PB96-964610
EPA/ROD/R10-96/142
August 1996
EPA Superfund
Record of Decision:
Naval Air Station. Whidbey Island - Ault Field,
Operable Unit 5, Areas 1, 52, and 31,
Oak Harbor, WA
7/10//1996
-------
-------
FINAL
RECORD OF DECISION
OPERABLE UNIT 5
NAVAL AIR STATION
WHIDBEY ISLAND
OAK HARBOR, WASHINGTON
Prepared by
U"RS Consultants, Inc.
Seattle, Washington
Prepared for
Engineering Field Activity, Northwest
Southwest Division, Naval Facilities Engineering Command
Poulsbo, Washington
May 1996
-------
-------
DECLARATION OF THE RECORD OF DECISION
SITE NAME AND ADDRESS
Naval Air Station Whidbey Island, Ault Field
Operable Unit 5, Areas 1, 52, and 31
Oak Harbor, Washington
STATEMENT OF PURPOSE
This decision document presents the final remedial action for Operable Unit (OU) 5, one of four operable
units at the Naval Air Station (NAS) Whidbey Island, Ault Field, Superfund site near Oak Harbor,
Washington. The selected remedy in this decision document was chosen in accordance with 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 (NCP). This decision is based on the
Administrative Record for OU 5.
The U.S. Navy (Navy) is the lead agency for this decision. The U.S. Environmental Protection Agency
(EPA) has approved of this decision. The State of Washington concurs with the selected remedy.
t-
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from OU 5, 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 SELECTED REMEDIES
OU 5 originally consisted of Area 1 (the Beach Landfill) and Area 52 (the Jet Engine Test Cell). Area 31
(the Former Runway Fire School) was studied as part of OU 3. Because of the need for further equation
and to avoid delaying cleanup of the other site at OU 3, Area 31 was moved from OU 3 and incorporated
into OU 5.
There are no human health risks associated with Area 1. The selected remedy at Area 1 addresses potential
ecological risks. Groundwater at Area 1, although not a potential source of drinking water, discharges to
marine water. The groundwater was found to contain cyanide at concentrations that could adversely affect
marine life. However, biological surveys of the beach and intertidal zone found no apparent ill effects to
biota from Area 1. The selected remedy includes sampling in the intertidal zone and groundwater
monitoring, along with biological surveys of the beach, to determine if ecological risks exist and if further
actions are needed to protect marine Me. The selected remedy also includes use restrictions to prevent
installation of drinking water wells or development that could cause human or environmental exposure to
landfill contents.
There are no human health risks associated with Area 52. The selected remedy at Area 52 addresses
potential ecological risks posed by floating petroleum product on the groundwater. Groundwater at Area 52,
although not a potential source of drinking water, discharges to marine water. The objective at Area 52 is to
prevent the petroleum from discharging to marine water, but not to clean up groundwater to drinking water
standards. The petroleum will be skimmed from the groundwater and treated or recycled off site.
Groundwater monitoring will be conducted to evaluate the effectiveness of the remedy. The selected remedy
31620\9605.040\ID
-------
also includes use restrictions to prevent installation of drinking water wells and to limit development that
could expose humans to petroleum.
The selected remedy at Area 31 addresses exceedances of drinking water standards and potential future
human health risks posed by chemicals found in groundwater. The sources of these chemicals are an
oil/water separator and associated petroleum-contaminated soils and floating petroleum product on the
groundwater. The objective at Area 31 is to remove enough of these sources so that groundwater
contamination does not spread, but not actively clean up groundwater to drinking water standards. The
oil/water separator will be excavated and disposed of, and the petroleum will be skimmed from the
groundwater and treated or recycled off site. The selected remedy includes oil skimming and bioventing;
bioventing is intended as a contingent measure. Groundwater monitoring will be conducted. The selected
remedy also includes use restrictions to limit development and prevent installation of drinking water wells.
The selected remedies for both Areas 31 and 52 rely on natural attenuation to achieve groundwater cleanup
levels over the long term.
STATUTORY DETERMINATIONS
The selected remedies are protective of human health and the environment, are in compliance with federal
and state requirements that are legally applicable or relevant and appropriate to the remedial action, and are
cost-effective. The remedies utilize permanent solutions and alternative treatment (or resource recovery)
technologies to the maximum extent practicable.
For Areas 31 and 52, the remedies satisfy ithe statutory preference for treatment that reduces toxicity,
mobility, or volume as a principal element. However, for Area 1, because treatment of the principal threats
from the site was not found to be practicable, the remedy does not satisfy the statutory preference for
treatment. At each site, the remedies will result in hazardous substances, pollutants, or contaminants
remaining on site. Therefore, each remedial action will be reviewed no less than every 5 years to ensure that
human health and the environment are being protected.
31620X9605.040\ID
-------
Signature sheet for the foregoing Naval Air Station Whidbey Island, Ault Field, Operable Unit 5, final
remedial action, Record of Decision, between the U.S. Navy and the U.S. Environmental Protection Agency,
with concurrence by the Washington State Department of Ecology.
Chuck Clarke Date
Regional Administrator, Region 10
U.S. Environmental Protection Agency
31620\9605.040\ED
-------
Signature sheet for the foregoing Naval Air Station Whidbey Island, Ault Field, Operable Unit 5, final
remedial action, Record of Decision, between the U.S. Navy and the U.S. Environmental Protection Agency,
with concurrence by the Washington State Department of Ecology.
aptain LJ. Munns
Commanding Officer, Naval Air Station Whidbey Island
U.S. Navy
Date
31620\9605.040\ID
-------
Signature sheet for the foregoing Naval Air Station Whidbey Island, Ault Field, Operable Unit 5, final
remedial action, Record of Decision, between the U.S. Navy and the U.S. Environmental Protection Agency,
with concurrence by the Washington State Department of Ecology.
Program Manager, Toxics Cleanup Program
Washington State Department of Ecology
31620\9605.040\ID
-------
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page xi
CTO 0162
CONTENTS
Section Page
ABBREVIATIONS AND ACRONYMS xvii
1.0 INTRODUCTION 1
2.0 SITE NAME, LOCATION, AND DESCRIPTION 1
2.1 AREA 1—BEACH LANDFILL 3
2.2 AREA 52—JET ENGINE TEST CELL 3
2.3 AREA 31-FORMER RUNWAY FIRE SCHOOL 6
3.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES 8
3.1 SITE HISTORY 8
3.2 PREVIOUS INVESTIGATIONS AT NAS WHIDBEY ISLAND 9
4.0 COMMUNITY RELATIONS 10
5.0 SCOPE AND ROLE OF OPERABLE UNITS 13
6.0 SUMMARY OF SITE CHARACTERISTICS 13
6.1 PHYSICAL CHARACTERISTICS 14
6.1.1 Area 1 14
6.1.2 Area 52 16
6.1.3 Area 31 19
6.1.4 Groundwater Potability 25
6.2 NATURE AND EXTENT OF CONTAMINATION 26
6.2.1 Area 1 27
6.2.2 Area 52 33
6.2.3 Area 31 38
7.0 SUMMARY OF SITE RISKS 47
7.1 HUMAN HEALTH RISK ASSESSMENT 47
7.1.1 Chemical Screening 48
7.1.2 Exposure Assessment 49
7.1.3 Toxicity Assessment 58
31620\9605.WO\TOC
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page xii
CTO 0162
CONTENTS (Continued)
Section Page
7.1.4 Risk Characterization 59
7.1.5 Results 61
7.1.6 Uncertainty 63
7.2 ECOLOGICAL RISK ASSESSMENT 66
7.2.1 Area 1 66
7.2.2 Area 52 77
7.2.3 Area 31 78
7.2.4 Ecological Risk Assessment Summary 82
7.3 SUMMARY OF SITE RISKS 83
8.0 REMEDIAL ACTION OBJECTIVES 83
8.1 AREA 1 ........» 83
8.1.1 Need for Remedial Action 83
8.1.2 Remedial Goals 86
8.2 AREA 52 86
8.2.1 Need for Remedial Action 86
8.2.2 Remedial Goals 88
8.3 AREA 31 89
8.3.1 Need for Remedial Action 89
8.3.2 Remedial Goals 92
9.0 DESCRIPTION OF ALTERNATIVES 94
9.1 AREA 1 94
9.1.1 Alternative 1—No Action 94
9.1.2 Alternative 2—Limited Action—Institutional Controls and
Monitoring 94
9.1.3 Alternative 3—MFS Cap and Installation of Seawall . 96
9.2 AREA 52 98
9.2.1 Alternative 1—No Action 98
9.2.2 Alternative 2—Oil Skimming 98
9.3 AREA 31 101
9.3.1 Alternative 1—No Action 101
9.3.2 Alternative 2—Oil Skimming 101
9.3.3 Alternative 3—Oil Skimming and Bioventing 103
9.3.4 Alternative 4—Soil Excavation and Removal 105
31620\9605.040,TOC
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page xiii
CTO 0162
CONTENTS (Continued)
Section Page
10.0 COMPARATIVE ANALYSIS OF ALTERNATIVES 107
10.1 AREA 1 . . 107
10.1.1 Overall Protection of Human Health and the Environment ... 108
10.1.2 Compliance With Applicable or Relevant and Appropriate
Requirements 108
10.1.3 Long-Term Effectiveness and Permanence 109
10.1.4 Reduction of Toxicity, Mobility, or Volume Through
Treatment 109
10.1.5 Short-Term Effectiveness 109
10.1.6 Implementability 109
10.1.7 Cost ..... 109
10.1.8 State Acceptance 110
10.1.9 Community Acceptance 110
10.2 AREA 52 110
10.2.1 Overall Protection of Human Health and the Environment ... 110
10.2.2 Compliance With Applicable or Relevant and Appropriate
Requirements Ill
10.2.3 Long-Term Effectiveness and Permanence Ill
10.2.4 Reduction of Toxicity, Mobility, or Volume Through
Treatment Ill
10.2.5 Short-Term Effectiveness . . . . . 112
10.2.6 Implementability 112
10.2.7 Cost . ." 112
10.2.8 State Acceptance 112
10.2.9 Community Acceptance 112
10.3 AREA 31 113
10.3.1 Overall Protection of Human Health and the Environment ... 113
10.3.2 Compliance With Applicable or Relevant and Appropriate
Requirements 113
10.3.3 Long-Term Effectiveness and Permanence 114
10.3.4 Reduction of Toxicity, Mobility, or Volume Through
Treatment 114
10.3.5 Short-Term Effectiveness 114
10.3.6 Implementability 115
103.7 Cost 115
31620\9605.O40\TOC
-------
NAS WfflDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page xiv
CTO 0162
CONTENTS (Continued)
Section Page
10.3.8 State Acceptance 115
10.3.9 Community Acceptance 115
11.0 THE SELECTED REMEDY 116
11.1 AREA 1 116
11.2 AREA 52 117
11.3 AREA 31 119
12.0 STATUTORY DETERMINATIONS 122
12.1 AREA 1 . 122
12.1.1 Protection of Human Health and the Environment 122
12.1.2 Compliance With ARARs 122
12.1.3 Cost Effectiveness 124
12.1.4 Utilization of Permanent Solutions and Treatment
Technologies to the Maximum Extent Practicable 124
12.1.5 Preference for Treatment as a Principal Element 124
12.2 AREA 52 125
12.2.1 Protection of Human Health and the Environment 125
12.2.2 Compliance With ARARs , . 125
12.2.3 Cost Effectiveness 126
12.2.4 Utilization of Permanent Solutions and Treatment
Technologies to the Maximum Extent Practicable 127
12.2.5 Preference for Treatment as a Principal Element 127
12.3 AREA 31 127
12.3.1 Protection of Human Health and the Environment 127
12.3.2 Compliance With ARARs 128
12.3.3 Cost Effectiveness . 129
12.3.4 Utilization of Permanent Solutions and Treatment
Technologies to the Maximum Extent Practicable 129
12.3.5 Preference for Treatment as a Principal Element 130
13.0 DOCUMENTATION OF SIGNIFICANT CHANGES 130
31620\9605.040\TOC
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page xv
CTO 0162
CONTENTS (Continued)
APPENDIX
A Responsiveness Summary
FIGURES Page
1 NAS Whidbey Island Location Map 2
2 Area 1, Operable Unit 5, Beach Landfill . 4
3 Area 52, Operable Unit 5, Jet Engine Test Cell 5
4 Area 31, Operable Unit S^Former Runway Fire School 7
5 Generalized Hydrogeologic Conditions—Areas 1 and 52 17
6 Surface Water Flow Directions—Area 31 and Adjacent Property 20
7 Location of Cross Sections—Area 31 22
8 Geologic Cross Section C-C'—Area 31 23
9 Geologic Cross Section D-D'—Area 31 24
10 Area 1 Sampling Locations 29
11 Area 52 Sampling Locations 34
12 Area 52—Apparent Thickness of Floating Petroleum Product Measured in
Monitoring Wells, January 23, 1995, and May 18, 1990 36
13 Area 31 Sampling Locations 39
14 COCs in Area 31 Groundwater—Shallow Unconfined Aquifer 45
TABLES
1 Screening Criteria Used at OU 5 28
2 Chemicals of Concern at Area 1 30
3 Chemicals of Concern at Area 52 33
4 Chemicals of Concern at Area 31 (Phase I and Phase II—Included in Risk
Assessment) 40
5 Chemicals of Concern at Area 31 (Phase III—Post Risk Assessment) 42
6 Human Exposure Models Selected to Evaluate Potential Risks From
Chemicals at OU 5 50
7 Exposure Parameters Used in Human Health Risk Assessment at OU 5 .... 52
31620\9605.040\TOC
-------
HAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page xvi
CTO 0162
TABLES (Continued)
No. Page
8 Summary of Potential Human Health Risks and COCs at Area 31 62
9 Maximum Detected Groundwater Concentrations (Area 31) Compared
With Default Groundwater RBSCs for Chemicals Not Included in 1992
Baseline HHRA . . 63
10 , Ecological Risk-Based Screening Summary at Area 1 71
11 Summary of Hazard Quotients to Terrestrial Receptors at Area 31 81
12 Chemical-Specific ARARs for Area 1 Groundwater 87
13 Chemical-Specific ARARs for Area 52 Groundwater 89
14 Chemical-Specific ARARs for Area 31 Groundwater 93
31620\9605.040\TOC
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0162
Final Record of Decision
Revision No.: 0
Date: 05/21/96
Page xvii
ABBREVIATIONS AND ACRONYMS
ACF
ARAR
avgas
AWQC
BAF
BJP
BTEX
bgs
CERCLA
CFR
COC
COPC
cPAH
CR
CSF
CWA
DC
ODD
DDE
DoD
DDT
Ecology
EFANW
EPA
EqP
ER-L
FED MCL
FFA
HEAST
HHRA
HI
HQ
water to air conversion factor
applicable or relevant and appropriate requirement
aviation gasoline
ambient water quality criteria
bioaccumulation factor
best professional judgment
benzene, toluene, ethylbenzene, and xylenes
below ground surface
Comprehensive Environmental Response, Compensation,
and Inability Act of 1980
Code of Federal Regulations
chemical of concern
chemical of potential concern
carcinogenic polycyclic aromatic hydrocarbon
cancer risk
cancer slope factor
Clean Water Act
dermal contact
dichlorodiphenyldichloroethane
dichlorodiphenyldichloroethene
U.S. Department of Defense
Dichlorodiphenyltrichloroethane
Washington State Department of Ecology
Engineering Field Activity, Northwest
U. S. Environmental Protection Agency
equilibrium partitioning
effects range-low
Federal Safe Drinking Water Act, Maximum Contaminant
Levels
federal facility agreement
EPA's Health Effects Assessment Summary Tables
human health risk assessment
hazard index
hazard quotient
31620\9605.040\TOC
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0162
Final Record of Decision
Revision No.: 0
Date: 05/21/96
Page xviii
ABBREVIATIONS AND ACRONYMS (Continued)
ING
INH
IR
IRIS
JP-5
LOEL
MCL
MCLG
MFS
msl
MTCA
MW
NA
NACIP
NAS
NAVFACENGCOM
NAVY
NC
NCP
ND
NE
NPL
O&M
OU
OWS
PAH
PCB
RAB
RAO
RBSC
RCW
RfD
RI/FS
RME
ROD
SARA
ingestion
inhalation
Installation Restoration
EPA's Integrated Risk Information System
jet petroleum fuel #5 .
lowest-observed effects level
maximum contaminant level
maximum contaminant level goals
Minimum Functional Standards
mean sea level
Model Toxics Control Act
monitoring well
not applicable
Navy 'Assessment and Control of Installation Pollutants
Naval Air Station
Naval Facilities Engineering Command
U.S. Navy
not calculated
National Oil and Hazardous Substances Pollution
Contingency Plan
not detected
not evaluated
National Priorities List
operating and maintenance
operable unit
oil/water separator
polycyclic aromatic hydrocarbon
poly chlorinated biphenyl
Restoration Advisory Board
remedial action objective
risk-based screening concentration
Revised Codes of Washington
reference dose
remedial investigation/feasibility study
reasonable maximum exposure
record of decision
Superfund Amendments and Reauthorization Act of 1986
31620\9605.WO\TOC
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0162
Final Record of Decision
Revision No.: 0
Date: 05/21/96
Page xix
ABBREVIATIONS AND ACRONYMS (Continued)
SQS sediment quality standards
SVOC semivolatile organic compound
TAL target analyte list
TBC to be considered
TCDD tetrachlorodibenzo-p-dioxin
TCL target compound list
TCLP toxicity characteristics leaching procedure
TEC toxicity equivalency concentration
TPH total petroleum hydrocarbons
TRC Technical Review Committee
TRV toxicity reference value
UCL upper confidence limit
USC United States Code
UST underground storage tank
VOC volatile organic compounds
WAC Washington Administrative Code
WA FWQS Washington Water Pollution Control Act, Fresh Water
Quality Standards
WA MCL Washington State Maximum Contaminant Levels
WA MWQS Washington Water Pollution Control Act, Marine Water
Quality Standards
95UCL 95 percent upper confidence limit
31620V9605.040TOC
-------
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 1
CTO 0162
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 Super-fund
Amendments and Reauthorization Act of 1986 (SARA), and, to the extent practicable,
the National Oil and Hazardous Substances Pollution Contingency Plan (NCP), the U.S.
Navy (Navy) is addressing environmental contamination at Naval Air Station (NAS)
Whidbey Island, Ault Field, by undertaking remedial action. The selected remedial
actions have the approval of the U.S. Environmental Protection Agency (EPA) and the
concurrence of the Washington State Department of Ecology (Ecology) and are
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, the 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 1). The island is oriented north-south, with a length of almost
40 miles and a width varying from 1 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): 1, 2, 3, and 5. The Seaplane Base was a separately listed Superfund site and
constituted OU 4. The Seaplane Base was delisted in 1995.
This Record of Decision (ROD) addresses OU 5, which consists of Area 1, the Beach
Landfill; Area 52, the Jet Engine. Test Cell; and Area 31, the Former Runway Fire
School. Area 31 was originally included as part of OU 3. Because further study and
evaluation were needed at Area 31, and to avoid delaying cleanup at the other OU 3
area, Area 31 was transferred to OU 5.
31620\9605.(WO\TEXT
-------
NASWhidbey Island
Ault Field
_J NASWhidbey Island
Seaplane Base
NASWHIDBEY ISLAND I
WASHINGTON
Operable
STRAIT OF
JUANDEFUCA
AULT FIELD
I
—I
J CITY OF
OAK HARBOR /
cci
P!
0 1
Scale in Miles
WHIDBEY ISLAND
SEAPLANE BASE
.' OAK
, HARBOR
CRESCENT
HARBOR
CLEAN
COMPREHENSIVE
LONG-TERM ENVIRONMENTAL
ACTION NAVY
Figure 1
NAS Whidbey Island
Location Map
CT00162
Operable Unit 5
NAS Whidbey Island, WA
ROD
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 3
CTO 0162
2.1 AREA 1-BEACH LANDFILL
Area 1, a 6-acre landfill running parallel to the Strait of Juan de Fuca, is located west of
the intersection of Saratoga and Princeton Streets, between the Norwester Club and the
Jet Engine Test Cell (Figure 2). The site originally consisted of low-lying beach ridges
with several salt marshes seaward of the historical bluff located west of Saratoga Street.
The area is now at an elevation similar to that of the former bluffs and has been
completely filled in by naval construction activities. Two small marsh areas remain: the
central marsh located in the middle of the landfill, which serves as a retention pond for a
storm drain from Saratoga Street, and the southern marsh located at the southwestern
end of the landfill, which appears to remain at its original pre-landfill elevation.
Area 1 was used for disposal of demolition and construction debris from the construction
of the base between the 1940s and the 1970s. Some of the station's waste was released
and burned at the landfill from 1945 to 1958. Because the waste was burned, products of
incomplete combustion may exist in the fill. Erosion along the beachfront has exposed
the fill in many areas. Timbers, refuse, metal, and concrete are present in the exposed
shoreline bluff.
The beach and intertidal environment at Area 1 is a high-energy environment, which
does not provide particularly good habitat for most species of marine life. Shellfish are
not present in the intertidal zone because it is a high-energy environment. The
approximately 10-foot-high shoreline bluff is above the high tide line.
Area 1 has not been identified as a sensitive area for historic or archeological resources;
it is not in a flood plain and is not considered a critical habitat for endangered species.
However, bald eagles, listed as a threatened species, have been observed at Area 1,
22 AREA 52—JET ENGINE TEST CELL
Area 52, the Jet Engine Test Cell, is an active facility where jet engines are tested. It is
located southwest of the intersection of Saratoga Street and Enterprise Road (Figure 3).
Area 52, like Area 1, has been elevated to its current topography by emplacement of fill
materials into a low marsh area. East of Saratoga Street are two 10,000-gallon
underground jet fuel storage tanks with aboveground ancillary equipment enclosed by a
chainlink fence. An underground fuel supply line runs from these tanks to the test
facilities. Several buried utilities, a large storm drain, and other underground pipelines
31620\9605.040\TEXT
-------
Drainage Ditch
r
/ Paved
\
^
Suspected Bum Area
Storm Drain Outfall
strait of Juan de Fuca
Storm Drain Line
Suspected Burn Area
..„..,- Land Surface Elevation Contour
Approximate Landfill Boundary
Figure 2
Area 1, Operable Unit 5
Beach Landfill
CT00162
Operable Unit 5
MAS Whidbey Island, WA
ROD
COMPREHENSIVE
LONG-TERM ENVIRONMEf
ACTION NAVY
533162004-2-040496
-------
Approximate Jet Fuel
Location
Approximate Fuel
Line Leak Location
Underground
Storage Tanks
oc
O
100 200
•
Scale in Feet
LEGEND
Approximate Location of Release
CLEAN !
COMPREHENSIVE |
LONG-TERM ENVIRONMENTAL |
ACTION NAVY i
i
Figure 3
Area 52, Operable Unit 5
Jet Engine Test Cell
CT00162
Operable Unit 5
NAS Whidbey island. WA
ROD
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 6
CTO 0162
exist in the site vicinity. Product releases associated with Area 52 include jet fuel and
other waste constituents described below.
The release of jet fuel from the test cell facilities has been documented in two locations
(Figure 3). First, two major fuel spills took place when the underground storage tanks
(USTs)on the east side of Saratoga Street were being filled. The spills reportedly
occurred in 1986 and 1987, and it is estimated that about 1,200 gallons were released
from each spill. An Unqualified portion of the product was recovered. Leak testing of
the USTs indicated no leakage from the tanks themselves. Second, a leak was
discovered in the underground piping that leads from the storage tanks to the test cell.
This leak was located, excavated, and repaired at a coupling near the southwest corner of
the test cell. The duration and volume of this leak are unknown. The leaks were
repaired in the early 1990s and soils from the excavation were stockpiled on site. The
soils were later sampled and disposed of properly.
i
Disposal of waste oil and solvents may have occurred at two locations in Area 52
(Figure 3): a 6-inch-diameter open-bottom steel-cased dry well and a sunken depression
near an existing storm drain (in the vicinity of MW-4, exact location unknown). These
features are located southwest of Building 2610 and northwest of the parking lot,
respectively. The disposed wastes reportedly included hydraulic oil, solvents, and other
hydrocarbon wastes. The duration of these disposal practices and the total volumes
discharged are unknown.
Another potential source of non-jet fuel waste constituents is an inactive concrete sump
located near the northwest corner of Building 2610. Little is known of the waste disposal
practices at this location.
2.3 AREA 31—FORMER RUNWAY FIRE SCHOOL
Area 31 is located approximately 400 yards northeast of the intersection of Runways
13-31 and 7-25 (Figure 4); Area 31 was used for firefighting training from 1967 to 1982.
Waste fuels such as aviation gasoline (avgas) and jet petroleum #5 (JP-5), waste oil,
solvents, thinners, and other flammable material were ignited and extinguished in a
shallow concrete burn pad. The entire drill area consists of 1 to 2 acres, sloping gently
southwest. The burn pad, roughly 50 by 50 feet, consists of a retaining lip around its
perimeter and a floor that slopes toward a drain in the center. A mixture of flammable
liquids used for firefighting training was stored in an UST in the southeast corner of the
31620\9605.CWO\TEXT
-------
Boundary of Navy \
Firefighting \\\
Training Area
& Ash Pile or Areas of Ash
Approx. Location of Buried Piping
Shallow Ditch
» ~ * *» Fence Line
Elevation Contour Lines (ft above msl)
CLEAN
COMPREHENSIVE
LONG-TERM ENVIRONMENTAL
ACTION NAVY
Figure 4
Area 31, Operable Unit 5
Former Runway Fire School
CT00162
Operable Unit 5
MAS Whidbey Island, WA
ROD
533162004-na-040495
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 • Page 8
CTO 0162
drill area (175 feet from the burn pad). Oily water from the burn pad was drained
through an oil/water separator in the southwest corner of the drill area (200 feet from
the burn pad).
Previous firefighting training consisted of igniting flammable material in the pit and
extinguishing the fire. In the process of extinguishing the fire, flammable materials may
have been forced from the pad onto the surrounding ground.
Unburned liquids were drained from the center of the pad through underground piping
to the oil/water separator. After water was separated from floating product, it was
discharged to a small ditch that led to a depression in the southwest portion of Area 31
and drained to the runway ditches. Remains of some of the material burned in the pad
included ash and metal debris. This material was removed from the pad and piled in
various areas on or near the perimeter of the drill area. The ash piles consist of fused
metal debris that is broken into chtmks, with a small amount of dust-sized particles.
Landing gear components are present in the ash piles. Sources of potential chemical
releases include activities at the burn pad, the UST, and the oil/water separator, as well
as the ash deposited over the area from burning at the pad and the ash piles.
3.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES
3.1 SITE HISTORY
NAS Whidbey Island was commissioned on September 21, 1942. The station was placed
on reduced operating status at the end of the war. In December 1949, the Navy began a
continuing program to increase the capabilities of the air station. The station's current
mission is to maintain and operate Navy aircraft and aviation facilities and to provide
associated support activities. Since the 1940s, operations at NAS Whidbey Island have
generated a variety of hazardous wastes. Prior to the establishment of regulatory
requirements, these wastes were disposed of using practices that were considered
acceptable at that time.
In response to the requirements of CERCLA, the U.S. Department of Defense (DoD)
established the Installation Restoration (IR) Program. The Navy, in turn, established a
Navy IR program to meet the requirements of CERCLA and the DoD IR Program.
From 1980 until early 1987, this program was called the Navy Assessment and Control of
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 9
CTO 0162
Installation Pollutants (NACIP) program. Under the NACIP program, a set of
procedures and terminologies were developed that were different from those used by the
EPA in administrating CERCLA- As a result of the implementation of SARA, the Navy
has dropped NACIP and adopted the EPA CERCLA/SARA procedures and
terminology. Responsibility for the implementation and administration of the IR
program has been assigned to the Naval Facilities Engineering Command
(NAVFACENGCOM). The Southwest Division of NAVFACENGCOM has
responsibility for the western states. Engineering Field Activity, Northwest (EFA NW)
has responsibility for investigations at NAS Whidbey Island and other naval installations
in the Pacific Northwest 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. A more focused follow-up investigation and report, the NAS
Whidbey Island current situation report, was completed in January 1988. After the
current situation report was completed, further investigations were proposed for areas
where contamination was verified and where unverified conditions indicated further
investigations were appropriate.
While the current situation report was being prepared, EPA Region 10 performed
preliminary assessments at NAS Whidbey Island, Ault Field, to evaluate risks to public
health and the environment using the Hazard Ranking System.
In late 1985, the EPA 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. The EPA's inclusion of Ault Field on the NPL was based on the number of waste
disposal and spill sites discovered, the types and quantities of hazardous constituents
(such as, petroleum products, solvents, paints, thinners, jet fuel, pesticides, and other
wastes), and the potential for domestic wells and local shellfish beds to be affected by
wastes originating from the site.
As a result of the NPL listing, the Navy, the EPA, and Ecology entered into a federal
facility agreement (FFA) in October 1990. The FFA established a procedural framework
and schedule for developing, implementing, and monitoring appropriate response actions
at NAS Whidbev Island.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 10
CTO 0162
Following CERCLA and SARA guidelines, various sites and areas at NAS Whidbey
Island were later grouped into "operable units." The term "operable unit" is used to
designate specific areas undergoing a remedial investigation/feasibility study (RI/FS).
Two areas at Ault Field (Area 1 and Area 52) were collectively identified as OU 5. . An
RI/FS for OU 5 was conducted in 1994 to 1995, with the final RI/FS report issued in
June 1995. 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.
Two other areas at Ault Field (Area 16 and Area 31) were originally identified as OU 3.
An RI/FS for OU 3 was conducted in 1992, with the final RI report issued in January
1994 and the final feasibility study report issued in April 1994. A proposed plan
presenting the Navy's preference for remedial action was published for public comment
in July 1994. Public comments on the OU 3 proposed plan included questions regarding
whether the cost of the preferred alternative at Area 31 was appropriate when compared
with the current and potential future risks. Because of these comments, the Navy
decided to conduct further study and investigate additional remedial action alternatives
for Area 31. To avoid delaying cleanup at Area 16, Area 31 was transferred from OU 3
toOUS.
A final revised feasibility study report for Area 31 was issued in September 1995. This
revised report incorporated additional data collected during two field investigations at
Area 31 and evaluated two additional remedial alternatives. A proposed plan for
remedial action at OU 5 (now comprising Area 1, Area 31, and Area 52) was published
for public comment in October 1995.
4.0 COMMUNITY RELATIONS
The specific requirements for public participation pursuant to CERCLA Section 117(a),
as amended by SARA, include releasing the proposed plan to the public. The proposed
plan for OU 5 (including Areas 1, 31, and 52) was issued in October 1995, and an open
house and public meeting were held on October 24, 1995. The public comment period
expired on November 9, 1995. No comments were received on the proposed plan.
31620\9605.MO\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 11
CTO 0162
Documents pertaining to this investigation are available in the following information
centers:
Oak Harbor Library
7030 70th N.E.
Oak Harbor, Washington 98277
Phone: (360)675-5115
Sno-Isle Regional Library System
Coupeville Library
788 N.W. Alexander
Coupeville, Washington 98239
Phone: (360) 678-4911
NAS Whidbey Island Library (for fchose 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 Engineering Command
19917 Seventh Avenue N.E.
Poulsbo, Washington 98370
Phone: (360)396-0061
Community relations activities have established communication between the citizens
living near the site, other interested organizations, the Navy, the EPA, and Ecology. The
actions taken to satisfy the statutory requirements also provided a forum for citizen
involvement and input to the proposed plan and the ROD. These actions include the
following:
• Creation of a community relations plan
• Quarterly meetings of the Technical Review Committee (TRC), which
included representatives from the public and from other governmental
agencies
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 12
CTO 0162
• Since February 1994, monthly meetings of the Restoration Advisory Board
(RAB) (the function of a RAB is discussed below), which replaced the
TRC and provided additional public involvement in OU 5
• A public availability session, held in February 1994, during which
information was presented to citizens about the ongoing environmental
investigations
• An open house held May 1995 updating the public on the ongoing activities
on the projects at NAS Whidbey Island
• Newspaper, radio, television, and poster advertisements for the proposed
plan and public meeting
• A public meeting on October 24, 1995, to present the findings of OU 5
investigations and to receive comments on the proposed plan
In the National Defense Authorization Act for Fiscal Year 1995 (Senate Bill 2182),
Section 326(a), Assistance for Public Participation in Defense Environmental Restoration
Activities, the DoD was directed to establish RABs in lieu of TRCs. In January 1994,
NAS Whidbey Island became one of the first Navy facilities to establish a RAB.
The purposes of the RAB are the following:
• To act as a forum for the discussion and exchange of information between
the Navy, regulatory agencies, and the community on environmental
restoration topics
• To provide an opportunity for stakeholders to review progress and
participate in the decisionmaking process by reviewing and commenting on
actions and proposed actions involving releases or threatened releases at
the installation
• To serve as an outgrowth of the TRC concept by providing a more
comprehensive forum for discussing environmental cleanup issues and
providing a mechanism for RAB members to give advice as individuals
31620\9605.0*0\TEX7
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 13
CTO 0162
The RAB members include representatives from the Navy and regulatory agencies as
well as from civic, private, city government, and environmental activist groups. The NAS
Whidbey Island RAB, as currently staffed, has substantial representation from interested
environmental organizations.
The RAB has been involved in the review and comment process of all project
documents. In particular, this group participated in development of the OU 5 decision
documents. Members were briefed on and reviewed a draft of the proposed plan prior
to the public meeting and reviewed a draft copy of this ROD.
5.0 SCOPE AND ROLE OF OPERABLE UNITS
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, 2, and 3 have been selected and RODs have been finalized. For
OU 4 (at the Seaplane Base), the ROD was signed in 1993, cleanup actions were
completed in 1994, and the site was delisted from the NPL in September 1995. The
cleanup actions described in this ROD for OU 5 will mark the end of the Navy's
CERCLA investigation at NAS Whidbey Island. These cleanup actions address all
known current and potential risks to human health and the environment associated with
OU5.
The Navy is investigating whether past Navy activities at Area 31 have affected adjacent
privately owned property. In an effort to avoid delaying the timely cleanup of Area 31,
the Navy is addressing the adjacent property separately. The Navy is coordinating these
activities directly with the owner of the private property.
6.0 SUMMARY OF SITE CHARACTERISTICS
This section summarizes the physical characteristics and the nature and extent of
chemicals detected at OU 5.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 14
CTO 0162
6.1 PHYSICAL CHARACTERISTICS
The surface features, surface water hydrology, geology, and hydrogeology of the three
areas in OU 5 are described in the following subsections.
6.1.1 Area 1
Area 1 consists of approximately 6 acres bounded on the north by Area 52, on the south
by a marshy embayment, on the west by the Strait of Juan de Fuca, and on the east by
Saratoga Street and Ault Field. The area is vegetated with grasses and shrubs.
Surface Features
The topography of Area 1 consists of a series of manmade terraces that descends
approximately 30 feet from Saratoga Street to the beach. The Beach Landfill is located
in the terraced area. The site is incised by two east-west trending drainage swales, or
ditches. The northernmost swale forms the northern boundary of the landfill and
separates Area 1 from Area 52. The swale is heavily vegetated and varies in depth from
4 to 10 feet and in width from 3 to 10 feet. The second swale, which is located near the
middle of the landfill, consists of a wetland area that receives runoff from the outfall of a
24-inch storm sewer crossing under Saratoga Street. The storm sewer outfall discharges
storm drainage from lawns and paved areas east of Area 1. An unlined, naturally
vegetated ditch discharges water from the wetland to the Strait of Juan de Fuca. The
southern end of the Beach Landfill extends into a low-lying beach embayment. The
western edge of the landfill is bounded by a small bluff (5 to 10 feet high) that descends
to a relatively narrow beach consisting of fine to coarse sand and cobbles.
Vegetation covers the area except where wave action has eroded the toe of the bluff.
Construction debris, consisting primarily of concrete blocks and slabs and wooden
timbers, is visible along the beach in the toe of the landfill.
Surface Water Hydrology
The investigation of Area 1 was performed during dry weather conditions, when the
drainage swales were dry. At the time of the investigation, the wetland areas contained
small amounts of water; however, no surface water was discharging from these areas into
the Strait of Juan de Fuca. The sources of the water in the wetland in the middle of the
landfill were the storm sewer outfall that drains lawn irrigation from the field east of
31620N9605.040VTEX7
-------
HAS WHIDBEY ISLAM), OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 15
CTO 0162
Saratoga Street, and, possibly, groundwater seeps. The water in the wetland to the south
of the landfill is likely the result of groundwater seepage.
Geology
The stratigraphy beneath Area 1 consists of 11 to 22 feet of fill material that has been
placed over beach sands. The fill material consists of local borrow material from
construction of the base (brown silty clay and sandy silts with some sands and gravels),
concrete chunks, and debris. Localized layers of burnt debris are interbedded with the
borrow material. This debris consists of burnt paper, wood, concrete, roofing shingles,
bottles, metal scraps, and burnt practice-bomb casings. Debris layers vary in thickness
from 0.1 to 4 feet. The fill material is underlain by recent beach deposits consisting of
fine sand with a trace of gravel. The beach deposits are underlain by glacial deposits
consisting of dense sand and gravel deposits.
Hydrogeology
Area 1 and Area 52 are located adjacent to the Strait of Juan de Fuca, a tidally
influenced saltwater body. It is assumed that similar groundwater conditions exist at
Area 1 and Area 52 because the two areas had similar topography prior to the fill
placement, and they appear to have been filled with similar materials. A generalized
hydrogeologic profile, relevant to both Area 1 and Area 52, is presented in Figure 5.
Groundwater occurs under unconfined conditions within the beach deposits and glacial
sands and gravels beneath the fill. During seasonal wet periods, groundwater may rise
into the bottom of the fill materials.
Groundwater beneath the site is recharged by underflow from the area to the east and
by infiltration of precipitation falling on the site. Groundwater generally moves
northwesterly to the strait. Water level data from Area 52 wells indicate that upgradient
groundwater enters Area 1 at a relatively steep gradient and flattens out across the site.
Water table fluctuations may cause variations in the direction of local groundwater flow
where seasonal water table and daily tidal fluctuations affect the groundwater gradient.
Monitoring of groundwater levels in wells during a previous study of the Jet Engine Test
Cell showed that the shallow groundwater system along the beachfront is hydraulically
connected to the strait. Tidal data collected during the same study suggest that water
levels and the resulting groundwater gradients beneath the area vary in response to tidal
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 16
CTO 0162
fluctuations in the Strait of Juan de Fuca. However, the tidal effects are limited in
amplitude; measured water level fluctuations in wells along the beachfront were less than
0.5 foot.
As seen in Figure 5, the water table profile indicates the presence of a freshwater wedge
beneath the site. The shape and volume of the wedge likely vary in response to tidal
fluctuations and seasonal recharge. The interface, a zone where freshwater and saltwater
mixing occurs, forms as a result of the density contrast between fresh and salt water.
Because it is less dense than salt water, the fresh water forms a wedge above the salt
water. Mixing occurs as a result of head changes in the ocean because of tides, and
through seasonal head changes in the aquifer. Discharge of groundwater to the Strait
occurs in the intertidal zone.
6.1.2 Area 52
i
Area 52 is bounded on the west by the Strait of Juan de Fuca, on the east by Saratoga
Street, and on the south by Area 1.
Surface Features
Area 52 is located on a level terrace at the top of a 2- to 10-foot bluff that drops off to a
cobble beach and the Strait of Juan de Fuca to the west. Area 1 to the south is
separated from Area 52 by a deep swale. Most of Ault Field is located to the east. The
Jet Engine Test Cell area is paved, with the test cell building and associated support
facilities in the center of the site. The western unpaved portion of the area is
maintained as a volleyball court. The vegetation at Area 52 consists of grasses and
shrubs.
Geology
The stratigraphy beneath Area 52 is analogous to that of Area 1 (see Section 6.1.1) and
consists of 5 to 25 feet of fill material overlying 10 to 20 feet of recent beach deposits.
The beach deposits overlie glacial deposits consisting of dense sand and gravel.
Hydrogeology
The hydrogeology of Area 52 is analogous to that of Area 1 (see Section 6.1.1).
Groundwater beneath Area 52 occurs under unconfined conditions within the beach
31620\9605.040VTEXT
-------
ali
0 msl
0 40
1 1
80
I±=
160 0
=J t3
20
40
^
LEGEND
NOTES
1. Profile Adapted from Hart Crowser (199i)
2. Profile is a schematic representation o- sediment conditions.
Variations in the profile along the bluff re likely to exist.
3 Water table profile based on January r. I991,groundwater
measuremenis by Hart Crowser (199 • 2nd maximum water
table gradient of 0.005 It/It.
Horizontal Scale in Feet Vertical Scale in Feet
Vertical Exaggeration = 4X
Direction of Flow
Idealized Fresh Water/Salt Water Interlace
Mixing Zone
Glacial C^1-1--1^6) Deposits
Glacial (SAND and GRAVEL) Deposits
Recent (Loose SAND) Deposits
Fill Material
If1
II
Ss
i
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 19
CTO 0162
deposits and glacial sands and gravels beneath the fill. During seasonal high
groundwater conditions, the water table may intercept the base of the fill.
Groundwater generally flows west-northwest beneath the site and discharges to the Strait
of Juan de Fuca. Local reversal of the gradient has been observed during previous tidal
monitoring studies.
As seen in Figure 5, the water table profile indicates the presence of a freshwater wedge
beneath the site. The shape and volume of the wedge likely vary in response to tidal
fluctuations and seasonal recharge. The interface, a zone where freshwater and saltwater
mixing occurs, forms as a result of the density contrast between fresh and salt water.
Because it is less dense than salt water, the fresh water forms a wedge above the salt
water. Mixing occurs as a result of head changes in the ocean because of tides, and
through seasonal head changes in Jhe aquifer. Discharge of groundwater to the strait
occurs in the intertidal zone.
6.1.3 Area 31
Area 31 occupies approximately 20 acres oathe northern perimeter of the base.
Surface Features
Area 31 is located on nearly flat ground, sloping gently to the southwest. The principal
structure is the flat, square concrete burn pad, 50 feet on a side, near the center of the
area. The burn pad has a retaining lip and a drain in the middle. The drain connects to
a buried pipe that leads southwest from the pad to a buried oil/water separator and
discharges through a culvert under the hardstand road. The ditch beyond the culvert
drains into a topographically low area. A second ditch runs along the southern edge of
the training area and merges into the main ditch on the far side of the hardstand road.
There are several piles of ash from firefighting training activities that contain a variety of
materials, from dust- and grit-sized particles to gravel and recognizable aircraft parts.
Surface Water Hydrology
Surface water from a small portion of Area 31, in the vicinity of the former UST, flows
to the east into a low-lying marsh or wetland on private property (Figure 6). However,
surface water from most of Area 31 drains south and west onto Navy property. All
locations at Area 31 where surface soil contamination was found are within the zone that
31620\9605.040\TEXT
-------
A r
( y Marshy Area
__ Ridge Line (Row Divide)
Surface Water Flow Direction
Shallow Ditch
Elevation Contour Lines
(ft above msl)
Former
Underground
Storage Tank
CLEAN
COMPREHENSIVE
LONG-TERM ENVIRONMENTAL
ACTION NAVY
Figure 6
Surface Water Flow Directions-Area 31 and Adjacent Property
CT00162
Operable Unit 5
NAS Whidbey Island, WA
ROD
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 21
CTO 0162
drains south and west onto Navy property. Therefore, any erosional transport of
contaminated surface soil particles by surface water would not result in deposition of
contaminants off site.
Geology
The stratigraphy beneath Area 31 consists of Vashon glacial deposits overlying the
Whidbey Formation. The locations of two geologic cross sections are shown in Figure 7;
the cross sections are presented in Figures 8 and 9.
Vashon recessional outwash deposits at Area 31 generally consist of loose to medium-
dense, gravelly, silty sand with thin interbeds of sandy silt (units A and B in cross
sections). The total measured thickness of the recessional outwash unit ranges from
about 5 to 13 feet The silt lens (ijnit B) is up to 3 feet thick.
Below the recessional outwash are localized units of stiff silt and clay (unit C) and very
dense, silty, fine sand (unit D). Unit C, which ranges up to about 4 feet thick, may be a
silt and clay portion of the Vashon till. Unit D, which ranges up to 13 feet thick, consists
of hard, gravelly, sandy silt, which is typical of Vashon till.
Vashon advance outwash deposits (units E and F), which consist of dense to very dense,
clean to silty, fine to medium sand with occasional gravel lenses, underlie the recessional
outwash and till deposits. The thickness of the advance outwash at Area 31 varies from
approximately 30 to 45 feet.
The Whidbey Formation consists of the following, from top to bottom: hard silt
(unit G); medium to very dense, fine to medium sand (unit H); and very dense silt and
fine sand (unit I). The total drilled thickness is 53 feet. In Navy well 6, which was
drilled to 156 feet below ground surface (bgs), the Whidbey Formation may be greater
than 120 feet thick and consists of very fine to coarse sand with some silt and wood
(peat) material (unit J). Unit J is equivalent to units G, H, and I (and possibly older
units).
Hydrogeology
A single, shallow, unconfined aquifer was identified beneath Area 31 in the fine to
medium sand with some silt underlying the recessional outwash silty sand. This aquifer
is the same as the sea level aquifer encountered at Areas 1 and 52.
31620\9605.040\TEXT
-------
Approximate
Groundwater Flow
Direction in the
Shallow Unconfined
Aquifer
Boundary of Navy
Firefighting
Training Area
Monitoring Well
© Abandoned Navy Well
Soil Boring
Ash Pile or Areas of Ash
Approx. Location of Buried Piping
Shallow Ditch
* ~ -~ ~ Fence Line
Elevation Contour Lines (ft above MSL)
CT00162
Operable Unit 5
NAS Whidbey Island, WA
ROD
Figure 7
Location of Cross Sections - Area 31
COMPREHENSIVE
LONG-TERM ENVIRONMENTAL
ACTION NAVY
533162004-120-040496
-------
C AREA 31 Qt
North
Bend In
60-
F
... 40 -
,?!
uj 20 ~
Mean Sea Level 0 -~
-20-
-40-
~
-60-
-
•80-
-100-
Section
^
MW31-7A&B
A 'li^g^lS
?^^«fe^ :||!
C |
F
G
7-^fe*--— "^
H
*-*m®$m$Mlmm
LEGEND
A Loose to medium dense, Slty to clean SAND winsome Gravel
(Vasnon Recessional Outwasn and younger deposits; Includes
teraofunIB)
B Loose to medum dense, flne Sandy SILT
C SUM SLT and CLAY (Vashon Til or Outwasn)
D Very dense, Sityflne SANO with some Sandy SILT (Vashon
Advance Outwash antfor Til)
E Very dens* CJRAVa and SAND (Vashon Advance Outwash)
CLEAN
COMPREHENSIVE
LONG-TERM ENVIRONMENTAL
ACTION NAVY
5)iTifi?OOJ-ibfi-d40«i96
Bendln • South
Section
o>
MW3M
(N31-26)
MVW1'9A*B Dilch Oil/Water
Ag Separalor DHch Navy Welt *6
^. A IP- Z.^-^ I MW3M1 (Abandoned)
5":^ '^^^=—-^Z. — ^^4 "~~~~
^t^^r t
F F
^^v^,*^*^^ ~- '•
H
H
^a-sss^ 7
'
E^P SttorCtay
F Dense to very dense, flne to medium SAND win soms Sft, IJJlll Fine Sand and SH
trace Gravel (Vashon Advance Outwash) i \ _ ._. k _ . ^ .
1 ' | 1 Predominantly Sand or Gravel
0 Ham SILT (Whkt»yFofmaik)n) 2 Water LavelWentftedDurtnQDdfno
H Medkim to very derm, line to medium SANO (Whktey Formatfon) X s&flc Water Level (August 1 992)
1 Very dense SIT and fine SAND (Whkbey Formation) e Wefl Screen
J Sand (varying from very flne to coarse), some sIVcby, face peal 0 200
(Undnererllal units ol the Wrtdbey Formalkxi »nd poisbte •••••••CZZZIIZIIl
Double BM Drift) HORIZONTAL SCALE IN FEET
5X VERTICAL EXAGGERATION
F
J(Unh J It equrvaJent
to UnHs Q, H, and 1)
J
i
r *
- 40
" 20
- 0
- -20
- -40 .
"
- -eo
-
- -80
- -100
~ -120
Figures CTOOIB
Geologic Cross Section C-C'-Area 31 MAS wSy isSd, WA
ROD
-------
i|!
< o i
O
CD
o
O
o
en
en -n
c/>to"
CD C
O — «
=r. CD
9
o
o>
o>
CO
^ o
2*8 O
as;
i
Elevation m Feet (msl)
8
' fc
fe
8
I I I If I II
! II fl ! It
m
>
w
8
S
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 25
CTO 0162
The top of the shallow, unconfined aquifer is between 5 and 20 feet bgs. The base of
the aquifer was not reached; however, the sand may be as thick as 150 feet Localized
silt lenses overlying the fine to medium sand have created perched water zones, where
the potentiometric heads are substantially higher than those in the surrounding aquifer.
In Area 31, the water table surface ranged from 12.6 to 13.9 feet above mean sea level
(msl), and perched water was between 30 and 35 feet above msl. The August water
levels for some of the Area 31 wells are shown on the cross sections (Figures 8 and 9).
Although the flow direction and gradient for the perched water zones are unknown, the
approximate extent of these perched zones may be inferred from the limits of the fine-
grained units. At Area 31, water is perched above units B, C, and D (Vashon glacial
units).
It is likely that groundwater in the shallow, unconfined aquifer flowing south from
Area 31 eventually discharges through eastern Clover Valley to Dugualla Bay.
Groundwater would, therefore, generally follow the topography and surface water flow.
Following this hydraulic route, the eastern Navy base boundary is about 1.3 miles
downgradient of Area 31. As a result, impacts to groundwater quality at Area 31 could
potentially affect off-site water users at the eastern end of Clover Valley, where both
surface water and groundwater are used for agricultural purposes, and groundwater is
used for domestic drinking water. The nearest private well used for drinking water,
downgradient of Area 31, is approximately 1.3 miles away.
6.1,4 Groundwater Potability
The groundwater in the shallow aquifer at Areas 1 and 52 is not considered a potential
drinking water source based on the following assumptions:
• Potential future land uses indicate no reason to develop a domestic
drinking water well at Area 1 or Area 52. However, if such a well were
installed and operated, it is possible that saltwater intrusion would occur,
and the water would not be potable because of high salinity.
• The airfield will always serve as an airfield, even if the Navy discontinues
use of the base. Areas 1 and 52 are located immediately under the airfield
flight line, which precludes their use for future residential development.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 26
CTO 0162
• The existing domestic drinking water supply from the Anacortes pipeline is
available and will continue to be available for any future demand at
Areas 1 and 52.
At Area 31, it is possible that groundwater from the shallow aquifer could be used as a
future source of drinking water, although such use is unlikely. Groundwater quality at
Area 31 was therefore evaluated based on drinking water criteria.
6.2 NATURE AND EXTENT OF CONTAMINATION
Environmental media sampled during the OU 5 investigation include surface and
subsurface soil, groundwater, freshwater sediment, and surface water.
All of the chemicals detected at OU 5 were screened in three steps to focus on
chemicals with potential for human health or ecological risk.
In the first step, inorganics were screened against background concentrations. Any
inorganic that was at or below background was deleted from consideration. Inorganics
that are essential nutrients (aluminum, calcium, magnesium, potassium, iron, and sodium
in soils, sediments, and groundwater, and calcium, magnesium, potassium, and sodium in
surface water) were also eliminated.
The second screening step identified chemicals of potential concern (COPCs) by
screening the chemical concentrations against EPA Region 10 risk-based screening
concentrations (RBSCs). These RBSCs use a standard residential exposure assumption,
which is the most conservative exposure assumption. For chemicals in soil and sediment,
the RBSC designated by EPA is equivalent to a 10~7 cancer risk and a hazard quotient
(HQ) of 0.1 for noncancer effects. For chemicals in water, the RBSC designated by
EPA is equivalent to a 10"6 cancer risk and an HQ of 0.1 for noncancer effects. The
chemicals that exceeded both background concentrations and Region 10 RBSCs were
considered COPCs.
The COPCs were then evaluated in a third screening step to determine chemicals of
concern (COCs). Actual exposure scenarios that could occur at each site were evaluated
in the risk assessment. At Areas 1 and 52, actual exposure scenarios were used to
develop site-specific RBSCs, and detected concentrations of chemicals that exceeded
these site-specific RBSCs were considered COCs. At Area 31, actual exposure scenarios
31620\9605.040VTEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 27
CT00162
were used to develop numeric risk estimates, and any chemical presenting a 10"6 cancer
risk or an HQ of 0.1 for noncancer effects was considered a COC. At all three areas,
any chemical posing a potential ecological risk was also considered a COC, and any
chemical detected at concentrations above federal or state screening criteria was
considered a COC. Table 1 shows which screening criteria were used for each medium
at each site.
The specific methods used in the baseline risk assessment are discussed in detail in
Section 7. The following subsections describe the nature and extent of the COCs found
at each site.
62.1 Area 1
Sampling stations at Area 1 are sfyown in Figure 10. Table 2 summarizes the COCs
identified for Area 1, including the calculated background concentrations used for
comparison, the frequency of detections above background, and the range of detected
concentrations above background.
Soil
Soil samples were collected at Area 1 from four soil borings and two test pits. Surface
and subsurface samples were collected from the soil borings. Only subsurface samples
were collected from the test pits. Soil samples were analyzed for target analyte list
(TAL) inorganics and target compound list (TCL) pesticides/polychlorinated biphenyls
(PCBs), volatile organic compounds (VOCs), semivolatile organic compounds (SVOCs),
and total petroleum hydrocarbons (TPH).
Petroleum hydrocarbons, copper, lead, and zinc were identified as COCs in Area 1 soils.
Concentrations of petroleum hydrocarbons exceeded the Model Toxics Control Act
(MTCA) Method A soil cleanup level in one subsurface soil sample collected from
Station SB-1 at a depth of 5 to 6.5 feet bgs. MTCA Method A soil cleanup levels for
TPH are for the protection of groundwater and not for the protection of human health.
Copper, lead, and zinc concentrations did not exceed regulatory criteria, but these
inorganics were identified as ecological risk contributors because they exceeded the site-
specific ecological RBSCs. However, the ecological risk assessment concluded that
actual risks from copper, lead, and zinc were highly uncertain.
No COCs in soil exceeded human health site-specific RBSCs.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0162
Final Record of Decision
Revision No.: 0
Date: 05/21/96
Page 28
Table 1
Screening Criteria Used at OU 5
Environmental
Mtdium
Washington
M*r!rie Water
Quality Standards
(ACttte & CtUttttk}
Federal
IVtarinfe Wa W
Quality Criteria
(A
-------
Potential Bum Pit Area
24" Storm Drain Outfall
r
/ Paved ///
\. >
\/
Straff of Juan cte ft/ca
Potential Burn Pit Area
Storm Drain Manhole
Presumed
Groundwater Flow
LEGEND
— - - — - Drainage Ditch
A Surface Water Sampling Location (SW001)
Monitoring Well (MW-18)
Test Pit/Standpipe Location (TP103/MW103)'
Sediment Sampling Location (SS-1)
Sandpoint(SP-l)
• Soil Sample (SB-4)
" Land Surface Elevation Contour
Approximate Landfill Boundary
Approximate Location
100 200
Scale in Feet
Contours in Feet
CLEAN
COMPREHENSIVE
LONG-TERM ENVIRONMENTAL
ACTION NAVY
Figure 10
Area 1 Sampling Locations
CT00162
Operable Unit 5
MAS Whidbey Island, WA
ROD
S33162004-4-0404 96
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0162
Final Record of Decision
Revision No.: 0
Date: 05/21/96
Page 30
Table 2
Chemicals of Concern at Area 1
Cfe«wfe«l
Background
Coflc^fltwrtlott
Irwjtieney «f
Refections
Above
Backgrownf
Ranged Detections :
Above Bacfcgiwind j
friinimum | Maximum
Reasons for Selection *&* COP
Major Risk Contributors*
fttimaa
£«iiogkaJ
Screening
Criteria
&K£gfitifiyi£6- '
SolMmg/kgj - x- -
Copper
Lead
Zinc
TPH
Sutrface Walw
-------
HAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 31
CTO 0162
Surface Water
Surface water samples were collected from seven freshwater sampling stations at Area 1,
including the wetlands, a seep, a downgradient drainage ditch, and an upgradient storm
sewer. Surface water samples were analyzed for TAL inorganics (total and dissolved);
TCL pesticides/PCBs, VOCs, and SVOCs; and TPH.
Lead, mercury, zinc, PCBs (Aroclors 1254 and 1260), and petroleum hydrocarbons were
identified as COCs in Area 1 surface water based on exceedances of state freshwater
quality standards. Exceedances occurred within the wetlands and in upgradient
stormwater, but not in downgradient drainage from the wetlands. The source of these
chemicals appears to be upgradient storm drainage. The PCBs were detected in the
sample from the upgradient storm tfrain, and the other COCs found in the wetlands are
common pollutants in urban runoff. The wetlands remove these chemicals from surface
water through natural processes such as adsorption, sedimentation, and biodegradation.
No COCs in surface water exceeded human health site-specific RBSCs or were identified
as ecological risk contributors.
Sediments
Freshwater sediment samples were collected from three sampling stations within the
Area 1 wetlands. Sediment samples were analyzed for TAL inorganics; TCL
pesticides/PCBs, VOCs, and SVOCs; and TPH.
Lead and PCBs (Aroclor 1254) were identified as COCs in freshwater sediment samples,
based on exceedances of to-be-considered (TBC) guidelines. There are no federal or
state standards for freshwater sediments; MTCA soil cleanup levels were used as
screening criteria to identify COCs. Concentrations of lead and PCBs exceeded MTCA
soil cleanup levels in one sample collected at Station SS-2. The source of these
chemicals appears to be upgradient storm drainage.
No COCs in sediment exceeded human health site-specific RBSCs or were identified as
ecological risk contributors.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 32
CTO 0162
Groundwater
Groundwater samples were collected from two monitoring wells within the Area 1
landfill and from five intertidal sandpoint wells along the eastern shoreline of Area 1.
Groundwater discharges to marine surface water in the intertidal zone. Because
groundwater at Area 1 is not a current or potential future source of drinking water,
groundwater quality was evaluated based on the protection of nearby marine surface
water. Groundwater samples were analyzed for TAL inorganics (total and dissolved);
TCL pesticides/PCBs, VOCs, and SVOCs; and TPH.
State marine water quality criteria for the following inorganics are based on the dissolved
form: cadmium, copper, lead, nickel, silver, and zinc. For all other chemicals, total
concentrations are used.
Dissolved zinc, total cyanide, 1,1-dtchloroethene, and bis(2-ethylhexyl)phthalate were
identified as COCs in Area 1 groundwater based on exceedances of State marine water
quality standards. Dissolved zinc exceeded State marine water quality standards in one
of three samples, cyanide in two of three samples, 1,1-dichloroethene in one of six
samples, and bis(2-ethylhexyl)phthalate in three of nine samples. The accuracy of the
cyanide results is suspect because the samples were not properly collected or preserved.
Actual concentrations of cyanide in the groundwater may be higher or lower than these
cyanide analyses indicated.
Exceedances of these screening criteria indicate some potential for ecological effects.
Although the concentrations of these four chemicals in groundwater exceed marine water
quality criteria, actual ecological effects in the intertidal zone are uncertain. A biological
survey revealed normal communities of plants and animals in the intertidal zone, with no
apparent impacts from the landfill Some attenuation occurs before groundwater
discharges to marine surface water as a result of vertical dispersion, tidal flushing, and
contaminant loss mechanisms. A very large degree of dilution occurs immediately after
groundwater discharges to the intertidal area as a result of mechanical mixing with
marine surface water. However, analytical solutions could not be used to quantify these
effects because of the complexity of the hydrogeology.
Based on the detected concentrations of cyanide in two inland monitoring wells and
hydrogeological information gathered during the RI, the mass loading of cyanide being
discharged from Area 1 to the marine environment is estimated at approximately
0.5 pound per year. Because cyanide rapidly volatilizes or biodegrades in surface water
31620\9605.(HO\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0162
Final Record of Decision
Revision No.: 0
Date: 05/21/96
Page 33
and does not bioaccumulate, the relatively low concentrations and mass loadings of
cyanide are not expected to affect the marine environment or other ecological receptors.
No COCs in Area 1 groundwater exceeded human health site-specific RBSCs.
622 Area 52
Sampling stations at Area 52 are shown in Figure 11. Table 3 provides a summary of
the COCs identified for Area 52.
Table 3
Chemicals of Concern at Area 52
Chemical
BaekgroHitt!
OuKfeitfrati^rt
Smiley
-------
MW-18
Monitoring Well (MW-11)
Sandpoint(SP-l)
Sediment Sample (SS-1)
100
Scale in Feet
200
CLEAN
COMPREHENSIVE
LONG-TEFlM ENVIRONMENTAL
ACTION NAVY
Figure 11
Area 52 Sampling Locations
CT00162
Operable Unit 5
NAS Whidbey Island, WA
ROD
533162OS-040496
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 35
CTO 0162
Soil
Subsurface soil samples were collected from 15 stations (MW-10 through MW-24) at
Area 52. Samples from MW-10 through MW-21 were analyzed for TPH; samples from
MW-21 through MW-23 were analyzed for TAL inorganics and TCL pesticides/PCBs,
VOCs, and SVOCs. Additionally, six samples were collected from a soil pile on site and
analyzed for TPH.
Petroleum hydrocarbons were the only COC identified for Area 52 soils, based on
exceedances of MTCA soil cleanup levels.. The exceedances occurred in subsurface soils
at MW-11, MW-12, MW-14, MW-15, MW-16, and MW-19 at depths of 10 to 16.5 feet
bgs. The source of the petroleum is free-phase product that is floating on the
groundwater. Subsurface soil samples collected in areas of suspected solvent disposal
(MW-22, MW-23, and MW-24) did^ not contain any chemicals at concentrations above
MTCA soil cleanup levels. Petroleum hydrocarbons in the stockpiled soil on site did not
exceed MTCA soil cleanup levels.
No COCs in soil exceeded human health site-specific RBSCs. Ecological risks were not
evaluated for soil because it is an industrial area, most of which is paved, and subsurface
soils are not available to organisms.
Groundwater
Groundwater samples were collected from five intertidal sandpoint wells along the
eastern shoreline of Area 52, and analyzed for benzene, toluene, ethylbenzene, and
xylenes (BTEX) and chlorinated benzenes. In addition to the sandpoint wells, a total of
24 monitoring wells were installed at Area 52. Groundwater samples were generally
analyzed for VOCs, SVOCs, polycyclic aromatic hydrocarbons (PAHs), and TPH. As
with Area 1, groundwater at Area 52 discharges to marine surface water in the intertidal
zone. Groundwater quality was therefore evaluated based on the protection of nearby
marine surface water.
Floating petroleum product (jet petroleum fuel #5, or JP-5) was observed on the
groundwater at Area 52. The apparent thickness of the floating petroleum product has
been measured in monitoring wells from 1990 through 1995. The petroleum product 0.5-
foot-thickness contour for January 23, 1995, is shown in Figure 12, along with the
contour for petroleum product of the same thickness on May 18, 1990. The thickness of
floating petroleum product was greater than 0.5 foot in three small, distinct locations in
31620\9605.040\TEXT
-------
Beach
Monitoring Well
EW"2 (•) Extraction Well
Approximate Product Thickness Isocontours,
January 23,1995
Approximate Product Thickness Isocontours,
May 18,1990
Estimated
Notes:
1. The following monitoring wells at Area 52 are not
/ shown because they are not screened across the
water table surface: MW-8, MW-15, MW-22,
MW-23, and MW-24.
2. Free product was removed from EW-1, EW-2, and
EW-3 on December 7,1994, during the treatability
test.
cc
o
100
Scale in Feet
CLEAN
COMPREHENSIVE
LONG-TERM ENVIRONMENTAL
ACTION NAVY
Figure 12
Area 52-Apparent Thickness of Floating Petroleum
Product Measured in Monitoring Wells, January 23, 1995,
and May 18, 1990
CT00162
Operable Unit 5
NAS Whidbey Island, WA
ROD
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 37
CTO 0162
January 1995. Measurements made 5 years earlier, on May 18, 1990, indicated that the
thickness of floating petroleum product was greater than 0.5 foot in most of the wells at
Area 52, covering an area of about 4 acres. These measurements indicate that the
thickness of the floating petroleum product is diminishing over time, and the plume
appears to be breaking up. In December 1994, a treatability test was conducted to
extract groundwater and floating petroleum product at the water table surface. Active
pumping was used in three extraction wells. The results of this test demonstrated that
the floating petroleum product was not recoverable by active pumping.
Although floating petroleum product was not observed in the intertidal groundwater
wells and State marine water quality standards were not exceeded, xylenes were detected
at concentrations below 1 /*g/L in intertidal groundwater wells SP-4, SP-5, and SP-6.
This indicates that the more mobile constituents of the floating petroleum product are
discharging to the intertidal zone. v If the floating petroleum product on groundwater
does discharge to surface water, this would violate Washington State water pollution
control laws.
Vinyl chloride, PAHs, and petroleum hydrocarbons were identified as COCs in Area 52
groundwater, based on exceedances of marine surface water regulatory criteria. Vinyl
chloride occurred in groundwater samples collected from MW-3, MW-4, MW-5, and
MW-13, with the highest concentrations and most frequent detections at MW-4. These
wells are all screened at the top of the aquifer. The data indicate that the source of
vinyl chloride is near MW-4, and that vinyl chloride concentrations decrease away from
MW-4. PAHs were detected above regulatory criteria in two samples. The floating
petroleum product is the likely source of the PAH compounds in groundwater.
Monitoring wells MW-22, MW-23, and MW-24 were installed in areas of suspected
solvent disposal and were screened at the base of the aquifer to allow monitoring for
heavier free-phase or dissolved chlorinated solvents (chlorinated VOCs). No chlorinated
VOCs were detected in water samples collected from MW-22, MW-23, and MW-24,
indicating that pools of free-phase chlorinated solvent are not present at the base of the
aquifer.
Bis(2-ethylhexyl)phthalate was detected above regulatory criteria in seven samples and in
a laboratory blank. Because bis(2-ethylhexyl)phthalate is a common laboratory
contaminant and is not associated with historical activities at this site, it is not considered
aCOC
31620\9605.CMO\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 38
CTO 0162
The COCs in groundwater could pose ecological risk if they exceed State marine water
quality standards at the point of groundwater discharge (i.e., in the intertidal zone). The
existing data indicate that this is not the case. However, floating petroleum product
could pose ecological risks if it migrates to surface water.
No COCs in groundwater exceeded human health site-specific RBSCs.
6.23 Area 31
Three phases of environmental sampling have occurred at Area 31. Phase I and II
sampling stations at Area 31 are shown in Figure 13. During the OU 3 RI, Phase I
(June to August 1992) and Phase II (December 1992) involved the collection of surface
and subsurface soil, groundwater, and ditch sediment samples. Phase I and Phase II
information was used in the risk assessment. Table 4 summarizes the COCs identified
for Area 31 during Phase I and Pbfese IL Three additional investigations (denoted
Phase III) were later conducted. First, in September and October 1994, the 4,000-gallon
UST was removed from Area 31, and subsurface soil samples were collected near the
UST and its associated piping. Second, in January and February 1995, a construction
delineation sampling program was conducted involving (1) surface soil sampling near the
burn pad and the oil/water separator, (2) subsurface soil sampling near the oil/water
separator, (3) removal of PCB-contaminated surface soils, along with confirmation
sampling of surface soils, and (4) groundwater sampling near the oil/water separator.
Third, in the fall of 1995, additional soil and groundwater samples were collected from
three monitoring wells/boreholes in the vicinity of the former UST (which was removed
in September and October 1994). Table 5 summarizes the COCs identified at Area 31
during the Phase EQ investigations. Because the Phase III data were collected after the
risk assessment was conducted, the Phase III data are not included in risk calculations.
Surface and Subsurface Soil
A total of 82 surface and subsurface soil samples (including 2 ditch sediment samples)
were collected at .Area 31 during Phase I of the RI. During Phase III, surface soil
samples were collected from an additional five stations in the area of the PCB removal
action (near Station 31-22) and from 33 stations around the burn pad and oil/water
separator. Also during Phase III, subsurface soil samples were collected from 18 borings
near the oil/water separator and 7 stations near the UST and associated piping. Surface
and subsurface soil samples were also collected from three monitoring well boreholes
31620\9605.040\TEXT
-------
Groundwater Monitoring Well
Surface Soil Sampling Location
Soil Boring
Approx. Location of Buried Piping
Shallow Ditch
» ~~ ~* ~* pence yne
Elevation Contour Lines (ft above msl)
Boundary of Navy
Freighting '
Training Area
SB31-7A
MW31-7A
MW31-7B
ows-6 e m.-T.
j \ SS31-8 i vSB31-17
OWS-9X SB31-19 j
^•Z:_§B&
SS31-27
(1,350 tt west
ofMW31-11)
Note: Phase III soil sampling locations not shown.
CLEAN
COMPREHENSIVE
LONG-TERM ENVIRONMENTAL
ACTION NAVY
CT00162
Operable Unit 5
NAS Whidbey island, WA
ROD
Figure 13
Area 31 Sampling Locations
533162004-112-040496
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0162
Final Record of Decision
Revision No.: 0
Date: 05/21/96
Page 40
Table 4
Chemicals of Concern at Area 31
(Phase I and Phase II—Included in Risk Assessment)
<£S2L
Frequency
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 41
CTO 0162
Table 4 (Continued)
Chemicals of Concern at Area 31
(Phase I and Phase II—Included in Risk Assessment)
TEC Toxicity equivalency concentration (individual dioxins/furans concentrations were converted to equivalent concentrations
of 23,7,8-tetrachlorodibcnzo-p-dioxin using EPA's toxicity equivalency factors [U.S. EPA 19895])
TPH Total petroleum hydrocarbons
WA MCL Washington State Maximum Contaminant Levels (WAC 246-290)
pg/L Picograms per liter
31620\9605.040\TBL^4
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0162
Final Record of Decision
Revision No.: 0
Date: 05/21/96
Page 42
Table 5
Chemicals of Concern at Area 31
(Phase HI—Post Risk Assessment)
Otemical
Background j
Ckmcentratkm j
foeqaeneyof '•
Itetedfcti* i
Afcw* \
Background' ;
Range *f Detections
Afc
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 43
CTO 0162
near the UST. Soil samples were analyzed for TAL inorganics; TCL pesticides/PCBs,
VOCs, and SVOCs; dioxins/furans; and TPH.
Beryllium, lead, indeno(l,2,3-cd)pyrene, PCBs (Aroclor 1260), dioxins, and petroleum
hydrocarbons were identified as COCs in Area 31 soils. Beryllium exceeded the MTCA
Method A soil cleanup level in 21 of 81 surface and subsurface samples; however, no
clear distribution pattern was evident, and the maximum detected concentration was only
1.7 times the background concentration. Lead exceeded the MTCA Method A soil
cleanup level in 2 of 71 samples. The lead exceedances occurred in a surface soil sample
collected at Station 31-8 and a ditch sediment sample collected at Station 31-12. The
PAH indeno(l,2,3-cd)pyrene exceeded the MTCA Method B soil cleanup level in 3 of 70
samples. The PAH exceedances occurred in surface soil samples collected near the burn
pad at Stations 31-6, 31-8, and 31-16. The PCB Aroclor 1260 exceeded the MTCA
Method B soil cleanup level in 7 of 87 samples. The PCB exceedances occurred in
surface soil samples collected at Stations 31-6, 31-14, 31-17, and 31-22. In Phase HI, a
soil removal action was conducted at Station 31-22, where the highest PCB concentration
was found. Approximately 2 cubic yards of soil were removed. However, three of the
five confirmation samples from the excavated area still exceeded MTCA Method B soil
cleanup level of 0.13 mg/kg. The maximum detected PCB concentration in the
confirmation samples was 2.3 mg/kg. Dioxins exceeded the MTCA Method B soil
cleanup level in 8 of 17 samples. The dioxin exceedances occurred in surface soil
samples collected near the burn pad at Stations 31-6, 31-7A, and 31-8. Petroleum
hydrocarbons exceeded the MTCA Method A soil cleanup level in a total of 22 surface
and 35 subsurface soil samples. Petroleum hydrocarbons were found in surface soils
near the burn pad, near the oil/water separator, and downgradient of the oil/water
separator. Petroleum hydrocarbons were found in subsurface soils near the burn pad,
the oil/water separator, and the UST.
Lead and dioxins in surface soil were identified as potential ecological risk contributors.
As will be discussed in Section 7, potential ecological risks are limited to the masked
shrew.
Lead was identified as a human health COC in Area 31 ditch sediment because of one
detection above the EPA soil action level. This detection occurred in surface sediment
sample SD-12, immediately adjacent to an ash pile.
31620\9605.040\T£XT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 44
CTO 0162
Ash
Three ash samples (the by-product materials of fire training activities) were collected
from Stations 31-12 and 31-15. Ash samples were analyzed for TAL inorganics, TCL
pesticides/PCBs, VOCs, and SVOCs, dioxins/furans, and TPH. One ash sample was
analyzed for toxicity characteristics leaching procedure (TCLP) parameters.
Only lead was identified as a COC in ash, based on exceedances of the MTCA
Method A soil cleanup level, which was used as a screening level for ash. Lead
exceeded the MTCA Method A soil cleanup level in two of three ash samples. No
chemicals exceeded regulatory levels in the TCLP extract sample.
Lead was identified as a human health COC in Area 31 ash because of one detection
above the EPA soil action level. This detection occurred in ash sample PR 31-12. The
ash was not evaluated for ecological risk.
Groundwater
A total of 23 groundwater monitoring wells were sampled one or more times during the
three phases of field investigations at Area 31. Eighteen of the wells were screened in
the shallow (sea level) aquifer. Five of the wells (MW31-3, MW31-5, MW31-31,
MW31-32, and MW31-33) were screened in the perched aquifer. Although the perched
aquifer is not a potential source of drinking water, it likely drains to the shallow aquifer
beneath it. Because groundwater from the shallow aquifer at Area 31 is a potential
source of drinking water, the analytical results from all groundwater samples were
compared to drinking water screening criteria (maximum contaminant levels [MCLs] and
MTCA Method B groundwater cleanup levels). Groundwater samples were analyzed for
TAL inorganics (total and dissolved); TCL pesticides/PCBs, VOCs, and SVOCs; dioxins/
furans; and TPH.
Floating petroleum product was found on shallow aquifer groundwater near the
oil/water separator in monitoring well MW 31-9A. Borings completed in the Phase III
field investigation verified the limits of the petroleum near the oil/water separator.
Additionally, some free-phase petroleum was found floating on perched aquifer
groundwater during removal of the UST in the Phase III field investigation. The
approximate limits of the floating petroleum product plume near the oil/water separator
are shown in Figure 14.
31620\9605.040\TEXT
-------
Approximate
Groundwater
Flow Direction
in the Shallow
Unconfined
Aquifer
LEGEND:
Floating Petroleum Product
Dissolved Organic COCs
(Includes one or more-of the
following):
•TPH>1000jig/L
•VinylChloride>0.02
• Benzene >1.5 jto/L
• Pentachlorophenoi >0.73 jig/L
•Aroclor1260>0.011 jig/L
• Dioxins >0.58 pg/L
A.
* Dissolved Manganese
» •• • ^ > Backaround /125 uc
Background (\ 25 ug/L)
Note: Inorganic data presented are
from Phase I, II, and III data.
Groundwater Monitoring Well
Location and Label
\ MW31-11®
\.
CT00162
Operable Unit 5
NAS Whidbey Island, WA
ROD
Figure 14
COCs in Area 31 Groundwater - Shallow Unconfined Aquifer
COMPREHENSIVE
LONG-TERM ENVIRONMENTAL
ACTION NAVY
533162004-1003-051596
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 46
CTO 0162
As shown in Tables 4 and 5, a total of 13 COCs were identified in Area 31 groundwater:
the inorganics beryllium, lead, manganese, and mercury, and the organics PCBs (Aroclor
1260), benzene, dioxins, naphthalene, pentachlorophenol, petroleum hydrocarbons,
styrene, toluene, and vinyl chloride. In Table 4, some of the maximum detected values
for COCs in groundwater are attributable to a groundwater sample collected from MW
31-9A during Phase I. This well contained floating petroleum product, and the
groundwater sample contained a sheen of petroleum that influenced the analytical
results. Therefore, results from this sample are not representative of actual groundwater
quality. The affected results are indicted by a footnote in the table, and the next highest
detection is presented as a more accurate representation of groundwater quality.
Figure 14 shows the approximate limits of the floating petroleum product, dissolved
manganese, and other organic COCs in the shallow unconfined aquifer. With the
exception of the inorganics beryllium and manganese, each of the COCs in groundwater
exceeded drinking water screening1 criteria near the oil/water separator and/or the UST
and are associated with petroleum floating on the groundwater in these locations. The
COCs associated with the petroleum exceeded drinking water screening criteria in wells
immediately downgradient of the oil/water separator.
Bis(2-ethylhexyl)phthalate was detected above regulatory criteria in a total of two
groundwater samples at Area 31. Because bis(2-ethylhexyl)phthalate is a common
laboratory contaminant and is not associated with historical activities at this site, it is not
considered a COC.
Beryllium does not appear to be associated with petroleum floating on the groundwater.
Total beryllium occurred in 1 of 34 samples and dissolved beryllium occurred in 1 of 34
samples. The detections of total and dissolved beryllium occurred at stations OWS-8 and
MW31-4, respectively. No known sources of beryllium exist. Beryllium occurred in
Area 31 soils at concentrations no greater than 1.7 times the calculated background
concentration.
Manganese exceeded drinking water screening criteria and background concentrations in
15 of 34 total analyses and 21 of 34 dissolved analyses. The approximate limits of the
dissolved manganese plume in the shallow, unconfined aquifer are shown in Figure 14.
The presence of petroleum in subsurface soils may be creating reducing conditions,
which can cause partitioning of manganese from soil to groundwater. The downgradient
extent of the dissolved manganese plume has not yet been defined. Future remediation
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 47
CTO 0162
of the petroleum constituents in soil and groundwater may shift the groundwater to
oxidizing conditions, causing the manganese to precipitate out of the groundwater.
Manganese was identified as a human health COC in the risk assessment based on
potential future use of groundwater as drinking water. Also, petroleum was identified as
a human health COC based on the assumption that floating petroleum product would
pose a human health risk if drinking water wells were developed at Area 31.
No ecological COCs were identified for Area 31 groundwater.
7.0 SUMMARY OF SITE RISKS
Human health and ecological risk assessments were conducted as part of the RI of OU 5
to evaluate current and potential future risks associated with exposures to detected
chemicals. These risk assessments indicate the risks that could exist if no remedial
actions were taken, considering not only current land uses but also potential future uses,
The results of the risk assessments were used in evaluating the need for remedial action
at Area 1, Area 52, and Area 31. A summary of the procedures and findings of the
human health and ecological risk assessments is presented in the following subsections.
7.1 HUMAN HEALTH RISK ASSESSMENT
Focused human health risk assessments were conducted for Area 1 and Area 52, and a
baseline human health risk assessment was conducted for Area 31. The first step of both
types of human health risk assessments is chemical screening to identify COPCs. This is
accomplished by comparing detected concentrations against background concentrations
and EPA Region 10 RBSCs for residential use. In the baseline human health risk
assessment for Area 31, after identification of COPCs, an exposure assessment and a
toxicity assessment were used to calculate quantitative risk estimates for each chemical in
each medium. As discussed in Section 6, the original human health risk assessment at
Area 31 includes only Phase I and Phase II data. A brief review of the data collected
after the Phase I and II investigations was performed and is discussed in Section 7.1.5.
In the focused human health risk assessment for Area 1 and Area 52, an exposure
assessment was used to develop site-specific RBSCs. The assumptions used in
developing the site-specific RBSCs are discussed in Section 7.1.2. Detected
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 48
CTO 0162
concentrations of COPCs were compared against the site-specific RBSCs to determine if
the potential existed for risk and what the general magnitude of the risk might be. The
COPCs exceeding the site-specific RBSCs at Areas 1 and 52 and the COPCs showing
unacceptable risk in the baseline risk assessment for Area 31 are considered COCs.
Specific methods for each step (chemical screening, exposure assessment, toxicity
assessment, and risk characterization) are discussed in the following subsections.
7.1.1 Chemical Screening
The analytical results for each area at OU 5 were evaluated by a number of initial
screening steps to identify COPCs. These COPCs were carried through the remainder of
the risk assessment to quantify risks at OU 5 and to determine the chemicals that
contribute most significantly to overall site risks. The chemical screening steps used to
establish COPCs included the following:
$
• Sample grouping. For each environmental medium, samples were selected
that were most representative for a particular exposure pathway. For
example, analytical results for chemicals in soil samples from 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 surface by future construction
activities.
• Data validation. The quality of the data was evaluated, in accordance with
EPA guidance, to assess whether each chemical result was suitable for use
in the risk assessment. Data rejected because of inadequate quality were
not carried forward in the quantitative risk assessment.
• Nondetected chemicals. If a chemical was not detected in any of the
samples for a particular medium, the chemical was eliminated from further
consideration in the risk assessment
• Essential nutrients. Certain inorganic chemicals were not included in the
risk calculations because they are essential nutrients that are either
nontoxic or toxic at only high concentrations. This screening was in
accordance with EPA guidance, which approves of eliminating such
nutrients from the human health risk assessment.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 49
CTO0162
• Toxicity. The maximum detected concentrations in each medium were
compared with RBSCs for residential use developed by EPA Region 10.
For chemicals in water, the RBSC designated by EPA corresponds to a 10"6
risk level for cancer effects and an HQ of 0.1 for noncancer effects. For
soil and sediment, the RBSC is equivalent to a 10"7 cancer risk and an HQ
of 0.1. These RBSCs represent conservative risk levels so that significant
risk-causing chemicals will not be screened out.
• Background. Inorganic chemical concentrations that were not eliminated
by comparison to RBSCs were compared with background concentrations
to determine whether they were present on site at elevated levels.
Background data for inorganics were used to screen on-site chemicals
because inorganics are naturally occurring components of environmental
media (i.e., soils anc| ground water). Background screening was not
conducted for organic chemicals because most of these chemicals are not
normally found in environmental media.
All chemicals that still remained as COPCs following the chemical screening were
further evaluated in the risk assessment.
7.1.2 Exposure Assessment
The purpose of the exposure assessment was to quantify potential human contact with
COPCs identified at the site. This was accomplished by identifying the exposure media,
the potentially exposed populations (based on current and future land uses),^and the
routes of exposure; and by quantifying the human intake of chemicals for these media,
populations, and exposure routes. The exposures that were evaluated are summarized in
Table 6.
Potentially exposed populations (receptors) and exposure routes (pathways) were
identified for current and potential future land uses for each of three areas in OU 5.
The populations that were considered at each area included one or more of the
following: current on-site workers, future industrial workers, future recreational visitors,
and future residents. Exposure pathways pertinent to each area, population, and medium
are identified in Table 6.
In order to calculate the human intake of chemicals, exposure point concentrations must
be estimated. Exposure point concentrations are the concentrations of each chemical to
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0162
Final Record of Decision
Revision No.: 0
Date: 05/21/96
Page 50
Table 6
Human Exposure Models Selected to Evaluate Potential
Risks From Chemicals at OU 5
Efcvirodtrtfcfctal
Medium
Soil
Sediment
Surface water
Groundwater
Are*l*
Future R^reatioaal Visitor
JNG
X
X
X
^m*L
X
X
X
oc
Future Industrial Worker
mo
X
INtt
X
PC
Am $2*
Future Industrial Worker
ING
X
LlRS,,,
X
DC
Area 31*
Curmrt Qtt-Sli* WorJcer
HU
X
•\m
X
IK;
X
Future Re^ld^it
1NQ
X
X
INK
X
X
DC
X
X
"Screening-level risk assessment, using the EPA default RBSCs
bBasclinc risk assessment
Notes:
ING Ingestion
INH Inhalation
DC Dermal contact
31620\9605.040\TBL-6
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 51
CTO 0162
which an individual may potentially be exposed for each medium at the 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 expected at 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 lesser of the
maximum detected concentration or the 95 percent upper confidence limit (95UCL) on
the arithmetic mean.
The average exposure scenario was evaluated to allow a comparison with the RME. The
average exposure scenario is intended to be more representative of likely human
exposures at the site. The average1 exposure point concentrations were calculated as an
arithmetic mean of the chemical results for a particular medium.
In calculating exposure point concentrations, a value of one-half the sample quantitation
limit was used for samples in which a particular chemical was not detected. This
procedure is designed to avoid underestimating risks. To avoid overestimation, this
procedure was not applied to samples with abnormally high quantitation limits. The
approach used to screen unusually high detection limit data from the qualitative risk
assessment consisted of first identifying detection limits that were elevated substantially
above the typical detection limits for a given chemical 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 realistic exposure point concentrations.
Estimates of potential human intake of chemicals for each exposure pathway were
calculated by combining exposure point concentrations with pathway-specific exposure
assumptions (for 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
and site-specific exposure assumptions. More conservative exposure parameters were
used to calculate RME chemical intakes than were used to calculate average intakes.
The exposure parameters used at OU 5 are shown in Table 7.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0162
Final Record of Decision
Revision No.: 0
Date: 05/21/96
Page 52
Table 7
Exposure Parameters Used in Human Health Risk Assessment at OU 5
Expostih?
Pathway
Dermal Contact
with
Soil/Sediment
Parameter
Exposure
Frequency
Contact Rate
Skin Surface
Area
Units
days/yr
mg/cm3
cm2
Area 1
%m
Scenario*
NA
NA
Reference
Area 52
RME
Scenario*
NA
NA
JBteJtereitwe ;
Am 31
Average Scenarfo*
Worker 50 (soil)
Resident 275
(soil)
Resident 10
(sediment)
Worker 1
Resident 0.6
Worker 1,980
Resident 1,900
RMfc Scenario4 :
Worker 50 (soil)
Resident 350
(soil)
Resident 20
(sediment)
Worker 1
Resident 1
Worker 2,120
Adult resident
3,190 (soil)
Adult resident
5,000 (sediment)
Child resident
3,900 (sediment)
Iteferenee
BPJ
BPJ
BPJ
BPJ
BPJ
EFH 1989
31620\9605.040\TBL-7
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0162
Final Record of Decision
Revision No.: 0
Date: 05/21/96
Page 53
Table 7 (Continued)
Exposure Parameters Used in Human Health Risk Assessment at OU 5
Exposure
Pathway w
Soil/Sediment
Ingestion
Dermal
Exposure to
Surface Water
Parameter
Exposure
Frequency
Ingestion Rate
Exposure
Frequency
Exposure Time
Skin Surface
Area
IfnitS
days/yr
mg/day
days/yr
hours/day
cm2
Area 1
RME
Scenario*
Child 2.08
Adult 250
Child 10
(sediment)
Adult 50
(soil)
NA
NA
NA
Reference
BPJ
RAGS 1989
RAGS 1989
RAGS 1992
Area 52
RME
Scenario*
Adult 250
Adult 50
(soil)
NA
NA
NA
Beferejrtce
RAGS 1989
RAGS 1992
Area 31
Average Scenario*
Worker 50
Resident 275
(soil)
Resident 10
(sediment)
Worker 50
Resident 275
(soil)
Resident 10
(sediment)
Worker 50
Resident 10
Worker 4
Resident 1
Worker 1,980
Resident 1,900
RME Sc*»ario*
Worker 50
Resident 350
(soil)
Resident 20
(sediment)
Worker 50
Resident 350
(soil)
Resident 20
(sediment)
Worker 50
Resident 20
Worker 4
Resident 1
Worker 2,120
Resident 5,000
Refe^ence ;
BPJ
BPJ
BPJ
RAGS 1992
BPJ
BPJ
BPJ
BPJ
BPJ
BPJ
EFH 1989
EFH 1989
31620\9605.(MO\TBL-7
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0162
Final Record of Decision
Revision No.: 0
Date: 05/21/96
Page 54
Table 7 (Continued)
Exposure Parameters Used in Human Health Risk Assessment at OU 5
Exposure
Patltway
Incidental
Ingcstion of
Surface Water
Inhalation of
Soil Particulates
Ground water
Ingestion
Parameter
Exposure
Frequency
Ingestion Rate
Exposure
Frequency
Inhalation Rate
Average
Particulate
Cone. (PM10)
Exposure
Frequency
Ingestion Rate
Units
days/yr
ml/day
days/yr
m3/day
kg/m3
days/yr
I/day
Area 1
KM£
Scenario*
Child 2.98
50
NA
NA
NA
NA
NA
Reference
BPJ
BPJ
Area $2
&ME
Scenario*
NA
NA
NA
NA
NA
NA
NA
JR#&rett
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5
U.S. Na\7 CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0162
Final Record of Decision
Revision No.: 0
Date: 05/21/96
Page 55
Table 7 (Continued)
Exposure Parameters Used in Human Health Risk Assessment at OU 5
Exposure
Pathway
Dermal
Exposure to
Groundwater
While
Showering
Inhalation of
Volatiles From
Groundwater
Parameter
Exposure
Frequency
Exposure Time
Skin Surface
Area
Exposure
Frequency
Indoor
Inhalation Rate
Water to Air
Conversion
Factor (ACF)
Units
days/yr
hrs/day
cm2
days/year
rh3/day
l/m3
Area I
RME
Scenario*
NA
NA
NA
NA
NA
NA
Reference
Areat$2
RME
Scenario*
NA
NA
NA
NA
NA
NA
JRefmnce
*
Am 31
Average So&warto11!
Worker NA
Resident 275
Worker NA
Resident 0.12
Worker NA
Resident 20,000
Worker NA
Resident 275
Worker NA
Resident 15
Worker NA
Resident 0.5
RM$ Scenario*
Worker NA
Resident 350
Worker NA
Resident 0.17
Worker NA
Resident 20,000
Worker NA
Resident 350
Worker NA
Resident 15
Worker NA
Resident 0.5
Reference ;
BPJ
BPJ
EFH 1989
BPJ
EFH 1989
RAGS 1989
31620\9605.040\TBL-7
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0162
Final Record of Decision
Revision No.: 0
Date: 05/21/96
Page 56
Table 7 (Continued)
Exposure Pnnirnclcrs Used in Human Health Risk Assessment at OU 5
Exposure
Pathway
All Pathways
Parameter
Exposure
Duration
Body Weight
Averaging Time
Carcinogenic
Averaging Time
Noncarcinogenic
Units
years
kg
days
days
Area 1
RME
Scenario*
Child 6
Adult 25
Child 38.5
Adult 70
25,550
Child 2,190
Adult
9,125
Reference
EFH 1989
RAGS 1989
Anderson
1985b
RAGS 1989
RAGS 1989
RAGS 1989
Area 62
RME
Scenario*
Adult 25
Adult 70
25,550
Adult 9,125
Reference
RAGS 1989
RAGS 1989
RAGS 1989
RAGS 1989
Ar*ia 31
Average Scenario*
Worker 25
Resident 9
Adult 70
2,550
Worker 9,125
Resident 3,285
RME Scenario4
Worker 25
Resident 30
Adult 24
Child 6
Adult 70
25,550
Worker 9,125
Resident 10,950
Reference
RAGS 1989
RAGS 1989
RAGS 1989
RAGS 1989
The average scenario and the RME scenario columns show the case (e.g., worker) and the exposure parameter (e.g., 50). The units in which the
exposure parameters are expressed are shown in the third column.
bAnderson E.; N. Browne; J. Ramig; T. Warn, Development of Statistical Distributions or Ranges of Standard Factors Used in Exposure Assessments,
U.S. Environmental Protection Agency, Exposure Assessment Group, Office of Health and Environmental Assessment. 1985.
31620\9605.040\TBL-7
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 57
CTO 0162
Table 7 (Continued)
Exposure Parameters Used in Human Health Risk Assessment at OU 5
Notes:
BPJ Best professional judgment
EFH 1989 Exposure Factors Handbook USEPA 1989
RAGS 1989 US EPA Risk Assessment Guidance for Superfund, Part A. (1989), Part B (1992)
RME Reasonable maximum exposure
31620\9605.040\TBL-7
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-B-9295 Page 58
CTO 0162
7.1.3 Toxicity Assessment
A toxicity assessment was conducted for the COPCs 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
regarding the potential for chemicals to have adverse effects on exposed individuals (i.e.,
hazard identification).
Toxicity values are used to express the dose-response relationship and are developed
separately for cancer effects and noncancer effects. Toxicity values are derived from
either epidemiological or animal studies to which uncertainty factors are applied. These
uncertainty factors account for variability among individuals, as well as for the use of
animal data to predict effects on humans. The primary sources of toxicity values are
EPA's Integrated Risk Information System (IRIS) database and Health Effects
Assessment Summary Tables (HEAST). Both IRIS and HEAST were used to identify
the toxicity values used in the OU 5 risk assessment.
Toxicity values for cancer effects are referred to as cancer slope factors (CSFs). CSFs
have been developed by the EPA for estimating excess lifetime cancer risks associated
with exposure to potential cancer-causing chemicals (carcinogens). CSFs, which are
expressed in units of l/(mg/kg/day), or (mg/kg/day)"1, are multiplied by the estimated
daily intake 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
estimate represents a conservative estimate of risk calculated from the CSF. This
approach makes underestimation of the actual cancer risk highly unlikely.
Toxicity values for noncancer effects are referred to as reference doses (RfDs). RfDs,
which are expressed in units of mg/kg/day, are estimates of acceptable lifetime daily
exposures levels for humans, including sensitive individuals. Estimated intakes of COPCs
(e.g., the amount of a chemical that might be incidentally ingested from soil) are
compared with the RfD to assess risk.
Toxicity values are only available for the oral and inhalation pathways. The EPA has
not published toxicity values for dermal contact exposures and recommends using the
oral toxicity values to evaluate the dermal pathway. In calculating chemical intakes for
dermal exposures, the oral values are adjusted by an absorption factor, which corrects for
the percentage of the chemical that is absorbed through the skin (compared with direct
oral ingestion).
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-8y-U-vzvj p?ge 5°
CTO 0162
The EPA does not currently provide a toxicity value for lead because of its unique
toxicity characteristics. As an alternative to the traditional risk assessment approach, the
EPA has published recommended acceptable screening levels for lead. At the time of
the baseline risk assessment for Area 31, these levels were 500 mg/kg for soil and
15 /xg/L for drinking water. The recommended lead levels for the screening risk
assessment for Area 1 and Area 52 were 400 mg/kg for soil and 15 /*g/L for drinking
water. Lead concentrations at these sites were compared with the respective
recommended lead levels to determine risks from lead.
Petroleum hydrocarbons were detected in soil at Area 31 above the MTCA Method A
cleanup level for TPH in soil. Whereas a toxicity value for TPH is not available in IRIS
or HEAST, the EPA has developed provisional RfDs for TPH-JP-5 and TPH-gasoline.
Petroleum is a complex mixture of hydrocarbons, many of which can contribute to
detectable TPH concentrations. The provisional RfD for TPH-JP-5 was used to evaluate
potential risks at Area 31 because this would have been the most commonly used fuel at
the site.
7.1.4 Risk Characterization
A risk characterization was performed to estimate the likelihood of adverse health
effects in potentially exposed populations. The COPCs were evaluated in the risk
characterization to determine if any of the COPCs pose unacceptable risk to human
health. Those that pose unacceptable risk are considered COCs.
The risk characterization combines the information developed in the exposure
assessment and toxicity assessment to calculate risks for cancer and noncancer effects. In
the focused human health risk assessments for Area 1 and Area 52, the risk
characterization involved comparing detected concentrations of COPCs against the site-
specific RBSCs to determine if the potential for risk existed and what the general
magnitude of the risk might be. In the baseline human health risk assessment for
Area 31, the risk characterization determined quantitative risk estimates for each
chemical in each medium. Because of fundamental differences in the mechanisms
through which carcinogens and noncarcinogens act, risks were characterized separately
for cancer and noncancer effects. The discussions below explain how the results of the
risk characterization are expressed.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
^ „ , TT >..T/-/-» ^-7 ^ nr\ T^ ^>-»or
v^Uiiu act A'IVJ. i -<\j*~ . , . ^, — ^—_
CTO 0162
A/ms 1 and 52
In the focused risk assessment, the potential for significant noncancer health effects or
unacceptable lifetime cancer risks was evaluated by comparing detected concentrations
of COPCs against the site-specific RBSCs. The exposure assumptions used to develop
the site-specific RBSCs were discussed in Section 7.1.2. The target risk levels for the
site-specific RBSCs were an HQ equal to 0.1 and a carcinogenic risk of 1.0 x 10"7.
Chemicals detected at concentrations below the RBSCs were determined to pose no
significant risk. Conversely, chemicals detected at concentrations greater than the
RBSCs were assigned a potentially unacceptable risk and were considered COCs.
Area 31
In the baseline human health risk assessment, the noncancer and cancer risks were
evaluated separately. *
Noncancer Risks. The potential for adverse noncancer effects from a single chemical in
a single medium is expressed as an HQ, which is calculated by dividing the average daily
chemical intake derived from the chemical concentration in the particular medium by the
.RfD for the chemical. The RfD is a dose below which no adverse health effects are
expected to occur. An HQ less than 1.0 is considered acceptable by the EPA.
By adding the HQs for all chemicals within a medium and across all media to which a
given population may reasonably be exposed, a hazard index (HI) can be calculated.
The HI represents the combined effects of all the potential exposures that may occur for
the exposure scenario being evaluated. An HI less than 1.0 is considered acceptable by
the EPA. Chemicals that contributed significantly to an HI greater than 1.0 were
considered COCs.
Cancer Risks. The potential health risks associated with carcinogens is estimated by
calculating the increased probability of an individual developing cancer during his or her
lifetime as a result of exposure to a carcinogenic substance. Excess lifetime cancer risks
are calculated by multiplying the CSF by the daily chemical intake averaged over a
lifetime 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 estimate, an individual has a one-in-one-million chance of
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
EngineeH^g Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 61
CTO0162
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^) represents a one-in-ten-thousand chance. The EPA recommends in
the NCP a target cancer risk range of 0.000001 to 0.0001 (or 10"6 to KT*) for CERCLA
sites (40 CFR 300). Chemicals that contributed to a cancer risk greater than 1.0 x 10"5
were considered COCs.
7.1.5 Results
Areas 1 and 52
For Area 1 and Area 52, the screening level risk assessment found no potential for
significant human health risks, and no human health COCs were defined.
*
Area 31
For Area 31, the baseline risk assessment found potential human health risks. Table 8
summarizes the results of the risk assessment for each exposure scenario. This risk
assessment is based on the Phase I and Phase II environmental data, summarized in
Table 4. Analytical results from groundwater samples collected at MW31-9A were not
included in the risk assessment, because it was assumed that a drinking water well would
not be installed where there was floating petroleum product and that there would be a
clear human health risk if such a well were installed.
No cancer risks in excess of 1.0 x 10"4 were identified for any of the scenarios evaluated.
The cancer risks for all of the scenarios fell within the 10"6 to 10"4 target range of risks of
potential concern. The RME cancer risks for future residents were near the upper end
of the target risk range. Cancer risks for both current worker scenarios and the average
future resident scenario were near the lower end of the target risk range.
The potential noncancer risk for the future residential scenario at Area 31 exceeded an
HO of 1.0 for manganese in groundwater.
The reasonable maximum exposure for lead for Area 31 indicates that there is not a
significant human health risk from exposure to lead in soils or groundwater. However,
lead was detected in one sediment sample (834 mg/kg lead) and one ash sample
(544 mg/kg lead) at levels that exceed the EPA soil action level of 500 mg/kg and the
MTCA A level of 250 mg/kg. The ash sample was collected from the ash pile southwest
31620\9605.040VTEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Final Record of Decision
Revision No.: 0
Date: 05/21/96
CTO 0162
Table 8
Summary of Potential Human Health Risks and COCs at Area 31
Exposure Scenario J
RME
Cumulative
Risk
Chemicals ojf Concern
in Specific Media
Soil j tiroundwater
Current On-Site Worker
Reasonable maximum exposure— noncancer
Reasonable maximum exposure — cancer
Average exposure — noncancer
Average exposure— cancer
HI < 1.0
CR = 2.0 x 10-6
HI < 1.0
CR = 2.0 x 10-6
NA
Dioxins/furans,
PAHs
NA
Dioxins/furans,
PAHs
ME
NE
NE
NE
Future Resident
Reasonable maximum exposure — nondmcer
Reasonable maximum exposure— cancer
Average exposure — non-cancer
Average exposure—cancer
HI = 6.3
CR = 6.0 x 10-'
HI = 3.5
CR - 3.0 x 10-6
NA
Dioxins/furans,
PAHs, PCBs
NA
Dioxins/furans,
PAHs
Manganese
Dioxins/furans
Manganese
Dioxins/furans
Notes:
CR
HI
NA
NE
PAHs
PCBs
Cancer risk
Hazard index
Not applicable. No chemicals in this medium pose significant risk.
Groundwater was not evaluated as an exposure pathway under the current on-site worker
scenario.
Polycyclic aromatic hydrocarbons
Polychlorinated biphenyls
of the underground storage tank and the surface sediments from the ditch that borders
the ash pile. The samples collected in this area are the only samples found to exceed
recommended guidelines. Therefore, this area is identified as a "hot spot11 where there
may be a potential human health risk due to contact with the ash material or the ditch
surface sediments.
Also, although numeric risk estimates were not made based on samples from the
monitoring well that contained floating petroleum product, the petroleum would present
a risk if a drinking water well were installed at Area 31.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0162
Final Record of Decision
Revision No.: 0
Date: 05/21/96
Page 63
In summary, based on Phase I and Phase II data, manganese in groundwater and floating
petroleum product in Area 31 groundwater pose potentially unacceptable human health
risks if groundwater is used as a source of drinking water. Lead concentrations in an
isolated area of ash and adjacent sediment could pose potential human health risks.
Additional groundwater sampling occurred after the risk assessment was completed.
During groundwater sampling in 1995 in Area 31, five additional organic chemicals were
identified as COCs (chloroform, 1,2-dichloroethane, styrene, vinyl chloride, and
pentachlorophenol). The maximum detected groundwater concentrations for these five
chemicals are compared to the EPA Region 10 groundwater RBSCs (which are set at
10"6 carcinogenic risk) in Table 9. Three of the five chemicals significantly exceed the
RBSC, indicating that the groundwater cancer risk may be greater than l.OE-04 in the
locations of these exceedances. However, the exceedances occurred immediately
downgradient (within 50 feet) of tl^e oil/water separator and floating petroleum product
plume, where there is already a presumed risk because of the presence of floating
petroleum product.
Table 9
Maximum Detected Groundwater Concentrations (Area 31) Compared With Default
Groundwater RBSCs for Chemicals Not Included in 1992 Baseline HHRA
Chemical
Chloroform
1,2-Dichloroethane
Styrene
Vinyl chloride
Pentachlorophenol
Maxintaa* Detected
Concentration
*g/L
5
0.8
2
4
7
EPA Kegioa 10
Groiradwater RBSC
mft*
0.275
0.197
2.27
0.0282
0.00071
7.1.6 Uncertainty
The accuracy of the risk assessment depends on the quality and representativeness of the
data and assumptions that are used. The baseline risk assessment is primarily a
decisionmaking tool for use in assessing the need for remedial action. The results of a
31620\9605.040\T£XT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
CTO 0162
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 an
effort to err on the side of protection of human health.
Uncertainty Associated With Toxicity Assessment
Uncertainties associated with the toxicity assessment are the same for both the focused
and baseline risk assessments.
For carcinogens, CSFs for probable or possible human carcinogens are given the same
weight as known human carcinogens. CSFs derived from animal data are equally
weighted with those derived from human data. Uncertainties in the combined risks are
also compounded because CSFs for various chemicals do not have equal accuracy or
levels of confidence and are not based on the same severity of effect. These factors may
result in an overestimation or undferestimation of risk. Because CSFs typically
correspond to the 95UCL of the mean probability of carcinogenic response (i.e., upper-
bound estimates), CSFs are inherently overly conservative. In addition, the assumption
that any exposure to a carcinogen poses some degree of risk is unproven, and it is
possible that low levels of some carcinogens may not actually pose any risk at all.
Because chemical-specific toxicity data are limited for most carcinogenic PAH
compounds, the 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 carcinogenic PAH, this practice may overestimate risks.
For noncarcinogens, RfDs 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, an HQ greater than 1.0 for a chemical with an RfD that incorporates a high
uncertainty and was derived from data of questionable quality may be of less concern
than the same HQ for a chemical with a better-defined RfD.
A variety of chemicals were detected during the RI for which toxicity values are not
available. For example, toxicity data (RfDs) are not available for lead and only
provisional toxicity data are available for petroleum hydrocarbons; therefore, they were
excluded from the HI calculations- Their exclusion may result in an underestimation of
the noncancer risks.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 . Page to
CTO0162
Risk associated with dermal contact with soil and sediment was not evaluated for VOCs
because competition between volatilization and absorption is expected to make dermal
absorption minimal. There is moderate to high uncertainty regarding the methodology
and absorption rates used for the dermal pathway, especially for exposures to water.
Dermal absorption values used for soil and sediment are not chemical-specific but are
based on chemical class. Dermal absorption is dependent on the amount of time the
skin is in direct contact with a chemical. Therefore, an exposure parameter that
incorporates time is needed to estimate dermal intake of a chemical. However, the
method of estimating dermal absorption from soil and sediment does not consider the
duration of contact, increasing the uncertainty associated risk estimates for dermal
absorption.
Uncertainty Associated With Exposure Assessment
*
For both the screening level and baseline risk assessments, conservative approaches were
used to select potential current and future receptors and exposure pathways to be used in
calculating risks. At Area 31, current worker, recreational, and future residential
receptors were evaluated. Very little, if any, on-site worker exposure currently occurs at
Area 31, and recreational and residential exposures may never occur unless the base is
closed and the area is developed for residential use. At Area 1, a recreational (child
visitor) scenario was evaluated, and at Areas 1 and 52, an industrial worker scenario was
evaluated. In all cases, the frequency and duration of exposure that were assumed in
order to derive the site-specific RBSCs were conservative. Industrial worker exposure at
Area 1 may never occur unless the landfill is developed in the future.
Exposure point concentrations of chemicals at the site were assumed to remain constant
for the entire exposure duration. No degradation or other natural losses of chemicals
(e.g., migration or dilution) were assumed to occur. The assumption of a static chemical
concentration for the entire exposure duration introduces a conservative bias for
chemicals that undergo environmental degradation, migration, or immobilization.
In the Area 31 baseline risk assessment, many of the exposure assumptions are default
values in EPA Region 10 guidance. The RME parameters used to evaluate exposures
are intentionally conservative to ensure that site risks are not underestimated. In
recognition of this, the EPA Region 10 guidance specifies that average exposures are
also to be quantified. Exposures differed significantly between the average and RME
scenario. Most exposure parameters used in the RME scenario were overestimates,
31620\9605.CWO\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 p*ao^ ^
CTO 0162
whereas parameters for the average exposure scenario were more representative of
typical exposures.
Uncertainty Associated With Risk Characterization
In the focused risk assessment for Areas 1 and 52, the site-specific RBSCs were
compared against the maximum detected concentrations of chemicals on site. While
useful as a screening procedure to eliminate chemicals, this may overestimate any actual
exposure that would occur on a regular basis at the site.
In the baseline risk assessment for Area 31, RME and average risks were calculated.
Because the RME scenario is designed to represent the upper-bound estimate of
probable exposure and is intentionally conservative, RME risk estimates may be
overestimates. Average risks may be more realistic but are still expected to represent
conservative risk estimates for a typical receptor. Cancer and noncancer risks are
summed in the risk characterization process to estimate potential risks associated with
the simultaneous exposure to multiple chemicals. 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.
In summary, the probability that human health risks were underestimated is low, and the
likelihood that risks were overestimated is high. Estimated future risks are highly
uncertain for the following reasons: (1) future land use assumptions are hypothetical
(i.e., exposure may never occur), and (2) the magnitude of future exposure-point
concentrations is unknown.
12 ECOLOGICAL RISK ASSESSMENT
A habitat assessment and focused ecological risk assessment were conducted for Area 1.
A qualitative assessment was conducted for Area 52, and a quantitative ecological risk
assessment was conducted for Area 31. The methods used and the major conclusions of
these assessments are summarized in the following subsections.
7.2.1 Area 1
The habitat assessment and focused ecological risk assessment were performed to
evaluate the current status of the habitats in Area 1. The overall risk assessment
31620\9605.O40\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Eneineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 67
CTO 0162
methodology compared the maximum detected chemical concentrations to ecological
RBSCs and background concentrations. The three media investigated were surface soil,
surface water (in the wetlands and storm sewer), and freshwater sediment.
Methods
Habitat Assessment. Two qualitative biological surveys of the beach and intertidal zone
were performed at Area 1, the first on August 5, 1994, by URS, and the second on
May 15, 1995, by the EPA and URS. Comparison of the results of the two surveys shows
a large degree of similarity in the species observed. Because marine biologists from two
different organizations have identified essentially the same species and certainly the
same major taxonomic groups during two different surveys, it is likely that the most
abundant taxa have been cataloged. Neither survey attempted to quantify species
abundance.
*
Focused Ecological Risk Assessment. Because the ecological risk assessment was
developed at a screening level, the approach varied from the four-part procedure (data
evaluation, exposure assessment, toxicity assessment, risk characterization) found in most
quantitative assessments. The approach used for this focused risk assessment was to
compare maximum detected chemical concentrations found in Area 1 with conservative,
media-specific ecological RBSCs. Chemicals exceeding their respective RBSCs and
background concentrations were considered COCs. Ecological assessment and
measurement endpoints were not used in this approach.
RBSC Selection for Surface Water. Freshwater RBSCs were selected to be highly
protective of a wide variety of aquatic organisms. They were obtained from a number of
sources and selected according to the following hierarchy:
(1) Freshwater chronic ambient water quality criteria (AWQC) (U.S. EPA
1991)
(2) Freshwater chronic lowest-observed-effects level (LOEL) (U.S. EPA 1991)
(3) The lower of either the marine chronic AWQC or 0.2 times the freshwater
acute AWQC (U.S. EPA 1990)
(4) 0.2 times the freshwater acute LOEL (U.S. EPA 1991)
31620\9605.(MO\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract Me N621^ 8°-P 02OC Pase 68
CTO 0162
(5) The lowest chronic LOEL available from the aquatic toxicity literature
(6) 0.2 times the marine acute AWQC (U.S. EPA 1991)
(7) 0.04 times an LC50 or other lethal endpoint
RBSC Selection for Freshwater Sediment. Freshwater sediment RBSCs were selected to
be highly protective of a wide variety of aquatic organisms. RBSCs for freshwater
sediment were obtained from a variety of sources and selected according to the following
hierarchy:
(1) Effects range-low (ER-L) (Long and Morgan 1990)
(2) Marine sediment quality standards (SQS) (WAC 173-204-320)
i
(3) Equilibrium partitioning (EqP) for non-ionic organic chemicals (Di Toro
et al. 1991)
RBSC Selection for Soil. Two methods were used to determine RBSCs in soil—one for
organic compounds and one for inorganic substances. For organic compounds, a
model-based approach was used. Potential exposure was estimated by using a model for
maximally exposed surrogate vertebrate species. The species selected was the masked
shrew (Sorex cinereus), which is exposed to soil-borne chemicals through the ingestion of
soil and earthworms. That maximum dose was then compared with a conservative
toxicity value to calculate a chemical-specific RBSC. The same model-based approach
was evaluated for calculating RBSCs for inorganic substances; however, the resultant
RBSCs were 0.14 to 0.02 times the average concentrations of the respective elements in
soils of the United States. Therefore, the model-based approach was found unsuitable
and a substitute approach was employed. For inorganic substances, RBSCs were
developed by reviewing soil invertebrate and plant toxicity information. The database
comprised 108 toxicity values for 17 inorganic substances. The most conservative
published toxicity value was selected as the RBSC for inorganic substances.
Detected concentrations of inorganic chemicals were also compared with background
concentrations. Whereas a small percentage of sediments represents fluvial deposits, in
general the material sampled as sediment represents soil from the fill material placed
over the landfill and not sediments transported and reworked by fluvial processes (as
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 69
CTO 0162
would usually be the case). Background concentrations for soil were used. No
background concentrations are available for surface water.
To potentially pose an ecological concern, the chemicals must exceed both ecological
RBSCs and, where background concentrations are available, the background
concentrations.
Results
Habitat Description. Area 1 comprises three habitat types: (1) an approximately 14-acre
wetland area, characterized as a marsh or swamp, (2) a drainage ditch about 100 feet
long that drains the wetland, and (3) an approximately 6-acre upland covered landfill.
The wetland and drainage ditch have two sources: groundwater discharge and runoff
from a storm sewer draining Saratoga Street and Princeton Street along the western edge
of the base (Figure 2). The wetland usually contains saturated soil, but it may contain
surface water during the late fall and winter when precipitation is high. It is covered by
grasses and rushes. Flows in the drainage ditch are intermittent in response to
precipitation events; therefore, it is unlikely to provide habitat suitable for aquatic
species. Except when the drainage ditch carries runoff during precipitation periods, its
habitat type resembles the upland habitat of the remainder of Area 1. This area is not
considered a critical habitat for endangered species.
The upland area is covered by 3 to 4 feet of soil fill that supports introduced low-lying
grasses. Birds using the area include killdeer (observed with chicks), northern harriers
(marsh hawks), swallows, meadowlarks, and sea gulls. An eagle roost has been
cataloged about 1 mile south of Area 1 on a headland point, and eagles have been
observed at Area 1. Rabbits and a small ground mammal (probably a shrew or a mole)
have been observed at Area 1.
The beach and intertidal benthic environment below Area 1 is a high-energy
environment with no cover or topographic relief. It does not provide particularly good
habitat for most species of marine life. Most of the beach consists of cobbles covered by
sand. The approximately 10-foot-high bluff area of the landfill that exists along the
length of the beach is above the high-tide line and unavailable to marine species, except
for those that can live in the splash zone above the high-tide line. The lack of relief
means that no tide pool habitat is available at the beach below Area 1, although a few
small tide pools exist to the south of Area 1. Seven species of marine algae have been
identified in the intertidal benthic environment of Area 1. Predominant species of
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Cooiract N
CTO 0162
marine algae include sea lettuce (Ulva fenestrata), bull kelp (Nereocystis luetkeand), and
wing kelp (Alaria marginata). Twelve species of marine invertebrates have also been
observed. Predominant species of marine invertebrates include acorn barnacles (Balanus
glanduld) attached to rocky substrate, and sand fleas (Traskorchestia trastdand),
amphipods that dwell in piles of drying algae at the high-tide line.
Four bird species have been identified on the beach: killdeer (Charadrius vociferus),
glaucous-winged gulls (Laws glaucescens), Heermann's gulls (Larus heermanni), and
northwestern crows (Corvus caurinus).
Focused Ecological Risk Assessment. Table 10 presents the results of the focused
ecological risk assessment for Area 1. In soil, seven chemicals (all inorganics) were
detected at concentrations exceeding the RBSCs: cobalt, copper, cyanide, lead,
manganese, nickel, and zinc. In surface water, 10 chemicals were detected at
concentrations exceeding the RBSCs: Aroclor 1254, Aroclor 1260, cadmium, chromium,
copper, bis(2-ethylhexyl)phthalate, mercury, 2-methylnaphthalene, vanadium, and zinc.
In sediment, six chemicals, a majority of those detected, exceeded the RBSCs:
Aroclor 1254, copper, bis(2-ethylhexyl)phthalate, lead, nickel, and zinc. With the
exceptions of beryllium and selenium, all of the inorganic chemicals detected in soil
exceeded their respective background concentrations. With the exception of beryllium,
cobalt, and manganese, all of the inorganic chemicals detected in sediments exceeded
their respective background concentrations.
The Whidbey Island background concentration for manganese in soil substantially
exceeds the RBSC for sediment, whereas the maximum manganese concentration
detected in sediment at Area 1 only slightly exceeded the RBSC. Given this relatively
high background concentration, it would be likely for the concentration of manganese to
exceed the corresponding RBSC.
Five chemicals in surface water (barium, cobalt, acetone, carbon disulfide, and
4-methylphenol) and five chemicals in sediment (barium, beryllium, cobalt, vanadium,
and acetone) do not have ecological RBSCs because of a lack of toxicity information.
Therefore, potential risks may be underestimated.
Cyanide was detected twice in three groundwater samples. The concentrations were
25.8 /xg/L at MW-18 and 152.0 pcg/L at MW-103. A duplicate sample was collected from
MW-103, and cyanide was not detected at a level above the detection limit of 10 /xg/L.
The marine acute ambient water quality criterion for cyanide is 1.0 ^ug/L, suggesting a
31620\9605.CHO\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0162
Table 10
Ecological Risk-Based Screening Summary at Area 1
Final Record o Decision
Revision No.: 0
Date: 05/21/96
Page 71
Compound
Aluminum
Antimony
Arsenic
Barium
Beryllium
Cadmium
Chromium
Cobalt
Copper
Cyanide
Lead
Manganese
Mercury
Nickel
Selenium
Silver
Thallium
Vanadium
/inc
Acetone
Aldrin
&HJ
Maximum
£ott<$ttfratten
{«*%/*$
28,700
ND
12.1
147
0.51
4.20
72.5
23«2
1&
fc<8$
m
131%
ND
^&
0.360
1.50
0.650
93.8
336,0000
ND
0.0001
Wf»fdb«y
Baifcgjrobttd
{mg/*g)
17,576
8.16
7.54
98.3
0.52
0.83
43.3
17*1
*u
44+
*$>
87.000
k 30.000
190.000
NA
5.300
!«ioa
torn
NA
ll«
ND
3.20
100.0
wa
160
ND
ND
ND
41,0
110
NA
ND
$xm
Batkgrottttd
(Hlg/k«)
ND
ND
7.54
98.3
52.0
0.83
43.3
17.1
: 44A i
-
; *&* ;
681
ND
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0162
Final Record of Decision
Revision No.: 0
Date: 05/21/96
Page 72
Table 10 (Continued)
Ecological Risk-Based Screening Summary at Area 1
Compound
Aroclor 1016
Aroclor 1254
Aroclor 1260
Benzene
Benzo(a)anthracene
Benzo(b)fluoranthene
Benzo(k)fluoranthene
Benzoic acid
Benzo(g.h,i)perylene
Benzo(a)pyrene
Butyl benzyl phthalate
Carbon disulfide
alpha-Chlordane
gamma-Chlordane
Chrysene
p-Cresol (4-methylphenoI)
4,4'-DDD
4,4'-DDE
4,4'-DDT
Mawlnnim
(ntg/kg)
0.0047
0.0170
0.0260
0.0090
0.0320
0.0800
0.0640
-
0.0650
0.0540
-
-
0.00007
0.00028
0.0350
—
0.0300
0.0170
0.0110
(ittg/kfc)
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
Soft
•SI
-
-
-
-
-
-
—
ND
-
-
ND
ND
-
-
-
ND
-
-
- .
£&
0.03
0.03
0.19
.0.41
40.0
48.0
51.0
ND
51.0
48.0
ND
ND
' 0.77
0.77
35.0
ND
17.0
7.00
0.03
IS?
No
No
No
No
No
No
No
ND
No
No
ND
ND
No
No
No
ND
No
No
No
Swrfe
Maximum
ND
fc$&
&M
ND
1.00
1.00
1.00
ND
1.00
1.00
1.00
9.00
ND
ND
1.00
1.00
ND
ND
ND
;
ND
&*•»
ND
ND
ND
ND
ND
0.65
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
RBSC
ND
Y«*
ND
ND
ND
ND
ND
No
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
31620\9605.040\TBL-10
-------
NAS WH1DBEY ISLAND, OPERABLE UNIT 5
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0162
Final Record of Decision
Revision No.: 0
Date: 05/21/96
Page 73
Table 10 (Continued)
Ecological Risk-Based Screening Summary at Area 1
Compound
Di-n-butylphthalate
Diethylphthalate
Di-n-octylphthalate
Endrin
Endrin aldehyde
Endrin ketone
Ethylbenzene
bis(2-Ethylhexyl)phthalate
Fluoranthcnc
Hcptachlor
Heptachlor cpoxide
alpha-1 lexachlorocyclohcxane
Indcno(l,2,3-c,d)pyrene
Isopropylacetone
Methoxychlor
2-M ethyl naphthalene
Naphthalene
Phenanthrene
Picric acid
,il
Maximum
Concentrator
{rttfc/kg)
0.1400
ND
0.480
0.0004
0.00028
0.0013
0.0050
1.10
0.0320
0.0001
0.0013
0.0001
0.0440
0.0010
0.0017
ND
ND
0.0200
0.0031
Whidbty
BackgrtJtmd
0fr::::;:: .
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
midbey
Background
.J^fo^ .J
-
-
-
-
-
-
-
— ' .
-
-
-
-
—
-
-
-
-
—
—
Ifcceeti*
Badkgmmd
-
-
-
-
-
-
-
**" ;
-
-
-
-
—
-
-
-
-
-
—
£BSt
c*«/^>:
ND
ND
0.58
ND
ND
ND
ND
CW7
ND
NO
ND
ND
ND
ND
ND
ND
ND
ND
ND
Exeeeds
RBSC
ND
ND
No
ND
ND
ND
ND
Y«$
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
31620\9605.040\TBL-10
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0162
Final Record of Decision
Revision No.: 0
Date: 05/21/96
Page 74
Table 10 (Continued)
Ecological Risk-Based Screening Summary at Area 1
Maximum
Concentration
Wiidbey
JW9SC
Succeeds
Maximum
RBSC
RBSC
Maximum-
Pyretic
0.0540
46.0
No
1.00
60,0
No
ND
Toluene
0.0020
240
No
ND
ND
ND
ND
N )
Xylene
0.0350
8.50
No
ND
ND
ND
ND
N )
Notes:
ODD
DDE
DDT
NA
ND
RBSC
Chemical of concern
Background concentration for organics is assumed zero
Dichlorodiphenyldichloroethane
Dichlorodiphenyldichloroethene
Dichlorodiphenyltrichloroethane
Not available
Not detected
Risk-based screening concentration
31620\9605.Q40\TSL-10
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 75
CTO 0162
potential impact to intertidal organisms if exposed to concentrations found in
groundwater. However, a high-energy beach and intertidal habitat is present along the
interface of Area 1 and the strait. Cyanide is probably attenuated to a moderate degree
when moving from the inland monitoring wells to the discharge point in the intertidal
zone. In addition, cyanide released into marine waters has low persistence because it is
readily volatilized and degraded. Therefore, it is unlikely that cyanide entering Puget
Sound in groundwater from Area 1 would affect pelagic (open water) marine organisms.
The field inspection of the intertidal zone off Area 1 did not show any signs of impact to
marine life. While the field inspections were limited in scope and were not intended to
take the place of a bioassay, the field inspections provided a limited qualitative review,
which was deemed appropriate given the conditions at the site.
Groundwater discharges into the intertidal zone. The RME concentration of cyanide,
based on three samples from two locations, is 152 /xg/L. Actual concentrations of
cyanide in the intertidal zone may be much lower, as a result of dilution and
contaminant loss mechanisms. However, groundwater seeps in the intertidal zone have
not yet been analyzed for cyanide.
If cyanide concentrations in the intertidal zone exceed the ambient water quality
criterion for cyanide (1.0 /xg/L), certain sensitive intertidal species may be at risk. The
limited biological survey found that normal communities of plants and animals are
present in the Area 1 and Area 52 intertidal zone, with no apparent adverse visual
effects. Because this is a high-energy beach, the existing intertidal species are limited to
marine algae, barnacles, sand fleas, etc. If cyanide were to affect the intertidal species,
the reduced populations of intertidal species could cause other species that feed on the
intertidal species to forage for their food at other locations. Bioaccumulation of cyanide
in animals at higher trophic levels is not expected, and thus risks to higher trophic level
organisms are not quantifiable, but are expected to be minimal.
Summary and Conclusions
In soil, seven chemicals exceeded both background concentrations and ecological RBSCs:
cobalt, copper, cyanide, lead, manganese, nickel, and zinc. Concentrations of cobalt,
manganese, and nickel exceeded the RBSCs in only 1 of 14 soil samples. The 95UCL
for cobalt (14.2 mg/kg), manganese (703 mg/kg), and nickel (87.6 mg/kg) did not exceed
the ecological RBSCs (i.e., 20 mg/kg for cobalt, 1,200 mg/kg for manganese, and
170 mg/kg for nickel), suggesting that the maximum detected concentrations used in the
risk assessment were not representative of the entire 6-acre landfill. In addition,
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
<->,, ../ .,.„<- >T_ M^'M'714--9O_TVQ'>OC P.^o-e If-
CTO 0162
concentrations exceeding RBSCs were found at depths not available to mammals and
birds. For example, cobalt and manganese were detected at 5 to 6.5 feet bgs and nickel
was detected from 0 to 8 feet bgs. Therefore, cobalt, manganese, and nickel detected in
soil in Area 1 do not pose unacceptable ecological risks.
Concentrations of copper, cyanide, lead, and zinc exceeded the soil RBSCs in greater
than 10 percent of the samples collected and their 95UCLs also exceeded the RBSCs.
This evidence suggests that the aerial extent of the RBSC exceedances is of potential
ecological concern. However, because the majority of soil samples were from depths
below 2 feet, the maximum detected concentrations in soils are not representative of
actual exposures that ecological receptors might receive. Also, exceedances for these
four chemicals should be reviewed in relation to the degree of uncertainty associated
with the ecological RBSCs.
Ecological RBSCs are based on the lowest reasonable toxicity value found in the
published literature. Terrestrial ecological RBSCs for copper, lead, and zinc in soil were
based on toxicity values for plants and soil-dwelling invertebrates. The relevance of
these values at this site to higher trophic levels, such as mammals and birds, is unknown.
Plants and invertebrates have different sensitivities to chemicals than those of birds and
mammals. Therefore, it is difficult to make conclusive inferences about impacts to
components of the terrestrial ecosystem of concern (e.g., mammals and birds) using
ecological RBSCs that are based on plant and soil-dwelling invertebrate toxicity values.
The ecological RBSC for cyanide in soil was estimated using a food-chain model for the
masked shrew. This model estimates potential exposure to soilborne chemicals through
the ingestion of soil and prey (e.g., earthworms) and compares that dose to a suitable
mammalian toxicity value. The chemical concentration in earthworms is estimated using
published bioaccumulation factors (BAFs). No chemical-specific BAF was available for
cyanide. Therefore, a default BAF (3.03) that was developed for non-ionic organic
chemicals was used. Cyanide is a highly soluble ionic organic chemical that is readily
metabolized by animals. A BAF of 3.03 probably overestimates the potential for cyanide
to accumulate in earthworms. Because cyanide concentrations in soil at Area 1 only
slightly exceeded the RBSC of 0.33 mg/kg (four of eight samples exceeding the RBSC
ranged from 0.39 to 0.68 mg/kg), it is concluded that potential ecological impacts from
cyanide at Area 1 are unlikely.
Ten chemicals in surface water (Aroclor 1254, Aroclor 1260, cadmium, chromium,
copper, bis[2-ethylhexyl]phthalate, mercury, 2-methylnaphthalene, vanadium, and zinc)
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity. Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 77
CTO0162
and six chemicals in sediment (Aroclor 1254, copper, bis[2-ethylhexyl]phthalate, lead,
nickel, and zinc) exceeded background concentrations and RBSCs. The degree of
exceedance for some chemicals was more than an order of magnitude (e.g., lead in
sediment exceeded the background concentration by a factor of 45 and exceeded the
RBSC by a factor of 19), suggesting the potential for ecological impacts to specific
organisms inhabiting the small wetland. However, because the wetland is small and
surface water is not permanent, organisms contacting surface water and sediment are
limited primarily to invertebrates and plants.
7.2.2 Area 52
A focused ecological risk assessment was not performed for soil at Area 52. This area,
which consists primarily of buildings and paved areas, was not screened because of its
low value as habitat and because ttye area with the potentially contaminated media is not
available to organisms. No surface water has been reported in the area. Chemicals
detected at the site were limited to subsurface soil and groundwater. Because plants and
animals are unlikely to be exposed directly to chemicals in subsurface soil, no risks are
expected from subsurface soil contamination.
The ecological risk assessment for Area 52 groundwater was limited to the effects of
groundwater as it discharges into the marine environment. As with Area 1, the
ecological risk from groundwater at Area 52 is limited to the effects on the intertidal
marine environment as the groundwater discharges into the Strait of Juan de Fuca.
Chemicals detected in groundwater monitoring wells in Area 52 at concentrations
exceeding marine water quality criteria are not expected to exceed these criteria at the
point of discharge. The semivolatile COPCs in Area 52 groundwater (bis[2-
ethylhexyljphthalate and PAH compounds) will be subject to a high degree of retardation
as adsorption to soil occurs. Vinyl chloride concentrations in wells near MW-4 are lower
than those in MW-4 by a factor of three, demonstrating that dispersion is significant.
Further dilution from tidal effects is expected for all COPCs in groundwater. Although
free-phase petroleum hydrocarbons may be discharging into the intertidal zone, this has
not been observed. No marine water quality criteria exist for petroleum hydrocarbons.
If chemical concentrations in the intertidal zone exceed ambient water quality criteria,
certain sensitive intertidal species may be at risk. The biological survey found that
normal communities of plants and animals are present in the Area 1 and Area 52
intertidal zone, with no apparent effects from groundwater discharge. Because this is a
high-energ}7 beach, the existing intertidal species are limited to marine algae, barnacles,
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
CTO 0162
sand fleas, etc. If the chemicals in groundwater were to affect the intertidal species, the
reduced populations of intertidal species could cause other species that feed on the
intertidal species to forage for their food at other locations. Bioaccumulation of Area 52
COPCs in animals at higher trophic levels is not expected, and thus no risks are expected
to higher trophic level organisms.
7.2.3 Area 31
A focused ecological risk assessment was conducted at Area 31, according to both
federal and Washington State guidance. Area 31 is principally terrestrial, with an area of
seasonally saturated soils resulting from an area of low topography. Exposure modeling
was used to evaluate potential ecological risks.
Exposure models use results of chemical analysis, chemical biotransfer factors, and
exposure factors to provide conservative dose estimates for receptors. Estimated doses
are compared with conservative toxicity reference values (TRVs) to evaluate risk. TRVs
are available for some chemicals and media. They are not site-specific and may,
therefore, lead to erroneous conclusions.
Methods
Data Evaluation. Data describing chemical concentrations in various media were
evaluated for inclusion in the risk assessment. The environmental matrices include the
biologically active portion of the soil profile (i.e., soil from the surface down to 60 cm,
which is considered the maximum depth for root penetration, burrowing mammals, and
the majority of soil-dwelling microflora and microfauna), the surface water, and the
surface sediment (i.e., sediment from the surface down to 20 cm, which is the horizon of
greatest.biological activity). Groundwater was not considered in the ecological risk
assessment because of the lack of an exposure route.
The average and RME concentrations of chemicals were estimated by using the
arithmetic mean and the 95UCL of the arithmetic mean. When the 95UCL exceeded
the maximum detected concentration, the maximum detected concentration was used to
represent the RME concentration.
Chemical data were available from Phases I and II of the RI. All data were validated by
the analytical laboratories and by an independent contractor.
31620\9605.Q40\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Fage 79
CTO0162
COPC Selection. COPC selection in soil, surface water, and sediment was based on the
frequency of detection; the nutritional essentiality of minerals and salts; a comparison
with background concentrations; and a comparison with regulatory criteria, toxicological
guidance values, or RBSCs.
Exposure Assessment. Area 31 is principally terrestrial, with seasonally saturated soils in
areas. It is maintained void of trees and is predominantly a grass bushland. Species
known to occur in the area include Douglas fir, western hemlock, western red cedar,
grand fir, red alder, and big leaf maple. Common understory plants include salmonberry,
elderberry, salal, Oregon grape, oceanspray, snowberry, and rose. In elevated microsites,
dense patches of Scotch-broom predominate. Wildlife that may inhabit the area include
cottontail rabbit and black-tailed deer. Domestic cats originating from the residences
located east of the base are commonly observed at Area 31. No endangered, threatened,
or unique species have been observed at Area 31. In addition, it is highly unlikely that
species of concern listed for NAS Whidbey Island (i.e., bald eagle, osprey, and peregrine
falcon) will use Area 31 for an ecologically significant percentage of time because of
aircraft activity and the lack of suitable nesting habitat.
The following receptors and routes of exposure were selected for evaluation by exposure
modeling:
• Root uptake from soil by any of a variety of endemic grasses
• Soil-dwelling invertebrate (earthworm)
- Ingestion of soil
- Ingestion of vegetation
- Dermal sorption from contact with soil
• Herbivorous small mammal (Townsend's vole)
- Ingestion of vegetation
- Incidental ingestion of soil
- Insestion of surface water
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 80
CTO0162
• Herbivorous bird (California quail)
- Ingestion of vegetation
- Incidental ingestiqn of soil
- Ingestion of soil as grit
- Ingestion of surface water
• Insectivorous small mammal (masked shrew)
- Ingestion of soil invertebrates (earthworms)
- Incidental ingestion of soil
• Carnivorous mammal (long-tailed weasel)
- Incidental ingestion of soil
- Ingestion of Townsend's vole
- Ingestion of surface water
• Carnivorous bird (northern harrier)
- Ingestion of Townsend's vole
Chemical intake via each route of exposure was estimated using equations taken from
the U.S. Fish and Wildlife Service and the EPA.
Results
Hazard quotients for terrestrial receptors at Area 31 are summarized in Table 11.
Generally, an HQ exceeding 1.0 indicates some potential for adverse effects, but due to
the conservative assumptions used in the modeling, actual risks are highly uncertain for
HQs less than 10. Results of exposure modeling showed that four chemicals (lead,
2,3,7,8-tetrachlorodibenzo-p-dioxin [TCDD], N-nitrosodiphenylamine, and 2-butanone)
had RME HQs exceeding 1.0 for at least one receptor. However, risks from two of
these chemicals (N-nitrosodiphenylamine and 2-butanone) are considered highly unlikely
because RME HQs are less than 10 and the models use highly conservative input
parameters to assess risk. Ecological risks at Area 31 are therefore limited to the
masked shrew and are attributable to lead and 2,3,7,8-TCDD in surface soil.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0162
Table 11
Summary of Hazard Quotients to Terrestrial Receptors at Area 31
Final Record o) Decision
Revision No.: 0
Date: 05/21/96
Page 81
Chemical
2,3,7,8-TCDD
Lead
N-Nitrosodiphenylamine
2-Butanone
tom^ttto Vote
Average
0.326
0.997
0.251
0.736
RME
0.597
1.52
0.435
1.7
California Qoail
Average
<0.1
<0.1
NC
NC
KME
<0.1
<0.1
NC
NC
ItMfrttiMVtmti
Average
2.55
5.58
<0.1
<0.1
KME
4.67
8.49
0.119
<0.1
Northern Hanri^r
Average
<0.1
<0,1
NC
NC
8MB
<0.1
<0.1
NC
NC
Masked Shnw ;
Averag? [ RM^ :
1130
102
4.18
1,28
2070
155
7.23
2.95
Notes:
NC Not calculated
RME Reasonable maximum exposure
TCDD Tetrachlorodibenzo-p-dioxin
31620\9605.040\TBL-11
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
j7^;M^T-;nrr FipM A rtivm/ Northwest Date: 05/21/96
Coiitracl No. N62474-89-D-9295 Page 82
CTO 0162
7.2.4 Ecological Risk Assessment Summary
Area 1 and Area 52
A focused ecological risk assessment was conducted for Area 1, and a qualitative
ecological risk assessment was conducted for Area 52. In each case, results of chemical
analyses were evaluated against site-specific RBSCs developed for ecological receptors.
Ecological receptors for Area 1 were identified for soil and included a shrew for organic
chemicals and earthworms and other soil invertebrates for inorganic chemicals. To
assess ecological risk in other media at Area 1 (i.e., surface water and sediments),
RBSCs were collected or derived from literature sources. In Area 52, soil is not
expected to allow chemical exposure for ecological receptors; therefore, only
groundwater was evaluated for its effects on the intertidal environment.
*
Potential ecological risks from groundwater at Area 1 and Area 52 would be limited to
effects in the intertidal marine environment as the groundwater discharges into the Strait
of Juan de Fuca. Chemical concentrations in inland monitoring wells at Areas 1 and 52
exceeded marine water quality criteria, but it is not known whether these exceedances
occur at the point of discharge. Because the intertidal species present at Areas 1 and 52
are lower trophic level organisms such as marine algae, barnacles, and sand fleas, and
because the COPCs in groundwater do not bioaccumulate, risks to higher trophic level
organisms are expected to be minimal.
In Area 1 soil, copper, lead, and zinc showed some potential for adverse ecological
impacts. However, the toxicity values used for these chemicals are based on plant and
soil-dwelling invertebrate studies, and their relevance to higher trophic levels such as
mammals and birds at this site is unknown. Also, because the majority of soil samples
were from the landfill contents, the maximum detected concentrations in soils are not
representative of actual exposures that ecological receptors might receive. Chemicals
exceeding ecological RBSCs in Area 1 surface water include Aroclor 1254 and Aroclor
1260, cadmium, chromium, copper, bis(2-ethylhexyl)phthalate, mercury,
2-methylnaphthalene, vanadium, and zinc. Chemicals exceeding ecological RBSCs in
Area 1 sediments include Aroclor 1254, copper, bis(2-ethylhexyl)phthalate, lead, nickel,
and zinc. Although many chemicals in both surface water and sediments exceeded the
RBSCs—and in some cases by relatively large magnitudes—the small size of the wetland
and the impermanence of the surface water should limit ecological risk.
3I620\9605.O40\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Encrineenng Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 rage &:>
CTO 0162
Area 31
Although exposure modeling indicated potential adverse impacts to the masked shrew
attributable to 2,3,7,8-TCDD and lead, potential risks to the shrew from the 2,3,7,8-.
TCDD are considered highly uncertain due to the limited current knowledge of its
toxicity. No risks were identified to birds or carnivorous animals.
7.3 SUMMARY OF SITE RISKS
At Areas 1 and 52, no potential for significant human health risks were found and no
human health COCs were defined. Some potential ecological risk was found in the
marine water next to and originating from the sites. At Area 31, there was limited
human health risk from contaminated soils and a human health risk in the groundwater.
There was limited ecological risk at Area 31.
Actual or threatened releases from Areas 1, 52, and 31, if not addressed by
implementing the response action selected in this ROD, may present an imminent and
substantial eridangerment to human health and the environment.
8.0 REMEDIAL ACTION OBJECTIVES
This section explains the basis for remedial action at OU 5, 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.
8.1 AREA 1
8.1.1 Need for Remedial Action
The human health risk assessment evaluated the exposure of future recreational visitors
to chemicals in soil surface water, and sediments and exposure of industrial workers to
chemicals in soil a: Area 1. Exposure to chemicals in groundwater was not evaluated
because groundwaier is not a potential source of drinking water. As discussed in
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest . Date: 05/21/96
Contract No. N62474-89-C-?2?r P^rrp 84
CTO 0162
Section 7.1.5, the estimated human health risks were below the screening levels for all of
the exposure scenarios at Area 1. Because the human health risk assessment determined
that there are no current or potential future human health risks at Area 1, no actions are
needed to protect human health.
The following subsections discuss the need for remedial action as determined by the
results of the ecological risk assessment and consideration of ARARs for soil, surface
water, sediments, and groundwater at Area 1. Specific RAOs are presented for each
medium.
Soil
The ecological risk assessment indicated some potential for adverse impacts to birds and
mammals attributable to three COCs (copper, lead, and zinc) in Area 1 soils. However,
there was a high degree of uncertainty associated with the potential ecological risks.
One COC (gasoline-range petroleum hydrocarbons), whose concentration in soil exceeds
state cleanup levels, has been identified in subsurface soils.
Remedial action objectives were not developed for Area 1 soils because the soils did not
pose current or potential future human health risks exceeding the CERCLA risk range,
and no clear ecological risk was present.
Surface Water (Fresh Water)
The ecological risk assessment indicated no significant potential for adverse impacts to
aquatic animals attributable to Area 1 surface water. Several COCs (lead, mercury, zinc,
Aroclor 1254, Aroclor 1260, and diesel-range petroleum hydrocarbons) have been
identified whose concentrations in surface water exceed regulatory criteria. However, no
COCs exceed regulatory criteria in surface water from the drainage downgradient of the
wetland in the middle of the Area 1 landfill. As discussed in Section 6, the source of
these chemicals appears to be upgradient stormwater drainage, and the wetland functions
to remove these chemicals from surface water before its discharge to the marine
environment.
Because no risks are associated with these chemicals and the wetland naturally removes
these chemicals from surface water, no RAOs have been developed for Area 1 surface
water.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Fnmneerine Field Activity. Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 85
CTO 0162
Freshwater Sediments
The ecological risk assessment indicated no significant potential for adverse impacts to
birds and mammals attributable to Area 1 sediments. COCs (lead and Aroclor 1254)
have been identified whose concentrations in sediments exceed state soil cleanup levels.
Because no freshwater sediment cleanup levels were available, the MTCA Method B soil
cleanup levels were used in the RI for comparison purposes only.
Remedial action objectives were not developed for Area 1 sediments because the
sediments did not pose current or potential future human health risks exceeding the
CERCLA risk range, and no clear ecological risk was present.
Groundwater
>
Drinking water is not considered the highest beneficial use for groundwater at Area 1
under Washington State regulations. Therefore, no human health or ecological risks
associated with Area 1 groundwater were defined in the human health and ecological
risk assessments because groundwater was not considered as a potential source of
exposure.
In the absence of future drinking water potential, MTCA allows groundwater cleanup
levels that are based on protecting beneficial uses of adjacent surface water. MTCA
requires that groundwater entering surface waters not exceed surface water cleanup
levels at the point of entry or at any downstream location where it is reasonable to
believe that hazardous substances may accumulate (WAC 173-340-720[c][iii]). According
to this approach, four COCs (cyanide, zinc, 1,1-dichloroethene, and bis[2-
ethylhexyljphthalate) have been identified whose concentrations in groundwater exceed
marine ambient water quality criteria or other regulatory criteria for surface water.
Dilution of groundwater occurs prior to discharge to the Strait of Juan de Fuca, and
these exceedances in monitoring wells may not indicate actual exceedances at the point
of entry into the marine environment.
Cyanide is the chemical of greatest concern in Area 1 groundwater, due to the
magnitude of its exceedance of marine water quality standards and the potential for
ecological risks in the intertidal zone that this large exceedance implies. However,
cyanide concentrations were not measured in the intertidal wells because of funding and
schedule concerns, so the actual concentrations of cyanide at the point where
groundwater discharges to the intertidal zone are not known. Any effects of cyanide
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
-^ . -, -< ^-T
«ouiiUact i^
CTO 0162
would be limited to organisms in the intertidal zone, such as barnacles and sand fleas.
A biological survey of the intertidal zone revealed normal communities of plants and
animals, with no apparent ill effects from groundwater discharge. Cyanide does not
bioaccumulate in animals and is not expected to pose risks to birds or marine animals.
Based on this evidence, the Navy is assuming that cyanide in groundwater does not
present significant ecological risk. Further sampling at the point where groundwater
discharges to the intertidal zone is needed to confirm this assumption.
To address potential adverse impacts to marine life associated with these chemicals in
groundwater, the following RAO has been developed for Area 1 groundwater:
• Confirm protection of ecological receptors in the marine environment by
determining compliance with the water quality standards for marine surface
waters at the point of groundwater discharge
t
8.1.2 Remedial Goals
The RAO for groundwater defined in the previous section includes evaluating potential
ecological risks and complying with chemical-specific ARARs. Chemical-specific ARARs
for Area 1 groundwater that correspond with the RAO are presented in Table 12. The
most stringent of these criteria will be used to evaluate groundwater quality at the point
of discharge and assess the protection of ecological receptors in the marine environment.
8.2 AREA 52
8.2.1 Need for Remedial Action
The human health risk assessment evaluated the exposure of future industrial workers to
chemicals in subsurface soil at Area 52. The current industrial worker exposure was not
evaluated because no COCs were found in surface soil at Area 52. Exposure to
groundwater was not evaluated because groundwater is not a potential source of drinking
water. As discussed in Section 7.1.5, the estimated human health risks were below the
CERCLA target levels for all of the exposure scenarios at Area 52. Thus, the human
health risk assessment did not demonstrate a need to take remedial action at Area 52 to
protect human health. The following subsections discuss the need for remedial action as
determined by the results of the ecological risk assessment. Specific RAOs are
presented for each medium.
31620\9605.(MO\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5
U.S. Navy CLEAN Contract
Engineering Field Activity. Northwest
Contract No. N62474-89-D-9295
CTO 0162
Final Record of Decision
Revision No.: 0
Date: 05/21/96
i age & /
Table 12
Chemical-Specific ARARs for Area 1 Groundwater
Chemical
Cyanide
Zinc (dissolved)
1,1-Dichloroethene
bis(2-Ethylhexyl)
phthalate
M&aofl&i
Detected
C^Bcentratioo
Ifgft*
152
146
5
90
Background '
Concentration
frg/**) :
0
56
0
0
C^raic^-Spedfic ARAKs Q*g/L> ;
Washington
Marine
WQS*
lc
76.6d
NA
NA
Federal ;
Marine
WQC'
r
86d
224,000C'C
NA
M3K&
Method B
(Sur&ce
Wafcsr)*
51,900
16,500
1.93
3.56
Selected
Cleanup
Level
1
76.6
1.93
3.56
aBased on protection of aquatic life.
bMTCA Method B groundwater cleanup level is based on protection of human health from human
consumption of organisms from adjacent surface water.
Teased on acute exposure.
dBased on chronic exposure.
'To-be-considered (TBC) value based on lowest-observed-effects level.
Notes:
MTCA Model Toxics Control Act
NA No available value
WQS Water quality standard
Soil
The ecological risk assessment concluded that no ecological risks were expected at
Area 52. One COC (diesel-range petroleum hydrocarbons) has been identified whose
concentrations in subsurface soil exceed state cleanup levels.
Remedial action objectives were not developed to address the exceedances of a
chemical-specific ARAR because soils at Area 52 did not pose current or potential
future human health risks exceeding the CERCLA risk range, and no clear ecological
risk was present.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Co^Lr^Cc Mo. MC2--*7*-C2 D 92^c Pa<^° ££
CTO 0162
Groundwater
Drinking water is not the highest beneficial use for groundwater at Area 52 under
Washington State regulations. Therefore, no human health or ecological risks associated
with Area 52 groundwater were defined in the human health and ecological risk
assessments because groundwater was not considered as a potential source of exposure.
However, floating petroleum product is present and COCs have been identified (vinyl
chloride, bis[2-ethylhexyl]phthalate, carcinogenic PAHs [cPAHs], and petroleum
hydrocarbons) whose concentrations in Area 52 groundwater exceed marine ambient
water quality criteria or other regulatory criteria. The thickness of the floating
petroleum product plume is diminishing over time, and the plume appears to be
breaking up. While petroleum product was not detected in the intertidal sandpoint
monitoring wells, dissolved petroleum constituents were found at concentrations below
regulatory levels. This indicates that petroleum constituents are migrating toward the
marine surface water, but at concentrations below regulatory levels.
Dilution of chemicals in groundwater occurs prior to discharge to the Strait of Juan de
Fuca, and exceedances of regulatory criteria in inland monitoring wells may not indicate
actual exceedances at the point of entry into the marine environment. To address
potential adverse impacts to marine life associated with these chemicals in groundwater,
the following RAOs have been developed for Area 52 groundwater:
• Prevent the migration of floating petroleum product from groundwater to
marine surface water
• Confirm protection of ecological receptors in the marine environment by
determining compliance with the water quality standards for marine surface
waters at the point of groundwater discharge
8.2.2 Remedial Goals
The RAOs for groundwater defined in the previous section include reducing potential
ecological risks and complying with chemical-specific ARARs. Chemical-specific ARARs
for Area 52 groundwater that correspond with the RAO are presented in Table 13.
These criteria will be used to evaluate groundwater quality at the point of discharge,
evaluate the effectiveness of the selected remedy, and assess the protection of ecological
receptors in the marine environment.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0162
Final Record of Decision
Revision No.: 0
Date: 05/21/96
Table 13
Chemical-Specific ARARs for Area 52 Groundwater
Chemical
Vinyl chloride
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Chrysene
Indeno(l,2,3-cd)pyrene
TPH
Maxiimmt Detected
Concentration
fr*/D
63
0.04
0.07
0.05
0.05
0.04
36,000
CheraicaJ-Specific ARARs
NA
NA
NA
NA
NA
NA
NA
tttta !
JMfeMB \
Cleanup i
LmF I
2.92
0.02%
0.0296
0.0296
0.0296
0.02%
l,000b
aMTCA Method B groundwater cleanup level is based on protection of adjacent surface water.
bMTCA Method A groundwater cleanup level.
Notes:
MTCA Model Toxics Control Act
NA No criteria promulgated
TPH Total petroleum hydrocarbons
8.3 AREA 31
8.3.1 Need for Remedial Action
The human health risk assessment evaluated the exposure of current on-site workers and
future residents to chemicals in soil, ditch sediments, and groundwater at Area 31.
Groundwater was evaluated as a potential future source of drinking water because the
shallow aquifer at Area 31 is a potential source of drinking water under Washington
State regulations. As discussed in Section 7.1.5, the estimated human health risks were
below the CERCLA target levels for all of the exposure scenarios at Area 31, with the
exception of potential'noncancer risks due to manganese in groundwater under the
31620\9605.WO\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-8°-D-0?0^ P?rrp on
CTO 0162
future residential scenario. Also, the risk assessment assumed that groundwater from a
well containing floating petroleum product would not be used as a source of drinking
water, because this would present a clear risk to human health. Thus, although numeric
risk estimates were not made based on samples from the monitoring well that contained
floating petroleum product, the petroleum would present a risk if a drinking water well
were installed at Area 31. Currently, groundwater at Area 31 is not used for drinking
water. Thus, remedial actions designed to prevent potential human health risks from
manganese and petroleum in groundwater were considered. The following subsections
discuss the need for remedial action as determined by the results of the human health
and ecological risk assessments and consideration of ARARs for soil, ditch sediments,
and groundwater at Area 31. Specific RAOs are presented for each medium.
Soil, Ditch Sediment, and Ash
The baseline human health risk assessment estimated that current and future risks due to
chemicals in soil in Area 31 were within the acceptable CERCLA risk range, with the
exception of lead. Lead concentrations in an isolated area of ash and adjacent ditch
surface sediment could pose a potential human health risk.
The ecological risk assessment evaluated ecological risks due to chemicals in surface soil.
Subsurface soil (below 2 feet) was not evaluated because organisms at Area 31 are not
likely to be exposed to that medium. Ash was not evaluated because it was assumed to
be scheduled for a remedial action and therefore would not pose a risk to ecological
receptors. The ecological risk assessment indicated the potential for adverse ecological
effects because of COCs in the upper 2 feet of Area 31 surface soil. Lead and dioxin
were identified in surface soil as COCs that may cause potential adverse effects to the
masked shrew. No significant ecological risks were identified for other mammals, raptors
(e.g., hawks and owls), or herbivorous birds. The ecological risk assessment concluded
that potential risks to the shrew are highly uncertain; therefore, RAOs based on
protecting the masked shrew were not developed.
Exceedances of chemical-specific ARARs (MTCA cleanup levels) were identified for
beryllium, lead, Aroclor 1260, dioxins, indeno(l,2,3-cd)pyrene, and petroleum
hydrocarbons in soil at Area 31. Lead also exceeded the MTCA cleanup level in one
ash sample and in one ditch sediment sample. Because the ditch sediments are
vegetated and are relatively immobile, no remedial action objectives were developed to
address the one lead exceedance in sediments. Beryllium is widely distributed in surface
and subsurface soil at Area 31. The maximum concentration of 0.88 mg/kg is only 1.7
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Eneineerine Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 91
CTO 0162
times the background concentration of 0.52 mg/kg. Because the concentration is not
significantly above background, beryllium is not considered a target chemical for
remediation.
Remedial action objectives were not developed to address these exceedances of
chemical-specific ARARs because soils at Area 31 did not pose current or potential
future human health risks exceeding the CERCLA risk range, and potential ecological
risks were uncertain and limited to the masked shrew. However, petroleum
hydrocarbons found in subsurface soils near the oil/water separator are a source of
groundwater contamination. To address this impact to groundwater quality, the
following RAO was developed for Area 31 soil:
* Reduce the sources of petroleum hydrocarbons in subsurface soils that may
cause groundwater contamination in excess of state cleanup levels for
petroleum hydrocarbons
To address potential human health risks due to lead in ash, the following RAO was
developed:
• Prevent human exposure to lead in ash
Groundwater
The primary concern with Area 31 groundwater is the presence of floating petroleum
product on the groundwater near the oil/water separator, which would pose an
unacceptable human health risk if a drinking water well were installed in the area of the
floating petroleum product and immediately downgradient (within about 50 feet). The
floating petroleum product is acting as an ongoing source of dissolved COCs that could
potentially spread in groundwater.
The baseline risk assessment estimated that current human health risks were within the
acceptable CERCLA risk range for Area 31 groundwater. Under the future residential
scenario, which assumes the use of groundwater as a source of drinking water,
unacceptable human health risks would exist in the area of the floating petroleum
product. Manganese in groundwater would pose an unacceptable noncancer risk.
Groundwater was not considered a medium of potential concern for ecological risk.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Cx^:.^ !^. r:£2--7---C?--!?-92?5 Page 92
CTO 0162
Exceedances of chemical-specific ARARs were identified for several chemicals-detected
in groundwater at Area 31, as shown in Tables 4 and 5. These COCs include petroleum
hydrocarbons, dioxins and furans, VOCs, SVOCs, inorganics, and PCBs (Aroclor 1260).
Concentrations of manganese in groundwater may be elevated as a result of reducing
conditions associated with microbial degradation of petroleum. Remediation of the
petroleum constituents may shift the nature of the groundwater to oxidizing conditions,
causing the manganese to precipitate out of the groundwater. The remainder of the
COCs are associated with floating petroleum product near the oil/water separator or the
UST.
To address the possible future human health risk and exceedances of ARARs associated
with these chemicals, and to prevent the potential spreading of contamination in
groundwater, the following RAOs were developed for Area 31 groundwater:
t
« Prevent the migration of floating petroleum product and dissolved COCs
that are present above ARARs in groundwater
• Prevent human exposure under the future residential scenario to the COCs
in groundwater that are present at concentrations above state and federal
cleanup levels
8.3.2 Remedial Goals
The RAOs for soil and groundwater defined in the previous section include reducing
potential future human health risks and complying with chemical-specific ARARs.
For Area 31 soil, numeric chemical-specific cleanup levels were not developed. The
RAO for soil is based on reducing or eliminating impacts to groundwater quality. The
effectiveness of the remedy in achieving the soil RAO will therefore be evaluated based
on the results of groundwater monitoring.
For Area 31 groundwater, chemical-specific cleanup levels that correspond with the
RAOs are presented in Table 14. The effectiveness of the remedy in achieving the
groundwater RAOs will be evaluated primarily with regard to preventing the spread of
COCs at concentrations above these cleanup levels. Exceedances of the groundwater
cleanup levels in some wells may persist on site for some time and would be addressed
through institutional controls to prevent groundwater use.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0162
Final Record of Decision
Revision No.: 0
Date: 05/21/96
rage yj
Table 14
Chemical-Specific ARARs for Area 31 Groundwater
Chemical
Beryllium
Lead
Manganese
Mercury
Aroclor 1260
Benzene
Naphthalene
Pentachlorophenol
Styrene
Toluene
Vinyl chloride
2,3,7,8-TCDD (TEC)
TPH
Maximum
CoacentratioDi
&S/t)
0.29
198
3,780
3.6
0.70
380
900
7
2
3,200
4
5.3 x 10-3
230,000
Background
Oancefltration
•frtfp •
NC
9.7
125
0.3
0
0
0
0
0
0
0
0
0
Cbe*aicai*Specific ARAfts (pg/X>)
Federal
MCL i
4
15
2
0.5
5
1
100
1,000
2
30 x 10'6
State
MCL
50
2
5
2
MTCA
Method 8
for Grouadwater
0.0203
5a
80
4.8
0.011
5
320
1
1.46
1,600
0.023
0.58 x 10-6
1,000*
S*fe£ted
Cleanup
Lev*!
0.0203
9.7
125
2.0
lb
5
320
1
1.46
1,000
O.lb
0.58 x 10'6
1,000
aMTCA Method A groundwater cleanup level.
bBased on practical quantitation limit obtained from "Guidance on Sampling and Data Analysis
Methods," January 1995 (Ecology Publication 94-49).
Notes:
MCL Maximum contaminant level
MTCA Model Toxics Control Act
NC Not calculated because this analyte was not detected in background samples
TCDD Tetrachlorodibenzo-p-dioxin
TEC Toxicity equivalent concentration (individual dioxins/furans concentrations were converted to
equivalent 2,3.7,8-TCDD concentrations using EPA's toxicity equivalency factors)
TPH Total petroleum hydrocarbons
3I620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N6247^-8°-in>-O9<:^ Pa
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract INO, iNoz^7^-6^-D-v2v5 ?age 95
CTO0162
marine environment would be further assessed through a groundwater monitoring
program. This alternative includes three components: deed restrictions, environmental
monitoring, and periodic reviews of environmental data. These components are
discussed in the following paragraphs.
To prevent residential development or the installation of drinking water wells, land-use
restrictions will be entered into the installation restoration site database that is part of
the NAS Whidbey Island planning and management model. These restrictions would
include special requirements for any other construction activity that may disturb
contaminated soil, including health and safety plans, environmental protection plans, and
waste management plans. In the event of property transfer, restrictive covenants on the
property would be recorded with the Island County register of deeds. The covenants
would be binding on the owner's successors and assignees, would place limiting
conditions on property conveyance, would prohibit well construction except for
monitoring purposes, and would restrict land use and construction activity that would
disturb the landfill. These restrictions would apply to the landfill plus an appropriate
buffer zone. Covenants would also require notice to environmental regulatory agencies
(e.g., the EPA, Ecology, or their designees) of any intent to transfer interest, modify its
land use, or implement construction activity; agency approvals would be required for
such actions.
Continued use of existing security measures would control physical access to Area 1 by
the general public.
An environmental monitoring program would include groundwater sampling and
biological surveys of the beach. In the 1st year, the two inland monitoring wells (MW-18
and MW-103) will be resampled one time for cyanide, and up to six intertidal
groundwater samples would be collected from seeps along the shoreline. The intertidal
groundwater seep samples would be analyzed for total and dissolved inorganics, cyanide,
VOCs, and SVOCs to determine compliance with surface water cleanup levels. If the
results of the intenidal groundwater sampling indicate compliance with surface water
cleanup levels, the sampling would be terminated.
If the results of the 1st year intertidal groundwater sampling indicate that surface water
cleanup levels are not met in the intertidal groundwater seep samples, the following
monitoring program would be instituted: A biological survey of the intertidal zone
would be conducted in the 2nd year. Up to six intertidal groundwater samples would be
collected annually from seeps along the shoreline, beginning in the 2nd year. The
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
CuuUact Nw. NG2<7^89 -D9295 Paee 96
CTO 0162
intertidal seep samples would be analyzed for total and dissolved inorganics, cyanide,
VOCs, and SVOCs to determine compliance with surface water cleanup levels in the first
year. After the 1st year of monitoring, the Navy and the EPA would consider limiting
the chemical analyses in subsequent years to those chemicals detected during the 1st
year. If the results of the intertidal groundwater seep sampling indicate compliance with
surface water cleanup levels for 2 consecutive years, the annual sampling would be
terminated. If compliance with surface water cleanup levels has not been attained for 2
consecutive years by the 5th year, a second biological survey of the intertidal zone would
be conducted.
Included in the monitoring program would be visual inspections of the physical condition
of the landfill bluff conducted annually for the first 5 years, and the results documented.
Because this alternative would result in some remaining exceedances of cleanup levels in
soils and potentially in groundwater, a periodic review of the environmental data would
be required no less frequently than every 5 years. The environmental data will be used
by the EPA and Navy to jointly assess the protection of ecological receptors in the
marine environment.
Estimated costs for Alternative 2 are the following, assuming 5 years of operation and a
5 percent discount factor:
Capital cost: $25,000
Present value O&M costs: $109,000
Total present worth: $134,000
9.1.3 Alternative 3—MFS Cap and Installation of Seawall
Alternative 3 consists of placing a minimum functional standards (MFS) cap over the
surface of the Area 1 landfill. An MFS cap is the standard cap required for the closure
of solid waste landfills. Alternative 3 also includes construction of an approximately
1,100-foot-long seawall along the shoreline of the Area 1 landfill to prevent erosion.
The western edge of the landfill along the shoreline would be regraded as necessary for
the construction of the seawall. Landfill material removed during the regrading would
be consolidated elsewhere within the landfill boundaries. A seawall would be
constructed from oversized riprap, extending approximately 1,100 feet along the
shoreline. The precise length and configuration of the seawall would be determined,
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
TRnprtneerin^ Field Activity. Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 rage 57
CTO 0162
after surveying, in the remedial design. The seawall would reduce the potential for
landfill erosion into the Strait of Juan de Fuca during storm events and would protect
the landfill cap.
The MFS cap would be placed over the identified extent of the landfill (approximately
330,000 square feet). The proposed design of the MFS cap, intended to comply with the
requirements of WAC 173-304, is presented below:
1. The landfill surface would be extensively regraded to facilitate drainage.
Because of design requirements, the wetlands would necessarily be filled
and covered by the cap. An average 6-inch-thick aggregate leveling base
would be placed on top of the regraded landfill surface.
2. A geosynthetic clay liner would be installed on the top surface of the
aggregate leveling base.
3. The third layer from the top would be an impermeable flexible membrane
layer composed of a 60-mil high-density polyethylene sheet,
4. The second layer from the top would be a synthetic drainage layer that is a
net-like product of two overlapping polyethylene strands covered with a
geotextile fabric on both sides.
5. The top layer would consist of a 2-foot-thick soil layer conducive to
sustaining vegetative growth. The top of the vegetative soil layer would be
fertilized and seeded with native vegetation.
6. The existing 24-inch storm drain outfall that currently feeds the wetland in
the middle of the Area 1 landfill would be re-routed directly to the Strait
of Juan de Fuca.
The MFS-type cap would eliminate the potential risk associated with COCs in soils and
sediments by preventing the exposure of human and ecological receptors to existing soils
and sediments. By preventing percolation of precipitation through vadose-zone soils, the
potential for transport of soil contaminants to groundwater may be reduced. However, it
is not certain that this percolation is causing significant groundwater contamination.
Further, under this alternative, the wetlands at Area 1 would be destroyed, and surface
water runoff from the storm drain would discharge directly to the marine environment.
31620\9605.G40\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
^ .-....,„/ M - ^rr^/fT/f OO ir> r»"vo.r Porr^ OQ
v_.wJULiU^L ASU. - \O«-'T •/-. -O^-^ - - —_ r/^i~ '
CTO 0162
Groundwater monitoring, deed restrictions, and periodic reviews would be implemented
as described for Alternative 2.
Estimated costs for Alternative 3 are the following, assuming 5 years of operation and a
5 percent discount factor:
Capital cost: $2,060,000
Present value O&M costs: $131,000
Total present worth: $2,191,000
92 AREA 52
Two remedial alternatives have been considered for Area 52.
*
9.2.1 Alternative 1—No Action
The no-action alternative was included in the range of alternatives evaluated in the
feasibility study, as required by the NCP. 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-oriented alternatives.
Costs for Alternative 1 are the following:
Capital cost: $0
Present value O&M costs: $0
Total present worth: $0
9.2.2 Alternative 2—Oil Skimming
Alternative 2 would use institutional controls to limit human exposure to petroleum
hydrocarbons present in subsurface soils and groundwater.. In addition, to prevent
migration of petroleum to adjacent surface water, floating petroleum product would be
removed from the water table surface by skimming devices. The marine environment
would be monitored for ecological effects, and groundwater seeps would be monitored
for petroleum hydrocarbons and other COCs. The thickness of the floating petroleum
product plume would-be monitored to evaluate the effectiveness of the skimming.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 JPage yy
CTO0162
The removal of floating petroleum product at Area 52 can be accomplished via two
general approaches: (1) using extraction wells to pump water and floating petroleum
product, creating cones of depression that draw floating petroleum product toward the
extraction wells, or (2) using skimming devices to remove floating petroleum product
while extracting little or no groundwater. The results of the treatability study at Area 52
have indicated that pumping rates in excess of 25 to 50 gallons per minute per extraction
well would be required to create sufficient cones of depression to draw floating
petroleum product toward the extraction wells. Furthermore, because the plume has
migrated, additional extraction wells would be required. Saltwater intrusion would likely
result from the high pumping rates. Treatment of the extracted, high-salinity water could
not be accomplished in a publicly owned treatment works or the Navy treatment works.
Discharge of this extracted water directly to marine waters would be required and may
be difficult to implement on a regulatory basis. Therefore, the second approach
(skimming devices) is considered the most technically feasible technology type.
The results of the treatability study and ongoing monitoring at Area 52 have indicated
that the floating petroleum product is continually migrating, is apparently heterogeneous
in its extent (i.e., isocontour lines are difficult to draw), and may vary in extent from wet
season to dry season. Therefore, the removal system design should be regarded as a
conceptual design that may be modified significantly in the remedial design based on
further monitoring of the floating petroleum product. The proposed configuration of the
floating petroleum product removal system is described below.
The existing monitoring wells that are screened across the water table surface would be
used as collection points for removal of floating petroleum product. Up to five
additional monitoring/collection wells would be installed and screened across the water
table surface. The locations of the additional wells would be chosen to provide
additional coverage near the Jet Engine Test Cell and downgradient, where the plume is
expected to migrate. The exact number and locations of the wells would be determined
in the remedial design. The wells would be designed to operate with skimming devices
that collect floating petroleum product and prevent the collection of groundwater.
Collected petroleum would be emptied into approved containers and sent off site for
recycling and/or disposal. The oil skimming wells would be operated until it becomes
impractical to recover significant amounts of oil. It is estimated that the skimming would
be completed in less than 5 years.
Because this configuration relies on the natural movement of the floating petroleum
product plume toward the collection wells, the remediation is expected to take several
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
ConU-acl N_ N62474-89-D-9295 Page 100
CTO 0162 .
years. This timeframe would also allow natural recovery of subsurface soils behind the
floating petroleum product plume.
The 6-inch-diameter drywell at Area 52 would be excavated to prevent possible
unauthorized disposal in the future. The excavation would be backfilled with borrow
soils. No confirmation sampling would be conducted for the drywell removal. To
prevent residential development or the installation of drinking water wells, land-use
restrictions will be entered into the installation restoration site database that is part of
the NAS Whidbey Island planning and management model. These restrictions would
include special requirements for any other construction activity that may disturb
contaminated soil, including health and safety plans, environmental protection plans, and
waste management plans. In the event of property transfer, restrictive covenants on the
property would be recorded with the Island County register of deeds. The covenants
would be binding on the owner's successors and assignees, would place limiting
conditions on property conveyance, would prohibit well construction except for
monitoring purposes, and would restrict land use and construction activity that would
disturb the site. These restrictions would apply to the site plus an appropriate buffer
zone. Restrictions on construction activities that may disturb subsurface soils may be
required only for a limited period (e.g., 10 to 30 years) until natural recovery reduces
concentrations of petroleum hydrocarbons below remedial goals. Covenants would also
require notice to environmental regulatory agencies (e.g., the EPA, Ecology, or their
designees) of any intent to transfer interest, modify its land use, or implement
construction activity; and agency approvals would be required for such actions.
A quarterly monitoring program would be implemented to monitor the thickness of the
floating petroleum product to determine the movement. The measurements of floating
petroleum product would be timed to coincide with high and low seasonal water levels.
An environmental monitoring program would include intertidal groundwater seep
sampling and biological surveys of the beach. Intertidal groundwater seep samples would
be collected biannually, in years 1, 3, and 5 following ROD signature. In each sampling
event, up to six intertidal groundwater samples would be collected from seeps along the
shoreline and analyzed for VOCs, SVOCs, and TPH to determine compliance with
surface water cleanup levels. After the 1st year of monitoring, the Navy and the EPA
would consider limiting chemical analyses in subsequent years to those chemicals
detected during the 1st year. The surface water cleanup levels are shown in Table 13.
The point of compliance for attaining these cleanup levels is in the seeps along the
shoreline. Biological surveys of the intertidal zone would be conducted in years 2 and 5
following; ROD signature.
31620\9605.040\TEXT
-------
HAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 101
CTO 0162
Because this alternative would result in some remaining exceedances of cleanup levels
in soils, a periodic review of the environmental data would be required no less frequently
than every 5 years. The environmental data will be used to evaluate the effectiveness of
the remedy and assess the protection of ecological receptors in the marine environment.
Estimated costs for Alternative 2 are the following, assuming 5 years of operation and a
5 percent discount factor:
Capital costs: $54,000
Present value O&M costs: $159,000
Total present worth: $213,000
9.3 AREA 31
Four remedial alternatives have been considered for Area 31.
9.3.1 Alternative 1—No Action
The no-action alternative was included in the range of alternatives evaluated in the
feasibility study, as required by the NCP. 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-oriented alternatives.
Costs for Alternative 1 are the following:
Capital cost: $0
Present value O&M costs: $0
Total present worth: $0
9.3.2 Alternative 2—Oil Skimming
Alternative 2 would use institutional controls to limit exposure to COCs in surface and
subsurface soils and to prevent exposure to COCs in groundwater. The oil/water
separator tank would be excavated and removed for off-site disposal. In addition, to
prevent further migration of petroleum and related chemicals in groundwater, oil
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Cv^-ic^i. ICw. IIC,2~~'. C? D ?2?5 Pape 1.02
CTO 0162
skimming wells would be installed around the oil/water separator to remove floating
petroleum product.
To prevent residential development or the installation of drinking water wells, land-use
restrictions will be entered into the installation restoration site database that is part of
the NAS Whidbey Island planning and management model. These restrictions would
include special requirements for any other construction activity that may disturb
contaminated soil, including health and safety plans, environmental protection plans, and
waste management plans. Installation of drinking water wells would be prohibited over
the area where site-related contaminant levels in groundwater exceed cleanup levels. In
the event of property transfer, restrictive covenants on the property would be recorded
with the Island County register of deeds. The covenants would be binding on the
owner's successors and assignees, would place limiting conditions on property
conveyance, would prohibit well construction except for monitoring purposes, and would
restrict land use and construction activity that would disturb subsurface soil. Covenants
would also require notice to environmental regulatory agencies (e.g., the EPA, Ecology,
or their designees) of any intent to transfer interest, modify its land use, or implement
construction activity; and agency approvals would be required for such actions.
The oil skimming wells would be installed within the zone where floating petroleum
product is present on the groundwater. Active pumping of groundwater would not be
used, in order to avoid (1) smearing the petroleum downward into saturated zone soils,
where it would become unrecoverable, and (2) the need for groundwater treatment
(which was shown in the feasibility study report to be expensive for the protection
gained). The wells would be designed to operate with skimming devices that collect oil
(liquid-phase hydrocarbons) and prevent the collection of groundwater. The collected oil
would be containerized for transport to an off-site recycling or treatment facility. The
containerized material would be sampled and analyzed to determine appropriate
treatment and recycling requirements. If recycling is not possible, then the collected oil
would be treated and/or disposed of in accordance with state and federal regulations.
The oil skimming wells would be operated until it becomes impractical to recover
significant amounts of oil. It is estimated that the skimming would be completed in less
than 5 years.
Petroleum-contaminated soil excavated during the removal of the oil/water separator
would be backfilled into the excavation. Confirmation samples would not be collected
from the excavated soil or the limits of excavation.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity. Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 1U3
CTO 0162
The ash piles at Area 31 would be removed by the Navy and disposed of in accordance
with state and federal regulations. No confirmation sampling would be conducted for
the ash pile removal.
No further remedial action would be conducted at the burn pad or the location of the
former UST. The land-use restrictions discussed above would include these areas.
With the removal of petroleum hydrocarbons by the oil skimming wells, concentrations
of petroleum hydrocarbons are expected to eventually decline in the aquifer as the result
of natural biodegradation processes.
A groundwater monitoring program would be conducted to verify that petroleum and
other COCs in groundwater are not migrating and that contaminants have naturally
attenuated before removing or redefining institutional control boundaries. Samples
would be collected annually from up to four monitoring wells, using low-flow sampling
techniques. In the first 4 years of groundwater monitoring, samples would be collected
near the oil/water separator and analyzed for TPH. If after a suitable period of time the
monitoring results indicate that TPH in groundwater is not migrating, the yearly
monitoring would be terminated. In the 5th year, groundwater samples would be
collected throughout the groundwater plume and analyzed for TPH, VOCs, and
manganese.
No active remediation of COCs dissolved in groundwater is included in this alternative;
however, natural attenuation is expected to occur. Because this alternative would result
in some remaining exceedances of cleanup levels in soil and groundwater, long-term
monitoring of groundwater would be required no less frequently than every 5 years.
Estimated costs for Alternative 2 are the following, assuming 5 years of operation and a
5 percent discount factor:
Capital cost: $143,000
Present value O&M costs: $114,000
Total present worth: $257,000
9.3.3 Alternative 3—Oil Skimming and Bioventing
Alternative 3 would address RAOs for the site by means of the same actions and
rationale described for Alternative 2, except that, in addition,-bioventing treatment
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
^v"~*'~acf Nc M50>|7* °o .TXO^O^ PatTP 104
CTO 0162
technology would further reduce potential petroleum sources in the vicinity of the
oil/water separator. These actions would remove or treat a large portion of the source
of groundwater contamination.
The bioventing process would treat petroleum-contaminated soil in the vadose zone
surrounding the oil/water separator. Bioventing is an in situ treatment technology that
involves the use of a vacuum pump or blower to introduce air into the vadose zone
through wells or trenches to promote or enhance the natural biodegradation processes of
native aerobic bacteria in the soil. Bacteria that degrade petroleum hydrocarbons are
generally present in the soil at older petroleum spill sites; however, the degradation rates
are usually slow because the bacteria have a limited oxygen supply. When air is
introduced into such an environment, the oxygen-limited conditions are alleviated, and
the biodegradation rates are typically enhanced substantially. The scientific literature
includes descriptions of various sites where bioventing has successfully degraded
petroleum hydrocarbons contaminating the vadose zone, even without external
applications to enhance soil moisture, nutrient, and temperature conditions.
Bioventing uses similar equipment as soil vapor extraction, but the operation of the
equipment differs. In soil vapor extraction, a vacuum pump withdraws soil vapor at
relatively high rates to promote volatilization and removal of volatile compounds from
the soil. In bioventing, air is introduced into the soil zone at much lower rates, sufficient
only to provide the oxygen needed for biodegradation. Furthermore, in bioventing, the
air may be introduced by a blower with injection wells. The air supply system for a
bioventing process is designed to minimize or eliminate the need to control emissions.
Bioventing was selected for this alternative rather than soil vapor extraction because
bioventing provides better treatment of the heavier petroleum compounds that are not
volatile and eliminates the expense of air emissions controls.
The bioventing process would operate in conjunction with the oil skimming system
described for Alternative 2, after excavation and removal of the oil/water separator.
Alternative 3 would include all the actions described for Alternative 2; in summary,
Alternative 3 includes the following actions:
• Oil skimming wells and off-site treatment or recycling of skimmed product
• Removal and off-site disposal of oil/water separator
• Backfilling of any excavated soil
31620\9605.040\TE\'T
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Enffineerinp Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 rage iU5
CTO0162
• Bioventing of vadose zone soils near the oil/water separator
• Removal of ash piles from the site
• Institutional controls as described for Alternative 2
• Groundwater monitoring as described for Alternative 2
The Navy would conduct a bioventing treatability study to determine the potential
effectiveness of bioventing. If the results showed that bioventing could effectively treat
vadose zone soils and achieve the soil RAOs at Area 31, the Navy would fully implement
bioventing near the oil/water separator.
If bioventing were fully implemented, system performance would be periodically
evaluated. Typically, this is accomplished through respirometry testing, in which
biological activity is measured by analyzing soil gases for oxygen uptake and carbon
dioxide generation. Shutdown of the bioventing system would occur when the majority
of the vadose zone petroleum has degraded and significant biological activity is no longer
present.
No active remediation of COCs dissolved in groundwater is included in this alternative.
Because this alternative would result in some remaining exceedances of cleanup levels in
soil and groundwater, a periodic review of the environmental data would be required no
less frequently than every 5 years.
Estimated costs for Alternative 3 are the following:
Capital cost: $350,000
Present value O&M costs: $242,000
Total present worth: $592,000
9.3.4 Alternative 4—Soil Excavation and Removal
Alternative 4 features excavation of contaminated soil and ash piles to attempt to
achieve state cleanup levels, eliminate potential ecological risks posed by the surface soil
and ash, and reduce future risks posed by organic chemicals in the subsurface soil and
groundwater. These actions would remove the majority of the known sources of
groundwater contamination. This alternative also includes the removal of the oil/water
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
C^"^2cf KV ^^•4'74-89-r»-cn9^ Page 106
CTO 0162
separator, the implementation of institutional controls, and groundwater monitoring as
described for Alternative 2.
The soil removal action would include the top 2 feet of contaminated surface soils, the
ash piles, and subsurface soil at the oil/water separator. The subsurface soils would be
excavated from the contaminated zone adjacent to and below the oil/water separator.
The excavation would include the full areal extent of the petroleum-contaminated vadose
zone and would extend down to and several feet below the water table. Product that
floats on the groundwater at the bottom of the excavation pit would be skimmed and
containerized for off-site treatment or recycling; treatment and recycling of product
would be implemented as discussed for Alternative 2.
The excavated soils and ash would be tested and treated off site, as needed, to comply
with state and federal regulations for land disposal. Depending on test results, the soil
and ash would be disposed of at the Area 6 landfill (on site) or at a permitted landfill
(off site).
In summary, this alternative would include the following actions:
• Removal of the ash piles
• Removal of contaminated surface soils
• Removal of the oil/water separator
• Removal of contaminated soil around the oil/water separator down to the
water table, and skimming of floating petroleum product from the bottom
of the excavation pit
• Treatment/disposal of skimmed product and excavated soil at permitted
off-site facilities
• Institutional controls as described for Alternative 2
• Groundwater monitoring as described for Alternative 2
No active remediation of COCs dissolved in groundwater is included in this alternative.
Because this alternative would result in some remaining exceedances of cleanup levels in
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-929D 1"*^ 1C7
CTO0162
soil and groundwater, a periodic review of the environmental data would be required no
less frequently than every 5 years.
Estimated costs for Alternative 4 are the following, assuming 5 years of operation and a
5 percent discount factor:
Capital cost: $5,091,000
Present value O&M costs: $67,000
Total present worth: $5,158,000
These costs assume disposal of excavated soils at a RCRA Subtitle C hazardous waste
landfill. This is a conservative assumption; a RCRA Subtitle D solid waste landfill may
be able to accept the excavated soils at a lower cost.
10.0 COMPARATIVE ANALYSIS OF ALTERNATIVES
The EPA has established nine criteria for the evaluation of remedial alternatives:
• Overall protection of human health and the environment
• Compliance with ARARs
• Long-term effectiveness and permanence
• Reduction of toxicity, mobility, or volume through treatment
• Short-term effectiveness
• Implementability
• Cost
• State acceptance
• Community acceptance
The following sections summarize the detailed evaluation of alternatives for each area in
regard to the nine evaluation criteria.
10.1 AREA 1
Each remedial alternative for Area 1 is discussed in relation to the EPA evaluation
criteria in the following subsections.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy GLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Co^—. :T_ "Zl"7* °° ^-:9?95 Paee 108
CTO 0162
10.1.1 Overall Protection of Human Health and the Environment
Under Alternative 1, long-term protection of human health and the environment would
not be ensured if the site is disturbed by future development. Also, although it is
believed that COCs found in groundwater are not affecting the marine environment,
Alternative 1 includes no further sampling or monitoring to verify this.
Alternative 2 would provide overall protection of human health and the environment by
preventing future disturbance of the landfill, protecting the existing wetlands from future
development, and confirming that COCs in groundwater do not adversely affect the
marine environment.
Alternative 3 would be most protective of human health by eliminating the potential for
human contact with COCs in the landfill contents. The cap and seawall considered
under Alternative 3 would provide Coverall protection of the environment by reducing the
potential for contaminant transport from the landfill. However, the cap would cause
destruction of the wetlands present on top of the landfill. Wetlands are known to
remove contaminants, and the loss of the wetland would increase contaminant transport
to the straits as a result of storm drainage presently entering the wetland.
10.1.2 Compliance With Applicable or Relevant and Appropriate Requirements
COCs in soil exceed state cleanup levels under MTCA. COCs detected in groundwater
exceed marine water quality standards for protection of the environment (WAC 173-
201A and the Federal Clean Water Act). However, it is not known whether these
exceedances occur at the point of compliance (i.e., the area where groundwater
discharges to marine water).
Alternative 1 would not include cleanup actions or provide institutional controls to
prevent human exposures to COCs remaining on site, and it would not include
groundwater monitoring to determine whether surface water ARARs are exceeded.
Because Alternative 1 would not protect human health and the environment and would
not comply with ARARs, it is not considered or discussed further under the remaining
evaluation criteria.
Alternatives 2 and 3 would comply with state and federal ARARs. Compliance with
state cleanup regulations would be achieved through the institutional controls,
monitoring, and containment measures proposed in Alternatives 2 and 3.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 109
CTO 0162
10.1.*3 Long-Term Effectiveness and Permanence
Alternative 2 would be effective in the long term by preventing future development that
could disturb the landfill and possibly mobilize COCs. The existing wetlands would
continue to remove COCs from surface water, and long-term reductions in
concentrations of COCs in soil, sediments, and groundwater are expected to occur
through natural attenuation mechanisms.
Alternative 3 would provide long-term protection against disturbance of the landfill, but
continual maintenance of the cap would be necessary. Long-term negative effects are
possible as a result of the destruction of the wetlands caused by cap construction.
10.1.4 Reduction of Toxicity, Mobility, or Volume Through Treatment
Alternatives 2 and 3 do not include a treatment component.
10.1.5 Short-Term Effectiveness
No short-term risks are associated with Alternative 2. RAOs would be achieved in a
short timeframe via implementation of institutional controls and monitoring.
Under Alternative 3, short-term risks to construction workers would be rninimized by
standard health and safety precautions. Construction would pose potential risks to
wildlife and could cause sediment transport to the environment. Cap construction would
take approximately 6 months.
10.1.6 Implementability
Technically, Alternatives 2 and 3 are readily implementable. However, the wetlands
destruction and shoreline modification included in Alternative 3 could make this
alternative difficult to implement administratively.
10.1.7 Cost
The estimated present worth cost of Alternative 2 is $134,000. The estimated present
worth cost of Alternative 3 is $2,191,000.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 110
CTO 0162
The cost estimates were prepared using costing techniques that typically achieve an
accuracy of + 50 percent to -30 percent for a specified scope of actions. Additional
uncertainty in the costs is introduced by variations in the volumes and other quantities
assumed for the estimates.
10.1.8 State Acceptance
Ecology has been briefed on the remedial investigations, feasibility studies, and the
proposed plan and concurs with the selected remedies at OU 5.
10.1.9 Community Acceptance
The Restoration Advisory Board has been involved in the review and comment process
of all project documents leading to this ROD. On October 24, 1995, the Navy held an
open house and public meeting to discuss the proposed plan for final action at OU 5.
The public comment period extended from October 10 to November 9, 1995. No public
comments were received.
10.2 AREA 52
At Area 52, the range of response actions is limited to no action or a collection system
to remove floating petroleum product from groundwater. As discussed in Section 9, the
results of the treatability study have shown that oil skimming without groundwater
extraction is the only practical way to remove the floating petroleum product.
Accordingly, only two alternatives were developed—the no-action alternative and oil
skimming combined with institutional controls.
Each remedial alternative for Area 52 is discussed in relation to the EPA evaluation
criteria in the following subsections.
10.2.1 Overall Protection of Human Health and the Environment
Under Alternative 1, long-term protection of human health and the environment would
not be ensured if the site is disturbed by future development. Also, although it is
believed that COCs found in groundwater are not affecting the marine environment,
Alternative 1 includes no further sampling or monitoring to verify this.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision'No.: 0
Engineering Field Activity. Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 rage m
CTO 0162
Alternative 2 would provide overall protection of human health and the environment by
preventing future disturbance of subsurface soils, removing the floating petroleum
product, and ensuring that COCs in groundwater do not adversely affect the marine
environment.
10.2.2 Compliance With Applicable or Relevant and Appropriate Requirements
Petroleum in soil exceeds state cleanup levels under MTCA. COCs detected in
groundwater exceed marine water quality standards for protection of the environment
(WAC 173-201A and the Federal Clean Water Act). However, it is not known whether
these exceedances occur at the point of compliance (i.e., the mixing zone where
groundwater discharges to marine water).
Alternative 1 would not include cleanup actions or provide institutional controls to
prevent human exposures to COCs remaining on site and would not include groundwater
monitoring to determine whether surface water ARARs are exceeded. Because
Alternative 1 would not protect human health and the environment and would not
comply with ARARs, it is not considered or discussed further under the remaining
evaluation criteria.
Alternative 2 would comply with state and federal ARARs. Compliance with state
cleanup levels would be achieved through the institutional controls and monitoring
proposed in Alternative 2.
10.2.3 Long-Term Effectiveness and Permanence
Alternative 2 would be effective in the long term by permanently removing the floating
petroleum product and by preventing future construction or development that could
cause exposure to residual petroleum in subsurface soils. Long-term reductions in
concentrations of petroleum and related COCs in soil and groundwater are expected to
occur through natural attenuation mechanisms.
10.2.4 Reduction of Toxicity, Mobility, or Volume Through Treatment
Alternative 2 includes treatment by recycling of the floating petroleum product recovered
from the site. Reading would return the petroleum to beneficial re-use, permanently
reducing its toxiciry, mobility, and volume in the environment.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest . Date: 05/21/96
•^ ,...,<-,.,...,.< >,T.-_ xyriXT^ O^i *-N ^^r^c
CTO 0162
10.2.5 Short-Term Effectiveness
Alternative 2 would not cause significant short-term risks during the construction or
operation of the recovery system. It would achieve the RAOs in a short timeframe by
implementing institutional controls to prevent potential exposures and through
monitoring. Recovery of the floating petroleum product is expected to take several
months or years. Therefore, numeric cleanup goals for soil and groundwater are not
expected to be achieved for several years.
10.2.6 Implementability
Alternative 2 is readily implementable.
10.2.7 Cost
»
The estimated present worth cost of Alternative 2 is $213,000.
The cost estimates were prepared using costing techniques that typically achieve an
accuracy of +50 percent to -30 percent for a specified scope of actions. Additional
uncertainty in the costs is introduced by variations in the volumes and other quantities
assumed for the estimates.
10.2.8 State Acceptance
Ecology has been briefed on the remedial investigations, feasibility studies, and the
proposed plan and concurs with the selected remedies at OU 5.
10.2.9 Community Acceptance
The RAB has been involved in the review and comment process of all project documents
leading to this ROD. On October 24, 1995, the Navy held an open house and public
meeting to discuss the proposed plan for final action at OU 5. The public comment
period extended from October 10 to November 9, 1995. No public comments were
received.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity. Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 rage i^
CTO0162
10.3 AREA 31
Each remedial alternative for Area 31 is discussed in relation to the EPA evaluation
criteria in the following subsections.
10.3.1 Overall Protection of Human Health and the Environment
Alternative 1 includes no measures to prevent future human health risks posed by COCs
in ground water or to prevent the spread of COCs in groundwater. Alternative 1,
therefore, would not protect human health. The only potential ecological risk identified
for Area 31 was to small mammals; animals higher on the food chain were not identified
as an ecological risk. Therefore, Alternative 1 would be protective of the environment.
Alternatives 2 and 3 would providq overall protection of human health and the
environment by preventing human exposures to COCs in soil and groundwater, and by
removing and treating the largest sources of COCs that may cause contamination to
spread in groundwater.
Alternative 4 would be most protective of human health and the environment. Under
Alternative 4, most of the known contamination in surface soil and subsurface soil would
be permanently removed from the site, thereby preventing human exposures and
eliminating the potential ecological risks to small mammals.
10.3.2 Compliance With Applicable or Relevant and Appropriate Requirements
COCs in soil and groundwater exceed state cleanup levels under MTCA Alternative 1
includes no actions to address these exceedances or prevent exposures and, therefore,
would not comply with ARARs. Because Alternative 1 would not protect human health
and the environment and would not comply with ARARs, it is not considered or
discussed further under the remaining evaluation criteria.
Alternatives 2, 3, and 4 would comply with state and federal ARARs. However, each of
these alternatives would result in some remaining exceedances of cleanup levels on site.
These exceedances would be addressed through institutional controls and monitoring to
assess the effectiveness of the source reduction actions in controlling the spread of COCs
and possibly accelerating their natural attenuation.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62C-^-S?-!? 02°5 P*?? m
CTO 0162
10.3.3 Long-Term Effectiveness and Permanence
Alternatives 2, 3, and 4 would each be effective in the long term in preventing the spread
of COCs in groundwater and preventing human exposures through institutional controls.
Alternatives 2, 3, and 4 would each permanently remove the oil/water separator and the
petroleum floating on groundwater, which are the largest sources of contamination.
Alternative 3 would provide additional effectiveness over Alternative 2 by permanently
destroying petroleum hydrocarbons present in the vadose zone. Alternative 4 would
have the greatest long-term effectiveness, because it would permanently remove
contaminated surface soil, subsurface soil, and floating petroleum product. Natural
attenuation will occur in Alternatives 2 and 3 but may take a long time and may not be
as effective as Alternative 4.
10.3.4 Reduction of Toxicity, Mobility, or Volume Through Treatment
>
Alternatives 2, 3, and 4 each include treatment (recycling or incineration) of the floating
petroleum product recovered from the site. Recycling would allow beneficial re-use of
the petroleum, whereas incineration would permanently destroy the petroleum.
Alternative 3 provides additional treatment of vadose zone soils by bioventing, which
would permanently destroy the residual petroleum in the vadose zone. Alternative 4
would include treatment of excavated soil to reduce the mobility of contaminants, but the
treatment would be conducted only if required prior to landfilling the soil.
10.3.5 Short-Term Effectiveness
None of the alternatives is expected to cause significant short-term risks to the nearby
private residences, workers, or environment during remediation because the actions
involve common remedial construction activities that are readily controlled.
Alternative 4 has the greatest potential for short-term impacts as a result of construction
because it involves deeper and more extensive excavation (about 20 feet down to the
water table at the oil/water separator) than Alternatives 2 and 3. Proper system design
will minimize or eliminate vapor emissions from the bioventing process.
Each alternative would achieve RAOs in a short timeframe via implementation of
institutional controls that would prevent the exposures of concern. No alternative is
expected to attain groundwater numeric cleanup levels in a short timeframe because
residual contamination will be left at the site in all the alternatives. No alternative
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 115
CTO 0162
includes actions for active remediation of COCs dissolved in groundwater. Alternatives 2
and 3 each involve excavation and disposal of some soil near the oil/water separator, as
needed to remove the oil/water separator. Remedial goals for soil would be quickly met
in those areas where soil is to be excavated for off-site disposal; this applies most
particularly to Alternative 4, which would use soil removal as the principal means to
eliminate most of the contamination at the site. Also, under Alternative 4, remedial
goals for petroleum in groundwater would be achieved in a short timeframe, although
some dissolved COCs may persist for months or years. The estimated period of
operation is 5 years or less for both the oil skimming and bioventing systems.
103.6 Implementability
There are no major differences among the three alternatives in terms of difficulty of
implementation that would significantly favor one alternative over another. Each
alternative would use common, readily available equipment and construction techniques.
10.3.7 Cost
The estimated present worth cost of Alternative 2 is $257,000. The estimated present
worth cost of Alternative 3 is $592,000. The estimated present worth cost of
Alternative 4 is $5,158,000.
The cost estimates were prepared using costing techniques that typically achieve an
accuracy of +50 percent to -30 percent for a specified scope of actions. Additional
uncertainty in the costs is introduced by variations in the volumes and other quantities
assumed for the estimates.
10.3.8 State Acceptance
Ecology has been briefed on the remedial investigations, feasibility studies, and the
proposed plan and concurs with the selected remedies at OU 5.
10.3.9 Community Acceptance
The RAB has been involved in the review and comment process of all project documents
leading to this ROD. On October 24, 1995, the Navy held an open house and public
meeting to discuss the proposed plan for final action at OU 5. The public comment
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89--D-9295 ' P^e 1.16
CTO 0162
period extended from October 10 to November 9, 1995. No public comments were
received.
11.0 THE SELECTED REMEDY
11.1 AREA 1
The Navy has chosen Alternative 2 (limited action—institutional controls and
monitoring) as the selected remedy at Area 1. Alternative 2 is protective of human
health and the environment and provides the best overall effectiveness proportional to its
cost. The institutional controls will prevent potential future human exposure to landfill
contents or groundwater by preventing future development that may disturb the landfill
and preventing the installation of drinking water wells. The environmental monitoring
will meet the RAO of determining compliance with water quality standards for marine
water at the point where groundwater discharges to marine water. The major
components of the selected remedy are discussed in the following paragraphs.
To prevent residential development or the installation of drinking water wells, land-use
restrictions will be entered into the installation restoration site database that is part of
the NAS Whidbey Island planning and management model. These restrictions will
include special requirements for any other construction that may disturb the landfill,
including health and safety plans, environmental protection plans, and waste
management plans. The Navy will implement these restrictions. In the event of property
transfer, restrictive covenants on the property will be recorded with the Island County
register of deeds. The covenants will be binding on the owner's successors and assignees
and will place limiting conditions on property conveyance, prohibit well construction
except for monitoring purposes, and restrict land use and construction activity that would
disturb the landfill. These restrictions will apply to the landfill plus an appropriate
buffer zone. Covenants will also require notice to the EPA, Ecology, or their designees
of any intent to transfer interest, modify its land use, or implement construction activity;
and agency approvals will be required for such actions.
Continued use of existing security measures will control physical access to Area 1 by the
general public.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Hr.Hir^erir!^ ^'eld Activity Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 117
CTO 0162
An environmental monitoring program will include groundwater sampling and biological
surveys of the beach. In the 1st year, the two inland monitoring wells (MW-18 and
MW-103) will be resampled one time for cyanide, and up to six intertidal groundwater
samples will be collected from seeps along the shoreline. The intertidal seep samples
will be analyzed for total and dissolved inorganics, cyanide, VOCs, and SVOCs to
determine compliance with surface water cleanup levels. The surface water cleanup
levels are shown in Table 12. The point of compliance for obtaining these cleanup levels
is in the seeps along the shoreline. If the results of the intertidal groundwater sampling
indicate compliance with surface water cleanup levels, the sampling will be terminated.
Visual inspections of the physical condition of the landfill bluff will be conducted
annually for the first 5 years and the results documented.
If the results of the 1st year intertidal groundwater sampling indicate that surface water
cleanup levels are not met in the intertidal groundwater seep samples, the following
monitoring program will be instituted: A biological survey of the intertidal zone will be
conducted in the 2nd year. Up to six intertidal groundwater samples will be collected
annually from seeps along the shoreline, beginning in the 2nd year. The intertidal seep
samples will be analyzed for total and dissolved inorganics, cyanide, VOCs, and SVOCs
to determine compliance with surface water cleanup levels. After the 1st year of
monitoring, the Navy and the EPA will consider limiting the chemical analyses in
subsequent years to those chemicals detected during the 1st year. If the results of the
intertidal groundwater seep sampling indicate compliance with surface water cleanup
levels for 2 consecutive years, the annual sampling will be terminated. If compliance
with surface water cleanup levels has not been attained for 2 consecutive years by the
5th year, a biological survey of the intertidal zone will be conducted. Regardless of the
sampling results, visual inspections of the physical condition of the landfill bluff will be
conducted annually for the first 5 years, and the results documented.
A periodic review of the data will be conducted no less frequently than every 5 years. At
the 5-year review, all data will be evaluated by the EPA and the Navy to jointly assess
protection of ecological receptors in the marine environment. The environmental data
will be used to assess the need for further action.
1L2 AREA 52
The Navy has chosen Alternative 2 (oil skimming) as the selected remedy at Area 52.
Since the only other alternative is no action, Alternative 2 is considered more protective
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No N62474-89-D-°295 p?mp. 11,9
CTO 0162
for a reasonable cost, instead of taking no action. Institutional controls will limit human
exposure to subsurface soil containing petroleum above cleanup levels and prevent
human exposure to COC in groundwater above cleanup levels. The environmental
monitoring will meet the RAO of determining compliance with water quality standards
for marine water at the point where groundwater discharges to marine water. Removal
of free product will meet the RAO of preventing the migration of floating petroleum
product from groundwater to marine surface water. The major components of the
selected remedy are discussed in the following paragraphs.
The existing monitoring wells that are screened across the water table surface will be
used as collection points for removal of floating petroleum product. Up to five
additional monitoring/collection wells will be installed to provide additional coverage
near the Jet Engine Test Cell and downgradient, where the plume is expected to
migrate. The exact number and locations of the wells will be determined in the remedial
design. The wells will operate with skimming devices that collect floating petroleum
product and prevent the collection of groundwater. The collected oil will be
containerized for transport to an off-site recycling or treatment facility. The collected oil
will be sampled and analyzed to determine appropriate treatment and recycling
requirements. If recycling is not possible, then the collected oil will be treated and/or
disposed of in accordance with state and federal regulations. The skimming wells will be
operated until it becomes impractical to recover significant amounts of oil.
As a precautionary action, the existing 6-inch-diameter drywell at Area 52 will be
excavated, and the excavation will be backfilled with borrow soils. No confirmation
sampling will be conducted for the drywell removal.
To prevent residential development or the installation of drinking water wells, land-use
restrictions will be entered into the installation restoration site database that is part of
the NAS Whidbey Island planning and management model. These restrictions will
include special requirements for any other construction that may disturb contaminated
soil, including health and safety plans, environmental protection plans, and waste
management plans. The Navy will implement these restrictions. In the event of property
transfer, restrictive covenants on the property will be recorded with the Island County
register of deeds. The covenants will be binding on the owner's successors and assignees
and will place limiting conditions on property conveyance, prohibit well construction
except for monitoring purposes, and restrict land use and construction activity that would
disturb the site. These restrictions will apply to the site plus an appropriate buffer zone.
Covenants will also require notice to the EPA, Ecology, or their designees of any intent
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract N
CTO0162
to transfer interest, modify its land use, or implement construction activity; and agency
approvals will be required for such actions.
Quarterly monitoring of the thickness of the floating petroleum product will be
conducted while skimming is occurring. The measurements of petroleum product will be
timed to coincide with high and low seasonal water levels.
An environmental monitoring program will include intertidal groundwater seep sampling
and biological surveys of the beach. Intertidal groundwater seep samples will be
collected biannually, in years 1, 3, and 5 following the signing of the ROD. In each
sampling event, up to six intertidal groundwater samples will be collected from seeps
along the shoreline and analyzed for VOCs, SVOCs, and TPH to determine compliance
with surface water cleanup levels. After the 1st year of monitoring, the Navy and the
EPA will consider limiting chemical analyses in subsequent years to those chemicals
detected during the 1st year. The Surface water cleanup levels are shown in Table 13.
The point of compliance for attaining these cleanup levels is in the seeps along the
shoreline. Biological surveys of the intertidal zone will be conducted in years 2 and 5
following the signing of the ROD.
An environmental protection plan will be developed by the Navy to ensure that
contaminant transport or human exposures do not occur as a result of remediation
activities and that proper waste handling and disposal techniques are used during
implementation of this remedy. A periodic review of the monitoring data will be
conducted no less frequently than every 5 years. At the 5-year review, all data will be
evaluated by the EPA and the Navy to jointly evaluate the effectiveness of the selected
remedy and assess the protection of ecological receptors in the marine environment.
11.3 AREA 31
The Navy has chosen Alternative 3 (bioventing and oil skimming) as the selected remedy
at Area 31. Alternative 3 is protective of human health and the environment and
provides the best overall effectiveness proportional to its cost. The institutional controls
will limit human exposure to surface soil and subsurface soil and prevent exposure to
groundwater containing COCs above cleanup levels. The area covered by the
institutional controls includes the portion of the site where the UST was removed. The
oil skimming, oil/water separator removal, and bioventing actions will meet the RAOs of
reducing the sources of petroleum hydrocarbons in soil that may cause groundwater
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page i^u
CTO 0162
contamination and stopping the spread of contaminants in groundwater. Once these
sources of contamination are removed, natural attenuation is expected to slowly reduce
contaminant concentrations in groundwater. In the meantime, institutional controls will
meet the RAO of preventing human exposure to COCs in groundwater. The major
components of the selected remedy are discussed in the following paragraphs.
To prevent residential development or the installation of drinking water wells, land-use
restrictions will be entered into the installation restoration site database that is part of
the NAS Whidbey Island planning and management model. These restrictions will
include special requirements for any other construction that may disturb contaminated
soil, including health and safety plans, environmental protection plans, and waste
management plans. The area covered by the land-use restrictions includes the portion of
the site where the UST was removed. Installation of drinking water wells would be
prohibited over the area where sit^-related contaminant levels in groundwater exceed
cleanup levels. The Navy will implement the restrictions. In the event of property
transfer, covenants on the property will be recorded with the Island County register of
deeds. The covenants will be binding on the owner's successors and assignees and will
place limiting conditions on property conveyance, prohibit well construction except for
monitoring purposes, and restrict land use and construction activity that would disturb
subsurface soil. Covenants will also require notice to the EPA, Ecology, or their
designees of any intent to transfer interest, modify its land use, or implement
construction activity; and they will require agency approvals for such actions.
Oil skimming wells will be installed within the zone in which floating petroleum product
is present on the groundwater. The wells will operate with skimming devices that collect
oil (liquid-phase hydrocarbons) and prevent the collection of groundwater. The collected
oil will be containerized for transport to an off-site recycling or treatment facility. The
collected oil will be sampled and analyzed to determine appropriate treatment and
recycling requirements. If recycling is not possible, then the collected oil will be treated
and/or disposed of in accordance with state and federal regulations. The skimming wells
will be operated until it becomes impractical to recover significant amounts of oil.
The oil/water separator will be excavated, and any associated piping will be permanently
capped or removed. Any liquids and sludges found in the tank, along with any rinsates,
will be removed, designated, and disposed. The empty tank will be cleaned and
decontaminated. The cleaned tank will be sent off site, either for recycling as scrap
metal or for disposal in an RCRA solid waste (Subtitle D) landfill. The oil/water
separator is not considered an UST. Petroleum-contaminated soil excavated during
31620X9605.040\TEXT
-------
HAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field ^cuvu^, No/iii™^ Date: 05/21/95
Contract No. N62474-89-D-9295 Page 121
CTO0162
removal of the oil/water separator will be backfilled into the excavation. Confirmation
samples will not be collected from the excavated soil or the limits of excavation.
No further remedial action will be conducted at the burn pad or the location of the
former UST. The land use restrictions discussed above will include these areas.
The ash piles at Area 31 will be removed by the Navy and disposed of in accordance
with state and federal regulations. No confirmation sampling will be conducted for the
ash pile removal. In the event the drainage ditch sediments near sampling location
SD-12 are removed, the material will be characterized and disposed of in accordance
with state and federal regulations.
A groundwater monitoring program will be conducted to verify that petroleum and other
COCs in groundwater are not migrating and that contaminants have naturally attenuated
before removing or redefining institutional control boundaries. Samples will be collected
annually from up to four monitoring wells, using low-flow sampling techniques. In the
first 4 years of groundwater monitoring, samples will be collected near the oil/water
separator and analyzed for TPH. If after a suitable period of time the monitoring results
indicate that TPH in groundwater is not migrating, the yearly monitoring will be
terminated. In the 5th year, groundwater samples will be collected throughout the
groundwater plume and analyzed for TPH, VOCs, and manganese.
The Navy will conduct a bioventing treatability study to determine the potential
effectiveness of bioventing. If the results show that bioventing could effectively treat
vadose zone soils and achieve the soil RAOs at Area 31, the Navy will fully implement
bioventing near the oil/water separator. If bioventing is fully implemented, appropriate
health and safety measures will be followed, including the possibility of an emissions
offgas monitoring program to verify that air quality standards are not exceeded. System
performance will be periodically evaluated. Shutdown of the bioventing system will
occur when significant biological activity is no longer present.
An environmental protection plan will be developed to ensure that contaminant
transport or human exposures do not occur as a result of remediation activities and that
proper waste handling and disposal techniques are used during implementation of this
remedy.
Exceedances of the groundwater cleanup levels in some wells are expected to persist
on site for some time. These exceedances will be addressed through institutional
controls to prevent groundwater use. The effectiveness of the remedy in achieving the
groundwater RAOs will be evaluated primarily in regard to preventing the spread of
31620\9605.040\TEXT .
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
^OiiLi dCt 1NQ. i NO^^r /l-O>-i-y->^^_»
CTO 0162
COCs at concentrations above the groundwater cleanup levels. A periodic review of the
monitoring data will be conducted no less frequently than every 5 years. At the 5-year
review, all data will be evaluated by the EPA and Navy to jointly assess the effectiveness
of the selected remedy.
12.0 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 practicable. 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. The
selected remedies for OU 5 are discussed in terms of these statutory requirements in this
section.
12.1 AREA 1
12.1.1 Protection of Human Health and the Environment
The selected remedy for Area 1 will protect human health and the environment through
institutional controls that will prevent future disturbance of the landfill and protect the
existing wetlands from future development. Monitoring will evaluate whether COCs in
groundwater are adversely affecting the marine environment.
12.1.2 Compliance With ARARs
The selected remedy for Area 1 will comply with federal and state ARARs that have
been identified. No waiver for any ARAR is being sought or invoked for any component
of the selected remedy. The ARARs identified for Area 1 are discussed in the following
subsections.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 rage 123
CTO 0162
Chemical-Specific ARARs
State of Washington Hazardous Waste Cleanup—Model Toxics Control Act (MTCA;
WAC 173-340). These regulations are applicable to setting the cleanup standards for soil
and groundwater discharges to surface water. They are relevant and appropriate to the
sediments in the wetlands.
Ambient Water Quality Criteria (Clean Water Act Section 304; Quality Criteria for Water
[U.S. EPA 1986b]). Water quality criteria are relevant and appropriate for surface
waters and groundwater discharges to surface water for the protection of human health
and aquatic life.
Water Quality Standards (Clean Water Act Section 303; 40 CFR 131; WAC 173-201A).
Water quality standards are relevant and appropriate for surface water and groundwater
discharges to surface water for the protection of aquatic life.
State of Washington Water Quality Standards for Surface Waters (WAC 173-201A).
State water quality standards are applicable for the protection of aquatic life in fresh and
marine surface waters. These state standards enforce the requirements of the Clean
Water Act. They are relevant and appropriate to the discharge of groundwater to
surface water.
Location-Specific ARARs
Federal Executive Order 11990 (40 CFR Part 6, Appendix A). This requirement is
applicable to the actions that may affect the wetlands at Area 1. It requires that all
possible actions be taken to avoid harming the wetlands.
The Endangered Species Act (16 USC 1531 promulgated by 33 CFR 320-330). This act
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 1 will not affect critical habitat of these species.
State Minimum Standards for the Construction and Maintenance of Wells (WAC 173-
160). These standards are applicable and prohibit construction of drinking water wells
within 1,000 feet of a solid waste landfill.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Coutraa No. N62-'74-C? C ?:?5 ' p*ge 1.74
CTO 0162
Action-Specific ARARs
State Minimum Standards for the Construction and Maintenance of Wells (WAC 173-
160). These standards are applicable for construction, testing, and abandonment of
resource protection wells, such as monitoring wells.
12.1.3 Cost Effectiveness
The selected remedy for Area 1 is cost effective because it has been determined to
provide overall effectiveness proportional to its cost, with an estimated present worth
cost of $134,000. The capping alternative considered for Area 1 would cost
approximately 16 times as much as the selected remedy and may have a net negative
impact on the environment due to destruction of wetlands (which are located on top of
the landfill) and loss of habitat. Therefore, the selected remedy represents a reasonable
value for the money that will be spent.
12.1.4 Utilization of Permanent Solutions and Treatment Technologies to the Maximum
Extent Practicable
The selected remedy represents the maximum extent to which permanent solutions and
treatment technologies can be utilized in a cost-effective manner for Area 1. 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 requirement to
use permanent solutions to the maximum extent practicable. However, treatment was
not found to be practicable at Area 1 because of the heterogeneous nature of the landfill
and the relatively low concentrations of chemicals.
12.1.5 Preference for Treatment as a Principal Element
The selected remedy for Area 1 does not satisfy the preference for treatment to address
the principal threats posed by the site. As explained above, treatment was not found to
be practicable at Area 1.
31620\9605.040TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 12s
CTO 0162
12.2 AREA 52
12.2,1 Protection of Human Health and the Environment
The selected remedy for Area 52 will protect human health and the environment through
institutional controls that will prevent future exposures to petroleum-contaminated
subsurface soils and via removal and treatment of the floating petroleum product that is
the largest source of contamination. The potential for future discharge of petroleum or
other COCs to marine surface water will be reduced, and monitoring will ensure that
COCs in groundwater are not adversely affecting the marine environment.
12.2.2 Compliance With ARARs
The selected remedy for Area 52 \vill 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 Area 52 are discussed in the
following sections.
Chemical-Specific ARARs
State of Washington Hazardous Waste Cleanup—Model Toxics Control Act (MTCA;
WAC 173-340). These regulations are applicable to setting the cleanup standards for soil
and groundwater discharges to surface water.
Ambient Water Quality Criteria (Clean Water Act Section 304; Quality Criteria for
Water [U.S. EPA 1986b]). Water quality criteria are relevant and appropriate for
surface waters and groundwater discharges to surface water for the protection of human
health and aquatic life.
Water Quality Standards (Clean Water Act Section 303; 40 CFR 131; WAC 173-201A).
Water quality standards are relevant and appropriate for surface water and groundwater
discharge to surface water for the protection of aquatic life.
State of Washington Water Quality Standards for Surface Waters (WAC 173-201A).
State water quality standards are applicable for the protection of aquatic life in fresh and
marine surface waters. These state standards enforce the requirements of the Clean
Water Act. They are relevant and appropriate to the discharge of groundwater to
surface water.
31620\9605.Q40\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Coniraci No. iNO^T74-o9-Z/-?29j ^'^.^ in/c
CTO 0162
Location-Specific ARARs
The Endangered Species Act (16 USC 1531 promulgated by 33 CFR 320-330). This act
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 52 will not affect critical habitat of these species.
Federal Coastal Zone Management Act (16 USC 1451). The requirements of this act are
applicable to any construction activities at Area 52. Proposed actions must be consistent
with the state coastal zone management plan (i.e., Washington's Shoreline Management
Act).
Washington Shoreline Management Act (RCW 90.58; WAC 173-14, 16, 22). These
regulations are applicable to any construction activity at Area 52. Proposed actions must
be consistent with the policies arid goals of the state shoreline management program and
with the policies and shorelands use designations of the local shoreline master plan.
Provisions also apply to wetlands.
State Minimum Standards for the Construction and Maintenance of Wells (WAC 173-
160). These standards are applicable and prohibit construction of drinking water wells
within 1,000 feet of a solid waste landfill.
Action-Specific ARARs
State Minimum Standards for the Construction and Maintenance of Wells (WAC 173-
160). These standards are applicable for construction, testing, and abandonment of
resource protection wells, such as monitoring and extraction wells.
State of Washington Dangerous Waste Regulations (WAC 173-303). These regulations
specify waste identification, storage, manifest, transport, treatment, and disposal
requirements for solid waste that may contain hazardous substances. These requirements
are applicable to recovered petroleum generated during remediation of Area 52, if the
recovered petroleum cannot be used for its intended purpose.
12.2.3 Cost Effectiveness
The selected remedy for Area 52 is cost effective because it has been determined to
provide overall effectiveness proportional to its cost, with an estimated present worth
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page 127
CTO0162
cost of $213,000. The selected remedy is the only alternative that achieves the RAOs for
Area 52.
12.2.4 Utilization of Permanent Solutions and Treatment Technologies to the Maximum
Extent Practicable
The selected remedy represents the maximum extent to which permanent solutions and
treatment technologies can be utilized in a cost-effective manner for Area 52. 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. Recovering the floating petroleum product will permanently
reduce the toxicity, mobility, and volume of the most mobile contaminants at Area 52.
The selected remedy meets the statutory requirement to use permanent solutions to the
maximum extent practical.
12.2.5 Preference for Treatment as a Principal Element
The selected remedy for Area 52 satisfies the preference for treatment to address the
principal threats posed by conditions at the site. Recovery and recycling or treatment of
floating petroleum product will permanently remove the most mobile contaminants at
Area 52.
12.3 AREA 31
12.3.1 Protection of Human Health and the Environment
The selected remedy for Area 31 will protect human health and the environment through
institutional controls that will prevent human exposures to COCs in soil and
groundwater, and through the removal and treatment of the largest sources of COCs that
may cause contamination to spread in groundwater. Monitoring will ensure that COCs
in groundwater are not migrating outside the limits of the institutional controls and that
the institutional controls are maintained as long as the risks remain.
31620X9605. (WO\T EX 1
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Coniraci No. N62474-89-D-9295 p^~ 19Q
CTO 0162
12.32 Compliance With ARARs
The selected remedy for Area 31 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 remedy. The ARARs identified for Area 31 are discussed in the
following sections.
Chemical-Specific ARARs
State of Washington Hazardous Waste Cleanup—Model Toxics Control Act (MTCA;
WAC 173-340). These regulations are applicable to setting the cleanup standards for soil
and ground water. They are relevant and appropriate to ditch sediments and ash.
Safe Drinking Water Act and National Primary Drinking Water Regulations maximum
contaminant levels (MCLs) and maximum contaminant level goals (MCLGs) (40 CFR
141; 57 FR 31776). MCLs and non-zero MCLGs are relevant and appropriate
requirements to setting the cleanup standards for groundwater at Area 31.
Requirements will be met by source control and natural attenuation.
Location-Specific ARARs
Endangered Species Act (16 USC 1531 promulgated by 33 CFR 320-330). This act 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 31 will not affect critical habitat of these species.
Action-Specific ARARs
State Minimum Standards for the Construction and Maintenance of Wells (WAC 173-
160). These standards are applicable for construction, testing, and abandonment of
resource protection wells, such as monitoring and extraction wells.
Hazardous Materials Regulations (49 CFR Subchapter C, Parts 171 to 180). These
regulations address the movement of hazardous materials on public roadways. If waste
generated during the selected remedy is hazardous and must be transported to a
treatment or disposal facility, these rules are considered applicable.
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Er.~r.?eH.ng FieW A /^;^y, Nort> w^$t Date: 05/21/96
Contract No. N62474-89-D-9295 Page 129
CT00162
Federal Resource Conservation and Recovery Act (40 CFR 261, 262, 263, and 268).
These regulations specify waste identification, storage, manifest, transport, treatment, and
disposal requirements for hazardous waste. These requirements are applicable to
recovered petroleum generated during remediation of Area 31.
State of Washington Dangerous Waste Regulations (WAC 173-303). These regulations
specify waste identification, storage, manifest, transport, treatment, and disposal
requirements for dangerous waste. These requirements are applicable to recovered
petroleum generated during remediation of Area 31.
Federal Clean Air Act General Provisions (40 CFR 52) and Puget Sound Air Pollution
Control Authority Regulation 1, Section 9.15. These regulations for the control of
fugitive dust during construction activities are applicable to the excavation actions of the
selected remedy. *
12.3.3 Cost Effectiveness
The selected remedy for Area 31 is cost effective because it has been determined to
provide overall effectiveness proportional to its cost, with an estimated present worth
cost of $592,000. Each of Alternatives 2, 3, and 4 would achieve the RAOs. The
selected remedy (Alternative 3) provides for treatment of a much larger amount of
contamination than Alternative 2, at an incrementally larger cost. Although
Alternative 4 would address the largest amount of contamination, it would cost roughly
eight times as much as the selected remedy. Therefore, the selected remedy represents a
reasonable value for the money that will be spent.
12.3.4 Utilization of Permanent Solutions and Treatment Technologies to the Maximum
Extent Practicable
The selected remedy represents the maximum extent to which permanent solutions and
treatment technologies can be utilized in a cost-effective manner for Area 31. 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. Recovering and recycling (or incinerating) the floating
petroleum product, along with bioventing of vadose zone soils, will permanently reduce
the toxicity, mobility, and volume of the most mobile contaminants at Area 31. The
31620\9605.040\TEXT
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Coiiuaci I^o. N62474-89-D-9295 Page 130
CTO0162
selected remedy meets the statutory requirement to use permanent solutions and
treatment technologies to the maximum extent practicable.
V
12.3.5 Preference for Treatment as a Principal Element
The selected remedy for Area 31 satisfies the preference for treatment to address the
principal threat posed by conditions at the site. The treatment technologies include
recovery of floating petroleum product, recycling or treatment of the petroleum, and
bioventing. These technologies will permanently remove the most mobile contaminants
at Area 31.
13.0 DOCUMENTATION OF SIGNIFICANT CHANGES
The proposed plan released for public comment in October 1995 discussed remedial
action alternatives for the three areas at OU 5 and identified the preferred alternatives.
No significant changes to the selected remedies have occurred.
31620\9605.040\TEAT
-------
-------
APPENDIX A
Responsiveness Summary
-------
-------
NAS WHIDBEY ISLAND, OPERABLE UNIT 5 Final Record of Decision
U.S. Navy CLEAN Contract Revision No.: 0
Engineering Field Activity, Northwest Date: 05/21/96
Contract No. N62474-89-D-9295 Page A-i
CT00162
APPENDIX A
RESPONSIVENESS SUMMARY
On October 24, 1995, the Navy held an open house and public meeting to discuss the
proposed plan for final action at OU 5. The public comment period extended from
October 10 to November 9, 1995. No written or oral public comments were received.
An information repository containing all primary site documents is located at the NAS
Whidbey Island Library, Oak Harbor, Washington.
31620W605 .Q40VAPPEXDIX. A
-------
-------
-------
------- |