EPA/ROD/R10-94/077
July 1994
EPA Superfund
Record of Decision:
N.A.S. Whidbey Island
(O.U. 2), Oak Harbor, WA
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I !
DECLARATION OF THE RECORD OF DECISION
SITE NAME AND LOCATION
Naval Air Station Wbidbey Island, Ault Field
Operable Unit 2, Areas 2/3, 4, 14, and 29
Oak Harbor, Island County, WashiDgton
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial actions for Operable UniqOU) 2 (Areas 2/3, 4, 14,
and 29) at Naval Air Station (NAS) Wbidbey Island, Ault Field, a Superfund site near Oak Harbor,
Washington. au 2 is one of four operable units at NAS Wbidbey. The remedies selected were developed
in accordance with the Comprehensive Environmental Response, Compensation, and Liability Act of 1980
(CERClA), as amended by the Superfund Amendments and Reauthorization Act (SARA), and, to the
extent practical, the National Oil and Hazardous Substances Pollution Contingency Plan (NCP). This
decision is based on the admini!:trative record for au 2.
The lead agency for this decision is the United States Navy (Navy). The United States Environmental
Protection Agency (EPA) approves of this decision and, with the WashiDgton State Department of Ecology
(Ecology), has participated in scoping the site investigations and in evaluating altematives for remedial
action. The state of Washington concurs with the selected remedy.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from au 2, if not addressed by implementing the
response action selected in this Record of Decision (ROD), may present an imminent and substantial
endangerment to public health, welfare, or the environment
DESCRIPTION OF THE SELECTED REMEDIES
The selected remedial actions at Operable Unit 2 at NAS Whidbey Island, Ault Field, address the threats
posed at the site by providing for surface soil removal, institutional controls, and groundwater monitoring.
These actions will reduce the mobility of contamination and limit human exposure. The elements of the
remedial action iBclude:
.
Groaadwater Monitoring. At Areas 2/3, 4, and 29, groundwater may cootain metals exceeding
background and health-based levels. Groundwater will be monitored for.metals at these areas using
low-stress sampling methods. If contaminatioo is confirmed, the Navy, EP A, and Ecology will
determine what additional action, if any, is necessary.
.
Area 2/3. Implementation of institutional controls and groundwater monitoring for metals and
volatile organic compounds.
.
Area 4. Removal of approximately 1,750 cubic yards of PCB-contaminated surface soil north of the
location of the former Walker Barn. The excavated soil will be transported to a permitted off-site
h3Zaldous/dangerous waste disposal facility. The excavation will be bac1dil1ed with clean soil and
reseeded.
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.
Area 14. Pumpout, treatment, and disposal of water (approximately 1,000 gallons) from" a dryweU
used for pesticide riDsate disposal and from a nearby monitoring well south of Building 2555
fonowed by removal of both wells and associated dioxm-coDtamiDated soil (approximately 420 cubic
yards). The soil excavated from the area will be transported to a permitted off-site
hazardous/dangerous waste disposal facility. The excavatiOD will be backfilled with clean soil and
reseeded. The grouodwater in the immediate vicinity of the dryweU will be monitored in the wet
SeasoD to confirm that remedial actioD was successful. "
.
Area 29. Removal of approximately 1,400 cubic yards of P AH-CODtaminated surface soil west of the
intersectioD of Clover Valley Road and Golf Course Road. The excavated soil will be disposed of
on base at the Area 6 landfill The excavatiOD may be left opeD to create a wetland.
STATUTORY DETERMINATIONS
The selected remedies protect human health and the enviroomeDt, comply with federal and state
requirements that are legally applicable or relevant and appropriate to the remedial actions, ~d are cost-
effective. These remedies use permanent Solutions and alternative treatmeDt technologies to the maximum
extent practical for this site. However, beca~ of the low volume of CODtaminated soil and the types of
COIJIt~mnu'nts present, treatment was Dot found to be practical. Therefore, these remedies do Dot satisfy the
statutory prefereDce for treatmeDt as a principal element of the remedy. CODtamiDated soil will be removed
from the site and properly m~nS\8"'.d. A S-year review will be required for the Area 2/3 landfill and
potentially for Area 14 if source removals are Dot effective.
;/
3QS4O\9403.1a7\TEXT
11
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Signature sheet for the Naval Air Station Wbidbey Island, Awt Field, Operable Unit 2, Record of Decision
betWeen the United States Navy and the United States Environmental Protection Agency, with concurrence
by the Washington State Department of Ecology.
---S-~-::r:5~
~ ( z...!. q -4
Date
Captain John F. Schork
Commanding Officer
Naval Air Station Whidbey Island
United States Navy
30S40\94a3.107\TEXT
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f
Signature sheet for the Naval Air Station Whidbey Island., Ault Field., Operable Unit 2, Record of Decision
betWeen the United States Navy and the United States Environmental Protection Agency, with concurrence
by the Washington State Department of Ecology.
eL//L M~
Chuck Clarke
Regional Administrator, Region 10
United States Environmental Protection Agency
5)-":f Jq~
Date
30S40\9403.107\TEXT
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Signature sheet for the Naval Air Station Whidbey Island, Ault Field, Operable Umt 2, Record of Decision
between the United States Navy and the United States Environmental Protection Agency, with concurrence
by the Washington State De~ent of Ecology.
. &~~j'
Carol Kraege
Acting Toxies Cleanup Program Manager
Washington State Department of Ecology
30S40\9403.107\TEXT
. fr7'A!
Date .. (
.
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AULT FIELD, OPERABLE UNIT 2
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N6247~89-D-9295
era 0054
-Fmal Record of Decision
Date: 04/2fJ/94
Pageix
CONTENTS
Section No.
Page No.
DECLARATION OF THE RECORD OF DECISION. . . . . . . . . . . . . . . . . . . . . . .
ABBREVIATIONS AND ACRONYMS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. xv
1.0 IN1:RODUCI10N .......................................,....... 1
2.0 SITE NAME, LOCATION, AND DESCRIPTION. . . . . . . . . . . . . . . . . . . . . .. 1
2.1 AREA 2: WESTERN HIGffiANDS LANDFILL .............,. 4
2.2 AREA 3: 1969-TO-1970 LANDFILL ...,..................... 4
2.3 AREA 4: WALKER BARN STORAGE AREA . . . . . . . . . . . . . . . .. 6
2.4 AREA 14: PESTICIDE RINSA1E DISPOSAL AREA . . . . . . . . . . .. 6
25 AREA 29: CLOVER VAU..EY FIRE SCHOOL................ 6
3.0 SITE mSTORY AND ENFORCEMENT ACI1VlTIES .................. 6
4.0 COMMUNTI'Y RELATIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11
5.0 SCOPE AND ROLE OF OPERABLE UNITS ........................
13
6.0 SUMMARY OF SITE CHARACIERISTICS """""""""""'" 13
6.1 -" HYDROGEOLOGIC SETI'ING . . . . . . . . . . . . . . . . . . . . . . . . . . .. 13
6.2 NATIJRE AND EXTENT OF CONTAMINANTS. . . . . . . . . . . . .. 18
6.2.1 Soil and Sediment. . . . . . . . . . . . . . . . . . . .: . . . . . . . . . . . .. 18
6.2.2 Groundwater...................................... 21
6.2.3 Surface Water. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 26
7.0 SUMMARY OF SITE RISKS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 28
7.1 HUMAN HEAL1H RISKS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 28
7.1.1 Exposure Assessment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 29
-" - 7.1.2 Toxicity Assessment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 32
7.1.3 Risk Characterization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 36
7.1.4 Uncenainty..."..."................................. 43
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AULT FIELD, OPERABLE UNIT 2
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0054
Final Record of Decision
Date: 04/26/94
Page x
CONTENTS (Continued)
Section No.
Page No.
72
ECOLOGICAL RISK ASSESSMJ;:NT . . . . . . . . . . . . . . . . . .-.. . . .. 44
72.1 Exposure Assessment. . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. 44
7.22 Toxicity Assessment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 45
72.3 Risk Characterization. . . . . . . . . . . . . . . . . . . . . . . . . ; . . . .. 45
7.2.4 Uncertainty....................................... 47
RISK ASSESSMENT CONCLUSIONS. . . . . . . . . . . . . . . . . . . . . .. 48
73
8.0 REMEDIAL ACTION OBJECTIVES (RAOs) ........................ 48
8.1 SOIL. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 50
8.2 GROUNDW A 'fER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 52
83 SURFACE W A 'fER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 53
9.0 DESCRIPTION OF AL'fERNATIVES .............................. 53
9.1 AL'fERNATIVE 1: NO ACTION-AREAS 2/3, 4, 14, AND 29 . . .. 54
92 AL'fERNATIVE 2: INS1ITUTIONAL CONTROLS-AREAS 2/3
. AND 29 ............................,.................. 54
9.3 ALTERNATIVE 3: EXCAVATION, TRANSPORTATION, AND
OFF-SI1"E DISPOSAL-AREAS 4, 14, AND 29 ................ 54
9.4 ALTERNATIVE 4: EXCAVATION, TRANSPORTATION, AND
ON-BASE DISPOSAL-AREAS 4,14, AND 29 ........... '" . ., 61
9.5 ALTERNATIVE 5: EXCAVATION, TRANSPORTATION, AND
OFF-SI1"E INCINERATION-AREAS 4,14, AND 29..... . . .. .. .. 61
9.6 ALTERNATIVE 6: CAPPING THE AREAS-AREAS 2/3, 4,
AND 29 ............................................... 62
9.7 ALTERNATIVE 7: SOIL COVER-AREA 29 .........:...... 63
9.8 ALTERNATIVE 8: LANDFARMING-AREA 29 . . . . . . . . . . . . .. 63
10.0 COMPARATIVE ANALYSIS OF ALTERNATIVES.................. 64
10.1 PROTECTION OF HUMAN HEALrn AND THE
ENVIRONMENT. . . . " . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 64
. 102 COMPUANCE WITH ARARs . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 64
103 RErfnctION OF TOXICITY, MOBILITY, AND VOLUME
THROUGH TREATMENT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 65
10.4 SHORT-TERM EFFECTIVENESS. . . . . . . . . . . . . . . . . . . . . . . . .. 66
30540\9403.107\TEXT
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. I
AULT FIELD, OPERABLE UNIT 2
U.s. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0054'
. . Final Record of Decision
Date: 04/26/94
Page xi
CONTENI'S (Continued)
Section No.
Page No.
10.5 LONG-TERM EFFECTIVENESS AND PERMANENCE......... 66
10.6 IMPLEMENT ABilITY ................... ~ . . . . . . . . . . . . .. 67
10.7 COST................................................ 67
10.8 STATE ACCEPTANCE.......................... ..,..... 67
10.9 COMMUNITY ACCEPTANCE.................... ..... .., 69
11.0 SELECTED REMEDIES AND CLEANUP LEVELS. . . . . . . . . . . . . . . . .. 69
11.1 1HE SELECTED REMEDIES. . . . . . . . . . . . . . . . . . . . . . . . . . . .. 69
11.1.1 Area 2/3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 69
11.12 Area 4 .................""""""""""""" 70
11.1.3 Area 14 ......................................... 71
11.1.4 Area 29 ......................................... 71
12.0 STATUTORY DE1ERMINATION . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . .. 72
12.1 PROTECTION OF HUMAN REALTII AND 1HE
ENVIR.ONMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 72
122 COMPLIANCE WI1H APPUCABLE OR RELEVANT AND
APPROPRIATE REQUIREMENTS (ARARs) ................. 73
122.1 Action-Specific ARARs . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 73
12.22 Chemical-Specific ARARs . . . . . . . . . . . . . . . . . . . . . . . . . . .. 74
12.2.3 Location-Specific ARARs ............................ 74
122.4 Other Criteria, Advisories, or Guidance. . . . . . . . . . . . . . . . .. 74
123 COST EFFECTIVENESS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 75.
12.4 UTlllZATION OF PERMANENT SOLUTIONS AND
ALTERNATIVE TREATMENT TECHNOLOGIES OR
RESOURCE RECOVERY TECHNOLOGIES TO THE
MAXIMUM EXTENT PRACTICAL. . . . . . . . . . . . . . . . . . . . . . .. 75
12.5 PREFERENCE FOR TREATMENT AS PRINCIPAL ELEMENT.. 76
13.0 DOCUMENTATION OF SIGNIFICANT CHANGES.................. 76
AITACHMENT A
RESPONSIVENESS SUMMARY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. A-I
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Final Record- of Decision
Date: 04/26/94
Page xii
AULT F1ELD, OPERABLE UNIT 2
U.S. Navy CLEAN Contract
Eogineering Field Activity, Northwest
Contract No. N62474-89-~-9295
ero 0054
FIGURES
Figure No.
Page No.
'4
5
6
7
1
2
3
NAS Whidbey Island Location Map. . . . . . . . . . . . . . . . . . . . . . . . . --' . . . . .. 2
Operable Unit 2 Area Locations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3
Area 2 (Western Highlands Landfill) and Area 3 (1969-to-1970 Landfill)
- Site Map. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . '- . . . . .. 5
Area 4 (Walker Barn Storage Area) Site Map. . . . . . . . . . . . . . . . . . . . . . .. 7
Area 14 (Pesticide Rinsate Disposal Area) Site Map. . . . . . . . . . . . . . . . . .. 8
Area 29 (Oover Valley Fire School) Site Map. . . . . . . . . . . . . . . . . . . . . . .. 9
Groundwater Potentiometric Surface Contours of the Intermediate Aquifer
for Areas 2/3 and 29 .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Surface Water Drainage Patterns Around OU 2 . . . . . . . . . . . . . . . . . . . . . .
Area 2/3-Spatial Distribution of COCS Detected in Surface Soil. . . . . . . . .
Area 4-Spatial Distribution of COCS Detected in Surface Soil. . . . . . . . . .
Area 14-Spatial Distribution of COCS Detected in Surface Soil and
Groundwater. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .' 59
Area 29-$patial Distribution of COCs Detected in Surface Soil. . . . . . . . .. 60
8
9
10
11
12
TABLES
Table No.
Page No.
1
2A
2B
3
4
Chemicals of Concern in Soil and Sediment. . . . . . . . . . . . . . . . . . . . . . . . .
Chemicals of Concern in Groundwater Total (Unfiltered) Samples. . . . . . . . -
Chemicals of Concern in Groundwater Dissolved (Filtered) Metals. . . . . . . .
Chemicals of Concern in Surface Water. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Populations, Media, and Routes of Exposure Evaluated at Areas 2/3''-'4, 14,
and 29 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exposure Point Concentrations for Chemicals of Greatest Significance for
the Human Health Risk Assessment at OU 2 . . . . . . . . . . . . .. . . . . . . . . . . .
Toxicity Valu~~ for Chemicals of Potential Concern. . . . . . . . . . . . . . .. . . .
Area 2/3-Summary of RME Noncancer and Cancer Human Health Risks .
Area 4-Summary of RME Noncancer and Cancer Human Health Risks. . .
Area 14-Swnmary of RME Noncancer and Cancer Human Health Risks. .
Area 29-Summary of RME Noncancer and Cancer Human Health Risks. .
Chemicals Posing Potential Risks to Terrestrial Organisms at Lower
Trophic Levels. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5
6
7
8
9
10
11
30S40\9403.107\TEXT
16
17
56
57
19,
22
24
27
30
33
35
38
39
40
41
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AULT FIELD, OPERABLE UNIT 2
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
era 0054.
Final Record of Decision
Date: 04/26/94
Page xiii
12
13
14
Remedial Goals Selected for Soils at OU2 . . . . . . . . . . . . . . . . ... . . . . . . . .
Decision Criteria for Groundwater at OU2 .........................
Estimated Costs of Remedial Alternatives. . . . . . . . . . . . . . . . . . . . . . . . . .
51
53
68
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I I
AULT FIELD, OPERABLE UNIT 2
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0054
Fmal Record of Decision
Date: 04/26/94
Page xv
ARAR
bgs
CERCLA
COC
COPC
CSR
DoD
Ecology
EFANW
ELCR
EPA
EPC
FFA
HEAST
In
HQ
HRS
!AS
IRIS
IRP
LDR
MCPP
MFS
mgjkg
msl
MTCA
NACIP
NAS
NAVFACENGCOM
NCP
NPL
O&M
30S40\9403.107\TEXT
ABBREVIATIONS AND ACRONYMS
applicable or relevant and appropriate requirement
below ground surface
Comprehensive Environmental Response, Compensation, and
Liability Act of 1980
chemical of concern
chemical of potential concern
current situation report
United States Department of Defense
Washington State Department of Ecology
Engineering Field Activity, Northwest
excess lifetime cancer risk
United States Environmental Protection Agency
exposure point concentration
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
land disposal restriction
Mecoprop
Minimum Functional Standards
milligrams per kilogram
mean sea level
Model Toxies Control Act (Washington 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
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AUL T FIELD, OPERABLE UNIT 2
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89.D-9295
era 0054
Final Record of Decision
Date: 04/26/94
Page xvi
ABBREVIATIONS AND ACRONYMS (Continued)
OU
PAH
PCB
PCP
POlW
ppb
ppm
RA
RAO
RCRA
RfC
RID
RI/FS
RME
ROD
SARA
SF
SVOC
TAL
TBC
TCLP
TSCA
UCL
USGS
VOC
WAC
operable unit
polycyclic aromatic hydrocarbon
polychlorinated biphenyl
pentachlorophenol
publicly owned treatment works
parts per billion
parts per million
risk assessment
remedial action objectives
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 .
toxic characteristics leaching procedure
Toxic Substances Control Act
upper confidence limit .
United States Geological Survey
volatile organic compound
Washington Administrative Code
"
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f I
AULT FIELD, OPERABLE UNIT 2
U.s. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0054
. Final Record of Decision
Date: 04/26/94
Page 1
DECISION SUMMARY
1.0 INTRODUCI'lON
Under the Defense Environmental Restoration Program, it is the United States Navy's
(Navy) policy to address environmental 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
has the approval of the United States Environmental Protection Agency (EP A) and the
concurrence of the Washington State Department of Ecology (Ecology) and is responsive
to the expressed concerns of the public. The selected remedial action will comply with
applicable or relevant and appropriate requirements (ARARs) promulgated by the EPA,
Ecology, and other federal and state agencies.
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 naval air station is divided into two facilities-the Seaplane Base and
Ault Field. Ault Field is located at the northern end of the island, north of the city of
Oak Harbor (population 14,000). Ault Field is divided into four operable units (OUs);
this Record of Decision (ROD) addresses OU 2, which consists of. five study areas
(Figure 2):
. Area 2: Western Highlands Landfill
. Area 3: 1969-to-1970 Landfill
. . Area 4: Walker Barn Storage Area
. Area 14: Pesticide Rinsate Disposal Area
. Area 29: Clover Valley Fire School
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NAS WHIDBEY
ISLAND
WASHINGTON
I
..................
.
.
.
.
.
.
__..1
.
.._..~
CITY OF
OAK HARBOR
_......_..-.........._.._..~
, .
'.
.
.
.
.
.
.
.
.
SEAPLANE BASE
~i
o
1
I -
Scale In Miles
CLEAN Figure 1 CTOOO54
OPERABLE UNIT 2
COMPREHENSIVE LONG- NAS Whidbey Island NAS WHIDBEY. WA
TERM ENVIRONMENT At Location Map RECORD OF DECISION
ACTION NAVY
r"'\
f"'\
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)
)
)
..
-
AREA 29
.;.:;. .
o
800
I
....!
SCALE IN FEET
CLEAN
COMPREHENSIVE
LONG-TERM.
ENVIRONMENTAL
ACTION NAVY
Figure 2
Operable Unit 2 Area Locations
CTO 0054
OPERABLE UNIT 2
NAS WHIDBEY, WA
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AULT FIELD, OPERABLE UNIT 2
U.S. Navy CLEAN Contract
. Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0054
Final Record of Decision
Date: 04/26/94
Page 4
Because of their similar nature and proximity, Areas 2 and 3 were considered together
(as Area 2/3) throughout the remedial investigation/feasibility study (RI/FS) and this
ROD.
No housing is located in the immediate vicinity of the areas addressed in this ROD.
There is military housing approximately one-third of a mile south of Area 14 and one
private residence approximately one-quarter of a mile southeast of Area 29. The base
hospital is located about 300 yards to the north of Area 4. The properties adjacent to
the areas addressed in this ROD include a wetland, the current fire training school, the
station recycling center, and the station golf course.
2.1
AREA 2: WESTERN HIGHLANDS LANDFILL
Area 2 (Figure 3) is a 13-acre former landfill located southwest of the current fire
training school. From 1959 to 1969, the landfill was the principal disposal area for solid
wastes from NAS' Whidbey. The landfill received industrial wastes and construction and
demolition debris. Currently the surface of the landfill is covered with soil and .
vegetated. The site is situated on a topographic high of 118 feet above mean sea level
(msl) and slopes eastward. The western boundary of Area 2, which is covered with
mixed evergreens, slopes toward the Strait of Juan de Fuca. A gravel road and a fence
define the southern boundary of Area 2. A wetland is located near the eastern boundary
of the site.
2.2
AREA 3: 1969-TO-1970 LANDFILL.
Area 3 (Figure 3) is a IS-acre parcel located east of Area 2 and southeast .of the current
fire training school. Area 3 was used for disposal of solid wastes betWeen 1969 and 1970.
Materials disposed of at Area 3 are similar to those at the Area 2 landfill. The landfill
is covered with soil and is currently vegetated. The site is situated on a small knoll
approximately 94 feet above msL Several remnant house foundations are present at the
south end of the knoll, .and an evergreen forest is located to the nonh. The ground
slopes to the west and south, into the wetland east of Area 2.
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)
)
)
-......-.-
AREA 3
LANDFILL ///'
//
,
LEGEND
. tlml\! 01 Invesllgation
@ Seasonal We«end
Dirt Road
........UJO....... Elevalfon ConIOUf line
(ft above msll
---K- Fence line
Drainage Ditch
i
-------
AULT FIELD, OPERABLE UNIT 2
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0054
Final Record of Decision
Date: 04/26/94
Page 6
2.3
AREA 4: WALKER BARN STORAGE AREA
Area 4 (Figure 4) is located approximately 400 yards west of Saratoga Street in the
southwest-central part of Awt Field. The current fire training school is located to the
southwest, and the Navy hospital is approximately 300 yards to the north (se~ Figure 2).
A gravel parking lot is located on the site of the former Walker Barn in the southern
portion of the area. Area 4 is flat, partially covered with native grasses, and
approximately 240 feet wide and 440 feet long. The area is currently fenced. .
2.4
AREA 14: PESTlCIDt RINSATE DISPOSAL AREA
Area 14 (Figure 5) is an approximately 0.5-acre fenced parcel located immediately south
of Building 2555 and west of Langley Boulevard. Pasture lands are adjacent to the
southern and western boundaries of Area 14. A cirywell was installed on the north-
central edge of the area in 1973. The drywell is located near an intermittent creek that
originates from a spring in the northwestern corner Of the area and flows southeastWard
through Area 14, toward Langley Boulevard.
2.5
AREA 29: CLOVER VALLEY FIRE SCHOOL
Area 29 (Figure 6) consists of a 4-acre parcel located west of the intersection of Clover
Valley Road and Golf Course Road in the southwestern portion of Ault Field. The site
is bordered by evergreen trees to the west, the Navy golf course to the south, Clover
Valley Road to the north, and Golf Course Road to the east. A 1,600-square-foot
concrete pad is located in the center of the area. A small ditch extends northeastWard
from the concrete pad to a ditch along Clover Valley Road. This ditch eventually flows
into the wetland betWeen Areas 2 and 3. .
"
3.0 SITE HISTORY AND ENFORCEMENT ACTMTlES
NAS Whidbey Island was commissioned in 1942. The station was placed on reduced
operating status aCtlie- end of World War ll. In December 1949, a continuing program
to increase the capabilities of the station was initiated. The station's current mission is
-------
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CLEAN
COMPREHENSIVE
lONG.TERM
ENVIRONMENTAL
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Area 4 (Walker Barn Storage Area)
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1.1
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Seal. 10 Feel
eTO 0054
OPERABLE UNIT 2
HAS WHIDBEY. WA
-------
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SCALE IN FEET
CLEAN Figure 5 eTO 0054
COMPREHENSIVE OPERABLE UNIT 2
LONG-TERM Area 14 (pesticide Rinsate Disposal Area) NAS WHIDBEY. WA
ENVIRONMENTAL Site Map RECORD OF DECISION
ACTION NAVY
-------
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CLEAN
COMPREHENSIVE
LONG-TERM
ENVIRONMENTAL
ACT10N NAVY
, Figure 6
Area 29 (Clover Valley Fire School)
Site Map
CTO 0054
OPERABLE UNIT 2
HAS WHlDBEY, WA
-------
AULT FIELD, OPERABLE UNIT 2
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0054
rmal Record of Decision
Date: 04/26/94
Page 10
to maintain and operate Navy aircraft and aviation facilities and to provide associated
support.
Since the 1940s, operations at NAS Whidbey Island have generated a variety of
hazardous wastes. These wastes were disposed of using practices that were ~onsidered
acceptable at the time.
In response to the requirements of CERCLA, the United States Department.of Defense
(DoD) established the Installation Restoration Program (IRP). Responsibility for the
implementation and aitmin;~tration of the IRP has 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.
In September 1984, the Navy conducted an initial assessment study (!AS) at NAS
Whidbey Island. The !AS consisted primarily of a records review. A more detailed
report, the NAS Wbidbey Island Current Situation Report (CSR), was completed by the
Navy in January 1988.
In late 1985, EPA proposed that both Ault Field and the Seaplane Base be nominated to
. the National Priorities List (NPL) as separate sites. In February 1990, both sites were
officially listed on the NPL, based on the following 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
In response to the NPL designation, the Navy, the 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 Whidbey Island.
-------
AULT FJELD, OPERABLE UNIT 2
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract ~o. N62474-89-D-9295
era 0054
. . Final Record of Decision
Date: 04/26/94
Page 11
Following CERCLA and SARA guidelines, various sites and areas at NAS Whidbey
Island were later grouped into operable units. Operable units designate specific areas
undergoing the RIfFS process. Five areas at Ault Field (Areas 2, 3, 4, 14, and 29) were
collectively identified as OU 2. The purpose of the associated RIfFS was to characterize
the site, determine the nature and extent of cOI!tamination, assess human and ecological
risks, and evaluate remedial alternatives.
4.0 COMMUNITY RELATIONS
The RI, FS, and proposed plan were released to the public in November 1993. These
documents were made available to the public in both the admini~trative record and at
the information repositories listed below.
Oak Harbor Library
7030 70th N.E.
Oak Harbor, Washington 98278
I:'hone: (206) 675-5115
Sno-Isle Regional Library System
Coupeville Library
788 N. W. Alexander
Coupeville, Washington 98239
Phone: (206) 678-4911
For anyone' with access to NAS Whidbey Island:
NAS Whidbey Island Library
1115 West Lexington Street
Oak Harbor, Washington 98278
Phone: (206) 257-2702
-------
AULT FIELD, OPERABLE UNIT 2
U.s. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
era 0054
Fmal Record of Decision
Date: 04/26/94
Page 12
The admini"trative record is located at:
Engineering Field Activity, Northwest
Naval Facilities Engineering Command
1040 N.E. Hostmark Street
Olympic Place 1
Poulsbo, Washington 98370
Phone: (206) 396-5984
The U"~i1ing address for the admini"trative record is:
Engineering Field Activity, Northwest
Naval Facilities Engineering Comm~lnd
3505 N.W. Anderson Hill Road
Silverdale, Washington 98383
Commnnity relations for the Ault Field OU 2 investigation included:
.
Creating a community relations plan based on community interviews
conducted in 1991 (finalized January 10, 1992)
.
Meeting with representatives from the public and from other governmental
agencies (Under the auspices of the Technical Review Committee)
.
Issuing the final proposed plan (on November 10, 1993) with newspaper
advertisement .
.
Meeting with the public (on December 1, 1993) to present the final
proposed plan ..
'"
In accordance with Section 117(a) of CERCLA as amended by SARA, the proposed plan
for OU 2 was released to the public through the Whidbey News Times on November 10,
1993. The public comment period was from November 12 to December 12, 1993. A
public meeting to present the proposed plan to concerned citizens was held at the Chief
Petty Officers' Club on Ault Field Road on December 1, 1993, at 7:00 p.m. Two
members of the press and four interested citizens attended, along with representatives
from the Navy, the EPA, and Ecology.
-------
I
AULT FIELD, OPERABLE UNIT 2
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0054 .
Final Record of Decision
Date: 04/26/94
Page 13
One comment was received by the Navy at that meeting concerning the proposed plan.
No written comments were received on the proposed plan. The single comment is
snmm~Tized in the Responsiveness Summary (Attachment A) appended to this Record of
Decision.
5.0 SCOPE AND ROLE OF OPERABLE UNITS
NAS Whidbey Island comprises two main facilities, Ault Field and the Seaplane Base.
Potential source areas at NAS Whidbey Island have been grouped into separate OUs, for.
wbich different schedules have been established. There are four operable units at Ault
Field and one operable unit at the Seaplane Base. This Record of Decision addresses
only au 2 at Ault Field. Remedies have already been selected for au 1 at Ault Field
and au 4 at the Seaplane Base (RODs were signed in December 1993). Oeanup
actions will be selected later in 1994 for OU 3 and OU 5 (Ault Field).
The remedial actions at Ault Field address soil and on-site groundwater contamination
detected above established state and federal health-based and regulatory levels. Surface
soils at Areas 4, 14, and 29 are the only environmental media requiring active
remediation. Groundwater actions are limited to monitoring at Areas 2/3, 4, and 29 to
confirm that no further action is required and at Area 14 to affirm the effectiveness of
remediation. The cleanup actions described in this ROD address all known current and
potential risks to human health and the environment associated with the au 2 site.
6.0 SUMMARY OF SITE CHARACl'ERISTICS
This section presents a snmmary of site conditions, including a discussion of tbe geologic
and hydrogeologic characteristics and the nature and extent of contaminants.
6.1
HYDROGEOLOGIC SETTING
Wbidbey-Island lies within the Puget Sound Lowland, a topographic and structural
depression between the Olympic Mountains and the Cascade Range. Previous
investigations have reponed that unconsolidated geologic units on Whidbey Island consist
-------
AULT FIElD, OPERABLE UNIT 2
U.5. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0054
F'mal Record of Decision
Date: 04/26/94
Page 14
of a sequence of Quaternary-age (less than 2 million years old) glacial and interglacial
deposits. These deposits may be as much as 3,000 feet thick in the southern ponion of
the island, but are relatively thin in the north, where bedrock is present near the surface.
The near-surface deposits on Whidbey Island are believed to have been laid down during
the Fraser glaciation between 10,000 and 20,000 years ago.
Features of the glacial stratigraphy on northern Whidbey Island and NAS Whidbey
Island have been described from surficial exposures and borehole samples during
regional geologic studies and site-specific environmental investigations. The general
regional stratigraphy of northern Whidbey Island consists of the following geologic units,
listed from youngest to oldest:
Recent deposits: sand, silt, and clay
Everson gladomarine drift: clayey silt to silty clay
Vashon recessional outwash: sand and gravel
Vashon till: gravelly, sandy silt
Vashon advance outwash: clean to silty sand and gravel
Whidbey formation: sand, silt, peat, and clay
Metamorphic bedrock: bedrock .
Geologic units encountered during the au 2 investigation have been correlated to the
Everson glaciomarine drift, the Vashon till, the Vashon outwash, and bedrock.
As many as five regional aquifers have been identified on Whidbey Island by tbe United
States Geological Survey (USGS) (Units A through E, from oldest to youngest). These
waterbearing units do .not directly correlate to distinct geologic units, but rather may
comprise part of a single or of multiple geologic units. The aquifers are generally
composed of sands and gravels deposited by glacial meltwaters, separated by aquitards
made up of fine-grained silts and clays deposited as glacial till, glaciomarine sediments,
or nonglacial lake deposits.
The intermediate aquifer (correl~.ting to the USGS Hydrogeologic Unit D) was the only
regional waterbearing unit encountered dining the OU 2 investigations.
Three perched groundwater zones were encountered above the regional water table
beneath au 2. Discontinuous, low-permeability clay layers within the vadose zone above
the Vashon advance outwash deposits, at depths ranging from about 15 to 25 feet below
ground surface (bgs), intercept downward-percolating water, creating localized perched
-------
J I
AULT FIELD, OPERABLE UNIT 2
U.s. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0054
Final Record of Decision
Date: 04/26/94
PagelS
groundwater conditions. Perched conditions were encountered on the west side of Area
2, on the south side of Area 3, and in the central portion of Area 29. These perched
zones appear to be independent of one another. Water levels in wells installed in the
perched groundwater zones showed seasonal variations in excess of 4 feet. Higher water
levels were measured during the w~t winter months and lower levels during the dry
summer season.
The moderately continuous intermediate aquifer consists of a sandy unit that is typically
confined throughout much of Whidbey Island. The aquifer is made up of sands and
gravels within the Vashon outwash unit. This waterbearing unit is present beneath most
of Ault Field (including au 2), except for parts of Clover Valley, at depths ranging from
about 50 to 100 feet bgs. Groundwater within this unit occurs under artesian conditions
where the waterbearing sands are confined by the overlying low-permeability Everson
drift deposits. Where this unit has been eroded, groundwater occurs under unconfined
conditions. Potentiometric surface elevations within this unit range from about 10 to 75
feet above IDSI beneath OU 2.
Groundwater witJrin the intermediate aquifer flows generally westward toward the Strait
of Juan de Fuca (Figure 7), although the flow direction has a northerly component in
Area 3, a southwesterly component in Area 4, and a northeasterly component in Area
29. The groundwater flow direction at Area 14 is generally to the south.
Using the range of hydraulic conductivities and gradients measured at the OU 2 sites,
calculated groundwater velocities beneath the area range locally from less than 1 foot
per year to over 2,500 feet per year.
The surface water runoff over most of OU 2 flows primarily eastward, through
engineered drainage ditches along roads, toward the Ault Field ;runway area (Figure 8).
In Areas 2 and 3, the surface runoff flows into the wetland between these two areas.
Area 4 is considered to have minim~ I surface runoff because of the high infiltration rate
of the top 2 to 3 feet of soil, which consists of sandy gravels with a dense layer of till
below that prevents water movement. The surface runoff for Area 14 moves toward an
intermittent creek that flows south through the area. In Area 29, the surface runoff
flows from the old fire pad northeast along a small ditch and then parallels Clover
Valley-Road.
-------
JL L.LJ L:
lCE
~
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Strait of
Juan de Fuca
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.
SCAL£ IN fET
CLEAN Figure 7 . CTOOO54
OPERABLE UNIT 2
COMPREHENSIVE lONG- Groundwater Potentiometric Surface Contours of the NAS WHIDBEY. WA
TERM ENVIRONMENTAl Intermediate Aquifer for Areas 2/3 and 29 RECORD OF DECISION
ACT10N NAVY
'"
-------
)
)
)
-
o
'I
Noee: DuguaJla Bay 1& located to the east
(not'hoWn).
iN "~:j
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SCALE IN FEET
CLEAN
COMPREHENSIVE
LONG. TERM
ENVIRONMENTAL
ACTION NAVY
Figure 8
Surface Water Drainage Patterns Around OU 2
CTO OOS4
OPERABLE UNIT 2
NAS WHIDBEY. WA
-------
AULT FIELD, OPERABLE UNIT 2
U.s. Navy a..E.AN Contract
EDgineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ere 0054
Final Record of Decision
Date: 04/26/94
Page 18
All the drainage ditches merge at the runway area; the flow is then diverted eastward to
a diked lagoon in Cover Valley and subsequently pumped into Dugualla Bay. The most
westerly portions of Ault Field drain directly into the Strait of Juan de Fuca. During the
winter and spring, most of the freshwater wetlands in and around NAS Whidbey Island
are flooded. There is generally no surface runoff during the dry summer and fall months
except as a result of intermittent storms. .
6.2
NATURE AND EXTENT OF CONTAMINANTS
Surface and subsurface sou, sediment, groundwater, and surface water samples were
analyzed for volatile organic compounds (VOCS), semivolatile organic compounds
(SVOCs), pesticides, polychlorinated biphenyls (PCBs), and target analyte list (TAL)
inorganics at all the OU 2 areas. At Area 14, where former activities included disposal
of pesticide rinsate solutions, additional analyses for dioxins and furans were performed.
Background concentration levels for inorganics were established from soil and
groundwater samples collected at OU 2 outside the areas of suspected contamination.
There are many ways to investigate landfills and to document the nature and extent of
cont~min~tion. At Area 2/3, geophysical surveys (electromagnetic and magnetic) were
. used to delineate the landfill boundaries and locate buried debris. Soil vapor surveys
were also used to identify the extent of the landfill and areas of contamination. Rather
than characterizing the landfill contents by sampling into the landfill, the impact that
these contents have on the environment was investigated by sampling groundwater,
surface water, soil, and sediments within and downgradient of the site.
The fonowing paragraphs describe the nature and extent of contamination for chemicals
of concern (COC) identified in soil, groundwater, freshwater sediment, and surface water
for each area. coe are defined as chemicals that exceed human health and ecological
risk threshold concentrations based on federal or state criteria. Inorganic chemicals
detected at or below background concentrations are not considered COe.
,.
6.2.1 Soil and Sediment
Table 1 lists the COC for soil and sediment, including the concentration range and
frequency of detection for each. The background concentrations of inorganic coe are
included for comparison.
-------
AULT FIELD, OPERABLE ,UNIT 2
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0054
Fmal Record of Decision
Date: 04/26/94
Page 19
Table 1
Chemicals of Concern in Soil and Sediment
- :::::::~i::;:!!::~!::;;::;;:::::::!::::::i:::::::;f_~.::::::::::~:::!::::::::::::i~::~:::::::::::~:::\:i::::::;:: . -
i!:I~I'i.I:11 !:.:'I:II":111:11 ::::11'.::1111:
2/3 Antimony 43 115 16.0 20/47 8.16
Arsenic 0.53 34.6 3.75 50/56 7.54
Beryllium 024 1.6 0.59 18/56 0.52
Cadmium 0.30 8.8 3.98 16/56 0.83
Lead 0.55 805 24.5 55/56 15.60
4 Antimony 3.5 53.7 16.1 9/35 8.16
Arsenic 1.0 9.6 3.9 29/35 7.54
Cadmium 0.47 8.6 2.99 23/35 0.83
Copper 52 2,790 103 35/35 442
Lead 0.91 796 44.7 34/34 15.6
Mercury 0.04 12.7 3.41 5/34 0.11
Zinc 1JJ.7 693 89.5 35/35 100.1
Benzo(b }fluoranthene 0.013 0.650 0.173 4/18 N/A
Chryscne 0350 0.350 0.350 1/18 N/A
MCPP 133 133 133 1/8 N/A
PCB Aroclor 1260 0.009 220 20.0 27/80 N/A
Pentachlorophcnol 3.6 1,300 655 3/20 N/A
14 Beryllium 0.40 1.4 0.77 20/47 0.52
PCB Aroclor 1260 0.95 9.4 5.18 2/49 N/A
2,3,7,8-TCDD 7.5xlO""' ppb 0.134 ppb 0.028 ppb 5/18 N/A
29 Arsenic 0.69 26.0 4.73 92/92 7.54
Beryllium 0.20 4.1 0.58 36/89 0.52
Cadmium 036 9.9 3.98 49/92 0.83
Lead 23 206 18.8 93/93 15.6
Benzo(a}anthracenc 0.010 18.0 2.48 - 20/93 N/A
Benzo(a}pyrene 0.007 26.0 3.52 23/93 N/A
Benzo(b }fluoranthenc 0.004 31.0 2.92 34/93 N/A
Benzo(k}f1uoranthenc 0.004 13.0 129 29/93 N/A
ChryseDe 0.027 22.0 2.69 12/93 N/A
2,4-Dmitrotolulene 3.704 3.704 3.709 1/35 N/A
Indeno(1.2,3-c(i)pyrene 0.036 17.0 3.06 16/93 N/A
P..entachlorophcnol 0.180 19.0 8.73 7/75 N/A
-Mean of detections
"Detections/number of samples collected
N / A = Not applicable. BaCkground levels were not determined for organic chemicals.
ppb = parts per billion
Note:
Chemicals of concern were identified as those chemicals exceeding federal and state threshold concentrations.
-------
AULT FIELD, OPERABLE UNIT 2
U.s. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0054
Fmal Record-of Decision
Date: 04/26/94.
Page 20
.
Area 2/3
Antimony, arsenic, beryllium, cadmium, and lead were detected above background
concentrations and above risk-based criteria in soil and sediment samples collected from
Area 2/3. There was no definable pattern or spatial distribution of the inorganic
analytes in the surface or subsurface soil.
.
Area 4
Antimony, arsenic, cadmium, copper, lead, mercury, and zinc were detected above
background concentrations in soils from Area 4 and at levels exceeding risk-based
criteria. Lead was detected in the upper 2 inches of soil. No other pattern or spatial
distribution of inorganic analytes could be determined.
PCB Aroclor 1260 and pentachlorophenol (pCP), a semivolatile organic compound, were
detected iri surface soil samples collected north of the former Walker Barn, where
transformers were stored PCB Aroclor 1260 was primarily detected in the surface soils,
but was found at depths up to 15 feet in two locations. Pentachlorophenol was detected
at three locations in the upper 1 foot of soil. The source of the PCP may have been the
electrical power poles, which were treated with wood preservatives, that are stored in the
area. Two polycyclic aromatic hydrocarbons (P AHs), benzo(b )fluoranthene and
chrysene, were detected above state cleanup levels. The P AHs may have come from the
fire training school currently operating approximately 100 yards southwest of Area 4.
The chlorinated herbicide Mecoprop (MCPP) was detected in one sample collected
3 feet bgs at monitoring well4-MW-3,which was drilled within the former Walker Barn
foundation.
.
Area 14
At Area 14, beryllium, PCB Aroclor 1260, and a dioxin, 2,3,7,8-TCDD, were detected in
the surface soils at concentrations above risk-based criteria. There was no definable
pattern or spatial distribution of beryllium detected in the soil. The beryllium
concentrations fell within the range of background concentrations and, therefore, may be
associated with naturally occurring levels. PCB Aroclor 1260 was detected in soil boring
samples collected from 14-SB-3 at 1 foot and 19 feet bgs. The detection of PCB ArocIor
1260 at 19 feet bgSiS believed to result from surface material that inadvertently entered
the boring during drilling. The dioxin, along with some furan congeners at lesser
-------
I
AULT FIELD, OPERABLE UNIT 2
U.s. Navy CLEAN Contract
EDgineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0054
- Fmal Record of Decision
Date: 04/26/94
Page 21
concentrations, was detected at one location, monitoring well 14-MW-1. Monitoring well
14-MW-l was installed just downgradient from the drywell.
.
Area 29
. -
Arsenic, beryllium, cadmium, and lead were detected at concentrations above risk-based
criteria in Area 29 soils. As at the other areas, there was no definable pattern or spatial
distribution of inorganic analytes in the soil either horizontally or vertically. Six
carcinogenic P AHs (benzo( a)anthracene, (benzo( a)pyrene, benzo(b )f1uoranthene,
benzo(k)fluoranthene, chrysene, and indeno(1,2,3-cd)pyrene) and two SVOCs (PCP and
2,4-dinitrotoluene) were also detected at concentrations above risk-based criteria.
Generally, these compounds were found to extend from the burn pad in a northeasterly
direction. P AHs were principally detected in the upper 1 foot of soil and were the most
frequently detected organic compounds. -
6.2.2 Groundwater
During the first phase of sampling, unfiltered groundwater samples were collected using
standard bailing techniques and analyzed for organics and total metals content. The
samples were cloudy and Contained high concentrations of inorganic metals, probably as
a result of suspended sediment. During the second phase of sampling, a number of
filtered metals samples were collected from selected wells along with the standard total
metals samples. In most cases, the filtered samples contained dissolved metals at much
lower concentrations than the concentrations of total metals in the unfiltered samples.
An insufficient number of dissolved samples were collected to determine dissolved
background concentrations. The following paragraphs discuss RI results for both the
total and dissolved metals samples.
Tables 2A and 2B show cae for groundwater for each area. Tah1e ZA presents values
for total (unfiltered) samples, including both inorganics and organics. Table 2B presentS
values for filtered (dissolved) samples analyzed only for inorganics (metals).
.
Area 2/3
Antimony, arsenic, beryllium, cadmium, chromium, lead, manganese, nickel, and
vanadium-were detected at concentrations above risk-based criteria in groundwater
samples analyzed for total metals. Filtered samples were collected for six monitoring
wells. In these samples, only antimony, arsenic, and manganese were identified as
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Page 22
Table 2A
Chemicals of Concern in Groundwater
Total (Unfiltered) Samples
:m~~~~: :;::::::::: ..1iIiIIIii -
.111[11111:
... "."""';""'"'""':"';':',. ..
2/3 Antimony 41.3 1Zl 66.4 14/50 20.47
Arsenic 1.4 63.5 13.7 48/50 16.24
Beryllium 2.0 6.0 3.5 4/50 0.50
Cadmium 5.0 20.4 10.1 5/50 0.50
Chromium 4.7 199 57.4 36/50 84.6
Lead 1.4 75.1 22.6 25/50 9.7
MaDganese 13.0 7,540 1,170 SO/SO 560
N"u:kel 4.9 333 91.2 38/50 157.1
Vanadium 3.6 251 58.3 25/50 57.6
Bis(2-ethylhexyl)
phthalate 1.0 96 12 16/49 N/A
I,4-Dichlorobenzene 1.3 3.7 2.3 4/50 N/A
.
Vmyl Chloride 0.46 30 19 3/50 N/A
4 Antimony 82.0 82.0 82.0 1/7 20.47
Arsenic 72 22.3 11.5 7/7 1624
Cadmium 4.0 9.4 6.7 2/7 0.50
Chromium 12.2 318 139 4/7 84.6
Lead 6.0 79.2 2£,.4 5/7 9.7
MaDganese 84.0 3,730 1,010 7/7 560
Nickel 10.0 461 147 6/7 ., 157.1
Tballium 1.3 1.3 1.3 1/7 0.17
Vanadium 12.3 368 150 4/7 57.6
Zinc 17.0 7,780 1,870 6/7 3532
14 Bromac:il 8.6 6,800 2,300 3/11 N/A
1,1-Dichloroethane 1.3 1.3 1.3 1/5 N/A
2,4-Dichlorophenol 2,800 2,800 2,800 1/5 N/A
Naphthalene... - 2.5 1,000 500 2/5 N/A
29 Antimony 9.0 58.4 38.3 3/12 20.47
Arsenic 3.5 53.2 16.9 11/12 1624
Beryllium 4.0 28.0 16.0 2/12 0.50
Chromium 12.9 941 167 8/12 84.6
Lead 3.6 102 28.8 6/12 9.7
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Table 2A (Continued)
Chemicals of Concern in Groundwater
Total (Unfiltered) Samples
.Mean of detections
"Detections/number of samples collected
N / A = Not applicable. Background levels were not determined.
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Table 2B
Chemicals of Concern in Groundwater
Dissolved (FIltered) Metals
:::::~.: '::':::~::::$~~»-;~::: :::~:::~:~~::~:::~~::~::~:::~j~~~~j~~~~jjj~j11jj~~~j~l1j~11~i1~~~j~~j~~~ =:1 -
:.:.:-:. "",;.:..:
:::::::. ...
..
.. '. .. :'~':':':':':':'."':':':':':':':'.'.'. ".. ,.. ..
2/3 Antimony 38.0 72.2 58.2 4/6 N/A
Arsenic 4.7 9.6 7.1 4/6 N/A
Beryllium NO NO NO 0/6 N/A
Cadmium NO NO NO 0/6 N/A
Chromium 3.4 3.4 3.4 1/6 N/A
Lead 2.4 7.6 5.1 3/6 N/A
MaDganese 7.0 284 115 6/6 N/A
Nickel 10 10 10 1/6 N/A
Vanadium 15.9 15.9 15.9 1/6 N/A
4 Antimony 10.6 10.6 10.6 1/3 N/A
Arsenic 3.0 93 6.6 3/3 N/A
Cadmium NO NO NO 0/3 NfA
Chromium NO NO NO 0/3 N/A
Lead NO NO NO 0/3 N/A
Mlln~nese 320 139 95.7 3/3 N/A
Nickel 10.2 10.2 10.2 1/3 N/A
Thallium NO NO NO 0/3 N/A
Vanadium 2.7 2.7 2.7 1/3 N/A
Zinc 29.0 29.0 29.0 1/3 N/A
14 No Fdtered Samples Collected
29 Antimony NO NO NO 0/3 N/A
Arsenic 3.2 7.7 5.5 2/3 ., N/A
Beryllium ND ND ND 0/3 N/A
Chromium NO NO NO 0/3 N/A
Lead 2.2 2.2 2.2 1/3 N/A
Manganese 107 424 269 3/3 N/A
Nickel 11.8 48.0 29.8 2/3 N/A
Vanadium 2.0 2.0 2.0 1/3 N/A
-Mean of detections
bpetections/number of samples collected
N/A = Not applicable. Background levels were not determined.
ND = Not detected above the analytical detection limit.
30S4G\9403.107\TA.BLE..2B
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contaminants of concern. The organic compounds detected above risk-based criteria in
total samples were bis(2-ethylhexyl) phthalate, 1,4-dichlorobenzene, and vinyl chloride.
Vinyl chloride was detected once in Area 2 and twice in Area 3. In both areas, the vinyl
chloride was detected only in the perched aquifer, not in the intermediate aquifer below.
.
Area 4 .
. Antimony, arsenic, cadmium, chromium, lead, manganese, nickel, thallium, vanadium,
and zinc were detected at concentrations above risk-based criteria in groundwater
samples analyzed for total metals. Filtered samples were collected from three of the
four Area 4 monitoring wells; only arsenic and manganese were identified as potential
cae in the filtered samples. No organic compounds were identified as cae in
groundwater samples from Area 4.
.
Area 14
No inorganic analytes were detected above risk-based criteria in the first encountered
groundwater at Area 14. Bromacil, l,l-dichloroethane, 2,4-dichlorophenol, and
naphthalene were detected above risk-based screening concentrations in one monitoring
well immediately downgradient of the drywell. These compounds either were not
detected or were detected below risk-based screening concentrations in the other wells at
Area 14.
One aqueous sample was taken from water that had collected in the drywell at Area 14;
the sample contained the herbicide bromacil and the dioxin 2,3,7,8-TCDD at
concentrations above risk-based criteria.
.
Area 29
Antimony, arsenic,. beryllium, chromium, lead, manganese, nickel, and vanadium were
detected above risk-based criteria in unfiltered groundwater samples analyzed for total
metals at Area 29. In filtered groundwater samples collected from three of the four
monitoring wells, only arsenic and manganese were identified as potential cae. The
only organic compound detected above risk-based criteria was PCP (detected in one well
upgradient of the burn pad).
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6.2.3 Surface Water
Chemicals identified as COC in surface water are shown in Table 3. Background
concenttations were not established for comparison against surface water concentrations.
In most locations, sediment samples as well as surface water samples were collected.
The following paragraphs summarize surface water COG for each area. .
. .
Area 2/3
Arsenic, cyanide, lead, and bis(2-ethylhexyl) phthalate were detected at concentrations
above federal and state criteria. The detection of inorganic analytes in various surface
water samples appears random and does not indicate a potential upstream source.
Arsenic, cyanide, and bis(2-ethylhexyl) phthalate were detected at estimated
concenttations near the detection limit in three samples, each primarily in the wetlands
between Area 2 and Area 3. Lead was detected in seven of eight samples, with each
detection exceeding federal and state criteria.
.
Area 4
Arsenic, chromium, copper, and lead exceeded risk-based criteria in one surface water
sample collected from the wetlands downgradient of Area 4. Zinc exceeded risk-based
criteria in one surface water sample collected from the wetlands upgradient of Area 4.
.
Area 14
Arsenic, chromium, copper, and zinc were detected at concenttations above risk-based
criteria in one surface. water sample collected downgradient of the drywell. Lead
exceeded risk-based criteria at all three surface water sampling stations.
.
Area 29
Arsenic, cadmium, copper, lead, and zinc were detected at concentrations above risk-
based criteria, as were one carcinogenic P AH, benzo(b )fluoranthene, and an SVOC,
bis(2-ethylhexyl) phthalate. All of the inorganic analytes were detected in one of the
three samples collected immediately downgradient of the burn pad.
Benzo(b )fluoranthene Was detected in all three surface water samples collected at Area
29. Bis(2-ethylhexyl) phthalate was detected in one surface water sample located
downgradient of the burn pad.
30S40\9403.107\TEXT
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Table 3
Chemicals of Concern in Surface Water
N.,",',',",",...,',,',.,", - .......... .,...... 0.,. ... ..... """",...," ..,.. '" .." "...,".,...."." ,". .....,... ... .... ....... n. ... n.. ""... .. ... .
.::':::;:::;::;::::::::!:~::::.:::::::~I::::::::~:i_l:::::::::~~::::::::::::::::::j:::::::::::::::::::~ ',.""'"'''''''''''''''''''''' '''P''''''''''''''''''''''''--'' .. ..
~~ ~~j~ ~~ 1j~1 rj~1j i~1~ 1j~j~ ~ij~~ ,',',',',',',",',',',','..,','.",'.'.',-,',','.',',",'.',",". .:.:.:.:.:.:.:.:.:.:.:.;.:.:.;.:.:.:.:.;.;.:.:~.;.:-:.:.;.;.:.;.:.;.;.:.;.;.;
"...............,..............
. '::I:.'.~"lli~1
::::::::~::::::;;:::::;:::;:::::;::: :,'::':11\1,11:111 .....1:;,8;;.....::1 :::.1:)::81:1:1111,1
I~::illill~~: :II:)H~:::(~}::m~:::::);,;}
2/3 Arsenic 2.0 2.9 2.4 3/8 N/A
Cyanide 4.7 7.4 6.1 3/8 N/A
Lead 2.8 47.7 11.8 7/8 N/A
Bis(2-ethylhexyl) 4.0 11 6.7 3/8 N/A
phthalate
4 Arsenic 2.0 2.0 2.0 1/3 N/A
Chromium 16.2 16.2 16.2 1/3 N/A
Copper 6.7 163 11.5 2/3 N/A
Lead 2.6 6.6 4.6 2/3 N/A
Zinc 10.0 245 104 3/3 N/A
14 Arsenic 2.4 2.4 2.4 1/3 N/A
Chromium 23.5 23.5 23.5 1/3 N/A
Copper 8.7 32.9 16.9 3/3 N/A
Lead 2.6 10.4 5.7 3/3 N/A
Zinc 119 119 119 1/3 N/A
29 Arsenic 10.6 10.6 10.6 1/3 N/A
Cadmium 5.8 5.8 5.8 1/3 N/A
Copper 103 103 103 1/3 N/A
Lead 572 572 572 1/3 N/A
Zinc 154 154 154 1/3 N/A
Beuzo(b )fluoroanthene 0.04 033 0.14 3/3 N/A
Bis(2-ethylhexyl) 4.0 4.0 4.0 1/3 N/A
phthalate
aMean of detections
br>etections/number of samples collected
N/A = Not applicable. Background levels were not determined.
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7.0 SUMMARY OF SITE RISKS
The baseline risk assessment (RA) provides an analysis of both current and potential
future risks for a site and is used to evaluate whether remedial action is needed. It
serves as the baseline to indi<:a:te what risks could exist if no action were taken at the site
and if existing land use patterns were to shift to full-time residential or occupational use
of the site. The primary components of the risk assessment include identification of the
chemicals of concern, exposure assessment, toxicity assessment, and risk characterization.
This section of the ROD reports the results of the baseline risk assessment conducted for
OU2. .
Both human health and ecological risk assessments were performed for OU 2 to
determine the potential risks associated with chemicals identified at the site. The human
health assessment was generally conducted in accordance with EP A's Risk Assessment
Guidance for Superfund, Volume I: Human Health Evaluation Manual (Part A), Region
10 Supplemental Risk Assessment Guidance, and Human Health Evaluation Manual,
Supplemental Guidance: Standard Default Exposure Factors. Groundwater was evaluated
on a site wide basis as compared to a clustering approach. The ecological risk
assessment followed the latest federal guidance. The RA methods and results are
S11mm~nized below.
7.1
HUMAN HEALTH RISKS
The human health RA evaluated potential risks associated with exposure to - ch~mical
contaminants from OU 2. All chemicals that were detected at least once were
considered in the risk assessment. An initial screening was performed to compare the
maximum detected concentrations of chemicals in soil and groundwater with background
concentrations (inorganics only) and risk-based screening concentrations developed by
EP A Region 10. (For groundwater, the risk-based screening concentration designated by
EP A represents a 1
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potential concern, or COpc. (The COPC are different from those chemicals identified
as cae in Section 6.2, which are those chemicals that exceeded a 1~ cancer risk or a
noncancer hazard index (HI) of 1 or that exceeded state standards.)
The cancer risks summarized in this report represent those risks at or above the upper
end (1~) of EPA's acceptable risk range. However, the entire lerto 10-4 risk range was
considered in the evaluation of the risks.
The RA considered potential exposure to chemicals from the groundwater, surface water,
and soil and from the ingestion of plants, meat, and dairy products grown on site.
Inhalation of volatile chemicals released into indoor air while showering and inhalation
of particulates in oUtdoor air were also evaluated. Three exposure scenarios were
evaluated for au 2: current recreational, future occupational, and future residential.
Potential exposures to both children and adults were evaluated under the recreational
and the future residential scenarios.
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,
the potentially exposed populations (based on current and future land uses), and the
routes of exposure and by quantifying human intake of chemicals. Table 4 presentS the
populations, media, and routes of exposure that were evaluated for each area.
.
Exposed Populations
Both current and potential future land uses were considered in identifying potentially
exposed populations. The same populations were evaluated for each area at au 2.
These potentially exposed populations include recreational visitor's, future workers. and
future residents. Risks have been calculated for both average exposures and for a
reasonable maximum exposure (RME). The RME corresponds to the highest plausible
degree of exposure that may be anticipated at a site.
.
Exposure Media and Pathways
Because-of the similar nature of the sites at au 2, the same media were evaluated for
each of the areas. The media that were quantitatively evaluated in the human health
risk assessment include soil, groundwater, surface water, vegetables, beef, and dairy
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Table 4
Populations, Media, and Routes of Exposure Evaluated
at Areas 2/3,4, 14, and 29
NO
YES
YES
NO
Soil
GrouadwateT
YES
YES
YES
YES
YES
YES
YES
YES
NO
YES
YES
YES
NO
YES
YES
NO
Surface wateT
Food
YES
NO
YES
NO
NO
NO
Notc5:
NO = Patbway aot evaluated
YES = Patbway evaluated
- = Patbway is Dot applicable to this receptor.
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products. Although a limited number of sediment samples were collected from several
of the areas, these sedimentS were not significantly different from native soils and were
evaluated in the risk assessment as if they were soil samples.
Although residential use of groundwater was evaluated, there is currently no residential
groundwater development at OU 2, and these exposures are strictly hypothetical. For
each area, groundwater risks were calculated using data from unfiltered groundwater
samples. When data were available (Areas 2/3, 4, and 29), risks resulting from
residential use of groundwater containing dissolved (filtered) inorganics were also
evaluated. A perched aquifer exists at Area 2/3, but its extent is so limited that it was .
not considered a potential drinking water source in the risk assessment.
Surface water from the wetland between Areas 2 and 3, seasonally ponded water at
Areas 4 and 29, and surface water in the Area 14 drainage ditch were evaluated only for
the recreational exposure scenario. Recreational contact with surface water by children
could be considered a potential exposure route under the future residential scenario.
HQwever, because this route was considered in tbe current recreational scenario and no
significant risks were found, the route was not re-evaluated for future residents.
The following pathways were evaluated for each media of concern:
.
Soil:
Ingestion, dermal contact, and inhalation of suspended
particulates
.
Groundwater: -
Ingestion, inhalation of volatiles, and dermal contact
while bathing
.
Surface water:
Ingestion and dermal contact .
.
Food chain: Ingestion of vegetables, beef, and dairy products .
.
Exposure Point Concentrations
Exposure point concentrations (EPCs) are those concentrations of each chemical to
which an individual may potentially be exposed for each medium at the site. For
CERCI:A risk assessments, the EPC is intended to be an upper-bound representation of
the average site concentration, such as the 95 percent upper confidence limit (VCL) on
the mean (95 percent UCL). If, however, the 95 percent VCL exceeds the maximum
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detected concentration, then the maximum concentration is used instead. The 95 percent
UCL was used to represent the EPC for all chemicals at au 2.
Table 5 presents the EPCs for those chemicals whose calculated risk at au 2 exceeded
.EPA's acceptable risk range (i.e., a cancer risk greater than 10-' or a noncancer hazard
quotient greater than 1) and those chemicals that, when added together, posed a cancer
risk greater than 1
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Table 5
Exposure Point Concentrations for Chemicals of Greatest Significance
for the Human Health Risk Assessment at OU 2
::i:~:@.~!:f::ii::::::::i:::::i:::i::::::::i:tr:::::::::::::::;:;::M:::i::i::::::::::::l:':;:@f::;:::::::;::!:1::::::::f;f:::i:::@::i::tI:::;;:::::::::::::::::::::::i:n::i:::::i:n:::::::i::r:i::::trr:::::::::::f:jJ::::n:,::::::;::i::::r:1ii::;;:::::i:::::::::r:::;:::J!i::;:f;:;:i:;r:::{::::::;::::::i;{::::::::::::i
W!~::::::::::::tm::::::j:::;::W:::::::::i:I:::::::l)::::tr::::::::(:::,::::::::J:::!:::::j:::::::::::::m:;:::i~t::i:::::::i:::::m:tjt:::Ii::::II:t::::::;:::::':::::::~):,:t:::t::::::::;:::i::::::l:I:::m::::::::::::::::::t::::::::(p~~:::m:j::i::::::I'J:mm::::;
Antimony 10.6 22.9 115
Arsenic 4.7 7.6 34.6
ii:!:"i~I~~I'i!:i:!'li:ili::;'II!I..ii'I.:~!'!I'li':lill;.I'I":I:'!:J'",:,::..'.,~i:...:!:'::il~\II'ii;!:I:1:.11:,11'1111.:.11111.111.1;
Antimony. 24/34
Arsenic 13/6
1.170/110
r$,!~::::::m:m:::t}::t'i:ir;:::':::i:j:::;'i\:::::::::::rm:':mijtj:::':::H:::;:=t:::::::::m:::!::::::::::::!iP@)':::r:=:::ij:j:!=::j::::;::r::=::::t'::=::::j}=:::t::::::i;hm~):;r:::=;::{:::=::n=::::i=;:i:=::::=t::I::{=I=:,'\':(ili*I):)iF?:::{::::';::;::::
Antimony 6.1 . 11.9 53.7
Arsenic 5.1 63 9.6
Lead 73.4 158.0 796
MCPP 18.8 49.8 133
PCB Aroclor 1260 20.2 38.9 220
ill!._.~I:I:'!.lllil:.III!.II'i':III;;!I",!'i'III.1!IIHil!ill.i.::I!:lillil:::'I..II.lil.":I:~I~:::I!:il'il;'III'.:I:I:I.I:;.!IIII!:!I:I:
Antimony 19/ND
Arsenic' 12/5
1,000/127
i~~::;~~~~~i::{::;:::::i:i::::::t:::::::::i::=:i::::::=t:ri:=:i::i:!:(ijli~:ii::::::::i:::::::::::i:::ii:::::i:i::::::::J::i{::i\:::::;;::=:t:;XP,@~:::::i;:t::j::!i;:i:::::;:(J;i::::;::m;::i::;';ii;:/:;i:::::(Pp~O\:,'i?::::::))i':'i)::
Bromacil 620 1,740 6,800
2,4-Dichloropbenol 560 1,760 2,800
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Table 5 (Continued) .
Exposure Point Concentrations for Chemicals of Greatest Significance
for the Human Health Risk Assessment at OU 2
Antimony
Arsenic
Beryllium
Chromium
Manganese
N'1Cke1
Vanadium .
llfND
15/5
3fND
1l0fND
860/190
140/ND
12O/ND
:::::::;:.;:::;:::;;:,:;::~:,:;;:,:::,::::::::.:.:....,:;,f,~i!I!~I~':III~li!i!i~'~i!: :il'ljl:'j!ii:rl:.~:I,I!I:!:i:!I:::~'!II~I~I!!II!li:::!i~iili'I'III'.:::~il!
20IND 58.4/ND
13/7 532/7.4
7/ND 28/ND
240IND 941/ND
I..5OO/28O 1,780/276
310/ND 1,260/ND
28O/ND 1, 190/ND
aNo chemicals of potential cancero were detected in surface water.
Notes:
95% UCL = 95th percentile of the upper coDfidence limit of the arithmetic mean of the untransformed data set.
RME = Reasonable Maximum Exposure
ppm = parts per million (mgfkg for soil; mgjL for groundwater)
ppb = parts per biDion (,&gfkg for soil; p.gfL for groundwater)
ND = not detected
30540\9403.1D7\TABLE.S
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Table 6
Toxicity Values for Chemicals of Potential Concern
Carcinogenic Effects
ilil.II!III'il'!lililillllllllllli!ilill:'~I!I~llli'li.:IIIIII:i:il!ljlllliI11111111:llil~i!:llilll!li~I'~ :ti::~~:{::::ii:i:~::::i:~::::::'::::::::::~::::::~::::i~::::~i:i:::~:::;i::::~:~:::~;$.!#p#.m~#~~i~~~)~:::~:::::::::::i:i:I:~::I:::i~::;i:::;~:::::::::~::;~:~:::i::~:t:?::::~:~:.;:;
Jt:ii:::::~::;ttget:::t}:;i:t:::i ~:i:ii::::i:~;;~:~t$~~:~I:~ft~::i: :I~~:~:;::i~t:~~~#.o.#[::::m;i@::: :;:::~~::i:~::::;~::~:$~##:::::::~:i::t:
Arsenic 1.75 IRIS 50 HEAST
Beryllium 43 IRIS 8.4 HEAST
Chromium - - 41 HEAST
PCBs 7.7 IRIS - -
Noncarcinogenic Effects
__~-!!_~I
Antimony 0.0004 IRIS - - 1,000 NA Systemic, blood
Skin, keratosis,
hyperp~entauon
No observed effects
NA
No observed effects
Altered immune
function
IRIS
IRIS
-
-
3
100
NA
500
NA
NA
NA
NA
Arsenic
Beryllium
Bromacil
Chromium
0.0003
0.005
0.002"
0.005
-
-
-
-
-
IRIS
-
-
2,4-Dichlorophenol
IRIS
-
-
100
NA
Manganese
0.003
0.14
(food)
0.005
(water)
IRIS
MCPP
Nickel
PCBs
Vanadium
0.001"
0.02
-
Central nervous
system / respiratory
0.00014 IRIS 1 300 system
. Kidney/decreased
- - 3,000 NA weight
- - 300 - Decreased weight
- - - - -
- - 100 NA No observed effects
IRIS
IRIS
-
-
0.007 HEAST
Notes:
8'fbisvalue derived from the RI, where the methodology used to calculate the value is described.
IRIS = lBtegr-ated Risk Information System (EPA database)
HEAST = Health Effects Assessment Summary Tables (EPA)
- = No toxicity information available for this chemical by this pathway
NA = Not available
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Page 36
cancer risk associated with exposure at that intake level. The 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.
Reference doses (R:fI)s) were developed by EP A for evaluating the potential for adverse
health effects associated with exposure to noncarcinogenic chemicals. RIDs are
expressed in units of mgjkg-day and are estimates of acceptable lifetime daily exposure
levels for hum~ including sensitive individuals. Estimated intakes of chemicals of
concern from environmental media (e.g., the amount of a chemical ingested from
contaminated drinking water) are compared with the IUD. RIDs have not been
developed for all noncarcinogens, primarily because of a lack of toxicity data. For
chemicals lacking R:fI)s, surrogate toxicity values were derived from structurally similar
compounds when possible. However, it was not possible to calculate noncancer values
for all chemicals.
Toxicity values are only available for the oral and inhalation pathways. EP A has not
published toxicity values for evaluating the dermal pathway and recommends using the
oral toxicity values to evaluate dermal exposure.
Because of its unique toxicity, lead does not have a verified reference dose. Instead,
EP A 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
multipathway exposures. The results of this model are used to determine whether the
lead present at the site in various media poses 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. Excess
lifetime cancer risks are determined by multiplying the intake level with the cancer
potency factor. These risks are probabilities that are generally expressed in scientific
notation. An excess lifetime cancer risk of 1 x 10-6 indicates that, as a plausible upper
bound, an individual has a one in one million chance of developing cancer as a result of
site-related exposure to a carcinogen over a 70-year lifetime under the specific exposure
conditions at a site. The National Contingency Plan recommends an acceptable target
cancer risk range of 10-6 to 1~ for CERCLA sites.
30S40\9403.107\TEXT
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Potential concern for noncarcinogenic effects of a single contaminant in a single medium
is expressed as the hazard quotient (or the ratio of the estimated intake derived from the
cont.aminant concentration in a single given medium to the contaminant's reference
dose). By adding the HOs for all cont~minants within a medium or across all media to
which a given. population may reasonably be exposed, the hazardindex can be generated.
If the m is less than 1.0, it indicates that noncarcinogenic health effects are unlikely. If
the m is greater than 1.0, it indicates that adverse health effects are possible.
Tables 7 through 10 present noncancer and cancer risk summaries for each area at
au 2. Only under the future residential scenario were carcinogenic and noncarcinogenic
risks found to exceed 1~ or an m of 1, respectively. Risks are presented for
groundwater; however, as discussed previously, these risks are hypothetical because there
are no on-site residential receptors using the groundwater. Risks from exposure to lead
were evaluated using the LEAD 05 biokinetic model recommended by the EP A The
noncancer risks from lead at Area 4 calculated using this model were slightly above
EP A's acceptable limit.
Risks were evaluated for inorganic chemicals in both filtered and unfiltered groundwater
samples from Areas 2/3,4, and 29. The filtering of suspended solids significantly
reduced the risks for the filtered samples. In addition, the contribution of background
levels of metals in soil and groundwater to the overall site risk was evaluated. A large
proportion of the overall risk resulting from inorganics is attributable to naturally
occurring background levels. Although food pathway risks were evaluated in the RI, they
are a source of substantial uncertainty in the overall risk estimates and are not presented
here.
Risk snmm~Ties for Areas 2/3, 4,14, and 29 are presented below.
.
Area 2/3 .
Soil. There were no cancer risks associated with chemicals in soil that exceeded 104.
Antimony and arsenic were found to pose a potential noncancer risk to future residents.
Groundwater. Antimony, arsenic, and manganese were found to produce a noncancer
risk (In = 13). Cancer risk for the groundwater pathway was 4.6 x 104 because of
arsenic in-groundwater. The cancer risk for the filtered groundwater was 1.8 x 1Q4 and
was entirely attributable to arsenic. The noncancer risk from filtered groundwater (HI =
6.4) was due primarily to antimony.
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Table 7
Area 2/3-Summary of RME Noncancer and Cancer Human Health Risks
Ingestion 0.045 B 8. 7E-07 B 1.4 E 2.SE-OS W 0.048 B 2.8E-06 W
Inhalation <0.001 B 1.4&11 B <0.01 B 7.0&10 B <0.001 B 2.4E-I0 B
Dermal 0.004 B 1.0&07 B 0.031 B 7.1&07 B 0.005 B 2.8E-07 B
Combined 0.049 B 9.7E-07 B 1.4 E 2.6E-OS W 0.053 B 3.1&06 W
:t~:::j:::i::j;HH:@trr:::lJjriJ;Ilt:::rtmtjj:Hmjt):::lif::r:j:::::j:II:i:tH:::t:f::t:f}::f::m=:::t::;tttt:t:;::::::::t::rt::::I::::II:):ttrt:i:t:;:r:t:=tt::::H::rrt:rrr::::t:r:::::::::>::...
Ingestion 13. E 4.6&04 E
Inhalation 0.002 B 1.5E-06 W
Dermal 0.028 B 1.5E-06 W
Combined 13. E 4.6&04 E
:@;i4~::!!##:::=Ijj::::rm:j=::::j::I:::::i::::rrlIItIj:::I:q:r==:I:::I:::r:::trt:I:::::{I:tm:m:::::I:::::II=::m:Iif::r:::::::tI=::::tI=j:::m@jII=:tIt::m::n):::::::mrr@:}=:}:):f:::::::::mmI}:\r=:::::H):@:=:j:::;::jj;
Ingestion 0.003 B 7.2E-09 B
Dermal <0.001 B 2. 7E-09 B
Combined 0.004 B 9.9E-09 B
:~1_:::~!::1:~:~::!~' OJ)S3 B 9.8&07 B
14. E
4.9&04 E
0.053 B
3.1&06 w
Notes:
B = Below or at limit of EPA's target noncance1' bazard index (HI ~ 1) or caDce1' risk (ELCR ~ lQ4).
W = Within EPA's target cancer risk range of Itr to lQ4. . .
E = Exceeds EPA's target for noncancer bazard index (HI ~ 1) or cance1' risk (ELCR ~ 1~).
'Tbe groundwater risks presented in this table ale based on unfiltered samples. Tbe cancer risks from filtered groundwater at Area
2/3 (1.8 x 1~) wete due primarily to arscuic; the noncancer risks from filtered groundwater (HI of 6.4) were due primarily to
antimony and manganese. .
.
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Table 8
Area ~SummaIy of RME Noncancer and Cancer Human Health Risks
~
Inption 0.045 B 2.0SOS W 2.1 E 5.4E-04 E 0.074 B 6.0E-OS W
lDhaIabon <0.001 B 3.0&10 B <0.001 B 1.5E-08 B <0.001 B 5.2&09 B
Dermal 0.007 B 2.1B-05 W 0.21 B 1.5E-04 E 0.033 B 5.8&07 B
CombiDed 0.052 B 4.1E-OS w 2.3 E 6.9E-04 E 0.11 B 6.0E-OS w
Ingestion 19. E 3.1&04 E
Inhalation 0.0 B O.OE +00 B
DcmIaJ 0.032 B 5.2&07 B
CombiDed 19. E 3.2E-04 E
mgcsaiOD 0.003 B 6.8&09 B
DcmIaJ <0.001 B 1.1&09 B
CombiDed 0.003 B 7.9~ B
'!f:18:li!'!,!:111 0.055 B 4.1B-05 W 21. E 1.0&03 E 0.11 B 6.0E-OS w
Notes:
B .. BeJow or at limit of EPA's target Doncancer hazard index (HI ~ 1) or cancer risk (ELCR ~ lQ4).
W .. W"1thiD EPA's target = risk r.mge of lQ4 to 1~.
E .. EDzeds EPA's taJget for uoncaacer bazard index (HI ~ 1) or caacer risk (ELCR ~ 1~).
"Ibe groundwater risks praeated in this table are based on uafiltered groundwater samples. The risks from filtered groundwater at
Area 4 (DODcaDcer HI of 1.5, cancer risk of 1.6 x 1~)'_re due primarily to azseDic: and manganese.
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Table 9
Area 14-Summary of RME Noneancer and Cancer Human Health Risks
rtf~mrltW~liiIti]~*~~f'I*tfim~f:I~im~~t~~~~~~~~~jt~~*-~~@~~~~1\1~~ij11f~~~~~~~~fr1;f~ift1M~j~m;}.~~!!t!j~@}}f}~{fr1~r~@
jm.;,tWl;I%.~A:::J(::::jgRtH\g@HW.W1MWMW'-hUf~~JWMffU!@}@l H@fU;::Wlm:~..{::tt:::f::::f@:{::i:
W~~IJ.W tttWti:'::::).itiMfif, Mtt!I#St:W:~% W~;Wi;!~i.mIltt~:: lHS!#¥.#.#g::mRi i:::WW}:~~¥::{tm::W
IDgestioD. <0.001 B 2.2&m B 0.33 B 3.SS(IS W 0.011 B 3.96-06 W
Ift"'D'~~
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Table 10
Area 29-Summary of RME Noncancer and Cancer Human Health Risks
- :tn!!:!:!I:!!!!m~~r~!rp~!!:!:!:tI!fffm! mj;iEj;i:Il~::ImJ!!J:t!!!t!f:1JJfImJ!m!::m~!~J.@:!~mmfW:!::JJ:r:tt:ft:tI:fmj;i:I!:lm::::!::t:~
@tt!{@{lHi~#:::::::~t::i;~:MrMtr:t:f::!:!m: If!ir:flmtmI:rm~~i#.~:lt{:!rr:f!r!}!!:!llrti}!rtl!:!r:::M;~ii#.ip.i@..~({!rrr::rm:!f\m!:
:!@_:;H~m!tt:@tt;Ri.i~ItHi!::: !E~!frr::Mt:tt!~~f;!:!!m:l!!}J!
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Surface Water. There were no cancer or noncancer risks associated with surface water
in excess of the EP A's acceptable risk range or an III of 1.0.
.
Area 4
SoiL Although no single chemical posed a potential noncancer risk, the cumulative
noncancer risk (posed primarily by antimony, arsenic, and MCPP) exceeded a hazard
index of 1 for future residents. The potential cancer risk for future residents- was 6.9 x
10"', resulting solely from PCBs in soil.
Groundwater. Antimony, arsenic, and manganese were found to produce a noncancer
risk to future residents. Arsenic was the only chemical posing a potential cancer risk in
excess of 10"'. The risks for the filtered groundwater were less than for the unfiltered
groundwater and were primarily due to arsenic.
Surface Water. There were no cancer or noncancer risks associated with surface water
in excess of the EP A's acceptable risk range or an III of 1.0.
.
Area 14
SoiL There were no cancer or noncancer risks associated with soil in excess of the
EP A's acceptable risk range or an In of 1.0.
Groundwater. Bromaci1 and 2,4-dichlorophenol in groundwater resulted in a noncancer
risk (In = 42) for future residents. No significant cancer risks were found for the
groundwater. . .
Surface Water. There were no cancer or noncancer risks associated with suJiace water
in excess of the EP A's acceptable risk range or an In of 1.0.
Area 29
.
SoiL There were no cancer or noncancer risks associated with soil in excess of the
EP A's acceptable risk range or an III of 1.0.
3Q54O\9403.107\TEXT
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Groundwater. Antimony, arsenic, chromium, manganese, nickel, and vanadium were
found to produce noncancer risks to future residents (Ill = 15). Arsenic and beryllium
exceeded the target range for carcinogenic effects. The cancer risks for the filtered
groundwater were less than for the unfiltered groundwater and were primarily due to
arsenic.
Surface Water. There were no cancer or noncancer risks associated with surface water
in excess of the EP A's acceptable risk range or an ill of 1.0 associated with surface
water.
7.1.4 Uncertainty
The accuracy of a risk assessment depends to a large extent on the quality and
representativeness of the data and assumptions that are used. The most critical sources
of uncertainty associated with each step of the risk assessment are described below.
.
Exposure Assessment
The exposure assumptions used in the risk assessment are default values recommended
by the EP A These values are not site specific and are intended to be overly
conservative. They are used to ensure that site risks are not underestimated. Because
the groundwater is not currently used, the risks from ingestion of groundwater are
hypothetical.
.
Toxicity Assessment
There are numerous uncertainties associated with the approaches used to develop
toxicity criteria (e.g., differences in study design, species, sex, and route). The magnitude
and direction of uncertainty associated with the toxicity values are' unknown.
As discussed in the toxicity assessment, oral toxicity values have been used for evaluating
dermal exposures. The magnitude and direction of uncenainty associated with this
approach are unknown.
Although chromium was not speciated, the toxicity values used to evaluate chromium are
based onits -carcinogenic form (chromium VI). Using this value will probably result in
an overestimate of risk, because it is unlikely that all the chromium detected on site is in
its carcinogenic form. .
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The cancer slope factor for arsenic is also uncertain, and the EP A has noted that the
actual risks associated with arsenic may be substantially lower than those calculated. In
addition, a verified toxicity factor is not available for bromacil. An alternative toxicity
factor was developed for this risk assessment. This also contributes to the uncertainty
associated with the toxicity criteria. .. .
.
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 nsks may yield a conservative
estimate.
7.2
ECOLOGICAL RISK ASSESSMENT
A screening-level ecological risk assessment was conducted to evaluate potential .
toxicological threats to ecological receptors from contamination at au 2. The evaluation
was performed for both terrestrial and. wetland receptors.
7.2.1 Exposure Assessment
.
Terrestrial Habitat
Areas 2/3,4, 14, and 29 are dominated by a brush and grassland community. Areas 2/3,
4, and 29 are bordered. on at least one side by a mixed evergreen forest community.
Wildlife populations frequenting the sites include microtine (e.g., voles, deer mice),
black-tailed deer, coyote, and birds of prey (e.g., northern harrier, red-tailed.hawk).
Species inhabiting the site are primarily exposed to risks by ingestion ~f:
.
.
.
Chemicals in the soil
Plants that accumulate chemicals from the soil
Prey that accumulate chemicals from ingestion of soil, plants, and other
prey items
30S40\94CX3.107\TEXT
.
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.
Wetland Habitat
Freshwater wetland habitat exists between Areas 2 and 3. Species potentially using the
wetland include hydrophytic plants, plankton, invertebrates, waterfowl, shorebirds,
amphibians, raptors, and mammals. Wildlife in the wetland is primarily exposed to risks
from ingestion of:
.
.
Chemicals in sediment
Chemicals in water
Plants that accumulate chemicals from sediment and water
Prey that accumulate chemicals from sediment, water, plants, and other
prey items
..
.
7:1.:1. Toxicity Assessment
The screening-level assessment of potential ecological risks compared concentrations of
chemicals in sediment with sediment quality values and concentrations of chemicals in
surface water with ambient water quality criteria. Potential exposures of terrestrial
receptors to chemicals detected in the soils were compared with toxicity reference values.
The toxicity reference values were selected to be protective of target organisms following
chronic and continuous exposure to chemicals.
Toxicity reference values for m~mmals and birds were expressed as a dose and were
obtained from a review of available m~mmalian and avian toxicological data. Sediment
toxicity reference values were either obtained from toxicological information compiled by
Ecology or derived from ambient water quality criteria using equilibrium partitioning for
non-ionic organic chemicals. Freshwater toxicity values were derived from either federal
ambient water quality criteria or a review of available aquatic to~city data.
7:1..3 Risk Characterization
.
Terrestrial Habitat
Potential ecological risks from chemicals detected in soil were evaluated using an
exposure modeling approach. The modeling estimated reasonable maximum exposures
to four-receptors with four different foraging patterns: a herbivorous small mammal
(vole), insectivorous small mammal (shrew), carnivorous mammal (coyote), and
carnivorous bird (northern harrier). Results of the ecological risk assessment suggest
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that chemicals in the soil at all areas pose negligible risks to the receptors occupying
higher trophic levels (coyote and northern harrier). However, modeling suggested risks
to organisms at lower trophic levels (vole and shrew) from all areas for the chemicals
listed in Table 11.
Table 11
Chemicals Posing Potential Risks to Terrestrial Organisms at Lower Trophic Levels
. .
Antimony
Cadmium
Lead
. ""."."""""":':":':':':':':':::':":':::.::::::;::::::':::iti!iii:iil)i::;t::ijiiii:::@ t1:iiimi!illiilliiii::::iiij!i&i:Jfii:iii:J::iI::ti!:i:::!:@: i::l:i!::!:!:::i::ii:i:::iii::!:,i::&g!:i:::::i:!::i!::!:::::itf:!::
Antimony 2,3,7,8-TCDD Cadmium
Cadmium Lead
Copper Pentachlorophenol
Lead
Mercury
PCB Aroclor 1260
Pentachlorophenol
Zinc
.
Wetland Habitat
Potential ecological risks posed by chemicals in freshwater sediments were evaluated by
comparing chemical concentrations in area sediments to sediment toxicity reference
values (i.e., Washington state's summary of freshwater sediment criteria or values derived
by using the equilibrium partitioning approach). Sediment toxicity referen~ values are
acceptable to state and federal agencies as indicators of potential ecological impacts.
Arsenic, chromium, copper, iron, lead, manganese, mercury, nickeL zinc, 4,4'-DDT, and
endosulfan sulfate concentrations pose risks to aquatic organisms found in the wetland
between Areas 2 and 3.
Ecological risks posed by chemicals in wetland surface water were evaluated by
comparing the concentrations of chemicals measured in the single sample collected to
surface water toxiCliY -reference values (i.e., federal chronic freshwater ambient water
quality criteria or the lowest freshwater aquatic toxicity value). Chronic ambient water
30540\9403.107\TEXT
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quality criteria are protective of 95 percent of aquatic organisms. Chemicals
representing potential risks to aquatic biota in the Area 2/3 habitat were aluminum,
cyanide, iron, and lead.
7.2.4 Uncertainty
The screening-level ecological risk assessment performed on au 2 was based on
analytical results from soil, freshwater sediment, and surface water samples.
Uncertainties associated with this approach include:
.
.
30S40\9403.107\TEXT
Exposure l\ssessment
.
Exposure models were based on receptor ingestion rates of water, forage,
and soil. Water and forage ingestion rates were not site specific. Soil
ingestion rates were neither site nor species specific.
.
Biotransfer factors were used in the exposure models to estimate chemical
tissue concentrations in prey species. These factors were based on a.
limited number of species and chemicals. Thus, the biotransfer factors may
not appropriately estimate exposure for the receptors used in the models.
.
Risks to terrestrial receptors from chemical exposure were based on
average and reasonable maximum exposure estimates that assume uniform
chemical distribution, and therefore exposure, throughout the site. Based
on past evaluations, chemicals are likely to be heterogeneously distributed
on site; thus, the duration of exposure may be overestimated, thereby
overestimating risk. .
Toxicity Assessment
.
Typically, toxicity reference values were not available for the receptor
species. Therefore, values for species of similar taxonomic classification
were used. The magnitude and direction of uncertainty associated with
extrapolating toxicity vatues betWeen taxonomic groups are unknown.
.e.. - Toxicity reference values were often based on a limited data set. The
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.
Toxicity reference values for surface water assumed that inorganic
chemicals are present in their most biologically available and toxic form.
However, the site-specific characteristics of the chemicals were unknown,
and chemicals are seldom found in the environment in their most toxic
forms. Therefore, potential risks are probably overestimated. - .
7:3
RISK ASSESSl\1ENT CONCLUSIONS
The potential human health risks calculated for OU 2 result primarily from PCBs in soil
at Area 4, bromacil and 2,4-dichlorophenol in groundwater at Area 14, and metals in the
groundwater at Areas 2/3, 4, and 29. The metals responsible for nearly all the potential
human health risks include antimony, arsenic, and manganese. Because these metals are
naturally occurring in the environment, much of the calculated risks may result from
background levels of these metals.
Low ecological risks at the terrestrial portions of OU 2 largely result from metals in soil.
Because analysis did not identify the form of the metals present on site, evaluation was
based on the most toxic form of the chemicals known. It is unlikely the chemicals on
site exist in their most toxic forms; therefore, risks from metals at the terrestrial areas
are likely to be exaggerated. PCB Aroclor 1260 and pentachlorophenol at Area 4 and
2,3,7,8-TCDD at Area 14 are likely to pose the greatest terrestrial ecological risks at
oU 2. .Most of the ecological risks posed to aquatic organisms in the wetland between
Areas 2 and 3 derive from elevated levels of aluminum in the surface water and from
elevated levels of manganese, nicke4 and copper in the sediments.
8.0 REl\1EDIAL ACTION OBJECTIVES (RAOs)
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, welfare, or the envir ..Jnment.
Sampling results and the risk assessment indicate some health risk to hypothetical future
residents from smface soils and groundwater. Remedial action will be conducted at
those areas where there are unacceptable CERCLA human health risks and/or where
chemicals exceed state standards.
30540\94Q3.107\TEXT
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The intent of the remedial action at Areas 2/3, 4, 14, and 29 is to:
.
Reduce risks to hypothetical future residents from groundwater
contaminants at Area 2/3.
.
Reduce the health risk to hypothetical future residents and the .
environmental risk to small ma:tnmals by remediating surface and near-
surface soil (containing PCB, PCP, and MCPP) at Area 4 to meet state and '
federal standards.
.
Reduce risks to hypothetical future residents by removing the sources of
organic cont~mination (the drywell and surrounding soils) at Area 14.
.
Reduce future exposure to Area 29 soil containing residual organic
compounds that exceed state regulatory limits or present ecological risks.
.
Reduce risks to hypothetical future residents from inorganic groundwater
contaminants at Areas 4 and 29 by implementing residential use deed
restrictions and, if necessary, implementing groundwater use restrictions.
.
Minimi7.e the potential for migration of contaminants from surficial soils to
surface water or other media at Areas 4, 14, and 29.
The primary ARARs used in establishing remedial goals and developing alternatives are
discussed below. ARARs are discussed in more detail in Section 122.
3QS4O\94a3.107\TEXT
.
.. The Washington Model Toxies Control Act Oeanup Regulation, Chapter
173-340 WAC, is the applicable regulation used to, set cleanup goals for
soil and groundwater.'
.
The Washington Dangerous Waste Regulation, Chapter 173-303 WAC, is
the applicable regulation for the designation, storage, transportation,
treatment, and disposal of any dangerous waSte generated as a result of
cleanup actions.
.... - -
The Toxic Substances Control Act (TSCA) regulations (40 CFR Part 761)
are applicable when determining disposal requirements for soils containing
-------
AULT FIELD, OPERABLE UNIT 2
U.s. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0054
Fmal Record of Decision
Date: 04/1f:J/94
Page 50
.
The Resource Conservation and Recovery Act (RCRA) regulations (40
CFR Parts 260-268) are the applicable regulations for the designation,
storage, treatment, and disposal of any hazardous waste generated as a
result of cleanup actions.
8.1
SOIL
Specific numeric goals for soil remediation at Areas 4, 14, and 29 are presented in
Table 12. Soils less than 15 feet below the surface (the point of compliance) must be
remediated if the concentration of the cac listed in Table 12 is greater than the
associated cleanup objective. .
.
Area 2/3
Remedial action objectives were not developed for Area 2/3 soils because the soils did
not pose a risk exceeding the CERCLA risk range. Although th~re was a low ecological
risk to wetlands receptors, performing an intrusive remedial action in the wetland would
do more environmental harm than the isolated detections of inorganics warrant.
.
Area 4
Remediation of surface and near-surface soils is required because PCB, PCP, and MCPP
concentrations constitute a human health risk to hypothetical future residents above
~ceptable~wb. .
.
Area 14
While the soil itself at Area 14 does not constitute a current or future unacceptable risk
to human health, the drywell and soil surrounding it are sources of groundwater
. contamination from bromaci1 and 2,4-dichlorophenol (which does represent an
unacceptable risk). Additionally, ecological risks are associated with 2,3,7,8-TCDD
present in surface soils surrounding the drywell. Remedial action is required to
minimize groundwater contamination; source control is one option. Therefore, cleanup
leveb for soil remedial action were developed. .
30540\9403.107\TEXT
-------
I I
AULT FIELD, OPERABLE UNIT 2
U .5. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0054
. Final Record of Decision
Date: 04/26/94
Page 51
Table 12
Remedial Goals Selected for Soils at OU2
. '~.'.'.'.'~.'.'.'.'.'.'.'.....'.'.'.'.'.'.'.'.'.'.'.'.'.""""""""""""""""' . .~1_11~ ............................ ,',',',',",",',',',",',',',',',",',"',',',",',',',',',','.',',',',',',",',',',',',',',',',',',",',',',",',',',',',',',',',',',',',",',,'.'.",',',',
""","...........,"",,"
- ,..,"........,...."......" ~::::I!::.!!:I:!:::i:~I:!11:11'~I::il~I.:i.::I:::.i..::...:!1i:
~:::::::::::::;~::::::::::::::::::;:::::::::::::;:;:::
"""",,,,'"','''''''''''
[[[
,',',','''''.'''.'.'.'.'.'.'.',','.'.'.'.'.'.'.'.'.',..'
.:,;.:-:.:.:.:.:.:.:.:,:.:.:,;.:.:.:.:.;.:.:,;,:.:,;.:.:
""",..'"''''''''''''''''
.:,:.:-:,:.:,:.;.:.:.;.;.:.:.;,:.:.:.;.:.:,:,:.;.;.:,;.:
.........,...,...,..,..,....
.:j!!:II:.!i:~.:II::lilll..:1 1111.'.1111111 r~.g;t .:::~.i~::.::.:::
;;~j~1~j~~~j~~1~j1~~~;:::~:~: ::::: ::::::::::; :~:::;~ :::~:: ::::: :::: :::i:l::!::::::fm~:::iI!t:I!I ::!:i!::::::!!::!::i!:i::It~&:::.::::::::i::~i::.
Area 4 MCPP 80 38.4 MTCA B 1
PCBs 1 0.3 MTCA A 7.7E-6
Pentacblorophenol 8.33 0.8 MTCA B lE-6 0.003
Total Risk/ 8.7E-6 1.003
Effects
Area 14 Bromacil 7.0 1.Q2 MTCA B1 1
2;3,7,8 TCDD 6.67E-6 lE-6 MTCA B lE-6
2,4-Dichlorophcnol 4.8 0.33 MTCA B3 0.02
Total Risk/ lE-6 1.02
Effects
Area 29 Pentachlorophenol 8.33 0.8 MTCA B lE-6
PAHs 1 0.15 MTCA A 7 .3E-6
Total Risk/ 8.3E-6
Effects
Notes:
IBased on National Academy of Science Standards and protection of groundwater.
2E~tnated
3Based on protection of groundwater
MTCA = Model Taxies Control Act, Chapter 173-340 WAC
The remedial goal established for soil at Area 14 is to remediate'soili in the vicinity of
the drywell cont~ining concentrations of bromacil, 2,4-dichlorophenol, and 2,3,7,8-TCDD
above MTCA Method B cleanup levels.
.
}..rea 29
Elevated levels of metals, P AHs, and PCP (one location) were detected in surface soils
at Area...29.. The future residential risk for soil ingestion and contact was within the
-------
AULT FIELD, OPERABLE UNIT 2
U.5. Navy CLEAN Contract
EDgineering Field Activity, Northwest
Contract No. N62474-89-D-9295
CTO 0054
Fmal Record of Decision
Date: 04/2fJ/94
Page 52
(the burn pad and drainage) and numerous samples within this area exceeded MTCA
cleanup levels for P AHs, remedial goals and alternatives were developed for remediation
. of Area 29.
8.2
GROUNDWATER
GroUndwater analysis detected inorganics at Areas 2/3, 4, and 29 at concentrations that
resulted in a human health risk to hypothetical future residents exceeding the risk range.
In addition, vinyl chloride was detected in the perched aquifer at Area 2/3. However,
indications from the sampling program are that the inorganic concentrations may be
caused by excess turbidity in the samples taken. Additional groundwater monitoring is
necessary to establish background concentrations of inorganics based on samples with
low turbidity. Groundwater monitoring is also necessary at Areas 2/3, 4, and 29 to
establish site groundwater concentrations of inorganics based on samples with low
turbidity. In addition, the monitoring program for Area 2/3 will include volatile organic
compounds. At Areas 2/3, 4, and 29, the wells to be sampled would be identical to the
ones used in the OU2/0U3 RI. The results of the groundwater moDitoring will be.
compared to the decision criteria presented in Table 13. If levels exceed the decision
criteria presented in Table 13, EP A, Ecology, and the Navy will evaluate the results and
jointly determine what additional actions may be necessary. These additional actions
may include capping the Area 2/3 landfill.
. .
At Area 14, the risk assessment indicated a future residential noncancer risk from
bromacil and 2,4-dichlorophenol in the groundwater next to the drywell. Therefore,
remedial action is required to reduce this risk to acceptable levels. However, backfill
material around the drywell is the source, not groundwater. Removing the backfill
material is expected to remove any of the risks found in the groundwater. . After the
remedial action, the groundwater will be sampled from a new monitoring well (l4-MW-
1) to confirm soil removal was effective in reducing the groundwater risks. The resultS
of the groundwater monitoring will be compared to the decision criteria presented in
Table 13. If bromacil or 2,4-dichlorophenol concentrations exceed the decision criteria
presented in Table 13, EP A, Ecology, and the Navy will evaluate the results and jointly
determine what additional actions may be necessary. These additional actions may
include further monitoring, excavations, or groundwater treatment.
-------
i I
AULT FIELD, OPERABLE UNIT 2
U.5. Navy CLEAN Contract
Engineeriog Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0054
. Fmal Record of Decision
Date: 04/26/94
Page 53
Table 13
Decision Criteria for Groundwater at OU2
. .
:~;::.:::i:;:;:;::.j:i;:~~~~:t:::::.::.::: ....:.~:~J,0~~l:/0i/...:....I....C"rm:~~;=)()bjective
Antimony 6/background*
Arsenic 0.05/background.
Manganese 8O/background*
Vmyl Chloride O.023jPOL.
Broma~ m
2,4-dichlorophenol 48
Cleanup Level Source
2/3
2/3, 4, 29
2/3, 4, 29.
2/3
14
14
SDWA MCL
MI'CA Method B
MI'CA Method B
MI'CA Method B
NAS Standards
MI'CA Method B
Notes:
*Whichever is higher.
PQL = Practical Quautitation Limit
SDWA = Safe Drinking Water Act
MCL = Maximum Cout!lmin"nt Level
MTCA = Model Toxies Control Act, Chapter 173-340 WAC
NAS = Natioual Academy of Science
8.3
SURFACE WATER
Remedial action is not required for surface water at any of the areas because no risks
exceeding the risk range were identified. While there was a low ecological risk at the
wetland between Area 2 and Area 3, the potential for damage to the wetland from any
remediation is considered greater than the potential benefits of such remediation.
9.0 DESCRIPTION OF ALTERNATIVES
The remedial investigation revealed that surface soils in three of the five areas in au 2
have some contaminant concentrations that require remedial action. Eight alternatives
were evaluated as possible remedial actions. Not all of the alternatives are applicable to
each area. The description of each alternative discusses the area(s) to which it applies.
For example, Alternative 3 (excavation and off-site disposal of contaminated soil) is not
practicable-for Area 2/3 and therefore was not evaluated for that area.
Costs for each alternative are presented in Section 10.7 (see Table 14, page 68).
-------
AULT FIELD, OPERABLE UNIT 2 .
U.s. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0054
Final Record 'of Decision
Date: 04/2fJ/94
Page 54
9.1
ALTERNATIVE 1: NO ACI'ION-AREAS 2/3, 4, 14, AND 29
This alternative is included for comparison purposes as required under CERCLA.
Alternative 1 would not require any action, but does include continued monitoring of the
site every 5 years. This alternative does not sufficiently protect human health and the
environment, nor does it meet state and federal regulations for Areas 2/3, 4, 14, and 29.
It does not remove or remediate potential contam;nants detected in the surface soil or
sediment at OU 2 and, therefore, would result in a continued risk to human health and
the environment.
9.2
ALTERNATIVE 2: INSTITUTIONAL CONTROLS-AREAS 2/3 AND 29
Institutional (physical or anm;n;~trative) controls could prevent or reduce exposure to
chemicals of concern at Areas 2/3 and 29. Such controls alone would not be protective
at Areas 4 and 14 and, therefore, this alternative was not evaluated for those areas.
Institutional controls include warning signs and deed restrictions (to prevent futUre
excavation). This action would also include a 6-mo~th groundwater monitoring program
to establish the background concentrations of inorganics and to confirm that the metals
detected in groundwater were not the result of site activities. A low-stress sampling
method would be employed during the monitoring prograxn, using low-flow pumps. If
the Navy tranSfers the Area 2/3 property to another owner, the deed would contain a
notification that the property contains a past landfill.
This alternative, with the exception of the Area 2/3 deed notification, can commence
within a 15-month' period after the ROD is signed. Remedial activities would take 6
months to complete.
9.3
ALTERNATIVE 3: EXCAVATION, TRANSPORTATION, AND OFF-SITE
DISPOSAL-AREAS 4, 14, AND 29
This alternative involves excavating surface soils from Areas 4 and 29, removing the
drywell and monitoring welll4-MW-l at Area 14 and excavating the associated soils, and
transporting the soilS io a licensed solid waste or RCRA-approved landfill for disposal.
Disposing of soils would require conformance with land disposal restrictions (LDRs).
Dust controls and provisions against the accidental release of the excavated soils back
30S40\94Q3.107\TEXT
-------
I
AULT FIELD, OPERABLE UNIT 2
U.5. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0054
. . Final Record of Decision
Date: 04/26/94
Page 55
into the environment would be implemented during excavation. The excavated areas
would be backfilled with uncontaminated soil and revegetated.
The excavated soils would be characterized to ensure that they are disposed of in a
manner that protects human health and the environment and that complies with state
and federal regulations. According to federal and Washington state definitions (40 CFR
~261.2 and WAC U73-303-016(3)(a», these soils are contaminated media. The state of
Washington requires generators of solid waste to determine whether the was~ is a
dangerous waste or an extremely hazardous waste, using the procedures in WAC ~ 173-
303-070 through 103. These procedures would be followed to characterize the removed
soils to ensure that the proper disposal location or facility would be selected. If required
by the above-listed regulations, the excavated soils would be treated prior to disposal.
At Areas 4 and 29, groundwater monitoring would be performed for 6 months to confirm
that inorganics found in the groundwater are not the result of site activities. At Area 14,
groundwater monitoring would be performed to confirm that organics found in
monitoring well 14- MW -1 are effectively remediated.
The soil removal portion of Alternative 3 applies to each area as follows:
.
Area 2/3
Because chemical detections are scattered (see Figure 9) and discrete areas of surface
soil cont~m;nation were not identified, soil removal was not evaluated for Area 2/3. If
groundwater results indicate that landfilled materials are a ~ource of contamination in
this former landfill, excavation is not considered feasible.
.
Area 4
Surficial soils (approximately 1,750 cubic yards) would be excavated to a depth of
approximately 3 feet (see Figure 10). Confirmatory soil samples would be taken from
evenly spaced areas at the bottom of the excavation. The samples would be analyzed for
PCBs, PCP, and MCPP (~ee Table 12). If sample results exceed the soil cleanup levels
in Table 12, the location where the exceedance occurred would be further excavated and
sampled until cleanup levels were attained.
After backfilling operations were complete, the area would be graded to conform with
surrounding terrain and revegetated.
-------
./~
Flr~ School ~
o -', 0 \~~I
<:) 1 - & II
--_.~~.._~~~~~======----------- 0
..-:,..~ Vr!'i .Ul. [j-----O--~:"'::::::=::;~~---
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, 1 / ;~~ I" I ,'/# ,..,- ~ I. ,--- , .,~.. -.- /
" , ' I ' /_. 1/, " ",i. Sb Area 2 ' .u¥ om. '" ...'
, ".. II' ~ . ..IlL ~' -'!;-..-
" t" ./~. /11 0 I As - landt, 'II I . ~Ii-"-" c.:::
" ""~ '. : ; '-' ~
'I,~. "" I I .. I,:
, ,~"'\\,' '/.... 0 ,,-?I-~;: / --...... ~IL. 4, i Drainage Ditches \.
1'-- /. ,': ',. ,- to Wetland .
/ - - :::~t ~/, '" m~ ... ' :
'f" ...;, ,',j" W .11,. ili.- ! ~
/ ' \" '1 ,'" Pb " ,
/ ", "..."';" " ," Be' ,
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:.------------------:...------~ ...~'~.='............~....-. , '-' I i
II X - - - -"'rh - -'i"- - -'- "- ~ -X"" -'- "- -'- \J :"F~~~9':'X<':'::"- '-::. 'X:.::. :...:..:. '*.:. =.'¥'::':. x:' ~/t.:.::.;.;
I 'j
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..~~~~~:~~ :,~'-:".:~~..
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,
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"
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/
i
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,
,
,
,
,
"
/
:
/
/.'
ED
As
Be
LEGEND
/
./.
"
x
O Sample Location
(Soli Boring)
O Sample Location
(Surface Soli)
~ eoe Detected
W (Soli Boring)
m COC Detected
(Surface Soli)
....... Extent oflnvesllgallon
/
./
+1
NORTH i
o 200
.'-
SCALE IN FEET
CLEAN Figure 9 eTO 0054
OPERABLE UNIT 2
COMPREHENSIVE LONG. Area 2/3 . Spatial Distribution of COCs Detected In Surface Soli NAS WHIDBEY, WA
TERM ENVIRONMENTAL RECORD OF DECISION
-------
)
)
...............~~~...........................~~.........................,
. 0 " .
i!: " D 0 . ~ ". :
, . "0 0 '" .
" ,t." " __----ll_[) 0"0" :
... . " 0 ,..~- --, ' 0 :
-..... ",:i " 9;'''9-115-0--0-----'''' " .." ......Q!
',1, ;1';' i 0' ' .
90 ..'" '-: ", \n /;1';1';1' ! PCB 0 '0\ 0 !
:' ','Ht' rY ! \ , O'
.', '1/ t).-J '00 Sb :
: ',j, DO' 0 \ PCB:
. ~,' O'
! 0 ',~ ' \ \ !
. ' , \ \ .
:. , ~ \:
. '\', .' ,PCB \ \ .
! 0 0 """ 0 \ [] ~CP 0 \ ~ 0 i
: \, q ODD ,\:~
: 0 0 " PCBiB' '------ 0 0 ~ , : t'I'\
. 0' ---- L1' 0- . wPb
: \ " ~. D ---'------' '~,
. ,,:" '. D)J 0 . ,
. ,," ".0 .
: 0 ;' ~,. ,.. "', I W. ,- - - - -[)" - . 0 - :
. 0 ;I' 0" b \\ .' "PC . I ;'0--"'--
: /' a\ \; [MO. P Former Walker: / :
: / /;1' i \\ 0 tJ! if!, : Barn location I / :
: / / '. '\'i '90"'Y I 0 Q v ~~:
. /;1' '... ,.. /'. ''\-- -- -:0 0,' ',I
.. / / , ,'." / , -\!!. I
: I ",I' . """ '~,~.. 85 ' '",I' " ~~ .\
,.t..,~.................:.~......~~'~....::"""....".......~.........~ '.
., -.. ..... ..... --1 I t ~II. ~!- "!,
. - - - I I '- , , Wetland' /
, I ". "
I I '-<
I r
90
85
)
LEGEND
0 Sample Lacallon .
(Soil Boring)
0 Sample Location
(Surface Soli)
ED cae Detected
(Soil Boring)
m COC Detected
(Surface Soil)
. Exceeds Risk Standards
(Soli Boring)
. Exceeds Risk Standards.
(Surface Soil)
11..J Area to be Remediated
....... Extent ollnvestlgatlon
+ 0 100
I I
NORTH SCALE IN FEET
CLEAN Figure 10 CTO 0054
OPERABLE UNIT 2
COMPREHENSIVE LONG. Area 4 . Spatial Distribution 0' COCs Detected In Surface Soli NAS WHIDBEY, WA
TERM ENVIRONMENTAL RECORD OF DECISION
-------
AULT FIELD, OPERABLE UNIT 2
U.s. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
era 0054
FmaI Record of Decision
Date: 04/26/94
Page 58
.
Area 14
1bis alternative (and all of the alternatives developed for Area 14) includes removal of
the drywell and nearby monitoring well (14-MW-1). Prior to their removal, the wells
would be dewatered. To dewater the wells, several well volumes would be pumped from
the drywell and monitoring well; both are expected to recharge slowly. The water would
be pumped into temporary storage tanks and then passed through activated carbon to
remove organics by adsorption to the carbon. The treated water would be disposed of at
a publicly owned treatment works (POTW). The spent carbon would be disposed off
. site. Following dewatering, the well casings would be removed and decontaminated.
Any liquid generated from decontamination would be added to the liquid storage tanks
for treatment. Approximately 1,000 gallons of liquid is expected to be treated.
Following dewatering and concurrent with removal of the well casing, contaminated soil
. surrounding the drywell and well 14-MW-1 would be excavated (see Figure 11). Evenly
spaced confirmatory soil samples would be analyzed for dioxins, 2,4-dichlorophenol, and
bromacil (see Table 12). Excavation and sampling would continue until sampling results
indicated that soil concentrations fell below the cleanup level for 2,4-dichlorophenol and
bromacil. Confirmatory samples for dioxins would be limited to the top 3 feet of soils.
Approximately 420 ~bic yards are expected to be excavated. The depth of the .
excavation would be 15 feet, or 1 foot below the bottom of the drywell casing, whichever
were greater. The excavated soil and well casings would be disposed of off site.
The excavated area would be backfilled with clean soil below approximately 3 feet at the
till/sand interface. The backfill material would be of sufficient impermeability, and
compacted or otherwise made impermeable, to prevent downward migration of
groundwater. After filling operations were complete, the area would be graded to
conform with the surrounding terrain and revegetated.
.
Area 29
Surficial soils (approximately 1,400 cubic yards) would be excavated to a depth of 1.5 to
5 feet (see Figure 12). Evenly spaced confirmatory soil samples would be collected and
analyzed for P AHs and PCP. If chemical concentrations were below the cleanup levels
listed in Table 12 for Area 29, excavation would cease. The excavation would be filled
to original height Willi clean soil, graded to conform with the surrounding terrain, and
revegetated.
~9403.107\TEXT
-------
" f. j
.~.".;/ ;
I !
Building 2555
COCs In Surface Soli
LEGEND
0 SMlple location
IS01BorIng)
0 SMlple localion
ISurlace SOl)
e coe Oeleded
(Soot Boring)
m coe Oeleded
ISu~ace Sootl
Ur'dD Area 10 be Remedaled
....... E.lenlollnvnligaliOn
+ ' r '01
I
NORTH I KAt, Hun
: j:
...' i!
,-~ f j
. .
I;
I'
/ ,!
! i
i j'
.: : .
! !
, I
.. I
: !
.: i
. I
. I
i
j
""""""'''' .
i :',
\' ! ".
j
j
l
'-..-
~ ''''''
,
Building 2555
I
Spring
/II
. ..UO.r".':::~......'.'~. .
. ' . ""'" ..
. N14.18i 14.MW.1 """'''''''' ' . .......'
. tOcJ.DCP! 2800-DCP ...:.............. .. .
:tOU.8romli:1I 8800-8'_11 NI4.11,
.; 0 '
,! tOcJ.DCP :
: I t 8_11'
. ' :
: , @ :
: \ ~i\ 14-MW-3' S
, ~ au-8_IC ~
:' ~~~: @ '. - . . - "''':~'''' ~
: ,..1 25-8,_11 0 'nlermllte~/\""""
, N14.19 t;l, f
' tOu-DCP It"
: :' tau. 8,ollllClI 11!' i :
: / I: :
: i {.8 :
.: . .
,: Site Fence . .
\........................................r.~
R I
, ,.,. ~',
/
COCs In Groundwater
LEGEND
0 NavyWeI
@ Ne""blilCJ1ngWeI
u Compound IS nOl delecled
..... El1enlollnvestigation
+ I r ...
I
NORT" I ItAtf...,(n
CLEAN Figure 11 CTO 0054
OPERABLE UNIT 2
COMPREHENSIVE LONG. Area 14. Spatial Distribution of COCs Detected In Surface Soli and Groundwater NAS WHIDBEV, WA
TERM ENVIRONMENTAL RECORD OF DECISION
-------
j I I
, I I
\ I I
\ I I
/ I I I
/ i I I
"...,' i I I
....' \.,.".. "I I
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... . .. . ............................~.......~..p.......
:r~,.. ", i I I :
: '> ~.' / / I II ~ :
111 :' D~~~ (."PAiA II~ i
I .' ~ liS I
: .: ~ ..', I I :
if ( /"". 0 ~ ~'pb~i
: ".' """ P~fI !
It . I I
: '\.'/ \... :
! ) ~ ,,\ '""'--! CLOVER VALLEY ROAD
*:!f.~ ,Be \;.. . ~L.. -.. -.. -.. _?
.... .;Y; 0 PAH \. if: Drainage Ditch
'::, 11. ,,-''', ,,2,4DNT t,. ........: ~ x '-
\!r '.J ----.----:: PtH m P 'i
! 0<:::::----(--- a: "" 'I':
it -- !\ ......."> PAH /i Q
I.. ,,' / tl '"
II ". ;) sPAFe~~' ,PAH . '\:1 ~
::........~..~.............-r....~'J~...~.... """""'~.'~...~..~.....~;'II'!5
i ; . \ 8
. , " ~
100.,.., Base Golf Course g
"
I
i
I
,
,""""", . .
. \. {"'~".':::":::".........:.'~..
! i \.
\ ; i \ \
J j / Ii
: Tteest
./ f t ....
:' l i ...
./ f: \.
/ !
. ,
"""""""
LEGEND
o Sample locaUon
(Soil Boring)
o Sample locaUon
(Surface Soli)
E9 COC Detected
(Soli Boring)
,m cae Detected
(Surface Soli)
114rSJ Area to be Remedlated
....... Extent ollnvesllgallon
~ 0 100
I
NORTH SCALE IN FEET
-0.
IS'
CLEAN Figure 12 CTa 0054
OPERABLE UNIT 2
COMPREHENSIVE lONG- Area 29 . Spatial Distribution 0' COCs Detected In Surface Soli NAS WHIDBEY. WA
TERM ENVIRONMENTAL RECORD OF DECISION
ACTION NAVY
)
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Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
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Date: 04/26/94
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This alternative can commence within a IS-month period after the ROD is signed. The
remedial action would take approximately 6 months to complete.
9.4
ALTERNATIVE 4: EXCAVATION, TRANSPORTATION, AND ON-BASE
DISPOSAL-AREAS 4, 14, AND 29
Alternative 4 includes the same remedial actions as Alternative 3, with the exception that
the cont::lm;nated soil would be disposed of on base at the Area 6 landfill. This
alternative is applicable to contaminated soils at Areas 4, 14, and 29. Soil excavation,
confirmatory sampling, and backfilling at Areas 4 and 29 would be the same as described
for Alternative 3. Dewatering and removal of the drywell and monitoring well and soil
excavating, sampling, and backfilling at Area 14 would be the same as described for
Alternative 3. The 6-month groundwater monitoring program described in Alternative 3
would be implemented.
The excavated soil would be characterized to ensure disposal in a manner tbat is
protective of human health and the environment and that complies with state and federal
regulations. The Area 6 landfill is u$ned, but will be closed and capped with a
Minimum Functional Standards (MFS)-equivalent cover upon closure. Area 6 is part of
OU 1; the closure of the landfill is described in the OU 1 ROD.
This alternative can commence within a IS-month period after the ROD is signed.
Remedial activities would take approximately 9 months to complete.
9.5
ALTERNATIVE 5: EXCAVATION, TRANSPORTATION, AND OFF-SITE
INCINERATION-AREAS 4, 14, AND 29
This alternative consists of excavating the soils at Areas 4, 14, and 29- and transponing
the soils to a fixed TSCA-approved or RCRA hazardous waste incinerator. Drywell and
monitoring well dewatering and removal at Area 14 and soil excavation and confirmatory
sampling at Areas 4, 14, and 29 would be performed as described for Alternative 3. .
Dust controls and provisions against the accidental release of excavated soils back into
the environment would be implemented during excavation. The excavations would be
backfilled - with clean soils, revegetated, and restored to full use following remediation.
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AULT FIELD, OPERABLE UNIT 2
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Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
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Date: 04/26/94
Page 62
There are no TSCA-approved incinerators in Region 10; the nearest incinerator is in
Utah. Dewatering liquid from the remediation of Area 14 would be treated as described
in Alternative 3, which is considered protective of human health and the environment.
The special backfill requirements described in Alternative 3 for Area 14 would be
implemented. The 6-month groundwater monitoring program described in Alternative 3
would be implemented. .
This alternative can commence within a IS-month period after the ROD is signed.
Remedial activities would take approximately 6 months to complete.
9.6
ALTERNATIVE 6: CAPPING THE AREAS-AREAS 2/3, 4, AND 29
This alternative involves placing a RCRA- or MFS-equivalent cap over the soils at
Areas 2/3, 4, and 29. Capping Area 14 would not remediate the concentrated area of
cont~mina.tion around the drywell; therefore, this alternative was not evaluated for Area
14. .
At Area 2/3, approximately 106,000 square yards (s.y.) of contaminated soils would be
capped; at Area 4, approximately 1,425 s.y. of soils would be capped; and at Area 29,
approximately 2,570 s.y. of soils would be capped. Capping eliminates the potential
exposure pathway for all the areas of OU 2. A RCRA-type cap, which is standard for
capping sites containing hazardous waste, contains two layers serving as barriers to water
infiltration and is topp~d with a minimum 24-inch-thick layer of soil with a 3 to S percent
slope. The top layer would be vegetated to prevent erosion. An MFS-type cap contains
four layers; the third layer is the barrier layer, which is topped with 6 inches of topsoil
for vegetative cover. For both types of soil caps, institutional controls would be
implemented to maintain the integrity of the cover and to prevent future construction in
the capped areas. Long-term groundwater monitoring would be required to' ensure there
is no migration of cont~m;naflts.
This alternative protects human health and the environment and can be commenced
. within a IS-month period after the ROD is signed. Remedial activities would take
approximately 6 months to complete.,
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Engineering Field Activity, Northwest
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Date: 04/'lh/94
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9.7
ALTERNATIVE 7: SOIL COVER-AREA 29
Alternative 7 involv:es placing a 3-foot layer of clean fill over Area 29 and revegetating
the area. Approximately 2,570 square yards of contaminated soils would be covered.
The surface exposure risk would be eliminated by a soil cover and revegetation. Water
infiltration would not be prevented, but P AHs tend to naturally attenuate and not to
. migrate. Institutional controls would be required to prevent future disturbance of these
soils. Groundwater monitoring and limited soil monitoring would .be implemented to .
confirm there is no migration of chemicals.
Soil covers can be implemented to eliminate human health or ecological risks posed by
direct contact with or ingestion of chemicals in surface soils. Because soil covers do not
prevent water infiltration, they were considered only at areas where chemicals in the
surface soil are immobile in the environment and where a soil cover would provide
adequate protectiveness. These two cases exist only at Area 29. Although PCBs at Area
4 are also immobile in the environment, a soil cover was not considered for Area 4
because the magnitude of the risk was greater and more protectiveness was required. In
addition, the Toxic Substances Control Act requires that PCB-contaminated soil be
either incinerated or capped per RCRA
This alternative can commence within a I5-month period after the ROD is signed.
. Remedial activities would take approximately 6 months to complete.
9.8
ALTERNATIVE 8: LANDFARMING-AREA 29
This alternative consists of excavating contaminated soil (approximately 1,400 cubic
yards) at Area 29 and performing on-site bioremediation of the P AHs in soil using
landfanning techniques. Landfanning could be executed at or near the existing location.
The time required to complete remediation of Area 29's surface soils would depend
largely on the outcome of treatability testing and could range from 1 to 2 years. This
alternative would be expected to attain the MTCA Method A cleanup level of 1.0 mgjkg
for total carcinogenic P AHs. The site would be backfilled and revegetated following
excavation.' Groundwater monitoring would be performed for 6 months to confirm that
inorganics found in the groundwater are not the result of site activities.
Landfanning is expected to meet the RAOs, although its ability to do so must be verified
by treatability testing.
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AULT FIELD, OPERABLE UNIT 2
U.s. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-929S
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Date: 04/26/94
Page 64
This alternative can commence within a IS-month period after the ROD is signed.
Remedial activities would take approximately 24 months to complete.
10.0 COMPARATIVE ANALYSIS OF ALTERNATIVES -..
The EP A has established nine criteria for the evaluation of remedial alternatives. The
eight remedial action alternatives discussed in Section 9.0 were evaluated against these
criteria. The following section presents a brief discussion of each remedial alternative
relative to the evaluation criteria to identify a preferred alternative.
10.1
PROTEcrION OF HUMAN REALTII AND nm ENVIRONMENT
The primary risk to human health and the environment is through direct contact with or
ingestion of cODtam;nants. The no-action alternative (Alternative 1) is not considered
protective at any of the areas, because the potential for direct contact with or ingestion
of contam;n;ints would continue to exist. Because Alternative 1 is not .protective, it is
not evaluated further in this ROD. Institutional controls (Alternative 2) are adequately
protective at Areas 2/3 and 29, assuming that results of the groundwater monitoring
program show soil contam;nauts are not being transported into the aquifer. Off-site
disposal, incineration, and capping (Alternatives 3, 5, and 6) are considered protective of
human health and the environment. A cap at Area 2/3 (Alternative 6), while protective
of groundwater, may prove more destructive to the environment overall because of
impacts on the wetland. Alternatives 3 through 8 would be protective of the
environment at Area 29. On-base disposal of soils at Area 6 (Alternative 4) is
considered protective at Areas 4 and 29, because the chemicals of concern, would be
removed and placed in a controlled area. However, Alternative 4 is not considered
protective at Area 14, because bromacil present in Area 14 soils is relatively mobile and
may eventually leach into groundwater if the soils are placed in the Area 6 landfill
(which is unlined). .
10.2
COMPLIANCE wrm ARARs
If the groundwater monitoring program indicates that Area 2/3 is not a source of
inorganic contamination, the institutional controls provided in Alternative 2 would
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Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
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Date: 04/26/94
Page 65
comply with ARARs at Area 2/3. The institutional controls provided in Alternative 2
also satisfy ARARs at Area 29.
Alternatives 3 and 5 comply with all ARARs for Areas 4, 14, and 29. Alternative 4
(disposal at the Area 6 landfill) will satisfy ARARs for Areas 4 and 14, provided that the
excavated soils are not designated dangerous or hazardous waste. - If the excavated soils
are designated as dangerous or hazardous waste, Alternative 4 would not comply witb
the dangerous waste regulations (WAC 173-303) or the RCRA land disposal restrictions
(40 CFR Part 268).
Alternative 6 provides for MFS or RCRA caps over Areas 2/3, 4, and 29; tbe caps would
be designed and constructed to comply with all ARARs. Alternative 7 provides for a soil
cover over Area 29, which meets MARs. Alternative 8 (landfarming) would comply
with all ARARs at Area 29. .
10.3
REDurnON OF TOXICITY, MOBILITY, AND VOLUME THROUGH
TREATMENT
No reduction in toxicity, mobility, or volume through treatment is provided for
cont::.minated soils under Alternatives 1,2, 4, 6, or 7, because treatment is not a
component of these alternatives. Alternative 2 relies on institutional controls for
protectiveness and Alternatives 4, 6, and 7 rely on containment to achieve protectiyeness.
The off-site disposal technology described in Alternative 3 may involve treatment of the .
soils from Areas 4 and 14 using a stabilization process that would reduce the mobility of
the chemicals of concern in soils. Incineration of soils from Areas 4, 14, and 29 under
Alternative 5 would destroy organic compounds to the fullest extent possible.
Landfarming under Alternative 8 would provide for the destruction of the P AH
compounds at Area 29.
Alternatives 3, 4, and 5 each include treatment of Area 14 contaminated drywell and
mouitoring well water with activated carbon as a component of the remedial alternative.
This treatment reduces the mobility and volume of contaminants at Area 14. If the
spent carbon is disposed of in a RCRA landfill, no reduction in the toxicity of the
cont::.mina11ts will occur. If the spent carbon is regenerated, the thermal regeneration
process will permanently destroy the cont::.minants.
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Engineering Field Activity, Northwest
Contract No. N62474-89~D-9295
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Date: 04/26/94
Page 66
10.4
SHORT-TERM EFFECTIVENESS
There are two primary considerations when evaluating alternatives by 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.
Because Alteniative 2 includes no active remediation, no short-term impacts are
expected and remedial goals would be met immediately. Under Alternatives 3 through
8, earthmoving and construction activities would require that protective measures be
taken to ensure worker safety and prevent potential exposure to soil and dust. These
precautions are not expected to be difficult to implement. Alternatives 3, 4, 5, 6, and 8
would impact wildlife in the short term while soil is excavated. Alternative 7 (soil cover
at Area 29) would have less impact on the environment during cover construction.
Several months would be required to complete remedial activities under Alternatives 3
through 7. Landfarming under Alternative 8 would require an extended time
(approximately 2 years) to achieve remedial goals.
10.5
LONG-TERM EFFECTIVENESS AND PERMANENCE
. Institutional controls (Alternative 2) may require periodic maintenance and inspection to
be effective at Areas 2/3 and 29. Both off-site disposal (Alternative 3) and off-site
incineration (Alternative 5) are considered highly effective in the long term, although off-
site incineration is the more permanent remedial action.
Excavation of cont~m;nated soils and their on-base disposal in the Area 6 landfill
(Alternative 4) provide long-term effectiveness and permanence for Area 4 and'Area 29
soils. Long-term controls will be provided at the Area 6 landfill. However, Alternative 4
may not provide long-term effectiveness for Area 14 soils that contain bromacil.
Bromacil is relatively mobile in the environment and may eventually leach into
groundwater if placed in the Area 6 landfill. .
An MFS or RCRA cap (Alternative 6) is considered effective for Area 2/3. The cap
would prevent leaching from the landfill to the groundwater. For Areas 4 and 29, an
MFS or RCRA cap is considered moderately effective, although preventing water
infiltration (a major function of an engineered cap) is not a high priority at these sites.
30540\94a3.107\TEXT
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AULT FIELD, OPERABLE UNIT 2
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0054'
. Final Record of Decision
Date: 04/26/94
Page 67
A soil cover over Area 29 (Alternative 7) is also considered an effective action to
eliminate environmental exposure. Long-term maintenance and monitoring are required
to ensure effectiveness of either the cap or cover. Landfarming Area 29 soils
(Alternative 8) is potentially effective and permanent, but is contingent on successful
treatability testing.
10.6
IMPLEMENT ABILITY
Institutional controls (Alternative 2)'can be easily implemented at Areas 2/3 and 29.
The capping (Alternative 6) and soil cover (Alternative 7) are demonstrated technologies
that are commonly applied, readily implementable, reliable, and present no unusual
construction difficulties. Likewise, the soil excavation and disposal alternatives
(Alternatives 3 and 4) are commonly applied and should present no implementation
difficulties.
Confirmational sampling during soil excavation requires that soil analyses of various
chemicals occur. There should be no difficulty achieving detection limits below the
selected cleanup levels.
Implementation of off-site incineration (Alternative 5) depends upon availability of
incinerators to accept the soils. Landfarming (Alternative 8) would require treatability
testing to verify performance and process parameters prior to implementation.
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
15 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.
10.8
STATE ACCEPTANCE
Ecology concurs with the selection of the final remedial alternative for Areas 2/3, 4, 14,
and 29. Ecology has been involved with ,the development and review of the remedial
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AULT FIELD, OPERABLE UNIT 2
U.S. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
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Final Record of Decision
Date: 04/26/94
Page 68
Table 14
Estimated Costs of Remedial Alternatives
.~Ld ,---
Cap Cost $10,400 $110,000 N/A N/A N/A $2,890,000 N/A NtA
AnnualO&M $16,990 $0 N/A N/A N/A $33,800 N/A N/A
Present Worth $84,000 $110,000 N/A NtA N/A $3,036,000 NtA NtA
Cap Cost $10,400 N/A $1,107,000 $233,000 $6,176,000 $220,000 N/A N/A
AnnualO&M $8,080 N/A $0 $0 $0 $14,500 N/A NtA
Present Worth $45,000 N/A $1,107,000 $233,000 $6,176,000 $283,000 N/A N/A
Cap Cost $10,400 N/A $423,000 $213,000 $1,613,000 N/A N/A N/A
AnnualO&M $8,080 N/A $0 $0 $0 NtA N/A N/A
Present Worth $45,000 N/A $423,000 $213,000 $1,613,000 NtA N/A N/A
C.ap Cust $10,400 $40,000 $918,000 $22S,ooo $4,958,000 $282,700 $210,400 $460,000
Annual O&M $8,080 $0 $0 $0 $0 $2S,7oo $10,400 $0
Present Worth $45,000 $40,000 $918,000 $22S,ooo $4,958,000 $394,000 $255,000 $460,000
Noles:
I Assumes stabilization and disposal of soils in an off-site RCRA landfill.
'Costs assume MI'S cap
N/A = Not applicable
30S40\9403.I07\TABLE.t4
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Engineering Field Activity, Northwest
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investigation, feasibility study, proposed plan, and record of decision. Ecology's
comments have resulted in changes to these documents.
10.9
COMMUNITY ACCEPTANCE
Comments received during the public comment period (November 12 through
December 12, 1993) indicate that the public accepted the proposed plan.
11.0 SELECTED REMEDIES AND CLEANUP LEVELS
This section summarizes the selected remedies for Areas 2/3, 4, 14, and 29 and the
associated cleanup levels, if any.
lLl
THE SELECl'ED REMEDIES
Based on consideration of the CERCLA requirements, the detailed analysis of
alternatives using the nine criteria, and the public comments, the Navy, the EPA, and
Ecology have determined that a combination of Alternatives 2 (institutional controls and
groundwater monitoring), 3 (excavation and off-site disposal), and 4 (excavation and on-
base disposal) is the most appropriate remedy for au 2 at NAS Whidbey Island. The
following outlines the remedies proposed for each area.
ILLI Area 2/3
Institutional controls (residential use deed restrictions) and a 6-rironth groundwater
monitoring program were selected for Area 2/3. The groundwater monitoring program
seeks to confirm that concentrations of inorganics in groundwater are within background
and below risk-based levels. Two rounds of groundwater samples will be collected from
au 2 background wells and site monitoring wells for analysis of total and dissolved
meWs. The sampling will occur once in the wet season and once in the dry season.
Two groundwater sampling rounds will generate sufficient data for statistical analysis and
permit-the-evaluation of any seasonal vanation in the data. Additional action (in the
form of groundwater use restrictions or leachate control) will be considered if test results
show the groundwater poses an unacceptable risk, as defined in Table 13, from inorganic
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EDgioeeriog Field Activity, Northwest
Contract No. N62474-89-D-9295
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Date: 04/26/94
Page 70
chemicals at concentrations above naturally occurring (background) levels. If the
monitoring results confirm that inorganics in groundwater do not exceed decision criteria
in Table 13, then monitoring for inorganics will cease.
The groundwater will also be monitored for volatile organic compounds; thiS will occur
concurrent with the inorganic sampling and yearly until the 5-year review. Depending on
the results of monitoring, the Navy, EPA, and Ecology will determine whether further
monitoring is warranted. -
The estimated costs for this component of the remedy are: capital costs, $110,000;
operation and maintenance (O&M) costs, $0; present worth, $110,000.
lL1.2 Area 4
Alternative 3 is selected as the remedy for Area 4. This involves removal and disposal
of approximately 1,750 cubic yards (to an approximate depth of 3 feet) of PCB-
contaminated soil. The soils from Area 4 will be transported off site to a TSCA-
approved landfill for final disposal. The soils will be tested by the toxic characteristics
leaclring procedure (TCLP) to determine whether stabilization is required prior to
disposal.
The soil removal will meet regulatory soil cleanup standards established under WAC
173-340 (MTCA) for the cae. MTCA cleanup standards for individual chemicals
correspond to a risk-based cancer risk of 1
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U.s. Navy CLEAN Coutract
Eugiueeriug Field Activity, Northwest
Coutract ~o. N62474-89-D-9295
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Date: 04/26/94
Page 71
11.1.3 Area 14
Alternative 3 is the selected remedy for Area 14. This alternative includes pumpout of
the drywell and monitoring well 14- MW -1; treatment of the extracted water
(approximately 1,000 gallons) by carbon adsorption; disposal of the treated water to a
POTW; excavation of the drywell, monitoring well, and approximately 420 cubic yards of
surrounding cont~m;nated soil; and disposal of the soils and decontaminated well casings.
The soils will be transported off site to a licensed solid waste or RCRA-approved
landfill. The soils will be tested for TCLP to determine if solidification is required prior
to disposal.
The remedy will address dioxin-contaminated soil with concentrations in excess of
0.0067 parts per billion (Ppb) and bromacil-contaminated soil with concentrations in
excess of 7.0 ppm, resulting in a residual site lifetime excess cancer risk of 10-6. In
addition, this remedy will ensure the protection of groundwater by addressing soils
containing 2,4-dichlorophenol in excess of 4.8 ppm. After confirmatory sampling
indicates cl~up levels have been met, the excavation will \)e backfilled and revegetated.
Following remediation, monitoring well 14-MW-1 will b~ reinstalled and groundwater
will be sampled in the wet season to confirm that remediation was effective in reducing
bromacil and 2,4-dichlorophenol in the groundwater to- below cleanup levels (70 ppb and
48 ppb, respectively). Welll4-MW-l will be reinstalled downgradient of its original
location, just outside of the excavated/backfilled area. .
The estimated costs for this component of the remedy are: capital costs, $423,000; O&M-
costst $0; present worth, $423,000.. .
11.1.4 Area 29
Alternative 4 is the selected remedy for Area 29. The remedy includes excavation and -
disposal of approximately 1,400 cubic yards of PCP- and PAH-contaminated soil (to a
depth of approximately 3 feet) from several locations surrounding the bum pad. The
excavated soil will be transponed to the NAS Whidbey Island landfill at Area 6 for final
disposal. The disposal will be timed so that the Area 29 soil is placed prior to
installation of an MFS cap at Area 6 (capping of the Area 6 landfill is described in the
ROD fm: -OU 1 at NAS Whidbey Island).
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AULT FIELD, OPERABLE UNIT 2
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Engineering'Field Activity, Northwest
Contract No. N62474-89-D-9295
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Date: 04/26/94
Page 72
The remedy will address PCP- and P AH-cont~minated soils in excess of 833 ppm and
1 ppm, respectively. After confirmatory sampling indicates cleanup levels have been met,
the eXcavation will be backfilled with clean soil and reseeded.
At Area 2.9, low-stress groundwater monitoring will be conducted to determine the level
of inorganics in the groundwater for both on-site and background wells (for similar
reasons as discussed for Area 2/3). Institutional controls may be required if funher
action is warranted. If the concentrations of inorganics in the groundwater exceed those
listed in Table 13, further action, such as institutional controls, is warranted.
The estimated costs for this component of the remedy are: capital costs, $225,000; O&M
costs, $0; present worth, $225,000.
12.0 STATUTORY DETERMINATION
The Navy and the EPA have primary responsibility, under their CERCLA authority, to
ensure that remedial actions will protect human health and the environment. These
goals will be achieved through removal of surface soils, groundwater monitoring, and
implementation of the institutional controls proposed in this ROD. Implementing
institutional controls and establishing a groundwater monitoring program at Area 2/3
will reduce exposure and better define risks associated with groundwater. The removal
,of contaminated surface soils will eHminate on-site exposure patbways caused by these
soils at Areas 4, 14, and 29.
12.1
PROTECI'lON OF HUMAN HEALTH AND THE ENVIRONMENT
The selected remedial actions will protect human health and the environment by
(1) implementing institutional controls in conjunction with groundwater monitoring at
Area 2/3; (2) removing contaminated soils from Areas 4, 14, and 29 and disposing of the
soils in a controlled landfill; and (3) sampling groundwater at Areas 2/3, 4,' and 29 to
confirm that inorganic concentrations are below background and/or risk-based
concentrations.
Implementation of this remedial action will not pose unacceptable shon-term risks to site
workers or nearby residents. There are no critical habitats, floodplains, or historical
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preservation sites within au 2 that required consideration during the RIfFS process. A
bald eagle observed on site was considered in these remedial actions.
12.2
COMPLIANCE WITH APPLICABLE OR RELEVANT AND APPROPRIATE
REQUIREMENTS (ARARs)
The selected remedy for au 2 will comply with federal and state ARARs that have been
identified. The ARARs identified for the site include, but are not limited to, those
discussed in the following sections.
12.2.1 Action-Specific ARARs
The applicable regulations that establish procedures for the designation of waste as
hazardous and standards for the treatment, storage, and shipment of these wastes by
generators are the Hazardous Waste Management Act, 42 U.S.e. Sec 6901 et seq.,
RCRA Subtitle C, 40 CPR Parts 260-268, and the Washington state Dangerous Waste
Regulations, WAC U73-303. .
The state of Washington Hazardous Waste Cleanup:-'Model Toxies Control Act
(Chapter 70.150D RCW) is applicable, because it establishes cleanup standards for
facilities where hazardous substances have come to be located, as codified in WAC
Chapter 173-340, and compliance monitoring requirements.
The National Oil and Hazardous Substances Contingency Plan off-site rule (40 CFR
fi300.440) is applicable to soils removed from Areas 4 and 14 and transponed to an off-
site area for disposal. .
The Toxic Substances Control Act (40 CFR fi761) is applicable to. the disposal of PCB.
contaminated soils removed from Area 4.
The Oean Air Act, Section 101, 42 U.S.e. fi7405 and 7601, and Washington General
Regulations for Air, WAC ~ 173-400, are ~e requirements applicable to SO'lrces of .
fugitive dust generated during the remediation effons; such dust must be controlled to
avoid nuisance conditions. . .
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. Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
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Date: 04/26/94
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The requirements set forth by federal and state Qccupational Safety and Health
Regulations, 29 CFR Part 1926 and WAC ~296-62, Part P, establish applicable health
and safety standards for workers engaged in hazardous waste investigations.
Hazardous Materials Transportation Act regulations (49 CFR Parts 171-172) are
applicable to the transportation of potentially hazardous materials, including samples and
wastes.
12.2.2 Chemical-Specific ARARs
The state of"Washington Hazardous Waste Oeanup-Model Toxies Control Act (RCW
Chapter 70.150D promulgated by WAC 173-340) is applicable for determining cleanup
standards.
The maximum contaminetnt levels and non-zero maximum contaminant level goals'
established under the. Safe Drinking Water Act (40 CFR Parts 141, 142, 143) ~d the
Department of Health drinking water standards (WAC ~246-290-31O) are relevant and
appropriate for determining cleanup levels and evaluating the effectiveness of the
cleanup remedy.
The regulations that establish procedures for the designation of wastes as hazardous or
dangerous (RCRA Subtitle C [40 CFR Part 261] and Washington State Dangerous
Waste Regulations [WAC 173-303]) are applicable when determining handling and
disposal requirements for solid wastes generated during cleanup activities.
12.2.3 Location-Specific ARARs
The Wetland Protection Act (Federal Executive Order 11990,40 CFR Part..6,
Appendix A) is the requirement applicable to the protection of wetlands.
The Rare and Endangered Species Act (16 V.S.e. ~1531, et seq.; 50 CFR Parts 200 and
402) is applicable because a bald eagle was sighted in the area.
12.2.4 Other Criteria, Advisories, or Guidance
Except for the state of Washington Statistical Guidance for Site Managers, there are no
other criteria, advisories, or guidance to be considered for the remedial action.
3QS4O\94C13.107\TEXT
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o
I I
AULT FJELD, OPERABLE UNIT 2
U.s. Navy CLEAN CoDtrad
EugiDeeriDg Field Activity, Northwest
CODtract ~o. N62474-89-D-9295
ero 0054
" Final Record of DecisioD
Date: 04/26/94
Page 75
12.3
COST EFFEcrIVENESS
For Area 2/3, Alternative 2 protects human health and the environment and complies
with ARARs. Alternative 2 will also confirm whether the inorganics in groundwater are
associated with naturally occurring levels and, therefore, do not require remediation.
The cost to implement Alternative 2 at Area 2/3 is less than the cost of capping
. (Alternative 6) and would provide equivalent protection should the results of
groundwater monitoring prove that inorganics in groundwater are within background or
below acceptable limits.
Alternative 3 for Areas 4 and 14 protects human health and the environment and
complies with ARARs. The cost for Alternative 3 ranges from $385,000 to $1,107,000 at
Area 4 and from $250,000 to $423,000 at Area 14, depending on final classification of
the excavated material and the need for stabilization of the waste at the landfill. The
cost for on-site disposal (Alternative 4) is less than for off-site disposal; however, for
Areas 4 and 14 on-site disposal will not meet chemical-specific ARARs if the excavated
materials are designated as a dangerous or hazardous waste. Alternative 6 is also less
costly, but would prevent the Navy's future use of the property and would be less
protective of human health and the environment. Alternative 3, therefore, provides the
best overall protectiveness proportionate to.its cost for Areas 4 and 14.
The remedial action at Area 29 is not required based on CERCLA risk calculations.
However, the Navy has decided to remediate the area to achieve its goal of unrestricted
use. All of the alternatives developed for remediation at Area 29 are protective; the
preferred remedy, Alternative 4 (soil removal and on-base disposal), is the least
expensive.
12.4
UTILIZATION OF PERMANENT SOLUTIONS AND ALTERNATIVE
TREATMENT TECHNOWGIES OR RESOURCE RECOVERY
TECHNOWGIES TO THE MAXIMUM EXTENT PRACTICAL
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 practical, do not negatively impact human health or the environment during
remediation, can be completed in a shon time, and are cost-effective.
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AULT FIELD, OPERABLE UNIT 2
U.s. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
era 0054
Fmal RecOrd of Decision
Date: 04/1b/94
Page 76
The selected remedies meet the statutory requirement to use permanent solutions and
treatment technologies to the maximum extent practical. Treatment of soil from all the
areas was not practical because of the small volumes involved. Combining the soil from
the different areas for treatment was not practical because of the different types of
contaminants at each area. In selecting the remedy, the most important nonthreshold
criteria were cost (incineration was much more expensive than soil excavation and
disposal) and long-term effectiveness (soil excavation and disposal was more protective
than soil cover).
The remedy selected for Area 29 was chosen primarily to comply with MTCA
12.5
PREFERENCE FOR TREATMENT AS PRINCIPAL ELEMENT
Soil from Areas 4 and 14 will be treated prior to disposal if designated a hazardous
waste. Although evaluated, treatment alternatives (incineration and landfarming) were
not selected for soil remediation because of questionable effectiveness (landfarming) and
high cost (incineration).
Water extracted from the drywell and from monitoring welll4-MW-l will be treated
prior to disposal. .
13.0 DOCUMENTATION OF SIGNIFICANT CHANGES
No significant changes to the findings of the RIfFS and the proposed plan have been
made in this ROD.
3QS4O\!M03.107\TEXT
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()
AULT FIELD, OPERABLE UNIT 2
U.s. Navy CLEAN Contract
Engineering Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0054
Attachment A
Date: 04/26/94
Page A-I
ATIACHMENT A
RESPONS~NESSS~Y
OVERVIEW
The responsiveness summary addresses public comments on the proposed plan for
remedial action at NAS Wbidbey Island au 2. The public comment period on the
proposed plan was held from November 12, 1993, to December 12, 1993. A public
meeting was held on December 1, 1993, to explain the proposed plan and solicit public
comments. Members of the public attended the meeting; only one formal comment was
received during the meeting. A transcript of the proceedings of the public meeting is
available in the admini~trative record. No written comments were received on the RI,
FS, or proposed plan during the public comment period.
The one verbal comment received, and the Navy's response to it, is summarized below.
1.
RESPONSE TO COMMENTS ON THE REMEDIAL
INVESTIGATIONjFEASIBILI'IY STUDY REPORTS (RIffS)
No comments were received on the RI or FS reports.
2.
S~Y OF COMMENTS ON THE PROPOSED.PLAN
There was one verbal comment made on the proposed plan. The comment is
snmm~rized below.
Comment
The commenter was concerned that contaminated water runoff could have ponded in the
area south of Dover Valley Road because of clogged drainage ditches.
Response
At the time the fire school was in service, runoff collected in a drainage ditch. The ditch
ran northeast from the bum pad through a culvert to a detention pond on the north side
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AULT FIELD, OPERABLE UNIT 2
U.s. Navy CLEAN Contract
Engineeriug Field Activity, Northwest
Contract No. N62474-89-D-9295
ero 0054
Attachment A
Date: 04/'21)/94
Page A-2
of the service road. (See Figure A-I.) Both the culvert and the detention pond are no
longer present. Aerial photographs taken when the fire school was in operation show
. that there was no consistent drainage from the detention pond. The pond appeared to
be seasonal in nature; it was dry in some of the photographs. The contaminants of
concern (polycyclic aromatic hydrocarbons, or P AHs) in the surface runoff from tbe fire
school site would, therefore, remain in the detention pond and would eventually settle
into the'soil at the bottom of the pond.
At present, there is a wetland south of Oover Valley Road that is the area of concern to
the commenter. This wetland does not appear in past aerial photographs. If the
drainage ditches shown in the photographs had become plugged and flooding had
occurred, the contaminated runoff would have remained on the north side of Clover
Valley Road; there is no defined drainage course and no historical indication of a
wetland on the south side of Oover Valley Road. little or no runoff from the fire
school ponded south of Oover Valley Road in the past.
The present elevations of the culverts under Oover Valley Road and north of the area
of concern indicate that the drainage runs north and collects at the main drainage ditch
north of Oover Valley Road. A drainage ditch along the west side of Golf Course Road
that now collects runoff from the fire school site also ties in to the main drainage at this
point. The topography indicates that the runoff at this collection point then moves
northeasterly, away from the wetland.
P AHs, the contaminaut of concern, tend not to migrate; instead, P AHs remain in the soil
because they bind with organic matter in the soil. This is apparent from the soil and .
surface water samples taken at the site-P AHs were detected only at the location of the
fire school and the detention pond, not in the drainage ditch. Therefore, even if the
runoff from the fire school site had backed up through the culvert and into, the area.
south of Oover Valley Road, it is unlikely that the runoff would have been contaminated
with P AHs.
30S40\94CX3.107\A TTACH.A
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LEGEND
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--- Dirt Road ~ Limits of
--- Investigation
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I
SCALE IN FEET
200
CLEAN Figure A-1 CTOOO54
COMPREHENSIVE LONG- OPERABLE UNIT 2
TERM ENVIRONMENTAL Area 29 Drainage Ditches NAS WhicI)ey, WA
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