EPA/ROD/R10-95/113
June 1995
EPA Superftmd
Record of Decision:
NAS Whidbey Island (Ault Field)
(OU 3), Whidbey Island, WA
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FINAL .
RECORD OF DECISION
for Operable Unit 3
NAS Whidbey Island
CTO-OO74
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FINAL
. RECORD OF DECISION
FOR THE
COMPREHENSIVE LONG-TERM ENVIRONMENTAL ACTION.NAVY
(CLEAN) NORTHWEST AREA
NAS WHIDBEY ISLAND .
OPERABLE UNIT 3 '.
CONTRACT TASK ORDER NO. 0074
PREPARED BY:
URS CONSULTANTS, INC.
SEATTLE~ WASHINGTON
AND
. .
. ,.
SCIENCE APPUCATIONS INTERNATIONAL CORPORATION
BO'I"JlRT .1., WASHINGTON
PREPARED FOR:'.
ENGINEERING FIELD ACTIVITY, NORTHWEST
SOUTHWEST DIVISION, . NAVAL FACll.ITIES ENGINEERING COMMAND
. POULSBO, WASHINGTON
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DECLARATION 'OF THE RECORD OF DECISION
SITE NAME AND ADDRESS
Naval Air Station wiudbey'Island. Ault Field
Operable Unit 3, Area 16.
Oak Harbor. W ~hington
STATEMENT OF PURPOSE
This decision document presents the fmal remedial !lction for Operable Unit (OU) 3. one of four operable units at
the Naval Air Station (NAS) WhidbeYl!;land; Ault Field. Superfund' site near Oak Harbor. Washington. . The
selected remedy in this decision document was chosen in accordance with the ComprebensiveEnvironmental
Response. Compensati~n. and Liability Act of 1980 (CERCLA). as amended by the Superfund Amendments and
Reauthorization Act of 1986 (SARA), and. to the extent practicable. the National Oil and HazMdous Substances
Pollution Contingency Plan (NCP). This decision is based on the administrative record for OU 3.
This document alSo finalizes the results of the Hazardous Waste Evaluation Study. The purpose of this study was
to determine whether sufficient contamination .existed at an additional 26 areas at NAS Wbidbey Island to warrant
either further investigation. some type of remedial action. or no further action. Those decisions are included in this
Record of Decision. .
The United States Navy (Navy) is the lead agency for this decision. The United States Enyironmental Protection
Agency (EPA) approyes ~f this decision and. along with the WasbingtonState. Department of E~ology (Ecology), . '
'has participated in tbe scaping of tliesite investigations and in the evaluation of remedial action alternatives. The'
State of Washington concurs with the selected remedy. .
ASSESSMENT OF THE SITE
Actual or threatened releases. of hazardous substances from OU 3, if not addressed by implementing the response
action selected in this Record of Decision (ROD), may present an imminent and substantial endangerment to public
health. welfare. or the environment. .
DESCRIPTION OF THE REMEDY
. ..
OU 3 originally consisted of Area 16. the Runway Ditches. and Area 31. the Former Fire Training School.
Because of the need for further evaluation. Area 31 is no longer part of OU 3. Area 31 will be addreSsed as part '
ofOU 5. .
The remedial action at ~ 16 addresses ecological risks. Runway ditch sediments at several segments of the ditch
. system were found to contain chemicals that pose risks to animals. such as muskrats and benthic organisms. which
come into contact with the sediments. Chemicals of concern in ditch sediment inciude polynuclear aromatic
hydrocarbons (PAHs), total petroleum hydrocarbons (TPH). arsenic. and lead. There is no concern for human
health risks in'the nmway ditch. system. The purpose of the action is to reduce the ecological risk associated with
contamination in the ditch sediments. .'
The selected remedy for the nmway ditches is removal with on-site disposal. The action is to remove the sediment
from the contaminllted areas and haul it to the Area 6 landfill on the base. This . landfill will be capped as part of
the selected remedy for OU 1. and placement of these sediments under the cap will contain the contaminants.
. Because the concentrations' of chemicals found in the sediments do not cause the sediment. to be considered
. hazardous or dangerous waste. placement in the landfill will be permitted. The sediments will be analyzed prior
to placement to verify this conclusion. After remedial action. the NaVy can resume maintenance dredging to allow
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ST ATUTORY DETERMINATIONS
The selected remedy is protective of human health and the.environment. is in compliance with federal and state
requirements that are legally applicable or relevant and appropriate to the remedial action. and is cost-effective.
The remedy utilizes permanent solutions and alternative treatment (or resource recovery) technologies to the
maximum extent practicable for this site. However. becaUse treatment of the principal threats of the site was not
found to be praCticable. this remedy does not satisfy the statutory preference for treatment as a principal element.
Hazardous substances will be left on site above risk-based levels; therefore. the fi~e-year review will apply to this
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Signature sheet for the foregoing Naval Air Station Whidbey Island. Ault Field. Operable Unit 3. final remedial
~ction. Rccord of Dccision. between the United States Navy and the United States Environmental Protection
Agency. with concurrence by the Washington State Depanment of Ecology.
. .
.~---}~~c-
o
<2-
Captain John F. Schork
Commanding Offic::er. Naval Air Station Whidbey Island
United States Navy
4/20/95
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SignatUre sheet for the foregoing Naval Air Station Wbidbey Island, Ault Field, Operable Unit 3, final 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.
~~
Chuck Qarice
Regional AdministratOr, Region 10
United States EDvirolUDeDtal Protection Agency
."
APR 1 4 1995
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SignatUre sheer for the foregoing Naval Air Station Wbidbey Island. Ault Field.,Operable Unit 3. final remedial
action. Record of Decision. between the United States Navy and the' United States EnvironmentaJ Protection
Agency, with concurrence by the Washington State Department of Ecology.
M~~'~' ,
Program Manager, Toxies Cleanup Program
Washington State Depanmem' of Ecology
...
If 6t~ IffS-
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NAS WHIDBEY ISLAND. OPERABLE UNI't 3
U.S. Navy - CLEAN Contract
Engineering Field Activity, . Northwest
Contract .No. N62474-89-D-9295
CTO 0074
Section
2.0
3.0
4.0
Final Record of Decision
Revision No,: 0
Date: 03/29/95
Page ii' .
CONTENTS
Page
1.0
INTR.ODUCTION ,...'............,..."...,......,.....,. 1
. .
SITE ~AME, LOCATION AND DESCRIPTION. . . . ,.. . . . .. . . . . '. . . . . .
1
SITE HISTORY AND ENFORCEMENT AC11VITIES . . . . . . . . . . . . , , . .. 5
3.1 SITE HISTORY., . . . . . . , . . . . . . . , . . . . . . . . . . . . . . . . . . .. 5
3.2 PREVIOUS INVESTIGATIONS AT NAS WHIDBEY ISLAND.'. . . .. 6
CO~RELATION£............,.".".............. 7
5.0 . SCOPE AND ROLE OF OPERABLE UNIT, . . . , , ,'. ,', . . . . .'. . . . , , . , .' 9
6.0
7.0
SUMMARY' OF SITE CHARACTERISTICS. . . . , , . , . . . . . . . . . . . . . .. 9
6.1 PHYSICAL AND ENVIRONMENTAL SETI'lNG . . . . . . . . , . , . . ,. 10'
6.1.1 Geology and Hydrogeology' . . . , . . . . . . . . . . . . . . . . . . , . 10
6.1.2 Surface Water. . . . . . . . . . . . . . , . , . . . . . . . . . . , . . , . 14
6.1.3 . Ecological Setting. , , . . . . . . . . . , , , : . . . , . . . . . , . . . , 15
6.2 NATURE AND EXTENT OF CONTAMINANTS. . . . , . , , , . . . . ., 16
6.2.1 Soil.',....,."..:..,.."",'".,....,...,... 18
6.2.2 Groundwater........,.,..,..,.'",.. '. . . . . . . , .. : . , 18
6.2.3 SurfaCe water. . . . . .'. . . . . . . . . , . . '. , . . . . , . , " , ; ,'. 23
6.2.4 Runway Ditch Sediment , ~ . . . , , , , , . . , . . . . . . . , , . . , . 24 .
6,.2.5 Clover Valley Lagoon Surface Water and Sediment. . , , , , , . , 25
6.2.6 Dugualla Bay Sediment and Clam Tissue. . . . . . . . . , , , . . .. 28
SUMMARY OF SITE RISKS, , . . . , . . , . . , . . , . , . . . . . . . . . . , . . , . 29
7.1 HUMANHEALTII RISK ASSESSMENT ............... , ,....29
7.1.1 Chemical Screening . ~ . . . . . . " . , . , , . . . . . . . . ~ . , . . . . 29 "
7.1.2, Exposure Assessment, . , . . . . . . . , . , . .. . .. .. . . .. . . . . 30
7.1.3 Toxicity Assessment. . . . , . . , , , , . . . . . . .. . . . , , . . . . 33
7.1.4 Risk Characterization, , , . . .. . , , , . , . . . . . . . . . . . . . . . 34
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SAS WHIDBEY ISLAND. OPERABLE UNIT 3
C.5 !liavy - CLEAN Contract.
EnpDCCring Field Activity. Northwest
CODtnICt No. N62474-89-D-9295
CTO 0074
Section
7.2
8.0
Final Record of Decision.
Revision No.: 0 .
Date: 03/29/95
Page iii
CONTENTS (Continued)
. .
Page
ECOLOGICAL RISK ASSESSMENT. . .. . . . . . '. . . , . . . . , . . . . . 41
7.2.1 Chemical Screening. . . . . . . . . . . . . . . . . . . . . . . . . .'. . . 42
7.2.2 Exposure Assessment. . . . . . , , , , . . . . . . . . . . . . . . . . . . 43
7 ;2.3 Toxicity Assessment. . . . . . . . . , , . . . , ... . . . . . . . . . . .43
7.2.4 Risk Characterization. '. . . . . . . . , " . . . . . . . , . . . , . . . .. 44
7.2.5 Uncertainty,... .' , . . . . . . . . . . . . . . . .. . . . , . , . . . . . 51
REMEDIAL ACnON OBJECnvES . . . . '.' . . . . . . . . , . . . ',' . . , . . . . . 54
8.1 RUNWAY DITCHES, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
8.1.1 Need for Remedial Action'. . . . . , . , . . . . . . , , . . . . , . . . . 55
8,1. 2' Remedial Action Objectives. . . . . . , . . . . . . . , . . . . . . . . ; 57
8.1. 3 Cleanup Levels' ..,.....................,...". 59
8.1.4 Selecnon of Areas for' Remediation ......,.'."....,.'... 62
8.2 CLOVER VALLEY LAGOON AND DUGUALLABAY . . . . . .'. . ... 69
'. .
DESCRIP110N OF ALTERNATIVES. . . . .. . . . . ... . . . . . . . , . . . . . . . 70
9.1 ALTERNATIVE 1 - NO ACTION. . . . . . . . . . . . . . . . . . , . . . . . 71
. .
9.2 ALTERNATIVE 2 - DITCH REROUTING AND BACKFll..LING " .. 72
9.3 ALTERNATIVE 3 - SEDIMENT REMOVAL AND DISPOSAL. . . .. 7j
9,0
10.0 COMPARATIVE ANALYSIS OF ALTERNAnvES . .. . . . . . . . . . . . . . . ~ 75
. . 10.1 OVERAU.. PROTECTION OF HUMAN . .
. HEALTIi AND'TIm ENVIRONMENT. . , .'.. . . . . . . . . . . . , . . . . 75
10.2 COMPUANCE WITH APPliCABLE OR RELEVANT .
AND APPROPRIATE REQUIREMENTS (ARARS) . . . . . , . . . . . . ... 76
10.3 LONG-TERM EFFECTIVENESS. . . . . . . . . . . . . . . . . . . . . . . . . 77
10.4' REDUCTION OF TOXICITY, 'MOBll..ITY OR VOLUME
mROUGHTREATMENT .,.,....... .',..... . . . .. . . . . . .77.
SHORT-TERM EFFECTIVENESS. . . . . . . . . . . . . . . . . . . . . .. . . 77
Th.fPL.a{ENTABIllTY ."............................. 78
COST.: . . . . . . . . . . .' . . . . . . . . . . '. . . . .' . . '. . . . . ... . .' .. . . . 79
STATE ACCEPTANCE; . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
COMMUNITY ACCEPTANCE. . . .'. . . . . . . . . . . . . . .'. . . . , . . 79
10.5
10.6
. 10.7
10.8
10.9
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NAS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
Engineering Field Activity. Northwest
Contract No. N62474-89-D-9295
CTO 0074
Final Record of Decision
Revision No.: 0
Date: 03/29/95
. Page iv
CONTENTS (Continued)
Section
Page
12.0 STATUTORY DETERMINATIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
12.1 PROTECTION OF HUMAN HEALTII AND TIlE ENVIRONMENT. " 81
12.2 COMPliANCE WITIlARARs . . . . . . . . . : ; . . . .. : . : . . . . . . . ... 82
12.2.1 Chemical-Specific ARARs . . . . . .. .. . . . . . . . . . . . . . . . . . 82
12.2.2 Location-Specific ARARs ........ . . . . . . . . . . . . . . . . . 82
12.2.3 Action-Specific ARARs .......................... 82
12.2.4 Other Criteria, Advisories, or Guidance. . . . . . . . . . . . . . . . 83
12.3 COST-EFFECTIVENESS.............................. 83
12.4 UTILIZATION OF PERMANENT SOLUTIONS AND TREATMENT .
TECHNOLOGIES TO THE MAXIMUM EXTENT PRACTICAL. . . .. 84
12.5 PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT . . .. 85
13.0 DOCUMENTATION OF SIGNIFICANT CHANGES. . . . . . . . . . . . . . . . .. 85.
14.0 RESULTS OF THE HAZARDOUS WASTE EVALUATION STUDY. . . . . .. 86
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NAS WHIDBEY ISLAND, OPERABLE UNIT 3
U. S. Navy - CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0074
Final Record of Decision'
Revision No.: 0
Date:' 03/29/95
Page v
Table
Table 6-1
Table 6-2
Table 7-1
Table 7-2
Table 7-3
Table 7-4
Table 7-5
Table 7-6
Table 7-7
Table 8-1
Table 8-2
Table 8-3
Table 8-4
TABLES
Page
Chemical-Specific ARARs Penaining to OU 3 , , , . . ~ . . . . . . . . .. . . 19
Chemicals of Concern at au 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . 20,
Human' Exposure Models Used to Evaluate Potential Risks
, from Chemicals at au 3 ., . . . . . . . . . . . , . , , , . . ; . . , . , , . . . . 32
SUuUnary of Potential Human Health Risks at au 3 .,.,..'........ 36
Overall Methodology for Ecological Risk Assessment. . . , . , . . . . . . . 45
Ecological Exposure Models Used to Evaluate Potential Risks
f~m Chemicals at OU 3 . ~ . , . : . . . . . , , , . ,', , . . ., . , ,'" . . . . .. 46
Su~mary of Ecological Risks in Soil. . . ',' . . . , , . , . . . . . . .. . . , 46
Summary of Ecological Risks in. Runway Ditch Sediments. . . . . . . . . . 48
, Summary of ECological Risks in Clover Valley Lagoon Sediments. . . . . 50
, Cleanup Levels for Runway Ditch Se.diments '.....,......,.,..,.. 61
, Comparison of TPH Concentr;itions in Ditch Sediments With
Bioassay and Benthic Community Assessment Results. . , .: . . . ',' . . . 63
Maximum Detected Concentrations at Runway Ditch Sediment Statjons .. 64
Exceedances of Cleanup Levels at Runway Ditch Sediment Stations. . . . . 66
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~AS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy - cLEAN Contract .
Engineering Field Activity. Northwest
Contract No. N62474-89-D-9295
CTO 0074
Final Record of Decision
Revision No.: 0
Date: 03/29/95
Page vi
FIGURES
Figure
Page.
Figure 2-1
NAS Whidbey Island Location' Map
. . . . . . . . . . . . . . . . . .
. . . . . .
2
Figure 2-2
Area 16 - Runway Ditches. . . . . ... . . . . . . . . . . . . . . . . . . . . . .. 4
Figure 6-1
Groundwater Flow Directions at Au1t Field. . . . . . . . . . . . . . . . . . .. 12
Figure 6-2
Groundwater Potentiometric Surface Contour Map - Runway Area ..... 13
Figure 6-3
Area 16 - Sampling Stations. . . . :'. . . .. .' . . . . . . . . . . . . . . . . . . 17
Figure 8-1
Ditch Segments SelectedJorRemediation . . . . . . . . . . : . . . . . . . . . . 67
Locations of Hazardous Waste Evaluation StlJdy Areas ...,..........87
. .
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NAS WHIDBEY ISLAND, OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0074
ABBREVIATIONS AND ACRONYMS
. Final Record of Decision'
Revision No.: 0
Date: 03/29/95
Page. vii
AOC - area of contamination
ARAR - applicable or relevant and appropriate requirement
bgs - below ground surface
CERCLA - Comprehensive Environmental Response, Compensation, and Liability Act
CPR - Code of Federal Regulations
COPC - ~hemical of potential concern .
. CSL - cleanup screening level
DNAPL - dense non-aqueous phase liquids
DoD - Department of Defense
Ecology - Washington State Department of Ecology
EF A Northwest -' Engineering Field Activity, Northwest
EP A - U.S. Environmental Protection Agency
FF A - Federal Facilities Agreement
FS ~ Feasibility Study "
FWQC - Fresh Water Qucility Criteria
FWQS - Fresh Water Quality Standard .
BEAST - Health Effects Assessment Summary Tables
HI - hazard Index
HPLC - high pressure liquid chromatograph
HQ - hazard quotient
IR - Installation Restoration
IRIS - Integrated Risk Information System
LDso - lethal dose for 50 percent of the exposed population
LOEL- lowest-observed-effects level'
MCL - maximum contaminant level
MSL - mean sea level'
MTCA - Model Toxies Control A<;:t .
NACIP - Navy Assessment and CQntrol of Installation Pollutants.
NOEL - no-observed-effects level'
NPL - National Priorities List
NUWC - Naval Undersea Warf~ Center
O&M - opera~ion and maintenance
OU - Operable Unit.
PAR - polynuclear aromatic hyd~n
. PCB - polychlorinated biphenyl
PGDN - propylene glycol dinitrate
PSAPCA - Puget Sound Air Pollution Control Agency
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NAS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
EngineeriIig Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0074
Final Record of Decision
Revision No.: 0
Date: 03/29/95
Page viii
RAB - Restoration Advisory Board
RAO - remedial action objective
. RCRA - Resource Conservation and Recovery Act
RID - reference dose (mg/kg-day)
RI - Remedial Investigation
RME - reasonable maximum exposure
ROD ":- Record of Decision
SARA - Superfund Amendments and Reauthorization Act
SF - slope factor (mg/kg-day)~1 .
SMS - Sediment Management Standards
SQS - sediment quality standard
SQV - sediment quality value
SVOC - semivolatile organic compound. .
, TCLP - toxicity characteristic leaching procedure
'TEC - toxicity equivalency concentration
TPH - total petroleum hydrocarbons
TRC - Technical Review Committee
TRV - toxicity reference value'
UCL - upper confidence limit.
VOC - volatile organic compound'
WAC - Washington Administrative Code
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NAS WHIDBEYISLA1iID. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
Engineering Field Activity. Northwest
Contract No. N62474-89-D-9295
CTO 0074
Final Record of Decision
Revision No.: 0
Date: 03/29/95"
Page "I
DECISION SUMMARY
1.0 INTRODUCTION
.In accordance with Executive Order 12580, the Comprehensive Environmental Response,
Compensation, and Liability Act of 1980 (CERCLA), as amended by the Superfund
Amendments and Reauthorization Act of 1986 (SARA), and, to the extent practicable, the
National Oil and Hazardous Substances Pollution Contingency Plan, the United States Navy
(Navy) is addressing environmental contamination at Naval Air Station (NAS) Whidbey
Island, Ault Field, by undertaking remedial action. The selected remedial aetion has the
approval of the United States 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 remedial actions will comply with applicable or "relevant" "
" and appropriate requirementS (ARARs) promulgated by Ecology, EPA, and other state and"
federal agencies. ""
2.0 SITE NAME, LOCATION, AND DESCRIPTION"
" "
NAS Whidbey Island, Ault Field, is located on Whidbey Island in Island County,
Washington, at the northern end of Puget Sound and the eastern end of the Strait of Juan de
. Fuca (Figure 2-1). The island is uriented nonh-south; w"ith a length of almost 40 'miles and a "
width varying from I to 10 miles. NAS Whidbey Island is located just north of the city of
Oak Harbor (population 14,000) and has two separate operations: Ault Field and the
Seaplane Base. ""
Ault Field is a Superfund site that has been divided into four separate operable units (OUs):
l, 2, 3, and 5. The Seaplane Base is a separately listed Superfund site and constitutes OU 4.
" .
This record of decision (ROD) addresses OU 3, which now consists only of Area 16. the
Runway Ditches. Area 31, the Fonner Runway Fire School, was initially included as pan of
OU 3. However, more information is needed and funher evaluation is necessary before a
remedial" action decision can b.e made for Area 31. Therefore, Area 31 has been removed
froin OU 3 and will be addressed as part of au 5.
This ROD also documents the decisions reached and the actions that will be taken as a result
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HAS Whldbey
(Ault Field)
Strait of
Juan de FUCII
'Area 31
STRAIT OF
JUAN DE FUCA
CRESCENT
, HARBoR
Sc:aJe in Miles
CLEAN
COMPREHENSIVE
LONG-TERM
ENVIRONMENTAL
ACTION NAVY
Figure 2.1
HAS Whidbey Island
Location Map
eTO 0074
OPERABLE UNIT 3
'NAS WHIDBEY, WA
RECORD OF DECISION
I
I
I
CT07MOO\FIG2_1,ORW 1/31/95
'"
~
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~AS WHIDBEY ISLAND. OPERABLE UNIT 3
, U.S. Navy - CLEAN Contract,
Engineering Field Activity. Northwest
Contract, No. N62474-89-D-9295
CTO 0074 '
Final Record of Decision
Revision No.: 0
Date: 03/29/95
Page 3
areas that had been originally identified at both Ault Field and the Seaplane Base but were
not included in OUs 1, 2, 3, or 4. '
Area, 16 comprises the eastern ponion of Ault Field! including the flightline area and 'the on-
site drainage areas through Clover Valley (Figure 2-2). Clover Valley Lagoon and Dugualla
Bay, which are east of the base boundary, 'were also included in the investigation because'
they are downgradient of Area 16.
The Ault Field Runway Ditches consist of approximately 9 miles of connected ditches and
1 mile of culvens that drain the runway area and receive discharge from many of the'
station's storm drains. The majority of the ditches eventually connec~ with the Clover Valley
'stream, which flows east toward the .Clover Valley Lagoon and Dugualla Bay (Figure 2-2).
, 'One ditch, located nonh of Runway 7-25, empties into the Strait of Juan de Fuca. This ditch
qnly receives runoff from the runway, not discharge from other stonn drains. Some of the
ditches do not contain water during the dO' season.,
, The bottoms of the ditches near the runway vary.in width from approximately 2 to 10 feet ..
and range in elevation from slightly below mean sea level 04SL) to 20 feet above MSL.
The banks of the ditches typically have a 30- to 45-degree slope and rise to a height of 5 to
10 feet above the base of the ditch'. Thick plant growth typical of wetlands is present in the
base of the flowing ditches. except where the water is greater than I foot deep. Sediment
buildup in the ditches is greater than 1 foot thick near storm drain discharges and is less than
6' inches in the ditches east of Runway 13-31. Until about 1981, the ditches were dredged '
with a dragline every 7 to 8 years. During dredging, sedim~nt was removed from the ditch,
base and reponedly placed along the, banks. Presently, there is little or no evidence of
dredged 'piles and the area is. thickly vegetated.
Three baffles have been installed along the runway ditches (Figure 2-2). The baffles are
intended to retain sediment and keep culvens from becoming clogged. ,The upstream
(westernmost) baffle,' south of Taxiway C, is constructed of.concrete; the two downstream
baffles are constructed of wood. , The upstream baffle is also constructed and operated to '
contain any floating petroleum product that may enter the ditches if a spill occurs on the
flightline., The upstream baffle used to have an oil/water separator with an electric, oil
, skimming recovery system that removed and containerized the floating product retained by
the baffle. The oil skimmer unit is now inoperable. Current practice at the base is to
immediately respond to spill events if and when they occur, with oil skimming perfonned as
, needed by a spill response contractor using a vacuum truck.
The Clover Valley Lagoon serves as a catchment basin for approximately 7,000 acres of land
drained by the ditch network. which includes most of Ault Field an~ some surrounding areas.
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t' . r . '\ i.;1'). "\ \.. ".,.,~~.. if >.~ . , ": :. ff ..:,""" ..A.. Navy Backup SupplyWeil
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/. ,i 'H'Hr"'H'''''.''''''\~4j '<'\.\18"'<... «"\.~JtE~~"~/' . ~~}5 ;.' i..~~./'. - - Major Dilch Channels
f"""""""-j'X' \:\ "',,/ ~ \ ,,~ :>.~.>'
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.:' 4 ~ 14 .;;'" \f:1\;HM""""!\""-"'''''w_,,,,,,w~ '.".W""W: ". I .
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.............................w.:./.......,.,,,,........,..,...., Ir:' ~ I J1""';'~~~ t~~)-:-.'-":.5 {:' 10: Ballle&OillWaterSeparalor
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'- --f 10. . . \. i' A. k',. .:ili,.~. J,
29' :' 1 . 7 8 ~..:.,/. . I '/..l':l<-. \ ':.~' ,.-"1, Base Boundary
.:~..:,:............:.:.:.....::.:.:::.L. G.iC'/<1f V"Ji9; RC3~ '. ...,.:.".".<0 .,,,,..:.~ .<:~:'\>" ~ ~;~:\::1";\ ~ Roads
,......., ".', ..:............... .,., >:-:.:.",w. .". "'"'0<''' ". W''''':'." ,.". :"':'I"::::~":~~"""N"'~''';;in;''''.7~'''''''~ \ "'.V".W.'...'.' ':r';"'O:""~::' ",. ~J..w.wm . ",,,,,,,.,,,,,,"".,.<"0'."
:' Ci1;}f!f!:; ~:.Jr~nr Heron .6 I + I 0 2000
NOTE: Operable Unill includes Areas 5 and 6. A"ent:a ~:>a,o. Rookery
Opamble Un~ 2 includes Areas 2. 3, 4, 14, and 29. SCALE IN FEET
I
"-
\.......
"""'. .,>~~~
.......,...,.,::~~.~v
CLEAN Agure 2.2 CTO 0074
COMPREHENSIVE Area 16. Runway Ditches - OPERABLE UNI13
LONG-TERM (Including adjacent areas of Investigation) NAS WHIDBEY. WA
ENVIRONMENTAL RECORD OF DECISION
ACTION NAVY
CT01AAOOfIG2.2.5 1113004
)
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- .
~AS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
Engineering Field Activity. Northwest
Contract No. N62474-89-D-9295
CTO 0074
Final Record of Decision
Revision No.: 0
Date: 03/29/95
Page 5
Discharge into the lagoon includes surface water from surrounding hills to th~ nonh and
south, wetlands in the southeastern ponion of the naval base, and surface water runoff
collected from Ault Field by the runway ditches and carried off base by the Clover Valley
. stream. Water flow in this stream was measured at 4.6 cubic. feet per second in June 199Z.
In the lower elevations :ofClover Valley, the stream system may interSect the water table and
receive groundwater input. The lagoon water surface is maintained at several feet below'
MSL by pumping water over a dike into Dugt1alIa Bay. Water from the uppermost ponion
of the lagoon is reponedly used to irrigate the surrounding agricultural fields; runoff from
these fields drains into the lagoon. Additional discussion about Clover Valley Lagoon and
Du~ Bay is included in secti
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NAS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract.
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0074
Final Record of Decision',
Revision No.: 0
Date: 03/29/95
Page 6
assigned to the Naval Facilities Engineering Command (NAVFACENGCOM). The
Southwest Division of NA VF ACENGCOM has responsibility for the western states.
Engineering Field Activity, Northwest" (BFA Northwest) has responsibility for investigations
at NASWhidbey Island and other naval installations in the Pacific Nonhwest and Alaska.
3.2 PREVIOUS INVESTIGATIONS AT NAS WHIDBEY ISLAND
The Navy conducted the Initial Assessment Study at NAS Whidbey Island under the NACIP
program in 1984 (SCS Engineers 1984). A more focused follow-up investigation and repon,
the NAS Whidbey Island Current Situation Repon, was completed in January 1988 (SCS .
Engineers 1988). After the Current Situation Report was completed, further investigations
were proposed for areas where contamination was verified and where unverified conditions
indicated funher investigations were appropriate. .
While the Current Situation Report was being prepared, EP A Region 10 perfonned .
p~liminary assessments at NAS Whidbey Island, Ault Field, to evaluate risks to p.ublic
health and the environment.using the HaZard Ranking System.
In late 1985,. EP A proposed that Ault Field be nominated for the National Priorities List
(NPL). In February 1990, the site was officially listed as a Superfund site on the NPL.
EP A's inclusion of Ault Field on the NPL was 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 potent.ial
for domestic wells and local shellfish beds. to be affected by wastes originating from the site.
, ..
As a result of the NPL listing, the Navy, EPA, and Ecology entered into a federal facility
agreement (FFA) in October 1990. The FFA estaplished a procedural framework arid
schedule for developing, implementing, and monitoring appropriate response actions at NAS
Whidbey Island. .
Following CERCLA and SARA guidelines, various sites and areas at NAS Whidbey Island
were later grouped into "operable units." . The tenn "operable unit"(OU) is used to .
designate. specific areas undergoing RIfFS investigations. The two areas at Ault Field, (Areas
16 and 3 J) were collectively identified as 'OU 3. An RIfFS for OU :3 'was conducted in
1992, with the Final RI report issued in January 1994(URS 1994a) and the Fined FS repon
issued in April 1994 (URS 1994b). The purpose of the RI/FS was to characterize the site,
determine the nature and extent of contamination, assess human and ecological risks, and
evaluate remedial alternatives. A proposed plan addressing the Navy'~ preference for
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- .
:-.lAS WHIDBEY ISLAND~ OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
. Engineering Field Activity, Northwest
Contract No. N62474:-89-D-9295
CTO 0074
. Final Record of Decision
. Revision No.: 0
Date: . 03/29/95
Page 7
4.0 COMMUNITY RELATIONS
The specific requirements for public participation pursuant to CERCLA Section 1 17(a), as'
amended by SARA, include releasing the proposed plan to the public. The proposed plan for
OU 3 (both' Areas 16 and 31) was issued on July 19, 1994, and an open house and public
meeting were held on July 26. 1994. . The public comment period expired on August 18,
1994. Approximately 30 comments were received on the proposed plan. The responsiveness
summary, that includes responses to comments, is included in this ROD as Appendix A.
As explained in Section 2, OU 3 no longer includes Area 31 (the Fonner Runway Fire
School). Therefore, Appendix A provides comments and responses only for Area 16 and
does not address public comments related to Area 31. Because Area 31 has been moved to .
OU 5, the comments and responses for this Area"will be provided in the responsiveness
summary sectio.n of the ROD for OU 5.' .
. .
Documents pertaining to this investigation were placed in the following infonnation
repositories:
Oak Harbor Library
7030 70th N. E.
9ak Harbor, Washington 98277
Phone: (360) 675-5115
Sno-Isle Regional Library System
. Coupevi~e Library
788 N.W'. Alexander
Coupeville. Washington 98239
Phone: (360) 678-4911
NAS Whidbey Island Library (for those with base access) .
1115 W. Lexington Street
. Oak Harbor, Washington 98278-2700
Phone: (360) 257-2702 '
. The Administrative Record is on file at the following location:
Engineering Field Activity, Northwest
. Naval Facilities En~eering Command
19917 7th Avenue
Poulsbo. Washington 98370
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NAS WHIDBEY ISLAND. OPERABLE UNIT 3
U ,S. Navy - CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0074
. Final Record of Decision'
Revision No.: 0
Date: 03/29/95
Page 8
Community relations activities have established communication between the citizens living. .
neaF the site, other interested organizations,' the Navy, EP A, and Ecology. The actions taken.
to satisfy the statutory requirements also provided a forum for citizen involvement and input
to the proposed plan and ROD. These have included: .
.
Creation of a. community relations plan.
.
Quaner~y Technical Review Committee (TRC) meetings with repres~ntatives
from the public and from other governmental agencies. .
.
. Monthly Restoration Advisory Board (RAB) meetings beginning February
1994 that replaced the TRC and provided additional public involvement in
O:U 3. . .
.
A public availability session, held in February 1994, where information was
presented to citizens about the ongo~ng environmental investigations .and the
Navy invited inte~sted persons to tour OU 3...' . . .
.
Issuance of a draft proposed plan for review and comment by the RAE
commi~ee on June 9, 1994, before the issuance of the f~al proposed plan.
Newspaper advenisement for the proposed plan and public meeting.
.
.
A public meeting on July 26. 1994, to present the fmdings of the OU 3 . .
investigations and to receive comments on the proposed plan.
In the National Defense Authonzation Act for Fiscal Year 1995 (Senate Bill 2182), SectIon
326(a), Assistance for PUblic Participation in Defense Environmental Restoration Activities,
the Department of Defense w~s directed to establish Restoration Advisory Boards (RABs) in
. lieu of Technical Review COD1mitt~s. In January 1994, NAS Whidbey Island became one
of the first Navy facilities to establish a RAB.
The purposes ~f the RAB are to:
'.
Act as a forum for discussion and exchange of information between the Navy,
regulatory agencies, ~d the community on environmental restoration topics.
.
. Provide an opponunity for stakeholders to review progress and panicipate in
the decisionmaking process by reviewing and commenting on actions and
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~AS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
Engineering Field Activity. Northwest
Contract No. N62474-89-D-9295
CTO 0074 .
Final Record of Decision
Revision No.: 0
Date: 03/29/95
Page 9
.
Serve as an outgrowth of the TRC concept by providing a more comprehensive.
forum for discussing environmental cleanup issues and serving as a mechanism
for RAB members to give advice as individuals. .
.. .
The RAB members consist of representatives from the Navy and regulatory agencies as well
as civic, private, city government. and environmental activist groups. The NAS Whidbey .
. Island RAB, as currently staffed, has a substantial representation from interested .
environmental organizations (Whidbey Island Preservationists, Whidbey Islanders fot a
Sound Environment, WJtidbey Island Audubon Society). .
The RAB has panicipated in development of the OU 3 decision documents. MembeI'$ were
. bri.efed on and reviewed two drafts of the proposed plan prior to the public meeting. The ..
RAB has also received draft review copies of this ROD and their comments were evaluated
for incorporation prior to this ROD being finalized.
5.0 SCOPE AND ROLE OF OPERABLE UNIT
Potential source areas at NAS Whidbey Island,. Ault Field, have been grouped into separate
OUs; for which different schedules have been established. Final cleanup actions for OUs 1
and 2 have been selected and RODs finalized. OU 5 is. proceeding through a focused
feasibility study with a ROD .scheduled to be final in 1995. For OU 4 (at the Seaplane
Base), the ROD was signed in 1993., and cleanup actions were completed in 1994.
The cleanup actions for OU 3 described in this ROD address only sediment contamination in
the Area 16 Runway Ditches. Ditch sediment is the only environmental medium requiring
active remediation. The cleanup actions described in this ROD address all known and
current and potential risks to human health and the environment associated with OU 3.
6.0 SUMl\.1ARY OF SITE CHARACTERISTICS
This section summarizes site conditions, including a discussion of the geologic, hydrologic.
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NAS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0074
Final Record of Decision.
Revision No.: 0
Date: 03/29/95
Page 10
6.1 PHYSICAL AND ENVIRONMENTAL SETTING
The following subsections discuss the geology, hydrogeology, surface water, and ecological
characteristics of au 3. ' ,
6.1.1 Geology and Hydrogeology
Whidbey Island lies within the Puget Sound Lowland, a topographic and struc~ra1 depression
between the Olympic Mountains and the Cascade Range. During the Quaternary Period (last
2 million years), the Puget Lowland was repeatedly covered by continental ice sheets
advancing from th~ north. Characteristic sedimentary deposits were formed during the
advance and retreat of these glaciers, as well as during interglacial periods. These glacial
and nonglacial deposits are up to several thousand feet deep on the island, but tend to be
thinner on the northern port~on of the island, including Ault Field, where bedrock is locally
exposed' at the surfaee. The near-surface deposits on the island were deposited during the
Fraser glaciation (20,000 to 10,000 years ago) and during the post-glacial period (10,000 '
years to the preSent). '
Features of the glacial/interglacial stratigraphy on northern' Whidbey Island and Ault Field
have been described from surficial exposures and boreholes during regional geologic studies
, , and site-:specific environmental investigations. The geologic units that have been identified at
OU 3 consist of the follo~ing, listed from youngest to oldest: .
.
,..
'.
.
.
.
.
Recent post glacial deposits: sand. silt, and clay with minor gravel and peat
Everson glaciomarine drift: silt and' clay with some sand, md minor gravel
. Vashon recessional outwash: 'sand and gravel with some silt
Vashontill: gravelly, sandy silt with some clay
Vashon advance outwash: clean to silty sand with some gravel and minor silt
Whidbey Fonnation: sand, silt, peat. and clay' . '
Double Bluff Drift: till, glaciomarine drift, and outwash
At Ault Field and surrounding areas, these geologic units locally rest on metamorphic
bedrock., The stratigraphic units at Area 16 consist of recent deposits overlying gfaciomarine
drift. which in turn overlies Vashon advance outwash deposits. Deposits of the Whidbey
Formation underlie the advance outwash. The Double Bluff Drift probably underlies the
. Whidbey Fonnation. The Whidbey Fonnation underlies the Vashon deposits.
The U.S. Geological Survey (USGS) has identified five major regional aquifers
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>JAS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy .: CLEAN Contract
- Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0074
Final Record of Decision
Revision No.: 0
Date: 03/29/95
Page 11
top. Individual aquifers may consist of one or more geologic units, and often there is not a
one-to-one correspondence between a particular aquifer and specific geological units over a
regional scale. The aquifers are generally composed of sand, or sand and gravel; aquitards
are composed mainly of n~nglacial clay and silt, glacial till, or glaciomarine drift. The
aquifer system at Whidbey Island is designated as.a so.e source aquifer, 'since it serves as the
only supply of potable water for at least half of the residents. there is no viable alternative
source of drinking water for those using groundwater, and the aquifer boundaries have been
defined.
Two aquifers have been identified at au 3. One is a local perched aquifer identified near
the northeast portion of the runways (around Area 31), but not identified at the Area 16 wells
in the southern portion of the runways. Th~ other is the regional aquifer corresponding to .
USGS bydrogeologic units C and D, forming a combined single aquifer at au 3 (USGS.
. Units C-D). This aquifer is laterally continuous throughout au 3 and much of Ault Field.
The localized perched water-bearing zones nonh of the runways occur above silt-rich . lenses
of Vashon -outwash and till. Measured water levels in these zones range from 0.5 to 4 feet
below ground surface (bgs) or 30 to 35 feet above MSL. The saturated thickness is
generally only a few feet. ~ow direction and velocity fOr the perched zones are .unknown.
The regional aquifer at au 3 occurs within fine to medium sand with some silt,
corresponding to the Vashon advance outwash and Whidbey Formation. No significant
aquitards were identified during drilling within either unit. This aquifer is confmed by the
overlying Everson glaciomarine silt and clay throughout much of the area. The regional
aquifer is at least 100 feet thick at au 3. Potentiometric groundwater levels in the southern
. portion of Area 16 range from about 5 feet bgs to 4 feet' above the ground surface (two
flowing artesian wells are located in this area); these levels correspond to elevations of 8 to
11 feet above MSL. .
Based on water level data from environmental investigations at NAS Whidbey Island and
from regional studies, it appears that groundwater flow at "!\ult Field generally follows
surface topography. The flow pattern for the uppennost regional aquifer at Ault Field
(USGS Units C-D) is illustrated in Figure 6-1. Most of the groundwater underlying Ault
Field converges in the central runway areas and like~y discharges eastward to Dugualla Bay.
Groundwater along the western side of Ault Field appears to discharge westward to the Strait
of Juan de Fuca. Water levels in three shallow wells in the southern portion of Area 16
suggest a generally northeastward flow, with groundwater converging from the west and
south (Figure 6-2). Groundwater in the northern portion of the runways flows south and
southwest.
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LEGEND
.
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. .
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16
18-28
Groundwater Divide for
Clover Valley (approx. location)
Topographic (Surlace Water)
Divide for CloYer Valley
Groundwater F.low Direction
(approximate)
Navy Backup Supply Well
NAS Whidbey Island
Investigation Areas
NOTE: Groundwaler divide location based on waler
levels in mon~oring wells and surface topography.
I+J
.... .
","',
CLEAN CTO 0074
Agure 6-1 OPERABLE UNIT 3
. COMPREHENSIVE Groundwater Row Directions at Ault Field NAS WHIDBEV;WA
LONG-TERM RECORD OF DECISION
ENVIRONMENTAL
ACTION NAVY
CTOlf11100HG6 )DRW tln4194
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CLEAN
COMPREHENSIVE
LONG-TERM
ENVIRONMENTAL
ACTION NAVY
Figure 6-2 .
Groundwater Potentiometric Surface Contour Map
Runway Area
CTO 0074
OPERABLE UNIT 3
NAS WHIDBEY, WA
I RECORD OF DECISION
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NAS Yt'HIDBEY ISLAND. OPERABLE UNIT 3
L S. Savy . CLEAN Contract .
Eop.oeenog Field Activity, Northwest
Coatr8C1 So. N62474-89-D-9295
era 0074
. , :,' '
Final Record of Decision'
Revision No.: 0
Date: 03/29/95
Page 14
The caJculated linear groundwater velocity for the southern part of Area 16 ranges from 13
to 300 feet per year, with an average of about 59 feet per year. Groundwater moving at this
average rate would take about 100 years to flow off site. .
6.1.2 Suriace Water
The Clover Valley Lagoon was created when a dik~ was constructed on the westem edge of
Dugualla Bay in 1915. Prior to dike construction, the region was a marine estuary, fonning
the extreme western reach of Dugualla Bay. In the western, riverineponion of the lagoon, it
appears that the agricultural fields were enlarged by partial filling of the estuarine headland".
The source of the fill was most likely material dredged from the river-estuary system. After
construction of the dike, runoff and sediment from the Clover Valley stream have collected
in the newly formed lagoon rather than being discharged outward into Dugualla Bay.
. .
. Although the Navy did not build the dike, the base maintains a pumping station that.
constantly pumps water from. the lagoon into Dugualla Bay, in order to prevent flooding of .
Ault Field and nearby lands. The water level in the lagoon area is reponedly maintained
. within a vertical range of 1 foot. However, the water level may be higher after heavy rains.
The maximum tidal fluctuation of Dugualla Bay is roughly 15 feet. .
There is an ab~nce of aquatic life in the bottom ponion of the lagoon. This condition was -
caused by physical changes that occulTed when the lagoon was initially formed by
construction of the dike, which interrupted the natural tidal flow in the original estuary. '.
Without tidal action, the water in the lagoon has become ~latively still, such that. the deeper
ponions do not readily mix with the upper surface water. B~use the bottom of the . lagoon
is below Dugual1a Bay tide levels, salt water enters the lagoon by seeping underneath the
dike and upward through the bottom sediments of the lagoon. The salinity of the lagoon.
water increases with depth, ranging up to 23 parts per thousand. .
Fresh water enters the lagoon from stonnwater drainage and stratifies on top of the salt
water. As a result of the stillness of the lagoon and the fact that salt water is denser than
fresh water, the salt water tends to stay at the bottom of the lagoon. -Because the salt water
in th~ deeper pan of the lagoon does not .mix with the f~sh water above, oxygen levels .have-
decreased in this deeper zone and in the bottom sediments. thus prohibiting the existence of
oxygen-demanding organisms. Bottom sediments in the lagoon consist of layered,
biologically undisturbed, dark gray to black silt and clay', which exhibit a hydrogen sulfide
odor and are rich in gaseous methane. TheSe sediment characteristics indicate anoxic (poorly
oxygenated) bottom conditions with high inputs of organic materials. Even though anoxic
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NAS WHIDBEY ISLAND. OPERABLE UNIT 3
. U.S. Navy - CLEAN Contract
, Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0074
Final Record of Decision
Revision No.: 0
Date: 03/29/95
Page 15
lagoon is a functioning ecosystem that suppons a large stickleback fish population, snails,
and migratory birds. '
6.1.3 Ecological Setting
A variety of habitat types exist at Ault Field, including mixed evergreen forests; brush 'and
grasslands; freshwatet wetlands; lagoon, beach, and coastal zones; and agricultural lands.
The largest ecosystems, in areal extent, are brush-grasslands and coniferous forests
(principally Douglas fir). Forested lands cover approximately 600 acres at Ault Field while
brush-grasslands encompass roughly 2,500 acres. Approximately 750 acres of land on the
Ault Field.propeny are leased for agricultural use and cultivated primarily for hay and grain.
The remainder of the base property is freshwater wetland or is covered by Navy structures.
Woodland and brosh-grassland areas provide habitat for deer, red fox, coyote, weasel,
rabbit, and smaller rodents. ,The wetlands suppon waterfowl and aquatic organisms .and
provide water for the ~er upland animals. Birds are common, most notab}y raptors,
upland game birds, waterfowl, and shore birds. Agricultural areas also provide feed and
cover for many birds.
Biota using the runway ditch complex include waterfowl and shore birds, mammals, fish,
invertebrates, and plants. Great blue herons are commonly observed foraging in the runway
,ditches. Ducks forage in the ditche$ and nest on the banks. Other species of water and .
shore birds are expeaect to periodically use the runway ditches for foraging. . Small mammals
. (e.g., voles and' shrews) periodically swim the ditches; muskrats 'have been observed in the
. ditches and presumably breed along the banks. Small fish (including three-spined
.sticklebacks) have been observed in the ditches. Invenebrare populations include snails,
leeches, insects, and small crUstaceans.
The riparian' habitat along the runway ditches and Clover Valley Lagoon provides nesting to
many bird species, including ducks, rails, coots, blackbirds, and kingfishers. Amphibians
that live in the aquatic and riparian habitat. Of the runway ditches and lagoon include frogs.
and salamanders. .
Dugualla Bay is ~ome to many species of flora and fauna that are typical of other inlets in
Puget Sound. Biological resources in Dugualla Bay include redrock and Dungeness crabs,
softshell and bent-nose clams, and a variety of ducks, gulls. and other shore birds.
Additional features in and near the bay that are important for biological resources include:
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. NAS WHIDBEY ISLAND, OP~LE UNIT 3
U.S. Navy - CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D~9295
CTO 0074
Final Record of Decision.
Revision No.: 0
Date: 03/29/95
Page 16 .
haul-out sites near the bay, spaw~g grounds for Pacific herring throughout the bay, and a
spawning beach for surf smelt on the south side of the bay. . .
Sensitive wildlife species that inhabit NAS Whidbey Island include the bald eagle, osprey,
great blue heron, peregrine falcon, and the Caspian tern. The bald eagle (a threatened
. sPecies) and the peregrine falcon (an endangered species) occasionally hunt near OU 3. A
bald eagle nest is located in the southwest area of Ault Field near Rocky Point. The bald
eagle and osprey also frequent the area just east of the dike, . attracted to .the perched hunti~g
. habitat provided by pilings. .
A great blue heron rookery with more than 30 nests is located on the southern border of Ault .
Field near the Charles Porter Avenue gate. Herons from the rookery heavily use the runway
ditches, Clover Valley Lagoon, and Dugualla Bay as foraging sites for fish and frogs:
6.2 NATURE AND EXTENT OF CONTAMINANTS
. .'.
Environmental media sampled during the OU 3 investigation inClude surface and subsurface'
soil, groundwater, ditch sediment, lagoon sediment, marine sediment, ditch surface water,
lagoon surface water, marine surface water. and marine shellfish tissue. LOcations of sample
collection points are shown in Figure 6-3. In general, the samples were analyzed for volatile
organic ~ompound~ (VOCs), semivolatile orgamc compounds (SVOCs), pe~ticides,
polychlorinated biphenyls (PCBs), chlorinated herbicides, total petroleum hydrocarbons
(TPH) and target analyte list (TAL) inorganics. VOCs and TPH analyses were not.
perfonned on the shellfish tissues. One of the .soil samples and one of the ditch sediment
samples were also analyzed for dibenzri-p-dioxins and dibenzo-p-furans. . Dioxinlfuran
analyses were not part of sampling scope d~veloped in the project work plans, but the
laboratory inadvenently analyzed these two samples along with other samples from another
site. . . . .
All of ~he chemicals detected a~ Area 16 were evaluated by a series of initial. screening steps
to identify chemicals of potential concern for each of the sampled media. Key steps in this
screening process included data validation to eliminate chemical results of inadequate quality,
comparison with risk-based screening values. and comparison with background
concentrations.' Details of the screenfng process are given in Section 7.1. L .
Chemicals not eliminated by the' initial screening steps were further evaluated to .determine .
chemicals of concern (COCs) for each sampied medium. COCs are defined as chemicals
detected at concentrations that exceed human health and ecological risk threshold
-------
, ,f' , \ (\~ ."" -.... ..;~,} ,,/~33 ~" ~"- '" ~'(j . /' /"tiIif.""'.'."'.." ." ",)6-39 ",,":,;)' ;"
/'~ '0.1', \\'\\~5~~~tf~':eI6-;'~ ,)It.......-- " ",.~0~f,,ut4"j;
//':"':'/ .../\--~;\\~~:~6-~6A&'ii'-"';;~:5'\>\\ . ./' i._e_U~.~~=:;;; lEGEND '." /.._~'
, ' ...... \ >.. .A" ,.:.i... ,.. . . " .._- :;
! l . ,.. .....--'>. \~ \. \ ",6-" ~ i! \. \~,.' / .
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'- .. . '" ,"'eo \.' " . So ~.
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J . w"". II \ I' ... m..,.,..
...,... . ~ \..r ,6-," , \~' ""'" ' . Sur1aceWalerSa
. '"'..''' I ' f I ~ ' I ' ....
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"'~"'; , ' " l' Ii '1' ..~. . ...... Sa
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-- -I - """"",,' 9 . " ..' . .' . ... ""~"" '
""~."..=.. "",,_...~ I """6-00, ." .. ,j:' ~'.' m,w,( '.' ,6-,,' ,~...~....... ...
, ~- '- "" . 31 ',)". . . .' -' - ."
-'.~" . . .. -'\' . I \..." . ......~C
,,".'. ", ..:,,:@);,~:..~:::: ,"" . 7\ "'<, ~... . \ .' .;'~ "on.... Colvelt hannels
" ,i;.. ; <, " ,!:::~,~........
Horon C".;;:;.,;e-" --- .~......"", .,1,< ...;....
, R Avl."~' ." --
ookery IOUli Giltli
CLEAN
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ACTION NAVY
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. ".-...;,;:-...;",'"
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....................
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o
2000
sCALE IN FEET I
CT00074
~ASPEAABlE UNIT 3
WHIDBEY
RECORD OF 0 . WA
, ECISION
Area 16 Agure 6-3,
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NAS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
Engineering Field Activity. Northwest
Contract No. N62474-89-D-9295
CTO 0074
. Final Record of Decision:
Revision No.: 0
Date: 03/29/95
Page 18
results or'the baseline risk assessment (Section 7) and by comparing maximum detected
concentrations to applicable or relevant arid. appropriate requirements (ARARs) of state and
federal regulations (Table 6-1). . Inorganic chemicals detected at or below background
concentrations are not considered COCs. Background' concentrations for inorganics were
established from samples collected at locations outside suspected areas of contamination.
. .
The following paragraphs' describe the nature and extent of contamination for the COCs . that
were identified in soil, groundwater, surface water, sediment, and shellfish tissues for Area'
'16. Table 6-2 provides a summary of the COCs identified for Area 16, including the range
of detected concentrations, the frequency of detection, and the calculated background values
for comparison. .
6.2.1 Soil
Soil sampled at Area 16 included soil borings near the runway ditches and soil collected from
the ditch banks. Both surface and subsurface. samples were collected from the soil borings.
Only surface soil samples were collecJed from the ditch bank. The ditch bank samples were
. taken from the crest of the bank, where dredged sediments may have been piled' from past
dredging activity, as well as midway up the bank slope. In addition, surface soil samples
we~ taken at several locations away from the immediate vicinity of the' ditch banks.
Arsenic, beryllium, and manganese were identified as COCs in both surface and subsurface
soils at Area 16. However, they do not form any clear distribution panern and are not.
associated with any obvious sources. These inorganic chemicals occur naturally in soil.
Dioxin (2,3,7,8~TCDD), selenium, and total petroleum hydrocarbons were identified as"
COCs in surface soil. Dioxin was detected at the only station sampled (16-26), located in
the central flightline area. Petroleum hydrocarbons were identified'as COCs at three widely
. spaced stations, with the highest concentration near the fljghtline area (station 16-4).
Although dioxin and selenium were identified as ecological risk contributors, the conclusion
of the baseline risk assessment was that minimal impacts to dit~h bank organisms from COCs
are expected.
6.2.Z Groundwater
Arsenic and manganese were identified as COCs' in groundwater based on several
exceedances of drinking water ARARs. Concentrations of arsenic and manganese were
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NAS WHIDBEY ISLAND, OPERABLE UNIT 3
lJ. S. Navy. CLEAN Contract.
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0074
Final R~cord of D~cision
Revision No.: 0
Date: 03/29/95
Page 19
Table 6-1
Chemical-Specific ARARs Pertaining to OU 3
Soil
Dilch Sediment
"_."..Ii
.
Lagoon Sediment
Dugualla Bay Sediment
Ditch Water
Lagoon Water
Groundwater
.
.
.
.
.
.
.
.
.
.
.
DuguaUa Oay
Sheillish Tissne
ARAR
.
= applicable. or relevant and appropriate requirement
= requirement ia considered an ARAR
CITATIONS:
I. Washington sediment management standards: 173 WAC 204.
2. Washington fresh waler qualily slandards: Washinglon Water Pollulion COnlrol Act: 90.48 RCW; 173 WAC. 20 I A.
3. Federal fresh water qualily crileria: Clean Waler Acl (Federal Waler poliulion Conlro' Acl, 33 USC 1251-1387; CWA 303-304)-
4. Federal drinking waler standards: Safe Drinking Water ACI, 42 use 300; 40 CFR 141. 143.
5. W..hinglon drin~inll waler 8tlnda.d8: Siale Ooard of llealth Drin~ing Waler Regulaliona, 246 WAC 290.
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NAS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
Engineering Field Activity. Northwest
Contract No. N62474-89-D-9295
CTO 0074
Final Record of Decision:~
Revision No.: 0
Date: 03/29/95
Page 20
Table 6-2
Cbemicals of Concern at OU 3
liP !-'I-!II_ll~.i:t;il
S9i1.Surf.Ke{aiiti.Jijt:\Hi .......'<' .','.,,'. ,',""< """'<'. H ,," 'H' H H' H" 'H"'''' ":"W':w,//,m://\Wm:t:' ,,"".,.' "'",:.,:.,.,'.".':"
7/41 0.19 3.2
14/45 0.0049 .0.61
4/44 0.0048 0.095
4/40 0.36 2.3
7/40 0.14 12.0
6/45 0.19 0.77
6/45 0.014 1.2
37/45 4,1 581
8/41 0.63 15.0
9/41 0.89 4,9
7/40 0.38 3.3
6/41 0.72 13.0
Arsenic
7.5
0.5
681
Beryllium
Manganese
Gro.dwa":(II&:IQi:m
Arsenic
. '..
.....
Manganese
'~:'WUei'..:DitdI:,:(jigI~l..'::
Copper
Lead
10
4
Mercury
Silver
SediiDeat,:Dittb{liijjlq}.,,)
2-Methyl~phtha1ene
4.4'-DDD
4,4'-DDT
H'
Acenaphthene
Anthracene
AToc:1or-1254
AToc:lor-1260
Arsenic
BenzolaJanthracene
3.4
Benzolb )flu,oranthehe
Benzo(g ,h. i)perylene
Benzol k)fluoranthene
6/26
17/26
7/26
. .....
I'
I
9/9
9/9
"".
....
MTCA
MTCA
MTCA
.
MTCA
8.2
0.53
686
H :'".',':' ,':': "...,.',';
65.9
0.87
763
MTCA
MTCA
MTCA
~
H
",.,
2.8
207
12.8
1.640
MTCA
MTCA
H , ',. :""",.'"",:,:::
EPA FWQC (C)
EPA FWQC (C)
W A FWQS (A)
EPA FWQC (A)
....
........... """,-...
,',,",'.'.",..".',",'.'.""'.','.'.'.",.
. ........... ........
...........""',,,,,,,
"""'''''..-.......
......................
.. "'"''''''''''''''
....... .. ................ ........
. . .... "" .
. ...
"
...... .
.....
... . ...
"
.
.
.
.
.
.
.
.
.
.
'.
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NAS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0074
Final Record of Decision
Revision No.: 0
Date: 03/29/95
Page 21
Table 6-2 (Continued)
Chemicals of Concern at OU 3
L-
Dibenz(a.h)anthncene 5140 0.32 1.9 .
Dimethylphilwate 7140 017 17.0 .
Endosulfan 1 2/45 0.0051 0.0073 .
FelUl,llfothion 2/45 0.2 0.27 .
Fluorene 7145 0.077 5.4 .
Lead 18 2\145 24.0 942 .
Methyl azinphoa (Guthion) 7145 0.32 1.7 .
Phenanthrene 8141 0.33 20.0 .
Pyrene13/43 0.46 52.0
TPH 26/45 27 123.000
Zinc 87 32/45 91.0 2,100 .
'$.fI<;~';ti11811.,f~:~!:~.#iI"i.tf};rm;:;t:::~?r;:(~;:;;;;;;:~;:::::::;:r:m:m:m:mtr;?}:@:@:;;:::?@;::;:;;:~@;;(?:Hi\:HH::=:{m:(m~;:;:;rtb:
Cadmium \.8 6/6 4.1 7.6 .
Nickel 63 6/6 133 233 .
-
Selenium 1.0 1/6 \.4 \.4 .
Thallium 0.3 4/6 0.32 I.S .
Vanadium S6 4/6 59.4 121 .
Zinc 104 6/6 244 517 .
~';:oeep:;pOitiOi.).f:;J~I~;:~rii ..."'" .. . ':...:"" ..... ..;:~:\:::;:;;;:::::})g:';/:\itt\;;;:;:();
.
MTCA'
::.:::::;.::.::::::::::.~'..,
.....
Dieldrin 2/10 0.0032 0.0042 .
Dimethoate 2/4 0.0023 0..0027 .
Nickel 63 8/8 102 143 .
Thallium 0.3 1/8 1.0 1.0 .
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NAS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0074
Final Record of Decision
Revision No.: 0
Date: 03/29/95
Page 22
Table 6-2 (Continued)
Chemicals of Concern at OU 3
FOOTNOTES:
a The first number in eacli cell.is the number of detections above background: for chemicals with no background value,
the number of detections above background eqwils the total number of detections. The second number in each cell is the
total number of samples analyzed.
b For human health risk, if combined cancer risk is greater than 10-4, a major risk: collll'ibutor is a chemical in a medium
that conaibutes greater than .10.5 to the total risk. For noncancerrisks with an HI greater than 1.0. a major risk
conaibutor is a chemical in a medium that collll'ibutes an HQ greater than 0.1. . .
For ecological risk, a chemical that collll'ibutes an. HQ greater than I is a major risk contributor.
~ Exceeds the MTCA Method A value for soil, which is not deemed an ARAR for sediments but has been included here as
guidance "to be consjdered" (TBC); for further discussion, see Seclion 8.1.3. 0
ABBREVIATIONS:
ARAR = applicable or relevant and appropriate requirement.
MCL = Federal Safe Drinking Water Act (42 USC 300) Maximum Contaminant Levels (40 CFR 141).
MTCA . . =:= Model Toxics Control Act cleanup levels. 0 0
EPA FWQC (A & C) = Clean Water Act (Federal Water Pollution Control Act, 33 USC 1251-1387; CWA 303-304),
Fresh Water Quality Criteria (Acute and Chronic). 0
oW A FWQS (A & C) = Washington Water Pollution Control Act (90.48 RCW), Fresh Water Quality Standards (Acute &.
Chronic) (WAC 173-201A). 0 0 0
= Toxicity Equivalency Concentration (individual dioxinslfurans concentralions were converted to
equivalent 2.3,7,8-TCDD concentralion using EPA's toxicity" equivalency factors).
= total petroleum hydrocarbons.
TEC
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,~AS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
Engineering Field Activity. Northwest
Contract No. N62474-89-D-9295
CTO 0074
Final Record of Decision
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Page 23
for all wells at Area 16, both shallow and deep. Arsenic and manganese occur naturally in
groundwater at variable concentrations. Because these chemicals occur in background soils,
and the groundwater samples used to establish background concentrations were silty,
representative background concentrations for the site, are not available:. Ho'wever, the results
for the wells at 'Area 16 were not unusual compared with tyPical regional conditions.
. ,
In addition to the chemicals of concern listed in Table 6-2, two chlorinated herbicides
(dinoseb and 2,4-D) were also detected in the Area 16 groundwater samples from Phase I of '
the investigation. These herbicides have apparently been used throughout the base and in
other nearby agricultural areas. ~owever, it is unlikely that chemicals have migrated from
the Area 16 runway ditches into the groundwater because of the presence of a silt 'aquitard at
the ground surface and upward hydraulic gradients from the confined aquifer just below the
aquitard (the shallowest groundwater at Area 16 is in this conrmed aquifer). '
The, Phase I dinoseb results exceeded the drinking water standard for two stiaJIow wells and
one deeP well. The Phase I results for 2,4-D also -exceeded the'drinking water standatd for'
one of these shallow wells. However, these herbicides are not considered to be chemicals of
concern for the followmg reasons. . There were laboratory 'interferences associated with
almost all of the Phase I dinoseb and 2,4-D results, particularly all the results that exceeded
drinking water standards. The gas chromatograms (GC) for these analyses exhibited
saturated peaks that interfered with the detection and quantitation of the target compounds
(i.e., dinoseb and 2,4-D) and caused disagreement between the analytical results for the two
GC columns. These interferences appear to be due to co-eluting compounds and make the
results for the Phase I dinoseb and 2,4-D analyses suspect. . Because of these interferences
, and questionable ,results, two' of the wells were, resampled and reanalyzed for herbi6ides in
Phase n, including the well whiCh exhibited the highest concentrations of dinoseb and 2,4-D
in Phase 1. Neither chemical was detected in the Phase n samples, with detection limits well '
below the drinking water standards. The interference problems experienced in Phase I did
oot occur in the Phase II analyses. Because of the questionable results for Phase I and the
lack of detections with no interferences in Phase II, the Phase I results for dinoseb and 2,4-D
are considered to be anomalous.
6.2.3 Surface Water
Copper, lead, mercury, and silver were identified as COCs in ditch surface water at some
'stations, but at a very low frequency (Table 6-2). Three of these metals were detected at one
station located adjacent to the heron rookery (station 16-31). Two other stations with
detections were upstream of the base industrial area. One of the metals was also detected at
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NAS \\'HIDBEY ISLAND. OPERABLE UNIT 3
U.S. ~avy . CLEAN Contract.
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COOU'8Ct No. N62474-89-D-9295
CTO 0074 .
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6.2.4 Runway Ditch Sediment
No ARARs currently exist t.hat apply to freshwater sediments. Numerous chemicals detected
in the ditch sediments were identified as COCs because of their significant contributions to
ecological risk. The following chemicals were identified as COCs in . the runway ditches:
.
.
Metals (arsenic, lead, zinc) . . .. .
Semivolatile organic compounds (SVOCs) including many polynuclear
aromatic hydrocarbons (PAHs) .
Pesticides (DDD, DDT, endosulfan, fensulfothiori, methyl azinphos)
Polychlorinated biphenyls (PCBs [aroclors]) .
.
.
One or more of these COCs were found at a varie~y of the sample stations located throughout
the 'runway ditch complex. Stations with the highest concentrations included three in the
flightline core area (16-4, 16-6, and 16-7) and two at the eastern end of the runways in the
ditches that lead to the Clover Valley stream (16-11 and 16-35). Stations 16-~ and 16:-11 are
located behind' baffles, where sediment and chemical aCcumulations would be expected.
Most of the SVOCs and pesticides were identified at station 16-4, which is located directly
downstream of a storm sewer outfall from the industrial part of the base along the flightline.
A number of SVOCs were also identified at station 16-35 located. at the east end of runways;
Navy pilots perfonn "touch and go" flight training operations' at this part of the runways,
. . which may'res4lt in increased jet engine emissions and might affect this part of the base.
Some station's where COCs were identified are upstream of the runway complex. such as .
station .16-31 near the southern boundary of the base. .
, .
In general, the. concentrations of chemicals in ditch sediment were found to decrease with
depth. The overall distribution pattern suggests that the runways and industrial part of the
base were the sources of these chemicals, and .they have reached the ditches via the stonn .
sewers. In addition, an upstream source is suspected' to explain detections in the ditch near
the southern boundary of Ault Field. The .pesticides found at many of the stations likely
originated from past on- and off-site surface applications.
The I.U data were evaluated to determine if the ditch sediments meet the criteria for
designation as a hazardous waste as defined in hazardous waste regulations. Since the
sediments do not display the characteristics of ignitability, corrosivity, or reactivity, the
assessment of the toxicity characteristic was used determine whether or not the soil meets the
hazardous waste criteria. Nonnally, this evaluation is done by analyzing samples for toxicity
characteristic leaching procedure (TCLP) constitUents (40 CFR 261.24). Because YCLP
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constituents detected in the sediment samples were compared with the TCLP criteria, with
adjustment by a factor of 20 because a 20-fold dilution occurs in the TCLP test. In general,
this evaluation showed that the concentJ;ations of COPCs detected in the RI ditch sediment
. samples were below hazardous waste designation levels. .
6.2.5 Clover Valley ~goon Surface Water and Sediment.
. No metals or organic compounds exceeding federal or state surface water quality standards
(acute ~d chronic criteria for freshwater aquatic organisms) were detected at any surface
water sampling station in the Clover Valley Lagoon.
Seyeral metals and organic compounds were identified as COCs in the shallow and deep
sediments of the lagoon (Table 6-2), based on the muskrat exposure modeling and sediment
quality value comparisons conducted in the ecological risk assessment. However, the hazard .
quotients were low, many of the COCs were inorganics that represent little risk compared
with background conditions, and the ecological risk assessment concluded that adverse effects
from the chemicals detected in the. sediments are unlikely. . The bioassay test resul~s for
lagoon sediments confmned a low potential for ecological impacts, as all but one of the tests
passed the state sediment quality standards and all the results met the state sediment cleanup
screening levels.
In addition to the chemicals listed in Table 6-2, the ecologic3I risk assessment also idtmtified
acetone in sediments as posing risk to organisms in the. lagoon. However.. the . risk for.
acetone is likely .a laboratory artifact because acetone is a common laboratory chemical and
the risk estiMate for acetone was elevated by inclusion of high detection limits in the risk
calculations for samples where acetone was not detected. . For samples in which acetone was
actually detected, the concentrations were below levels of concern. for ecological risk.
Because of this, acetone in lagoon sediments is not considered to be a chemical of concern
even though it was carried forward and included in the ecological risk calculations.
The chemicals detected in the lagoon probably came from the Navy's operations at Ault Fielct
via. the runway ditches, as well as from other non-Na.vy sources. The RI sampling stations
were distributed throughout the ditch complex in order to define the contributions and
interrelationships among the various segments to the overall chemical load carried through
the system to the lagoon. This includes contributions from upgradient and off-base sou~es
captured in the ditch complex and carried through the Clover Valley drainage system.
Surface water flow and sediment entrainment are the primary mechanisms by which' COCs in
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U.S. Navy - CLEAN Contract .
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
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Final Record of Decision.
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Date: 03/29/95
Page 26 '
fine-grained organic material in the sedim~nt panicles. During stonn events when water
flows increase in the ditches, thesepaniculates can become temporarily suspended and move
with the ditch water. . When flows subside, the paniculates can drop out of suspension and be
deposited farther downstream in the ditch channel. Deposited material can be resuspended
when more water is flowing in the ditch or can be covered by additional deposits, which'
. prevent future mobilization.
Ifthe particulates reach a quiet water body such as the Clover Valley Lagoon, the
particulates will tend to settle to its bottom. Once deposited in the lagoon, the bottom
sediments will not likely become resuspended because no tidal currents influence the lagoon.
and because wind-driven currents diminish with depth and become negligible near the bottom
of the lagoon.
, .
The RI data for sediments in the ditch network, and the lagoon indicate that the -majority of
the sediment-bound contamination that originated 'from the Navy s~onn sewers has tended to
remain relatively close to the flightline and runway source areas, rather than migrating far
along the ditches and impacting the lagoon. These data' show that, under curren~ conditions,.
concentrations of chemicals found in the ditch sediments generally decrease as the sampling
stations move away from the runways and downstream toward the lagoon. The baffles in the
ditches appear to have impeded sew.mcmt transport and limited the potential for contaminants
to migrate into the lagoon. . .
In addition, increased concentrations were obselVed at sample stations near roadways along
the ditch, the Clover Valley stream. and/or the lagoon itself. These results indicate that
sources other than Ault Field have probably also contributed to the chemicals found in the
Clover Valley Lagoon. . The lagoon is surrounded by agricultural fields and private' .
landowners that may contribute to the hydrocarbon and pesticide concentrations found in the
lagoon. Several off-site ditches also drain into the lagoon or ttie stream that feeds the lagoon
(Figure 2-2). The ,roadway ditch along Hoffman 'Road discharges to the ditch at station,
16-11, upstream of the lagoon. In addition, Highway 20 is located near the western border
of the lagoon and its drainage goes into the lagoon. These roadways are suspected of haviJ:'lg
contributed to the chemicals in the lagoon (in addition to inputs from the Navy's activities)
because the chemicals found in the lagoon are similar to the types found in urban runoff. '
Runoff from agricultural lands and roads are expected to remain as ongoing sources of .
chemical inputs to the lagoon.. , . , ..
Some of the chemicals detected'in the ditch sediments were also detected in the lagoon.
sediments. 'but at much lower concentrations. All the organic chemicals detected in samples
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Fmal Record of Decision
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samples collected from the lagoon. Results for metals followed a more erratic pattern, but
generally also decreased in concentration with distance from the central flightline area.
Section 7 of the RI Report presents a series of graphs illustrating these general trends. These.
. graphs plot the chemical concentrations in sediment samples in the order of increasing
distance from the main on;.sitesource area .at ttIe sewer discharges near the flightliIie (i.e.,
. station 16-4) through the remairider ofthe ditch network toward the lagoon. The following
subsections summarize the trends depicted in the RI plots for different classes of chemicals.
. Inorganic Chemicals
The plots for cadmium, lead, nickel, and zinc showed decreasing concentrations with
increasing distance from the main sewer discharge..area (station 16-4). Each chemical also
exhibited an expected high at stations 16-35 (east end of the runway) and 16-11 (roadway
ditch and baffle). The current source of lead probably originates from automobile activity on
.. Highway 20. Mercury was only detected in two samples of lagoon sediment. The
concentrations detected were low, near the detection limits. Arsenic was fairly consistent in
concentration along the ditches except for an abnormally high level at station 16-35; this is
most likely due to NAS activities: .
. Semivolatile Organic Compounds
Graphs of chemical concentration versus distance from the flightline sewer discharge for
2-methylnaphthalene, dimethylphthalate, and phenol showed that concentrations decreased .
markedly with dis~ce from the cen~ flightline area. Phenol concentration roSe at .station
16-12 (near the highway and downstream of the runways), indicating possible additional
inputs from non-Navy sources. .
. Polynuclear Aromatic Hydrocarbons (PADs)
Graphs of chemical concentratio.n versus distance from the flightline discharge points for
PAHs (acenaphthene. anthracene, fluorene. and phenanthrene, benzo[a]anthracene,
benzo[b ]fluoranthene. benzo[g, h,i]perylene. benzo[k]fluoran1Qene. dibenz[ a, h ] anthracene, and
pyrene) showed a general decreasing trend in concentration from the sewer discharge at the
. flightline to the lagoon. Several of these graphs also showed an expected spike in
concentration at station 16-35, most likely due to NAS training exercises. There was a
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. Pesticides and Polychlorinated Biphenyls (PCBs)
"" ,
Graphs of chemical concentration versus distance from the flightline sewer area for pesticid~s
(methyl azinphos, 4,4-DDD, 4,4-DDT, and Endosulfan I) and PCBs (Aroclor-1254 and .
Aroclor-1260) showed a general trend of markedly decreasing concentration with distance
from the flightline. .
The Aro<;lor-1254 plot also showed higher concentrations at statio~s 16-11 and 16-~5, most
"likely due to NAS operations and the presence of the baffle. There was a substantial
decrease in concentration from stations 16-11 and 16-35 to station 16-12 located upstream of
the lagoon. The concentrations near the entrance to the lagoon showed a slight increase,
possibly indicating an additional (non-Navy) source. The pesticide/PCB plots had the same
characteristic shape as .exhibited in the plots for PAHs.
. Total Petroleum Hydrocarbons" (TPH)
TPH concentrations showed a decrease in concentration versus increased distB.nce from the
central flightline stations. The TPH plots showed a sharp spike at station 16-11, which may'
be due in part to runoff from Hoffman Road. This station is also located just upst~ from
a baffle, so hydrocarbons resulting from the naval flightline operations may also have
accumulated at this point. TPH dropped to a very low concentration downstream of this
baffle, at station 16-12 which is prior to Highway 20. .
Relatively high concentrations of TPH were found in the surface sediments at stations 16-13
and 16-14. .The TPH at these stations most 'likely resulted from Highway 20 runoff.
6.2.6 Dugualla Bay Sediment and Clam Tissue
No COCs were identified' for sedir.nent in" Dugualla Bay. Some Qf the chemicals detected in
sediment from the Clover Valley Lagoon were also detected in Dugualla Bay. Arsenic.
cadmium. lead, and total petroleum hydrocarbons were detected in both Clover Valley
Lagoon and Duguana Bay sediments, but were at lower concentrations in the bay than. in the
lagoon sedime~ts and showed no obvious distribution pattern in Dugualla Bay.
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7.0 SUMMARY OF SITE RISKS
A baseline risk assessment (RA) was conducted to. analyze both current and potential future
risks for au 3. It serves as a baseline to indicate what risks could exist if no action were
taken, taking into 'consideration possible risks if existing land use patterns were to shift in the
future to other uses, such as residential or full-time industrial activity. The risk assessment"
, results are used in evalUating whether remedial action is needed. The primary components of
the risk assessment are ,chemical, screening to identify chemicals of potential concern,
exposure assessment, toxicity assessment, and ris~ characterization.
, ,BQth human health and ecological'risk assessments were conducted as part of the
inv~stigation for au 3 at NAS Whidbey Island. A summary of the RA procedures and
fmdings is presented in this section'.
7.1 HUMAN HEALTH RISK ASSESSMENT
The human health RA evaluated potential risks associated with exposure to chemical
contaminants detected at au 3. Risks were calculated for,three exposure scenarios: current
on-site workers, recreatiorial'visitors, and future residents.
7.1.1 ,Chemical Screening
The chemical results obtained for the RI samples at au 3 were evaluated by a nU,mOOr of '
initial screening steps to identify chemicals of potential concern (COPCs). These COPCs
were carried through the remainder of the risk assessment to quantify risks at OU 3 and
determine the chemicals that contribute most significantly to overall site risks. The most
, significanfrisk-contributing chemicals are discussed as chemicals of concern (COCs) in
Section 6.2. '
The chemi~ ,screening steps used to establish COPCs included:
.
Sample grouping. For each environmental medium, samples were selectecHtw
are most representative for a particular exposure pathway. For example.
chemical results for soil samples collected in the upper 2 feet of soil were used
for -current human exposures. whereas samples from the upper 15 feet of soil
, were used for future exposures because deeper soil might be brought to the
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.
Dala validation. The quality of the data was evaluated. in accordance with
EPA guidelines, to assess whether each chemical result was suitable for use in
the risk asseSsment. Data rejected for inadequate quality were not carried
forward in the quantitative risk assessment.
.
Nonderecred chemicals. If a chemical was not detected in any of the samples
for a particular medium,. the chemical was screened out of the risk assessment.
, .
' .
.
Essenrial nUtriems. Certain inorganic chemicals were not included in the risk
. calculations because they are essential nutrients that are either nontoxic or
toxic only at high concentrations. This screening is in accord with EPA
guidance which approves of eliminating such nutrients frorn the human health
risk assessment.
.
Toxiciry. The maximum detected concentrations in each medium were
compared with risk-based screening concentrations developed by EPA Region
10. For chemicals in water, the screening concentration designated by EPA
represents a 10-6 risk level for cancer effects, and a hazard quotient (HQ) of
0.1 for noncancer effects. For soil or sediment; the screening concentration
was equivalent to a 10-7 cancer risk and an HQ of 0.1. These screening.
concentrations represent conservative risk levels, so that significant risk-
causing chemicals will not be screened out. (See Section 7.1.3 for
,explanation~ of hazard quotient and cancer risk levels.)
.
Background. Inorganic chemicals that were not eliminated during the above
screening steps were compared with background. concentrations to determine if
they are present on,site at elevated levels. Background data for inorganics
were used t<;> screen on-site chemicals because inorganics are na~rally ,
occuiring and ubiquitous. Background screening was not conducted for any
organic chemicals. Several different methods were used for the backgrol,1nd
screening, depending on the number of sample results available for a given
comparison: details are given in Section 6.2.1 of the RI Report.
All chemicals that still remained as COPCs following the chemical screening were evaluated
in the quantitative risk assessment. . . , ,
7.1.2 Exposure Assessment
The purpose of the exposure assessment was to quantify.contact with chemicals of potential .
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potentially 'exposed populations (ba~ed on CUITent and future land uses), and the routes of
exposure; and by quantifying human intake of chemicals for these media. populations, and
routes. A summary of the exposures that were evaluated is presented in Table 7-1.
Potentially exposed populations (receptors) and exposure routes (pathways) were identified
for CUITent and potential future land uses for each of three s~bareas evaluated in the human
health risk assessment: the runway ditches, Clover Valley' Lagoon, and Dugualla Bay. The
populations that were considered include on-site workers, reCreational visitors, and future
residents. Pathways pertinent to each subarea, population, and medium are identified in .
Table. 7-1. .
. In order to calculate human intake of chemicals, exposure point concentrations must be
estimated. Exposure-point concentrations are those concentrations of each chemical to which
an individual may potentially be exposed for each medium at tbe site. Exposure-point
concentrations were developed from analytical data obtained during the investigation. '
Exposure point concentrations were calculated for both.an average exposure and a reasonable
maximum exposure (RME). The' RME corresponds to the highest plausible degree of .
exposure that may be anticipated for a site. The RME concentration is designed to be higher
than the concentration that will be experienced by most individuals in an exposed population. '
. The RME' concentration was calculated as the le~ser of the maximum detected concentration
or the 95 percent confidence limit on the arithmetic mean. '
The. average exposure scenario was evaluated to allow a comparison with the RME. The
'average scenario is intended to be more' representative oflikely human exposures at the site.
The average exposure point concentrations were calculated as an arithmetic average of the
chemical results for a particular medium.
In calculating exposure point concentrations, a value of one-half the sample quantitation limit
was generally used for samples in which a panicular cheQllca1 was n~t detected. This
procedure is designed to avoid underestimating risks. To avoid overestimation, this
procedure was not applied' to samples with abnonnally high quantitation limits. The '
approach used to screen unusually high detection limit data from the quantitative risk'
asSessment consisted of first identifying detection limits that were elevated substantially
above the typical detection limits for a given analyte and medium, and then eliminating those
data with detection limits that exceeded the highest detected concentration by an order of
magnitude or more. This approach eliminated few samples from the data set and provided
more ~istic exposure point concentrations. "
'Estimates of potential human intake of chemicals for each exposure pathway were calculated
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Table 7-1
Human' Exposure Models Selected to Evaluate Potential
Risks from Chemicals at OU J
""".....,"""-"",, .
~~i¥~~~f .:::{(#'!H.(QiHH~::W~i!¥)ft::::::\ . ... .."'. .~~fi:,~~,::!r:::::t::::::t:::::::::\'rfl~HiJ~WiiWy.m~~:::::::::::{::{:::r
.... .,..~iiili(:.JNq. ... ::::imW\::::: .<:Jpq?::t mq... .rnmr/:/r:::f:pq':/'Jff9.\:{: pp'.nm:/.r .iP9:
Soil . . . . . .
Sedimenl. .. .
Surface waler . .
Groundwaler . . .
Fish/shellfish
.
.
.
tNO
INH
DC
= ingeslion
= inhalalion
= derlJ1al conlacl
final Record of Decision
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:f:::,::::::::::r:/jffrJ8iiQi:fiSf(:r::rrff::::r::j:
!!i:JJ!:!:!~ij~:JJ'J:!~=i~=.1
.
.
.
.
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parameters such as ingestion rate, body weight, exposure frequency, and exposure duration)
for each' medium of concern. Exposure parameters used in the risk assessment calculations
were based on a combination of EPA Region 10 default values.(U.S. EPA 1991) and site-
specific exposure assumptions; specific values can be found in Table 6-25 Of the RI Repon.
More conservative exposure parameters were used to calcuiate RME chemical intakes than
were used to calculate average intakes. '. .
7.1.3 Toxicity Assessment
A toxicity assessment was conducted for the COPCs identified at au :3 to quantify the
relationship between the magnitude of exposure and the likelihood or severity of adverse
effects (i.e., dose-response assessment). The toxicity assessment also weighed the available
evidence re~g the potential for chemicals to have adverse effects on exposed individuals
(Le., hazard identification). . .
Toxicity values are used to express the dose-response relationship, and are developed
. separately for carcinogenic (cancer) effects and noncarcinogenic (noncancer) health effects.
Toxicity values are derived from either epidemiological or animal studies, to which
. uncertainty factors are applied. These factors account .for variability among individuals, as
well as for the use of animal data to prectict effects on humans. The primary sources for
toxicity values are EPA's Integtated Risk Information System (IRIS) database and Health
Effects Assessment Summary Tables (BEAST). Both IRIS and HEAST were used to identify
the .tox;icity values used in the au 3 risk assessment. . . .
. .
Toxicity values for carcinogenic effects are referTed to as cancer slope factors (SFs). SFs
have been developed by EP A for estimating excess lifetime cancer risks associated with
exposure to potential carcinogens (cancer-causing chemicals). SFs are expressed in units of
(mg/kg-dayrl and are multiplied by the estimated daily intake rate of a potential carcinogen.
to provide an upper-bound estimate of the excess lifetime cancer risk aSsociated with
exposure at that intake level. The upper bound reflects the conservative estimate of risks
calculated from the SF. This approach makes underestimation of the actual cancer risk
highly unlikely. .
Toxicity values for noncancer effects are termed reference doses (RIDs). RfDs are expressed
in units of k~mg-day and are estimates of acceptable lifetime daily exposure levels for
. humans, including sen~itive individuals. Estimatect intakes of chemicals of potential concern
(e.g., the amount of a chemical that might be ingested from contaminated drinking water) are
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TOJlicity values are only available for the oral and inhalation pathways. EPA has not
published toxicity values for dennal contact exposures, and recommends using the oral
toxicity values to evaluate the dennal pathway. In calculating chemical intakes for dermal
expos~res, the oral toxicity values are adjusted by an absOIption factor, which corrects for
the percentage of the' chemical that is absorbed through the skin (compared with direct oral
ingestion). . .
~use of its unique toxicity characteristics, EP A does not currently provide a toxicity value
for lead.' As an alternative to the traditional risk assessment approach, EP A has published
recommended acceptable levels for lead. At the time the baseline risk assessment was
perfonned, these levels were: 500 to 1,000 mg/kg in soil, and 15 p,g/L in drinking water..
Concerltrations at the site were compared with these levels to detennine lead risks at au 3.
Total petroleum hydrocarbons .(TPH) were detected in a number of the samples from au 3.
EPA has not published a toxicity value for TPH in IRIS or HEAST. Petroleum is a complex
mixture of hydrocarbons, many of which can contribute to a detectable TPH concentration.
TPH results are nonnally assumed to be related to contamination from petroleum-related
fuels (e.g., jet fuel, gasoline, kerosene, or diesel). EPA has developed provisional RIDs for
several fuels, including jet fuel (JP,.5). The RID for JP-5 was selected for use in estimating
risks from eXpOsure to TPH at au 3. This RID was selected because JP-5 is documented to.
have been the jet fuel most heavily used on site. .
7.1.4 Risk Characterization
f\ ri'sk characterization was Perfonned to. estimate the likelihood' of adv~rse health effects.
occurring in pOtentially exposed. populations. The risk characterization combines the
infonnation developed in the exposure assessment and toxicity assessment to calculate risks
for cancer and noncancer health effects: .Because of fundamental differences in the .
mechanism~ through which carcinogens and noncarcinogens act, risks were characterized
separately for cancer and noncancer effects. .
. Noncancer Effects
The 'potential for adverSe noncancer effects of a single contaminant in a single medium is
expressed as a hazard quotient (HQ), which is calculated by dividing the average daily
chemical intake derived from t.he contaminant concentration in the particular medium by the
RID for the contaminant. The RID is a dose below which no adverse health effects are
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By adding the HQs for all contaminants within a medium and across all media to which a
given population may reasonably be exposed, a hazard index (HI) can be calculated. TQe HI
represents the combined effects of all tQe potential exposures that may occur for the exposure
. scenario being evaluated. To avoid overestimation of risk, an' m should be calculated by
summing chemicals with a common toxicological endpoint (e.g., the. liver). If the m is less
than 1.0, it indicates that noncancer health effeCts are unlikely. If the III for. a common.
endpoint is greater th~ 1.0, it indicates that adverse health effects. are possible. An In of
less thart 1.0 is EPA's acceptable risk level for CERCLA sites.
. Can~er Risks
. .
The potential health .risks associated with carcinogens is estimated by calculating the
increased probability of ail individual developing cancer during. his or her lifetime as. a result
of exposure to a carcinogenic compound. Excess lifetime cancer risks are calculated by
multiplying the cancer slope factor by the d,aily chemical intake averaged over a lifetnne of
.70 years. .
These cancer risk estimates are probabilities that are expressed as a fraction less than 1.0.
For example, an excess lifetime Cancer risk of 0.000001 (or 10-6) indicates that, as a
plausible upper bound, an individual has a one-in-one-million chance of developing cancer as
a result of site-related exposure to.a carcinogen over a 70-year lifetime under the specific
exposure conditions at the site. An excess lifetime cancer risk of 0.0001 (or 10-4) represents
a chance of one-in-ten-thousand. EPA recommends, in the National Contingen:l Plan .
(NCP), an acceptable target risk range for cancer of 0.000001 to 0.0001' (9r 10 to 10-4) for
CERCLA sites. .' . .. . .
. Results
Table 7-2 summarizes the risk characterization results for each exposure scenario evaluated.
for au 3. Except for future residents, the human health risks were all below EPA's
acceptable target levels (HI less than I, excess . lifetime cancer risk less than 10-4).
Risk. levels were acceptable for both cancer and noncancer effects for the following
populations: current on-site workers, recreational visitors to Clover Valley Lagoon. and
recreational visitors to Dugualla Bay. Estimated risks were also below EPA's acceptable
level for nonC31lcer effects for future (hypothetical) residents that may live near the runway
ditches. Because the estimated risks for these scenarios were belpw EPA's target levels, a
discussion of results for these exposures has not been included. .
F6r hypothetical residents that might live next to the A.rea 16 runway ditches in the future.
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Table 7-2
Summary of Potential Human Health Risks at OU 3
. --. ...........-. ... u.. IR"~~_~~
U":':'!:~IJ9"-:::::::::"_::'
.....:.::...~ij!M.!:":
Area I 6 - Current- Worker Exposure: " ."
RM E HI < I NR NR NR NP NP
CR = I x I 0-5 NR PAHs, As NR NP NP
Average Exposure HI < I NR NR NR NP NP
CR = 7 x 10-6- NR PAHs, As NR NP NP"
Area 16 - Future Resident Exposure:
R M E HI < I b NR NR NR NR NP
CR = I x I 0-4 As, Be As, PAHs NR NR NP
Average Exposure HI < I NR NR NR NR NP
CR ;::: 5 x I 0-6 As NR NR NR NP
Clover Valley Lagoon - Re(reational Visitor Exposure:
R M E . HI < I NP NR NR NP NS
CR ;::: I x 10-5 NP As, Be NR NP NS
~ verage Exposur~ HI < I NP NR NR NP NS
CR = 3 x I 0-7 NP NR NR NP NS
Dugualla Bay - Re(reational Vi9itor Exposure:
RME HI < I NP NR NP NP NR
CR = I x I 0-5 NP As N P NP As
Average Exposure HI < I NP NR NP N P NR
CR = 3 x 10-7 NP NR N P NP NR
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Table 7-2 (Continued)
Summary of Potential Human Health Ris~ at OU 3
FOOTNOTES: .
. Each of. the chemicals listed for a particular medium poses a cancer risk greater ihan 10-<1 or has a noncancer hazard quotient of greater ,han 0.1 due to
exposure pathways for that medium.. Chemicals posing.cancer risk of less than Icr or having a hazard quotient of less than 0.1 for a particular medium are
not listed. No chemicals are listed for any medium for those exposure scenarios having a cumulative cancer risk less than 10-6 or a noncancer hazard index
less than I. .
b Based on target organ. .
CHEMICAL ABBREVIATIONS:
As
Be
Mn =
PAHs =
PCBs =
=
Arsenic
Beryllium
Manganese
Polycyclic aromatic hydrocarbons
Polychlorinate
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(Le., 10-4). The majority of the cumulative cancer risk to futu~ residents is due to arsenic, ,
in soil and sediments, with more than 50 percent of the total risk attributable to arsenic via
~oil exposure pathways. The RME concentration of arsenic in soil for the future residents
scenario is 15.5 mg/kg; this is about 2 times higher than the background value established in
the RI (7.5 mg/kg), but is not unusual compared to normal arsenic concentrations found in
'the region. For example, the RME concentration is less than the MTCA Method A cleanup
level for arsenic in soil which has been established. at 20 mg/kg to account for typical
background values in Washington. Becall;se the RME soil arsenic concentration does not
differ greatly from the RI background value and is not unusually elevated compared 'with
typical regional values, it represents a low i~cremental risk above background conditions.
The remaining overall risk to future residents posed by chemicals other than arsenic in soil is
below EPA's acceptable risk level (the majority of the non-arsenic 'risk is due to PAHs in
ditch sediments).
7.1.5 Uncertainty
. ,
, ,
The' accuracy of the risk assessment depends on the qilality and representativeness' of the data
and assumptions that are used. The main sources of uncertainty associated with the risk
assessment are described in the subsections below; It is important to keep in mind that the
baseltne risk assessment is primarily a decision-making tool for use in assessing the need for,
remedial action. The results of a baseline risk assessment are presented in terms of the
potential for adverse effects based on a number of v~ry conservative assumptions. The
tendency to be conservative is an effon to err on the side of protection of human health.,
. Toxicity Assessment
The cancer slope factor '(CSF) for benzo(a)pyrene was ,used as a surrogate for all PAH
compounds that are classified as probable human carcinogens. Because benzo(a)pyrene may
, be the most potent PAH, this practice may overestimate risks. However:' until more toxicity
data are available on these compounds, it is not possible to conduct a more chemical-specific
evaluation. EPA has developed toxic equivalency factors for PARs, but at the time the risk
assessment was performed, their use had not yet.been adopted. Therefore. this approach was
not used in this risk assessment: '
A variety of chemicals were detected during the'R! for which toxicity values are not '
available. For example, toxicity data (RIDs) are not available for lead or TPH. so they were
excluded from the hazard index calculations. This may result in an underestimate of the
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Arsenic is a COPC in many of the media on site. The toxicological database haS certain
peculiarities that render the toxicity factors for arsenic more uncertain than for many other
chemicals. Uncenainties discussed in IRIS concerning the oral CSF for arsenic imply that
risks for arsenic may be overestimated by as much as an order of magnitude.
Risks associated with dermal contact with soil and sediment were not evaluated for VQCs
. . because competition between volatilli:ation and absorption is expected. to m.ake dermal .
absorption minimal. nere is moderate to high uncertainty regarding the methodology and
absorption rates used for the de'rmal pathway, especially for exposures to water. Dermal
absorption values used for soil/sediment are not chemical-specific, but are based on chemical
class. Funher, the method of estimating dermal absorption from soil and sediment does not
. consider the time of contact. Hence, risk estimates from dermal absorption are' highly'
uncertain.
.. Exposure Assessment.
Many of the exposure assumptions used in the risk assessment are default values in EP A
Region 10 guidance (U. S. . EP A 1991). The RME parameters used to evaluate exposures are .
intentionally. conservative to ensure that site. risks are not underestimated. In recognition of
this. the EP A Region 10. guidance specifies that average exposures are also to be quantified.
Exposures differed significantly between the average an(i RME scenario.. Most exposure
parameters used in the RME scenario were overestimates, whereas parameters for the.
average scenario are more representative of typical exposures.
. .
A conservative approach was used to select potential current and future receptors and
exposure pathways to be used in calculating risks. Current worker, recreational, and futUre
residential receptors were evaluated. However, none of these exposures is very likely for the
ponions of au 3 near the tlightlines. Very little, if any, on-site worker exposure currently
occurs, and recreational/residential exposures may never occur unless the base is closed and
the area is developed for residential use.
Exposure point concentrations of chemicals at the site were assumed to remain constant for
the entire e~posure duration.. N~ degradation or other natural losses of chemicals (e.g.,
migration, dilution). were assumed to occur. As~uming a static chemical concentration for
the entire exposure duration introduces a conservative bias for chemicals that undergo
environmental degradation, migration, or immobilization.
.. Risk Characterization
Because the RME scenario is designed to represent the upper bound of probable exposure
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more realistic, but are still expected to represent conservative risk estimates for a typical
,receptor. Differences between average and RME risks were sometimes quite significant.
For example, the RME risk from ingestion of shellfish from DuguaIla Bay was
approximately 40 times the average risk. '
Cancer and noncancer risks are summed in the risk characterization process to estimate
potential risks associated with the simultaneous exposure to multiple chemicals. In the case
'of carcinogens, this gives probable or possible human carcinogens the same weight as known
human carcinogens. It also equany weights slope factors derived from animal data with
those derived' from human data. Uncertainties in the combined risks are also compounded
because RIDs and cancer slope factors do not have equal accuracy or levels of confidence
and are not based 9n the same severity of effect. These factors may result in an
overestimation or underestimation of risk. '
The assumption that risks from exposure to multiple chemicals are additive does not address
potential synergistic "(greater than additive) or antagonistic (less than additive) interactions.
Slopes of chemical-specific dose-response curves' may differ substantially (i.e., some
chemiCals may be'm.ore potent than others); hence, the respective HQs may not be directly
comparable among different chemicals. RIDs for different chemicals have varying degrees
of confidence associated with them because of variations in'the amount and quality of toxicity,
information and the uncertainty and modifying factors used in developing them. For
, example, all HQ greater than I for a chemical with an RID incorporating high uncertainty
, and modifica~on factors apddesignated as "low confidence" may be of less concern than the
same HQ for a chemical with a better-defmed RID.
Because CSFs typically correspond to the upper 95' percent confideneelimit on the mean
- probability of carcinogenic response (Le., upPer bound estimates), CSFs are inherently
" overly conservative. In addition, the assumption that any exposure to a carcinogen produces
some degree of risk is unproven; hence, it is possible that low levels of some carcinogens
may not ac~ally produce any risk at "all. '
Several pathways were not included in the risk charactenzatlon and are discussed below.
These include risks from dennal contact with groundwater while showering, risks from
exposure,to lead, and risks from TPH. ~clusion of these risks from the risk totals may
cause overall risk to be underestimated. - ,
,Dennal exposure to COPCs in groundwater while showering was omined from the total risk
estimates because, of the high degree of uncertainty associated with the exposure model.
Risks were estimated separately for this pathway for futUre residents at Areas 16. All hazard'
indices were below the EPA target level. No cancer risks from this pathway exist because '
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To semiquantitatively evaluate exposure to TPHs; a provisional reference dose for JP-5 was
used to quantitate risks from exposure to TPH. This RID is highly uncertain because it was
necessary to use inhaJation studies and route-to-route extrapolation to calculate provisional .
RIDs for oral exposure; In addition, the inhalation studies used were subchronic, rather than .
chronic, in duration, and no studies of developmental or reproductive toxicity were available.
The uncenainties associated with the use of this provisional RID are unknown.
Hazard indices were calculated separately for exposure to TPH, using a provisional RID for
JP-5. No hazar4 indices exceeded 1. These risks are highly uncertain because of the low
detection frequency of TPH, the use of a provisional. RID for JP-5, and the unknown type of
TPH on site.
Exposures to lead were characterized' separately by comparing on-site concentrations to
EPA's recommended screening levels for lead. The maximum detected concentration in
Area 16 sediments exceeded the lead screening level of 500 mg/kg. However, the RME
'. concentration .(183.mg/kg) was well below 500 mg/kg. . Furthennore, current and future
exposures are expected to be mininiaJ. Hence, evaluation with EPA's LEADS UBK model
was deemed unwarranted.
In summary, the probability that risks are underestimated is low and the likelihood that risks
are overestimated is high. Estimated future risks are highly uncenain for the following
reasons: l) future land use assumptions are hypothetical (Le., exposure mar never occur),
and 2) the magnitude of future concentrations is unknown. .
7.2 ECOLOGICAL RISK ASSESSMENT
This section summarizes the methods and major conclusions of the ecological risk assessment
perfonned for OU 3. Because the runway ditches are extensive and drain all of Ault Field, .
this risk assessment addresses the ecological aspects of the site from a base-wide perspective.
A screening-level ecological risk assessment was conducted to evaluate potential toxicological
threats to sensitive ecological receptors of chemi~s released into the environment at au 3.
TIUs ev31uation was performed for both terrestrial and aquatic receptors. The overall .
methodology utilized four major approache~ to evaluate potential risks: exposure modeling,
comparison with benchmark values, bioassessments, and comparison with site-specific
biological studies.
. Exposure models use results of chemical analysis. chemical biotransfer factors. and exposure
'factors to provide conservative dose estimates for receptors. Estimated doses are compared
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values (regulatory criteria and guidelines) are available for some chemicals and media for
assessing potential risks to ecological receptors. For example, the federal ambient water
quality criteria (wQC) can be used to evaluate potential risks to aquatic biota associated with
chemicals released in surface water. Bioassessments provide a direct measure of biological
disturbance that can be used to valida'te the results of the exposure modeling and comparisons
with benchmark values. Bioassessments do not identify specific chemicals causing adverse
effects. but they add biological realism to the'risk assessment. Two bioassessment
techniques were used to assess potential ecological risks, in the runway ditch and lagoon
,sediments: toxicity'tests and in-situ invenebrate population studies. '
The Institute of Wildlife and Environmental Toxicology (TIWET 1993) investigated the use
Of terrestrial wildlife populations as biomonitors at selected hazardous ,waste sites at NAS
Whidbey Island (including Area 16). The results of this site-specific biomonitoring ,study
were integrated to supplement and validate the screening-level ecological risk assessm~nt for
the terrestrial habitat.
7.2.1 Chemical Sc~ning
The chemical results obtained for the RI samples at au 3 were evaluated by a number of
initial screening steps to identify chemicals of potential concern (COPCs). These COPCs
were carried through the remainder of the risk assessment to quantify risks at au 3 and
determine the chemicals that contribute most significantly to overall site risks. The most'
significant risk-contributing chemicals are discussed as chemicals of concern (COCs) in
Section 6.2.
The chemical screening steps used to establish COPCs were generally the same as those for
the human health risk assessment described in Section 7.1.1, except for the following
differences:
The initial screening included elimination of chemicals that were detected at a
frequency of less than 5 perceiu of the samples, except in cases where hot
spots were identified. Frequency of detection was not used as a screening step
. in the human health risk assessment.
.
, .
, .
Several'different methods were used for background screening, depending on
the number of sample results available for a given comparison; details are
given in Section 6.3.2 of the RI Repon.
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7.2.2 Exposure Assessment
A diversity of aquatic and terrestrial habitats exist within au 3. Four distinct environments
exist at Area 16 and adjacent downstream areas: terrestrial habitat (predominantly grass-
brushland), runway ditches aquatic habitat (freshwater streaIi1., ripariari habitat), Clover
Valley Lagoon aquatic habitat (wetland, riparian habitat), and Dugualla'Bay marine habitat
(tide flats and subtidal areas). In addition, the runway ditches drain a large ponion of Ault
Field, and thereby collect runoff and any chemicals that may be transponed from these other
areas. These diverse habitats provide food and cover for a variety of terrestrial and aquatic
species. .
Wildlife populations frequenting the site include small mammals (deer mice, Townsend's
. vole, masked shrew), larger mammals (muskrat, raccoon, coyote, long-tailed weasel),
avifauna (nonhem harrier, red-tailed hawk, California quail, great blue heron, and
waterfowl), reptiles (ganer snakes), fish, and a .variety of invertebrates in Dugua1la Bay.
The ecological risk aS~ssment was conducted to detennine whether historical contamination
. at au 3 constitutes a potential threat to wildlife. Because of the extensive area of the ,
runway ditches,. the large size of Area 16, and the diversity of habitat types, the ecological
risk assessment is intended to represent most of Ault Field. '
Species inhabiting the terrestrial habitat are primarily exposed to risks by: initial root uptake
from soils by endemic grasses; ingestion by ammals of soil, surface water. and vegetation;
ingestion by carnivores of small mammals or soil invenebrates~ In the' aquatic habitat,
sp~ies are exposed by ingestion of sediment. surface water, vegetation, fish, or she,llfish.
7.2.3 Toxicity Assessment
The 'screening-level as$CSsment of potential ecological risk compared concentrations. of
COPCs in sediment and surface water to respective q~ty criteria values. The toxicity of
COPCs to specific ecological receptors and ecosystems was evaluated. Relevant
toxicological infonnation from the literature was used to provide a qualitative description of
the .potential toxicity of the COPCs. For terrestrial and aquatic habitats,quantitative TRVs
, were selected or derived for evaluating the potential for adverse effects that may be
associated with a chronic. long-teon exposure;
TRVs for avian and mammalian receptors were expressed as a dose and were obtained from
a review of the peninent literature. Freshwater TRVs for aquatic receptors were derived
from either federal ambient WQC or from the aquatic toxicity literature. Freshwater
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denved from ambient WQC using equilibrium panitioning for non-ionic organic cherrticals.
The sediment TRVs are also referred to as sediment quality values (SQVs).
Acute toxicity tests (bioassays) using several species were also conducted in the lab on
runway ditch and lagoon sediments to provide biological validation of overall adverse effects
predicted from other methods. In addition, population studies were perfonn~ to
characterize the aquatic communities inhabiting the runway ditches and lagoon. This .
identified populations and habitats of ecological concern for. evaluating potential ecological'
risks associated with chemical releases. It also acted as a conflI11latoryin-situ biological
evaluation of impacts on aquatic organisms.
7.2.4 Risk Characterization
. I .
Foyr approaches were used to evaluate potential risks for the different environmental media,
as shown in Table 7-3. Comparison with benchmark values utilized a quotient method to
assess the relative magnitude of potential risk to aquatic populations. For each COPC, a'
. hazard quotient (HQ) was detennined; individual HQs greater than I indicate a potential
stress to aquatic organisms. In addition, estimated chemical doses were compared to TRVs
to predict potential risks to terrestrial.organisms; an HQ greater than 1 indicate potential
toxic effects on the target population. . .
. Table 7-4 ~ummarizes the exposure pathways and receptors that were modeled and evaluated
for the risk assessment. Groundwater was not considered beca~se it is not a significant
ecological exposure pathway. The modeling estimated reasonable maximum exposures'
(RME) to several receptors having different foraging patterns.' . . .
. Runway Ditch Terrestrial.Habitat -- Soil
Potential ecological risks from COPCs in soil, were evaluated by exposure modeling applied
to the vole (herbivorous small mammal), shrew (insectivorous small mammal),. weasel
(carnivorous small mammal), quail (herbivorous bird), and harrier (carnivorous bird).
Modeling results predict that chemicals in the soil pose negligible risks (0 the vole, quail,
and harrier, suggesting that risks to small herbivorous mammals, herbivorous birds. and
raptors feeding along tne ditches is minimal. Evaluation of uncenainty in soil ingestion rates
. for the weasel suggests that adverse risk to this species is unlikely. Potential risks to
terrestrial receptors inhabiting the banks of the runway ditches are limited to exposure of the
shrew to 2,3,7,8-TCDD (dioxm) and selenium (Table 7-5). However, considerable
uncenainty is associated with the potential risk from TCDD because data were limited to a
single soil. sample; the hazard quotient for TCDD was only. 3 times higher than the
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Table 7-3
Overall Meth~dology for Ecological Risk Assessment
1~_II.I..I.i
Dugua1la Bay
Surface Soil .
(0 to 60 cm depth)
Sediment . .
(0 to 22 cm depth)
Surface Water . .
Sediment . .
(0 to 22 em depth)
Surface Water . .
Sediment . .
(0 to 22 cm depth)
Shellfish Tissue .
.
Runway Ditches
.
Clover Valley
Lagoon
.
a Exposure modeling information is provided in Table 7-4.
b Comparison with benchmark values: .
- For sediment. detected concentrations were compared with sediment quality values (SQVs)
- For surface water. detected concentrations were compared with water quality criteria (WQC)
.: Bioassessments: .
-. ~or run~ay ditch sediment. toxicity tests and a benthic invertebrate surVey. were ut.ilized
.. -. . For Clove~ Valley Lagoon sediment. toxicity tests were utilized. . .
" The Institute ~f Wildlife and EnvironmentaiToxicology (TIWET 1993) evaluated sma1~ mamma1 populations near
the runway ditches during a biomonitoring study at N AS Whidbey Island.
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Table 7-4
Ecological Exposure Models Used to Evaluate Potential
. Risks from Chemicals at OU 3 .
!~:j~!!!!!
Eanhwonn~ . .. .
Townsend~. vole . ..
California quail . ..
Ma.ked shrew .
Long-tailed weasel .
Nonhern harrier
.
.
.
.
.
Muskrat
Raccoon
.
.
NOTE:
Small .mmmal'ingeRion applies to ingeRion of Townaerid's vole by masked sh~ and nonhem' hamer.
s
Earthwonn e~olure was used only for mOdeling soil invertebrate ingestion by the masked shrew.
Table 7-5
Summary of Ecological Risks in Soil
I «'.':.,.""",:.'.' ..,:........~....,..,..:.}.""";"",, "';';..'.'.'
"'.:::.:.:<.;:.:::.:::.:::.."
Selenium
1!2,3.7.S-TCDD (TEC)
."',',',
:.','.:.:...
F!:tl
I
I
'~'~::::i
1.3
'H. HIH
.. ..".... .....
o """'" ,....
.., ...,... .....
"H'''''.. "',.
"""."" "....
\:\:':..
..!/~~;:==:.=: ..
230
3 I
:1
. ..
0.00000014 (1.4 x 10'7)
NOTE:
Hazard quotient for maaked shrew based upon results of exposure modeling.
RME
TEC
= . reaspnsble maximum exposure . . .
- Toxicity Equivalency Copcentration (i~dividual dioxins/furans concentrations were con~ened to equivalent 2.3.7,S-TCDD
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may have been significantly overestimated because exposure was primarily through'
. consumption of eanhwonns, and the bioconcentration factor (BCF) used for eanhwonns was
the most conservative value found iri the literature and possibly not representative of site-
specific conditions (a BCF of 52.6 was used in the assessment; other published values range
from 2.1 to 9.6). The RME concentration for selenium was marginally elevated compared
with the RI background value (1.29 mg/kg vs ~ackground of 0.43mg/kg). . .
Results of the TIWET biomonitoring study' showed that voles at Area 16 have similar
survival rates to those at the reference site, although some mortalities were caused by contact
with petroleum hydrocarbons in the ditches. Abnonnalities in liver weights (from unknown
causes). were identified, but concentrations of common metals and organochlorine compounds
were within background levels. In summary, .TIWET results suppon the conclusion of
. 'minimal impact from COPCs to small mammal and raptor populations inhabiting the central
core area.
... Runway Ditch Aquatic Habitat ~ Surface Water
Potential ecological risks from COPCs in ditch surface water were evaluated by comparing
COPC concentrations with WQC and by exposure modeling applied to the heron (a fish-
eating bird)". Both methods suggested that potential adverse impacts are unlikely, although
WQCs and TRVs were unavailab~e for several COPCs..
. Runway Ditch Aquatic Habitat - Sediment
. .
. Potential ecological risks from sediment-borne COPCs in the runway ditches were evaluated
. by comparing chemical concentrations with freshwater secfunent qualitY values (SQVs) and
by exposure modeling applied to the muskrat (aquatic herbivorous mammal). RME sediment
concentrations of 22 COPCs exceeded their SQVs (Table 7-6), suggesting .probable adverse
impacts to benthic organisms. SQVs were unavailable for about one-third of the total
COPCs, so risks are underestimated. Exposure modeling showed that three COPCs had
RME HQs exceediDg I. Considering the uncenainty of secfunent ingestion and the.
conservativeness of the model, only lead is predicted to present potential adverse risk to the
muskrat. .' .
.. The high potential for adverse impacts from sediment-borne chemicals was confirmed by
biological tests. Sediment toxicity tests showed significant epibenthic amphipod mortality in
two central core stations. The bioassessment showed widespread biological impairment of
benthic macroinvertebrate communities throughout the runway ditch system, which was
primarily associated with orgaitic enrichment. However, impairment was greatest in central
core stations where sediment-borne chemicals were detected at uniformly high
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Table 7-6
Summary of Ecological Risks in Runway Ditch Sediments
_rt:::);:1t1t$:~~}i::::ttr....
I: ...'.'."..._:):::~i#:;i#:::::r:~:p.::):ri ......
2-Metbylnaphlhalene 0.91
4.4'-DDD 0.057.
4.4'-DDT 0.012
Acenaphthene 0.74
Anthracene 1.6
Aroclor-1254 0.15
Aroclor-1260 0.14
Arsenic 63
Benzora)anthracene 2.0
Benzo(b )f1uoranthene 1 .3
Benzo(g,h.i)perylene 0.93
Benzork)f1uoranthene 2.5
Dibenz(a.h)anlhracene 0.71
DimethylphthaJate 1 .7
Endosulfan I 0.0036
Fensulfothion 1 .3
Fluorene 1.3
Lead 180
Metbyl azinphos 1.0
Phenanthrene 3 .0
Pyrene 5.3
Zinc 460
:J::tt...;:ft}:::":~:a:~:1cJr(:;:'..)ii:.:::::::.:.::::..
::~~:rI:i:::::Wfr:U{::p~JII~:fflJi:::
44
39
64
1.2 1.4
0.000012 2.8
0.0027 1.7
O.02i 1.1
0.0042 1.7
0.0022 2.4
0.00032 29
3.9 0.74
0.0048 1.3
0.0030 1.4 c
0.0021 3.1 c
0.00057 2.1 "
0.67 2.7
'0,0016 4.1 c
0.00016 8,3 c
0.40 390 c
0.0035 2.0
14 1.7
0.0076 8.4 c
0.23 2.1
0.0016 2.4
- 1.7
.
41
0.10
11
14
a HQs for muskrat are ~ upon results of exposure modeling.
b HQs for benlhic invertebrates are based upon comparison co freshwater sediment quality values (SQVs) (see Section 7.2.3).
c These hazard quotients (HQs) are based onSQVs that are normalized for carbon (i.e., carbon-normalized SQVs expressed
as mglkg organic carbon). The other HQs are based on non-nonnali%ed SQVs. .
mg/kg C = milligram per kilogram.cotaJ organic carbon (carbon-normalized)
RME = reasonable maximum exposure .
NOTE: AJthough manganese. nickel. and vanadium had HQ > 1 for muskrat and/or benthic invenebrates. the incrementa!
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'.
Clover VaUey Lagoon Aquatic, Habitat -Surface Water
No COPCs were identified in surface water, indicating that potential adve~e impacts, are
unlikely. ' ,
. Clover VaUey Lagoon Aquatic Habitat - Sediment
Potential ecological risks from sediment-borne COPCs in the lagoon, were evaluated by
comparing analytical results with SQVs, by exposure modeling applied to the muskrat
(aquatic herbivorous mammal), ana by sediment toxicity testing. '
'Based upon comparison with SQVs, potential aquatic risks to benthic invertebrates were
predicted for seven chemicals having an HQ greater than 1; the'maximum HQ was 6 for
, acetone (Table 7-7). As explained in Section 6.2.5, the HQ for: acetone is likely an anifact,
,of the laboratory. Considering the poorly oxygenat~ habitat in the deep portion .of the.
lagoon (no ecologically significant receptors over a large area), the high acid volatile sulfide
concentrations (which ciu1 reduce bioavailability of certain divalent metals including cadmium
and zinc), and 'the lower HQs in the shaUow ponion of the lagoon, the potential for adverse
impacts on the aquatic ecosystem in the lagoon is low. .
Exposure modeling using the muskrat showed four chemicals with an HQ greater than I; [he
maximum HQ was 5 for dimethoate mainly due to ingestion of vegetation. The other three
chemicals were metals that had HQs close to 1 and represent low incremental risk abo.ve
, background concentrations. Dimethoate was only detected in the deep, poorly oxygenated
portion of the lagoon, which is not where rooted aquatic plants grow.
Toxicity tests were conducted on sediments from Clover Valley Lagoon on two occasions:
December 1992 and July 1993. For each event, two locations were sampled for amphipod
bioassay tests. The two July 1993 samples were also assayed using a larval bivalve (mussel)
as a test species. ' '
All of the bioassay results showed virtually no toxicity and consequently negligible risk.
except for oile of the mussel 'tests, which indicated some adverse effectS (i.e., lower nonnaJ
survivorship than the refeJ'ence station). Because' only one of the six tests showed impacu.
the overall risk indicated by the bioassays is low.
To funher interpret these results, the framework of the state Sedim~nt Management
Standards (SMS) was used. SMS describes two levels of toxicity: sediment quality
standards (SQS), which establish goals that are protective of aquatic organisms in sediments.
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Table 7-7
Summary of Ecological Risks in Clover VaUey Lagoon Sediments
... ..
.. .""J'~~.;_ji.iO~#}:/ ..... .. .
:\H:::::\::)t'H':'H{W;.~~~*:(:::< ...:.,.,:...::
'..:$ido;;f'~~.:¥i~':i.:j~:!~~"of:~,
2.3 6.1
1.1 0.8
2.4 4.1
........... ..... . .
... ..... ........ .. ,...
. . . . . . . . . . . . . . . . .. . . . . . .. .
.... .".....................
......,".........""......
"""""""'"''''''''''
,',',",',".',',',',','.',",',',','.',',',',',',',','
,",',',',',',',',",',",',",",,','.'.'.",',",
...",............ ..........
m;:;)ijl!iq/:
Ac:etone
Cadmium
0.29 0.37
5.4 1.0
0.0042 0.00099
46 'S.3a
160 0.96
1.4 0.079
0.62 0.0047
79 1.7
340 1.0'
3.6
1.1
1.7
1.3
0.8
2.4
1.9
1.5
1.2
0.7
Dieldrin
Dimethoate .
Nic:kel
Selenium
Thallium
Vanadium
Zinc:
a
Thia hazard quotient (HQ) is based on the carbon-nonnalized sediment quality value (SQv) (i.e.. mg/ltg organic: carbon).
Other hazard quotients are based on non-normalized SQVs. .
realOnable maximum exposure
milligram per kilogram .total organic: carbon
RME
rilg/kg C
Notes:
1.
2.
Hazard quotient for muskrat are based upon results of exposure modeling. . ,
Hazard quotient for benthic: in vertebra tea are based upon companIOn to SQVs. preferentially using the state sediment management
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One of the tests (the mussel) failed to meet the SQS levels. All of the results for both the.
mussel and amphipod tests passed the CSL criteria, meaning that active sediment cleanup.
measures are not needed. .
. Clover Valley Lagoon -- Bioassessment
. 'Water quality measurements and sediment coring showed the Clover Valley Lagoon to be
very poorly oxygenated below the 3-meter water depth. 'This anoxic condition and
. consequent diminished value of habitat quality exten~s over much of the lagoon. bottom~
Aquatic vertebrate sampling with a gillnet resulted in no captUres in June 1992, and no
macro benthic invertebrates were found in any sediment cores during the sediment sampling.
Raking the benthos of the east shore with a clam rake produced no clams. Given the high
degree of stratification and resulting anoxic conditions, it appears that the deeper portions of
th~ lagoon may not be suitable for ~ost aquatic biota due to existing conditions.
.. UuguaUa Bay Marine Habitat - Sediment
Potential ecological risks from sediment-borne COPCs in Duguallil Bay were evaluated by
comparing chemical concentrations with SQVs. No COPCs had HQs greater than I,
suggesting. that potential impacts on invertebrates inhabiting bay sediments are negligible.
.. Dugualla Bay Marine Habitat - Sbellf"lSh
. Potential ecological risks from COPCs in ~hellfish tissue from Dugualla Bay were ~valuated
by exposure modeling applied to.tbe raccoon (omnivorous mamm31) through ingestipn of
clams (conservatively assumed to comprise half of the raccoon's diet). No COPCs had HQs
greater than. 1, suggesting that potential impacts on animals ingesting shellfish are negligible.
7.2.5 Uncertainty
This uncertainty analysis provides a qualitative evaluation of the assumptions and limitations
inherent in the ecological risk assessment. The main' sources of uncertainty associated with
the risk assessment are described in the subsections below. The results of a baseline risk
assessment are presented in terms of the potential for adverse effects based on a number of
very conservative assumptions. The tendency to be conservative is ~ effort to err on the
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. Chemical Screening
The screening methodology employed in the risk assessment used conservative input values
and assumptions to establish risk-based screening values for selecting chemicals of potential
concern. Because the input values and assumptiQns were. conservatively selected, it i~
unlikely that potential ecological risks for any chemical were underestimated, unless an input
value was not available. For example, there Were cases where a toxicity reference value was
not available for a panicular chemical, and therefore. the potential risk due to the chemical
could not be estimated.' It is likely that the cumulative risks estimated for panicular
, ' receptors may'have been underestimated because of this, and it is possible that some
chemicals were screened out that could be partly responsible for adverse effects observed in
, the non-chemical assessments (Le., bioassays and bioassessment surveys). On the other
hand, it is likely that the use of conservative input values and assumptions for the remaining
chemicals led to overestimation of risk for the chemicals that could be included in the risk
calculations.
. , Exposure Assessment
Exposure models were based on receptor ingestion rates of water, forage, soil, and sediment.
'Water and forage ingestion rates were not site-specific. Soil and sediment ingestion rates
were not site-specific and not species-specific. .
Some of the factors' needed to estimate exPosure for all ~eptors 'were not available. In
these cases, no exposure was estin1ated and overall risks were underestimated. Also, the use
of conservative non-site-specific exposure factors probably overestimates exposu~. '
Biotransfer factors were' used iri the, exposure models to estimate chemiC3.l tissue'
concentrations in prey species. These factors were based on a limited number of species and
chemicals, ~d may ~ot be representative of actual site conditions.
The exposure mOdels include an assumption that receptors are continuously exposed to an
environment with a uniform distribution of chemicals. Because many animals will not
inhabit the contaminated area 100 percent of the time, exposure may be overestimated for
rnany receptors. .
Using the RME value instead of the average overestimates risk. RME values typically range
from 1.2 to 1.4 times the average value. Hence, risks may be overestimated by 20 to
40 percent compared with average concentrations.
. .
Many chemicals may exist in a state th~lt is not readily bioavailable or is not the most toxic.
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. concentration" could be unavailable and then would pose little risk to biota. Bioavailability
could have a. moderate effect on overestimating risks as compared with the measured
concentration of those chemicals.
. Toxicity Assessment
Typically, TRVs were not available for the receptor species. Therefore, values for species
of similar taxonomic classification were used, often from laboratory studies using standard
laboratory test organisms. The direction and magnitude of uncertainty is unknown.
Toxicity values were not found for all COPCs. Therefore. potential Iisks were nO,t estimated
for these COPCs and cumulative risks were underestimated.. '
I~ some cases, the toxicity values were extrapolated from one endpoint (e.g., LD5O> to the
no-observed-effects level (NOEL) or lowest~bserved-effects level (LOEL). . This
extrapolation was based on generalized published relationships that may not he pertinent to
the organisms or chemicals iri this. study. . .
Results of the toxicity tests perfonned on sediments can be influenced by at least three
factors that contribute to uncertainty: asseSsment endpoints affected by basic physical and
chemical conditions that are not reflective of chemical contamination, uncertainties in
counting test organisms or assessing their behavior, and variability in bioavailability of
chemicals among samples.
. Risk Characterization
At lea!;t some chemicals, when acting in mixtures, may pose risks that are greater than the
sum of the individual risks. Very little is known of such synergistic effects of toxicants.
When synergistic effects occur, but have not been accounted for, the overall risk may be
underestimated. .
For at least some chemicals, adaptation by organisms may occur. After adap~g to
particular chemicals in their environment. or in some cases in their tissues. organisms may
. carry out life functions that would otherwise 'be impaired at those concentrations. In these
cases, risks based on measured concentrations would be overestimated.
The interpretation of potential ecological risks based upon HQs calculated from exposure
. modeling is ill-defmed. This ecological risk assessment has used an HQ of greater than I as
an indicator of potential impacts to ecological receptors. However, some workers state that
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than I o indicate a probability that ecoiogical impacts would occur. . Many of the COPCs
identified as potential risks in exposure models in this risk assessment had HQs below 10.
The macroinvertebrate bioaSsessment that was conducted oil the runway ditches provided
direct biological evidence of impacts on the benthic macroinvertebrate community. .
However. some uncertainties exist in its application. The macroinvertebrate bioassessment
method was designed for use on relatively healthy stream systems with abundant and diverse
benthic insect comDlunities. The benthic. macroinvertebrate communities inhabiting the
runway ditches had poor diversity and abundance, and were devoid of many msect taxa used
in assessing impairment. In addition, organic enrichment of the entire stream bed caused a
substantial decline in habitat quality, which confounded the delineation of impact potential of
COPes.
As discussed at the beginning ~f Section 7.2, the ecological risk assessment employed several
different approaches to evaluate risks, including comparison of chemical concentrations with
toxicity reference values, bioassays and bioassessments. Using a variety of approaches was
intended to help overcome some of the uncertainties inherent to each individllal approach and
produce a better overall understanding of the eCological risks at- OU 3. . . . .
8.0 REMEDIAL ACTION OBJECTIVES
This section explains the basis for remedial action at OU 3, identifies the media for which
action is needed, and describes the objectives that the remedial action is. intended to achieve.
Based on these remedial action objectives (RAOs),. specific cleanup levels are defined for
specific. chemicals in.the media of concern. Based on the cleanup levels, this section also
identifies specific areas of OU3 that. have ~n selected for remedial action. .
8.1 RUNWAY DITCHES
The following subsections discuss the need for remedial action, establish cleanup levels, and
identify selected remediation areas for the runway ditch complex. The ditch complex'
includes all pans of Area 16 upstream of the Clover Valley Lagoon. Section 8.2 discusses
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8.1.1 Need for Rememal Action
The baseline risk assessment evalUated exposures to current workers and hypothetical future
, residents applicable to the soil, groundwater, surface water, and sedjments of the runway
ditch complex. As discussed in Section 7.1.4, the ~stimated human health risks were below
the CERCLA target levels for all the exposure scenarios except for. cancer risks to future
residents. . , '
For hypothetical residents that may live next to the ditches in the future, the estimated cancer
risks were at the upper end of EPA's acceptable risk range (i.e., RME cancer risk was 1 x
10-4). Because the estimated risk is marginal compared with the acceptable target level,
because the majority of this risk is due to arSenic in soil at concentrations similar to
background levels and below MTCA Method' A cleanup levels, and because RME risks
reflect a number of conservative assumptions, the risk to future residents does not warrant
cleanup actions.
, "
Thus, the baseline risk assessment did not demonstIate a need to take remedial action at the
runway ditches to protect human health. The following subsections discuss the need for
remedial action in regards to the results of the ecological risk assessment and consideration
of ARARs for the soil, groundwater, surface water, and sediments of the runway ditch
complex.
.
Soil
. "".
The baseijne risk assessment identified potential ecological risk" based on the masked shrew
exposure mod~l, for two cbemicals in soil along or near the banks of tbe runway ditches:
selenium and dioxin. State standards for soils (i.e., MTCA cleanup levels) were exceeded in
some of the soil samples for arsenic, beryllium, manganese, and petroleum hydrocarbons.
None of these chemicalS is considered to pose significant risks warranting remedial action
because of the following reasons: '
.
Selenium, arsenic, and petroleum hydrocarbons were infrequently detected
above the ARAR or risk level. The dioxin risk was based on analysis of only
one ,sample.
For selenium, arsenic, beryllium, manganese and petroleum hydrocarbons, the
samples indicative of risk were distributed in widely spaced locations not
indicative of an obvious source.
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.
For dioxin, arsenic. beryllium, manganese, and petroleum hydrocarbons, the
ARAR or. risk level was exceeded by only a marginal amount.
.
For selenium, arsenic, beryllium. and manganese, the detected concentrations
were similar to background concentrations. .
For these reasons, no remedial actions are considered to be necessary for the soil at the
runway ditches. .. .
.
Groundwater
Because there is no exposure route; groundwater does not pose an ecological risk. However,
several chemicals were detected in the groundwater at concentrations above drinking water
standards or state cleanup levels: arsenic, manganese, dinoseb, and 2,4-D. The latter two
chemicals are herbicides. ..
Most of the groundwater results for arsenic were clo~e to or below the MT~A ~ethod A
cleanup level. One of the wells had concentrations about 2 times the cleanup level, but the
concentrations were not unusually elevated compared to typical regional background values,
and were well. below the federal drinking water standard. The manganese results were also
not unusual compared with regional conditio~s. Hence, arsenic and manganese in the
groundwater are not considered to pose a significant excess risk compared with naturally
occurring background levels. .
The detections of herbicides in the groundwater are considered to be laboratory anom~es.
As explained in Section 6.2.2, the dinoseb and 2,4-D detections in the Phase I samples wei:e
. associated with interferences making the ~sults questionable. These detections were not
confmned by resampling in .Phase n. The Phase n analyses had no interference problems
and the detection limits were well below drinking ~ater standards. . .
Because the herbicide exceedances are considered anomalous and the arsenic concentrations
are considered typical of natural background levels, remedial actions are not necessary for
the Area 16 groundwater. .
.
Surface Water
No significant ecological risks were identified in the baseline risk assessment for the surface
water in the runway ditches. However, surface water ARARs (i.e., water quality critena
and MTCA cleanup levels) were exceeded in some of the ditch water samples for four
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, ,
None of these chemicals is considered to pose significant risks warranting remedial action,
because: 1) the chemicals were infrequently detected above' background levels, 2) none of the
results greatly exceeded the background concentrations, 3) only a few samples exceeded the
ARAR concentrations, 3) the few results above ARARs were found in widely spaced
locations riot related to manmade sources, 4), the ARAR or risk level was exceeded by only a
small amoun~, and 5) detected concentrations were often not coi1firmed,by resampling. For
, these reasons, no remedial actions are consideied to be necessary for the surface water in the
'runway ditches. . ,
.
SediliJents
There are no federal or state ARARs for fresh water sediments. However, the baseline risk
assessment identified significant ecological risk a~butable to chemicals detected in the "
runway ditch sediments. The ecological risk was predicted based on the results of exposure
modeling using the muskrat as a receptor, and, the exceedance of sediment quality gui~elines
, for p~tection of.benthic organisms. . The following types of chemicals were identified as
contributing to 'the ecological risk in the sediments:
.
.
.
metals (arsenic and lead)
votatile organic compounds (VOCs) ,
semivolatile organic compounds (SVOCs, including polynuclear aromatic
hydrocarbons [PAHs))
pesticides
herbicides
PCBs
.
'.
.
In addition to these chemicals, high concentrations of petroleum hydrocarbons were detected
at 'several of the semment stations, which are a likely source of the SVOCs, PAHs, and lead
that contribute to the overall ecological risk. The prediction of significant risk from the SQV' ,
and muskrat evaluations was confmned by the results of sediment bioassays and benthic
community assessments for selected stations. .
, ,
The weight 'of evidence frpm the muskrat exposure modeling, the benthic assessments. and
the' sediment bioassays mdicates that remedial actions are necessary in order to reduce the
. ecological risk posed by chemicals detected in the runway ditch sediments.
8.1.2 Remedial Action O~jectives
For- the reasons discussed in Section 8.1.1, remedial actions 'are needed to address
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actions is to reduce ecological risks posed by the contaminated s~iments, as identified in the
baseline risk assessment.
In addition to this remedial action objective, the Navy desires to minimize future constraints
on dredging of the runway ditches that are currently in effect because of the sediment .'
contamination. The ditches must be periodically dredged to maintain free-flowing conditions
because they serve as a major drainage network for Ault Field and the surrounding .land.
Without periodic dredging, flooding may eventually occur. . In the past, the Navy has
dredged'the ditches as needed to prevent flooding and has disposed of the dredged' material
next to the ditch banks. Placement of the dredged material on the ditch banks is a practical
and cost-effective means of disposal, especially for ponions of the ditches where access is
difficult or is limited by flight operations. Because of the potential for contaminants in the
sediments, this disposal practice has been discontinued during the remedial investigation. In
order to resume this . cost-effective practice, the Navy desires to take cleanup actions that will
minimize contaminants in the ditches. that may need to be dredged in the future, so that
dredging can be conducted for maintenance purposes without the restrictions that are
currently in pl.ace. . . .
Once cleanup actions have addressed contaminants in the ditch sediments, it is not likely that
they would become recontaminated in the future. The Navy 'has instituted best management
. practices to reduce runoff from industrial areas into the ditch complex.' It also has an
emergency response plan that greatly reduces the chances of an accidental fuel spill reaching
the ditches. If fuel did reach the ditches. it would be contained and pumped from the ditch
at baffle number I. The past practice of disposing waste into the ditches no longer occurs.
Other Navy programs (recycling and waste minimization) have greatly reduced the amount of
hazardous materials handled at the base. In addition, the 'Navy routinely monitors the ditch'
effluent that leaves the base as pan of its National Pollutant Discharge Elimination System
permit. All these programs and the spill response plan are designed and implemented to
prevent recontamination of the ditch sediments or release of pollutants into the marine.
. environment. For additional assurance, the Navy plans to install storinwater treatment at
various locations, where needed, throughout NAS Whidbey IslaJid: the runway ditches are .
being considered in these plans.
In order to minimize constraints on future dredging, risks that may be pos~ by the dredge
spoils must be' addressed. Ecological concerns for the dredge spoils would be addressed by
remedial actions designed to achieve the principal objective of reducing ecological risk posed
by the contaminated sediments themselves. In addition, there may be human health concerns
related to the dredg~ spoils. Once the sediments are placed on the ditch banks, they will
become soils that may pose human health risks via soil exposure routes. The baseline risk
assessment did not evaluate this exposure scenario. because it is associated .with futu~
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dredging activities, prevention of unacceptable human health risks from this exposure
. scenario has been included as an objective of the remedial actions. .
In summary, the. remedial action objectives for the ditch sediments includ~:
.
R,eduction of current ecological risks posed by chemicals of concern' in the
ditch sediments. .' ..
.
Reduction of future human health risks that may occur if contaminated
sediments are dredged for ditch maintenance purposes and placed on the ditch
banks, where the sediments will become soil and result in human exposures to
chemicals of concern ~ia soil exposure pathways. .
8.1.3 Cleanup Levels .
'. .
. The RAOs defIned in the previous section include reduction of both current ecological risks ..
and potential future human health risks. Chemical-specific cleanup levels that correspond
with these objectives were derived from the following:
.
Concentrations in the sediments. thai are equivalent to a hazard quotient oj 1. 0
based on the muskri:u model used in the baseline risk assessment. Cleanup to
these concentrations would eliminate ecological risk predicted by the model for
the muskrat as an indicator species. The muskrat model was selected for this.
purpose because risks to other indicator species modeled in the baseline risk .
assessment (Le., heron) were found to be acceptable without. remediation.
.
Concentrations in the sediments thai exceed MTCA Method C cleanup levels
for industrial soil. Cleanup to these concentrations would minimize potential
human health risks to workers that could be e~posed to the sediments if they
were dredged in the fu~re for maintenance purposes and placed along the
ditch banks. The soil cleanup levels are appropriate because, after pl3.cement
on the ditch banks, the dredged sediments will become soil. MTCA.Method 8
. 'Cleanup levels; which are based on human health risk for residential exposures..
were not selected for this purpose' because the land use at the ditches is nO(
expected to be converted to residential use in the future. Future residential
development is very unlikely because of the presence of the air fIeld, which
would probably remain as a non-military ailport if t~e base were to close. and
because the wetlands surrounding the ditches would make development
unlikely. . If future land use changes to non-industrial, this situation would be
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.
Concenlrations in the sediments that exceed the MTCA Method A industrial
cleanup level for total petroleum hydrocarbons (I'PH) in soil. Cleanup to
these concentrations woul,d reduce potential human health risks to workers that
could be exposed to the sediments if they were dredged in the future, as
discussed above. The Method A cleanup level was included because there is
no Method C cleanup level for TPH. '
.
Concentrations in the sedimenls that exceed background levels. In cases where
the sediment background level is higher than any of the risk-based or ARAR- '
. based cleanup levels described in the previous bullets, the background value,
will be the basis for remedial action decisions.
The cleanup levels described above were compared with the maximum concentrations of
chemicals detected in the RI ditch sediment samples' in: order to detennine target chemicals
for remedial action. The results of this comparison are shown in Table 8-1, which lists the
maximum detected concentrations, the cleanup levels based on the muskrat model, and the
Cleanup levels based on MTCA. ,Table 8-1 lists all the chemicals for which the maximum
detected concentration exceeded the minimum cleanup level. Detected chemicals that did not
exceed the minimum cleanup level in any of the sediment samples are not included in the,
, table.
The cleanup levels listed in Table 8-1 differ from the preliminary remediation goals used to
develop and evaluate alternatives in the' feasibility study. As this record of decision was
developed. the preliminary remediation goals were reevaluated and revised. Differences
between the preliminary remediation goals and the fmal cleanup levtfls in Table 8-1 are due,
to the use of MTCA cleanup levels, sediment quality values, and TPHconcentrati9ns. Each
. of tbese differences is discussed in the following paragraphs.' ,
MTCA cleanup levels for soil were included as fmal cleanup levels for the sediments to
address a potential future human exposure pathway, as explained above in the second bullet.
MTCA soil values had not been included in the preliminary 'remediation goals because the
baseline risk assessment and feasibility study did not consider this potential pathway.
In addition to the muskrat and heron models" the ecological baseline risk assessment
quantified risks in the ditch sediments by comparing sediment concentrat!ons t9 sediment
quality values (SQVs) such as those developed by the Ontario Ministry of the Environment.
These SQVs were used as preliminary remediation goals in the FS, but have not been
retained as fmal cleanup levels. The SQVs are concentrations at which adverse ecological
effects. ma~ be expected to occur to benthic organisms, and were developed to protect '
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Table 8-1
Cleanup Levels for Runway Ditch Sediments
E..li__-
......
'::';'::':':';';:':':':".:.:.'.:.:-:.:
'.",..'...','.....".'.".'.".'.','."
.. . . .. . ... . .. . . . . . .
....n.., .. ...
",""",
:"':':':':'.' "Siihcililcf:':':':':""
::::;:j::::::m::::'J..::.iij:i...::i
:'::::::::::::-::::':':1::::11::
Arsenic:' 581 3.4 188 16 16
Lead 942 18 140 14 18
2-methy1naphIha1ene. 3.2 0.8 0.8
Benzo(k)fluonnlhene 23 18 450 18
Dibenz(a.h)anthnc:ene 1.9 18 l.l 1.1
Phenandlrene 20 13. 13
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intended to protect prime water resources. they are overly conservative and not appropriate
as cleanup levels for ditches. For this reason, and because the SQVs are not ARARs,
cleanup levels based on the SQVs were not included, in Table 8-1.
The MTCA soil cleanup level for TPH has been included as a rmal cleanup level for
sediments, although it was not listed in the FS Report as a preliminary remediation goal
because this ARAR applies to soils rather than sediments. In addition to the reasons given
above in the third bullet, the cleanup level for TPH has been included, as an' indicator of
ecological' risk. Ecological risks attributable to TPH were not quantified in the ecological
. risk assessment, because of the lack of pertinent toxicity data. Nonetheless, the TPH data
collected in the RI correlated well with ecological risk in the sediments. This is shown in
. Table 8-2, which compares TPH results for sediment. stations where bioassay samples were
analyzed or where benthic community assessments were perfonned. The data in Table 8-2
suggest that adverse ecological effects may occur in the sediments at concentrations on. the
order of 4,000 mg/kg and above. That is, no adverse ecological effects were found for
station 16':11 which had a TPH conceritrationof 4,350 mg/kg, whereas community
impainnent was noted for'sration 16~7 having. 3.860 mg/kg TPH. ,At much higher TPH
concentrations (stations 16-4 arid 16-6), adverse effects were observed in .both the bioassay' .
and community assessment results. These results suggest that TPH can serve as an indicator
of ecological risk in the sediments and that a concentration of abput 4,000 mg/kg may be an
appropriate cleanup level for this purpose. Cleanup to the MTCA Method A cleanup level
for TPH (which is 200 mg/kg) would therefore also address the ecological risk that appears
to be associated with TPH. .' ,
8.1.4 'Selection of Areas for Remediation
The highest concentrations of contaminants contributing to the ecological risk were found in
the sediment stations located closest to the Ault Field runways and taxiways, where major
stonn sewers from the base discharge into the ditches. In the past, wastes were discharged
into these sewers, contaminating the ditches. Lower contaminant concentrations were
detected in the sediments farther from theruriways, and concentrations were found to
generally decrease along the ditches downgradient of the runways towards the Clover Valley
Lagoon and Dugualla Bay.' , ,
. .
In order to identify parts of the ditches that should be remediated to attain the remedial
action objectives, the maximum concentrations detected at each station were compared to the
cleanup levels listed in Table 8.; I. Table 8-3 shows the maximum concentration detected at
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Table 8-2
Comparison of TPH Concentrations in Ditch Sediments
With Bioassay and Benthic COmn1unity Assessment Results
fj~~te'III.fl~'!!.III~I_i'l5tj;!:1
16-6 6. 123.000 YES YES
164 5 45;000 YES YES
16-7 4 3.860 NT YES
16-11 9 4.530 NO NO
16-8 2 139 U NT NO
U = Not detected (the value listed is the detection limit).
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R~\.i~illll Nil 0
nal~ 01'2"''15
Page 6-J
Table 8-3 .
Maximum Deteeted Concentrations ~t Runway Ditch Sediment Stations
.. ..
~$.iijAA ..~..$.Q~iji~iki$~iiiij~ijgii rlf~~ i~fUii t~t }~i} tSijWi.ij:tli!!/Ar:.iiit }$.iffii!i:gg,r
Il~~. .'.n4:?J~~.. .('~t::J.~{. .4re1.:4~:J~~tl~!g.. :::i'!FUr::r'E)J,t: ::t'+.Mt :tnmnm:..:Uf\n;.]E~':r/1~M\ :1M~t
........ (?pg~)
q~..Jltt..
I....'...
. ..... ..
Ars~nic
lead
2-melhyl
naphthal~ne
Benzn(k)
nU(Jranlh~n~
Dih~nz(a,h)
anthracene
Phenanthrene
TPli
16
18
0.8
18
I J
.
13
200
6
13
6
42
87 13 13 14 13 20 5
6 942 831 160 6 17 4
3.2 0.26
23
I
20
45,000 123:000 3,860
30
147
28
77
9 13
17 27
1.3
4.1
1.9
0.7
269
4
15
44
15
31
16
581
379
0.57
170
0.81
4.200
446
4.530
213
117
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Table 8-4 presents the same info~ation as Table 8-3, except the chemical results for each
station are nonnalized by dividing the maximum concentration detected at the station by the
, corresponding cleanup leveL When noimalized in this manner, values greater than I indicate
an exceedance of the cleanup level and thus identify stations where reIIiediation should be
considered. For purposes of clarity, values less than 1 have been omitted from Table 8-4.
,The nonnalized results in Table 8-4 ,are intended to distinguish which 'stations have the,
highest risk from those'with lesser risk, relative to the cleanup levels. For example, an
exceedance value of 20 in Table 8-4 means that the chemical exceeded the cleanup level at .
, that station by a factor of 20, whereas an exceedance value of 2 means that the chemical
concentJ'ation was only 2 times the cleanup l~veL
Based on the exceedances of cleanup levels illustrated in Table 8-4, the following stations
were selected for remedial action: 16-4, 16-6, 16-7, 16-11, and 16-35. These. stations are
identified.as shaded columns in Table 8-4, and their locations are shown in Figure 8-1.
, These stations were selected for remediation based on the following considerations: '
.
Stations exhibiting the highest risk, as indicated by, the exceedance values in
Table 8-4 much greater than I', were selected for remediation. These stations
were selected because they appear to represent 'areas, of more serious '
contamination.
.
Stations exhibiting high TPH concentrations (exceedance values of about 20 or
more in Table 8-4) were selected for remediation. High TPH concentrations
were used as an indicator of significant ecological risk, for the reasons
. . discussed in Section 8.1. 3.
Stations were not selected for remediation based on the following conditions:
.
Stations having only one or two chemicals with relatively small exceedance
values were not selected for remediation.
.
Stations 16-9 and 16;..31 were not selecteq for remediation because of their
proximity to the heron rookery in addition to the relatively low exceedance
values associated with these stations. The ecological exposure assessment
. using the heron as a receptor did not show significant risk to these birds, for
chemicals detected in the sediments. Remedial actions at these stations would
result in unavoidable disturbance of the rookery and destruction of part of its
habitat. In view of the protected status of the great blue heron and the
. relatively low risk to other organisms posed by the sediments at these stations.
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Table 8-4
Exceedances of Cleanup Levels at Runway Ditch Sediment Stations
2
2
4
3
.:
:t:::~~:':'\:
):::,(:::!::
Arsenic 16
Lead 18
2-melhyl 0.8
naphthalene
Benzo(k) 18
fluoranlhene
Dit>enz(a.h) 1.1
anlhracene
Phenanthrene 13
TPH 200
s
2
2
2
2
I
2
Nilles:
1. The shaded column!! indicate those stations selected for n:mediation.
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, Dugualla
"BaY,.~. '/
, ", ' ~,~~('J"
, ,Clover Valley. fl«:, ""':.'\,'.",'.'.~'.' " H
\ "":- - - - - .:...... L ; it', ,:::",«
I I 1 J 'agoon ,,-,~,>,< )f~',\<,;.>;
- - - - - - - ~ - , ~. ~ :~g'::x>""j~~T~~f'~~~~~
~0"d I ~ / '!::,;2L.L_1/ .
~~ I CREEK.
~~~---_' '
...o~
Cj" '
)
)
H
I
\
\
\
..."
.......
I
J
,
,/
//
I '
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i
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NOTE: See Figure 6-3 for stalion locations.
CLEAN
COMPREHENSIVE
lONG-TERM
ENVIRONMENTAl.
ACTION NAVY
Figure 8-1
DilCh Segments Selected lor RemediaUon
CTOlflROI»GI.I.ORW 1'22m
)
LEGEND
~ OUches for Remediation
Major Ditch Channels
<
Flow Direction
----------.
Qulvert or Sewer
---
Base Boundary
:.#:: Wellands
1+1
o
2000
SCALE IN FEET
CTO0074
OPERABLE UNIT 3
NAS WHIDBEY. WA
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NAS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0074
, Final Recoi-d. of Decision'
Revision No.: 0
Date: 03/29/95
Page 68
Sev.eral of the ditch sediment stations not. selected for remediation exhibited moderate
exceedance values for arsenic and lead (e.g., Stations 16-3 and 16-12). Such stations were
not selected for the following reasons: .
.
Except for a few of the sediment. stations, the RI data showed arsenic and lead
to be widespread, non-localized chemicals detected throughout the ditches at
. concentrations not substantially different from background values. Because of
statistical variations in background coricentrations for these chemical's,: many of
the moderate exceedances found in the ditches may not represent a significant
contaminant source that is distinguishable from background levels.
.
The. estimated ecological risk. posed by l~d and arsenic at the nonselected
stations is relatively small and represents an increment above background that
may not be significant.
.
Remediation oinon-Iocalized arsenic and'lead concenttations would be .
impractical because of the large areas of the ditches and large volumes of .
sediments that would be. involved.
.
There is considerable uncenainty in modeling and quantifying human and
ecological risks. To accommodate this, the assumptions and models used to
evaluate chemicals of potential concern in baseline risk assessments are
selected to be overly conservative, and thus tend to overstate actual risks.,
Because of this, some latitude in selecting areas for remediation is prudent in
order to avoid exc;essive cleanup expenses that may not achieve significant' .
. benefits. The' non-chemical bioassessments conducted for the ditch sediments
suppon this idea. For example, the bioassay and bioassessment results showed
no adverse effects or benthic impainnent at station 16-11 (see Table 8-2) in
spite of the moderate exceedances of cleanup levels at this station shown in
Table 8-4 for arsenic, lead, andTPH. This evidence indicates that the lesser
exceedances of cleanup levels for the un shaded 901umns of Table 8-4 do not
likely represent significant risk.
Several of the stations have much higher concentrations of arseriic and lead that are abnormal
compared with typical background values, and are associated with high concentrations of
TPH. These stations have been selected for remediation, so that substantial risks attributable
to arsenic and lead will not be ignored. . .
. The sampling. strategy employed in the remedial investigation was to select .a reasonable but
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CTO 0074 '
Final Record of Decision
Revision No.: 0
Date: 03/29/95
Page 69,
source inputs such as stonn sewer discharge points, that would allow for cost-effective,
. identification of those pans of the ditch network for which remedial action is needed. This
has been accomplished, with the stations selected for remediation as described in the above
paragraphs. As pan of this strategy, further sampling of the ditches in th~ vicinity Qf these
selected stations will need to be conducted during .i'einediai design, in order to establish the
full extent of the areas to be remediated. '
8.2 CLOVER VALLEY LAGOON AND DUGUALLA BAY
In consideration of CERCLA requirements and the evaluation of risks associated with the
Clover Valley Lagoon and Dugualla Bay, no remedial actions are deemed to be. necesSary for
" this portion of au 3 to ensure a
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.'
NAS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
Engineering Field Activity. Northwest
Contract No. N62474-89-D-9295
CTO 0074
Final Record of Decision'
Revision No.: 0
Date: 03/29/95
Page 70 .
The lagoon sediment bioassay test results confmn a low potential for ecological impacts.
. The risks indicated by the bioassay tests were evaluated by comparison with the state
sediment quality stan~ (SQS), which indicate no-effects levels, and the state sediment
cleanup screening levels (CSLs), which are used to detennine when cleanup actions are
necessary. Only one of two test species in one of the six sediment samples failed to meet the
SQS level. None of the tests failed the CSL criteria. Because all but one of the tests
. showed little or no impact, the overall risks measured' by this approach are low. Because all
. of the tests passed the CSL criteria, the results indicate that no active. cleanup measures are
. warranted for the lagoon sediments. . . .
The remedial investigation detennined that the absence of aquatic life in the bOttom portion
of the lagoon is due to the anoxic condition (Le., lack of oxygen) in the deeper pans of the
lagoon rather than chemical contamination. The anoxic condition was caused by construction
of the dike that separates the lagoon from Dugualla Bay. The dike has interrupted the
natural tidal action in the original estuary that fonnerly mixed the water in the estuary and
. provided oxygen to its deeper portions. The chemicals detected in the deep lagoon sediments
are not believed to be the cause of the' absence of aquatic life in the bottom of the lagoon.
. As discussed above, the risk associated with these chemicals is' low and similar to
. background conditions. Furthennore, . the HQ levels observed in the shallow sediments were
similar to those in the deep sediments, whereas there is no life at the bottom but the. upper
. part of the lagoon is a viable ecosystem that supports a large stickleback fish population,.
snails, and migratory birds. This comparison supports the. conclusion that the absence of life
at the bottom. of the lagoqn is due to its anoxic condition rather than contaminants.
Aquatic life will not flourish in the deeper pan of the lagoon unless the anoxic condition is
removed. The anoxic condition could be rectified by renioviIig the dike, but such an action
. would not likely be supported by all citizens because the dike prevents flooding of the.
adjacent farm lands. With further study, it could be detennined if other actions would be
able to remove the anoxic condition. However, removal of the anoxic condition is not
related to chemical contamination from past practices which CERCLA is intended to a~dress,
and such actions are' therefore not within the scope of.this ROD. Even if the anoxic. .
condition were ameliorated, the low level of risk posed by the chemicals detected in the
lagoon sediments would still not warrant remedial actions, for the reasons discuss~ earlier.
9.0' DESCRIPTION OF ALTERNATIVES .
The feasibility study (FS) assessed a range of alternatives for remediation of Area 16 (URS
I 994b). Based on the results of the risk asseSsment and the remedial action objective~
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NAS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
Engineering Field Activity. Northwest
Contract No. N62474-89-D-9295
CTO 0074
Final Record of Decision
Revision No.: 0
Date: 03/29/95
Page 71
contaminated sediments in the runway ditches. No alternatives were developed for. '
remediation of other media because associated risks do no warrant remedial actions for media
besides the ditch sediments. '
. . . .
A total of three alternatives were evaluated for possible, implementation at Area 16:
.
.
.
, Alternative I - No Action ,
Alternative 2 - Ditch Rerouting and Backfilling
Alternative 3 - Sediment Removal and Disposal
, The following sections provide a brief description of each alternative evaluated in the FS,
including the estimated capital cost and operating and maintenance (O&M) c~sts for
implementation. ' ,
" 9.1 ALTERNATIVE 1 - NO ACTION'
The no-action alternative was included in the range of alternatives evaluated in the FS, as
required by the National Contingency Plan.' Alternative 1 includes no specific response
actions to reduce contaminants at the site; control their migration, or prevent exposures. The '
no-action alternative serves,as a baseline from which to judge'the performance and cost of
other action-priented alternatives.
There is a need at the base for periodic dredging to assure that the ditches adequately carry
stprmwater away'f~m the airfield operations area and runways. 'In the past, the Navy has
placed the dredgings from such routine maintenance next to the ditch banks, and wants to
continue this cost-effective practice. If sediments are placed on the banks, they will then
become defmed as soils, and be subject to state cl~up standards for soils. Because there is
known contamination in the sediments that could lead to exceedances of these soil standards,
this practice would not be allowed under this alternative. '
Costs for Alternative 1 are:
Capital cost:
Present value of O&M costs:
Total present wonh:
$0
$0
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Engineering Field Activity, Northwest
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CTO 0074
Final Record of Decision
Revision No.: 0
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Page 72 .
9.2 ALTERNATIVE 2 - DITCH REROUTING AND BACKFILLING
This alternative would involve rerouting the existing ditches m segments where contaminated
sediment has been found, so that these sections of the existing ditch network would be .
covered and filled with earth. Covering the contaminated segments with eanh would
eliminate the ecological exposure pathway of concern for Area 16. Risk to ecological
receptors is typically considered only to depths of 2 feet (depth of burrowing animals), and
covering the sediment with more than 2 feet of earth would essentially eliminate the exposure
. route for animals such as voles, shrews; and muskrats. .
Covering the sediments would convert them to soils that could pose. a human health risk to
' future residents, or might pose ecological risks, if the soils were exposed by future .
excavation. Because of this, Alternative 2 would include institutional controls in the form of
land use restrictions to prevent future excavation. The institutional controls would document
the locations of the filled ditches and prevent land use or future activity that would disturb .
these locations.. . ,
, , ,
Acti()lls for this alternative would include additional in situ samplirig of the ditch'sedimeilt '
near sample stations that showed evidence of contamination during the remedial investigation,
const!Uction of new ditches around the areas of contamination, and backfilling the existing
ditches with excavated soil. ' ,
The sam'pIing result's would be used to verify the dimensions of existing ditch segments that
would be filled and the length and configuration of new ditch segments needed to replace
them. If contamination is detected at consecutive sampling points, all the sedime,nts between
those points would be remediated.' ...
Segments of new drainage ditch would be constructed with conventional excavation
equipment. '111e new ditch segments would mirror the existing ditch, and material excavated,
. from the new ditches would be used as backfill for placement into the existing ditch sections.
In limited places where the ends of a new ditch segment would need to be tied into an
existing ditch near a baffle or culven. it may be necessary to remove contaminated sediments
from the ends' of the existing ditch segment rather than simply coveriDg them with backf"'Ill.
In such cases,. the contaminated seqiments would be dredged and .placed' in the center of the
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NAS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract.
, Engineering Field Activity. Northwest
Contract No. N62474-89-D-9295
CTO 0074
Final Record of Decision
Revision No.: 0
, Date: 03/29/95
Page 73
Estimated costs for Alternative 2 are:
Capital cost: .
Present value of O&M costs:
Total present worth:
$0.6 million
$0
$0.6 million
These costs were ~stimated based on remediation of the ditch segments selected for..
evaluation in the FS. These segments .were' selected by comparing the RI data for ditch
sediments to the preliminary remediation goals developed in the FS, and identifying ditch
locations of greatest ecological concern. Because the preliminary remediation goals in the FS
were different from the fmal cleanup levels presented in Section 8, the FS costs were based
on several additional ditch segments ~yond those selected for fmal remediation in Section 8
. and shown in Figure 8-1. The additiona,l ditch segments included in the FS cost estimates
w~re at statipns 16-9, 16-31, and 16-32. Two of these stations are located near the heron
rookery (Figure 6-3).
, Because presently available data for estimating the extent of the ditch contaminants are
limited; the actual scope of the remedial actions is unknown at this time. The actual length
and configuration of ditch segments that would be filled and replaced would be detennined
based on the sampling described earlier. .
9.3 ALTERNATIVE 3 - SEDIMENT REMOVAL AND DISPOSAL
This alternative would involve removal and disposal of sedinients .in the runway ditches
where contaminated sediment. has been found. Removing the con~ted sediments would
eliminate the ecological exposure pathway of concern for Area 16, and reduce possible
human health risks that may occur if contaminated sediments were dredged in the future for
maintenance reasons and placed on the ditch banks.
. Actions for this alternative would include in situ sampling of the ditch sediment near the
sample locations that showed evidence of cont.amination during the remedial investigation,
excavation or dredging of. sediments, and appropriate disposal of the dredged. materials. It
. was assumed that sediment removal would be canied out for the same ditch segments.
selected for remedial actipn in Alternative 2 (Figure 8-1). The rationale for the selected
, ditch segments is the same as in Alternative 2. The in situ sampling would be performed
during the design phase to verify the extent of dredging that would be required at each ditch
segment. If contamination is detected at consecutive sampling points, a,J..l sediments betWeen
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NAS WHIDBEY ISLAND, OPERABLE UNIT 3
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EApDeering Field Activity, Northwest
Coatnct No. N62474-89-D-9295
CTO 0074
Final Record of Decision.
Revision No.: 0
Date: 03/29/95
Page 74.
It was' assumed in the feasibility study that the in situ sampling would also be used to
determine whether the removed material will be classified as a hazardous waste, and to select
appropriate means for disposal (e.g., whether treatment or disposal in a Subtitle C landfill
would be required). For h3zardous waste profiling pUi'pQses, it was assumed that the
samples would be analyzed for toxicity characteristic leaching procedure (TCLP) constituents
(40 CFR 261.24[b], Appendix II). Since the sediments are not expected to display the
characteristics of ignitability, corrosivity, or. reactivity, the assessment of the toxicity.
d1~ra~teristic would therefore detennine whether or not the soil meets the hazardous waste'
cntena. .
Removal of Area 16 ditch sediments would be done by mechanical dredging. The total
quantity of dredged material was estimated to be 3,700 cubic yards, with an average depth of
about 2 feet. Dredging operations would be conducted during the dry season and would be
scheduled to minimize impacts to the nonhern harrier .population.
Depending on the results of the in situ sampling, the dredged sediments would be transponed
to either a hazardous waste landfill or a nonhazardous waste landfill for disposal. Based on
RI sediment data, little or none of the. dredged material is . likely to be. classified as a '.
hazardous. or dangerous waste. Accordingly, it was assumed for the purpose of this
alternative that 95 percent of the dredged sediments would pass the hazardous waste criteria
and thus could be disposed as nonhazardous waste. The nonhazardous waste would be .
placed at the Area 6 landfill and then covered by a cap, which is part of the selected remedy.
for the cleanup of OU 1. It was assumed that the other 5 percent of dredged sediments
would need to be treated as a hazardous waste and be disposed at an approved off-site
Subtitle C landfill. These assumed percentages have a significant effect. on the estimated cost
for this alternative. . . The. in situ sampling during the design phase would verify these
assumptions prior to implementation. ..
The estimated costs for Alternative 3.are:.
. .
Capital cost:
Present value of O&M costs:
Total present worth:
$0.6 to 1.2 million
$0
$0.6 to 1.2 million
These costs were estimated' based on remediation of the ditch segments selected for
evaluation in the FS. This included several additional ditch segments beyond those shown in
Figure 8-1, for the reasons exp.1ained earlier for Alternative 2. ..
The cost ranges shown above are dependent upon the extent of sampling and dredging effon
that would be .required. The lower range cost reflects optimistic assumptions for dredging
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NAS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
, Engineering Field Activity. Northwest
Contract No. N62474-89-D-9295 '
CTO 0074
Final Record of Decision'
Revision No.: 0
Date: 03/29/95
, Page 75
If the in situ sampling indicates a significant portion of the sediments are hazardous wastes,
additional sampling may be appropriate to better defme the extent of the sediments that
require hazardous waste management, to avoid unnecessary disposal costs. Such additional
, sampling and less optimistic sediment handling assumptions are 'reflected in the upper range
cost.' '
10.0 COMPARATIVE ANALYSIS OF ALTERNATIVES
EP A has establi.shed nine criteria for the evaluation of remedial alternatives:
.
.
.
, .
.
.
.
.
.
Overall protection of human health and the environment
Complianc.e with ARARs
Long-tenn effectiveness and pennanence
Reduction of toxicity, mobility,. and volume through treatment
'Shon-tenn effectiveness
Implementability
Cost
State acceptance
,Community acceptance
The following sections summarize the detailed evaluation of alternatives presented in the
feasibility study. Each remedial alternative is discussed relative to, the evaluation criteria, to
,help, identify'a preferred alternative.' , ,
10.1 OVERALL ,PROTECTION OF,HUMAN HEALm AND THE ENVIRONMENT '
, Because there was no unacceptable risk to humans, all of the alternatives would be protective
of human health. Adverse ecological risks were identified for muskrats and benthic
organisms living in contact with contaminated sediments in the runway ditches.
Alternative ,3 would provide the highest level of protectlonto the environment by removing
the contaminated materials to a location that will contain the contaminated sediments and
prevent exposures 'of concern. Because the RI data indicate the contaminants in the ,
sediments are below hazardous waste levels, it is expected most of the dredged material can
be readily and safely disposed at the on-site Area 6 landfill prior to its being capped as pan
of the remedial actions selected for au 1. The sediments will be analyzed prior to dredging
tQ detennine if any are classified as hazardous waste which require treatment prior to .
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NAS WHIDBEY ISLAND. OPERABLE UNIT 3
U. S. Navy - CLEAN Contract
Engineering Field Activity. Northwest
Contract No. N62474-89-D-9295
CTO 0074
Fin~ Record of Decision
Revision No.: b
Date: 03/29/95
Page 76 .
provide additional protection compared with the other alternatives through reduction of
toxicity, mobility or volume of contaminants.
Alternative I (the no-action alternative) would not prevent exposures of concern and is not
protective of the environment. In addition, under this alternative, the Navy would be unable
to perfonn necessary routine maintenance of the runway ditches in the future. Because
Alternative 1 would not provide adequate overa1l.protection of the environment and does not. .
meet this threshold criterion, it is eliminated from funher consideration and is not included in
. the following sections 'that discuss the remaining evaluation criteria. .
Alternative.2 would eliminate ecological risks by covering the contaminated ditch sedirne~ts,.
thereby preventing organisms such as muskrats from being exposed to the contaminated
sediments. However, the contaminated material would not be removed from the site, and
these substances could be exposed if the covered areas were excavated in the future. This
alternative would rely on institutional controls. to prevent future excavation in places where
sediments are covered.
10.2 COMPLIANCE WITH APPLICABLE OR RELEVANT AND APPROPRIATE
REQUIREMENTS (ARARS) .
No chemical-specific ARARs were identified for the runway ditch sediments, so compliance
with this criterion would be equally met by all of the alternatives. On the other hand, non-
promulgated chemical criteria, which constitute guidance "to be considered" (TBC), were
identified in the baseline risk assessment and were considered in the development of '.
preliminary remediation goals for evaluating alternatives in the FS. The TBCs would be met
. t6 an equivalent degree by'Alternatives 2 and 3, either by covering the material of concern .
so that it no longer is present as sediment, or by dredging to remove the material from the
site. Although theseTBCs were used tQ develop Cleanup levels, they are unenforceable
guidelines, and compliance with them is not mandatory.
Although under Alternative 2 the contaminants would be covered with soil, they would be
left at the site. However, once the sediments are covered, they become soils, and some of.
the con~inants would then. exceed state cleanup levels for soils. Although state cleanup.
levels. would be exceeded, state requirements could be met because the soil cover and
institution31 controls would control the potential human exposures on' which' the 'cleanup.
levels are based. . .
It is anticipated that compliance with location- and action-specific ARARs could be achieved
for all of the alternatives. Consultation with a number of regulatory agencies (wetlands,
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N AS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
Engineering Field Activity, Northwest
Con.tract No. N62414-89-D-9295
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Revision No.: 0
Date:, 03/29/95
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substantive elements of location- and action-speciiic ARARs were met. On-site construction
equipment and activities would be very similar for Altematives,2 and 3. Alternative 2,
however, might be viewed less favorably by these regulatory agencies, because it would
invol've filling as well as dredging and because it may involve more extensive clearing than '
Alternative 3 in order to construct the new ditches. '
10.3, LONG-TERM EFFECTIVENESS
, Alterna~ve 2 would be effective over the long-term in preventing ecological exposures of
concern, provided that the soil cover is not disturbed by future construction activity.
Alternative 2 would not provide as permanent a remedy as Alternative 3 because the '
contaminants would be left ,at the site rather than removed, and institutional controls would
be relied on to prevent disturbance of the cover.
, ,
Alterrultive 3 offers betterlong-tenn effectiveness because it ,would 'permanently remove tge
co'ntaminated sediritents to another location. These sediments would be covered with an
impermeable cap during closure of the Area 6 landfill (or an off~site landfill if one is used).
10.4 .REDUCTION OF TOXICITY, MOBll.JTY, OR VOLt,1ME THROUGH
TREATMENT '
The need for treatment' was considered for the contaminated sediments. However. based on
the, chemical concentrations detected' in the iu sediment samples,. it is believed that testing
during remedial design will not result in the contaminated sediment being designated as a
dangerous or hazardous waste. If this is so, treatment will not be required for disposal. The
need for and degree of required treatment depends on whether the material to be disposed has
acceptable concentrations of chemicals compared with criteria defmed in hazardous and
dangerous waste regulations. The RI results for the ditch sediments were compared to these
criteria, and it was determined that no treatment would be required prior to disposal and that
, concentrations are low enough that treatment is not necessary for overall protection of human
health and t~e environment. Therefore, there was n~ reason to eval~te treatment
alternatives and none of the alternatives satisfy this evaluation criterion. '
10.5 SHORT-TERM EFFECTIVENESS
None'of the alternatives would likely pose health risks during implementation. Workers and
nearby residents would be protected during construction by engineering and safety controls.
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Engineering Field Activity. Northwest
Contract No. N62474-89-D-9295
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Revision No.: 0
Date: 03/29/95
Page 78
and divening stonnwater during constru~tion activities, in order.to confme impacts to the. .
segments being remediated. Alternatives 2 and 3 would both achieve remedial action
objectives in a similar time frame. This may take up to a year, because work around the
ditches could only be accomplished during the dry season. Remedial action objectives would
be met in Alternative 2 by containment and institutional controls, although contaminants
would .remain at Area 16. For Alternative 3, cleanup levels would be achieved in the ditches
because contaminated sediments would be removed and disposed in 'a controlled landfIll. .
Unavoidable short-term ecological impacts would occur to a similar degree under both
Alternative 2 and Alternative 3; these include temporary disruption of habitat and destruction
of existing benthic organisms. In either case, it is expected that the benthic organisms would
repopulate and establish a healthier community. .
10.6 IMPLEMENTABILITY
Alternative 3 would present some Navy flightline operational concerns at Ault Field as a
result of work in the ditches around the runways and taxiways. Rocks or dirt could fall onto
the taXiways from trucks hauling excavated sediments to the disPosal site; this would present
severe safety hazards to aircraft and pilots because debris could be sucked into the aircraft
. engines. Therefore, coordination with airfield operations staff would be required. For
example, the flight operations would have to be suspended while dredged material is hauled .
. out of the infield area as trucks cross the taxiways and runways. . Because the infield area is
. 'completely surrounded by taxiways and runways, there is no alternative route for removing
the material that would avoid temporary suspension of flight operations.
These flightline concerns would be less important for Alternative 2.' There would be'less
risk to aircraft arid crew. from foreign objects or debris being picked up by the aircraft .
engines, because Altentative 2 does not involve hauling sediments across the runways.
Another consideration for Alternarlve 3 is that. the tuning of the dredging and disposal of
sediments must.be coordinated with the Area 6 landfill capping to ensure that the sedilIients
are disposed before the fmal cap is constructed. A delay in the schedule for the au 3 could
cause a delay in the schedule for capping the landfill. Coordination with the Area 6 landfill
closure is important because the costs for.Alternative 3 would be substantially higher if an
off-site landfill must be used. .
. .
Alternatives 2 and 3 would both be easy to implement from a construction standpoint. Both
alternatives involve straightforward application of common construction equipment.
However, the other factors described above would make Altema~ive 3 harder to implement
than Alternative 2. Alternatives 2 and 3 would both require an environmental protection plan
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NAS WlDDBEY ISLAND. OPERABLE UNIT 3
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Contract No. N62474-89-D':9295
CTO 0074
Final Record of Decision
Revision No.: 0
Date: 03/29/95
Page 79
. 10.7 COST
The estimated present worth cost of Alternative 2 is $0.6 million. The esnmated present
wonh cost for Alternative 3 ranges between $0.6 and $1.2 million, depending on the extent
of sampling and dredging effort that would be required for implementation. . The cost of
Alternative 3 could be substantially higher if design phase sampling show~ the sediments
must be treated or disposed as a hazardous waste. However, if the design phase sampling
confmns the fmdings of the RI,. the sediments will not need to be treated or disposed off site,'
and the cost of Alternative 3 would be comparable to that of Alternative 2.
The cost estimates were prepared using costing techniques that typically ~chieve an accuracy.
, of "+ 50 percent to. - 30 percent for a specifi~ scope of actions. Additional uncertainty in the
costs is introduced by variations in the volumes and other quantities assumed for the
estimates.
10.8 STATE ACCEPrANCE
Ecology has been involved with the oversight and review of the remedial investigation (URS
1994a), feasibility study (URS 1994b), and proposed plan (URS I 994c). Ecology comments
have, resulted in substantive changes to these documents: .
10.9 COMMUNITY ACCEPTANCE
On July 26, 1994, the Na~ held an open house and a public meeting to discuss the proposed
plan for final action at OU 3. The proposed plan identified Alternative 3 as the preferred
alternative for OU 3, and discussed the other alternatives being considered. The results of
the public meeting indicated that community members generally supported the Navy's
preferred alternative for remed_g the runway ditches. However, some community
members submitted comments that did not suppon the proposed plan. One commenter
wanted the Navy to take no action, while another felt the Navy should do. more than any of
the alternatives presented in the proposed plan.
A responsiveness summary, which addresses questions and comments received during the
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NAS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
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Contract No. N62474-89-D-929S
"CTO 0074
Final Record of Decision".
Revision No.: 0
Date: 03/29/95
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11.0 THE SELECTED REMEDY
The Navy has chosen Alternative 3 (sediment removal and disposal) as the selected remedy
to mitigate current ecological risks associated with the runway ditch sediments and
hypothetical human health risks if they are dredged in the future for maintenance. Removing
sediments from those segments of the ditch where contaminants have been found that
.cootribute.to unacceptable risk and placing the dredged sediments under the cover of the
Area 6 landfill (or in an off-site Subtitle C landfill) will accomplish the objective of
protecting human health and the environment.
The major components of the selected remedy include the following actions:.
.
" .
Sample and analyze sediment.s in the ditch segments identified as
contaminated during the" remedial investigation, to determine the
extent of contamination that needs to be removed.
.
Compare the sample results to RCRA criteria for toxicity
characteristic wastes (i.e., TCLP criteria in 40 CFR 261.24) to
determine whether the sediments to be dredged will need to be
treated and disposed as a hazardous waste or dangerous waste.
Initially, this comparison will be done using the total
. concentrations detected" in the sediment samples (rather than
leachate concentrations), divided by a factor of 20 to account for
the 20-fold dilution that occurs in the TCLP test. If any sample"
fails the TCLP criteria based on this initial approach,
resampling and reanalysis using the TCLP test will be . .
considered to obtain actual leachate results for comparison with .
the TCLP criteria. .
.
Dredge the sediments from those ponions of the ditch segments'
determined by the sampling to be contaminated in comparison
with the selected cleanup levels shown in Table 8-1.
.: . For those sed~m~nts determined to be non-h~ous waste~ haul'
the dredged sediments to the Area 6 landfill and place thein so '
they will be under the fmal cover system when it is completed.
.
.
For any sediments determined to be hazardous waste. haul the
dredged sediments to a permitted off-site facility for appropriate
-------
NAS WHIDBEY.ISLAND: OPERABLE UNIT 3
U.S. Navy - CLEAN Contract '
Engineering Field Activity, Northwest
Contract, No. N62474-89-D-9295
CTO 0074
Final Record of Decision
Revision No.: 0
Date: 03/29/95
Page 8 1
The above. actions will be carried out for those s~gments of the runway ditches identified in
Section 8 (Figure 8-1). These actions will require an environmental protection plan to
prevent degradation of water quality during remediation. The actions are based on the'
cleanup levels described in Section 8.1.3, which include MTCA, C industrial soil cleanup
, levels with the assumption that land use at the ditches \yill remain industrial (non-residential) ,
in the future. If future land use changes to non-industrial activity, these cleanup 'levels and
actions will be reevaluated. "
The Navy sampled the ditches in January 1995. Based on preliminary results, the entire
length of the ditch segments identified in this ROD. for potential remedial action wiU require
cleanup. Conf'mnation of these results will be, made in consultation with EPA.
u.o STATUTORY DETERMINATIONS
'. . .
Under CERCLA Section 121, selected remedies must be' protective of human health and the
environment, comply with ARARs, be cost-effective, and use permanent solutions and
alternative treatment technologies to the maximum extent practical. In addition, CERCLA
includeS a preference for remedies that use treatment that significantly reduces volume,
toxicity, or mobility of hazardous 'wastes as their principal element. How the selected
remedy for Area 16 meets these statutory requirements is discussed in the following sections.
, ,
12.1 PROTECTION OF HUMAN HEALm AND THE ENVIRONMENT
The selected remedial action for ,Area 16 will protect human health and the environment
through sediment removal and disposal actions. Implementation of these remedial actions
will not pose unacceptable short-teon risks to site workers or nearby residents. Placement of
the dredged sediments under the cap of the Area 6 landfill '(or an off-site hazardous waste
landfill) wHl prevent direct exposure to contaminants by ecological receptors.
The ,selected remedy corresponds with. Alternative 3 ~f the feasibility study. ' This alternative
is preferred over the other alternatives that were evaluated because it will result in a more
permanent solution for au 3. Unlike the other alternatives, the selected remedy will remove
the contaminants of concern from Area 16 and provide effective, long-term containment of
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NAS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
Engineering Field Activity. Northwest
Contract No. N62474-89-D-9295
CTO 0074 '
Final Record of Decision', .
Revision No.: 0
Date: 03/29/95
Page 82
U.2 COMPLIANCE WITH ARARS
The selected remedy for area 16 will comply with federal and state ARARs that have been
identified. No waiver of any ARAR ,IS being sought or invoked for any component of the,
selected remedies. The ARARs identified for OU 3 are discussed in the following sections.
U.2.1 Chemical-S~ific ARARs
, ,
There are no chemical-specific standards that are considered ARARs for the freshwater
sediments in the Area 16 runway ditches.
U.2.2 Location-Specific ARARs
.
Federal Executive Order 11990, 40 CFR ,Part 6, Appendix A is applicable to
, the actions that may affect the wetlands .at Area 16.',' ,
.
The Endangered Species Act (16 USC U531 promulgated by 33 CFR ~~320-
330) is relevant and appropriate to Ault' Field in general, because several birds
and plants listed as sensitive or threatened species are known to inhabit-the
base. However, the actions of the selected remedy at Area 16 will not affect
critical habitat of these species. '
U.2.3 Action-Specific~.
.
Section 404 of the Clean Water Act ' (Federal Water Pollution Control Act, 33
USC'~~1344 promulgated by 33 CFR n320-330 and 40 CFR ~230), which'
requires the minimization and mitigation of impacts due to unavoidable
dredging or filling activities in navigable waters including wetlands, is
applicable to the dredging activities of the selected remedy at Area 16.
.
Federal Resource Conservation and Recovery Act (regulations set fonh'in 40
. CFR ~~261, 262~ 263,- and 268), which specijies waste identification, storage,
manifest, transpon, treatment, and disposal requiremem~ ror solid waste that
may contain hazardous substances, is applicable to the ditch sediments that will
be dredged during remediation of Area 16.
.
State of Washin.gton Dangerous Waste Regulations (WAC 17-3-303'), which
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NAS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract.
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0074 .
Final Record of Decision
Revision No.: 0
Date: 03/29/95
Page 83
. disposal requirements for solid waste that may contain hazardous substanCes, is
applicable to the ditch sediments that will be dredged during remediation of
Area 16.
.
Federal Clean Air Act General Provisions (40 CFR ~52) and Puget Sound Air
Pollution Control Authority (PSAPCA) Regulation 1, Section 9.15 for the .
. control of fugitive dust during construction activities, is applicable to the ditch.
'sediment removal and disposal actions of the selected remedy.
12.2.4 Other Criteria, Advisories, or Guidance
This section discusses other criteria, advisories, or guidances that are considered to be
appropriate for the remedial actions of the selected remedy for Area 16.
'. If any of the ditch sediments dredged during remediation of Area 16 are detennined to be
hazardous wastes that must be disposed in an off-site RCRA Subtitle C landfI1,1, the NCP off-
site disposal rule (40 CPR ~300.440) must be followed. This will require that the Navy
. obtain prior certification from EP A that any off-site landfill to be used for this purpose is in
compliance with RCRA regulations stipulated by the off-site disposal rule.
As discussed in Section 8.1.3, industrial soil cleanup levels of the State of Washington Model
Toxics Control Act (MTCA; Chapter 70.105D RCW) as codified in Chapter 173-340 WAC
were used as guidance for developing cleanup levels for the ditch sediments at Area 16. .
These cleanup leve~s are considered t~ be guidance rather than ARARs because they apply to
remediation of soil rather than sediments under MTCA. . .
12.3 COST-EFFECTIVENESS
The selected remedy for Area 16 is cost-effective because it has been determined to provide
overall effectiveness proportional to its cost, with an estimated present worth cost of $0.6 to
$1.2 million. This range in cost reflects different assumptions regarding the extent of
, sampling and dredging effort tbat will be needed. ]f remedial design phase sampling
confmns the fmdings of the RI, it is anticipated that the cost of the selected alternative would
be comparable to that of Alternative 2, which was estimated to. have a present worth cost of
. ,$0.6 million.
Although the upper range of the estimated cost for the selected remedy indicates that it could
b~ twice as expensive as Alternative 2, it would provide a solution ~ith much better long-
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:\ AS WHIDBEY ISLAND. OPERABLE UNIT 3
l' . S :'\a\')' - CLEAN Contract
Engmeering Field Activity. Northwest
Cocwa::l No. N62474-89-D-9295
CTO 0074
Final ~ec()rd of DeCision ...
Revision No.: 0
Date: 03/29/95
Page 84
the runway ditches and' contained in a' controlled landfill rather than just being cove~ and
left in place and covered with soil to prevent exposures.
Although the selected remedy has a number of implementation difficulties associated with
flightline operations that would be avoided in Alternative 2, the Navy has detennined that
these difficulties are not critical constraints, and they can be accommodated in the interest of
achieving a more protective and pennanent remedial action.
. The cost of the selected remedy could be substantially higher if the remedial design phase.
sampling shows that a significant portion of the sediments must be treated or disposed as a
hazardous waste. Should this occur, the .cost-effectiveness of the selected remedy could be
reevaluated. As discussed earlier, the RI sediment data suggest that this is not very likely.
U.4 UTILIZATION OF PERMANENT SOLUTIONS AND TREATMENT
TECHNOLOGIES TO THE MAXIMUM EXTENT PRACTICAL
The selected remedy. represents the maximum 'extent to which pennanent solutions and .
treatment technologies can be utilized in a cost-effective manner for Area 16. It is protective
of human health and the environment, complies with ARARs, and provides the best balance
of tradeoffs in terms of long-term effectiveness, permanence, short-term effectiveness,
implementability, cost, and reductions in toxicity, mobility, or volume achieved through
treatment. The selected remedy meets the statutory req1,1irement to use permanent solutions'
to the maximum practical extent. The dredged sediments will be placed in a controlled on-
site landfill (Area 6) and will be co.vered by an impermeable liner when the landfill is
capped. This will provide for practical, permanent containment of the c'ontaminated
sediments; because the contaminants in sediments are relatively immobile chemicals (i.e.,
strongly sorbed), .additional measures to reduce mobility would not be cost-effective.
In selecting the preferred remedy from the alt~matives evaluated. long-tenn effectiveness was
the most important non-threshold (balancing) criterion. By removing the contaminants from
the runway ditches, the selectetl remedy will provide a much more permanent solution for
au 3 than would Alternative 2.. Sediment removal and disposal in the Area 6 landfill (or an
off-site hazardous waste landfill if needed for the more contaminated sediments) will provide
more effective, long-term containment of the contaminat~ material than leaving th~ .
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NAS WHIDBEY ISLAND, OPERABLE UNIT 3
U.S. Navy - CLEAN Contract'
, . Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0074
Final Record of Decision
Revision No.: 0
Date: 03/29/95
Page 85
;l2.S PREFERENCE. FOR TREATMENT AS APRJNCIPAL, ELEMENT
The selected remedy is not expected to meet the statutory preference for selecting remedial
,actions that employ treatment technologies to pennanently and,signiijcantly reduCe the
toxicity, mobility, or volume of the hazardous substances as a, principal element. Although
the selected remedy will include off-site treatment of dredged sediments if this is necessary to
bring chemical concentrations into compliance with hazardous waste disposal regulations; this
treatmen~ is not expected to be needed for the majority of the sediments and it would not
reduce the mobility, toxicity, or volume of hazardous residuals left at the site.
Because 'of the wide range of chemical types detected in the sediments, and their relatively
low concentrations in comparison wit~ hazardous waste designation criteria, treatment
processes are not expected to be cost-effective tor the bulk of the sediments that will be
remediated. It is anticipa.ted that a small portion of the sediments may have high
concentrations of contaminants for which treatment may be required ~d effective. ,Off-site
treatment, as included in the selected remedy, will' be the most cost-effective approach for
,the small quantities that are expected. '
13.0 DOCUMENTATION OF SIGNIFICANT CHANGES
The proposed plan, released for public comment in July 1994, discussed remedial action
. altemati~es for both Area 16 and Area 31. The proposed plan identified Alternative 3 as, the,
, preferred alternative for Area 16,' Th~ Navy reviewed all written and verbal comments
submitted during the public comment period for Area 16. Upon review of these comments,
it was determined that no significant changes to the remedy for Area 16, as it was' originally
identified in the proposed plan, were necessary to satisfy public concerns. However, the
preferred alternative has been slightly modified for a different reason. Although the overall
concept of the preferred alternative and the remedial technolQgies to be used have remained
the same, one of the ditch sediment stations identified for remediation in the proposed plan '
,has not been retained for remediation in the selected remedy.
The sediment station that has been deleted from the rememaI action is station '16-32~ This
station had been included among the ditch segments to be remediated in the proposed plan,
based on the prelirilinary remediation goals listed in the FS Report. Based on the flnal
cleanup levels presented in Section 8, remediation of station 16-32 is no longer considered to
be necessary. The rationale for this decision is detailed in Section 8. Removing station 16-
32 represents a change to a component of the prefeITed alternative. Because trees and shnibs
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NAS WHIDBEY ISLAND. OPERABLE UNIT 3
U;S. Navy - CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0074
Final Record of Decision
Revision No.: 0
Date: 03/29/95
Page 86
significant environmental damage compared with the small reduction in risk that would be
achieved by removing the sediments. . .
In response to public comments, the need for remedial action at Area 31 will be reevaluated
based on further characte~tion of the site. In order to allow more time for the
reevaluation of Area 31 while proceeding with a decision for Area 16, Area 31 has been
removed from OU 3. Area 31 will be incorporated into the decision process and the ROD
for OU 5. Removing Area 31 from OU 3 represents a significant change compared with t~t
proposed plan. At the present time, the Navy has not fonnulated a revised preferred
alternative for Area 31, so it is premature to evaluate the significance of changes that may
occur to the remedy for Area 31. .
14.0 RESULTS OF THE HAZARDOUS WASTE. EV!\LUATION STUDY
Operable units for NAS Whidbey Island were 'created when the Navy entered into a federal
facility agreement (FFA) with the Washington Department of Ecology' and EPA in .
September, 1990. At that time, 26 areas scattered throughout NAS Whidbey Island (both
. AultField and the Seaplane Base) that were not included in the operable units were identified
as possible areas of contamination. However. very little was known about these areas. As
part Qf the FFA, tpe Navy agreed to perform -a screening-level investigation known as the
"Hazardous Waste Evaluation Study." This stiJdy was designed to determine whether
sufficient contamination existed to warraJ1t funher investigation, some type of remedial .
action, or no action at any or all of the 26 study areas. The locations of these areas are
shown in Figure: 14.;.1.. . .
. . .
Table 14-1 shows the results of the Hazardous Waste Evaluation Study. This table lists the
.areas that were investigated, the. results of the inve~tigation, and the decision made' for each
study area. For each of the areas, soil and groundwater samples were collected., The results
of the sampling were evaluated against standard Superfund exposure assumptions for .
residential use at a 10-6 or lower cancer risk level, state cleanup levels (MTCA Method B),
and background levels to determine if cleanup actions were necessary.' .
Results of the study indicit.t~ that two of the areas require funher investigation. and potential .
remedial action. Therefore; the. Navy created a new operable unit (OU 5) that consists' of the
Area 1 Beach Landfill and the Area 52 Jet Engine Test Cell. In addition, in 8 of the study.
areas, the Navy will conduct limited removal actions ranging from . removal of site structures
to extraction of floating oil in groundwater. The remaining 16 study areas were found to be
clean and require no funher action. None of the 26 study areas is a RCRA-related unit.
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/;-~
. l,iT~~\l\ """
~.I ~ '\ \ "
.ji ./ / '\, ----_.r----~ ~?
/ J: '.\ I .::.
i~=~~~t1I--~--J J
~,.~~\ : \ ~: ~ . '. 1
~t.~ CRESCSfrI/ARBOR \ r--
:I( OAKHARBOR\S.' ..~:~sri' ~'i
~."~ !
I ... / PoinelfPt" .
! AfsJIor Pt
!
l
I:
STRAIT OF.
JUAN DEFUCA
i
. ,.
/ .
,,/
// ,.
~" DUGUAUA
. . "0' BAYp i
. Clover Valley Lagoon ~ I .
~.
---
I
'1
, - Base Boundary
3~ Area Locations
~~z~ 0
"-1 Scale In Miles
CLEAN. .
COMPREHENSIVE LONG-
TERM ENVIRONMENTAL
. ACTION NAVY
. '
. Figure 14-1
Locations of Hazardous Waste
, Evaluation Study Areas
CTO 0074
NAS WHIDBEY ISLAND, WA .
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NAS WHIDBEY ISLAND, OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
Engineering field Activity, Northwest
. Contract No. N62474-89-D-9295
CTO 0074
Table '14-1
Disposition of Hazardous Waste Evaluation Study Areas
final Record of Decision
Revision No.: 0
Date: 03/29/95
Page 88
H" """"0 ..... . ..... n.. ...... .. . . . u.. .. n..... ..... n. ....... .
:::::'i."~:.Wli::lij~Ii::::' :"'.::::::lli::INmllll~I:;::;::;;,.I:
:':::(':;:::::':::;:;;:;;::';::;!:i=:==:::@,?::t::)/\r:::,?::":::::::::'::::"::::::'~~'Jtmm!mffl:':..::'::::::.:,::::I'
Area I - Beach Landfm
Contaminated Soils/Sedimenls
,Ero,ding into Marine Envirunm"nl
Area 7 - Old 'Waste Storage Tank
Spills
Contaminated Soil and OW from
Past Spills
.Area 8 - Sewage Sludge Disposal
Area .
Soils Contaminated by inorganics
Concentrated in Sludges
Area 9 - Asphalt Planl Disposal Area
Contaminated Soils
Area 10 - Bldg, 2536, PCP Dip
Tank
Contaminated Soils from Spills
Area II - Fuel Farm 4
Soils and OW Contaminated by
Tank Cleaning Byproducl!
Area 13 - Fuel Farm 3
Soils and OW Contaminated by
Ta':lk Cleaning Byproducls
Area IS - PD-680 Spill
Spill. Leaks from HW Storage
Tank
Area 17 - Old Ault Field Cual Pile
Soil and OW Contaminated b)' Pile
Leachate .
Soil, Sediment, OW/VOCs,
PAHs; Peslicid"s, Melals
Soil; OW/VOCI!, SVOCs,
Inorganics ' .
Soilllnorganics
Soil, Sediment, Surface.
WaterIVOCs, SVOCs
SoillSVOCs, PCBs
Soil; OWllnorganics, VOCs,
SVOCs, Pesticides, PCBs
Soil, OWllnorganics, VOCs,
SVOCs, Pesticides, PCBs
Soil, SedimentlVOCs, SVOCs
SoillSVOCs, Inorganics.
DDT, PCBs in Sed. < MTCA,
Metals iit OW > MTCA
OW Inorganics Comparable to
Background levels
Soil Inorganics Comparable to
Background
'Inorganics at Background,
Phlhalates Aliributed to Lab
No Detection
VOCs In Soil, OW < MTCA
Inorganics = Background
VOCs in 80il.< MTCA,
Lead> RBSCs,
Free Product Present
PAHs, DDE in Sed. < RBSCs
Inorganics Comparable to
Background,
'SVOCs
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N.~S WHIDBEY ISLAND, OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
Engin~ring Field Activity, Northwest.
Contract No. N62474-89-D-929S
CTO 0074
Area 18 . Aull Field Nose Hangn
Area 19. Fuel Truck Depol
Area 20 - Aull Fil'ld Sewage
Clarilier
Area 22 . Hangar S
Area 23 .North~est Apron-Area
Area 24 - Bldg. 283, pcp Dip
Area 25 - Bldg. 120, Xfonner Area
Area 27 - 1966 Fire School
Area 28 . Chapel Fire School
Area 32 . BIo',. 889, Tran.furmer
SCrvl~C Ar..
Table 14-1 (Continued)
Disposition of Hazardous Waste Evaluation Study Areas
Final Record of Decision
Revision No.: 0
Date: 03/29/95
Page 89
!lii!I.li!lli:ili~I~liiljll~ili!::li!liIIIJIIIIr,~1111'1~!I'lllil!!'li
Soils and OW Contaminated by
Aircraft t.tlinlenance Operation~
- Pelroleum .Conlaminaled Soils
Soils and OW Contaminaled by
Waslewater Tank Leakage
Soil and OW Conlaminaled by
Aircraft Mainlenance Operalion~
Conlaminaled Soils/Sedimenls
Eroding inlo Marine Environmenl
Contaminated Soil.from Past Spill.
Soils Conlaminaled by PCBs
Soil. and OW Contaminated wilh
Unburned Fuel. and Solvenls
Soils and OW Conlaminaled wilh
Unburned Fuels and Solvents
Migralion of PCB Contaminated
SedlIRClIIlII Strail
Soil, OWl VOCs, SVOCs, PCBs,
Peslicides, Inorganies
.SoillTotal Pelroleum Hydro.
SoilNOCs, SVOCs, Inorganics
Soil, OWl VOC., SVOCs, PCBs,
Pesticide.. Inorganics, TPH
Soil, Sedimenl, OWNOCa,
PAHa, Peslicides, Melal.
Soil I SVOCs, TPH
Soil/PCBs
SoilNOCs, SVOCs
SoilIVOCs, SVOCs; Peslicides,
PCBs. Inorga"ics
Soil, Sedimenll PCBs.
Inorganics ~omparable 10
Background,
VOC. < RBSC;s
TPH Below MTCA Levels
Organics < MTCA,
Inorganics Comparable 10
Background -
VOCs < MTCA.
Inorganics Comparsble 10
Background
VOCs Delecled < RBSCs
No PCP, TPH < MTCA
No Deleclions
BTEX < MTCA; RBSCs
Organics < MTCA. ROSCs,
OW Inorganics Cumpare 10
. Background'
No Deleelinns
No Further Aclion
No Further AClion
Removal Aclion - Remuve
Abandoned HW SlOrage Tank
No Further Aclion
No Further Aclion
No Further Aclion
No Further AClion
No Further A~lion
No Further Aclion
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NAS WHIDBEY ISLAND, OPERABLE UNIT.3
U.S. Navy - CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295 .
CTO 0074
Area 34 - Machine Oun Range
BemIs
Area 3S - Fuel Fann 2
Mea 36 - Fuel Fann I
Area 40 - Seaplane Base Coal Pile
Area 4S - TCE Tank
Area S2 - Jet Engine Test Cell
'Area S3 .Polnell Poiut Orduance
Area
Table 14-1 (Continued)
Disposition of Hazardous Waste Evaluation Study Areas
.:::;:lali',liiigiiii'ciRM:'
~ii!1!;1~j~i~~~i~~ijj~~~~~ii~ij1~~iiii~~1iiii:!ji1Ji!i~~ii,!iijiii!1[!1iii;:~;!!ili~~!~~/:~~:~?t<:".r!~i~i[;!~::jj~'
.... .
Soils and Sediments Contaminaled
by Oun Cleaning 'Solvents
Soils and OW Contaminaled by
Tank. Cleaning Byproduci.
Soils and OW Conlaminaled by
Tank Cleaning Byproducts .
Soil and OW Contaminated by Pile
Leachate
Soils and OW Contaminated by
Tank Leaks .
Soila and OW Contaminated by
Fuel Leaks and Maint. Activities
Soil Contaminated by Ordnance
RBSC - EPA Risk Based Screening Coucenlrations
TPH . TOlall'etroleum Hydrocarbons
SVOC - Semiv?lalile Organic C.,mpouil\ls
NOTE: BTEX are cunllllon fuel constiluenls.
':::::"::.I::lmmlllll~::::i:::::;'
,:t'::J:::i::.}::::,£g~!mffl~tf.::::'::::::::::::i:i:'i:::::::'
SoilNOCs
Soil, OWllnorganics, VOCs,
SVOCs, Peslicide., PCBs
Soil, OWllnorganics, VOCs,
SVOC., Pesticides, PCBs
Soil/SVOCs, Inorganics
Soil, ow/vaes; SVOCs,
Pesticides, PCBs, 'Inorganics
Soil, OW/VOCs, SVOCs, TPH
Soill Ordnance
PCB 0 Pnlychlurinaled Biphenyls
PAH 0 Polynuclear Aromatic Hydr()carboI15
BT6X 0 Benzene, Totuene, Elhylbenzene, Xylene
Organics < MTCA, RBSCs
Soil Organics < MTCA
OW BTEX > RBSCs
Soil Organics < RBSCs
OW BTEX > ROSCs
Soil SVOCs < RBSCs, MTCA
Inorganics Compare to
Background
Organics < ROSCs, MTCA
OW Inorgal1ics Compsre to
Background
OW Organics> RBSCs, MTCA
Free Product Present
No Detections
Final Record of Decision
Revision No.: 0
Date: 03/29/95
Page 90
.................................-......... "....-....
:1:1111111:11:1'1111111111111/:!::1/11111111,.1111111:11:1!11:11!1!111!:II:I:I!I~!1:1i:
No Further Action
. Removal Action - Close
. Drywells to Prevent Future
Contaminstion
Removal Action - Close
Drywells to Prevent Future
Contamination
No Further Action
Removal Action - Rcmove
Abandoned TCE Tanks
Invcstigate Undcr au S
No Further Action
VOC - Vulatile Organic Compounds
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NAS WHIDBEY rSLAND.OPERABLE UNIT 3
U. S. Navy - CLEAN Contract .
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0074
Final Record of Decision
Revision No.: 0
Date: 03/29/95
Page 91
The planned actions for these 26 study areas ate included in this ROD to fonnally document
the results of the. Hazardous Waste Evaluation Stu<;ly. Detailed infonnation on the sampling
plan and sampling results can be found in the "Final Hazardou~ Waste EvaluatiQn Study
Repon," which is pan of the Administrative Record. The results of the study were presented
in the proposed plan for au 3 and no public comments were received. TheWashington
Depanment of Ecology. was involved. in the scoping and review of the . study and concurs with
the decisions presented in Table 14-1. . .
-------
~f",
APPENDIX A
RESPONSIVENESS SUMMARY
-------
~AS WHIDBEY ISLAND. OPERABLE UNIT 3
. U.S. Navy - CLEAN Contract
. Engineering Field Activity, Northwest
. Contract No. N62474-89-D-9295
CTO 0074
Final Record of Decision.
Revision No.: 0
Date: 03/29/95
Page A-I
APPENDIX A
RESPONSIVENESS SUMMARY
This responsiveness summary addresses public comments on the proposed plan for remedial
action at Naval Air Station (NAS) Whidbey Islai1d, Operable Unit 3 (OU 3). The proposed
plan was reviewed by the public members of the Restoration Advisory Board (RAB), and
their comments were j.ncorporated. mto the proposed plan. !lie public comment period on the
proposed plan was held from July 19, 1994, to August 18, 1994. .
A public meeting was held on July 26, 1994, to present and explain the proposed plan and
solicit public comments. Members of the public and the RAB attended the meeting. During
the meeting all questions ~d comments were recorded by a court reporter. The transcript of
ttp.s meeting was provided to all attendees of the public meeting and is available in the:
Administrative Record. . Questions raised and answers given during the public meeting have
been summarized and are grouped below in the following categories: off-sit,e propenies, .
harrier study, Clover Valley Lagoon, jet fuel residue, ditch dredging, cleanup actions, and
Area 31. .Only two written comments were received on the remedial investigation, feasibility
study, or proposed plan during the public ~omment period.. The responses to these two .
comments are included in this summary.
. AREA 31-FORMER RUNWAY FIRE SCHOOL
Comment 1: The Navy received several comments questioning the need Jor expensive
. cleanup actions at Area 31, the Fonner Runway Fire SchooL Comments indicated that there
was a concern about the cost of cleaning up Area 31 when weighed against the actual risks .
posed by the contamination in this area.
Response 1: The Navy conducred rhe remedial investigation ro derermine rhe nature and
exrenr of conraminarion azlhe site. However, upon rhe discovery of free producr in rhe
groundwazer, the Navy did nor continue to fully define the exact exrent of contam.i1llllion. In
general, EPA has encouraged rhe Navy not to waste .money and time on.funh£r sire
evaluation'once ir.knows rh£re.is lilrely to be a cleanup action in a given area~ The th£ory is
thaI additional sampling to di!.fine rh£ exrent of contamination always rakl!s place during th£ .
remedial design phase of a project. Therefore, there is no need to spend money on
additional sampling during rh£ remedial investigation if it looks lilre rh£re is enough
conramination to warrant a remedial action. The risk in rhis approach is rhat sometimes the
lack of data maJas it difficult ro arrive ar good decisions about rhe type of cleanup action
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NAS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0074
Fuial Record of Decision'
Revision No.: 0
Date: 03/29/95 .
Page A-2,
When allernatives for action were developed for Area 31, the Navy had to make "worst case"
assumptions aboUl the Q1JlOunl of contamination in the soils and groundwarer. COStS for the
allernlllives presenzed in the proposed plan were based on these worst case assumptions
because the Navy did not laww the full extenz of contamination. In addition, after the risk
assessment was completed, it became clear that while there is conzamination in the area,
there are no real currenz risks to human heallh, and only some minor to moderare risks for
small burrowing mammals. However, whereas the risks were not very grear, the estimated,
costs of cleanup were quite high because they were based on assumptions arui unknowns.
, ,
In response to public concerns, EPA and the Navy have decided that additional informmion
is needed before a cleanup decision that makes sense can be issued for Area 31.' Therefore,
Area 31 will no longer be included in OU 3 and will not be included in this ROD. The Navy,
plans to do junher sampling in Area 31 to determine more precisely the amount of
contamination that exists (this additional'sampling would have been done after the ROD,
during the design of the remedial action). On,ce the additional data become available, EPA
and the Navy will be able to re-evaluare Area 31, using more extensive data to make a
decision. .
Area 31 will be included in the OU 5 ROD, which is scheduled for the summer of 1995.
Responses to the comments on the OU 3 proposed plan penaining to Area 31 will be
addressed in the OU 5 ROD. If the Navy recommends a differenr preferred allernarive for
Area 31 based on the new data that will be collected, the public will have a chance to
, comment on any new cleanup alternatives during the public comment period for OU 5.
Comment 2: Because Area 31 was included in the proposeQ plan for au 3, the Navy,
received a number of comments and questions on the proposed cleanup action for Area 31
and on, tlie speCific conditions at this site. The comments focused on the status of the oil '
plume (i.e.~ whether it was migrating); any current or future threats to human health, the'
cost of the preferred alternative, and specific questions about the effects of ,the preferred '
alternative. ' " , ' ,
Response 2: The Navy does not plan to provide responses to all the comments received on
Area 31 at this time. It is not the Navy's intention to ignore the comments that were received
during the public comment period on Area 31. However, as previou#y explained in both the'
text of the ROD and in this responsiv.enesssummary, Area 31 is no longer included in Ot! 3
and therefore; it is not appropriate to address all the previoUs Area '31 corilTTlenrs and' ,
responses to those comments in .this decision document. For some comments, the Navy
simply does not laww the answers because more data are needed before they can be
answered. In addition, it is premature to answer specific comments abOUt the preferred
alternlllive, since a cleanup decision has been pui on hold pending the resulls of additional
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NAS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0074.
Final Record of Decision
Revision No.: 0
Date: 03/29/95
. Page A-3
may chtinge as a resulr of lhe.additional sampling. Wharever luzppens, there will be another
opponunity for public re~ew and comment on the cleanup .alternarives for Area 31.. The
Navy woul like 10 emphasize JhaI there is no cun-ent human health threat posed by the
contaminarion at Area 31. .
AREA 16-RUNW AY DITCHES
Off-site Properties
Comment 1: Why were the homes and farms on Frostad and Hoffman Roads, south of the
Area 16 runway ditches, not tested for chemical contamination?
Response 1: The remedial investigation focused o~ the jlightline and other areas at Ault .
Field that could have been contaminilted with industrial chemicals or waste products released
imo the ditch complex as a result of past practices by the Navy. Surface water flows from
thl! houses and farms. on Frostad and Hojfmmz Roads toward the ditch complex: Therefore.
. surface Waler and sediments from ~he ditches could not have conraminazed these properTies.
Chemical concentrati(Jns in the ditch sedimenrs decrease with distance from the jlightline. No
chemicals were detected at elevated concentrations in sedimem samples collected where the
ditches exit Navy property. The SedilUnt samples collected near the intersection of the
Hoffman Road ditches and the nmway ditches indicate thaI Hoffman Road is a source of
chemical contamination typical of urban runoff from car exhaust residues, oil, etc.
Laboratory results show that State Highway 20 is also a source of PAR contamination to the .
lagoon sedimenr. . .
Comment 2:. Do the homes and farms on Frostad and Hoffman Roads receive runoff from
Navy property? ..
Response 2: The homes and farms on Frostad and Hoffman Roads do not receive runoff
from Navy propeny. The Navy met with the homeo.wners and farm owners on MofuJay,
August 1, 1994, to walk along Whiskey Creek and follow the surface drainage features aJ
Hoffman and Frostad Roads. Whiskey Creek originates on the east side of Ho./fmm'z Roali,
east of the Navy propeny boundmy, and does not receive runoff from Navy property.
Surface water runoff from a small wetland exits Navy property and nms in the westernmost
.draiTUlge ditch along Hoffman Road, and then re-enters Navy property just sOUth of Frostad
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NAS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0074
, Final Record ,of Decision:
Revision No.: 0
Date: 03/29/95
Page A-4
Comment 3: Are the Hoffman Road ditches contaminated and is Hoffman Road included in
the cleanup actions?
Response 3: It is not known if the Hoffman Road ditches are contaminated and HojJman
Road is not included in the cleanup action. ,The remedial investigation was conducted on the
Navy base to examine the sources of contamination that are attriburable to the Navy. The
Hoffman Road ditches were not tested for contamination except where they meet the runway
ditches. Contaminant levels in samples collected where the urban runoff enters the runway
ditches are typical of road runoff and urban pollution. However, testin$ the Hoffman Road '
, ditches was neither required nor performed during the remedial investigation. Therefore,' no
statement as to whether the Hoffman Road ditches are contaminated can be supported by the
analytical tkua.
Comment 4: We live on the east and north sides of Area 16. How can we get our
p~perties tested?
Response 4: The Navy met with the homeowners and tested seven residential wells. The
NaVy attended a meeting on Monday, August 1, 1994; at the homeowners' resid~nces to
discuss the testing of their wells. The sampling and analysis was performed by the'
Washington State Depamnent of Heallh on September 14, 1994. The Department of Heallh
has discussed the test resulls, with all of the well users. The resulls showed no evidence of
vokztile organic compounds, herbicides, or pesticides. However, the'resulls indicated that
levels of naturally occurring inorganics (metals) are present in the water from all seven
wells. The specific metals detected Were iron, manganese, and arsenic. The Departmeni of
Health has stated that the levels of these metals are within the range found in other drinking
warer wells ithLzs tested in Iskznd County. One of the seven wells, however, had a detection
of aluminum that is not thought to be naturally occurring. This well is one of the farthest
from 'the NAS boundary. The propeny owner has been notified of this fact by the Depamnent
of Health. The resulls also indicated the presence of low levels of phthalates in water from
many of the wells. Phtha/ares are commonly as$ociated with plastics. The Department of .
" Health attribures the presence of phtha/ares to sample collection ,activities and laboratory
procedures, both of which invo.lve'plastic materials. '
Harrier Study
Comment 1: 'I am concerned with the potential impacts on the Northern Harrier posed by
the preferred remedial alternative~redging (Alternative 3). More data should be collected
to evaluate the relationship between the Nonhero Harrier. its prey (the vole), and the runway,
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~
N AS WlUDBEY ISLAND, OPERABLE UNIT 3 '
U.S. Navy - CLEAN Contract
EngineerlDg Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0074
Final RecOrd of Decision
Revision No.: 0
Date: 03/29/95
Page A-5 '
Response 1:. The Navy commissioned The InstitUle oj Wildlife and Environmemal Toxicology
(TlWET) at Clemson University to study the harrier-vole ime"elarionship on the nmway ,
. ditches in 1992. The results of this study showed a very healthy and vital harrier population'
at Ault Field and the Seaplane Base, most likely due to the large popularion oj voles on base.
If voles are driven our oj a small area like the 2,000 feet of nmway ditches to be dredged.
they will recolonize the disturbed area very quickly. . Voles are such voracious $T1Iflll
mammals, they will aCnuJlly nm other small species out. The voles breed extensively and
continuOusly in very early spring unrilthe late fall. and their. popularion declines to fairly
small numbers annually in late' sUfTl!1Zer. The harrier breeding season nms from early March
through June, and they are finished raising t!u!ir young by early August. The area to be
dredged is less than 0.01 percenr oj the total acreage available to the harrier and the vole.
If dredging occurs in late summer or early fall, there will be no significant impacts on the
harrier or vole populations. The Navy believes that based on this information, any remedial
, . action in the ditches will be protective of the harrier. .
The Navy is continuing its study of the harriers at NAS Whidbey Island. It is the Navy's
,polif:Y, to protect vaiUllble Nltural resources on Federallmzdand in support of ihis policy will . '
continue to srudy ihe vitality 'of the harrier population. This research 'will take several years
to complete and remedial action ps well as maimenance oj the ditch complex needs to be '
completed as soon as possible. '
Comment 2: During the TIWET study, did you fmd toxic substances'in the vole and harrier
eggs and their new fledglings?
Respo.nse 2: No chemical testing was performed on the eggs or the flesh of the fledglings as
pan of ihe TlWEI srudy. However, blood samples were collected from the young just bejort! '
. they fledged and analyzed fororganochloride pesticidis and metals. The levels wer~ similLu .
to those detected by other researchers on fledglings in the non hem foresrs 'of Canada. LetJd
and cadmium were also detecred, bur. not at levels rhat would prove harmful to this specie.
Comment 3: Do voles prefer colonizing in ditches?
Response 3: They may colonize the ditch banks because the dredged soil on the banks may
be softer than the s~o~ng areas and there is a close source of water.
Comment 4: Have you perfonned any studies on the harrier nests at the Seaplan~ Base aDd
how do they compare to nests at other sites?
, Response 4: The TlWET study investigated harriers at the Seaplane Base, AuJr Field, ami a
site sOUlhwest of Helkr Road. The results were fairly similar. The breeding success rata
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. .
NAS WHIDBEY ISLAND. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295 .
CTO 0074
Comment 5: Is 1 year enough time to establish a trend for the harriers?
" .
Final Record of Decision'
Revision No.: 0
Date: 03/29/95
Page A-6 .
. Response 5: No, it is not and actually tWo years is still insuffidenr time to establish a trend.
The Navy is continuing to research the' harrier population at NAS Whidbey Island. The Navy
is studying a few of the nesting sites and have fledgling counts for this year. The Navy also
has a member of Falcon Research doing bird banding and is planning to collect blood and
fecal samples for testing. .
. .
'. Comment 6: How did the nesting harriers this y~, compare with the findings of the 1992
TIWET study? .
Response 6: The current success rates for harriers, based on the number of nests and
number offledglings, are similar to the 1992 TIWET study results. The reporrfrom the 1992
11WET study indicated that the harrier populations have hatching success and nesting.
survival rates that are higher than normal. TJze harrier population at NAS Whidbey Island
haS lhe highest Iazown density of norrhern harriers breeding in western Washington.
Clover Vaney. Lagoon
. Comment 1:, ClovC?r Valley Lagoon should be cleaned up and restored to its fonner thriving
habitat for salmon, steelhead, and cutthroat. , . . '
Response 1: According 10 information oblained from interviews with members of the diu
commission and local farmers who have lived for more lhan 50years on Clover Valley
Lagoon, andfrom the Washinglon State fisheries, Clover Valley Lagoon was never a troUt or
salmon run. The hydrology and sediment characteristicspf the ditches and the lagoon.
preclude it from providing an adeqUate habitat for salmon and trout. The surface water does
: not run fast or cold enough for an effective fish hatchery nor are the ditch sediments coarse
eno'ugh (gravel or sand) for salmon to spawn. The state fishery depanment used 10 release
haIchery-raised fish on the ocean si~ of the dik£. One year there was'an accidental release
of the fish inco Clover Valley Lagoon and the ditch complex. The discovery of these fish,
which were fished OUI of the ditches, resulted in a newspaper article reporting fish in the
dirch complex. '
The chemicals detec;red in Clover Valley lAgoon surface. water and sediments are not Qthreal
to aquatic life. Within the upper 9 feel of the lagoon, there is a healthy ecosystem. Snails,
sticklebacks, frogs, and salamanders are prevalent. The shoreline of the iflgoon also
. provides nesting areas for many"species of birds. such as rhe mallard, teal, red-winged'
blackbird, and belred kingfisher. The ecosystem in the upper por-tion of the lagoon and along
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NAS WHIDBEY ISLAND, OPERABLE UNIT 3
U.S. Navy - CLEAN Contract.
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0074
Final Record of Dccision
Revision No.: 0
Date: 03/29/95
Page A-7
. The lack ofsimiiar living organisms below a depth of approximalely 9 feet is caused by an
oxygen-deficiem (arioxic) layer of seawaler underlying the freshwaler layer. Seawaler seeps.
Ihrough rhe dike and up from lhe bOllom of the li:zgoon. Because of the difference In densities
betWeen the lighter fresh Waler and the heavier sall warer and rhe low energy flow of the
freshwarer ditches imo the lagoon, no mixing oj the Walers occurs and hence an anoxic layer
is formed. . .
Comment 2: What about just making the lagoon shallow?
Response 2:. There is no reason to fill the lagoon Jor cleanup purposes. Filling the lagoon
. with sedimems would most likely cause consilkrable hann to the vibrant stickleback
popularion and would have ro be evaluated wirh other environmental impacrs that are beyond
. the scope of the remedial investigation/feasibility study. .
The Navy has requested monies from the Legacy program, which funds cultural and natural
resource projects. If funding is provided by this program, the feasibility oj upgrading rhe
dikl! system will be investigated.
Jet Fuel Residue
Co~en~ 1: [When at home] I can sll1ell JP-5 and have noticed residue on my car and
garden. Does the Nav.y test for jet fuel residue and what are the health effects from JP-5?
Response 1: There is a program althe base to testJor jetjuel residues allocations on and
off base. The Navy has peiformed residue testing as far t:lS La Cowr, Washington. There
is no" air testing for fuel residue or exhaust. If you feel you have afuel residue on "your car .
or windows, COnttlCt the Officer oj rheDay ar (206) 257-2631. Because fets bum juel most"
efficiently al 30,000 feet, not all of the fuel is burned ar lower elevarions. Panicularly on .
lake offi, there is often unburned fuel in the exhau.St. You may be able to detect the smell oj
jet fuel, or lP-5, in the exhaust.
A large shon-tenn exposure to a high concemrarion of jet fuel can irritare skin, eyes, and the
respiralory system and result in headache, dizziness, or nausea. "
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NAS WHIDBEYISLAND. OPERABLE UNIT 3
U.S. Navy - CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO,OO74
Final Record of Decision i .
Revision No.: 0
Date: 03/29/95
Page A-8' '
Ditch Dredging
Comment 1: po the concentrations of metals in the runway ditch sediments pose a risk to
human health or the environment? ' ,
Response 1: Metals concentrations detected in the ditch were evaluated in the human heallh
and ecological risk assessment. There was no unacceptable risk idenrified for humans from,
metal concentrarions in the ditch. There was, however, a potential risk identified for the
muskrat caused by ars.enic and lead in the runway ditch sediments. When cleanup actions
, begin, the amou.ncs of arsenic and lead will be reduced to levels that will nqt be a threaz to
the environment or to the muskrar. 7hi! highest levels of arsenic and lead detected in ditch
, sediments were 581 an4 942 pans per million, respectively.
As shown in Table 8-1 in the ROD, the remediarion goal for arsenic is 16 mg/kg (based on
the muskraz model) and the remediation goal for lead is 18 mg/kg (based on the backgroWld
concentration).
Comment 2: If the 'ditches were routinely dredged in the past," where, did the contMnination
that we are now seeing come from? ' ,
Response 2: .The ditcfzes have not been dredged for approximazely 14 years. .Therefore, the
comamination we, have observed is a result of past practices such as petroleum dumping in
the ditches thaz stopped around 1986. , .
Comment 3: When are you. going to deterIl\ine whether the sediments dredged from the
Area.l6 ditches are suitable for disposal under the Area 6 landfill cap?
Response 3: A sampling and analysis program in supporr of the remedial design will be
conducted in January/February 1995 to determine the proper disposal method.
Comment 4: Are you going to dig new ditches?
Response' 4: .The Navy is not planning to dig new ditches. .This alternative was evaluazed in
(he feasibiliry. ~tudy and the proposed plan.
CommentS:' Do you expect the ditches ever to become contaminated again. after ti:1ey are
dredged?
Response 5: No, the Navy does not expect the ditches to become conraminazed again. The'
Navy is instituting best management practices to reduce runoff from industrial areas into the
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NAS WHIDBEY ISLAND. OPERABLE UNIT 3
,U.S. Navy - CLEAN Contract .
Engineering Field Activity. Northwest
Contract No. N62474-89-D-9295
CTO 0074
Final Record Qf DecisioD
Revision No.: 0
Date: 03/29/95
Page A-9
of an accidemal fuel spill reaching the ditches. Fuel that reacheS the ditches would be
contained and pumped from the ditch at BajJle 1. Disposal of waste in the ditches no longer
occurs. Other efforts (recycling and waste' minimizarion) over the past 5 years have grearLy
reduced rhe amount of hazardous materials handled at the base. .
Comment 6: I~ there a monitoring device that could be in~talled to continUally fIlter and
recheck for contamination? . ,
.Response' 6: ,The Navy does have a program in pkzce that monitors the ditch effluent as pan
of its National Pollutant Discharge Elimination System (NPDES) permit. The hazardous
waste minimizarion program, rhe stormwater management program, and the spill response
piiln make the recontamination of the ditches unlikely. The Navy plDns to instdil stonnwarer
rreatmem at various locations, where needed. at NAS Whidbey Island: One location being
.consitkred is in the nmway ditches. . .
Co~ent 7: There really is no difference between maintenance dredging 3:Dd the preferred
a1temative~ If the Navy perfonns maintenance dredging instead of the preferred alternative,
. 'would . the excavation be deeper? '
Response 7: There is a difference berweenmaintenance dredging and lhe preferred
allernarive. . Specifically. the di.ffer~nces are in the method of disposing of the dredged
marenals and chemical mu;zLysis 01 rhe materials. The depths to which sedimenr would be
dredged for maimenance versus the preferred allernative are established using different
criteria. In rhe preferred allernarive, the comaminared sediment will be removed to the .
exrent necessary to meet remediation goals and the removed materials will be pkzced under
the' cap 01 the Area 6 landfill. In some' areas. thi! co,maminated sedimenr may be fl!lywhere .
. frOIn a few inches to. a few jeer deep.. As pan 01 maintenance dredgIng. sediments would be
dredged to create a sufficiem slope and an unclogged ditch allowing Water to flow freely and .
the dredged materials will be pl4ced on rhe. banks of the ditches. The depth of dredging for
maintenance purposes moy be from a few inches to a few feet.
Comment 8: Why is the Navy hiring a contractor to excavate the ditches-why not use the.
S~EDaS? . .
. Response 8: 11Ie Navy's Construction. Battalion (CB's) are commitied to otherrypes of
construction work and typically have not received the hazardous waste worker training
required by federal regulations for individuals who work on hazardous waste cleanup at
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l' AS Vo'HIDBEY ISLAND. OPERABLE UNIT 3
li .5, Savy . CLEAN Contract
EqiDeering Field Activity, Northwest
Coatnct No. N62474-89-D-9295
CTO 0074
Final Record of Decision:
Revision No.: 0
Date: 03/29/95
Page A-lO
Comment 9: Who is choosing the contractors for the remedial actions and is the creation of
jobs in the community being given any consideration?
Response 9: The Navy has competitively selected a conrr~tor to conduct cleanup actions at
No\')" bases in the Puget Sound area. In order to accomplish this contract award, the Navy
followed 0 federally mandated procuremenr process which is intended to maximize
competition by giving finns afair chance at winning the contract. This includes giving small
and disadvantaged businesses an opportuniry to receive work through subconrracts. The
cleanup contractor can and does utilize local subcontractors to help perfonn the work. The'
No\'y has also recenrly used a local contractor for the OU 1 water hookups. '
Evaluation of Alternatives'
Comment 1: Alternatives 2 and 3 have sigirificant differences only in cost. Since either
Alternative 2 or Alternative 3 would ensure maintenance of the ditches to prevent flooding, it
seems imprudent to select the most expensive solution. '
Response 1: The higher cost for Alternative' 3 is on account of a contingency if the nwrerials
dredged from the ditches cannot be disposed of in the Area 6 landfill. Alternatives 2 and 3
, include different rypes of action, which contribUtes to the difference in cost. Alternative 2
includes the constrUction of new ditches to bypass the current areas of contamination. SQil,
removed for cons.rruction of the new ditches would be used to cOVer the existing ditches, thus.
leaVing contamination in place. Alternative 3 involves characterization of the contaminated
sediments and then dredging of these sediments with ultimate disposal of the removed
materials under the cap of the landfill at Area 6. Under this des.cribed alternative, all '
contaminated sedimenr,s are removed from the ditch nerwork. .
Alternative 2 would disturb more of the habitat around the ditch complex than Alternative 3.
Alternative 2 involves excavating a new ditch (10 feer wide by 15 feer by 3,000 feerlongj and
filling in the. old ditch,. which is approximately the same dimensions. Compared to
Alternative 3, Alternative 2 would disturb twice the area and volume. Alternative 3 will
remove the sediments only on the bottom of the ditch (5 feet wide by 2 feet deep by 3.000 feet
long). The bOllom sediments are not 0 habitat for the voles. The vole habitat toot would be
disturbed by Alternative 3 is the area adjacent to the ditch banks and this disruption would
be limited to that caused .by' a traclanounred backhoe and dump trucks. The costs for
Alternative 2 and Alternative 3 are estimated to be comparable at the low end ($0.6 million).
All costs associated with these alternatives are approximate and are considered to be
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NAS WIDDBEY ISLAND. OPERABLE.UNIT 3
U.S. Navy - CLEAN Contract .
. Engineering Field Activity. Northwest
Contract No. N62474-89-D-929S
CTO 0074
Final Record of Decision.
Revision No.: 0
Date: 03/29/95
. Page A-ll
. Comment 2: Sediments from specific segments of the runway ditches where co~taminated
sediments have ~n' found should be removed and disposed of. . This should include
sampling the ditch sediments near particular sampling stations that showed evidence of
contaniination during the remedial'investigation, excavating or dredging the sediments from
. the areas upstream and downstream of these locations, and managing the removed material.
If contaminant concen~tions ii1 the dredged material are below the'state standards for.
classification as hazardous materials, the material CQuid be placed in the Area 6 landfill and
covered. TI1is should, of course, incl~de the runway ditches outside the main flightline area, .
as well as within the flightline area. . , , .
Once the ditches have been cleaned of contaminated sediments, they should be filled and
capped.. New runway ditches should be excavated and lined with a nonporous material and a
drainage pipe'should be laid within the ditches and covered. A treatmentidecontaIriination
station should be placed at Baffle 1.
Response 2: The suggestion to remove conramiTllJle4 sedimenrs and properly dispose oj them,
, in the Area 6 IJJ1Idfill is the preferred alternmive, Alternative 3: ,The one exceptif!n to ~his. '
approach is the sediments in the area of the heron rookery. Dredging these sediments would
damage the trees and habitat in the area. Installing a piped stormwater system in the
drainage ditch complex would not be the best management practice for the stormwater
processes at NAS Whidbej Islllnd. In the Fallof 1994, EPA inspected the ditches and stated
that the existing design of the ditches is adeqUate. No inspection report has been received.
An open-jlowing chtmnel with vegelazion is considered one of the best natural pollution
control systems, especially for the rype of contamination that could accitkntally spill into the
dirch system from a fuel release. The open ditch will allow for rapid and easy spill
containment and cleanup by providing direct access to the eMre spill. The spill can bt!
' 'conrained by Baffle] or oil booms and can be removed using vacuum trucks and oil
'absorbent nuiterials. '
The open ditch system will also provitk a habitat for various animal species. The reason for
taking any environmental action at Area 16 is the ecological risk to the muskrat. Encasing
rhe ditch in concrete would eliminate the habitat/or these animals'and, therefore, pose more
environmental risk for the muskrai and other animals. The costs of installing an enclosed
system is very prohibitive and would not ensure that contamination would not migrate into
the' subsurface or directly inro Clover VaUey Lagoon. ' , ,
The Navy is installing storm water treatment units at the base and possibly in the runway
ditch complex. These systems will be installed as pan of the continuing efforts by NAS
Whidbey Island to upgrade its pollution prevention program. ' The units are expected to be
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