EPA/ROD/R10-94/074
December 1993
EPA Superfund
Record of Decision:
N.A.S. Whidbey Island,
Oak Harbor, WA
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. " . ..,
DECLARATION OF THE RECORD OF DECISION
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.
Area 48. Removal of 1,000 cubic yards of surface soil. Excavation win be limited to the top 2 feet of
the soil column at this area. The excavated soil win be disposed at the Area 6 landfill prior to
construction of a multilayer cap at that facility.
.
. Area 49. If and. when the Navy transfers the property to another owner, the deed will contain a
notification that the property contains a past construction and demolition debris landfill.
STATUfORY DETERMINATIONS
The remedial actions will remove soil contamination from OU 4, thereby reducing the potential risk to
human health and the environment and complying with state requirements. The selected remedies are
protective of human health and the environment, comply with federal and state requirements that are legally
applicable or relevant and appropriate to the remedial actions, and are cost-effective. These remedies utilize
permanent solutions and alternative treatment technologies to the maximum extent practicable for this site.
However, because of the volume of contaminated soil and the types of contaminants present, treatment was
not found to be practicable. Therefore, these remedies do not satisfy the statutory preference for treatment
as a principal element of the remedy.. Contaminated soil will be removed from the site and properly'
managed. Because these remedies will not leave hazardous. substances 'on-site above health-based levels, the
five-year review will not apply to this action.
30420\9311,040\10:1
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Signature sheet for the Naval Air Station Whidbey Island Seaplane Base, Operable Unit 4, Record of
Decision between the U.s. Navy and the U.S. Environmental Protection Agency, with concurrence by the
Washington State Department of Ecology. -
- .,
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Signature sheet for the Naval Air Station Whidbey Island Seaplane Base, Operable Unit 4, Record of
Decision between the U.s. Navy and the U.s. Environmental Protection Agency, with concurrence by the
Washington State Department of Ecology.
~~
/7--
z.~ -1' J.
Gerald A. Emison
Acting Regional Administrator, Region 10
United States Environmental Protection Agency
Date
~20\q31I.().10\1e.\1
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Signature sheet for the Naval Air Station Whidbey Island Seaplane Base, Operable. Unit 4, Record of
Decision between the U.S. Navy and the U.S. Environmental Protection Agency, with concurrence by the
Washin~on State Department of Ecology.
o ~u~~ - _.:/: ~. ,-j-C~~~/
Carol Fleskes .
Toxies Cleanup Program
Washington State Department of Ecology
J.~} !;ji / q .~
Date
30420\Q311.()'>O\I(~1
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SEAPLANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract
EQgineering Field Activity, Northwest
Contract.No. N62474-89-D-9295
era 0042
Record of Decision
Date: 12/15/93
Page ix
CONTENTS
Section No.
Page No.
DECLARATION QF THE RECORD OF DECISION. . . . . . . . . . . . . . . . . . . . . . .
. 1
ABBREVIATIONS. AND ACRONYMS ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. xv
1.0 IN1'R.ODUCTION ........................ ~ . . . . . . . . . . . . . . . . . . . .. 1
2.0 SITE NAME, LOCATION, AND DESCRIPTION....... .... .... . . .. . . .. 1
2.1 AREA 39: AUTO REPAIR AND PAINT SHOP. . . . . . . . . . . . . . .. 4
2.2 AREA 41: BUILDING 25 AND BUILDING 26 DISPOSAL
AREA. . . . . .. . . . . . . ~ . . ... . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . .. 4
. 2.3 . AREA 44: SEAPLANE BASE NOSE .HANGAR . . . . . . 0.' . . . . . . .. 7
2.4 AREAS 48 AND 49: SEAPLANE BASE S~ V AGE YARD AND
lANDFIlL . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . .'. . . . . . . . . . . . . .. 7
3.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES .................
10
4.0 COMMUNITY RELATIONS. . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . .
5.0 SCOPE AND ROLE OF OPERABLE UNITS. . . . . ... . . . . ; ~ . . . . . . . . . . ..
'. . '. . .
11
13
6.0 SUMMARY OF SITE CHARAcrERISTICS ......................... . 14
6.1 SITE GEOLOGY, InTIROGEOLOGY, AND SURFACE
WA1ER HYDROLOGY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 14
6.2 NATURE AND E~NT OF CONTAMINANTS. . . . . . . . . . . . .. 18
6.2.1 Soil................................... . . . . . . . . . '.. 19
62.2 Groundwater...................................... 24
6.2.3 Marine Sediment and Mussel Tissue.. . . . . ... . . . . . . . . . . .. 28
6.2.4 Wetland Sediments and Surface Water. . . . . . . . . . . . . . . . .. 34
7.0 SUMMARY OF SITE RISKS ... . . . .. . .. . . .. .. . . . . . .. . . . .. . . . . . . .. 35
7.1 HUMAN HEALTH RISKS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 35
7.1.1 Exposure Assessment. . ~ . . . . . . . . . . . . . . . . . . . . . . . . . . .. 36
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SEAPlANE BASE, OPERABLE UNIT 4
U.s. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0042
Record of Decision
Date:, 12/15/93
Page x
CONTENTS (Continued)
72
7.1.2 Toxicity Assessment. . . . . . . . . . . . . . - . . . . - - - - . . . - . . . .. 40
7.1.3 Risk Characterization. . . . - . . . . - . . . . . . . . - - . - . . - - - . - -. 42
7.1.4 Uncertainty....................................... 48
ECOLOGICAL RISKS. . . . . . . . . . . . . . . . . . . . . - . . . - . . . . - - . .. 49
7.2.1 Exposure Assessment. . . . . . - . . . . - . . . . . - - . . . . . . . - . . .. 49
7.2.2 Toxicity Assessment.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 50
7.23 Risk Characterization. . . . . .. . . . . . . . . . . . . . . . . . . - - . . . - 51
72.4 Uncertainty Analysis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 52
8.0 REMEDIAL ACTION OBJECTIVES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 53
8.1 SOI11) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - . . . . . . . . . - . - . . . .. 54,
8.2 GROUNDW AJER . . . . . . . . . . " . . . . . . . . . . . . . . . . '. . . . . . - . . . - 56
83 MARINE SEDIMENTS. . . . . . . . . . . . . . - . . . . . . . . . . . . . . . . . .. 56
8.4 WETIANDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. - . . . . . . . .. 56
. .
9.0 DESCRIPTION OF AL1ERNATIVES ........... ~ . . . . . . . . . . . . . . . . .. 57
9.1 ALTERNATIVE 1: NO ACTION-AREAS 39, 41, 44, AND 48 . ... 57
9.2 ALTERNATIVE 2: liMITED ACTIONS-AREAS 39, 41, 44, 48,
AND 49 .............................................. 59
93 ALTERNATIVE 3: SO~ COVER-AREA 39 ................ 59
9.4 ALTERNATIVE 4: EXCAVATION, TRANSPORTATION, AND
DISPOSAL (ON STATION OR OFF-SI1E, WITH OR WITHOUT
STABlllZATION)-AREAS 39, 41, 44" AND 48. .............. - 60
" ,
10.0 COMPARATIVE ANALYSIS OF A.L1ER..~Am'ES """'.'0"""", 62
10.1 PROTECTION OF HUMAN HEALlli AND 1HE .
ENVIRON1v1ENT . . . . . . . . . . . . . . ~ . . . . . . . . . . . . . . . . . . . . . . .. 62
10.2 COMPLIANCE WITH ARARs . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 63
103 REDUCTION OF TOXICITY, MOBll.ITY, OR VOLUME
THROUGH TREATMENT. . . . . . . . . . . . . . . . . . . . . . . . . . . . ~ .. 63
10.4 SHORT-TERM EFFECTIVENESS. . . . . . . . . . . . . . . . . . . . . . . . .. 63
10.5 LONG-TERM EFFECTIVENESS AND PERMANENCE... . ..... 64
10.6 IMPLEMENTABIUTY .................................. 64
10.7 COST.. . . . . . . . . . . . . . . . . . - . . . . . . . . . . . . . . . . . . . . . . . . . . .. 64
10.8 STAJE ACCEPTANCE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 66
10.9 COMMUNITY ACCEPTANCE. . . . -. . . . . . . . . . . . . . - . . . . . . .. 66
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SEAPlANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
era 0042
Record of Decision
Date: 12/15/93
Page xi
CONTENTS (Continued)
11.0 THE SELECfED REMEDIES. . . . . . . . . . . . . . . . . ~ . . . . . . . . . . . . . . . ., . 66
12.0 STATUTORY DETERMINATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 67
12.1 PROTEcnON OF HUMAN HEALTH AND THE
ENVIRONMENT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 68
12.2 COMPUANCE Wm-I APPLICABLE OR RELEV ANr AND
APPROPRIATE REQUIREMENTS. . . . . . ~ . . . . . . . . . . . . . . . . .. 68 '
12.2.1 Action-Specific... . . . . . . . . . . . . . . . . . . . . . . . . . . - . . . . .. 68
12.2.2 Chemical-Specific. . . . . . . . . . . . . . . . . . . - . - . . . . . . . . . . .. 69
12.23 Location-Specific.. . . . . . . . . . . . . . . . . . . . . . - . . .'. . . . . . .. 69
12.3 COST EFFECTIVENESS. . . . . . . . . . . - . . . . . . . . . . . . . . . . . . . .. 69
12.4 UTILIZATION OF PERMANENT SOLUTIONS AND
ALTERNATIVE 1REATMENT TECHNOLOGIES OR
RESOURCE ,RECOVERY TECHNOLOGIES TO 1HE ,
MAXIMUM EXTENT PRACTICABLE . ~ . . . . . . . . . . . .'. . . . . . .. '70,
12.5 PREFERENCE FOR 1REATMENT AS PRINCIPAL ELEMENT .. 70
13.0 DOCUMENTATION OF SIGNIFICANT CHANGES. . . . . .. . . . . . . . . . .. 70
ATIACHMENT A ,
RESPONSIVENESS SUMMARY. . . . . . . . . . . . . . . .. 73
O\'ER VIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . " . . . . . . . .'. . . . . . 73
RESPONSE TO COMMENTS. . . . . . . . . . . . . . . . . . . . . . ~ . . . . . . . . .' .. 74
SUMMA.."RY OF COtv-f..MENTS ON PROPOSED PlAN. . . . . . . . . . . . . .. 74
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, ,
SEAPlANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
crO'OO42
Record of Decision
Date: 12/15/93
Page xii
FIGURES
Figure No.
Page No.
1
2
3
4
5
6
7
8
9
10
I...ocati 0 n Map. . . . . . . . . . . . . . . . . . .' . . . . . . . '.' . . . . . . .'. . . . . . . . . . . " 2
Operable Unit 4 .............................................. 3
Area 39, Auto Repair and Paint Shop. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5
Area 41, Buildings 25 and 26 Disposal Area .. . . . . . . . . . . .' . . . . . . . . . . . . .. 6
,Area 44, Seaplane Nose Hangar. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .' . . . . .' 8
Area 48 Salvage Yard and Area 49 Base Landfill. . . . . . . . . . . . . . . . . . . . " 9
Areas 39, 41, and 44 Potentiometric Surface Contour Map. . . . . . . . . . . . .. 16
Areas 48 and 49 Tidal Study Net Flow Direction. . . . . . . . . . . . . . . . . . . .. 17
Area 39-Spatial Distribution of COCS Detected in Surface Soil. .i . . . . . . .. 22
Area 41-Spatial Distribution of COCS Detected in Surface Soil and
Marine Sediments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 23
Area 44-Spatial Distribution of COCS Detected in Surface Soils, Storm
Drain Sediments, ,and Marine Sediments. . . . . . . . . . . . . . . . . . . . . . . . . .. 25 '
Area 48/ 49-Spatial Distribution of COCS Detected in Surface Soil. and ' '.
Marine Sediments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 26
Areas 48 and 49-Proposed Surface Water and Groundwater Sample
l..ocations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 58
11
12
13
TABLES
Table No.
Page No.
1
2
3
4
5
6
Chemicals of Concern in Surface Soil of Seaplane Base. . . . . . . . . . . . . . . .
Chemicals of Concern in Groundwater of Seaplane Base. . . . . . . . . . . . . . .
Comparison of Chemicals of Concern Detected in Surface and Subsurface
Marine Sediment in Areas 41, 44, 48, and 49 (mg/!cg) .................
Marine Sediment Risk Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Summary Data for Chemicals of Concern in Wetland Sediment '
(Areas 48 and 49) (mg/kg) .....................................
Populations, Media, and Routes of Exposure Evaluated at Areas 39, 41, 44,
48, and 49 ............................................... . . .
20' .
27
29
30
34
37
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SEAPLANE BASE, OPERABLE UNIT 4
U.s. Navy CLEAN Contract .
Engineering Field Activity, Northwest.
Contract No. N62474-89-D-9295
era 0042
Record of Decision
Date: 12/15/93
Page xiii
7
8
9
10
11
12 .
13
14.
Exposure Point Concentrations for Chemicals of Potential Human Health
Risk for All Media in Areas 39, 41, 44, 48, and 49 .,......... - . . . . . . . .
Toxicity Values for Chemicals of Concern. . . . . . . . . . . . . . . . . . . . . . . . . .
Area 39-Summary of CanCer and Noncancer Risks. .. - . . . . . . . . . . . - . - .
Area 41-Summary of Cancer and Noncancer Risks. . . . . . . . . . . . . . . . . . .
Area 44-Summary of Cancer and Noncancer Risks .. . . . . . . . . . . . . . . . . .
Areas 48 and 49-Summary of Cancer and Noncancer Risks. . . . . . . . . . . . .
. State of Washington Cleanup Criteria. . . . . . . . . . . . . . . . . . . . . .. . . - . . .
Cost Comparison for Each Alternative by Area. . . . . . . . . . . . . . . . . . . . . .
30420\9311.040\1e.n
39
41
44
45
46
47
54
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SEAPLANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract .
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0042
Record of Decision
Date: 12/15/93
Page xv
ABBREVIATIONS AND ACRONYMS
ARAR
bgs
CERCLA
Applicable or Relevant and Appropriate Requirement
below ground surface
Comprehensive Environmental Response, Compensation, and
Liability Act of 1980 .
chemical of concern
current situation report
cubic yard
United States Department of Defense
: dangerous waste
Washington State Department of Ecology
Engineering Field Activity, Northwest
extremely hazardous waste
. United States Environmental Protection Agency
exposure point concentration
ecological risk assessment
Federal Facilities Agreement
Health Effects Assessment Summary Tables
hazard index
hazard quotient
Hazard Ranking System
Initial Assessment Study
Integrated Risk Information System
Installation Restoration Program
l\o1odel Toxies Control Act (\Vashington State)
Navy Assessment and Control of Installation. Pollutants
Naval Air Station
Naval Facilities Engineering Command
National Oil and Hazardous Substances Pollution
Contingency Plan
National Priorities List
Operable Unit
polycyclic aromatic hydrocarbon
polychlorinated biphenyl
parts per million
COC
CSR
cy
DoD
DW
Ecology
EFA NW
EHW
EPA
EPC
ERA
.FFA
BEAST
III
HQ
. HRS
!AS
IRIS
IRP
MTCA
NACIP
NAS
NAVFACENGCOM
NCP
NPL
OU
PAR
PCB
ppm
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SEAPlANE BASE, OPERABLE UNIT 4
U.s. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0042
Record of Decision
Date: 12/15/93
Page xvi
ABBREVIATIONS AND ACRONYMS (Continued)
RA
RAO
RAS
RCRA
RfC
RID
RI/FS
RME
ROD
SARA
SF
SVOC
TAL
TBC
UCL,
VOC
WAC
risk assessment
remedial action objectives
Routine Analytical Service
Resource Conservation and Recovery Act
reference concentration
reference dose
remedial investigation/feasibility study
reasonable maximum exposure
Record of Decision
Superfund Amendments and Reauthorization Act of 1986
slope factor .
semivolatile organic compound
target analyte list
, to be considered
upper Confidence limit
volatile organic compound
Washington Administrative Code
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SEAPLANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0042
Record of Decision
Dale: 12/15/93
Page 1
DECISION SUMMARY
1.0 INTRODUCfION
. .
Under .the Defense E~oninental Restoration Pro~ it is the U.S. Navy's policy to .
address contamination at Navy installations in a manner consistent with the requirements
of the Comprehensive Environmental Response, Compensation, and Liability Act of 1980
(CERClA), as amended by the Superfund Amendments and Reauthorization Act of
1986. (SARA). The selected remedial action will comply with applicable or relevant and
appropriate requirements (ARARs) promulgated by the U.S. Environmental Protection
Agency (EPA) and the :Washington State Department of Ecology (Ecology).
. .
2.0 SITE NAME, LOCATION, AND DESCRIPTION
Naval Air Station (NAS) Whidbey Island is located 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 NAS Whidbey Island is divided into two facilities-the Seaplane Base
and Awt Field. The Seaplane Base is located in the northern portion of the island
adjacent to the c~ty of Oak Harbor. .operable Unit (OU) 4, the sole operable ~t at
Seaplane Base, consists of five study areas (Figure. 2): . .
.
.
Area 39: Auto Repair and Paint Shop
Area 41: Building 25 arid Building 26 Disposal Area
Area 44: Seaplane Base Nose Ha.D.caaI
Area 48: Seaplane Base Salvage Yard
Area 49: Seaplane Base Landfill
.
.
.
Portions of the Seaplane Base have been converted to base housing-related activities.
However, no actual housing is located in the immediate vicinity of the areas addressed in
this Record of Decision (ROD). Residential housing is located approximately 200 yards
to three-quarters of a mile away. The property adjacent to the areas addressed in this
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~.OO"
4S'rI1
~
~
o
o
o
Li:
(3
~
o
I
50
smA"
OF .
JUAN DE
FUCA
...
SCALE IN MD..ES
.ClEAN. eTO 0042
Figure 1 OPERABLE UNIT 4
COMPREHENSIVE Location Map NAS WHIDBEY. WA
LONG TERM RECORD OF DECISION
ENVIRONMENT At
ACTION NAVY
-------
BASE BOUNDARY
City 01
Oak Harbor
AREA 49
AREA 48
OAK
HARBOR
AREA 41
FORBES
POINT
MA YLOR POINT
CLEAN
COMPREHENSIVE
LONG TEAM
ENVIRONMENTAL
ACTION NAVY
LEGEND
- Area 01 Concern
Area 39 -
Area 41 .
Area 44 .
Area 48 .
Area 49 .
Auto Repair & Paint Shop
Building 25 & 26 Disposal Area
Nose Hangar'
Salvage Yard
landfill
SEAPLANE BASE
CRESCENT
HARBOR
Figure 2
Operable Unit 4 :
+
o
2000
4000
'.
SCALE IN FEET
, POLNELL
POINT
CTO 0042
OPERABLE UNIT 4
NAS WHIDBEY, WA
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SEAPLANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract .
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295 '
era 0042
Record of Decision
Date: 12/15/93
Page 4
ROD is used for administration offices, storage, and housing support facilities, a lawn
mower shop and gardening facility, boat and recreational vehicle storage, and a boat
marina. .
The Seaplane Base is located on a peninsula that was built up with material dredged
from Oak and Crescent Harbors in 1942. The original connection between Maylor Point
and the mainland of Whidbey Island was a narrow sand spit Most of the subsurface
soils present are from past dredging operations. The groundwater immediately below the.
site is. brackish; potable water is piped in from Anacortes. Surface runoff flows into Oak
Harbor or Crescent Harbor.
2.1
AREA 39: AUTO REPAIR AND PAINT SHOP
Area 39 was the location of a former auto repair and paint shop that was housed in
Building 49, located north of West Coral Avenue (Figure 3). From 1961 to 1965, an
: estimated 1,000 to 2,000 gallons of caustic radiator solvents were spilled on, th~ ground
northeast of Building 49. Approximately 2;000 gallons of radiator test tank water
containing traces of sealant, antifreeze, soldering compounds, and acid were reportedly
poured onto the ground south of Building 49 during the same period. From 1956 until
1982, wastewater from an BOO-gallon paint booth was reportedly discharged up to once a
week to the drainage ditch north of Building 49. The wastewater probably contained
paint residues. Currently, the building is used as a lawn mower shop and self-service
facility for base personnel.
2.2
AREA 41: BUILDING 25 AND BUILDING 26 DISPOSAL AREA
Area 41 is just w~st of Area 39 (Figure 4). It includes Building 25 (now demolished,
with concrete foundation intact), .Building 26, and the rock seawall located immediately
west of the buildings. These buildings were'used as paint shops in the 19405 and 1950s
and later housed the pest control shop in the 1960s. Personnel reportedly discharged
waste paint, thinners, solvents, and pesticides onto the seawall. No visible evidence of
these activities remains today. Building 26 is currently used for flammable materials
storage.
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_J
AREA 39
\
\ \
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./,.
// J'
I? /.
II I
/? I.
II , i
II "
If /1
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CLEAN
COMPREHENSIVE
. LONG TERM
ENVIRONMENTAL
ACTION NAVY
~
~
~
~
d
Agure 3
Area 39 . Auto Repair and Paint Shop
CT04MOMXUXI.ORW 16'11103
)
Iit#:;:~1 Approximate Area 01
;@:.::i@ Investigation
---
Dirt Road
[JjJ Building & Building No.
,-.-
'. ..' Building Foundation
-..-
DraInage Area
-25- Contour Llno
.J>----- Surface Water
"" ~ Flow Direction
)( Fence Une
) ( Culvert
~ Rock Seawall
1+1 0 100
.
SCAlE IN fEET
CTO 0042
OPERABLE UNIT 4
NAS WHIDBEY, WA
RECORD OF DECISION
-------
OAK
HARBOR
,\)~
c::::> ~
AREA 41
22
LI:G£:ND
I:, 'ii.~~l Approx. Area 01 Invesdgadon
SCALE IN FEET
~I
, \
\
\ ..""""
, . n~", - o\'f-'f\
, ~ /--1A8 '
( .. .. ot~(\
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"~/ 1 /'
"". / ""'"' .. ""
/ / J 1 ""../
./ / / I / '",," ~e.. "" ........
II / ,/"" ~
II II /'
/. I
, ,
..
---
DIrt Road
---
IJ[] BuildIng & BuildIng No.
~-- -- 3 Building Foundadon
-.....-
Dralnago Aroa
"Contour Uno
-25-
0--
Surface Water
Flow DIrection
x
Fence Una
) C Culvert
~ Rock Seawall
1*1
o
CLEAN
COMPREHENSIVE
LONG TERM
ENVIRONMENTAL
ACTION Nft)'V
CTOIMO!1SIG.04. '- 103
......-.---. .-,.. ......_... ..
eTO 0042
OPERABLE UNIT 4
NAS WHIDBEY. WA
RECORD OF DECISION
Figure 4 "
Area 41 . Buildings 25 and 26'DIsposai Area
GIS.
!ntI4J.1.pli
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SEAPLANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0042
Record of Decision
Date: 12/15/93
Page 7
2.3
AREA 44: SEAPLANE BASE NOSE HANGAR
The Nose Hangar was located at the northern end of a large paved apron area east of
Marina Drive (Figure 5). In the 19405 and 19505, the Nose Hangar was used as a service
and maintenance center for seaplanes. Operations included steam cleaning and washing,
fueling, lubricating, and parts cleaning. Numerous 1- to lOG-gallon aviation gas spills
were reported that may have been washed into Oak Harbor through the Area 44 storm
drain system. The Nose Hangar has since been demolished and only the foundation and
concrete apron remain. It is now used as a storage area for recreational boats and
vehicles.
,,'
2.4
AREAS 48 AND 49: SEAPLANE BASE SALVAGE YARD AND LANDFILL
. Areas 48 and 49 .were investigated and evaluated together in the Remedial Investigation
and Feasibility Study (RIfFS). They are located to the east of the main seaplane base
next to Crescent Harbor (see Figure 6). Area 48 was a salvage yard for the Seaplane
Base and was used from the 19405 until the late 19605 or early 19705. It was loeated
southeast of the intersection of Torpedo Road and East Pioneer Way. In the mid-1960s
there was a fire of flammable materials stored there, which reportedly resulted in
unknown quantities of solvents, thinners, strippers, and paints being spilled onto the
ground anci marsh. There is no visual evidence of the fire or storage yard activities.
'Area 49 was a 3- to 4-acre landfill that was ioeated farther east along Crescent Harbor.
. The landfill was used between 1945 and 1955 and reportedly all of the solid wzste from
Seaplane Base ope~tions was disposed of there in that period. Seaplane repair and
maintenance operations may have disposed of solvents, degreasers, paints, thinners, and
strippers at this landfill. No visi~le evidence can be found of the landfill. Both areas are
covered witb native grasses and are presently used for occasional recreational purposes.
There is a wetlands area just north of Areas 48 and 49. A 20-acre wastewater
stabilization lagoon is loeated in the wetlands, operated by the Qty of Oak Harbor. The
. outfall from the lagoon runs east of the landfill and extends some 3,000 feet offshore.
Historically, the wetland was a saltwater marsh. The beachline has been built up with
rip rap, cutting off the saltwater marsh. The wetland is hydrogeologically upgradient of
the site and is fed by off-site streams. The groundwater is brackish and is tidally
-------
14. .
rp--
OAK
HARBOR
Outflow Inlo
Oak Harbor
~\
!t@ti Approx. Area 01 Investigation
r:'" Building Foundation
[][I Building &. Building No.
-------.
Underground Drain Pipe
Conlour Una
Fence Une
AREA 44
~25-
)(
~ Rock Seawall .
[!) Catch Basin
OAK
HARBOR
MARINA
. 0 Sump
o Manhole
o
200
SCALE IN FEET
CLEAN
COMPREHENSIVE
LONG TERM.
ENVIRONMENTAL
ACTION NAW
Figure 5
Area 44 . Seaplane Nose Hangar
eTa 0042
OPERABLE UNIT 4
NAS WHIDBEY, WA
RECORD OF DECISION
CTOcMOII'$IG_OS.OP'
)
)
-------
)
..ili..
\
,
....,
,W,.\
,
"
. .. -..
,
,....%
I I
I I
, I
\
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)
..I%&lIon lagoon.
Il
[
.~
~ II
.\.Ik
~
~
.ili.
..ili..
~
SEAPLANE BASE
SALVAGE YARD
(AREA 48)
SEAPLANE BASE
LANDFILL
(AREA 49)
LEGEND
~
W~l.m
DefinWon 01 Area
-----
Dirt Road
-----
~f30~
~'\ "'~
. SC~ .
C~€ .
-25-
Contour Une
---.-
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@
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1.1
o
~o
SCALE IN FEET
CLEAN
COMPREHENSIVE
lONG TERM
ENVIRONMENTAL
ACTION NAVY
Figure 6
Area 48 . Salvage Yard and Area 49 . Base Landfill
eTO 0042
OPERABLE UNIT 4
NAS WHIDBEY, WA
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SEAPlANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 9042
Record of Decision
Date: 12/15/93
Page 10
influenced. . The ground slopes from the built-up area along the seawall toward East
Pioneer Way. There is no drainage nor are there culverts across the road. In Areas 48
and 49, rainwater p<;>nds during heavy rains, and eventually infiltrates into the ground.
. .
3.0 SITE HISTORY AND ENFORCEMENT ACfMTlES
NAS Whidbey Island was cOIIlITJissioned in 1942. The station was placed on reduced
operating status at the end of the war. In December 1949 a continuing program to
increase the capabilities of the station was begun. The station's current mission is to
maintain and operate Navy aircraft and aviation facilities and provide associated support.
Since the 1940s, operations at NAS Whidbey Island have generated a variety of .
hazardous wastes. These wastes were disposed of with practices that were considered
acceptable at the time. '.
In response to the requirements of CERClA, the U.S. Department of Defense (DoD)
established the Installation Restoration Program. (IRP). From 1980 until early 1987, the
. Navy's program was called the Navy Assessment and Control of Installation Pollutants
(NACIP) program. In spring 1988, the Navy (through OPNA VINST 5090.1) adopted
EP A terminology and procedures and dropped those of NACIP. Consequently, all
continuing studies at NAS Whidbey Island and other Navy facilities follow EPA
guidelines ~stablished for National Priorities List (NPL) sites.
. Responsibility for the impleme.ntation and administration of the IRPhas been assigned
to the Naval Facilities Engineering Command (NAVFACENGCOM). The Engineering
. Field Activity, Northwest (EF A NW), a part of NA VF ACENGCOM, has responsibility
for investigations at NAS Whidbey Island and other Navy installations in the Pacific
Northwest and Alaska.
The Navy conducted an Initial Assessment Study (IAS) at NAS Whidbey Island under
the NACIP program. The lAS, which consisted primarily of a records search, was
completed in September 1984. A more detailed report, the NAS Whidbey Island
Current Situation Report (CSR), was completed by the Navy in January 1988. Data on
shellfish and marine se'diment colleCted from the Seaplane Base were presented in the
CSR.
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SEAPLANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract. No. N62474-89-D-9295
era 0042
Record of Decision
Date: 12/15/93
Page 11
While the CSR was being prepared, EPA Region 10 performed preliminary assessments
at NAS Whidbey Island to evaluate risks to public health and the environment. EP A
used the Hazard Ranking System (HRS) to evaluate Seaplane Base and Ault Field.
In late 1985, EPA proposed that Ault Field and the Seaplane Base be nominated to the
NPL. In February 1990, these sites were officially listed on the NPL, based on several
factors: '
.
The number of waste disposal and spill sites discovered
.
The types and quantities of hazardous constituents used and disposed of at
the sites (including petroleum products, solvents, paints, thinners, jet fuel,
pesticides, and other wastes) ,
.
Potential impacts on domestic wells and local shellfish beds
In response to tbe NPL designation, the Navy, EPA, and Ecology entered into 'a Federal
Facilities Interagency'Agreement (FFA) in October 1990. The FFA established a
procedural framework and schedule for developing, implementing,' and monitoring
appropriate response actions at NAS Wbidbey Island.
Following CERCIA and SARA guidelines, various sites and areas at NAS Wbidbey
Island were later grouped into "operable units." The term "operable unit" (OU) is used
to designate specific areas undergoing RIfFS investigations. The five areas at the
Seaplane Base (Areas 39, 41, 44, 48 and 49) were collectively' identified as OU 4. The .
purpose of the RIfFS was to characteriZe the site, deterlnine the nature and extent of
contamination, assess human and ecological risks, and evaluate remedial alternatives. .
4.0 ~OMMUNITY RELATIONS
In accordance with Section 117(a) of CERCLA,.as amended by SARA, the Proposed
Plan for au 4 was released to the public via the Whidbey News Tunes on August 14,
1993. Public comments have been considered in the remedy selection process.
Community relations for the Seaplane Base au 4 investigation included the following
activities:
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SEAP~E BASE, OPERABLE UNIT 4
U.s. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0042
Record of Decision
Date: U/15/93
Page 12
.
Creation of a C()mmunity Relations Plan (finalized January 10, 1992)
.
Quarterly Technical Review Committee meetings with representatives from
the public and from other governmental agencies
.
Issuance of the final Proposed Plan (issued on August 9, 1993)
.
Public ,meeting ~o present the, final Proposed Plan (held on September 1,
1993) .
.
Issuance of a fact sheet summarizing the Record of Decision, concurrent
with the signing of this document
Information repositories to make available details of OU 4 RI/FS activities were
established at the following locations:
Oak Harbor' library .
7030 70th N.E.
Oak Harbor, Washington, 98278
Phone: (206) 675-5115
Sno-Isle Regional Library System
Coupeville Libraxy
788 N.W. Alexander
Coupeville, Washington. 98239
Phone: (206) ,678-4911 "
For anyone with 'access to NAS Whidbey Island:
Naval Air Station Whidbey Island
Station Library .
1115 West Lexington Street
Oak Harbor, Washington 98278
Phone: . (206) 257-2702
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SEAPLANE BASE, OPERABLE UNIT 4
U.s. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
era 0042
Record of Decision
Date: 12/15/93
Page 13
The administrative record is located at:
Engineering Field Activity, Northwest
Naval Facilities Engineering Command
1040 NE Hostmark Street
Olympic Place 1
Poulsbo, Washington 98370
Phone: (206) 396-5984
The mailing address for the Administrative Record is:
Engineering Field Activity, Northwest
Naval Facilities Engineering Command
3505 N. W. Anderson Hill Road
Silverdale, Washington 98383
Noti~e of the availability of the Proposed Plan, plus notice of a public meeting.on the
Proposed Plan and of the public com.m~nt period, were published in the Whidbey News
Times on August 14, 1993, and the plan was distributed to the public on August 15, 1993.
The public comment period was from August 16, 1993, to September 15, 1993. A public
meeting to present'the Proposed Plan to concerned citizens was held at the Chief Petty
Officer's Club on Ault Field Road on September 1, 1993, at 7:00 pm. No citizens
attended, but .representatives of the Navy, EP A, and Ecology were present
No comments were received by the Navy at that meeting concerning the Proposed Plan, .
but two letterS were submitted on the Proposed Plan and are presented in the
"Responsiveness Summa..""Y" (Attachment A) appended to this Record of Decision.
5.0 SCOPE ~ ROLE OF OPERABLE UNITS
NAS Whidbey Island comprises tWo main facilities, Ault Field and the Seaplane Base.
. These two facilities are geographically separated. There are three operable units at Ault
Field (OU 1, OU 2, and OU 3) and one operable unit at the Seaplane Base (OU 4).
This Record of Decision addresses OU 4 at the Seaplane Base. The operable units at .
Ault Field are addressed separately and not in this Record of Decision.
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SEAPlANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract'
Engineering Field Activily, Northwest
Contract No. N62474-89-D-9295
ero 0042
Record of Decision
Date: 12/15/93
Page 14
The proposed remedial actions at the Seaplane Base address surface soil contamination
detected above established state and federal health-based and regulatory levels. Surface
soils at Area 39, 41, 44, and 48, and sediments in the storm drain at Area 44 are the only
environmental media that required remedial action.
The results of the RI indicate, that lead, arsenic, chromium, polycyclic aromatic
hydrocarbons (PARs), and pesticides are the contaminants of concern at Areas 39, 41,
44, and 48. Some of these compou~ds are present only in discrete locations. Th~ Navy
will undertake removal actions in the areas listed above. . ,
The proposed remedial actions of soil removal and dispos3.I address the only threat to
human health and the environment at OU 4 and fulfill the Navy's goal of remediating
this operable unit to the fullest extent practicable. '
6.0 SUMMARY OF SITE CHARACTERISTICS
This section presentS a summary of site conditions, including a d~cussion of the geologic'
and hydrogeologic characteristics and the nature and extent of contaminants.
6.1
SITE GEOLOGY, HYDROGEOLOGY, AND SURFACE WATER HYDROLOGY
Whidbey Island lies within the Puget .Lowland, a topographic and structural depression
, between the Olympic Mountains and the Cascade Range. Previous, mvestigations report
- that the geologic units on Whidb~y Island consist of w-pe~eability
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SEAPlANE BASE, OPERABLE UNIT 4
U .5. Navy CLEAN Contrad
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
era 0042
Record of Decision
Date: 12/15/93
Page 15
Cretaceous or Tertiary bedrock (older than 30 million years) underlies the
unconsolidated Quaternary deposits. The Everson and Vashon units of the Fraser
glaciation, post-glacial sediment, and artificial fill make up most of the surface and near-
surface soil underlying the Seaplane Base. Recent organic-rich silt and clay,' as well as
artificial fill consisting of dredged marine sediment, cover the Maylor Peninsula. The
narrow northern ,part of the peninsula was originally a neck of land connecting Wbidbey
Island with Maylor Point; it was filled in the mid-1940s to construct the buildings and
facilities of the Seaplane Base. The fill material consists of sediment dredged ftom the
surrounding harbors. The stratigraphy over the ,remainder of the base generally consists
of glaciomarine drift overlying Vashon till and advance outwash. The wetland north of
Areas 48 and 49 contains organic-rich silt and clay.
The results of the RI showed that ground~ater beneath Areas 39, 41, and 44 generally
flows west toward Oak Harbor at a gradient ranging from 0.011 to 0.012 (ft/ft)
(Figure 7). The direction of groundwater flow in Areas 48 and 49, located north of
Cr~scent Harbor, is variable owing to tidal influence. Some water level measurements
indicated that the groundwater flow direction is to the northeast. However, continuous
water level measurements over a tidal cycle show that the net groundwater flow direction
was south toward Crescent Harbor (Figure 8)..
The hydrogeologic investigation revealed that a near-surface, unconfined aquifer exists in
Areas 39. 41, 44, and 48 and 49. The deepest monitoring well drilled during the RI/FS
was to a depth of 67 feet below ground surface (bgs) at Areas 48 and 49. No confining
units were encoUntered in this well. The unconfined aquifer extends at least to, the
depth of the bottom of this boring.
Groundwater at the Seaplane Base is not considered a potential drinking water 'source
because the groundwater in this area is brackish. Surface runoff from the Seaplane Base
discharges into either Crescent Harbor or Oak Harbor. Surface soils at the Seaplane
Base are generally low permeability silty sand, accounting for common ponding in lower-
relief areas during high rainfall events and throughout the winter. This is especially
common in Areas 39,48, and 49.
Oak Harbor is the evennial surface water discharge site for Areas 39, 41, and 44.
Surface water drainage for Area 39 is influenced by a lOO-foot-high hill a few hundred
feet south of the area. This topographic high directs surface water across Area 39 to a
swale and a drainage ditch, which trend in a southwesterly direction. Surface water
-------
\.
.~
en
\!l
OAK.
, . HARBOR. .
- - - - Draina;e Dilch
)( Fm Ln
. ? -- -- -- InfernId COdDur
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o
.
400
,
s:ALE IN fEET
CLEAN ero 0042
Rgure 7 OPERABlE UNIT ..
COMPREHENSIVE Areas 39, 41, and 44 Potentiometric Surface Contour Map . NAS WHIDBEY. WA
LONG TERM Aprit 14, 1992 RECORD OF DECISION
ENVIRONMENTAL
I ACTION NAVY
-------
. ----, )
Wastowater sra.
)
Jon Lagoon
..lib
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LEGEND
+ Monllorlng Woll
(7.9027) Groundwater Elevation
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(5.7406l
. O~
. . ~ \,,\f>.f\6
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-.--
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-10- Elevalion Contour Une
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.~. Wedand
-2.40- Groundwater Contour Une
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~
?------
Groundwater Flow Dlreclion
Inferred Contour
All Elevalions MLLW
+.1
o
.
200
400
.
SCALE IN FEET
CLEAN
COMPREHENSIVE
. LONG TERM
ENVIRONMENTAL
ACTION NAVY
CT042\Roo.FIQ.08.DRW I«WIt'"
Agure 8 .
Area 48/49 Tidal Study Net FloW Direction'
Source: Serfes, 1991
CTO 0042
OPERABLE UNIT 4
NAS WHIDBEY, WA
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SEAPLANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ere 0042
Record of Decision
Date: 12/15/93
Page 18
following the swale drains to a nearly level field west of the area, where it infiltrates into
the ground. The ditch extends under a gravel road and discharges directly into Oak
Harbor.
In Area 41, most of the surface water flows across paved areas and into storm drains
before discharging into Oak Harbor. Elsewhere, surface water drains across nearly level,
unpaved areas that surround Building 26, down the rip rap seawall embankment, and into
the Qak Harbor. ' "
Area 44 is a paved storage area; one sump and' four catch basins are located in the
northern part of the area. A drain pipe connects the sumps and the outfall of the drain
is located directly west in the riprap bordering Oak Harbor.
Areas 48 and 49 lie on fairly level ground, with Crescent Harbor to the south and
wetlands to the north. The topography slopes gently toward the wetlands. However, the
surface water flow to the north is impeded by a slightly elevated road bed (East Pioneer
Way), which prohibits direct discharge into the wetlands. Surface water in the wetlands
is recharged mostly by precipitation and from a natural spring located approximately 2
miles north of the wetlands. Surface water in, the wetlands area was not present at three
of the four planned sampling locations during the Phase I RI field' program.
There is no evidence (i.e., ditches or drainage swales) of any surface water flow in Areas
48 and 49. Surface water does not enter Crescent Harbor from Areas 48 and 49 because
of the elevated' dike bordering the harbor. '
" '
A large wetland area (approximately 250 'acres) lies to the north of Areas 48 and 49.
The wetland is an old saltwater marsh that is hydrologically upgradient of OU 4. It is a
non-tidal, freshwater wetland, seasonally flooded and dominated 'by emergent vegetation.
The vegetation consists of grasses, scrub and shrub vegetation, and trees in early and
middle stages of succession. A municipal wastewater lagoon system occupies about 24
acres in the middle of the wetland. A surface drainage enters the wetland from the
north and drains through a tidegate just east of the road access to the wastewater lagoon.
6.2
NATURE AND EXTENT OF CONTAMINANTS
Surface and subsurface soil, marine sediment, groundwater, and surface water samples
were analyzed for volatile org~~. compounds (VOCS), semivolatile organic compounds
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SEAPLANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 00"42
Record of Decision
Date: 12/15/93
Page 19
(SVOCs), and target analyte list (TAL) inorganics. In Areas 39, 41, 48, and 49, soil
samples were also analyzed for chlorinated pesticides and polychlorinated biphenyls
(PCBs). In Area 41, where former activities included a pest control shop, additional
analyses for organophosphorus pesticides and chlorinated herbicides ~ere performed.
Marine tissue samples (mussels) were analyzed for SVOCs, chlorinated pesticides, PCBs,
chlorinated herbicides, and inorganics adjacent to Areas 41, 44, 48 and 49. Background
concentration levels for inorganics were established from soil, groundwater, marine
sediment, and mussel tissue samples collected at OU 4 outside the 'areas ,of suspected,
contamination for all ni~dia.
The following paragraphs describe the nature and extent of contamination for chemicals
of concern (COCs) identified in soil, groundwater, marine sediment, mussel tissue,
freshwater sediment, and surface water for each area. COCs are defined as chemicals
that exceed human health and ecological risk threshold concentrations based on federal
or state criter~a. Inorganic chemicals that were at or below background concentrations
were not considered a COc., T~ble 1 lists the COCS for soil. '
6.2.1
Soil
.
Area 39
Surface soils and sediments in Area 39 had concentrations of chromium, lead, polycyclic
aromatic hydrocarbons (PAHs), and 4,4'-DDE and 4,4'-DDD (pesticides) that-exceeded
background concentrations and risk-based criteria. Lead and P AHs were the most
widespread COCs. They were detected northeast of Building 49 and in the southern
swale north of the building. ' The pesticide concentrations were detected in the drainage
ditch next to a road culvert. Figure 9 shows theselocatioDS. The estimated volume of
soil containing COCs is approximately 260 cubic yards.
The COCS have not migrated off site or infiltrated into groundwater. They are detected
, only in the upper 1 or 2 feet of the soil column.
.
Area 41
At Area 41, pesticides (4,4'-DDE and 4,4'-DDT) were detected above state cleanup
levels in two localized shallow areas around the foundation of Building 25. Figure 10
shows these areas. The estimated volume of contaminated soil containing contaminants
of concern is 2 to 5 cubic yards.
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SEAPLANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0042
Working Copy Record of Decision
Date: UI15/93
Page 20
Table 1
Chemicals of Concern in Surface Soil of Seaplane Base
39 Arsenic 1.4 8.5 4.02 17/40 ~.7
Chromium 18.3 523 115.10 21/54 43.3
Lead 2.9 736 233.14 22/44 26.5
Benzo( a)anthracene 0.017 2.6 0.434 10/49
Benzo( a)pyrene 0.022 0.~5 0.205 7/49
Benzo(b )fluoranthene 0.043 0.43 0.169 5/48
Benzo(k)fluoranthene 0.046 2.3 0.47 8/49
Chrysene 0.014 0.9 0.233 9/49
Indeno( 1.2,3-cd)pyrene 0.012 0.23 0.102 5/49
4,4'-DDD 0.0046 4.0 0.677 7/8
4,4'-DDE 0.00078 4.8 0.528 12/U
41 Lead 3 298 76.46 11/21 26.5
4,4'-DDE 0.00057 4.1 0.50 13/21
4,4'-DDT 0.0038 41.0 3.43 14/20
44 Arsenic 1.7 (surface 25.7 (surface 7.17 . 9/12 2.7
soil) soil)
21 48.3 (manhole) 48.3 1/1 2.7
(manhole)
Lead 3,625 (sump) 3,625 (sump) 3,625 1/1 26.5
3,370 3,370 3,370 1/1 26.5
(manhole) . (manhole)
14.5 (catch 2,180 (catch 2,180 1/2 26.5
basin) basin)
6.1 (surface 3,150 (surface 781 6/12 26.5
. soil) soil)
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SEAPlANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0042
Working Copy Record of Decision
Date: 12/15/93
Page 21
Table 1 (Continued)
Chemicals of Concern in Surface Soil of Seaplane Base
I_~.-
48 Benzo( a) anthracene 0.01 1.7 0.392 6/41
and Benzo( a)pyrene 0.006 2.2 0.37 8/41
49 . Benzo(b )fluoranthene 0.029 4.9 0.75 9/41
Benzo(k)fluoranthene 0:033 4.9 0.811 7/40
Chrysene 0.018 2.0 0.33 9/41
Dibenzo( a,h)anthracene 0.054 0.28 0.131 3/41
Indeno( 1,2,3-cd)pyrene 0.062 0.93 0.284 5/41
aDetectionsjnumber of samples taken
- = Background levels were Dot. determined for organic chemicals.
Note: . . .' . .
Chemicais of concern were Identified as those chemicals exceeding federal and state threshold concentrations.
-------
cc
o
~
~
~
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o
CLEAN
COMPREHENSIVE
LONG TERM
ENVIRONMENTAL
ACTIO.' ,
o
Sample location
cac Detected
-------
Exceeds Risk Standards
Extent ollnv9Stigalion
Din Road
o
~ Area 01 Concem
Q[J Building & Building No.
i - - -. Building Foundalion
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)(
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) ( Culvert
~ Rock Seawall
1+1
o
100
SCALE IN FEET
. Figure 9 .
Area 39 . Spatial Distribution of COCs.Detected In Surface Soli
C10 0042
OPERABLE UNIT 4
NAS WHIDBEY, WA
-------
LEGEND
o Mussel Sample location
o Sample location
€a cae Detected
--
Extent 01 Investigation .
. ~~ Area 01 Concern
-------
DIrt Road
[![) Building & Building No.
-------
-..-
Drainage Area
25 - Contour Une
. Surfaoo Water
~ Flow Direction
)( Fence Une
) ( Culvert
~ Rock Seawall
~I,'
SCALE IN FEET
CLEAN
COMPREHENSIVE
LONG-TERM
ENVIRONMENTAL
ACTION NAW
OAK
HARBOR
""I
I
o
o
22
o
0 0
0
o 0
o
o
o
o
.. . Agure 10
Area 41 . Spatial Distribution of COCs Detected In Surface Soli and Marine Sediments
CTO 0042
OPERABLE UNIT 4
NAS WHIDBEV, WA
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SEAPLANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
era 0042
Record of Decision
Date: 12/15/93
Page 24
These COCs were not detected at depth in the soil column or in the groundwater.
Pesticides were detected in the marine sediments, but only in buried sediments at a
depth greater than 4 to 8 inches, below the biologically active zone. None were detected
in mussel tissue.
.
Area 44
The sediments in the storm drain system (catch basin, sump, and a manhole) contained
high levels of lead and arsenic. Surface soils adjacent to the sump at the north edge of
the concrete apron also contain lead and arsenic. Figure 11 shows the locations of these
areas. These COCs were found only in the surface soils and have not migrated
downward in the soil column, nor were they detected in the groundwater. The storm
drain discharges into Oak Harbor; however, no concentration exceeding background
. levels of lead or arsenic was detected in the sediments near the outfall. Therefore,
transport to the marine environment was not substantiated. The volume of soil and
storm drain sediments containing elevated levels of lead and arsenic' is estimated to be
20 to 30 cubic yards.
.
Areas 48 and 49
The principal COCS detected in Area 48 were P AHs at the salvage yard (Area 48),
where a fire occurred in the 1960s. No COCs were detected above federal or state
standards in Area 49. PAHs are not highly mobile in the soil column; however, a
number of P AHs were. dete~ted in the groundwater. . P AHs were detected in one marine
sediment sample (0 to 4-inch depth).
The soils at Area 48 that contain the elevated concentrations of P AHs are shown in
Figure 12. Th~ volume of contaminated soil to be removed is estimated to be 1,000
cubic yards.
6.2.2 Groundwater
Inorganic and organic chemicals were detected in groundwater at all areas (Table 2).
The groundwater is not considered potable. Although organic and inorganic analytes
were detected in groundwater in all areas, the potential for exposure to contaminants in
groundwater near the shore is low. The groundwater is not considered potable because
coastal waterbearing strata on Whidbey Island are at a high risk of saltwater intrusion,
-------
~
~
14
OAK
HARBOR
o
LEGEND
o
o
ED
.
o
--
'I.~
Muml Sample Location'
Samplo locadon
COC Detoctod
Exceeds Risk Standards
Extant ollnvosdgadon
o
.JI Aloa 01 Concern
~ Building & Building No.
2S
X
OAK
HARBOR
MARINA
+
CLEAN
COMPREHENSIVE
lONG TEAM
ENVIRONMENTAL
ACTION NAVY -
Figure 11
Area 44 . Spatial Distribution 01 COCs Detected In Surface Solis,
Storm Drain Sediments, and Marine Sediments
Conlour Un~
Fence Uno
~ Rock Soawall
o
100
SCAlE IN FEET
CTO 0042
OPERABLE UNIT 4
NAS WHIDBEY, WA
-------
\
.
.w. ~ .w,. .w,. - ~
.
.,
. -,
~ ..w. ~ . ..J ~
J I
Wastewater Stabilization .l.agoon
IlL.
I
.ill.
.,
\
\\
\\
"
"
"
"
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"
"
"
"
"
..
~
o
o
f\eOf\
~, \'\~
€.50€.
0~
..
CLEAN
COMPREHENSIVE
LONG TERM
ENVIRONMFMT ~l
ACTlO~'
. Agure 12
Area 48149 . Spatial Distribution of COCs Detected In Surface Soli and Marine Sediments
c::I
LEGEND
o
o
E9
Mussel Sample location
Sample location
coe Detected
--
Area Boundar/os
(11*1 Area of Concern
------- Dirt Road
-----.-
Building Foundation
-..- Drainage Area
25 Contour Une
< 'Surface Water
Flow Direction
-)(- Fence line
@ Wetland
+ 0 200 400
. .
SCALE IN FEET
cro 0042
OPERABLE UNIT 4
NAS WHIDBEY, WA
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41
44
48
and
49
Working Copy Record of Decision
Date: U/15/93
Page 27
Table 2
Chemicals of Concern in Groundwater of Seaplane Base
1., 1,2- Trichloroethane 5.87 5.87 5.87
1,2-Dicbloroethane 274 274 274
Chloromethane 13.9 13.9 13.9
Benzo( a) anthracene 5.5 5.5 55
Benzo(k)fluoranthene 5.2 5.2 5.2
Chrysene 6.0 8.2 7.1
Indeno(1.,2,3-cd)pyrene 33.0 33.0 33.0
Aldrin 0.01 0.01 0.01
Dieldrin 0.02 0.02 0.02
Heptachlor 0.44 0.44 0.44
aDetections/number of samples taken
- = Background levels were not determined for organic chemicals.
.---.
39 Arsenic 2 11.9 53 3/4 2.0
Manganese 113 889 468 4/4 16.7
Chloromethane 4.42 4.42 4.42 1/2 -
Tetrachloroethene 1.87 1.87 1.87 1/3 -
1,3-Dichloropropane 1.04 1.04 1.04 1/3 -
Carbon tetrachloride 0.55 0.55 0.55 1/3 -
Benzo(k)fluoranthene 6.5 6.5 6.5 1/4 -
Aldrin 0.03 0.03 0.03 1/1 -
Manganese 1,610 2,630 2,120 2/2 16.7
l,2-Dichloroethane 5.8 5.8 5.8 1/1 -
l,3-Dichloropropene 13.8 13.8 13.8 1/1 -
Vinyl chloride 4.0 4.0 4.0 1/1 -
Benzo(k)fluoranthene 7.4 7.4 7.4 1/2 ,-
Aldrin 0.Ql 0.01 0.01 1/1 -
Manganese 114 2[,9 176 3/3 16.7
1,1,2-Trichloroethane 0.96 0.96 0.96 1/1 -
Chloromethane 36.9 36.9 36.9 1/2 -
Methylene c!lloride 10.0 10.0 10.0 1/1 -
Arsenic 2.1 2.5 2.3 2/3 2.0
1/5 -
1/4 -
1/6 -
1/9 -
1/9 -
2/9 -
1/1 -
2/2 -
1/1 -
1/11 -
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which would prevent it from being used as a potable water supply. Salinity profiles
developed for the monitoring wells in the areas of concern verify this is an area of high
risk for salt water intrusion. Also, Island County Department of Health regulations
prohibit the development of private or public drinking water wells within 100 feet of the
mean high tide level.
6.2.3 Marine Sediment and Mussel Tissue
.
Marine Sediment
Marine sediment was collected from 11 stations in Area 41 (Figure 10), 4 stations from
Area 44 (see Figure 11), and 10 stations from Areas 48 and 49 (see Figure 12). .
Sediment samples were collected from three depths at each station (0 to 4 inches, 4 to
20 inches, and 20 to 36 inches).
A summary of eacs dete~ted in marine sediments is presented in Table 3 and 4. Table
3 compares the. number of COCs detected above the sediment quality standard$ in the
surface sediments (0 to 4 inches) with those in the subsurface sediments (4 to 36 inches).
Beta-BHC, delta-BHC, and fluoranthene were the only identified caCs found in the
. surficial sediments where the greatest exposure to aquatic organisms occurs. The
number of cae detections above the state standards is significantly higher in the
subsurface sediments.
Table 4 compares the carbon-normalized values of the caCs detected in the surface
(top), mid, and bottom sediment samples taken at each sampling station with the
sediment. management standard Cleanup levels. All..of the surface and mid-depth sample
cac concentrations were below the cleanup levels. At only three stations, one off of
Area 44 and two off of Areas 48 and 49, were cae detections above the state cleanup
value. These three detections (highlighted with shading in Table 4) occurred in the
bottom samples taken at 1.5- to 3-foot depth.
.
Mussel Tissue
Mussel tissue was collected from five stations in Area 41, three stations in Area 44, and
three stations in Areas 48 and 49. Mussel tissue sampling stations are shown in Figure
10 for Area 41, Figure 11 for Area 44, and Figure 12 for Areas 48 and 49.
Arsenic was the only cac detected in mussel tissue.
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Table 3
Comparison of Chemicals of Concern Detected in Surface and Subsurface Marine Sediment
in Areas 41, 44, 48, and 49 (mgjkg)
--~-~-
41 gamma-BHC - - - 0/11 0.0005 0.0005 0.0005 1/21
delta-BHC 0.0021 0.0021 0.0021 1/11 - - - 0/21
4,4'-000 0.00045 0.0093 0.0038 4/11 0.00062 0.08 0.017 12/21
4,4'.00T 0.002~ 0.0042 0.0036 2/11 0.00073 0.052 om5 10/22
OJ-n-octyl phthalate 0.023 0.037 0.027 5/12 0.023 0.23 0.066 11/16
Endosulfan II - - - 0/11 0.00087 0.00087 0.00087 1/21
Auoranthene 0.02 0.22 0.093 3/11 0.016 0.150 0.085 6/15
Heptachlor epoxide - - - 0/11 0.0011 0.0011 0.0011 1/21
Bis(2-ethylhcxyl) phthalate 0.62 0.62 0.62 1/4 0.21 0.75 0.48 2/7
Aroclor-1254 - - - 0/9 0.54' 0.54 0.54 1/9
beta-BIIC 0.00057 0.00057 0.00057 1/9 - - - 0/10
delta-BHC 0.00068 0.00091 0.0008 2/10 0.00082 0.0021 0.0015 2/10
gamma-Chlordane - - - 0/9 0.0027 0.0027 0.0027 1/9
Oi-n-octyl phthalate - - - 0/7 0.36 0.36 0.36: 1/8
Bis(2-ethylhexyl) phthalate - - - 0/7 0.59 0.59 0.59 1/8
44
48 and
49
'Means were calculated using detected concentrations only.
bFrequency of detection Is defined as the number of samples with detected concentrations of u chemical/tollil numher ur sum pies.
- = COCs not detected in this stratum. .
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Table 4
Marine Sediment Risk Summary
-
.41-MS-l Bis(2-ethylhexyl) phthalate 23.0 27.6 ND 78
DDD 0.3 0.4 1.4 NA
DDT !\'D 0.4 6.3 :'>JA
Heptachlor 0.4 :\'0 0.5 :-.IA
Methoxychlor ND :\"O 0.5 ~A
41-MS-2 Di-n-buty! phthalate ND 39.2 ~'D 1.700
DDD 0.9 1.5 ND NA
DDT ND 13.3 0.7 NA
Endosulfan n ND 0.6 ND NA
41-MS-3 Bis(2-ethylheX)1) phthalate 13.2 ND ND 78
Di-n-butyl phthalate 9.0 "D 43.5 "1.700
DDD 1.2 41.8 9.8 NA
DDE 0.1 3.5 0.9 NA
DDT 0.6 9.9 2.1 2':A
41-MS-4 2-Methylnaphthalene ND 10.0 1.9 64
Anthracene ND NO 2.8 1.200
Phenanthrene ND 36.5 3.2 480
8enzo(a)anthraccne 33.0 27.4 ND 270
8enzo(a)pyrcne 14.7 NO ND 210
Total 8enzofluoranthenes 68.2 157.1 18.6 450
Clrysene 32.6 39.3 ND 460
Di-n-butyl pbthalate 5.5 31.1 15.5 1.700
Di-n-ocryl phthalate 13.6 100.5 8.7 4,500
Auoranthene 47.6 91.3 10.7 1,200
Pyrcne 36.6 46.6 9.9 1,400
Phenol ND NO 62.0" 1,200"
DDD ND 15.5 2.S NA
DDE ND NO 0.5 NA
DDT ND 23.7 8.2 NA
Endrin aldehyde ND 1.8 ND NA
Heptachlor cpoxide ND 1.0 ND NA
,
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. Table 4 (Continued)
Marine Sediment Risk Summary
r!JI " _I
41-MS-5 Phenanthrene NO 4.5 ND 480
Benzo(a)anthraccne 8.0 ND 22.4 270
Bis(2-ethylhexyl) phthalate J'I.'D 34.5 ND 78
Total Benzofluoranthenes 33.3 ND 138.8 450
Quysene 142 ND 44.8 460
Di-n-but}1 phthalate 13.6 16.7 19.2 1.700
Di-n-octyl phthalate 16.0 34.5 103.0 4.500
Fluonnthene 12.3 41.2 30.4 1.200
Pyrcne 13.6 8.2 24.6 1.400
Phenol 50.0" 50.0" ND 1.200"
DDD 2.8 4.9 1.8 NA
DDE ND 0.5 0.7 NA
DDT 1.8 1.8 1.8 :-:A
41-M~ Total Benzofluoranthenes 203.0 ND ND 450
Chrysene 78.4 NO ND 460
Fluoranthene 203.0 :-11) ND 1.200
Pyrene 129.2 :-11) NO 1.400
DDD NO 1.7 3.2 NA
DDE NO 0.6 0.7 NA
Pqenanth1'Cne 38.7 ND ND 480 .
Benzo(a)pyrene 28.6 ND ND 210
Di-n-octyi phthalate 22.1 ND ND 4,soo
2-Metbylnaphthalene NO NO 10.6 64
Naphthalene ND ND 9.7 170
Pbenol NO ND 200.0" 1.200"
41-MS-7 Pbenanthrene ND 11.1 29.5 480
Total Benzof1uorantbenes NO 35.0 100.1 450
Chrysene NO ND 65.2 460
Di-n-butyl phthalate 17.4 19.1 6.2 1,700
Di-n-octyi phthalate ND 413 15.8 4.500
Auoranthcne ND 25.4 102.9 1,200
Pyrene ND 36.6 85.7 1.400
DDD ND 2.2 ND NA
gamma-BHC ND 0.8 ND NA
41-MS-8 delta-BHC 2.1 ND ND NA
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Table 4 (Continued)
Marine Sediment Risk Summary
-
41-MS-9 Di-n-butyl phthalate NO !\o'D 7.1 1.700. .
Di-n-octyl phthalate NO 17.3 ND 4.500
Phenol 74J1 ~O 48.0" 1.200
. gamma-Chlordane NO NO <0.1 NA
Heptachlor NO :\'D 0.2 NA
4 I-MS-IO Di-n-butyl phthalate NO 10.2 NO 1.700
Di-n-octyl phthalate 15.2 43.6 ND 4,500
Phenol- 32.0 16.0 NO 1.200
Heptachlor 0.4 ~'O NO NA
41-MS-I I Oi-n-octyl phthalate 11.8 17.2 16.6 4.500
Diethyl phthalate 9.2 :\'0 ND 110
Pyrene ND :\'O 12.8 1.400
Phenol 38.0" ;"'0 NO 1.200"
gamma~ordane !\'D 1'<0 0.4 NA
Heptachlor NO 0.1 0.5 NA
44-MS-1 Total Bcnzofluoranthenes NO 2S2. 7 NO 4SO
44-MS-2 No Detections
44-MS-3 Total Benzofluoranthenes 5.8 ;"'0 NO 450
Bis(2-ethylhexyl) phthalate 17.9 25.6 ::~Illf~~t:ttl: 78
Chrysene 7.3 NO ND 460
Di-n-octyl phthalate 35.8 NO NO 4,500
Pyrene NO 19.5 7.7 1.400
44-MS-4 Phenol 72.0" NO NO 1.200"
48/49-MS-l Bis(2-ethytbexyl) phthalate NO NO !~@i,Mi,~f@m 78
Di-n-octyl phthalate NO ND 351.9 4.500
48/49-MS-2 delta-BHC NO 6.5 1.6 NA
Dieldrin NO 1.5 NO NA
Endosulfan II NO 1.9 NO. NA
48/49-MS-3 No Detections
48/49-MS-4 No Detections
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Table 4 (Continued)
Marine Sediment Risk Summary
. - - -
48/49-MS-S delta-BHC ND ND 1.9 NA
gamma-Cblordane ND NO 2.S NA
PCB-l2S4 ND NO ,m:tII:iY'i:tt::t 65
48/49-MS-6 2-Methylnaphthalene NO NO 31.4 64
Naphthalene ND :\'O 29.0 170
Phenanthrene 30.3 1\'0 NO 480
Benzo( a)pyrene 22.4 NO NO 210
Total Benzofiuoranthenes 158.8 1\'0 NO 450
Chrysene 61.4 NO NO 460
Di-n-octyl phthalate 17.3 ND NO ;4,500
Phenol ND ND 200.0" 1,200'
Di-~-butyl phthalate 43.3 ND 229,5 1,700
Auoranthene 158.8 NO NO 1.200
Pyrene 101.1 NO NO 1.400
48/49-MS-7 Di-n-butyl phthalate 74.1 ND NO 1.700
48/49-MS-S Di-n-butyl phthalate 77.6 91.6 ND 1,700
beta-BHC 0.3 ND NO NA
delta-BHC 0.4 ND NO NA
Endosulfan II 2.3 ;'IID NO NA
Endosulfan sulfate 0.7 ND ND NA
48/49-MS-9 delta-BHC ND 0.6 NO NA
Dieldrin 0.4 NO NO NA
48/49-MS-I0 Di-n-butyl phthalate ND 62.S 45.6 1.700
delta-BHC 0.6 ND NO NA
'Phenol concennations presented in pg/kg dry weight
. Notes:
NO = Not detected
NA = Not available
OC = Normalized to organic carbon
SMS '" Washington State Sediment Management Standards. Chapter 173-204 WAC
CSL = Oeanup Screening Levels from SMS Table m
Shaded values represent exceedance of SMS Table m Sediment Oeanup Levels.
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6.2.4 Wetland Sediments and Surface Water
Freshwater sediment was collected from four stations on the southern border of the
wetland (see Figure 12). Sediment samples were collected from thfee depths at each
station (0 to 2 inches, 2 to 15 inches, and 15 to 36 inches). Nine chemicals were
identified as COCs in wetland sediments; summary data for these chemicals are
presented in Table 5. ..
Table 5
Summary Data for Chemicals of Concern in Wetland Sediment
(Areas 48 and 49) (mg/kg)
- :Ii:::!::ii!,';j:::j::I:::::I::Iit'!'}::i:::::::!!j;:=:t::!:i:I:!:::::i:I!::::::I::i::lt:ltm::~~:ItY~m9.~::iI!1.:!::::!:i:::::::::!::t::I:!::::::::}!:'!ii:!:I:i:~:::!:::::~:i!:!::::I:i:::::::::i:.::ii:::!:t::':::I:!':::::!:!::;'::
!lli:::!i':::lljil'III'lf::lil!I'-Jltl: :lllli,:III18I:lfl:lllllillllll l'lljlll..ll:illlli: :llllljll~I.III:I!llil::f'i
Arsenic 1.40 6.75 2.56 7/8
Cadmium 0.77 0.77 0.77 1/8
Chromium 9.00 36.40 18.71 8/8
Copper 2.3 38.90 11.01 8/8
Lead 1.10 91.20 17.88 8/8
Nickel 11.00 55.6 23.80 6/8
4,4'-000 0.006 0.065 0.035 2/2
4,4' -DOE 0.004 0.79 0.216 4/4
4,4' -DOT 0.013 0.013 0.013 1/2
.Means were calculated by using detected concentrations only.
bFrequency of detection defmed as number of samples with detected concentrations of a chemical/total number
of acceptable samples. .
Note: Data represent samples from two depths (0 to 2 inches and 2 to 15 inches) from four stations along the
southern boundary of the freshwater wetland.
Inorganic substances showed relatively wide distribution (a frequency of detection of
6/8 to 8/8 samples), except for cadmium, which was detected once. Mean
concentrations of inorganic chemicals ranged from 0.77 mg/kg (cadmium) to
23.80 mg/kg (nickel). 4,4'-000, 4,4'-00E, and 4,4'-ODT were detected at mean
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concentrations ranging from 0..0.13 mg/kg (4,4'-DDT) to 0..216 mg/kg (4,4'-DDE). Too
few d~ta were available to enable conclusions on the spatial extent of these pesticides.
A single surface water sample was collected from the wetland north of Areas 48 and 49.
COCS identified in this sample included aluminum (16,70.0. p.g/L), chromium (92.6 p.g/L),
copper (158 p.gjL), iron (91,50.0. p.gjL), lead (146 p.gjL), mercury (0..38 p.gjL), zinc (260.
p.gjL), 4,4' -DDD (0..1 p.gjL), 4,4' -DD,E (0..1 p.gjL), 4,4' -DDT (0..1 p.g/L), and
benzo(a)anthracene' (5.5 p.gjL).
7.0 SUMMARY OF SITE RISKS
, '
The baseline risk assessment provides the basis for taking action and indicates the
, exposure pathways that need to be addressed by the remedial action. The identification
of the chemicals of concern, exposure assessment tOxicity assessment, and risk
characterization comprises the baseline risk assessment.' This assessment serves as the
baseline assessment indicating what risks could exist if no action was taken at the au 4.
This section of the ROD reports the results of the baseline risk assessment conducted for
this site.
Both human health and ecological baseline risk assessments (RAs) were performed for
au 4 to determine the potential risks associated with chemicals identified at the site.
The human health assessments were conducted in accordance with EP A's Risk
Assessment Guidance for Superfund, Volume I: lfuman Health Evaluation MQ!lUal (Part
A), EPA Region 10 SupplementOl Risk Assessment Guidance, and the Human Health
Evaluation Manual, Supplemental Guidance: Standard Default Exposure Factors. Tbe
ecological risk assessment followed federal guidance. The RA methods and results are
summarized in'the following paragraphs.
7.1
HUMAN HEALTII RISKS
The human health risk assessment evaluated potential risks associated with exposure to
chemical contaminants from au 4. All chemicals that were detected at least once were
carried through the risk assessment. The assessment considered potential exposure to
chemicals in groundwater, soil, sediment, and mussel tissues. Air (i.e., volatile chemicals
released from soil) and surface water were not eval~ated. Emissions of volatile
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chemicals from soil in~.; outdoor air was not evaluated because the results of the soil
vapor survey indicateu there was no source of volatile chemicals in soil. Inhalation of
volatile chemicals released into indoor air while showering, and inhalation of particulates
in outdoor air, was evaluated. Surface water was not evaluated because only one of the
four planned sampling locations contained surface water. It was detennined that one
sample station would not be an adequate representation of surface water conditions at
OU4.' .
7.1.1
Exposure Assessment
The purpose of the exposure assessment is to quantify contact with chemicals of potential
concern identified at the site. This is accomplished by identifying the exposure media,
potentially exposed populations (based on. current and future land use), the routes of
exposure, and quantification of human intake of chemical. Table 6 presents the
populations, media, and routes of exposure that were evaluated for each area.
.
Exposed Populations
Both current and future land uses have been considered in iqentifying potentially
exposed populations for each area. Three populations-current recreational, current
worker, and future residential-were considered. Populations evaluated for each area
were as follows:
.
Area 39:
Current recreational visitor
Future resident
.
Area 41:
Current occupational worker
Future resident .
.
Area 44:
Current occupational worker
Future resident
.
Areas 48 and 49: Current recreational visitor
Future resident
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Table 6
Populations, Media, and Routes of Exposure Evaluated at Areas 39,41,44,48, and 49
---
Soil YES YES YES - - - YES YES YES,
Groundwater - - - - - - YES YES YES
Sediment - - - - - - - - -
Mussels - - - - - - - - -
:ii#¥!t@}}::w~n:::::::}r:::::Jtfit:::t:::fr:::::::ttt~:ttt:::::@{:,t',::::@t::trt:::Jtt:j::=::::::::::::tttWHWt~IIItti:t/'i@JJ}jr:tI::Ift~tt::gIIlt::::t:iltI:@:l::ft::j:}t:ltft:I:W:}::fi!
Soil - - - YES YES YES YES YES YES
Groundwater - - - - - - YES YES YES
Sediment - - - NO NO NO YES NO YES
Mussels - - - - - - YES - -
Soil - - - YES YES YES YES YES YES
Groundwater - - - - - - YES YES YES
Sediment - - - NO NO NO YES YES YES
Mussels - - - - - - YES - -
i~W~:~J@!:!I:f::If~::j']ft:':':~!::::::::::::::i.:tI~:lM::I:::::::::::r:::::I;t:::~:~::w::::;:~::::~::::rl@f@:t:t::::,:::~:~:::~:t:'l::::I::::tI::::I~:::::I~::::::r::':MH;;m!MM:MrM:t::::H:::W::i.::::n:::::::::::~:::::~::@rtt:::::::::::t:t:::
Soil YES YES YES - - - YES YES YES
Groundwater - - - - - - YES YES YES
Sediment NO NO NO - - - YES ~O YES
Mussels NO NO NO, - - I - YES - I -
Notes:
NO = Pathway not evaluated ,
YES = Pathway evaluated
- = Pathway is not applicable for this receptor.
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.
Exposure Media and Pathways
The following media were evaluated:
.
.
Area 39:
Area 41:
Area 44:
Soil and groundwater
Soil, marine sediments, mussel tissue, groundwater
Soil, marine sediments, mussel tissue, groundwater, .
sump sediments (treated as soils)
Soil, marine sediments, mussel
tissue, groundwater
.
.'
Areas 48 and 49:
Although groundwater was evaluated, groundwater exposures are highly unlikely because
of hydrogeological limitations that would affect any drinking water supply wells. Because
OU 4 is adjacent to marine tidal waters, the aquifer has high salinity.
For these media, the following pathways were evaluated:
.
Soil:
Ingestion, dermal contact, and inhalation of suspended
particulates '
Ingestion, inhalation of volatiles, dermal contact while
bathing
Ingestion and dermal contact
Ingestion .
.
Groundwater:
.
.
Marine Sediments:
Mussel Tissue:
.
Exposure Point .Concentrations
The exposure point concentration (EPC) is calculated at the point the receptor (Le.,
potentially exposed human) can come into contact with a chemical (Table 7). Average
and reasonable, maximum exposure point concentrations were estimated for all media.
The soil values listed in Table 7 combine both surface and subsurface soils.
TabJe 7 presents exposure point concentrations and summary statistics for chemicals that
have been found to present a potential risk of concern (i.e., cancer risk greater than 10-4,
a noncancer risk greater than 1, and, for lead, blood level concentrations greater than 10
JLg Pb/dL for more than 5 percent of the population). The list of chemicals presented in
this table. is different from those identified as COCS in Section 6.2, Nature and Extent of
Contaminants, which also included chemicals that exceeded state risk criteria. Table 7
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Table 7
Exposure Point Concentrations for Chemicals of Potential Human Health Risk
for All M~ia in Areas 39,41,44,48, and 49
:ijlli:lltllll~.IIII:II.1111I JJlt{nf@fl1@ml1JJllHJ~@Jtt:W@1~ti~~ij!nmEnIm:mt~llt;l;@@:~:J:::~~:~:~:t:@fHl:g@mflf:~~~~l
*~~li~~~oo~~~tMmJJ~~~~~~~~~~l~~ :m:mIi~:?!itlgt;::~::M i~;mUJm.fq:t.~lm jj~~~j~~~~~~~~~~~~~f~JIg~~~~~~~~~1~~~ti~~~~
l~:;?:g::::::::::@t;:tt:]!:iilitt::::::t:tU:i:iI:;:I:::MdI;r~:::::::;:EI:::::f::;:::::t@i:Ii~l::::lHIlfHItm~:::m:~::fi;::::I::tlt:::::::::::tff:::f:::::::::I:::::]:fi:@ffI::i::::IMl;:::::::::;::r:;:;;::iB::ti:;::m:
Soil
Arsenic 6.6 6.6 8.5 6.6
Chromium 103 231 523 231
Lead 122 170 736 170
Groundwater
Manganese 0.47 0.88 0.89 0.88
;:;~M!:m::::;::mmH::t:::::::::::I::::@::::::::::::;:::::t::::::::::::::::i.tmI~@::::::::::::::::::::m:::::::Im:::::::I:::H@:::::::~::::::::~:::::i.~ttt:::m~::::::::::::{t:tI;:::::::i:::::::::::W:~::::::n::::::::::::::~:::::::::i.::i.:Im~:i.:;:r~ti.::i.:;:::::::::::::::m:r:::::::;:::I:t;:i::::mr::::::::iIt;::I
Soil
Lead 41 .8 65 298 65
Groundwater
Benzo(k)fluoranthene 0.005 0.01 0.007 0.007
I,3-Dichloropropene 0.007 0.03 0.014 0.014
Manganese 2.1 4.4 2.6 2.6
Vinyl chloride 0.002 0.01 0.004 0.004
:f~~%ml:mltIJ::~~:~::I:::::~:::::~;::ri:;i.r:~:I::t;:i.II:mIll!it~~~::t:t@::~~::~~:~:~MIt~mmmmr~tr::::m::t:::~~~1f~:::::r:~~I::::~::::t~~~~:~:@::::~Mm:!:i.;:~:::t:::IIll;::~ImftI;;!m:::N:::i.:I:::;Im~
Soil
Lead I 395 I 834 3,150 I 834
Sedimeot
Arsenic 29 50 48 48
Lead 2;1.97 3,976 3,625 3,625
Groundwater
Manganese 0.18 0.29 0.27 0.27
Groundwater
Benzo( a)anthracene 0.002 0.003 0.006 0.003
Benzo(k)fluoranthcnc 0.002 0.003 0.005 0.003
Indeno(~cd)pyrene 0.006 0.01 0.033 0.01
Notes:
95% UCL = 95% upper confidence limit of the arithmetic mean of the untransformed data set.
RME = Reasonable Maximum Exposure .
ppm = part per million
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includes all the chemicals identified as posing a potential risk of concern in the human
health risk assessment, as well as those chemicals that, when added together, posed a
risk greater than 10-4 or 1. ' ,
.
Chemical Intake by Exposure Pathway
Chemical intakes for each exposure pathway were calculated by combining.the EPCs
with other exposure parameters'such as water ingestion rates, inhalation r~tes, soil
ingestion rates, dermal absorption rates, body weights, and exposure frequencies and
durations in accordance with EP A guidance.
7.1.2 Toxicity Assessment
The purposes of the toxicity assessment are (1) to weigh the available evidence regarding
the potential for chemicals to have adverse effects on exposed individuals (Le., hazard
identification) and (2) to provide a quantitative estimate of the relationship between the
magnit\lde of exposure and'the likelihood or severity of adverse effects (Le., dos~ .'
response assessment). Toxicity values are derived from epidemiological or animal
studies to which uncertainty factors are applied (to account for the use of animal data to
'predict effects on humans). The primary sources for toxicity values are EPA's Integrated
Risk lnfonnation System (IRIS) database and the Health Effects Assessment Summary
Tables (HEAST). Table 8 lists the toxicity values identified for the chemicals presenting
risks of concern. .
Slope factors (SFs) have been developed by EPA for estimating e~cess lifetime cancer
'risks associated with exposure to potential carcinogens. SFs are expressed in units of
. (mg/kg-dayt1 and are multiplied'by the estimated daily intake rate of a potential
carcinogen, in mgjkg-day, to provide an upper-bound estimate of the excess lifetime
cancer risk associated with exposure at that intake level. The term "upper bound"
reflects the conservative estimate of the risks calculated from the SF. Use of this
approach makes underestimation of the actual cancer risk highly unlikely. Slope factors
are derived from the results of human epidemiological studies or chronic animal
bioassays to which animal-to-human extrapolation and uncertainty factors have been
applied (e.g., to account for the use of animal data to predict effects on humans).
Reference doses (RIDs) have been developed by EP A for evaluating the potential for
adverse health effects associated with exposure to noncarcinogenic chemicals. RIDs are
expressed in units of mg/kg-day, and are estimates of acceptable lifetime daily exposure
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Table 8
Toxicity Values for Chemicals of Concern
Carcinogenic EtTects
1111I111~llf~llt!II'[r~llltJII!ljlt. :&ili:;t:~mmi@j:~i:1:ii:i:i:jm~1iiii!\ti!i:i:*1j.~I!g\it.~!~!)!ii!;1!!!i~iiit~~ti~\~ifuiill1[::ijij:i1ii!!:::j:iji::lii
iwf¥¥iflWif@!ij:1\!! ~1~1~I~~~~~~-~~~~~~1~~~%1~ ~i:{~'~_M~*f:~ ~~~*~~~1~~Jlmilif~~~~~~~~~
Arsenic 1.75 IRIS 51 HEAST
Benzo(a)anthracene 7.3E-1 A 6.1E-l A
Benzo(k)fluoranthene 7.3E-1 A 6.1E-l A
Chromium VI - - 4.1E + 1 HEAST
1,3- Dichloropropene 1.8E-l IRIS 13E-l IRIS
Indeno( 1,2,3-cd)pyrene 7.3E-1 A 6.1E-l A
Vinyl chloride 1.9 HEAST 3.0E-l HEAST
NOQcarcioogeoic Effects
--~~-
Arsenic 3E-4 IRIS. 3 Skin, keratosis,
hyperpigmentation
Chromium SE-3 IRIS 500 None
1,3- Dichloropropene 3E-4 IRIS 5.71E-3 IRIS 10,000 30 oral-increased weight
inh-nasal mucosa
Manganese (water) SE-3 IRIS 1. oral-CNS effects
inh-respiratory
psychomotor
Notes:
A = The cancer slope factor for this compound has been estimated by multiplying the cancer slope factor for
benzo(a)pyrene by a toxic equivalency factor taken from the new Region IV Guidance Document, U.S. EPA,
1992.
IRIS = Integrated Risk Information System (U.S. EPA database)
HEAST = Health Effects Assessment Summary Tables (U.S. EPA)
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levels for humans, including sensitive individuals. Estimated intakes of chemicals of
concern from environmental media (the amount of a chemical ingested from
contaminated drinking water) are compared with the RID. RIDs are derived from
human epidemiological studies or animal studies to which uncertainty factors have been
applied (e.g., to account for the use of animal data to predict effects on humans).
Toxicity values are only available for the oral and inhalation pathways. EP A has not
published toxicity values for evaluating the dermal pathway. The agency recommends
using the oral toxicity values to evaluate dermal exposure.
Because of its unique toxicity, lead does not have a verified reference dose. Instead,
EPA recommends an alternative approach to evaluating lead toxicity. This approach
involves using EP A's LEAD 0.5 model to estimate blood lead levels resulting from
multi pathway exposures. The results of this model are used to determine whether the
lead present in different media at the site pose a potential risk to children. .
7.1.3 Risk Characterization'
The risk characterization integrates the information developed in the toxicity assessment
and exposure assessment to develop carcinogenic and noncarcinogenic risks. The
National Contingency Plan has determined a target for cleanup levels in the range of 1O~
to 10-4 risks. Any risks greater than 10-4 requires remedial action. In this section,
chemicals (or a combination of chemicals in the same media) with a cancer risk greater
than EP A's acceptable risk range will be discussed.
A noncarcinogenic risk greater than 1 suggests that exposure to a site chemical exceeds
the reference dose and therefore may present a potential health threat.
For inorganic compounds. that have been identified as chemicals of concern, a
comparison with background concentrations was conducted to determine the contribution
that naturally occurring levels may make to site risks. (Th~ complete range of chemicals
in different media at the site are presented in the Final RI and is part of the
Administrative Record).
Tables 9 through 12 present noncancer and cancer risk summaries for each area at
au 4. Risks that exceed the EP A acceptable levels were found only for the future
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resident scenario. Risks are presented for groundwater; however, as discussed
previously, the groundwater is not suitable for drinking because of naturally occurring
salini ty .
The CERClA-based human health risk assessment showed concentrations of arsenic in
mussel tissue at the. upper limit of acceptability of the EPA Target Risk Range.
However, the concentrations of arsenic found in mussel tissue were identical to those
taken from background reference stations in both Oak and Crescent Harbors. Further,
an EP A stUdy of shellfish in Puget Sound concluded that 99 percent of the total
concentration of arsenic found in shellfish is organic, which is the nontoxic form of
arsenic. The remaining concentration of inorganic arsenic found in mussel tissue would
show a risk below the EP A Target Risk Range.. Organic chemicals (primarily P AHs) in
mussel tissue were elevated relative to background mussel tissue collected from adjacent
reference stations but show a carcinogenic risk only at the 10-6 range and no ecological
risk.
The. following. summarizes the risks found at the five areaS.
.
Area 39
Soil. Lead was found to pose a potential risk when the reasonable maximum exposure
point concentration was used in EP A's LEAD 0.5 model. Chromium and arsenic
together were found. to produce the noncancer risk.
Groundwater. . Arsenic and manganese were found to produce a non~cer risk.
However, arsenic risks were primarily attributed to .naturally occurring concentrations of .
arsenic.
.
Area 41
Soil. No CERCLA risks were found.
Groundwater. Manganese was found to produce a noncancer risk. Vinyl chloride,
benzo(k)fluoranthene, and 1,3-dichloropropene were found to produce cancer risks.
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Table 9
Area 39-Summary of Cancer and Noncancer Risks
- :iM!i::i:ii!;~:~t:~!;%ll;~~@g_~J~a'lY-ltH~Hj;iI:~~;~~~!t~:~I:tt:!~i:ii: ::iUlt!I~:im~t!~pj~::ii~:t:n
:lli\t1i_!E*IJifl; 11~~_lli~}i~ I~~~1~f:~i~1~ili!!Ei!i~~*i~t~f:f~~~~j
~~.i- 1~~m.411 tN&\1BiIi ~~1_i~~ :il~.i ~!@rglf!ili::;i
:-:.:..;.:.:.x.:.:.:-:.:.:.:.:.:.:.:.:.:.:-:.:.:.:.:-:.
Soil" Ingestion 2.4E-02 B S.IE-07 B - - 1.4E of D\) E 2.5E-OS .R
Inhalation 4.1E-05 B 6.0E-09 B - - 1.9E:Q3 B 4.8E-07 B
Dermal 3.1E-03 B I.5E-07 B - - 3.1E-02 B 7.4E-07 B
Combined 2.7E-02 B 6.7E-07 B - - 1.4E + 00 E 2.7E-OS R
Groundwater Ingestion - - - - 6.7E + 00 E 2.0E-OS R
Inhalation - - - - 1.6E-Q4 B I.3E:.07 B
Dermal - - - - 3.9E-02 B 6.6E-07 B
Combined - - - - 6.7E +00 E 2.1E-OS R
Sediment Ingestion - - - - - -
Dermal - - - - - -
Combined - - - - - -
All Media Total Combined 2.7E.{)2 B 6.7E-07 B - - 8.lE + 00 Eb 4.8E-05 Rb
"Evaluated using the child/adult integrated approach per U.S. EPA (1991) Region 10 Guidance.
bExciuding risk from groundwater. which is subject to saltwater intrusion, the total noncarcinogenic risk is 1.4,
the total carcinogenic risk is 2.7E-OS. .'
Notes:
B - Below or at limit of target noncancer Hazard.lndex (m s; 1), or cancer risk (~eds Lifetime Cancer Risk
EI,.CR s; 1 x 1~) ..'. . . . .
E - Exceeds EPA target.for noncancer Hazard Index (HI > 1), or cancer risk (ELCR > 1 x 10"")
R - Within EP A target cancer risk range (ELCR > 1 x 10~ and < 1 x 10"")
- - Not evaluated.
~.
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Table 10
Area 41-Summary of Cancer and Noncaneer Risks
- tt'lW{~t~]~~i~1*~ffi~~~~fl~~~tllii!~_1IiiI$1**Iilli~IiWl~f$ ~~li_!!~glfViiit~~~t~
:~Ii~~1~~fl~~liii!~!~~~~1~r~~~jir ~~ii~iblM!_iil~~j~~~~~iift ~~~1~~t~g!!!!!!111IIi1~~~~
ltli!!.1, :;it:;I9i!!iiM!: :t&I!!I.~:~ :1::::~m:iI!Bi:;[::\l :[~~I :t{\Ij!,t!:!:tlli
Mussel Ingestion - - - - 3.0E-1 B 53E-05 Ra'
SoiF Ingestion - - 2.6E-02 B 1.7E-06 R 1.0E+00 E 2.5E-05 R
Inhalation - - 1.6E-04 B 52E-06 B 42E-06 B 3.8E-10 B
Dermal - - 5.8E-03 B 4.1E-07 B 2.2E-02 B 7.4E-07 B
Combined - - 3.2E-02 B 7.3E-06 R 1.0E+00 E 2.6E-05 R
Ground- Ingestion - - - - 1.6E+01 E 1.9E-04 E
water
Inhalation - - - - 3.2E-03 B 1.6E-06 R
Dermal - - - - 93E-02 B UE-06 R
Combined - - - - 1.6E+01 E 2.0E-04 E
Sediment Ingestion - - - - 9.0E-04 B l2E-07 B
Dermal - - - - 1.8E-04 B 2.4E-08 B
Combined - - - - 1.1E-03 B l.5E-07 B
All' Media Combined - - 3.2E-02 B 7.3E-06 R 1.7E+Ol EC 2.8E-04 EC
Total
Notes:, . ,
~Risk is due 'to background arsenic levels. This risk is based on the assumption that 100 percent 'of the arsemc
that waS detected in tissue is present in its. inorganic form. . However, research indicates that 99 percent of
arsenic in seafood occurs primarily as a complex methylated' or organic species and that the organic form of
arsenic is less toxic and more readily excreted than inorganic arsenic. Therefore, when adjusting this risk to
represent the more toxic, inorganic form of arsenic, the risk is 53E-07.
"Evaluated by using the child/adult integrated approach, per U.S. EPA 1991) Region 10 guidance.
"Excluding risk from groundwater, wbich is subject to saltwater intrusion, the total noncarcinogenic risk is 13,
the total carcinogenic risk is 2. 7E-05.
B =. Below or at limit of target noncancer Hazard Index (HI ~ 1), or cancer risk (Exceeds Lifetime Cancer Risk
ELCR ~ 1 x 10~)
E = Exceeds EPA target for noocancer Hazard Index (HI > 1), or cancer risk (ELCR >1 x 10"")
R = Within EPA target cancer ,risk range (ELCR > 1 x 10-6 and < 1 x 10"")
- = Not evaluated or applicable
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Table 11
Area 44-Summary of Cancer and Noncancer Risks
-=== ~~TIlli@I..;::~D.i9IJ.1~@:I:~::::
@Ji@l~j~:i.}.lillffi1MitiK
:;91«4- :a1_~I~~
Mussel Ingestion. - - - - 3.1E-Ol B 5.6E-05 R&
Soil Ingestion - - 2.5E-02 B 3.0E-06 R 13E+00 E 4.5E-05 R
Inhalation - - 1.2E-04 B 2.6E-08 B 4.5E-04 B 7 ~8E-08 B
Dermal - - 2.5E-03 B 2.9E-07 B 2.8E-02 B 13E-06 R
Combined - ~ ;:E-02 B 3_: E-06 R 13E+00 E 4.6E-05 R
- -.
Ground- Ingestion - - - - 1.1£ +00 E 13E-05 R
water Inhalation - - - - 1.0E-04 B 13E-07 B
Dermal - - - - 1.0E-02 B 6.0E-07 B
Combined - - - - 1.7E+00 E 1.4E-05 R
Sediment Ingestion - - - - 9.8E-07 B 1.4E-I0 B
Dermal - - - - 20E-04 B 28E-06 B
Combined - - - - 20E-04 B 28E-06 B
All Media Combined - - 2.8E-02 B 33E-06 R 33E-OO EC: 1.1E-4C:
Total
Sump Ingestion - - 1.4E-Ol B I.5E-05 R 4.0E+00 E 1.4E-04 E
Sediment Inhalation 4.IE-04 B 1.1E-07 B 21£-02 B 1.2E-07 B
(as SOil)b - -
Dermal - - 1.5E-02 B 1.5E-06 R 9.0E-02 B 4.4E-06 oR
Combined - - 1.5-01 B I 1.6E-05 R 4.IE+00 E I.5E-04 E
aRisk is due to background arsenic levels. This risk is based on the assumption that 100 percent of the arsenic
that was detected in tissue is present in its inorganic form. However, research indicates that 99 percent of
arsenic in seafood occurs primarily as a complex methylated or organic species and that the organic form of
arsenic is less toxic and more readily excreted than inorganic arsenic. Therefore, when adjusting this risk to
represent the more toxic, inorganic form of arsenic, the risk is 5.6E-07. .
"Sump sediments have been evaluated as soils in an independent, highl\' hypothetical assessment.
"Excluding risk from groundwater, whic:;h is subject to saltwater intrusil. . the total noncarcinogenic risk is 1.6,
the total carcinogenic risk is 4.9E-05. . .
Notes:
B = Below or at limit of target noncancer Hazard Index (ID :::;; 1), or C<.I.. . ~r risk (Exceeds Lifetime Cancer R :5k
ELCR :::;; 1 x 1~)
E = Exceeds EP A target for noncancer Hazard Index (ID > 1), or cancer risk (ELCR > 1 x 1~)
R = Within EP A target cancer risk range (ELCR > 1 x 10-<> and <. 1 :. 10"4)
.' - = Not evaluated or applicable
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Table 12
Areas 48 and 49-Summary of Cancer and Noncancer Risks
. . :~;:ji:::::i~:::::~:Ii:i:::::::i::f:H:t:I::~::::1@!!m::~J@~ifl~::::1:::::::::t::::::1Hl:Ii::::::::::::::Ii:::1;:;: ::::i::;::::::::::I~m~r£aii~:::Y~~:~:::::::I::::::::
:t.tII:Il~_:;:I@:m:i: ~~~~~~~~~~1$~~PBtmgi1~~ij~~~~~~~~~ ~I:~:Mt:::::::::::::~!&!iHm1:::::ilil::lli
IN*!I!~M :::::::::i::.!!9:i::~1: :iiil(,,$.;m*:!. ::~::::mmlH:!:::::::::::: :i::I9.i.~f ::i:::::::::g#".i:::::::::
Mussel Ingestion - - - - 4.0E-Ol B 7.5E-05 Ra
Soil Ingestion 1.5E-02 B 4.3E-07 B - - 4.4E-Ol B 12E-05 R
Inhalation 2.5E-05 B 2.5E-09 B - - 1.8E-06 B 1.8E-I0E
Dermal 1.4E-03 B 5.6E-08 B - - 1.0E-02 B 1 .0E-06 R
Combined 1. 7E-02 B 4.9E-07 B - - 4.5E-Ol B 1 .3E-05 R
Ground- Ingestion - - - - 1.2E + 00 E 2.2E-04E
water Inhalation - - - - 2.8E-03 B 5.4E-06 R
Dermal - - - - 8.0E-02 B 6.4E-07B
Combined - - - - 13E+OO E 23E-04 E
Sediment Ingestion - - - - 5.6E-04 B 8.1£-06 B
Dermal - - - - 1.5E-05 B 1.8E-06 B
Combined - - - - 5.8E-04 B 1.0E-07 B
All Media Combined 1.7E-02 B 4.9E-07 B - - 2.15E + 00' 3.1E-04 ~
Total
aRisk is principally due to background levels of arsenic. This risk is based on the assumption that 100 percent
of the arsenic that was detected in ~ue is present in its inorganic form. However, research indicates that 99
percent of arsenic in seafood occurs primarily as a complex methylated or organic species and tJ:aat the organic
form of arsenic is less toxic and more readily excreted than. inorganic. arsenic. Therefore, when adjusting this
risk to represent the more toxic, inorganic form of arsenic, the risk is 6.1E-06. .
bExcluding risk from groundwater, which is subject to saltwater intrusion, the total noncarcinogenic risk is 0.85,
the total carcinog~nic risk is 1.9E-05.
Notes:
B = Below or at limit of target noncancer Hazard Index (HI S I), or cancer risk (Exceeds Lifetime Cancer.
Risks ELCR SIx 10-6)
E ~ Exceeds EPA target for noncancer Hazard Index (HI > 1), or cancer risk (ELCR > 1 x 10-1)
R = Within EP A target cancer risk range (ELCR > 1 x 1
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.
Area 44
Soil and Sediment (Sumps). Arsenic was found to produce noncancer and cancer risks.
In addition, lead was found to produce a human health risk. '
Groundwater. Manganese was found to produce a non cancer risk. However, manganese
risks were primarily attributed to naturally occurring concentrations of manganese.
.
Areas. 48 and 49
Soil. No CERCLA risks were found.
Groundwater. Manganese and arsenic were found to produce noncancer risks.
However, risks from on-site manganese concentrations are similar to risks associated
with background concentrations of manganese.
7.1A Uncertainty
Some degree of uncertainty is associated with each step of the risk assessment. Sources
of uncertainty are discussed below. ' .'
.
Toxicity Assessment
There are many toxicity assessment uncertainti~s associated with the database (e.g.,
differences in study design, species, sex, route) that is used to develop the toxicity value,.
, The magnitude and direction of uncertainty, associated with the toxicity values are
uIiknown. .
As discussed in the toxicity assessment, oral toxicity values have been used for evaluating
dermal exposures. The magnitude and direction of uncertainty associated with this
approach are unknown.
Although the speciation of chromium was not identified, the toxicity values used to
evaluate chromium are based on the carcinogenic form of chromium (chromium VI).
Using this value will probably'result in an overestimate of risk, since it is unlikely that all
the chromium detected on site is in its carcinogenic form.
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The toxicity value for arsenic is overly conservative. The Puget Sound Estuarine
Program study showed that 99 percent of the arsenic found in Puget Sound shellfish is in
a nontoxic form. The arsenic analysis was for total arsenic, and it did not distinguish
between the toxic and nontoxic forms. A new evaluation, assuming that one percent of
the arsenic found in mussels is, toxic, shows that mussel consumption up to 10 times the
ingestion rate evaluated in the RI is acceptable.
.
Exposure Assessment
The exposure assumptions used in the risk assessment are default values recommended
by EP A. These values are not site-specific. and are intended to be overly conservative.
They are used to insure that site risks are not underestimated.
Since the groundwater is not potable, ingestion of groundwater is not likely. Thus, while
the groundwater was evaluated to calculate a worst-case scenario, the result is an
overestimation ()f total site risk.
.
Risk Characterization
Some uncertainty is associated with the summation of risks for multiple chemicals. For
example, not all noncarcinogenic chemicals have toxic effects on the same organ.
Therefore, combining individual chemical noncancer risks may yield a conservative
estimate. .
. 7:2 . ECOLOGICAL RISKS
A screening-level ecological risk assessment was conducted to evaluate potential
toxicological threats to ecological receptors associated with contamination from au 4.
7:2.1 Exposure Assessment
.
Terrestrial »ab~tat
Areas 39, 41, and 44 are largely urbanized or industrialized and do not contain sufficient
habitat to sustain ecologically functional plant or animal communities. Therefore, an
ecological risk assessment of terrestrial habitats in Areas 39, 41, and 44 was not
performed. The terrestrial portion of Areas 4S and 49 is dominated by a grass and
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SEAPlANE BASE, OPERABLE UNIT 4
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Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0042 .
Record of Decision
Date: 12/15/93
Page 50
brushland plant community utilized by small mammals, carnivorous mammals, and
rap tors. Animals primarily become exposed to chemicals present in soil by incidental
ingestion of soil, consumption of plants that accumulate chemicals from soil, and
ingestion of prey that accumulate chemicals from ingestion of soil and plants.
.
Marine Habitat
The near-shore marine habitat adjacent to Areas 41, 44, 48, and 49 was also sampled to
determine whether contamination had migrated to the marine sediments. The substrate.
of Crescent and Oak Harbors is principally mud and silt with some fine san~, coarse
sand and cobble, and rocks. Organisms using the intertidal zone include algae, some
benthic invertebrates (crustaceans and mussels), fish, shorebirds, waterfowl, and
mammals. The substrate is not conducive to clams and only a very limited number were
observed during field sampling. Organisms are exposed to sediment-borne chemicals.
. through ingestion of sediment, direct uptake of chemicals from sediment and overlying
water, ingestion of water, and ingestion of plants and prey that accumulate chemicals
from sediment and water. . . .
.
Wetland Habitat
The wetland north of Areas 48 and 49 was sampled to determine whether contamination
at Areas 48 and 49 had migrated off site. The wetland is freshwater, with a
semipermanent, seasonal water regime. Organisms inhabiting the wetlands include
hydrophytic plants, plankton, invertebrates (insects, worms, crustaceans), waterfowl,
shorebirds, amphibi~, raptors, and mammals (otter, muskrat, mink, raccoon). Animals
are exposed to chemicals in water and sediment through, ingestion of water and .
sediment, ingestion of pl.ants that accumulate chemicals from soil and water, and
ingestion of prey that accumulate chemicals.
7.2.2 Toxicity Assessment
The screening-level risk assessment of potential ecologiqU risks compared concentrations
of chemicals in sediment with sediment quality values, and surface water with ambient
water quality criteria. Potential exposures of terrestrial receptors to chemicals detected
in the soils were compared with toxicity reference values. Toxicity reference values were
selected to be protective of target organisms following chronic and continuous exposure
to chemicals. .
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SEAPLANE BASE, OPERABLE UNIT 4
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Engineering Field Activity, Northwest
Contrat;t No. N62474-89-D-9295
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Date: U/15/93
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Toxicity reference values for mammals and birds were expressed as a dose and were
obtained from a review of available mammalian and avian toxicological data. Toxicity
values for marine sediments were either the Sediment Quality Standards (Washington
State Sediment Management Standards), values obtained from other sediment
toxicological data, or values derived from equilibrium partitioning for non-ionic organic
chemicals. Freshwater sediment toxicity reference values were either obtained from
,toxicological information compiled by the Washington State Department of Ecology or
derived from equilibrium panitioning for non-ionic organic chemicals. Freshwater
toxicity values were either federal ambient water quality criteria or obtained from a
review of available aquatic toxicity data.
7.2.3
Risk Characterization
.
Terrestrial Habitat, Areas 48 and 49
Potential ecological risks from chemicals detected in soil in Areas 48 and 49 were
evaluated by using an exposure modeling approach. Modeled receptors included the
vole (a small herbivorous mammal), coyote (a carnivorous mammal), and northern
harrier (a carnivorous bird). Results of exposure modeling suggest that potential risks
'were negligible for all chemical~ and receptors, with the exception of copper and lead for
the vole. However, comparison of site chemical concentrations with background
concentrations and available tOxicity infonnation indicated that potential risks to vole are '
primarily d~e to background concentrations of copper and lead.
.
Marine Habitat Adjacent to Areas 41, 44, 48, and 49
, Potential ecological risks from chemicals detected in marine sediments were evaluated by
comparing sediment chemical concentrations with sediment toxicity reference values and
by conducting a laboratory toxicity test (e.g., MICROTOxn' chronic bacterial toxicity
test). Results of toxicity tests on surficial sediment from each station showed no effect,
except for station 48j49-MS-IO, which confirmed a low potential for ecological impacts.
Exceedance of sediment toxicity reference values was more common in subsurface
sediment samples, but evidence suggests that chemical deposition was a historic process
and that natural capping with clean sediment is occurring. It is concluded that the
potential for adverse impacts on aquatic organisms from chemicals detected in sediments
in the intenidal zone adjacent to Areas 41, 44, 48, and 49 is low.
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SEAPLANE BASE, OPERABLE UNIT 4
U.s. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0042
Record of Decision
Date: U/15/93
Page 52
Potential ecological risk from consumption of mussels that accumulate chemicals from
the marine habitat was assessed by using an exposure model with a raccoon as the
receptor. Negligible potential risk was posed to the raccoon from consumption of
mussels from Areas 41, 44, 48, and 49.
.
Wetland Habitat North of Areas 48 and 49
Potential ecological risks posed by chemicals in freshwater sediments were eV
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SEAPLANE BASE, OPERABLE UNIT 4
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Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0042
.
Record of Decision
Date: 12/15/93
Page 53
chemicals are uniformly distributed across a site. However, chemicals may
be limited to a small portion of a site. Exposure and potential risk may
therefore be overestimated.
.
Risks to aquatic organisms from chemicals detected in surface water in the
wetland north of Areas 48 arid 49 is highly uncertain because the
evaluation was based upon analytical results from a single water sample.
Spatial and temporal variability in concentrations of chemicals in surface
water can be great, but the magnitUde and direction of this uncertainty is
unknown.
Toxicity Assessment
.
Toxicity reference values were not available for all chemicals. . Potential.
risks may therefore be underestimated.
.
Toxicity reference values were often not available for target. sp.ecies. .
Therefore, values for surrogate species were used. The magnitude and
direction of uncertainty associated with extrapolating toxicity values
between taxonomic groups is unknown.
.
Toxicity reference values were often selected from a limited database. The
magnitude and direction of uncertainty associated with these values is
unknown.
.'
. .
Toxidty reference values for surface water assumed that the' chemical is
present in its most biologically available and most toxic form. However,
the site-specific characteristics of chemicals are unknown, and chemicals
are seldom "found in the environment in their most toxic form. Therefore,
potential risks are probably overestimated.
8.0 REMEDIAL ACl10N OBJEcrIVES
ACtUal or threatened releases of hazardous substances from this site, if not addressed by
implementing the response action selected in this ROD, may present an imminent and
substantial endangerment to public health, welf3J'e, or the environment.
30420\9311.04O\tcxt
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SEAPlANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract'
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
era 0042
Record of Decision
Date: 12/15/93
Page 54
Sampling results and the risk assessment indicate some human health risk to hypothetical
future residents in shallow soils, groundwater, and marine sediments. Remedial action
will be conducted at those areas where there are unacceptable CERCLA human health
risks and/or where chemicals exceed state standards. Several chemicals exceed'
Washington State's Model Toxies Control Act (MTCA) criteria at Areas 39, 41, 44, and
48. CERCLA risks were found in Areas 39 and 44.
8.1
SOILS
Remedial action objectives for surface soils in Areas 39, 41, 44, and 48 are to minimize
contamination of surface water; to minimize direct contact of humans and animals with'
COCs; to reduce concentrations of contaminants in the surface soil and Area 44 stOrm
drain system sediments to comply with applicable state and federal regulations; and to
prevent further migration of these contaminants. Specific numeric goals for each area
are presented in Table 13.. '
Table 13
State of Washington Cleanup Criteria
-
39 Arsenic 20
Chromium 400
Lead 250
PAHs (carcinogenic) 1
4,4'-DDD 4. 17
4,4' -DDE 2.94
41 Lead 250
4,4' -DDE 2.94
4,4'-DDT 2.94
44 Arsenic 20
Lead 250
48 PAHs ( carcinogenic) 1
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SEAPLANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
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Record of Decision
Date: 12/15/93
Page 55
.
Area 39 Soils
Shallow soils in Area 39 require remedial action because the lead concentration in the
southern swale would produce excessive lead concentration in blood for a hypothetical
future resident. In addition, arsenic, chromium, P AHs, and pesticides were detected in
excess of Washington State cleanup levels. Most of the COCS are in the top 1 to 2 feet
of the soils. An isolated PAH exceedance was detected south of Building 49. Because
this location is capped beneath the existing asphalt, remediation is not necessary. .
.
Area 41 Soils
Two to five cubic yards of shallow soils in Area 41 require remedial action because
pesticides were detected near the foundation of Building 25 in excess of Washington
State cleanup levels (see Figure 10). The one exceedance of the MTCA lead cleanup
value detected did not pose a health risk. COCS exceeding MTCA cleanup levels are
within 1 to 2 feet of the surface.
.
Area 44 Soils and Sediments
Shallow soil and some storm drain sedimentS in Area 44 require remedial action because
arsenic and lead concentrations would constitute a human health risk to hypothetical
future residents, and exceed Washington State cleanup levels (see Figure 1.1).
.
Area 48 Soils
Shallow soilsiri Area 48 require remedial action because elevated levels of P AHs were
detected in shallow soils. The P AHs above MTCA levels were detected in the top 1 to 2
feet of the soil column.
.
Area 49 Soils
No remediation is planned for Area 49 because the site does not pose a CERCLA risk
and no chemicals were detected above MTCA levels. .
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SEAPLANE BASE, OPERABLE UNIT 4
U.$. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0042
Record of Decision
Date: U/15/93
Page 56
8.2
GROUNDWATER
Groundwater sampling showed low concentrations of arsenic, manganese, VOCs, and
SVOCs at Areas 39, 41, 48, and 49. However, groundwater is not a current or potential
future source of drinking water at OU 4 because of saltwater intrusion and the proximity
to Oak and Crescent Harbors: The COCS found in the groundwater are not migrating to
the marine environment in sufficient concentrations to contribute to any risks.
Therefore, there are no recommended action objectives for groundwater. .
8.3
MARINE SEDIMENTS
Marine sediments will not be remediated because'the marine environment would be
harmed more by the cleanup activities than if the chemicals were left in place. Risk
analysis has determined that there are human health risks resulting from harvesting and
consumption of shellfish found at O~ 4 but they are within EP A's target cancer risk
range (greater than 10-6 and less than 10-4). Some ecological risks were found in the
marine sedimentS, most of these at lower levels in the sediment column.S, indicating that
a natural capping process was occurring. Screening-level biological testing indicated .
moderate toxicity at only one marine sediment location in Areas 48 and 49.
8.4
WETLANDS
No remediation is planned for the wetland north of Areas 48 and 49. Some low risks.
. were. determined in the wetland; however, a pathway from Areas 48 and 49 could not be
fo~d. The wetland is an old saltwater marsh that is hydrologically up gradient of OU 4.
The COCS found may be attributable to other sources such as sewage treatment lagoons
and upstream agricultural areas. The pesticides detected may be from past basewide
spraying activities. Also, damage to the environment from any remediation is considered
greater than the potential benefits of such remediation. .
In an effort to establish that no pathway exists between Areas 48 and 49 and the
wetland, samples will be collected at five surface water locations and four existing
groundwater wells. The surface water samples will help clarify whether COCs are
transponed to the wetland by a stream entering from the nonh, by a main storm drain
discharge located at the southwest comer of the wetland, of by the wastewater lagoons.
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SEAPlANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract .
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0042
Record of Decision
Date: 12/15/93
Page 57
Previous sampling data indicate that Areas 48 and 49 are not a source of the metals and
pesticides detected in surface water collected from the wetland.
Groundwater samples will be collected from existing monitoring weUs (48j49-MWS-l,
48j49-MWS-4, 48j49-MWS-6 and 48j49-MWS-7). One surface water sample will be
collected at the existing station (48j49-SW-3). Four surface water samples (48j49-SW-4,
48j49-SW-5, 48j49-SW-6, and 48j49-SW-7) will be collected at new locations. See
Figure. 13 for surface water and groundwater sampling locations. .
All new sampling locations will be sUlveyed using a base coordinate system to allow
relocation of the sampling points if necessary. All water samples will be analyzed for
total and dissolved metals and for pesticides. The additional data will help identify
potential sources of metals and pesticides exceeding freshwater quality standards and will
supply information to confirm the absence of a pathway between Areas 48 and 49 and
the wetland.
. The current information. indiCates no need for remediation. Remedial activities are not..
envisioned as a result of this additional sampling. The potential for damage (0 the
wetland as a result of remediation is considered greater than the potelltial benefits of
remediation.
The analysis results will be submitted in a brief report to the appropriate federal and
state agencies.
. 9.0 DESCRIPTION OF ALTERNATIVES
The results of the remedial investigation revealed that four of the five areas in OU 4
have some surface soil concentrat~ons requiring remedial action. The principal ARAR
for these remedial actions is MTCA, which lists cleanup standards. Four alternatives
were evaluated as possible remedial actions. Alternative 3, soil cover, was only
appropriate for Area 39 and was not considered for the other areas.
9.1
ALTERNATIVE 1: NO AcrION-AREAS 39, 41, 44, AND 48
This alternative is ~cluded for comparison purposes under CERCLA. Alternative 1
would not require any action. It does not sufficiently protect human health and the
-------
~ '~ t W"'ew.'~ S"~I;""n L"oon ,I "J U
48/49.SW.5 '~ "...( "'~\ .ill. "'1 c:I ] (i" ,
.Uk ..ili. .-UG. . {- ; ..ili,. f>"..ili. '~~~t' . - :', ',;:,,:-=~~:;~"~~.:~':~'~::::=~:":::::::~3 IJ
.w. SEAPLANE BASE i i,;\ ~:\ If ' ' ;':;, > ,,-liJ..' ,- " -ili. -ili."':'"
48/49.SW.7 SALVAGE YARD ..ili.f'~{ ( ) (.ill. :\~\ ill ",/ \~~~ .""\/ -. . "'"
(AREA 48) ..-, \. ! . \, \ \ . '~, "'..ill. """"0 '< 5
..ili. ... 2".. . )' r' '\/ <.. "" '\, ~ J=,Ef\ \f-JA'i. ,../ ~
.ill. ..\k .ill. "~..../ />\i'<,,'" ..):ili.. " ..'\ ~,~\ E~Si PIoN' I: .
r'\.. ../ ", . =., ' II \ 48149.SW.3' ' ~
. '" '--", 48149.MWS.~- " 48/49.SW.4 " Il ,..... "./ ~ ' }~,\;.. ;;
,./ \. ..._J T ~, /+48/~~.MWS.4 "/":::;';~_:'>
.' ..... - - --- 48149.MWS.7 -+- .- ,..,-,' \~ /-<;'::::: ::::: :// ..,."
/' .~ ~'", \ . ''''''';0 ~;...o ,..,.....:--
/ . '- \\ , ".. :::::'" .- /-
~ . 'Of" ,. .,.. ~---......'
, 48149.MWS.1 -~'- ... ... ~/ ",,/
" ~ /'/' , ". ..,. ~ ~..'?:~_..-:'- .-~.-....
\ r-;; "5_,...' .\ ,.' , ~~~;::::.-;/-
\ ~ . ./ ....~_. ,"
A ,/ ""........ .,." ~~",......'" . ",.~...-: .," .
\ , '-:: ~ .." .
I ;' ~ ~ .. ,.: ..' :.:. .
';JI; "'" ,,10 " ..."'~~'.
;' // -~-:J, ( "':"';" " .,"
;' " "J'y~' -.... ~ ....: ~.-.- ...' .
'It.. ~..... ... """:'" ... ... ~ :;:,.-,::;'-'- .
;: ;-1; ; : ::;'t-:-;.:.... SEAPLANE BASE
......:;,,~~.-.. :~/ LANDFILL
_/~~...;.()-~ (AREA 49)
... ....
--..../
/--
. For Location of 48/49.SW.6 See Inset
ili
.u.u
~
LEGEND
-+-
....
Groundwater Sample
Surfac!! Water Sample
DIrt Road
. O~
~~~
.' .. ~"\~
t£SG€
G~ .
-----
-----
. . 25 ....., Contour line
- . - . - Drainage Ditch
~'. Weiland
..
./0
400
SCALE IN FEET
CLEAN
COMPREHENSIVE
I.ONI1 TERM
EN ,'.i liAENTAl
ACnON N~'"
Figure 13
Area 48 and 49. Proposed Surface Water and Groundwater Sample Locations
eTO 0042
OPERABLE UNIT 4
NAS WHIDBEY, WA
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SEAPLANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89~D-9295
ero 0042
Record of Decision
Date: U/15/93
Page 59
environment nor does it meet state and federal regulations for Areas 39, 41, 44, and 48.
It does not remove or remediate potential contaminants detected in the surface soil or
sediment at OU 4 and, therefore, results in a risk to human health and the environment.
9.2
ALTERNATIVE 2: LIMITED ACflONS-AREAS 39, 41, 44, 48, AND 49
Limited actions are physical or administrative controls that could preven.t .or reduce
exposure to chemicals of concern on all of the areas. These actions do not reduce the
toxicity, mobility, or volume of contaminated soil or sediment. Limited actions proposed
are .the installation of fencing to prevent public access, warning signs, and drainage
devices to control sediment transport during storm events (sediment traps); restriction of
future land use; and monitoring and reponing on the contaminated soil and sediment iri .
the areas. For Areas 39, 41, 44, and 48, this remedy may not be applicable because off-
area migration of surface soils may still occur' by air or surface water transport. If and
wh~n the Navy transfers the Area 49 property to another owner, the deed will contain a
notification that the property contains a past construction and demolition debris landfilL
This alternative, with the exception of the Area 49 deed not~fication, can be commenced
within a IS-month period after the ROD is signed.
9.3
ALTERNATIVE 3: SOIL COVER-AREA 39
Soil cover for Area 39 was considered an appropriate method of limiting soil contact. .
around Building 49. The cover would coriSistof a 6-inch-tbick soil layer that is sloped
and vegetated to prevent erosion. The cover would be approximately 6,400 square yards
in area, covering all of Area 39, including the drainage ditch and swale. Institutional
controls' would have to be implemented to maintain the integrity of the cover and to
prevent its removal. Restrictions would have to be placed on th~ use of this area. There
would be a short-term impact on the flora and fauna at this area until vegetative cover
was replaced.
The soil cover was not considered applicable to Areas 41 and 44 because much of the
area is paved and each of the locations requiring remediation is less than 10 square
yards. At Area 48 a soil cover was not considered because of long-tenn oper~tions and
maintenance cost considerations.
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U.S. Navy CLEAN Contract .
Engineering Field Activity, Northwe~t
Contract No. N62474-89-D-9295
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This alternative could commence within a IS-month period aft~r the ROD is signed.
9.4
ALTERNATIVE 4: EXCAVATION, TRANSPORTATION, AND DISPOSAL (ON
STATION OR OFF-SITE, WITH OR WITHOUT STABILIZATION)-AREAS 39,
41, 44, AND 48
It is. a soil removal alternative that disposes of the excavated materials at a location .
depending on the classification of the material. Controls for dust and accidental release
of the excavated soils would be implemented during excavation. The excavated areas
would be filled with noncontaminated material and restored to preexcavation condition.
In the sumps and catch basins of Area 44, pumping equipment or hand removal would
be required to remove trapped sediments.
The excavated soils need to be characterized to ensure that they are disposed of in a
manner that is protective of human health and the environment and in compliance with
Washington State and federal' regulations. .
By federal and Washington State definition (40 C.F.R.~ 261.2 and WAC 173-303-
016(3)(a», these soils are contaminated media. The State of Washington requires
generators of solid waste to determine whether the waste is a "dangerous waste" or an
"extremely hazardous waste," using the procedures in WAC 173-303-070 through 103.
These procedures will be followed to characterize the soils removed during remediation
actions.
'If, through testing; it is determined that the excavated soils (and sediments for Area 44)
are classified as "dangerous waste" or "extremely hazardous waste," the excavated
materials from each area would be disposed of off site at an approved disposal facility.
If, on the other hand, the excavated material is not classified as, a "dangerous waste" or
"extremely hazardous waste," it would be disposed of at the on-station landfill (Area 6)
without stabilization. The on-station landfill is presently being closed, and OU 4 soils
would be used as subgrade material for the landfill cap.
The transfer. of this soil to Area 6 landfill at Ault Field will be done according to the
NCP. The preamble of the NCP states that when noncontiguous facilities are reasonably
close to one another .md wastes at these sites are compatible for a selected treatment or
disposal approach, CERCLA section 104(d)(4) allows the lead agency to treat these
related facilities as one site for response purposes and, therefore, allows the waste
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SEAPLANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295.
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Date: 12/15/93
Page 61
transferred between such noncontiguous facilities without having to obtain a permit
(FR 1407; 55 FR 8690-91).
This alternative can be commenced within a 15-month period after the ROD is signed.
The following general methodologies will be used for removal of soil (and, in Area 44,
storm drain sediments).
.
Area 39
Surficial soils (approximately 256 cubic yards) would be excavated (see Figure 9). Three
confirmatory soil samples would be taken from evenly spaced areas at the bottom of the
excavation of the southern swale and one sample each at the other areas of concern
. shown on Figure 9. The samples will be analyzed only for those constituents listed in
Table 13 for Area 39. In the event that chemical concentrations are below the remedial
action objectives listed in Table 13, excavation will stop and clean fill will be added to
the site: . '. .
Any sample location that exceeds the remedial action objectives will require further
excavation until these objectives are attained. The excavation will be backfilled with
clean soil. After filling operations are completed, the area will be graded to conform
with surrounding terrain, and revegetated.
.
Area 41
. Up to 5 cubic yards will be excavated from the edges of the ,Building 25 foundation
where remedial action. objectives were exceeded (see Figure 10). One 'confirmatory soil
sample will be taken from each of the two excavations and analyzed for the compounds
listed in Table .13 for Area 41. The excavations will be backfilled with clean soil. After
filling operations are completed, the area will be graded to conform with surrounding
terrain.
.
Area 44
Approximately 20 to 30 cubic yards of surface soils are to be excavated at the northern
edge of the old concrete apron and sediments are to be removed from the storm drain
sumps, catch basins, and manholes at Area 44 (see Figure 11). Surface soils with lead
and arsenic exceedances will be excavated to a depth of 1 to 2 feet. Two confirmatory
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SEAPLANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
cr00042
Record of Decision
Date: 12/15/93
Page 62
, soil samples will be taken from the excavation and analyzed for the compounds listed in
Table 13 for Area 44. The surface soil excavations will be backfilled with clean soil.
After filling operations are comp~eted, the area will be graded to conform with
surrounding terrain. Sediments from the storm drain will be removed until the sumps,
catch basins, and manholes are clean upon visual inspection.
.
Area 48
It waS agreed that a maximum of 1,000 cubic yards would be removed from Area 48,
from the triangle formed by 48/49-MW-5-1, 48/49-S-5, and 48/49-S-6 wells and soil
borings. The excavated area is 1,500 square yards; maximum depth is 2 feet. The area
of concern is shown in Figure 12. Three confirmatory soil samples would be taken from
evenly spaced areas at the bottom of the excavation. The samples will be analyzed for
those constituents listed in Table 13 for Area 48. The excavation will be filled to the
original height with clean fill, graded to conform with the surrounding terrain, and
revegetated. At the option of the Navy" the excavation may be used to form a wetland.
10.0 COMPARATIVE ANALYSIS OF ALTERNATIVES
The EP A has established nine criteria for the evaluation of remedial alternatives. The
four remedial action alternatives were evaluated against these criteria.
, .
The following section presents a brief discussion of each of the alternatives relative to
, the"evaluation criteria. '
10.1
PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT
The primary risk to human health and the environment is through direct contact or
ingestion of contaminants in the soils. Alternative 4 is considered protective of human
health and the environment because treatment or disposal in a landfill of contaminated
soils reduces the possibility of direct contact or ingestion or release to the surface water,
air, or groundwater. Alternative 3 prevents direct contact and ingestion of contaminants
in the soils at ,Area 39 by capping and reduces the possibility of release to the surface
water and air but not to _groundwater.
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SEAPlANE BASE, OPERABLE UNIT 4
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Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
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Date: 12/15/93
Page 63
Alternatives 1, and 2 would not adequately address this threat because the potential for
direct contact, ingestion, or releases to the surface water, air, and groundwater at au 4
would continue to exist at Areas 39, 41, 44, and 48. '
10.2
COMPLIANCE WIm ARARs
, Alternative 4 meets all federal' and state ARARs.
Alternatives 1, 2, and 3 for Areas 39, 41, 44, and 48 do not remove contaminated soil
that exceeds the State of Washington's MTCA Method B cleanup standards for direct
exposure to soils.
10.3
REDUCTION OF TOXICITY, MOBILITY, OR VOLUME THROUGH
TREATMENT ,.
, ,
Because of the volume of contaminated soil and the types of contaminants present,
treatment options were not found to be practicable and they were not considered in any
, of the alternatives.
Alternative 4 removes the soils from the site and disposes of the excavated material at
controlled landfills, where mobility is reduced. The volume of contaminated material is
reduced at OU 4; however, the toxicity of the soil is not reduced.
, ,
Alternative 3 reduces the mobility of contaDrlnants through contaimnent; however, it
does not reduce toxicity or volume. '
Alternatives 1 and 2 do not treat the contamination; therefore, this criterion is not met
by these alternatives. There is no reduction of toxicity or volume with either alternative.
10.4
SHORT-TERM EFFECTIVENESS
There are two basic considerations when evaluating alternatives for this criterion:
(1) whether the alternative creates human health or environmental concerns during
remediation and (2) the length of time the alternative takes to achieve the established
objectives.
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Contract No. N62474-89-D-9295
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Alternatives 1 and 2 do not create any adverse human health or environmental concerns
during remediation because they include only limited site activities. However, neither
alternative accomplishes the established objectives for Areas 39, 41, 44, and 48 of being
protective of human health and the environment.
Alternatives 3 and 4 effectively achieve established objectives in a short time period.
During remediation, some particulate emissions can be expected from excavation
activities in Alternative 4. However, dust control methods and careful implementation of.
site-specific safety protocols would effectively minimize these risks. No adverse effects. .
are anticipated from implementation of Altemative 3.
10.5
LONG-TERM EFFECTIVENESS AND PERMANENCE
Alternative 4 is both effective and permanent. With these alternatives, contaminated soil
is removed from the location where possible exposure could occur, to a permitted landfill
for waste disposal.. . . . .
Alternative 1 does not establish barriers to possible exposure to contaminated soil and
both Alternative 1 and 2 leave contaminated soil at the site following remediation.
Therefore, they are not considered effective in mitigating risks from the areas.
Alternative 3 is effective in creating a barrier (Le., the soil 'cover) to exposure, but the
cover could be disturbed, exposing the contaminated soils.
10.6 .IMPLEMENTABILITY
All alternatives are readily implementable. There are no known technical or
administrative barriers to any of the alternatives.
, 10.7
COST
The estimated capital and operations and maintenance costs for each alternative are
summarized in Table 14. Net present worth costs are also summarized and are based on
10 years of operations and an assumed annual discount rate of 5 percent. The cost
estimates provide an accuracy of + 50 percent to -30 percent, in accordance with EP A
guidelines.
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SEAPlANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract.
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0042
Record of Decision
Date: 12/15/93
Page 65
Table 14
Cost Comparison for Each Alternative by Area
~~~II~llrlirt.lli!ili.111~1::I'
j~mtr*~~~1~~m~rlii~»Jf:fl!~l:~!f mMMMtMB!:!!:ttlt:tWf mKmmrmm:~;n:::nmm ::::::nlmm:B~@jl::mm
1. No Action Capital Cost Capital Cost Capital Cost Capital Cost
SO SO SO SO
Annual O&M SO Annual O&M SO Annual O&M SO Annual O&M SO
Present Wonh SO Present Wonh SO Present Wonh SO Present Wonh SO
2. Limited Capital Cost Capital Cost Capital Cost Capital Cost
Action/ $94.000 510.000 SI0.000 SI8.000
Institutional Annual O&M Annual O&M Annual O&M Annual O&M
Controls $20.000 56.000 $6.000 SS.OOO
Present Wonh Present Wonh Present Worth Present Wonh
S2A8.000 SS9.000 SS9.000 SS7.000
3. Soil Cover Capital Cost NA NA NA
SJ.7oo
Annual O&M
SSOO
Presen't Wonh
51.800
4. Excavation. Off-Site
Transpon
a. Off-Site Capital Cost Capital Cost Capital Cost Capital Cost
Disposal with $232.000 SS,OOO $17.000 SS5O.000
Stabilization Annual O&M Annual O&M Annual O&M Annual O&M
SO SO SO SO
Present Worth Present Wonh Present Worth Present Wonh
S232.ooo SS.OOO $17.000 SS50.OOO
b. On-Station Capital Cost Capital Cost Capital Cost Capital Cost
Disposal $10.000 $2,000 $2,000 $39.000
without Annual O&M Annual O&M Annual O&M Annual O&M
Stabilization SO SO SO SO
Present Wonh Present Wonh Present Worth Present Worth
$10.000 $2,000 $2,000 539.000
Note:
NA = not applicable
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SEAPlANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract .
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0042 .
Record of Decision
Date: 12/15/93
Page 66
10.8 .STATE ACCEPTANCE
Ecology concurs with the selected remedial action at the Seaplane Base, and has been
involved in the development and review of the RI, FS, Proposed Plan, and ROD..
Ecology comments have resulted in substantive changes in these documents, and the
Agency has been integrally involved in determining which cleanup standards apply to
contaminated soil under MTCA.
10.9
COMMUNI1Y ACCEPTANCE
Comments received during the public comment period (August 15 through
September 16, 1993) indicate that the public accepted the Proposed Plan.
11.0 THE SELECTED REMEDIES
Based upon consideration of the requirements of CERCLA., the detailed analysis of the
. alternatives using the nine criteria, and public comments, both the EP A and State have
determined that Alternative 2 (deed restrictions) and Alternative 4 (excavation and on-
station or off-site disposal of excavated soils at a landfill) are the most appropriate
remedy for Operable Unit 4, Areas 39, 41, 44, 48, and 49 at the Seaplane Base.
The selected remedy for Area 49 is to place a notification of past construction and .
. demolitIon debris landfill on the deed when and if the Navy disposes of the property
. (Alternative 2). No COCS were detected above federal or state standards in this Area.
Although inorganic and organic chemicals were detected in groundwater, this
groundwater is not considered potable becaus~ of saltwater intrusion. The remedy
therefore meets state and federal regulatory standards. There are no costs, other than
normal administrative costs, for the implementation of this remedy.
Excavation of contaminated soils ~d on-station disposal at the Ault Field landfill in
Area 6 (Alternative 4) is the selected remedy for Areas 39, 41, and 48. This involves
removal and disposal of approximately 456 cubic yards of surface soil from Area 39, 5
cubic yards of shallow soils from Area 41, and approximately 1,000 cubic yards of surface
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SEAPLANE BASE, OPERABLE UNIT 4
U.s. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
era 0042
Record of Decision
Date: 12/15/93
Page 67
soil from Area 48. The estimated capital costs of this component of the remedy are:
Area 39, $10,000; Area 41, $2,000; Area 48, $39,000. There are no associated annual
O&M costs.
For Area 44, the selected re~edy (Alternative 4) is excavation, treatment if needed, and
off-site disposal at an approved landfill of 1 cubic yard of sediment and approximately 30
cubic yards of surface soil. The estimated capital cost of this component of the remedy
is $17,000. There is no associated annual O&M cost. . . .
The soil removal from Areas 39, 41, 44, and 48 will meet regUlatory soil cleanup
standards established under WAC 173-340 (MTCA) for .the COCs. MTCA cleanup
standards for individual chemicals correspond to a risk-based cancer risk of 10-6 and a
Hazard Index less than 1. The storm drain sumps, catch basins, and manhole in .Area 44
will be visually inspected to confirm that they are clean following removal of the
sediment. The removal will be conducted in compliance with WAC 173-303, which
governs tbe id~ntification and disposal of soils classified as dangerous waste.
. ..
Actual or threatened releases of hazardous substances from these Areas could present a .
potential threat to public health, welfare, or the environment. The removal of the
contaminated soils, which will be limited in scope and will be performed in compliance
with federal and state regulations, precludes any future water transport of these soils or
infiltration of leachate into the groundwater. It will allow unlimited use of these sites
with low uncertainty of risk to human health and the environment.
Alternative 4 complies with state and federal regulations and ARARs. It employs.. .
permanent solutions and treatment technologies to the maximum extent practicable in
achieving the best balance among the evaluation criteria of long-term effectiveness and
permanence, reduction in mobility through removal, short-term effectiveness, .
implementability, and cost. Because of the volume of aH:ected soil and tbe types of
chemicals present, treatment was not found to be practicable.
12.0 STATUTORY DETERMINATION
Under CERCLA, Section 121, the selected remedies must be protective of human health
. and the environment, comply with applicable or relevant and appropriate requirements,
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SEAPLANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0042
Record of Decision
Date: 12/15/93
Page 68
be cost effective, and u!ilize permanent solutions and alternative treatment technologies
or resource recovery technologies to the maximum extent practicable. In addition,
CERCLA includes a preference for remedies that employ treatment that permanently
and significantly reduces the volume, toxicity, or mobility of hazardous wastes as their
principle element. The following sections discuss how the selected remedy meets these
statutory requirements. Also, at some of the proposed locations for remedial action, the
Navy opted to remove soil to achieve its goal of unrestricted use of the Areas with no
future monitoring requirements.
12.1
PROTECfION OF HUMAN HEALTH AND THE ENVIRONMENT
The selected remedial actions will protect human health and the environment by
removing contamination from the site and disposing of the contaminated soil from
, Areas 39, 41, 44, and 48 in a controlled landfill. There are no critical habitats,
, threatened or endangered species, floodplains, or historical preservation sites within
OU 4 requiring consideration during the RIfFS process. '
12.2
COMPLIANCE WITH APPLICABLE OR RELEVANT AND APPROPRIATE
REQUIREMENTS
The selected remedy of soil removal will comply with all state and federal ARARs.
U.2.1 Action-Specific,
Hazardous Waste Management Act, 42 V.S.C. sec. 6901 et seq.; RCRA Subtitle C,40
C.F.R.$~ 260-268; Washington State Dangerous Waste Regulations, WAC 173-303'.
These regulati~ns designate waste as hazardous and establish standards for generators of
hazardous wastes for treating, storing, and shipping these wastes. This is applicable to
soils and sediments that are excavated and designated as hazardous waste.
The Clean Air Act, Section 101, 42 U.S.e. Sections 7405, 7601; Washington General
Regulations for Air Pollution Sources, WAC 173-400. These requirements are applicable
to sources of fugitive dust that are generated during the remediation efforts and must be
controlled to avoid nuisance conditions.
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SEAPlANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0042
Record of Decision
Date: 12/15/93
Page 69
Federal and State of Washington Occupational Safety and Health "Regulations 29
C.F.R.~ 1926, WAC 296-62 part P. These requirements establish applicable health and
safety standards for workers engaged in hazardous waste investigations.
Hazardous Materials Transportation Act, 49 C.F.R.~ 171-172. These regulations are
applicable to the transportation of potentially hazardous materials, including samples and
wastes.
12.2.2 Chemical-Specific
RCRA Subtitle C, 40 C.F.R.~ 261. This regulation is applicable in identifying if the. soil
excavated from the area is considered a hazardous waste for purposes of transporting
them off-site for treatment or disposal. .
Washington Model Toxics Control Act, WAC 173-340. This regulation is applicable
when establishing cleanup standards.
Washington Dangerous Waste Regulations, WAC 173-303. These regulations are
applicable in determining whether the soil excavated from the area is considered a
dangerous waste for purposes of transporting it off site for disposal or treatment.
12.2.3 Location-Specific
Coastal Zone Management Act, 16 D.S.C. sec. 1451 et seq. and Washington State
Shoreline Management Act of 1971, WAC 173~14. This requirement establishes
procedures applicable to construction work :that ocCurs within 200 feet of the shoreline. .
U.3
COST EFFECTIVENESS
For Areas 39, 41, 44, and 48, Alternative 4 is protective of human health and the
environment, and complies with ARARs. For Areas 39, 41, and 48, on-station disposal is
less costly than off-site disposal. . Area 44 surface soils and storm drain sediments are
likely to require off-site disposal with stabilization because of the high concentration of
lead in the soil. The quantity of material was too small for other alternatives to be
considered. The selected remedies provide an overall effectiveness proportional to their
costs, such that it represents a reasonable value for the' money that will be spent.
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SEAPlANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0042
Record of Decision
Date: 12/15/93
Page 70
For Area 49, Alternative 2 is protective of human health and the environment, complies
with ARARs, and can be implemented at the lowest cost compared to other alternatives.
12.4
UTILIZATION OF PERMANENT SOLUTIONS AND ALTERNATIVE
TREATMENT TECHN()WGIES OR RESOURCE RECOVERY
TECHNOLOGIES TO THE MAXIMUM EXTENT PRACTICABLE
The selected remedies represent the best balance of tradeoffs among the alternatives'
evaluated. They provide a high degree of permanence, use treatment to the maximum
extent practicable, do not negatively impact human health or the environment during
remediation, can be completed in a ~hort time, and are cost-effective.
The selected remedies were chosen primarily because they comply'with MTCA, an
applicable regulation.
. ,
The selected remedies meet the statutory requirements to use permanent solutions to the
maximum extent practicable. Treatment of sO,il from all areas, except the sumps and
catch basins of Area 44, is impr3.ctical. Concentrations of chemicals of concern do not
warrant treatment prior to disposal, except for lead levels from Area 44.
12.5
PREFERENCE FOR TREATMENT AS PRINCIPAL ELEMENT
Surface soils and, sediments from the storm drain system of Area 44 will be treated prior
to disposal if they are designated as dangerous or extremely dangerous waste. All other
excavated soil will be placed in a controlled environment, the. Area 6 landfill, which is
being closed. '
.-
13.0 DOCUMENTATION OF SIGNIFICANT CHANGES
The only significant change that has taken plaCe for this ROD is the combining of
Alternative 4 (excavation, transportation, and off-site disposal with stabilization) and
Alternative 5 (identical to Alternative 4 but with on-station disposal and no
stabilization). Alternatives 4 and 5 were presented in the Feasibility Study and Proposed
Plan. However, these alternatives weresimil~ enough to combine them in the ROD.
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SEAPlANE BASE, OPERABLE UNIT 4
U.s. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
era 0042
Record of Decision
Date: 12/15/93
Page 71
Alternatives 4 and 5 have been combined as a single alternative: Alternative 4,
Transportation and Disposal (On-Station or Off-Site With or Without Stabilization),
Areas 39, 41, and 48.
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»
SEAPLANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract
Engineering Field Activity, Nortbwest
Contract No. N62474-89-D-9295
era 0042
Record of Decision
Date: U/15/93
Page 73
A'ITACHMENf A
RESPONSIVENESS SUMMARY
OVERVIEW
Naval Air Station Whidbey Island Seaplane Base is located in Island County,
Washington, at the northern 'end of Puget Sound and the eastern end of the Strait of
Juan de Fuca. It is located on the northern portion of Whidbey Island, adjacent to the
City of Oak Harbor. Operable Unit 4 consists of five areas within the Seaplane Base.
These five areas are:
.'
.
Area 39: former Auto Repair and Paint Shop
Area 41: fonner Building 25 and Building 26 Disposal Area
Area 44:, former Seaplane Base Nose Hangar
Area 48: fonner Seaplane Base Salvage Yard
Area 49: fonner Seaplane Base Landfill
.
.
.
These areas of NAS Whidbey Island Seaplane Bas~ were placed on the NPL in February
1990.
Contaminated materials from Areas 39, 41, 44, and 48 will be'removed and disposed of
either at the Area 6 landfill or at an off-site landfill. The chemical concentrations of
both soils and sediments will be assessed in order to ,determine if the material should be
pisposed of on or off site. If chemical concentrations in the excavated materials are
classified as "dangerous waste" or "extremely hazardous waste," following the procedures
in WAC 173-303-070 through 103, they will be disposed of off site. In the event that
these materials, are not classified as "dangerous" or "extremely hazardous,".they will be
disposed of at the Ault Field Area 6 Landfill. No action will be taken at Area 49 except
to place wording in the deed when and if the Navy disposes of the property stating that
the area is the site of a previous construction and demolition debris landfill.
This responsiveness summary addresses public comments on the proposed plan for
remedial action at Operable Unit 4. The comments were submitted to the Navy during
the public comment period, which opened August 16, 1993, and closed September 15,
1993. .
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SEAPLANE BASE, OPERABLE UNIT 4
U.5. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0042
Record of Decision
Date: 12/15/93
Page 74
. ..
A public meeting was held on September 1, 1993, in Oak Harbor, Washington, at the
Chief Petty Officers' Club. No members of the general public attended and no
comments were received during the meeting. A transcript of the proceedings of the
public meeting is part of the administrative record. Two letters were received during the
public comment period. Comments are grouped according to similar concerns or
questions and addressed by topic area.
1.
RESPONSE TO COMMENTS ON RI/FS
No comments were received on the RI or FS reports.
2.
SUMMARY OF COMMENTS ON. PROPOSED PLAN
There were two letterS with comments on the proposed plan. The comments are
suriunarized. below, with responses.. . . .
Comment
One commenter agreed with the selection of Alternative 4, disposal of excavated
soils in Area 6 landfill, but recommended that excavated soils be properly placed
in the landfill, an appropriate cap be placed over the soils, and regional
groundwater issues for the Area 6 landfill be evaluated. .
.
Response
The soils and sediments excavated from OU 4 will be disposed of according to the
State of Washington's Dangerous WaSte Regulation, Chapter 173-303 of the
Washington State Administrative Code (WAC), Minimum Functional Standards
for Solid Waste Handling Chapter 173-304 (WAC), and Title 40 of the Code of
Federal Regulations (C.F.R.). A Minimum Functional Standard (MFS) cap will
be placed over the Area 6 landfill operations area. The MFS cap consists of a
50-mil flexible membrane liner underneath a layer of vegetated soil. This cap has
been chosen because it is a more effective leachate barrier than clay caps and it is
easily implemented. It is the standard cover required for closure of solid waste
landfills and is considered one of the more advanced capping techniques.
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D
SEAPlANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
COntract No. N62474-89-D-9295
CTO OM2
Record of Decision
Date: 12/15/93
Page 75
Area 6 groundwater issues are discussed in the Responsiveness Summary section
of the ROD for au 1. Groundwater in the shallow, intermediate, and deep
aquifers in Area 6 will continue to be monitored even after the MFS cap is in
place.
Comment
A second commenter requested more information on the impacts of Areas 39, 41~,
'and 44 on the adjacent Oak Harbor sediments. '
.
Response
Detailed information on the human health risks of offshore sediments adjacent to
Areas 39, 41, and 44 can be found in Section 6.0 of the Final Remedial
Investigation Report. The risk assessment conducted under CERCLA for the
RI/FS~ and described in this ROD, indicate that neither offshore sediments nor,
mussel ingestion pose' an unacceptable threat to human health or the '
environment.
, ,
Although some risk in consuming mussels was found, it was due to background
levels of arsenic. Further, the Puget Sound Estuarin~ Program study showed that
99 percent of the arsenic found in Puget Sound shellfish is in a nontoxic form.
Mussel consumption, therefore, does not represent an unacceptable risk. ,
Chemicals of concern were found in the marine sediments offshore of the Areas;
however, all were detected in concentrations significantly below cleanup, levels~
except at three stations. These three detections occtirred in the deepest sediments
and do not pose a problem because they are not in the biologically active zone.
Comment
A request was made to compare results from OU .4 with the Puget Sound
Environmental Atlas for Region 4.
.
Response
The concentrations of the organic compounds P AHs and PCBs, and of the metals
arsenic, cadmium, copper, mercury, lead and zinc detected in the remedial
investigation for the Seaplane Base were compared with the range of
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"
SEAPlANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
era 0042
Record of Decision
Date: .12/15/93
Page 76
concentrations provided in a publication called the Puget Sound Environmental
Atlas for Region 4, which presents water and sediment quality data for the entire
Puget Sound. The maximum concentration of copper (86.7 ppm) in subsurface
sediment in Area 44 is slightly higher than the concentration range in the Atlas
(less than 5Q ppm).
Lead was detected at 42.9 ppm in surface sediments and 151 ppm in subsurface
sediments in. Area 41. The lead concentration range provided in the Atlas was
less than 30 ppm. . . . .
All the other metals and the P AHs and PCBs were within the range of
concentrations provided in the Atlas.
A prohibited commercial shellfish growing area for Oak Harbor is shown in the
Atlas as well as a prohibited zone within one-half mile of the sewage outfall in
Crescent Harbor..
Comment
The second commenter also asked how the proposed remedies would comply with
any possible changes in the water quality or sediment standards.
.
Response
With all affected soils and sediments at OU 4 removed, no future impacts on the.
niarine' environment due to water transport .of these affected soils or infiltration of
leachate into the groundwater from these soils can occur. It should be noted that
the groundwater at OU 4 is not a source of drinking water.
If, in the future, site conditions change or if new information is discovered, the
operable unit can be reevaluated or Washington State can request the Navy to
take action and clean up an area.
Comment
The second commenter wanted to know what the potential impacts on tribal
people harvesting shellfish in the areas of Oak Harbor and Crescent Harbor
would be.
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SEAPLANE BASE, OPERABLE UNIT 4
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
era 0042
Record of Decision
Date: 12/15/93
Page 77
.
Response
The human health risk assessment determined that there is no human health risk
from ingestion of mussel tissue from either Oak Harbor or Crescent Harbor. The
risk assessment in the RI showed a risk in consuming mussels; however, this risk
is due almost solely to arsenic that was found at background levels. Further, the
Puget Sound Estuarine Program study showed that 99 percent of the arsenic
found in Puget Sound shellfish is in a nontoxic form. The ar~enic analysis was for
total arsenic, and it did not distinguish betWeen the toxic and nontoxic forms. A
subsequent evaluation, assuming that one percent of the arsenic found in mussels
is toxic, shows that of the mussel consumption up to 10 times the ingestion rate
evaluated in the RI is acceptable. .
.'
During the remedial investigation, it was determined that harvestable clams do
not appear in Oak Harbor and Crescent Harbor; they were found only at Polnell
and Forbes Point. ~ese findings have been verified by the Island County Health
Depanm~nt. . . ..
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