS
Section
DECISION SUMMARY
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.0 INTRODUCTION.. '"." . . . . . . . . . . . . . . . . . . . . . - . " . . . . . - . - . . . . . . . . .
2.0 SITE NAME, LOCATION AND DESCRIPTION. . . . . . . . . . . . . . . . . . . . . . . . . .
3.0 SITE HISTORY AND ENFORCEMENT ACTIONS........................
.
4.0 COMMUNITY RELATIONS. . . . . . . . . . . . . . . . - - . . . - . . - . . . . . . . . . . . . . .
5.0 SCOPE AND ROLE OF OPERABLE UNITS. . . . . - . - . . - - ." - .: . . . . . . . . . . . . . .
6.0 SUMMARY OF SITE CHARACTERISTICS -... - - - . . - - . . . - . - . - . . - . . . . . . -
6.1 Physical Conditions. . . - . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.2 Contaminant Characteristics. . . . . . . . . - - . - . . - . . . - . . . . . . . . . . - - . . . . .
7.0 SUMMARY OF SITE RISKS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
:J.
8.0 DESCRIPTION OF INTERIM ACTION ALTERNATIVES. . - . . . - - . . . . - . . . . . . .
8.1 Alternative 1 - No Action. . . . . . . . . . . . . . . . - . . - - - . . . - . . . . . . . . - . . .
8.2 AJtemative 2 - Grour.d Water Extraction with treatment by Ultraviolet/Oxidation. . . .
8.3 Alternative 3 - Ground Water Extractioi1 with Treatment by Air Stripping. . . . . . . .
8.4 Alternative 4 - Ground Water Diversion by an Up gradient Subsurface Barrier - . . . . .
9.0 COMPARATIVE ANALYSIS OF ALTERNATIVES. . . . . . . . . . . . . . . . . . . . . . - .
10.0 SELECTED REMEDY. . . . . . . . . . . . . . . . . . . . . . . . . . . - . . . . . . . . . . . . . . .
10.1 Feasibility of Ground Water Extraction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.2 Selection of Containment Level for Trichloroethene in Ground Water. . . . . . . . . . .
10.3 Effectiveness of Treatment Technology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.4 Treated Water Disposal. . . . . . . . . . . . . . . . . . . . . . . - . . . . . . . . . . . . . . .
11.0 STATUTORY DETERMINATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.1 Protection of Human Health and the Environment. . . . . . . . . . . . . . . . . . . . . . .
11.2 Compliance with Applicable or Relevant and Appropriate RequirementS. . . . . . . . .
11.2.1 Action-Specific ARARs ..................................
11.2.2 Chemical-Specific ARARs . . . . . . . . . . . . . . . . . - . . . . . . . . . . . . . . .
11.2.3 Location-Specific ARARs .............,... - . . ". . . . . . . . . . . . .
11.3 Cost Effectiveness. . . . . . . . . . . . . . . . . . . . . ,",.". . . : . . . . . . . . . . . . . . .
11.4 Utilization of Permanent Solutions and Alternative Treatment Technolog~es or Resource
Recovery Technologies to the Maximum Extent Practicable - - . - . . ~ . . . . - . . . . .
11.5 Preference for Treatment as Principal Element. . . . . . . . . . . . . . . . . . - . . . . . .
12.0 DOCUMENTATION OF SIGNIFICANT CHANGES. . . . . . . . . . - - - . . . . - - . . . . .
ATTACHMENT A - Responsiveness Summary'
ATTACHMENT B - Administrative Record Index
VI
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Number
LIST OF TABLES
Summary of Treatment Standards (ARARs) for Area 6 NAS Whidbey Island Interim
Remedial Action. . . '.' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Number
1
Site Map
.. .. .. .. .. .. .. .. " .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..
LIST OF FIGURES
2
Area 6 Features. . . . . . . . . . . . . . . . . . . . . . . . '.' . . . . . . . . . . . . . . . . . . . . . .
3
Ground Water Capture Plume Map
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. . .
vii
Pa!!e
19
Page
2
3
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DECISION SUMMARY
1.0 INTRODUCTION
In accordance with Executive Order 12580, the Comprehensive Environmental Response, Compensation,
and Liability Act, as amended by the Superfund Amendments and Reauthorization Act, and, to the extent
practicable, the Nationai' ,Oil and Hazardous Substances Pollution Contingency Plan, the Navy is
, addressing contamination by undertaking an interim action. The selected interim action has the approval
of the U.S.> Environmental Protection Agency (EPA) , the concurrence of the Washington State
Department of Ecology (Ecology), and is responsive to the expressed concerns of the public. The
selected interim remedial action will comply with applicable or relevant and appropriate requirements
(ARARs) promulgated by the Washington State Department of Ecology (Ecology), the U.S.
Environmental Protection Agency (EP A), and other state and federal agencies.
This action is being taken to address the plume of contamination found to be expanding in the ground
water under the Navy's landfill west of Highway 20, south of Clover Valley Road and east of Goldie
Road. This area is known as Area 6. This interim action is being taken to retard or stop the spread of
the plume until an overall plan can be developed.
2.0 SITE NAME, WCA TION AND DESCRIPTION
".1
Naval Air Station Whidbey Island (NAS) is located on Whidbey Island in Island County, Washington,
at the north end of Puget Sound and the eastern end of the Strait of Juan de Fuca (Figure 1). The S.tation
is comprised of two main installations, Ault Field and Seaplane Base. Area 6, which comprises a pOrtion
of Operable Unit 1 at Ault" Field, is the subject of this action and is located to the northwest of the City
of Oak Harbor.
NAS Whidbey Island was commissioned in 1942. Currently, the station's mission is to operate and
maintain Navy aircraft and aviation facilities and provide associated support. Since the 19405, operations
at NAS Whidbey Island have generated a variety of hazardous wastes. These wastes were disposed of
using what were in the past considered acceptable disposal practices. Wastes consisted of solvents, oily
sludges, thinners, and other hazardous compounds. Dumping of hazardous wastes at Area 6 occurred
between 1969 and 1988.
Area 6 is comprised of 260 acres and is located in the southeast corner of Ault Field (Figure I). It is
bordered by Ault Field Road to the north, State Highway 20 to the east, the Oak Harbor municipal
landfill on the south and southwest, and privately-<>wned generally undeveloped, forested or logged off
land to the west. A gravel road extending south from Ault Field Road provides access to the property.
Area 6 is fenced and access is restricted to authorized personneL Landfill operations have been ongoing
since 1969. While disposal of hazardous waste no longer continues, municipal solid waste from NAS
Whidbey' Island is disposed of in elongated trenches in the southeast part of Area 6. Locations curren~y
used for disposal at Area 6 shown on Figure 2 include: " C ",' , '
.
Current Landfill Trench - consists of one large trench in the southwestern part of the site.
.
Asbestos Pits/Ponds - including two small ponds (now filled) in the centiaI part of the
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igure 1 - Site Map
\1
.
.
:_..1
f~-.._..J
CITY OF
OAK HARBOR
AREA 6
.._.._......--..--..~
-"-"SEAPLANE BASE !
.
I
.
.
I
~~
o
Scale In Miles
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. re 2 - Area 6 Features
1~ ,
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--------------../
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INSTALLATION
BOUNOARY ~,
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C\1
;....
-.:
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: CcJ :1
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f-
Ct)
----
"
AREA 6
LANDFILL
\
\
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o
Q
< I
o
0:
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'/' I
, r----~
- \.........~- . . ""\)
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.
Wood Pile - c~nsists of a large pit filled with waste wood that is burned periodically to
reduce waste volume. It is located east of the former landfill trench area.
.
Rubble Pit/Pond - a small pond between the asbestos pits/ponds and the wood pile
containing rubble and various other wastes.
.
Animal Remains. Trench - recently ~nstructed along the landfill access road; contains
animal remainS.from road kills and other unidentified sources.
.
Rubble/Gravel Piles - consist of various piles of construction debris rubble, gravel, and
sand. These are not shown on Figure 1.
Past disposal locations shown on Figure 2 for Area 6 include:
.,'
.
Former LandfiH Trenches - large area in the western part of the landfill. Tren<:hicg
began at the north end and progressed southward. Liquids and sludges containing
hazardous waste constituents were disposed of here from 1969 until 1983 in the northern
tWo-thirds of the trench area; maximum quantity over the 14 years is estimated to be 2.2
million gallons.
.
Acid Pit - a small pit located near the western end of the gravel loop road. It has been
filled in with local sand and gravel. The pit was used from the early 1970s to the early
1980s. The tOtal volume of liquid wastes (acids, caustics, solvents) disposed of here over
12 years is estimated be 300,000 to 700,000 gallons.
.
Oily Sludge Pit - believed to consist of either a small pit or a series of east-west oriented
trenches located south of the gravei loop road. The total volume of liquid and sludge
wastes disposed of over five years (1969 to mid-1970s) is estimated to be 100,000 to
600,000 gallons.
.
Asbestos Trenches - consisted of several east-west trenches located near the oily sludge
pit. The quantity of wastes disposed is unknown.
.
Waste Oil Tanks - either one or two oil tanks (10,000 gallons) were used to store oil
during an unknown time interval. These tank(s) were located north of the gravel loop
road next to the loading platform. The quantity of waste disposed of is unknown. The
tank(s) were removed to an unknown location prior to early 1988.
.
Solvent/Caustic Waste Tank - a small tank « 10,000 gallons) was used for storage of
solvent or caustic wastes. It is not known when this tank was used or exactly where it
was located, but it was probably situated in the gravel loop road area. The quantity of
waste disposed of is unknown. The tan.k(s) were removed to an unknown location prior
to early 1988.
'. ;.'.-.'.
.
Hazardous Waste Storage Area - this area contained full, partially-fuU, and empty metal
drums. It was located around the west end of the gravel loop road, probably above the.
filled-in acid pit. The quantity of waste disposed of is unknown. The area was in use
from the early 1980s until about 1986. All of the drums were removed to an unknown
location prior to early 1988
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.
Oily Sludge, Asbestos, Rubble Trenches/Piles - this area was located in the east part of
the landfill trench area. Gravel was also disposed of in this area. The quantity of waste
disposed of is unknown. .
.
Former Animal Remains Trenches - used for disposal of animals killed by aircraft or
vehicles on NAS Whidbey Island. It was located near the west end of the gravel loop
road and was i.n use until 1989. The quantity of waste disposed of is unknown.
.
Rubble/Gravel Piles - consist of various piles of rubble, gravel, and sand located along
the western side of Area 6 in the landfill trench area. The beginning date of disposal
activities is unknown but continues to the present. The quantity of waste disposed of is
unknown. .
Area 6 is a ground water recharge area underlain by three aquifers: shallow, intermediate and deep. In
a portion of Area 6, in the vicinity of the former hazardous waste storage area, the soil and the ground
water in the shallow aquifer is contaminated. The contaminants include, but are not limited to, the
volatile organics: 1,1, I-trichloroethane, trichloroethene, I, I-dichloroethane, 1, I-dichloroethene, 1,2-
dichloroethene, vinyl chloride, and the metals: chromium, arsenic and lead.
The nearest populations are located along the south-eastern edge of Area 6 at the Aulde Holland Inn and
Trailer Park, approximately 3300 feet from the gravel loop road, and at residences located along Goldie
Road, approximately 1200 feet west of the Area 6 western boundary. .
:t
3.0 SITE IDSTORY A.."fD ENFORCEMENT ACTIONS
0.
In response to the requirement.~ of the Comprehensive Environmental Response, Compensation, and
Liability Act of 1980 (CERCLA), the Department of Defense (DOD) established the Installation
Restoration (lR) program. The U.S. Navy, in turn, established a Navy IR program to meet the
requirements of CERCLA and the DoD IR program. From 1980 until early 1987, this program was
called the Navy Assessment and Control of Installation Pollutants (NACIP) program. A set of procedures
and terminologies were developed under this program to describe the NACIP activities which were
different from those used by the U.S. EPA in the administration of CERCLA.. As a result of the
implementation of the Superfund Amendments and Reauthorization Act of 1986 (SARA), the U.S. Navy
has dropped NACIP and adopted the EPA CERCLA/SARA procedures and terminology (U.S. Navy,
1988; Naval Operations, Chief, 1988).
":.'
Responsibility for the implementation and administration of the IR program has been assigned to the Navy
Facilities Engineering Command (NA VFACENGCOM). The Western Division (WESTDIV) of
NA VF ACENGCOM has responsibility for the western states. Engineering Field Activity, Northwest
(EFA' Northwest) has responsibility for investigations of NAS Whidbey Island and other Naval
installations in the Pacific Northwest and Alaska.
In February 1990 NAS Whidbey Island's Ault field was listed as ~a-'Superfund Site on the EPA's National
Priorities List (NPL). As a result of the listing, pursuant to a Federal Facility Agreement (FFA) signed
by the Navy, EP A and Ecology, in September 1990, the Navy is conducting a Remedial
Investigation/Feasibility Study (RI/FS) to determine the nature and extent of soil and ground water
contamination, and to. evaluate alternatives for the cleanup of contaminated areas.
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Previous Investigations at NAS Whidbey Island
The Navy conducted an Initial Assessment Study (IAS) at NAS Whidbey Island under the NACIP
program (U.S. Navy, 1984). The lAS, consisting primarily of a records search, was completed in
September 1984. A more focused follow-up investigation and report, NAS Whidbey Island Current
Situation Report (CSR), was completed in January 1988. The CSR describes the results of an
investigation of water, soil, marine animals, and marine sediments on and adjacent to NAS Whidbey
Island sites. After the CSR.. was completed, further investigations were proposed for areas where
contamination was verified and where unverified conditions indicated further investigations were
appropriate.
While the CSR was being prepared", EPA Region 10 performed preliminary assessments at NAS Whidbey
Island's Ault Field and the Seaplane Base to evaluate risks to public health and the environment using the
Hazard Ranking System (HRS). The HRS provides a methodology to score sites based on a number of
factors including proximity to surface and ground water, past site activities, types of pol!utants on a site,
and potential threat to the public and environment.
In late 1985, the EPA proposed that Ault Field and the Seaplane Base be nominated to the NPL. In
February 1990, these sites were officially listed on the NPL. EPA's inclusion of Ault Field and the
Seaplane Base sites on the NPL is based on the number of waste disposal and spill sites discovered, types
and quantities of hazardous constituents (such as petroleum products, solvents, paints, thinners, jet fuel,
pesticides, and other wastes), and the potential for domestic wells and local shellfish beds to be impacted
from wastes originating from the station.
:.t
During March 1988, the Navy evaluated the IAS and CSR documents, and records of waste management
practices at NAS Whidbey Island. Based on the evaluation. the Navy determined that 44 areas (all areas
recommended by previous studies, those evaluated by EP A during HRS scoring, and five additional areas)
would be included in the NAS Whidbey Island investigation under the Navy IR program.
In the summer of 1989, prior to beginning remedial investigation field efforts, an accelerated Initi3.1
Investigation of Area 6 was performed (Martin Marietta, 1989). The investigation at this location
assessed whether ground water contamination was present and if users of ground water in the vicinity
were or could be impacted.. Although ground water contamination was confirmed, current ground water
users were not impacted. A Technical Memorandum (Martin Marietta, 1990a) describes the investigation
and results. Based on the Initial Investigation, an Action PI~ for the Remedial Investigation/Feasibility
Study was developed in 1990.(Martin Marietta, 1990b).
In 1989, as part of a statewide program to monitor the quality of drinking water supplies, the Washington
Department of Health tested 13 public wells located in a one-mile radius around the Area 6 and the Oak
Harbor landfills. No organic compounds were found. Results indicated that the drinking water supplies
were not impacted.
In early 1991.., during the Rl/FS investigation, ground water sampling results indicated that vinyl chloride
concentrations exceeded Maximum Contaminant Levels for drinking water (MCLs) and that contamination
may have migrated offsite. As a result, in May, 1991, the Navy called upon the Department of Health .
to sample one public and six private wells in the vicinity of Area 6. These wells are located to the south,
east, and southwest of the current landfill boundary. No evidence of contamination from Area 6 was
detected in these seven wells. Nevertheless, the Navy began a program of voluntary water hook-ups for
those land owners potentially affected.
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4.0 COMMUNITY RELATIONS
A more detailed discussion of the site contamination is. presented in the "Work Plan for Operable Unit
No.1 Naval Air Station Whidbey Island" (CTO-OOO5) February 1, 1991. These documents are available
for public review at the information repositories listed below. The specific requirements for public
participation pursuant to CERCLA section 117(a), as amended by SARA, include releasing the Proposed
Plan to the public. This was ~one on January 3, 1992. Those landowners included in the water hookup
program were sent special mailIngs informing them of the Proposed Plan. The Proposed Plan was placed
in the Administrative Record and information repositories. Attachment B presents the Administrative
Record Index.
Information Repositories;
Oak Harbor Library
3075 300th A venue West
Oak Harbor, Washington
Phone: (206) 675-5115
98278
NAS Whidbey Island Library
Building 103
Oak Harbor, Washington 98278
Phone: (206) 257-2702
~I
Sno-Isle Regional Library System
Coupeville Library
788 N. W. Alexander
Coupeville, Washington 98239
Phone: (206) 678-4911
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
Phone: (206) 476-5775
Notice of the availability of the proposed plan, notice of a public meeting to discuss the proposed plan,
and the public comment period was published in the Whidbey News Times on January 01, 1992. A
public meeting was held on January 27, 1992.
A total of- 4 comments were received by the Navy concerning Ui.e 'proposed plan. The. comments are
summarized and responses presented in the Responsiveness Summary, Attachment A.
Community relations activities have established communication between the citizens living near the site,
the Navy, EP A, and Ecology. Discussion between the different groups for informational purposes and
suggestions on the project has been open. The actions taken to satisfy the statUtory requirements also
provided a forum for citizen involvement and input to the interim action decision.
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Community relations activities at the site include:
.
Creation of. a Community Relations Plan;
.
Technical Review Committee meetings with representatives from the public and other
governmental agencies;
.
Meetings with nearby property owners to discuss the water hookup program;
.
Issuance of the Proposed Plan in fact sheet format to facilitate discussion;
.
Future public meetings to present information related to the RIfFS activities at the site;
.
Fact sheetS to provide updates on the'work being performed and major findings at all
operable unitS, .
5.0 SCOPE AND ROLE OF OPERABLE UNITS
Area 6 along with the Area 5 landfill comprise Operable Unit 1. There are three operable unitS at NAS
Whidbey Island, Ault Field. Operable unit 1 is geographically separate from the other unitS.
.'
The Interim Remedial Action is being taken to prevent the continued spread of contaminantS in the
shallow aquifer beneath Area 6, reduce the risk of impact to existing and future ground water users, and
initiate a strategy that is, to the extent possible, consistent with future actions including the final remedy;.
This action addresses only containment of col1tanlinated ground water. The final remedy will address
both ground water and soil contamination. The final ground water remedy will likely include
containment, treatment and disposal componentS similar to those proposed here.
6.0 SUMMARY OF SITE CHARACTERISTICS
6.1 Physical Conditions
The ground water system beneath Operable Unit 1, consisting of a shallow unconfined aquifer a."ld
intermediate and deep confined aquifers, was investigated. In addition to the three major ground water
unitS, three independent perched aquifers have been identified in the vicinity of Monitoring Wells H -1-2s,
MW-3A, and 6-5-18. These local perched aquifers, with water table elevations ranging from 109 to 157
feet above MSL (approximately 20 to 30 feet below the ground surface) lie above silt, silty sand, and till
and occupy gravelly sands of the Upper Advance Outwash and part of the Vashon till. The unconfined
shallow aquifer with a water table elevation of 78 to 91 feet above MSL, occurs within sands of the
Lower Advance Outwash as well as the upper sandy portion of Unit 1 of the Whidbey Formation. With
a water table elevation of 66 to 76 feet above MSL, the confined intermediate aquifer consistS of the silty
sands of the Whidbey Formation Unit 2. The confined deep aquIfer, or sea level aquifer, with a water
table elevation of 13.5 to 13.7 feet above MSL, occupies sands with some silt within Unit 4 of the
Whidbey Formation. The shallow aquifer is substantially above and not believed to be hydraulically
connected to the deep aquifer.
-------
The ground water flow direction in the shallow aquifer is gently arcuate froni south-southwest in the
northern part of Area 6 to due south in the central part of the site to south-southeast in the south and
under the Oak Harbor Landfill. The flow velocity in the shallow aquifer is estimated to be between 92
and 456 feet per year. Flow direction in the shallow aquifer at Area 5 is generally northwest. Therefore,
a local ground water divide appears to exist generally beneath Ault Field Road. The ground water
gradient in the shallow aquifer across Operable Unit 1 ranges from 0.0016 to 0.0038 feet/feet and is not
effected by seasonal changes. . Although the spatial distribution of the wells in the intermediate aquifer
is not conducive to the detennination of a ground water gradient, the direction of flow seems to be
northeast. The flow velocity in the intennediate aquifer is estimated to be between 8 and 27 feet per
year. Ground water in the deep aquifer flows uniformly southeast under Area 6, although the gradient
appears to increase slightly in tl1e downgradient direction. The gradient across the site is very low and
averages 0.000037 feet/feet. The flow velocity in the deep aquifer is estimated to be between 0.04 and
5 feet per year.
Rising head slug test data analyzed using the Hvorslev method was 'used to calculate hydraulic
conductivities for the aquifers. The estimated hydraulic conductivities in the unconfined aquifer range
from 0.0019 to 0.0028 cm/s in Area 5 and from 0.0007 to 0.0024 cm/s in Area 6. Also in Area 6, the
estimated hydraulic conductivities range from 0.0002 to 0.0007 cm/s in the intermediate aquifer and from
0.0008 to 0.0027 cm/s in the deep aquifer.
6.2 Contaminant Characteristics
:J.
Preliminary findings of the remedial investigation at the Area 6 landfill include:
.
.
.,'.
.
.
Contamination was found in the soil and ground water at Area 6. The main sourc~ of
the contaminants appears to be the formcr hazardous waste storage area. Primary
contamina.,ts of concern in the shallow aquifer appear to be chlorinated solvents. The
highest reported concentrations of chlorinated solvents as measured in soil gas were
located approximately 300 feet northwest of the former hazardous waste storage area.
In some instances, concentrations of total solvents in the vapor phase approach 104,000
parts per billion (Ppb). Analysis of soils revealed concentrations of solvents approaching
1400 ILg/kg located one foot below the surface at well location 6-1-4.
The contaminants include known and suspected human carcinogens which have been
found to be mobile in ground water systems.
Contamination of the ground water in the shallow aquifer beneath Area 6 was confirmed.
Chlorinated solvent concentrations of over 2,000 ILg/L were detected. Elevated levels of
contamination. appear limited to the shallow aquifer.
Preliminary findings suggest that chlorinated solvent contaminants have migrated off of
the NAS Whidbey Island property along the western boundary of the Area 6 landfill.
The lateral extent of the soil gas contamination appears' to be limited to approximately
500 feet outside of the northwestern landfiU'"boundary, directly west of the former
hazardous waste stOrage area. No domestic or other water supply wells are affected at
this time and none appear to have .any imminent threat.
-------
7.0 SUMMARY OF SITE RISKS
The continued movement of contaminants already in the ground water currently poses the most significant
human health risk at the site. This ground water could potentially affect domestic water supplies.
Before a clear understanding of the health risks posed by Area 6 can be determined, more information
must be collected and a quan~itative health Risk Assessment must be performed. The Risk Assessment
will be conducted during the ongoing RIfFS. Based on existing data, chlorinated solvents and degradation
products have been detected in the ground water and are considered to pose the most significant risk.
Contaminants detected include, but are not limited to, TCE, trichloroethane, dichloroethene,
dichloroethane, and vinyl chloride. The vinyl chloride concentration is above the MCL established by
the EP A for protection of drinking water aquifers. In addition, chromium, arsenic and lead have been
detected. The detected contaminants are likely to spread if no action is taken.
Contaminants have consistently been observed beneath the former hazardous waste storage area in die
shallow aquifer. Existing data indicate that TCE is present in the ground water as far as 1600 feet to the
south of Area 6, although the actual boundary of the contamination is uncertain.
8.0 DESCRIPTION OF INTERIM ACTION ALTERNATIVES
'.I
This action is being taken because there is a release into the environment and there is a threat to human
health. The purpose of this interim action alternative evaluation is to choose a method of treatment that
will prevent the further spread of solvents in the shallow aquifer. Alternatives were ev3.1uated using a
st.reamlined selection technique that followed published EPA ~Jidance. Additional information on t~e
alternatives is available in "Technical Memorandum" dated December 27, 1991 which is available at the
information repositories listed above. A total of four alternatives were evaluated in detail for possible
implementation at Area 6:
Alternative 1 - No Action (Required for comparison purposes)
Alternative 2 - Ground Water Extraction with Treatment by Ultraviolet/Oxidation
Alternative 3 - Ground Water Extraction with Treatment by Air Stripping
Alternative 4 - Ground Water Diversion by an Upgradient Subsurface Barrier
The volume of ground water with a trichloroethene concentration above 5 parts per billion (Ppb) has been
chosen to define the portion of the plume which will be captured by this interim action. This is not a
cleanup standard; standards will be established as part of the RIfFS process. However, it is believed that
this capture zone will effectively include the other contaminants of concern and was selected because it
provides a readily measurable target value. The plume boundary will be updated as new info~ation
from the ongoing RIfFS becomes available.
For all alternatives, a three year operation was assumed for comparison purpo'ses. Costs are calculated
using net present worth analysis. .
8.1 Alternative 1 - No Action
This alternative is included for evaluation purposes. It is comprised of continued monitoring of the
ground.water and does not contain any active measures to reduce the migration of the contaminant plume
or to reduce the threat to public health or the environment. Alternative 1 would require only quarterly
sampling and analysis costs.
-------
Capital Cost: $ °
3- Y ear Operations and Maintenance Costs $ 250.000
Total Estimated Cost $ 250,000
8.2 Alternative 2 - Ground Water Extraction with treatment by Ultraviolet/Oxidation
This' alternative would pump ground water from the shallow aquifer beneath the landfill by the use of
multiple extraction wells. The extracted water will be treated onsite using ultraviolet light and chemical
oxidation (UV loxidation). The g.round ,water wells would be arranged so that they intercept the
contaminant plume, halting the spread of the plume ar.d capturing ground water that has concentrations
of TCE in excess of 5 ppb. The capture zone of the three proposed wells is displayed on Figure 3.
Ground water computer modeling indicates that a combined pumping rate of approximately 450 gallons
per minute is sufficient to prevent the spread of the contaminants. The effects of pumping at this ratE:
on neighboring wells in not known at this time.
.
UV/oxidation treatment is a proven method of destroying organic chemicals in water. In this technique
the contaminated water is pumped into a reaction tank where it is exposed to ultraviolet light and an
oxidizing agent such as hydrogen peroxide. The UV light acts to increase the effectiveness of the
oxidation reaction which converts the organic waste into carbon-dioxide, chloride salts and water. ~e
treatment units are electrically powered and require minimal field installation work. A pre-treatment
system is required to remove minerals and metals (e.g., iron, sodium, manganese) from the water which
would reduce the effectiveness of the treatment system. The treated water will be discharged to the land
surface through an irrigation and reinjection system to recharge the shallow aquifer upgradient of th~
former hazardous waste storage area. TIle selection of an upgradient recharge area is to assist in the
flushing action on the conta.rninantc; and to create a hydraulic barrier to the inflow of new ground water.
The treated water, air emissions and solid residues will be discharged or disposed of in accordance with
applicable federal and state requirements.
:.1
~ ;.
Capital Cost:
Extraction Well Field and Piping
UV IOxidation System
Pre-treatment System
Treated Water Discharge System
Engineering & Contingency
3- Y ear Operations and Maintenance Cost:
Monitoring and Site Maintenance
Extraction System
Pre-treatment System
UV IOxidation System
Total Estimated Cost
$
$
$
$
$
219,700
1,740,000
400,000
50,000
428,000
$
$
$
$
$
250,000
60,000
250,000
512.500 '
, 3,910,200
8.3 Alternative 3 - Ground Water Extraction with Treatment by Air Stripping'
This alternative utilizes the same extraction system as Alternative 2 but treats the water using an air
stripper in place of the UV IOxidation system. In an air stripper, contaminated water is pumped to the
top of a tower (2-20+ feet in height and 1-10 feet in diameter) where it is sprayed on a bed of packing
material (pVC, polypropylene, or ceramic in various shapes and sizes). 'As the water triclcles downward,
-------
igure 3 - Ground Water Capture Plume Map
~t
l'
C;
J.
l= ~
c ~
UJ
Z
£-<
Z
i::J
o
CIl
;,...
~
~
t:I
~ I
'"
....
()
....
o
....
76 f
=
~-
--o[ !
L...---- \
PREDICTED GROUND WATER FLOW, Whid~y Island. Area 6
RESULTING FROM WITHDRAWL OF 150 GPM, FROM 3 WELLS
----- Ground water surface elevations
-- -- . Ground water contaminant concentration isopleth
. PROPOSED EXTRACTION WELL LOCATION
500
. .
~
!
1000 n.
I CROUND 1fATER FLOW VECTOR 1~
y" ARROt SI7I PROPORTIONAL TO CI FLOW RATE !
I
11111 III! I
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a fan provides a flow of fresh air up through the packing material to enhance the evaporation of organics
from the water. The volatil~ contaminants are transferred from the ground water to the air. The air will
be passed through pollutiot:l control equipment as required to capture the contaminants for subsequent
treatment, recycle, or destruction.
Air stripping is a proven, eff~ive, and reliable means of removing volatile organic compounds from
water. The treatment units are electrically operated and require minimal field installation work. A pre-
treatment system as discussed in Alternative 2 would be required. The treated water will be discharged
to the land surface through an irrigation and reinjection system to recharge the shallow aquifer to the
north of the former hazardous was~e storage area. The solid residues will be discharged or disposed of
in accordance with applicable federal and state requirements. The air pollution control technology is
assumed to be activated carbon, although the actual technology will be determined during the design
phase based on applicable regulations. .
Capital Cost:
Extraction Well Field and Piping
Air Stripper System
Pre-treatment System
Air Pollution Control System
Treated Water Discharge System
Engineering and Contingency
:J.
3- Year Operations and Maintenance Cost:
Monitoring and Site Maintenance
Extraction System
Pre-treatment System
Stripper System
Air Pollution Control System
Total Estimated Cost
$
$
$
$
$
$
219,700
120,000
400,000
65,000
50,000
117,000
$
$
$
$
$
$
250,000
60,000
250,000
70,000
600.000
2,201,700
8.4 Alternative 4 - Ground Water Diversion by an Upgradient Subsurface Barrier
This alternative is comprised of an impermeable slurry wall constructed below the ground surface to
divert the flow of upgradient ground water around the former hazardous waste storage area of the landfill.
A slurry wall is constructed by excavating a three- to four-foot wide trench from the surface to the bottom
of the contaminated aquifer, a depth of approximately 120 feet. A slurry is used to provide structural
stability during trenching. Soil and clay materials (bentonite) displace the slurry and form the low
permeability barrier. In this alternative, contaminated ground water is not collected or treated; instead,
it is a containment action where uncontaminated ground water is diverted around the suspected source.
The migration of the contaminant plume is hindered by the reduction in the quantity of ground water
entering the plume - not from active pumping as in alternatives 2 and 3. Maintenance requirements of
the wall are minimal, requiring only quarterly inspections for integrity and surface conditions and for
ground water sampling. . .
Capital Cost:
. Soil/Bentonite Slurry Wall (1000 ft)
Engineering and Contingency
13
$
$
1,950,000
-------
Operations and Maint~nance Cost:
Monitoring
Maintenance
Total Estimated Cost
$
$
$
250,000
50.000
2,620,000
9.0 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
The National Contingency Plan lists nine criteria for the evaluation of remedial alternatives. These
criteria are described below as they apply to an interim action. The first two listed criteria represent
threshold criteria that must be m~t by the interim action alternative. The four interim action alternatives
were evaluated against these criteria to select a remedy.
Overall Protection of HUlTUln Health and the Environment - There are weils in the vicinity of the
contaminated plume that could be a pathway to human or environmental exposures. Therefore, the
. objective of this interim action is to contain the migration of the contaminant plume, treat it to the extent
practicable in keeping with the ultimate remedial goals and monitor the ground water to ensure that
populations are not being exposed. The alternatives were evaluated for their ability to meet this objective.
..'
Alternative 1, No Action does not provide protection to health or the environment and does not halt the
migration of the contamination. Alternatives 2 and 3 are protective of human health and the environment
and are able to meet the objectives established for this action. Both alternatives effectively halt the spread
of the contaminated ground water and provide onsite treatment of the captured water and do not
negatively impact the recharge capacity of the area. Alternative 4 provides some protection by slowin,g
the spread of the plume but wO'.lld not stop it. {t also would not remove any contamination from the
ground water.
Compliance with Federal and State Regult:ztWns - The purpose of the Interim Remedial Action is to
contain or isolate contaminated ground water in the shallow aquifer so as to minimize further migration
of contaminants from the site until the final remedy is implemented. This interim action is neither
intended to restore the aquifer to drinking water conditions nor to attain all federal and state ARARs
relating to cleanup of the aquifer. The Navy, EPA, and Ecology expect that such ARARs will be
addressed by the final remedy to be selected for the site.
.~ ;.
The ARARs for this interim remedy relate to the treatment and disposal of groundwater that is extracted
and treated during implementation of the interim remedial action and for products resulting from the
treatment.
Alternatives 2 and 3 include discharge of treated ground water back into the shallow aquifer. Because
the treated ground water will be returned to the aquifer, the ground water cleanup standards established
under the Model Toxies Control Act, WAC 173-340-720, are relevant and appropriate chemical-specific
treatment standards. Requirements of the State Underground Injection Control Program, WAC 173-218,
are applicable aCtion-specific standards for the design of the injection wells (if specified)..
Air emissions from the treatment process, if any, will be required to meet state ARARs for total and toxic
air emissions, WAC 173-400.
Solid residues from the treatment processes of alternatives 2 and 3 will be required to meet both federal
and state ARARs for hazardous, dangerous or non-hazardous waste as appropriate. Requirements of State
-------
Dangerous Waste Regulations, WAC 173-303, may be a relevant and appropriate action-specific ARAR
depending on the nature of the solid residues.
Alternatives 2 and 3 would be required to meet air, water and solid residue discharge ARARs.
Alternatives I and 4 would not be required to meet these standards.
Long Tenn Effectiveness and PentUlnence - Although implemented under an Interim Remedial Action,
Alternatives 2 and 3 would permanently decrease the mobility, toxicity, and volume of ground water
contamination.
The final ground water remedy for the site may require ground water cleanup to levels below the interim
action ground water contairunent level under alternatives 2 and 3. The interim action containment level
however does e'ncompass the bulk of the mass of contamination.
Alternative 2 and 3 include discharge of the treated ground water back into the aquifer. TIle water will
be treated to meet ARARs. The effectiveness of the treatment will be monitored during operation to
minimize the potential for disposal of water out of compliance with treatment criteria. The solid residue
will be disposed of at an off-site facility in accordance with the EPA Off-Site Disposal Policy (OSWER
Directive 9834.11, November 13, 1987).
:.t
Alternative 4 will require a major construction phase to install the subsurface barrier prior to controlling
further migration. Its effectiveness is highly dependent upon site conditions and the quality' of
construction. The effectiveness of Alternative 4 would be limited by leakage, especially at the bottom
of the barrier.
Reduction of Toxicity, Mobility, or Volume thrlJugh TreatmenJ - Alternatives 2 and 3 would effectively
reduce the toxicity, mobi!ity and volume of contaminants in the ground water through treatment.
Contaminants would be removed from the extracted ground water or destroyed using proven treatment
technology. Alternative 4 requires no treatment and does not result in a reduction in volume or toxicity.
Alternative 1 does not meet these criteria.
~:'
Short-tenn Effectiveness - Alternative 1 has no short-term effectiveness. Alternatives 2 and 3 can be
constructed with little or no disruptive effect on the immediate area. Air emissions, water and solid
residual disposal will be regulated by ARARs. The effects of ground water pumping on other operational
wells is unknown at this time. The treatment equipment is readily available and can be designed and
installed in less than one year with little or no impact to human health or the envirorunent. The
construction of a subsurface barrier, Alternative 4, is more substantial and potentially disruptive to the
envirorunent but can also be designed and constructed in a one year time period.
ImplemenJabiliJy - Alternatives 2, 3 and 4 utilize proven technologies in the remediation field and could
be readily implemented. The treatment plants for alternatives 2 and 3 would be manufactured off-site
and trucked to the site for assembly. The location and number of extraction welts can be readily modified
as new information becomes available. The subsurface barrier (Alternative' 4) would require a substantial
design and construction effort that, once constructed, could net b~ readily modified as new data become
available.
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Cost - Alternative 1 has minimal costS and is the least expensive. However, because it does not contain
or reduce the spread of contamination, the long-term remediation of the site may be substantially more
expensive. Alternative 2; extraction with UV/Oxidation, has an estimated cost of $3,910,200.
Alternative 3, extraction with air stripping, has the lowest 3-year cost of $2,201,700. The cost of
Alternative 4 is estimated at $2,620,000.
SttJJe Acceptance - The State.of Washington concurs with the selected interim remedial action and
commentS from Ecology have been incorporated into this Record of Decision.
Community Acceptance - Based on commentS received during the public comment period the public
acceptS the selected remedy as described in the attached Responsiveness Summary (Appendix A). The
major concern was the impact on regional ground water supplies. The selected treated water disposal
method, recharge of the shallow aquifer with the treat~ water, should limit the potential impact to the
regional water supply and help protect the availability and quality of ground ~ater.
10.0 SELECTED REMEDY
~(
The selected interim remedial action for this Operable Unit is Alternative 3, Ground Water Extraction
with Air Stripping. This remedy calls for the design and implementation of an interim remedial action
to protect human health and the environment. The goal of this remedial action is to halt the spread of
the contaminant plume. The ultimate level of remediation to be attained will be determined in a final
remedy for Area 6.
Alternative No.3 is composed of the following key recovery and process unitS:
.
Ground water extraction wells in the shallow aquifer to restrict the spread or the contaminated
ground water and capture ground water in areas that have TCE concentrations of 5 ppb or
greater
.
Treating the extracted ground water using an air stripper system constructed on Area 6
.
The treated water disposal system will be designed according to, state and federal
requirementS and will employ irrigation, reinjection or a combination of both into the shallow
aquifer
..'
.
Air emissions and residual disposal will meet state and federal requirementS
.
Continued monitoring of the ground water and the treated water to measure the effectiveness
of the interim action.
10.1 Feasibility of Ground Water Extraction
A ground water model was used to evaluate ground water extraction rates and the. effectiveness of the
extraction system for containing ground water with TCE concentrations greater than 5 ILg/L.
-------
The results of the modelling demonstrated that the con~inant plume could be contained by pumping
at a rate of approximately 150 gallons per minute from each of three extraction wells. In the baseline
case the model exhibited close agreement between measured and modeled concentrations at wells spanning
the length of the plume. Concentration contours at the southernmost boundary of the monitored area was
approximately 30-55 ppb. Additional monitoring well data from the west may be desirable to substantiate
the plume boundary in that direction.
10.2 Selection of Containment Level for Trichloroethene in Ground Water
This interim action is designed to minimize further migration of ground water contamination. Because
this interim action should also be CQnsistent with the final remedy, the containment level needs to consider
minimum (threshold) action levels as outlined in applicable guidance- but does not represent an ARAR
cleanup level.
The volume of ground water with a trichloroethene concentration above 5 partS per biilion (Ppb) has been
chosen to define the portion of the plume which will be captured by this interim action. This is not a
cleanup standard; standards will be established as part of the RIfFS process. However, it is believed that
this capture zone will effectively include the other contaminants of concern and was selected because it
provides a readily measurable target value. The plume boundary will be updated as new information
from the ongoing RIfFS becomes available.
10.3 Effectiveness of Treatment Technology
~I
Air Stripping is the selected treatment process. It is a well proven technology for the' extraction of
organic contarnina.i1ts from ground water. A pretreatment system, consisting of precipitation or gree~-
sand filtration, will be installed before the air stripper to remove dissolved metals and suspended solids
that might inhibit the operation of the air stripper or exceed discharge requirements- Residues from the
pretreatment system will be disposed of in accordance with ARARs.
Offgases from the air stripper will contain the removed volatile organic compounds. Prior to discharge
to the atmosphere, the gases will be passed through an air pollution control devise consisting of a bed of
activated carbon. The spent carbon will be recycled, reused or disposed of in accordance with ARARs.
Additional ground water sampling will be performed during the design phase of the interim action to
determine if the quantity of extracted vinyl chloride in the offgases would exceed that which could be
economically removed by activated carbon. In this event an alternative air pollution control method, such
as catalytic incineration, may be necessary. '
10.4 Treated Water Disposal
The selected discharge method for the treated water is to recharge the shallow aquifer upgradient of the
former hazardous waste storage area. This will be accomplished through the use of spray irrigation,
infiltration or reinjection wells or a combination of both. The treated ground water will meet ARARs
prior to discharge. Due to the close proximity to the approach tq one of the main runways of the Air
Station, ponding will be avoided. . : ,', "
Recharge is a proven cost-effective method for disposing of treated water. The benefits of this disposal
method include minimizing depletion of the ground water in the area and the creation of a hydraulic
barrier to the inflow of clean ground water into the contaminated area.
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11.0 STATUfORY DETERMINATION
The selected alternative for interim remedial action is protective of human health and the environment.
It meets ARARs within the limited scope of the action and is cost effective. The preferred alternative
is consistent with the statutory mandate for treatment to the maximum extent practicable. It represents
the best balance of trade-offs among the alternatives with respect to pertinent criteria given the limited
scope of the action. Because tl:tis is an interim action, review of this remedy will be ongoing as the Navy
continues to develop final remt%lial alternatives for the site.
11.1 Protection of Human Health and the Environment
The selected I~terim Remedial Action will protect human health and the environment by minimizing
through treatment the further spread of contaminants in the ground water, thereby reducing the threat to
drinking water supplies located beyond the current site boundaries. The treatment of the extracted
contaminants will be to a level that meet ARARs and is protective of human health a.'I.d the environment.
The contaminants will be permanently removed from the ground water through the treatment process
which includes air stripping. As necessary, pretreatment and post-treatment processing will be employed
to assure the disposed water and treatment residues do not constitute an unacceptable risk to human health
or the environment.
11.2 Compliance with Applicable or Relevant and Appropriate Requirements
~I
The selected remedy will comply with all applicable or relevant and appropriate chemical-, action- and
location-specific requirements (ARARs). The ARARs are presented below.
H.2.1 Action-Specific ARARs
".
.
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 the Construction and Maintenance of Wells), establishes criteria for the
construction and maintenance of 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
wells.
.
State of Washington requirements for hazardous waste operations conducted at uncontrolled
hazardous waste sites as set forth in WAC 296-62 (part P), establishes safe operating
procedures.
.
Federal Clean Water Act requirements for design standards for waste water treatment plants
(40 CFR 122). .
.
Water Pollution Control Act (Chapter 90.48 RCW} and the Water Resources Act of 1971
(Chapter 90.54 RCW) require the use of all known and reasonable methods for controlling
discharges to surface and ground waters.
.
State of Washington requirements for fugitive emissions, WAC 173-400-040, establishes
standards for material handling during construction and operation.
-------
.
The State of Washington Dangerous Waste Regulations, WAC 173-303-, establ ishes standards
for the handling, storage and disposal of solid wastes. Disposal of treatment plant process
residues (filter cake) may also be regulated by the federal Hazardous and Solid Waste
Amendments (1984), which prohibits the land disposal of hazardous wastes unless certain land
disposal standards are met (40 CFR 268). This residue may require disposal at an approved
hazardous waste disposal site. Testing of the residue is required to determine the proper
disposal method. " '
.
Emission Standards for Hazardous Air Pollutants, WAC 173-400-074, establishes emission
standards for vinyl chloride and other hazardous, air pollutants.
11.2.2 Chemical-Specific ARARS
Ground water extraction/treatment activities will meet the following chemical-specific ARAR.s:
.
Because the treated water will be returned to the shallow aquifer beneath Area 6, the
standards established under the Model Taxies Control Act (WAC 173-340-720) or the
maximum contaminant level as established by the Safe Drinking Water Act (40 CFR 141,
142, 143) are relevant and appropriate for this discharge. These standards are summarized
in Table 1.
Table 1
- ::::::::::t::::::::::::;;:r::::::@:::~Mi#~r~ffi;~iI:~~F.i~t¥::to~J~;~:W#.~::t¥Cwi;:@tr:::::::::;:::::::;::f:{ I
.....,..................-................. ;.;.:.;.;.;.:.:.:.;,;,;,;,;,;".:.;.;.;.;.;.;.:.:.;.;-;.;.;,.:.;.;.;.;.;.;.;.;.;.;.;.;.; """"""""""""" ..... -
iilll!llill!li11Illillll!!ii!!il!I!! [[[' [[[
............................................ ;.:.:.:.;.:.:.:.'.:.:.;.:.:.:.'.;.;.;.;.:.:.:.:.:.:.:.:':':':'.
.:.:.:.:.:.'.:.:.:.:.:.:.:.:.:.'[[[' :~:i:~:~:~:i:~t:::f}~:~:::~:~:}~:}~:::~:i:~:::~'
::I:'!~!I:!:!'~ill,:!I.~~li',;,I:ill:I; ................... ...........
"::!~::::::!:~[:'lt~I.~:,!::::;;;:![:::
Trichloroethene 5 0 4 4
1 . I . i-Trichloroethane 200 200 720 200
1 . I-Dicblorocthane - - 0.5 0.5
1 . I-Dicbloroethene 7 7 0.07 0.07
1 .2-Dicbloroethene 70 70 SO' 70
Vinyl Chloride 2 0 0.02 0.02
Carbon Tetrachloride 5 0 0 .3 0.3
Chromium 'I 00 I 00 sOS SO
Lead 15 0 56 5
Swnmary of Treatment Standards (ARARs) for Area 6
NAS Whidbey Island Interim Remedial Action
:.I
Noccs: 1
2
3
4
5
6
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11.2.3 Wcation-Specific ARARs
. There is a seasonal wetlands on the Area. 6 landfill, therefore the Wetland Protection Act
(Executive Order 11990, 40 CFR Part 6, Appendix A) is an ARAR.
. The Air Station is home to two Bald Eagles, therefore the Endangered Species Act (50 CFR
81) is relevant and. appropriate to this action.
11.3 Cost Effectiveness
Both Alternative 2 and 3 meet th~. objectives of the interim action. However, the cost of Alternative 2
is significantly higher than Alternative 3, the selected remedy. The selected remedy is the most cost
effective alternative because it protects human health and the environment, attains ARARs and meets the
objectives established for the interim action in a way that is proportional to its cost. The selected remedy
will achieve the objectives of the interim action for the least amount of money. wnile the cost of
Alternative 1 is the lowest, it does not achieve the objectives of the interim action. The cost of
Alternative 4 is only slightly higher than Alternative 3, however, there are concerns about the
effectiveness of this alternative for the purposes of this interim action.
11.4 Utilization of Permanent Solutions and Alternative Treatment Technologies or Resource
Recovery Technologies to the Maximum Extent Practicable
"
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 ground water. through
extraction and treatment will permanently reduce the .toxicity, volume and mobility of contaminants by
removing the contaminants from the water and collecting them on activated carbon for off site recycling
or destruction. The treatment process for the extracted ground water 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
This action is being undertaken primarily to limit the spread of contaminants in the ground water in the
shallow aquifer beneath Area 6. While this interim action does employ treatment, 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
fully in the final decision document for this operable unit.
12.0 DOCUMENTATION OF SIGNIFICANT CHANGES
The selected remedy is the preferred alternative presented in the Proposed Plari. There are no significant
changes to the components of the preferred alternative except for ~e selection of upgradient recharge as
the treated water disposal method. . - . ..
The preferred alternative did not identify a disposal methodology for the treated ground water. The Navy
recominended, and the EP A, Ecology and the public concurred, that the treated water should be used to
recharge the shallow aquifer upgradient (north) of the former hazardous waste storage area. The selected
technique is to utilize a spray irrigation/percolation system to accomplish the recharge.
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