PB96-964614
EPA/ROD/R10-96/150
March 1997
EPA Superfund
Record of Decision:
Fort Wainwright, Operable Unit 4,
Fairbanks, North Star Borough, AK
9/24/1996
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RECORD OF DECISION
for
OPERABLE UNIT 4
FORT WAEVWRIGHT
FAIRBANKS, ALASKA
AUGUST 1996
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DECLARATION STATEMENT
for
RECORD OF DECISION
FORT WAINWRIGHT
FAIRBANKS, ALASKA
OPERABLE UNIT 4
AUGUST 1996
SOURCE AREA NAME AND LOCATION
Operable Unit 4
Fort Wainwright
Fairbanks, Alaska
STATEMENT OF BASIS AND PURPOSE
This Record of Decision (ROD) presents the selected remedial actions for Operable Unit 4 (OU-4) at
Fort Wainwright in Fairbanks, Alaska. OU-4 comprises three source areas: the Landfill, the Coal
Storage Yard (CSY), and the Fire Training Pits (FTPs). This ROD was developed in accordance
with the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 as
amended by the Superfund Amendments and Reauthorization Act of 1986; 42 United States Code
Section 9601 et seq.; and, to the extent practicable, the National Oil and Hazardous Substances
Pollution Contingency Plan, 40 Code of Federal Regulations 300 et seq. This decision is based on
the Administrative Record for this Operable Unit.
The United States Army, the United States Environmental Protection Agency, and the State of
Alaska, through the Alaska Department of Environmental Conservation, have agreed to the selected
remedies.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from the Landfill and CSY source areas, if not
addressed by implementing the response actions selected in this ROD, may present substantial
endangerment to public health, welfare, or the environment. Specific groundwater contaminants of
concern at the Landfill include benzene; 1,1,2-trichloroethane; 1,1,2,2-tetrachloroethane; bis(2-
ethylhexyl)phthalate; cis-1,2 dichloroethene; and trichloroethene (TCE). Groundwater contaminants
at the CSY include TCE; bis(2-ethylhexyl)phthalate; toluene; and benzene.
This is the second OU to reach a final-action ROD at this National Priorities List site. This ROD
addresses soil and groundwater contamination at OU-4.
Contamination at the FTPs was limited to localized contaminated petroleum "hot spots" in surface and
shallow subsurface soils. Petroleum contamination, below action levels, was detected in groundwater
at the FTPs. The contaminated soils will be adequately addressed through an Army removal action.
Therefore, no analysis of remedial alternatives was conducted for the FTPs. It is anticipated that this
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will constitute final action for the FTPs.
DESCRIPTION OF THE SELECTED REMEDIES
Selected remedies were chosen from many alternatives as the best method of addressing contaminated
soil and groundwater in OU-4. The selected remedies address the risk by reducing contamination to
below cleanup levels established for OU-4.
The remedial action objectives for the Landfill and CSY will:
• Restore groundwater to drinking water quality;
• Prevent further leaching of contaminants into groundwater;
• Reduce or prevent further migration of contaminated groundwater; and
• Prevent use of groundwater containing contaminants above Safe
Drinking Water Act and State Water Quality Act Standards.
The major components of the remedy at the Landfill yje:
• Capping with engineering controls of the inactive portion of the
Landfill;
• Institutional controls to prevent the use of contaminated groundwater
and restrict site access (via fencing);
• Natural attenuation to attain Alaska Water Quality Standards (AWQS);
and
• A phased approach, implementation of an active groundwater
treatment system (Phase 2), will be considered if capping does not
result in a significant reduction of groundwater contaminants when
evaluated at the five-year review.
The major components of the remedy at the CSY are:
• In situ soil vapor extraction and air sparging of groundwater to
remove solvent contaminants to a level that attains Safe Drinking
Water Act levels;
• Institutional controls to prevent the use of contaminated groundwater
and restrict site access; and
• Natural attenuation to attain AWQS.
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STATUTORY DETERMINATION
The selected remedial actions are protective of human health and the environment, comply with
federal and state requirements that are legally applicable or relevant and appropriate to the remedial
actions, and are cost-effective.
The remedies utilize permanent solutions and alternative treatment technologies to the maximum
extent practicable and satisfy the statutory preference for remedies that employ treatments that reduce
toxicity, mobility, or volume as a principal element.
Because these remedies will result in hazardous substances remaining at these source areas above
health-based levels, a review will be conducted within five years after commencement of remedial
action to ensure that the remedy continues to provide adequate protection of human health and the
environment.
IV
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SIGNATURES
Signature sheet for the foregoing Operable Unit 4, Fort Wainwright, Record of Decision between the
United States Army and United States Environmental Protection Agency, Region X, with concurrence
by the Alaska Department of Environmental Conservation.
William M. Steele ,- j
Lieutenant Geneum, U.S. Army
Commanding —^
Date
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SIGNATURES
Signature sheet for the foregoing Operable Unit 4, Fort Wainwright, Record of Decision between the
United States Army and United States Environmental Protection Agency, Region X, with concurrence
by the Alaska Department of Environmental Conservation.
Chuck Clarke Date
Regional Administrator, Region X
United States Environmental Protection Agency
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SIGNATURES
Signature sheet for the foregoing Operable Unit 4, Fort Wainwright, Record of Decision between the United
States Army and United States Environmental Protection Agency, Region X, with concurrence by the Alaska
Department of Environmental Conservation.
Kurt Fredriksson
Director, Spill Prevention and Response
Alaska Department of Environmental Conservation
Date
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TABLE OF CONTENTS
DECLARATION STATEMENT ii
LIST OF TABLES xiii
LIST OF ILLUSTRATIONS xv
LIST OF ACRONYMS xvi
DECISION SUMMARY 1
1.0 SITE DESCRIPTION 2
1.1 SITE LOCATION AND DESCRIPTION 2
1.1.1 Landfill Source Area 2
1.1.2 Coal Storage Yard Source Area 3
1.1.3 Fire Training Pits 3
1.2 SOILS AND GEOLOGY 3
1.3 HYDROGEOLOGY AND GROUNDWATER USE 4
1.4 LAND USE 5
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES 11
2.1 HISTORY 11
2.1.1 Landfill Source Area 11
2.1.2 Coal Storage Yard Source Area 11
2.1.3 Fire Training Pits Source Area 12
2.2 ENFORCEMENT ACTIVITIES 12
2.3 HIGHLIGHTS OF COMMUNITY PARTICIPATION 12
2.4 SCOPE AND ROLE OF OPERABLE UNIT OR RESPONSE ACTION 13
3.0 SUMMARY OF SOURCE AREA CHARACTERISTICS 14
3.1 LANDFILL SOURCE AREA 14
3.1.1 Physical Features, Hydrogeologic Conditions, and Transport
Pathways 14
3.1.2 Nature and Extent of Contamination 15
3.2 COAL STORAGE YARD SOURCE AREA 16
3.2.1 Physical Features, Hydrogeologic Conditions, and Transport
Pathways 16
3.2.2 Nature and Extent of Contamination 17
4.0 SUMMARY OF SITE RISKS 40
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4.1 IDENTIFICATION OF CHEMICALS OF CONCERN (SCREENING
ANALYSIS) 40
4.2 EXPOSURE ASSESSMENT 41
4.2.1 Identification of Site Uses, Exposed Populations, and Exposure
Pathways 41
4.2.1.1 Source Area Land Use Scenarios 41
4.2.1.2 Exposed Populations and Pathways 41
4.2.1.3 Calculation of Exposure 41
4.3 TOXICITY ASSESSMENT 42
4.4 RISK CHARACTERIZATION 43
4.4.1 Landfill Source Area 44
4.4.2 Coal Storage Yard Source Area 45
4.5 MAJOR UNCERTAINTIES 45
4.6 ECOLOGICAL RISKS 45
4.6.1 Problem Formulation 46
4.6.2 Analysis 47
4.6.3 Risk Characterization 47
4.6.3.1 Risk Estimation 47
4.6.3.2 Risk Description 48
5.0 DESCRIPTION OF ALTERNATIVES 69
5.1 NEED FOR REMEDIAL ACTION 69
5.1.1 Landfill Source Area 69
5.1.2 Coal Storage Yard Source Area 69
5.2 REMEDIAL ACTION OBJECTIVES 70
5.2.1 Landfill Source Area 70
5.2.1.1 Groundwater 70
5.2.2 Coal Storage Yard Source Area 70
5.2.2.1 Groundwater 70
5.2.2.2 Soil 71
5.3 GOALS OF REMEDIAL ACTION 71
5.4 SIGNIFICANT APPLICABLE OR RELEVANT AND APPROPRIATE
REQUIREMENTS 71
5.5 DESCRIPTION OF ALTERNATIVES 72
5.5.1 Landfill Source Area 72
5.5.1.1 Alternative 1: No Action 72
5.5.1.2 Alternative 2: Institutional Controls,
Natural Attenuation, and Groundwater
Monitoring/Evaluation 72
5.5.1.3 Alternatives: A phased approach involving
capping of the soils in the older, inactive
portion of the Landfill, natural attenuation
of groundwater; groundwater monitoring/
evaluation; and institutional controls.
Phase 2, if necessary, would involve
evaluation and implementation of an active
groundwater treatment system 74
5.5.1.4 Alternative 4: On-Site Treatment of
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Table of Contents (Cont.)
Groundwater Via Extraction and Treatment (Air
Stripping with Liquid-Phase Carbon Adsorption
of Ultraviolet Oxidation), Groundwater
Monitoring/Evaluation, and Institutional
Controls 75
5.5.1.5 Alternatives: Capping of the Older,
Inactive Portion of the Landfill, On-Site
Treatment of Groundwater Via Extraction and
Treatment (Air Stripping with Liquid-Phase
Carbon Adsorption or Ultraviolet Oxidation),
Groundwater Monitoring/Evaluation, and
Institutional Controls 76
5.5.2 Coal Storage Yard Source Area 76
5.5.2.1 Alternative 1: No Action 76
5.5.2.2 Alternative 2: Institutional Controls,
Natural Attenuation, and Groundwater
Monitoring/Evaluation 77
5.5.2.3 Alternative 3: Excavation and Off-Site Treatment of Soils
Via Low-Temperature Thermal Desorption, Natural
Attenuation, Groundwater Monitoring/Evaluation, and
Institutional Controls 78
5.5.2.4 Alternative 4: Excavation and Off-Site Treatment of Soils
Via Low-Temperature Thermal Desorption, On-Site
Treatment of Groundwater Via Extraction and Treatment
(Air Stripping with Liquid-Phase Carbon Adsorption or
Ultraviolet Oxidation), Groundwater
Monitoring/Evaluation, and Institutional
Controls 78
5.5.2.5 Alternative 5: In Situ Treatment of Soils Via Vacuum
Extraction System Enhanced by Steam Injection or
Bioventing, Natural Attenuation, Groundwater
Monitoring/Evaluation, and Institutional Controls 79
5.5.2.6 Alternative 6: In Situ Treatment of Soils Via Vacuum
Extraction Enhanced by Steam Injection or Bioventing, In
Situ Treatment of Groundwater Via Air Sparging,
Groundwater Monitoring/Evaluation, and Institutional
Controls 80
6.0 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES 87
6.1 LANDFILL SOURCE AREA (COMPARATIVE ANALYSIS OF
ALTERNATIVES) 87
6.1.1 Threshold Criteria 87
6.1.1.1 Overall Protection of Human Health and the Environment 87
6.1.1.2 Compliance with Applicable or Relevant and Appropriate
Requirements 87
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Table of Contents (Cont.)
6.1.2 Primary Balancing Criteria 87
6.1.2.1 Long-Term Effectiveness and Permanence 87
6.1.2.2 Reduction of Toxicity, Mobility, and Volume Through
Treatment 88
6.1.2.3 Short-Term Effectiveness 88
6.1.2.4 Implementability 88
6.1.2.5 Cost 88
6.1.3 Modifying Criteria 89
6.1.3.1 State Acceptance 89
6.1.3.2 Community Acceptance 89
6.2 COAL STORAGE YARD SOURCE AREA (COMPARATIVE ANALYSIS OF
ALTERNATIVES) 89
6.2.1 Threshold Criteria 89
6.2.1.1 Overall Protection of Human Health and the Environment 89
6.2.1.2 Compliance with Applicable or Relevant and Appropriate
Requirements 89
6.2.2 Balancing Criteria 89
6.2.2.1 Long-Term Effectiveness and Permanence 89
6.2.2.2 Reduction of Toxicity, Mobility, and Volume Through
Treatment 90
6.2.2.3 Short-Term Effectiveness 90
6.2.2.4 Implementability 90
6.2.2.5 Costs 91
6.2.3 Modifying Criteria 91
6.2.3.1 State Acceptance 91
6.2.3.2 Community Acceptance 91
7.0 SELECTED REMEDIES 94
7.1 LANDFILL SOURCE AREA 94
7.1.1 Major Components of the Selected Remedy 94
7.2 COAL STORAGE YARD SOURCE AREA 95
7.2.1 Major Components of the Selected Remedy 95
8.0 STATUTORY DETERMINATIONS 100
8.1 PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT 100
8.1.1 Landfill Source Area 100
8.1.2 Coal Storage Yard Source Area 100
8.2 COMPLIANCE WITH APPLICABLE OR RELEVANT AND APPROPRIATE
REQUIREMENTS AND TO-BE-CONSIDERED GUIDANCE 100
8.2.1 Applicable or Relevant and Appropriate Description 100
8.2.2 Chemical-Specific Applicable or Relevant and Appropriate
Requirement 101
8.2.3 Location-Specific Applicable or Relevant and Appropriate
Requirement 102
8.2.4 Action-Specific Applicable or Relevant and Appropriate
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Table of Contents (Cont.)
Requirement 102
8.2.5 Information To-Be-Considered 102
8.3 COST EFFECTIVENESS 102
8.4 UTILIZATION OF PERMANENT SOLUTIONS AND ALTERNATIVE
TREATMENT TECHNOLOGIES OR RESOURCE RECOVERY
TECHNOLOGIES TO THE MAXIMUM EXTENT PRACTICABLE 103
8.5 PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT 103
9.0 DOCUMENTATION OF SIGNIFICANT CHANGES 104
Appendix
A ARMY DECISION DOCUMENT FOR THE FIRE TRAINING PITS 105
B RESPONSIVENESS SUMMARY Ill
C COST CALCULATIONS, LANDFILL AND COAL STORAGE YARD
SOURCE AREAS 115
XII
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LIST OF TABLES
Table Page
3-1 Summary of 1993 Groundwater Results, Landfill Source Area 19
3-2 Volatile Organic Compounds of Concern, Results from 1990 to 1994,
AP-5588 and AP-5589 23
3-3 1993 FSVOC Results, Coal Storage Yard Source Area 25
3-4 1993 Microwell Analytical Results, Coal Storage Yard Source Area 27
3-5 Summary of 1993 Groundwater Results, Coal Storage Yard Source Area 28
3-6 Summary of 1994 Groundwater Results, Coal Storage Yard Source Area 34
4-1 Chemicals of Concern from Human Health Risk Assessment 51
4-2 Potential Exposure Routes, Landfill Source Area, from Human Health Risk
Assessment 52
4-3 Potential Exposure Routes, Coal Storage Yard Storage Area, from Human
Health Risk Assessment 53
4-4 Exposure Point Concentrations for Soils, Current and Future Exposure
Scenarios, from Human Health Risk Assessment 54
4-5 Exposure Point Concentrations in Groundwater (/xg/L) from Human Health
Risk Assessment 59
4-6 Potential RME Risks: On-Site Groundwater, from Human Health Risk
Assessment 64
5-1 Chemical-Specific Cleanup Goals for Groundwater, Landfill Source Area 82
XIII
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List of Tables (Cont.)
5-2 Chemical-Specific Cleanup Goals for Groundwater, Coal Storage Yard Source Area .... 84
6-1 Present-Worth Costs for Remedial Alternatives, Landfill Source Area 92
6-2 Present-Worth Costs for Remedial Alternatives, Coal Storage Yard Source Area 93
7-1 Chemical-Specific Cleanup Goals for Groundwater, Landfill Source Area 97
7-2 Chemical-Specific Cleanup Goals for Groundwater and Soil, Coal Storage Yard
Source Area 98
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LIST OF ILLUSTRATIONS
Figure Page
1-1 Source Area Location Map 6
1-2 Landfill Source Area Location Map 7
1-3 Coal Storage Yard Source Area Location Map 8
1-4 Fire Training Pits Area Source Area Location Map 9
1-5 Water Supply Well Map 10
3-1 Landfill Source Area, Contaminants of Concern in Groundwater 37
3-2 Coal Storage Yard Source Area, Contaminants of Concern in Soil 38
3-3 Coal Storage Yard Source Area, Contaminants of Concern in Groundwater 39
4-1 Total Excess Lifetime Cancer Risks Associated with Groundwater at the
Landfill Source Area (RME Assumptions) 65
4-2 Total Excess Lifetime Cancer Risks Associated with Groundwater at the
Coal Storage Yard Area (RME Assumptions) 66
4-3 Total Hazard Indices Associated with Groundwater at the Landfill Source
Area (RME Assumptions) 67
4-4 Total Hazard Indices Associated with Groundwater at the Coal Storage
Yard Source Area (RME Assumptions) 68
5-1 Soil Areas Requiring Remediation in Coal Storage Yard Source Area
Location Map 86
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LIST OF ACRONYMS
AAC Alaska Administrative Code
ADEC Alaska Department of Environmental Conservation
ARARs Applicable or Relevant and Appropriate Requirements
Army United States Army
AS Air Sparging
AWQS Alaska Water Quality Standards
BGS Below Ground Surface
BTEX Benzene, Toluene, Ethylbenzene, and Total Xylenes
C Celsius
CERCLA Comprehensive Environmental Response, Compensation, and Liability Act
CFR Code of Federal Regulations
cm/sec Centimeters Per Second
CSV Coal Storage Yard
EPA United States Environmental Protection Agency
feet/day Feet Per Day
FFA Federal Facilities Agreement
foot/foot Foot Per Foot
FS Feasibility Study
ft/year Feet Per Year
FTPs Fire Training Pits
gallons/day Gallons Per Day
gpm Gallons Per Minute
LTTD Low-Temperature Thermal Desorption
MCLs Maximum Contaminant Levels
/ig/L Micrograms Per Liter
MUS Municipal Utility System
NCP National Contingency Plan
NPDES National Pollution Discharge Elimination System
NPL National Priorities List
O&M Operation and Maintenance
OU-4 Operable Unit 4
PCA 1,1,2,2-Tetrachloroethane
POLs Petroleum, Oil, and Lubricants
PPE Personal Protective Equipment
RAOs Remedial Action Objectives
RBCs Risk-Based Concentrations
RCRA Resource Conservation and Recovery Act
RI Remedial Investigation
xvi
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List of Acronyms (Cont.)
ROD Record of Decision
SARA Superfund Amendments and Reauthorization Act of 1986
TBC To-Be-Considered
TCE Trichloroethene
TRPH Total Recoverable Petroleum Hydrocarbons
USTs Underground Storage Tanks
UV Ultraviolet
VES Vacuum Extraction System
VOC Volatile Organic Compound
xvi i
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DECISION SUMMARY
RECORD OF DECISION
for
OPERABLE UNIT 4
FORT WAINWRIGHT
FAIRBANKS, ALASKA
AUGUST 1996
This decision summary provides an overview of the problems posed by the contaminants at Fort
Wainwright, Operable Unit 4 (OU-4). This summary describes the physical features of the site, the
contaminants present, and the associated risks to human health and the environment. The summary
also describes the remedial alternatives considered, provides the rationale for the remedial actions
selected, and states how the remedial actions satisfy the Comprehensive Environmental Response,
Compensation, and Liability Act of 1980 (CERCLA) statutory requirements.
The Army completed a Remedial Investigation (RI) to provide information on the nature and extent of
contamination of soil and groundwater. A Baseline Risk Assessment was developed and used in
conjunction with the RI to determine the need for remedial action and to aid in the selection of
remedies. A Feasibility Study (FS) was completed to evaluate remedial options.
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1.0 SITE DESCRIPTION
1.1 SITE LOCATION AND DESCRIPTION
Fort Wainwright, also referred to as the "site," occupies 918,000 acres on the east side of Fairbanks,
Alaska. Fort Wainwright originally was established in 1938 as a cold-weather testing station. During
World War II, it served as a crew-transfer point in the Army Air Corps' lend-lease program. After
the war, it became a resupply and maintenance base for the remote Distant Early Warning sites and
experimental station in the Arctic Ocean. In 1961, all operations were transferred to the United
States Army.
Current, primary missions at Fort Wainwright include training of infantry soldiers in the arctic
environment, testing of equipment in arctic conditions, preparation of troops for defense of the Pacific
Rim, and rapid deployment of troops worldwide. On-site industrial activities include use of fixed-
wing aircraft, helicopters, vehicle maintenance, and support activities. Fort Wainwright includes the
main post area, a range complex, and two maneuver areas.
OU-4 consists of three source areas which include the Landfill, Coal Storage Yard (CSV), and the
Fire Training Pits (FTPs). The Landfill is located on the north side of the Chena River, while the
CSV and the FTPs are located on the south side of the River. The Chena River flows through Fort
Wainwright and the City of Fairbanks into the Tanana River. Figure 1-1 illustrates the entire
installation and each source area's location.
1.1.1 Landfill Source Area
A detailed map of the Landfill source area is depicted on Figure 1-2. The Landfill source area is
located at the base of Birch Hill. It includes 60 acres, approximately 40 acres north of River Road
and a 20-acre area immediately south of River Road (the former trench area as shown on Figure 1-2).
The older southwest portion of the Landfill and the former trench area are inactive; the remaining
portion is active. Landfill activities began in the early 1950s. Based on historical aerial photographs,
waste was initially dumped into gravel pits, burned, and covered. During the late 1950s, the Landfill
began receiving most wastes generated at the Post. In the early 1960s, trenching and burning ceased
and wastes were spread, compacted by bulldozer, and covered with coal ash generated from the Fort
Wainwright power plant.
The Landfill serves Fort Wainwright only. The City of Fairbanks uses a separate landfill facility.
Current refuse disposal activities are restricted to the cleared area north of River Road in accordance
with State of Alaska Permit No. 9131-BA007. Refuse is added in "lifts" or compacted layers with a
cover application of coal ash or soil and averages approximately 50 feet above the surrounding grade.
Wetlands border the Landfill to the north and east, and black spruce forest borders the remainder of
the source area, except in areas cleared for access to the Landfill along River Road. The former
trench area south of River Road is covered by an approximately 20-year-old mixed, hardwood/spruce
forest. Gravel quarry pits border the former trench area on the west side. The trench area was used
as a disposal area for wet garbage. The source area is in a 500-year floodplain. No endangered or
threatened species reside in the area. No known historic sites are in the source area.
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1.1.2 Coal Storage Yard Source Area
The CSV is south of Fort Wainwright's coal-fired cogeneration power plant as shown on Figure 1-3.
This power plant is the sole source of heat and electricity for Fort Wainwright. Coal is stored in the
yard directly on the ground. From the 1960s to 1993, the active coal pile was sprayed with waste
petroleum fuel products, such as diesel; fuel oil; solvents; and lubricants from tanks, railroad cars,
and drums, to increase the British thermal unit content of the coal and output of the plant. This
practice has been discontinued.
Contaminated areas resulting from historical practices conducted at the CSY source area include soil
under the active coal pile and a fenced storage area adjacent to the active coal pile. Within the fenced
storage area, two underground storage tanks (USTs) used to store waste products were removed in the
summer of 1995. A third tank used to store diesel for power plant equipment is located in this area.
It was upgraded in 1991 and is still in use.
The areas north and east of the CSY are industrial areas, while the areas to the south and west have
mixed hardwood forests. The cooling pond is a man-made pond used solely for industrial purposes to
cool circulated water from the power plant. The source area is in a 500-year floodplain. No
endangered or threatened species reside in the area. No known historic sites are in the source area.
1.1.3 Fire Training Pits
The FTPs source area consists of two FTPs (FTP 3A and FTP 3B) and a depression area located
northwest of FTP 3B. FTP 3A consists of a large, square, grassy area surrounded by trees and is
accessed through a gate at the northeast corner, as shown on Figure 1-4. Miscellaneous debris and
tanks were stored within the area including a row of charred cars, trucks, and aircraft; an
aboveground water tank; and empty USTs. These debris were removed in spring 1995. FTP 3B
consists of a 7.5-acre area that is approximately 1 to 3 feet lower than the surrounding forest. Each
of the cleared FTP areas is surrounded by thickly wooded areas and is accessed by dirt roads
throughout the area. The depression area is the smallest portion of the FTP area and contains two
circular areas of stained soil. This depression area is 2 feet lower than the surrounding area and is
vegetated with grass and saplings.
The FTPs were used to conduct fire training exercises. During these exercises, waste petroleum fuel
products such as diesel, jet petroleum, oil, solvents, transmission fluid, hydraulic fluid, and brake
fluid were burned. The exercises involved saturating the soil in each unlined training pit with water,
discharging fuel into the pit, igniting the fuel, then extinguishing the fire. The source area is in a
500-year floodplain. No endangered or threatened species reside in the area. No known historic sites
are in the source area.
1.2 SOILS AND GEOLOGY
Fort Wainwright is underlain by soil and unconsolidated sediment that consists of silt, sand, and
gravel and ranges in thickness from 10 feet to more than 400 feet before encountering bedrock. In
the OU-4 source areas, soil types are more coarse-grained and include higher percentages of sand and
gravel. Discontinuous permafrost is found at depths ranging from 3 feet to 50 feet or more
throughout Fort Wainwright but is more prevalent on the north side of the Chena River.
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1.3 HYDROGEOLOGY AND GROUNDWATER USE
The main aquifer in the Fort Wainwright area is the Tanana Basin alluvial aquifer in a buried river
valley. This aquifer ranges from a few feet thick at the base of Birch Hill to at least 300 feet thick
under the fort's main cantonment area. The aquifer may reach a thickness of 700 feet in the Tanana
River valley. Groundwater in the Tanana-Chena floodplain generally is considered to be unconfined
in permafrost-free areas. A confined aquifer may develop seasonally where the depth to the water
table is less than the depth of the seasonal frost penetration.
Groundwater movement between the Tanana and Chena Rivers generally follows a northwest regional
direction, similar to the flow direction of the rivers. The Chena River flows through Fort
Wainwright and the City of Fairbanks into the Tanana River. The Tanana River borders the southern
portion of Fort Wainwright. Flow does fluctuate seasonally because of the effects of changing river
stages in the Tanana River and, to a lesser extent, in the Chena River. Groundwater levels near the
Chena River fluctuate greatly because of river stage and interactions with the Tanana River.
Typically, groundwater levels rise when the river stage increases, particularly during spring breakup
and the late summer runoff. Groundwater levels usually drop during fall and winter, when
precipitation becomes snow. During winter, groundwater seeps into surface water bodies, such as the
Chena River, and produces overflow ice. In addition to shifts in the groundwater flow direction due
to the surface water hydrology, the groundwater flow direction may be impacted by high-volume
pumping associated with gravel pit dewatering activities.
The depth to groundwater varies and may range between 5 to 15 feet at the OU-4 source areas.
Within the upper portion of the aquifer, the predominant groundwater flow direction is toward the
Chena River. Groundwater in the deeper portion of the aquifer zone beneath the Landfill generally
flows to the west-northwest and is partially confined by discontinuous permafrost.
Where present, permafrost forms discontinuous confining layers that influence groundwater movement
and distribution. The presence of near-surface permafrost usually retards groundwater movement
within the shallow subsurface. Three types of aquifers are associated with permafrost:
suprapermafrost aquifers, intrapermafrost aquifers, and subpermafrost aquifers.
• A suprapermafrost aquifer is located above a permafrost layer where
the permafrost acts as a relatively impermeable boundary.
Suprapermafrost aquifers are usually seasonal aquifers that freeze or
experience significant storage depletion in the winter. Many of the
monitoring wells at Fort Wainwright and some domestic wells are
completed in the suprapermafrost aquifer;
• Intrapermafrost aquifers are found in unfrozen zones (talik) within the
body of permafrost; and
• Subpermafrost aquifers are located below the base of the permafrost.
Groundwater is the only source of potable water used at Fort Wainwright and the Fairbanks area.
The Post potable water supply comes from two large-capacity wells located 900 feet hydrologically
downgradient of the CSV (see Figure 1-5). The Post water supply wells are completed at depths
averaging approximately 120 feet and pump at a rate of 1.5 to 2.5 million gallons per day
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(gallons/day) into a water treatment plant. Six standby supply wells are also located 900 feet
hydrogeologically downgradient of the CSY. These wells, if used in an emergency, will supply
unfiltered water to the main drinking water supply system for Fort Wainwright.
The City of Fairbanks uses this same aquifer and has four Municipal Utility System (MUS) wells
located 1 mile downgradient of the Post's boundaries, on the banks of the Chena River. These wells
serve as the main supply for the majority of the population of the City of Fairbanks. Four MUS
wells are completed at depths approximately 90 feet below ground surface (BGS) and pump at a rate
of 5 million gallons/day.
1.4 LAND USE
Current land use for the OU-4 source areas is light industrial. Domestic water use does not occur at
the OU-4 source areas; however, groundwater in the aquifer underneath the OU-4 source areas is the
sole source of drinking water for both Fort Wainwright and the City of Fairbanks. Access to the
inactive portion of the Landfill north of River Road is currently restricted. The CSY source area also
is located in a restricted area. The FTPs source area is not developed and is used for military
exercises and recreation.
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CORPS OF ENGINEERS
U.S. 7\RMY
POTENTIAL/RE-LXDCATIONOF
HUMAN WASTE Pl
CURRENT HUMAN WASTE PIT
LEGEND
__ TRAIL
f==^ ROAD
---- DRAINAGE
•*• WETUND
CONTOUR INTERVAL
(FEET)
FENCE
FORT WAINWRIGHT KEY PLAN
SCALE IN FEET
750 1500
2250
ecology and environment, inc.
International Spacbllats hi tha Emrircnment
U.S. ARMY
ENGINEER DISTRICT, ALASKA
CORPS OF ENGINEERS
ANCHORAGE, ALASKA
Figure 1-2
LANDFILL SOURCE AREA
LOCATION MAP
OPERABLE UNIT 4
FAIRBANKS
ALASKA
JOB. NO.
JY3000
FILE NO.
JT21-2A
DATE:
05-17-96
PLATE
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CORPS 01- LNGINEERS
U.S. ARMY
AMMO
STORAGE
DEPRESSION AREA
FORT WAINWRIGHT KEY PLAN
FIRE TRAINING
PIT 3A
0 250 500 1,000 1,500 2,000
U.S. ARMY
ENGINEER DISTRICT, ALASKA
CORPS OF ENGINEERS
ANCHORAGE, ALASKA
ecology and environment, inc.
International Specialists in the Environment
Figure 1-4
FIRE TRAINING PITS AREA SOURCE AREA
LOCATION MAP
OPERABLE UNIT 4
JOB. NO.
LABOR-JT2901
COMP-JT2950
FILE NO.
JT21-4A.DWG
DATE:
05-15-96
-------
U.S. ARMY
ENGINEER DISTRICT. ALASKA
CORPS OF ENGINEERS
ANCHORAGE, ALASKA
ecology and environment, inc.
WATER SUPPLY WELL
CONTOURS
Figure 1-5
WATER SUPPLY WELL
MAP
OPERABLE UNIT 4
FAIRBANKS
DATE:
05-15-96
JOB. NO.
JT2000
LOCATION MAP
10
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2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES
2.1 SITE HISTORY
The source areas associated with OU-4 have limited documents available describing past practices, but
each source area has undergone prior sampling investigations. The Landfill and FTPs source areas
were listed in the Resource Conservation and Recovery Act (RCRA) Facility Assessment as hazardous
waste sites that required further evaluation in order to obtain Fort Wainwright's RCRA Part B Permit.
2.1.1 Landfill Source Area
The Landfill was one of two source areas initially used to rank Fort Wainwright on the National
Priorities List (NPL), based on samples identifying groundwater contamination in 1986. Wastes that
may have been disposed of at the Landfill during the 1950s include human waste; household refuse;
waste petroleum, oil, and lubricants (POLs); hazardous waste; solvents; pesticides; asbestos;
construction debris; and inert munitions. Historically, the quantity and type of waste disposed at the
Landfill were not documented.
Previous investigations identified waste practices and some wastes known or suspected to have been
disposed of at the Landfill. A 1983 United States Army Environmental Hygiene Agency study
estimated that at that time, 7.7 tons of solid waste were generated per day or approximately 8,000
cubic yards per year. The report stated that the practice of the day was to dispose of approximately
10 pounds per day of dry-cleaning waste and filters (reportedly redistilled prior to disposal to remove
perchloroethylene) and approximately 50 gallons per year of vehicular paint waste. Asbestos was
bagged and placed in a specific location and there were some rare occurrences of small arms and
explosives disposal. The report also stated that triple-rinsed punctured and crushed pesticide cans,
rags, and soil from small pesticide spills (less than 1 gallon) were disposed of.
Other waste disposed of in the Landfill includes drums and debris from the Utilidor Expansion Drums
Site; paint debris from Building 2077; more than 1,000 empty drums and two tanks from the Blair
Lakes Drums Site; approximately 1,000 drums of excavated material from the Glass Park Tar Site;
and the remnants of Building 2250, the Golf Course Pesticide Shed.
The active portion of the Landfill operates under a State of Alaska solid waste permit that allows the
disposal of domestic and commercial refuse, ash, asbestos, incinerator residue, bagged human waste,
and construction or demolition waste.
2.1.2 Coal Storage Yard Source Area
Activities at the CSV began in the 1950s with the industrial operation of the Post power plant. Based
on historical documents, the CSY's active coal pile was sprayed with waste petroleum fuel products
until 1993, when these practices were revised. As the active coal pile was consumed, the active pile
area was graded to include the top layer of soil and intermixed coal, and then burned in the power
plant. New coal supplies were then added to the storage yard.
Previous investigations have identified a fenced area, within the CSY, which contained a staging or
storage area for drums and where surface spills of materials were common. Leakage or spillage of
material from the drums may be another source of contamination. Two USTs within the fenced area
11
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contained waste POLs. Data collected during the 1995 investigation from the removal of the USTs
were incorporated into the RI.
2.1.3 Fire Training Pits Source Area
The FTPs were used for the training of fire department and rescue crews at Fort Wainwright.
Flammable liquids were containerized and stored at the various FTP sites and were burned during the
fire extinguishing training exercises. The specific substances and volumes that were incinerated at
each location were not recorded. Typically, the fuels included diesel, JP-4, waste oils, and solvents.
In general, the sequence of activities for FTP exercises included soaking pit soils with water; filling
the pit with fuels, brake fluid, and/or solvents; igniting the flammable mixture; and extinguishing the
resultant fire. The bottoms of the FTPs were not lined with impervious material when constructed.
FTP 3A contains a 50-foot-diameter circular area of black-stained soils. FTP 3B contains a
depression, approximately 5 to 10 feet in diameter, which is filled with gravel and small pieces of
concrete. It has been estimated that 1,500 to 2,300 gallons of flammable liquids were burned per
year in the FTPs. Construction of the pits included minor excavation on the relatively flat terrain,
with no surface water runoff diversion systems.
The contaminants at this source area consist of petroleum products, and they will be addressed
through an Army removal action that includes excavation and proper disposal of the petroleum-
contaminated soils. This is anticipated to be the final action for this source area. The Army Decision
Document for this action is contained in Appendix A. Therefore, the Fire Training Pits will not be
further discussed in this record of decision (ROD).
2.2 ENFORCEMENT ACTIVITIES
Fort Wainwright was placed on the CERCLA NPL in August 1990. Consequently, a Federal
Facilities Agreement (FFA) was signed in spring 1992 with the United States Environmental
Protection Agency (EPA), Alaska Department of Environmental Conservation (ADEC), and the
United States Department of Army. The FFA divided Fort Wainwright into five OUs, one of which
is OU-4, and outlines the general requirements for investigation and/or remediation of suspected
historical hazardous waste source areas and the associated procedures and schedules. It ensures that
appropriate actions are taken to protect public health and the environment in accordance with state and
federal laws.
An additional goal of the FFA was to integrate U.S. Army's CERCLA response obligations and
RCRA corrective action obligations. This enabled the Army to obtain an RCRA Part B permit for
interim status facilities. This was issued in spring 1992. Remedial actions implemented will be
protective of human health and the environment such that remediation of releases shall obviate the
need for further corrective actions under RCRA (i.e., no further corrective action shall be required)
for source areas.
2.3 HIGHLIGHTS OF COMMUNITY PARTICIPATION
The public was encouraged to participate in the selection of the remedies for OU-4 during a public
comment period from October 10 to November 10, 1995. The Fort Wainwright Proposed Plan for
Remedial Action Operable Unit 4 presented more than 10 combinations of options considered by the
United States Army, EPA, and ADEC to address contamination in soil and groundwater at OU-4.
12
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The Proposed Plan was released to the public on October 10, 1995, and was sent to all known
interested parties, which included approximately 150 elected officials and concerned citizens. An
informational Fact Sheet, dated September 1995, which provided information about the United States
Army's entire cleanup program at Fort Wainwright, was distributed to the same mailing list.
The Proposed Plan summarized available information regarding OU-4. Additional materials were
placed in two information repositories, one at the Noel Wien Library in Fairbanks and the other at the
Fort Wainwright Post Library. An Administrative Record, including all items placed in the
information repositories and other documents used in the selection of the remedial actions, was
established in Building 3023 on Fort Wainwright. The public was welcome to inspect materials
available in the Administrative Record and the information repositories during business hours.
Interested citizens were invited to comment on the Proposed Plan and the remedy selection process by
mailing comments to the Fort Wainwright project manager; calling a toll-free telephone number to
record a comment; or attending and commenting at a public meeting on October 17, 1995, in
Fairbanks at the Carlson Center. No comments were received from the public during the comment
period. Three people attended the public meeting.
Display advertisements in the Fairbanks Daily News-Miner, published on October 4, 8, 11, 15, 16,
and 17, 1995, also included information regarding the information repositories, the toll-free telephone
line, and an address for submitting written comments.
The Responsiveness Summary, Appendix B to this document, provides the background of community
involvement activities conducted in association with OU-4.
This decision document presents the selected remedial action for OU-4 chosen in accordance with
CERCLA as amended by the Superfund Amendments and Reauthorization Act of 1986 (SARA) and,
to the extent practicable, the National Contingency Plan (NCP). The decision for OU-4 is based on
the Administrative Record.
2.4 SCOPE AND ROLE OF OPERABLE UNIT OR RESPONSE ACTION
As with many Superfund sites, the problems at Fort Wainwright are complex. OU-4 will be the
second OU, following OU-3, at Fort Wainwright to have completed the RI/FS process and to begin
remedial action activities. The OU-4 RI and FS were performed in accordance with the RI/FS
Management Plan for OU-4. The RI fieldwork was conducted during September and October 1993,
and May and July 1994. The final RI, Risk Assessment, and FS reports were submitted to EPA and
ADEC in August and September 1995.
The remedial actions described in this ROD address threats to human health and the environment
posed by the contamination at the OU-4 source areas.
13
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3.0 SUMMARY OF SOURCE AREA CHARACTERISTICS
Physical features, hydrogeologic conditions, and the nature and extent of contamination for the
Landfill and CSV source areas are briefly described in the following sections.
3.1 LANDFILL SOURCE AREA
3.1.1 Physical Features, Hydrogeologic Conditions, and Transport Pathways
The RI for the Landfill source area included gathering information to characterize the hydrologic
setting, including permafrost conditions, and to identify contaminant transport pathways. The
presence of discontinuous permafrost at Fort Wainwright creates a very complex hydrologic system
that makes it extremely difficult to predict the direction and rate of groundwater movement, its
seasonal and annual changes or variability, and the factors critical to delineating groundwater
contaminant transport. Standard techniques, such as drilling and geological analysis as well as state-
of-the-art investigative methods, have been used at the Landfill to determine groundwater flow and
contaminant transport. Adequate and sufficient data were collected at the Landfill to support remedial
action decisions. Because of the complex nature of groundwater flow at the Landfill, further
investigations would have been expensive, would not resolve all uncertainties associated with
groundwater flow characteristics, and would not influence remedial options.
Permafrost varies in depth and thickness in areas surrounding the Landfill. Where permafrost is
present, the aquifer may exhibit shallow (suprapermafrost) and deep (subpermafrost) aquifer zones
that are two separate, distinct layers. Where permafrost is absent, as determined in thaw areas, these
two aquifer zones are linked together to create a single, unconfined aquifer. In the shallow zone,
contaminant transport may be inhibited by the onset of complete frost penetration by March or April,
preventing groundwater movement. In this aquifer zone, groundwater generally flows in the
southwest direction toward the Chena River. In the deep aquifer zone, groundwater generally flows
in the north-northwest direction consistent with the regional flow gradient. In both of these aquifer
zones, contaminant transport occurs year-round within talik (unfrozen) zones and near and beneath
surface water bodies.
Studies within the Landfill source area show permafrost-free zones beneath the Landfill, as a thaw
bulb, and discontinuously throughout the source area. It is unknown whether the thaw bulb beneath
the Landfill is continuous to bedrock because there were instrument resolution and drilling limitations.
Two thaw channels, which trend toward the Chena River located 1,500 feet downgradient of the
Landfill, were identified as transport pathways for groundwater contamination. They are located
downgradient on the southwest and southeast corners of the Landfill.
Groundwater hydraulic parameters were estimated using slug test data collected during the 1993
investigation and compared to pump test data reported in other investigations conducted near the
Landfill. Slug tests were performed at wells within the southwest drainage area, where groundwater
contaminant migration is considered most likely. Results indicate that potential groundwater flow
velocities range from 100 feet per year (ft/year) to 5,600 ft/year for groundwater in the upper aquifer
zone, and from 1,000 ft/year to 1,400 ft/year for groundwater in the lower aquifer zone.
Groundwater flow velocities fluctuate because of variations within the flow system, such as
heterogeneities in the lithology, permafrost, snowmelt recharge, precipitation events, or stage changes
in the Chena River. Groundwater flow within the southwest drainage area, where contamination is of
14
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primary concern, indicates a southwest flow direction at the water table and at depth trends toward
the regional flow direction of north-northwest. Influences from the Chena River stage changes are
expected to vary the flow direction and gradient seasonally.
The primary sources of contamination at the Landfill are wastes deposited in the Landfill and the coal
ash cover material generated at the power plant. Investigations confirmed that transport of Landfill
contaminants, including coal ash, through surface runoff from the Landfill to downgradient surface
water bodies is not significant. Creation of leachate, through percolation and infiltration of surface
water (i.e., rain or snowmelt) through Landfill waste, is believed to have caused groundwater
contamination.
While the contaminant plume could not be delineated at the Landfill source area, contaminant
transport pathways were identified. The two thaw channels were identified as transport pathways
from the source area. Other transport pathways may be present at the Landfill, but the complexity of
the hydrologic system limited characterization.
3.1.2 Nature and Extent of Contamination
Numerous investigations occurred at the Landfill before the start of the RI. From 1984 through
1989, investigations included installation of groundwater monitoring wells and completion of
electromagnetic surveys, which measured transmissivity and other aquifer characteristics to identify
potential leachate plumes.
In 1990, an extensive study that included analytical measurements of soil and water samples was
conducted. Several groundwater wells contained volatile organic compound (VOC) contamination.
Groundwater sampling was repeated in 1991 and 1992 with similar results. VOCs were detected in
shallow groundwater wells in the southwest thaw channel at concentrations that exceeded state and
federal water quality standards for trichloroethene (TCE) and 1,2-dichloroethene. Benzene and TCE
were also present in deeper groundwater wells within the southwest thaw channel at concentrations
below drinking water standards.
Principle objectives of the RI (1993 to 1994 sampling events) were to determine groundwater flow
direction, identify fate and transport pathways for contaminants from the Landfill, verify whether
groundwater monitoring wells were located within the most significant areas of contamination, and
identify potential contaminants of concern for the Baseline Risk Assessment.
In 1993, the RI included geophysical investigations and surface water, sediment, surface and
subsurface soil, and groundwater sampling investigations. During the RI, ash samples were collected
as surface samples from the daily cover material of the active Landfill. Additional surface soil and
sediment samples were collected based on field observations, such as stained soil and results of field
screening analyses. The 1994 investigation included gathering additional data to verify the
contaminant transport pathways; the existence, depth, and distribution of permafrost; and the
connections between the shallow and subpermafrost aquifer zones.
In order to determine groundwater flow direction, velocity, and contaminant concentrations,
monitoring wells were placed in the deep and shallow aquifer zones and near the Chena River. Water
level measurements were taken daily during the field season to determine local and regional
groundwater flow direction trends. Results from the RI indicated that groundwater geochemistry
15
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(i.e., total ionic content) hydraulically upgradient of the Landfill differs from the geochemistry
downgradient. This difference has been used to create a Landfill conceptual site model that predicts
that: a) leachate with a higher total ionic content than groundwater upgradient is being generated by
the Landfill, and b) the leachate is entering the shallow aquifer and causing the higher total ionic
concentrations in groundwater southwest of the Landfill.
The RI results confirmed VOC and semi-VOC contamination in groundwater, specifically benzene;
bis(2-ethylhexyl)phthalate; TCE; 1,1,2-trichloroethane; 1,1,2,2-tetrachloroethane (PCA); and cis-1,2-
dichloroethene (see Figure 3-1 and Table 3-1). These contaminants were found in the groundwater
under the Landfill and in the downgradient southwest transport pathway at concentrations exceeding
federal drinking water maximum contaminant levels (MCLs) and the risk-based screening
concentration developed by EPA, Region 3. These groundwater contaminant concentrations are
indicative of a contaminant source within the Landfill area. Table 3-2 (AP-5588 and AP-5589)
illustrates that the concentrations of groundwater contaminants in the southwest drainage have
remained relatively constant since sampling began in 1990. Some of the groundwater contaminants
detected are intermediate breakdown products of PCA, which was disposed of in the Landfill.
Inorganic analytes were retained as contaminants of concern if they exceeded background and/or risk-
based concentrations (RBCs) or MCLs. Two metals, lead and chromium, exceeded an MCL or RBC,
but were below background levels and therefore not considered further. Also found in the
groundwater were two metals, arsenic and manganese, at concentrations exceeding MCLs or RBCs
and established background levels. However, these numbers reflect naturally occurring concentrations
in this mineralogically rich area. During a well survey performed by the United States Geological
Survey in the Fairbanks area in 1993, arsenic concentrations in groundwater were found to range
from 0 to 5,100 micrograms per liter (/ig/L). Arsenic concentrations in groundwater in the Fairbanks
area exceeded the 50 /ig/L drinking water standard in 13% of the wells sampled, all attributable to
natural conditions.
The southwest thaw channel intersects the Chena River. Groundwater contaminants in this transport
pathway may enter the Chena River or threaten downgradient groundwater users including residents
of the City of Fairbanks. Groundwater contaminant transport was evaluated using a simplistic
groundwater transport model to estimate transport distance from the Landfill. The model estimated
that solvent concentrations would reach federal MCLs at a point beyond the Chena River when
traveling downgradient from the Landfill.
Based on the RI, petroleum contaminants, specifically bunker fuel and total recoverable petroleum
hydrocarbons (TRPH), exist in one discrete surface soil location as a result of a spill. Associated
with that spill is a high concentration of lead. This surface soil spill is located in the inactive portion
of the Landfill; however, this small location subsequently was covered permanently with
approximately 8 feet of construction debris and native soil during the active landfilling stabilization
effort conducted in summer 1995. The covering of the spill eliminated the dermal exposure pathway
for the lead.
3.2 COAL STORAGE YARD SOURCE AREA
3.2.1 Physical Features, Hydrogeologic Conditions, and Transport Pathways
Permafrost is present on the south side of the Chena River; however, it was not encountered during
investigations at the CSV and is not expected to significantly affect groundwater contaminant transport
16
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pathways. Groundwater occurs at a depth of approximately 11 to 12 feet below ground surface
(BGS), although seasonal variations of several feet occur. Groundwater flow is toward the northwest,
which is consistent with the regional flow direction. Water supply wells for Fort Wainwright are
located downgradient of the CSV source area and are approximately 900 feet northwest of the active
coal pile. Hydraulic parameters were estimated in a similar fashion as with the Landfill source area.
Slug-tests were conducted to estimate hydraulic properties. Flow velocities based on measured
gradients were estimated to range widely from 243 ft/year to 2,917 ft/year. The cooling pond, which
is an unlined excavation adjacent to the active coal pile, is hydrologically connected to the
groundwater aquifer and may affect groundwater flow. This was observed during a heavy rainfall in
September 1993 when adjacent wells responded with higher relative water levels than wells farther
from the cooling pond. In addition, the groundwater elevation was the same as the cooling pond
level.
Original contaminant sources at the CSV included diesel fuels, solvents, and lubricants sprayed on the
active coal pile and waste oil spills and leaks from tanks and drums. Soils contaminated with these
chemicals continue to be a source of groundwater contamination. Contaminants have been transported
by overland flow of surface water (i.e., rain or snowmelt), vertical migration through soils to the
groundwater aquifer, and volatilization. The power plant cooling pond receives runoff from the coal
pile and surrounding coal yard during periods of heavy rainfall and during snowmelt. The cooling
pond is located directly west of the storage yard and surrounded by drainage ditches. Vertical
migration of contaminants from soil to groundwater is confirmed by the presence of organics such as
bis(2-ethylhexyl)phthalate and xylenes in soil and groundwater. Soils are very porous and
transmissive, allowing infiltration to occur readily. Solubility of the contaminants makes them subject
to further migration via infiltration.
Elevated groundwater temperatures resulting from the discharge of plant effluent to the cooling pond
may volatilize contaminants. Volatilization in the cooling pond area may occur until groundwater
movement of the contaminants encounters "cooler" groundwater temperatures away from the
influence of the cooling pond. With groundwater temperatures averaging 25° Celsius (C), which is
approximately 20°C higher than other areas at Fort Wainwright, volatilization is a likely transport
mechanism. Heat rising from the groundwater elevates temperatures in the upper soils within the
vadose zone, possibly causing volatilization.
3.2.2 Nature and Extent of Contamination
Numerous investigations had occurred at the CSV before the start of the RI. From 1986 to 1991, soil
borings and monitoring wells were installed in the CSY vicinity and samples were collected. Soil
contaminants detected included DDT, petroleum, benzene, TCE, and other semi-VOCs. Levels of
antimony and mercury exceeded background concentrations. Contaminants detected at concentrations
below MCLs during groundwater sampling include DDD; endrin; 1,1-dichloroethene; 1,1,1-
trichloroethane; and xylenes. Soils within the center of the active coal pile contained the highest
concentrations of semi-VOCs. Because the area is actively being used as a coal yard, it was difficult
to obtain groundwater samples in the most likely contaminated areas.
In 1993 and 1994, the RI for OU-4 was conducted. The principal objectives were to obtain
information about the extent of contamination and to determine the extent of contaminant migration
downgradient toward Fort Wainwright drinking water wells. The OU-4 RI field investigation
consisted of the following tasks: geophysical survey, field laboratory screening, geoprobe
17
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investigation, Microwell sampling, surface and subsurface soil investigations, groundwater monitoring
well installation and sampling, surface water and sediment sampling, and aquifer testing.
One round of field sampling was conducted during the RI to identify areas of highest contamination.
Groundwater monitoring wells were then installed, and samples of sufficient data quality for a
Baseline Risk Assessment were collected.
Groundwater monitoring wells were installed in several nested locations to meet objectives of the RI.
This included installation of three nested well sets downgradient of the CSV and upgradient of the
Post potable water supply wells. These wells were installed to ensure early detection of off-source
contaminant migration. They were installed at the water table and at depths up to 181 feet BGS to
match the depths of the water supply wells.
At the time of the RI, ongoing activities at the power plant required a pile of coal approximately 40
feet high. This coal pile was and still is located on the area used for previous coal pile spraying of
fuels and was suspected as being the most contaminated. This precluded installing traditional
monitoring wells. Groundwater sampling wells were installed in this area using a drive-point well
technique (i.e., Microwells). This allowed for groundwater sampling in areas difficult to access via
traditional techniques. Although this technology does not allow for traditional well development,
these samples were analyzed in accordance with risk assessment protocol.
Surface and subsurface soil samples were collected in locations identified from field screening
samples. The ongoing industrial operation at the power plant made it difficult to collect
representative samples in the source area. VOC contaminants found in soils at the CSV area,
specifically benzene, toluene, ethylbenzene, and total xylenes (BTEX) in the subsurface soil, exceed
State cleanup levels (see Figure 3-2). Petroleum contaminants detected in soils at the CSV area also
exceed State cleanup levels, specifically bunker fuel and diesel-range organics in the surface soil and
TRPH in both the surface and subsurface soil. These contaminated soils are considered a potential
ongoing source of contamination to groundwater. Tables 3-3 through 3-5 for the CSV show 1993
groundwater sampling results. These three tables represent data from three separate sampling
methods and events. Table 3-6 is a summary of 1994 groundwater results.
Petroleum-related contaminants in the groundwater at the CSV area extend from the background well,
southeast of the CSY area, to the wells north of the power plant and west of the cooling pond. VOC
contamination in the groundwater appears to be limited laterally to the area under the active coal pile
and fenced storage yard, based on monitoring well, GeoProbe, and Microwell groundwater samples.
Based on Microwell groundwater samples, BTEX and other benzene compounds appear to be limited
to the area directly under the active coal pile. No floating product was encountered (light nonaqueous
phase liquid). In addition to contamination at the groundwater interface, contamination was
characterized at depth beneath the coal pile. Solvent concentrations in the aquifer do not indicate the
presence of a free-product source (dense nonaqueous phase liquid). VOC groundwater contamination
found in the CSY area, specifically benzene, toluene, TCE, and semi-VOC contamination, more
specifically bis(2-ethylhexyl)phthalate, exceeds risk-based screening concentrations (see Figure 3-3).
Inorganic analytes were retained as contaminants of concern if they exceeded background and/or
RBCs or MCLs. Two metals, lead and barium, exceeded an MCL or RBC, but were below
background levels and therefore not considered further. RBCs for two metals, antimony and
manganese, were exceeded; however, these numbers reflect naturally occurring concentrations in this
mineralogically rich area.
18
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Page 1 of 4
Table 3-1
SUMMARY OF 1993 GROUNDWATER RESULTS
LANDFILL SOURCE AREA
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Analyte and
Concentration Units
No. of Samples
Analyzed8/
Detected
Range of Detected
Concentrations
Location of
Maximum
Concentration
Alaska Water
Quality Criteria
(18 AAC 70)/MCL
(18 AAC 80)
10"6
Risk-based
Cone.'
Background
Conc.b
Total Metals 0
-------
Page 2 of 4
to
O
Table 3-1
SUMMARY OF 1993 GROUNDWATER RESULTS
LANDFILL SOURCE AREA
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Analyte and
Concentration Units
Dissolved Metals (/ig/L)
Arsenic
Barium
Zinc
No. of Samples
Analyzed*/
Detected
Range of Detected
Concentrations
Location of
Maximum
Concentration
Alaska Water
Quality Criteria
(18 AAC 70)/MCL
(18 AAC 80)
20/7
20/15
20/2
6-74*°
110-550°
70-90
AP-6139
AP-5589
AP-6138
50/50
1,000/2,000
47/5,000(s)
to-6
Risk-based
Cone."
Background
Conc.b
0.038
260
1,100
20°
341C
50 U
General Water Parameters G«g/L)
Alkalinity (Total)
Alkalinity (CaCO3)
Biochemical oxygen demand
Chloride
Fluoride
Nitrate
Nitrate/Nitrite
Orthophosphate
Sulfate
Total dissolved solids
Total organic carbon
Total suspended solids
20/20
20/20
20/2
20/19
20/11
20/12
20/12
20/19
20/20
20/20
20/20
22/3
20,000-370,000
20,000-370,000
6,000-7,000
1,100-46,000
100-980°
40-130
40-150
30-660
4,200-250,000
120,000-800,000
3,200-16,000
19,000-460,000
AP-6139
AP-6139
AP-6138
AP-5588
AP-6138
AP-6132
AP-6133
WLF-03
AP-6139
AP-6139
AP-6133
AP-5591
<20,000/-
/
/
— /250,000(s)
2,400/4,000
10,000/10,000
10,000/10,000
/
-/250,000(s)
-/500,000(s)
/
__/
—
—
—
—
220
5,800
370
—
—
—
—
—
170,000
170,000
5,000 U
1,100
100
130
130
110
1,600
240,000
7,000
—
* Groundwater concentration of detected analyte exceeded MCLs.
° Groundwater concentration of detected analyte exceeded risk-based concentration of
Key at end of table.
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Page 3 of 4
Table 3-1
SUMMARY OF 1993 GROUNDWATER RESULTS
LANDFILL SOURCE AREA
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Analyte and
Concentration Units
No. of Samples
Analyzed8/
Detected
Range of Detected
Concentrations
Location of
Maximum
Concentration
Alaska Water
Quality Criteria
(18 AAC 70)/MCL
(18 AAC 80)
lO"6
Risk-based
Cone."
Background
Conc.b
Volatile Organic Compounds (/ig/L)
Acetone
Benzene
Bromodichloromethane
Chloroform
Dichlorodifluoromethane
1 ,2-Dichloroethane
cis-1 ,2-Dichloroethene
trans- 1 ,2-Dichloroethene
Methylene chloride
1 , 1 ,2,2-Tetrachloroethane
Tetrachloroethene
1 , 1 ,2-Trichloroethane
Trichloroethene
Vinyl chloride
20/5
20/2
20/2
20/3
20/2
20/2
20/3
20/3
20/5
20/2
20/1
20/1
20/3
20/2
17-87
3.3-4.4°
1.7-2.9°
2.5-33°
4.1-5.5
3.3-5.1*°
4.5-130*°
2.0-40°
1-1.7
6.3-1,300°
1.4
8.1*°
3.6-170*
1.0-1.3°
FWLF-03
AP-5589
AP-6138
AP-6138
AP-5589
AP-5589
AP-5588
AP-5588
FWLF-2
AP-5588
AP-5588
AP-5588
AP-5588
AP-5589
_J_
5/5
11,000/100
1,240/100
100C/
5/5
/70
/100
_J5
2,400/
840/5
9,400/5
5/5
2/2
370
0.36
0.17
0.15
39
0.12
6.1
12
4.1
0.052
6.1
0.19
—
0.019
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Semivolatile Organic Compounds (/tg/L)
Bis(2-ethylhexyl)phthalate
20/8
8.9-620*°
AP-6136
/6
4.8
NA
* Groundwater concentration of detected analyte exceeded MCLs.
0 Groundwater concentration of detected analytc exceeded risk-based concentration of 10"6.
Key at end of table.
-------
Page 4 of 4
K)
N)
Table 3-1
SUMMARY OF 1993 GROUNDWATER RESULTS
LANDFILL SOURCE AREA
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Analyte and
Concentration Units
No. of Samples
Analyzed8/
Detected
Range of Detected
Concentrations
Location of
Maximum
Concentration
Alaska Water
Quality Criteria
(18 AAC 70J/MCL
(18 AAC 80)
10-*
Risk-based
Cone."
Background
Conc.b
Fuels (/«g/L)
Bunker C-range organics
Diesel No. 2
Gasoline
Diesel-range organics
TRPH (oil and grease)
20/11
20/1
20/7
2/2
20/2
110-1,700
420
110-140
120-120
70-90
AP-6138
AP-5589
FWLF-04
WLF-03
AP-6138
/
_/_
__/_
/
/
—
—
—
—
—
NA
NA
NA
NA
NA
a United States Environmental Protection Agency, Region 3, Risk-based Concentration Table, Fourth Quarter 1994, November 1994. Cancer risk = 10 .
Hazard quotient = 0.1.
® Groundwater background concentrations derived from sample location AP-6132, unless otherwise noted.
^ Groundwater background concentrations provided by the Corps.
" Criterion is hardness dependent for 18 AAC 80, Alaska Water Quality Standards.
* Groundwater concentration of detected analyte exceeded MCLs.
0 Groundwater concentration of detected analyte exceeded risk-based concentration of Iff6.
Key:
— = Value not established.
Cone. = Concentration.
ftg/L = Micrograms per liter.
MCL = Maximum contaminant level.
NA = Not applicable.
(s) = Secondary MCL.
TRPH = Total recoverable petroleum hydrocarbons.
U = Not detected.
-------
Page 1 of 2
M
u>
Table 3-2
VOLATILE ORGANIC COMPOUNDS OF CONCERN
RESULTS FROM 1990 TO 1994
AP-5588 AND AP-5589
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
(Mg/L)
Well
AP-5588
AP-5589
Contaminant
Vinyl Chloride
Carbon Disulfide
1,2-Dichloroethene (total)
1 , 1-Dichloroethane
Benzene
1 ,2-Dichloroethane
Trichloroethene
1 ,2-Dichloropropane
Toluene
1 ,1 ,2-Trichloroethane
Tetrachloroethene
Ethyl Benzene
Total Xylenes
1 , 1 ,2,2-Tetrachloroethane
Vinyl Chloride
Carbon Disulfide
1,2-Dichloroethene (total)
4/90c
ND
ND
470*
ND
5*
ND
250*
ND
ND
ND
ND
ND
ND
ND
ND
ND
29
8/91
1.1
0.1
338.5*
0.4
2.9
0.4
224*
2.7
0.1
14*
2.1
0.2
0.4
1,960*
1.9
0.2
19.4
10/91
ND(5)
ND(5)
60
ND(5)
ND(5)
ND(5)
220*
ND(5)
ND(5)
330*
ND(5)
ND(5)
ND(5)
2,100*
ND(5)
ND(5)
ND(5)
4/92
2.6*
ND(O.l)
450*
ND(O.l)
4.5
ND(O.l)
240*
ND(O.l)
ND(O.l)
11.4*
3.3
ND(O.l)
ND(O.l)
1,000*
3*
ND(O.l)
36.6
9/92
1.2
ND(0.5)
282*
0.6
3.7
3.2
210*
ND(0.5)
ND(0.5)
ND(0.5)
2.5
ND(0.5)
ND(0.5)
15,000*
1.5
ND(0.5)
23.9
9/93
1.3
NA
170*
ND(l.O)
3.3
3.3
170*
ND(l.O)
ND(l.O)
8.1*
1.4
ND(1 .0)
ND(l.O)
1,300*
1.0
NA
12.6
7/94
ND
ND(3.0)
201*
ND(3.0)
4.5
4.5
180*
ND(3.5)
ND(2.0)
9.9*
ND(1.7)
ND(1.6)
ND(6.5)
1,000*
ND(3.0)
ND(5.8)
23.9
MCL
(18 AAC 80)
2
5
70
—
5
5
5
5
1,000
5
5
700
10,000
RBC 10-4=5.2
2
5
—
Key at end of table.
-------
Page 2 of 2
NJ
Table 3-2
VOLATILE ORGANIC COMPOUNDS OF CONCERN
RESULTS FROM 1990 TO 1994
AP-5588 AND AP-5589
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
(Atg/L)
Well
Contaminant
Benzene
1 ,2-Dichloroethane
Trichloroethene
1 ,2-Dichloropropanc
1 , 1 ,2,2-Tetrachloroethane
4/90c
6*
ND
7*
ND
ND
8/91
6.7*
4.2
5.6*
0.4
1.0
10/91
6.7*
ND(5)
5.8*
ND(5)
ND(5)
4/92
7.9*
ND(O.l)
7.5*
ND(O.l)
ND(O.l)
9/92
5.6*
5.2*
5.3*
ND(0.5)
1.8
9/93
4.4
5.1*
4.7
ND(l.O)
6.3
7/94
6.3*
5.1*
7.3*
ND(3.5)
5.9
MCL
(18 AAC 80)
5
5
5
5
—
a United States Environmental Protection Agency, Region 3, Risk-based Concentration Table, Fourth Quarter 1994, November 1994. Cancer
risk = 10"7. Hazard quotient = 0.1.
" Maximum contaminant level.
c Detection limits are unavailable for this data set.
* Groundwater concentration of detected analyte exceeds maximum contaminant level.
Key:
MCL = Maximum contaminant level.
NA = Not applicable
ND = Not detected.
/ig/L = Micrograms per liter.
— = Value not established.
-------
Page 1 of 2
Table 3-3
1993 FIELD SCREENING VOLATILE ORGANIC COMPOUND RESULTS
COAL STORAGE YARD SOURCE AREA
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Matrix
Surface Soil (mg/kg)
Subsurface Soil (mg/kg)
Groundwater (/tg/L)
Analyte
o-Xylene
PCE
Benzene
Toluene
Ethylbenzene
Chlorobenzene
m & p-Xylenes
o-Xylene
1,1 -DCE
TCE
1,1,1-TCA
1,1,2-TCA
PCE
Benzene
Toluene
Ethylbenzene
m&p-Xylenes
o-Xylene
Total Xylenes
1,1-DCA
TCE
1,1,1-TCA
1,1,2-TCA
PCE
1,1,2,2-PCA
Number of
Samples
Analyzed/
Detected
5/1
5/1
71/11
71/9
71/11
71/3
71/7
71/8
71/9
71/11
71/4
71/1
71/11
84/9
84/9
84/8
84/8
84/9
84/9
84/5
84/9
84/3
84/1
84/7
84/3
Range of
Detected
Cone.
0.0068
0.018
0.0144-22.3°
0.0057-16.4
0.0104-18.7
0.0199-0.0429
0.0059-0.190
0.0124-0.396
0.0153-0.279°
0.0181-186
0.560-38.1
0.054
0.0052-1.1
6.8-870*°
6.1-2,550*°
5.5-550°
9.1-790°
6.0-1,020°
6.0-1,810
13.1-196°
5.8-820*
46.5-653
25.8°
6.0-410*°
5.9-653°
Risk-Based
Conc.a/MCL
16,000/NA
78/NA
2.2/NA
1,600/NA
780/NA
160/NA
16,000/NA
16,000/NA
0.110/NA
-/NA
— /NA
1.1/NA
78/NA
0.36/5
75/1,000
130/700
140/10,000
140/10,000
280/20,000°
81/-
-15
-/—
0.19/—
6.1/5
0.052/—
a United States Environmental Protection Agency, Region 3, Risk-based Concentration Table, Fourth Quarter
1994, November 1994. Cancer risk for soils = 1 x 10"7. Cancer risk for groundwater = 1 x 10"6. Hazard
quotient = 0.1.
* Groundwater concentration of detected analyte exceeds MCL.
° Groundwater concentration of detected analyte exceeds risk-based concentration of Iff6.
Key at end of table.
25
-------
Page 2 of 2
Table 3-3 (Cent.)
Key:
1,1-DCA = 1,1-Dichloroethane.
1,1-DCE = 1,1-Dichloroethene.
MCL = Maximum contaminant level.
mg/kg = Milligrams per kilogram.
NA = Not applicable.
1,1,2,2-PCA = 1,1,2,2-Tetrachloroethane.
PCE = Tetrachloroethene.
1,1,1-TCA = 1,1,1-Trichloroethane.
1,1,2-TCA = 1,1,2-Trichloroethane.
TCE = Trichloroethene.
/tg/L = Micrograms per liter.
— = Value not established.
26
-------
Page 1 of 1
Table 3-4
1993 MICROWELL ANALYTICAL RESULTS
COAL STORAGE YARD SOURCE AREA
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
G*g/L)
Analyte
1,1,1-Trichloroethane (TCA)
1 , 1 -Dichloroethane
1 ,2-Dichloroethane
Benzene
cis-1 ,2-Dichloroethene
Ethylbenzene
Tetrachloroethene (PCE)
Toluene
Total Xylenes
Trichloroethene (TCE)
No. of Samples
Analyzed/
Detected
30/3
30/2
30/1
30/17
30/5
30/11
30/3
30/9
30/12
30/6
Range of
Detected
Concentrations
3.8-65
1-8.1
0.5-0.5°
0.5-800*°
0.7-6.8°
1-650°
1.7-4.3
1-2,300*°
2-3,200°
0.6-1.4
Location of
Maximum
Result
PS-4
PS-2
PS-2
PS-4
PS-2
PS-4
PS-4
PS-4
PS-4
PS-4
10"6 Risk-
Based
Conc.a/MCL
-/-
81/-
0.12/-
0.36/5
6.1/70
130/700
6.1/5
75/1,000
1,200/10,000
— /5
United States Environmental Protection Agency, Region 3, Risk-based Concentration Table, Fourth Quarter 1994,
November 1994. Cancer risk = 1 x 10"6. Hazard quotient = 0.1.
* Groundwater concentration of detected analyte exceeds MCL.
° Groundwater concentration of detected analyte exceeds risk-based concentration of 10"^.
Key:
Cone. = Concentration.
MCL = Maximum contaminant level.
= Micrograms per liter.
— = Value not established.
27
-------
Page 1 of 6
oo
Table 3-5
SUMMARY OF 1993 GROUNDWATER RESULTS
COAL STORAGE YARD SOURCE AREA
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Analyte and
Concentration Units
No. of Samples
Analyzed/
Detected
Range of Detected
Concentrations
Location of
Maximum
Concentration
Alaska Water
Quality
Criteria/MCL
UK6
Risk-based
Concentration8
Background
Concentration11
Total Metals (jtgIL)
Arsenic
Barium
Calcium
Copper
Iron
Lead
Magnesium
Manganese
Nickel
Sodium
Zinc
20 / 17
20/20
20 / 15
20 / 13
30/3
20 / 12
3/3
3/3
20 / 12
3 /3
20 / 18
3-59*°
96-500°
42,100-211,000*
6-110
10,900-48,400*
1.6-20*°
30,700-49,200
1,100-2,000*°
11-38
6,100-8,600
7-120
AP-5509
AP-5517
3595-02
AP-5510
3595-03
AP-6141
3595-02
3595-01
AP-6141
3595-03
AP-5509-3559A
50/50
1,000 / 2,000
— / 2,000
12 / 1,300
l,000/300(s)
3.2 / 15
— / —
- / 50(s)
96 / 100
-/-
47 / 5,000(s)
0.038
260
—
—
—
—
—
18
73
—
1,100
72c
988C
71,300d
68
—
66C
—
—
38
—
97
Dissolved Metals (jigIL)
Arsenic
Antimony
Barium
20 / 10
20/5
20/20
4-12°
26-37
80-300°
AP-5735
AP-5508
AP-5737
50/50
1,600/6
1,000/2,000
0.038
1.5
260
20C
25U
341C
* Groundwater concentration of detected analytes exceeds maximum contaminant concentrations.
0 Groundwater concentration of detected analytes exceeds risk-based concentration of 10"6.
Key at end of table.
-------
Page 2 of 6
Table 3-5
SUMMARY OF 1993 GROUNDWATER RESULTS
COAL STORAGE YARD SOURCE AREA
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Analyte and
Concentration Units
Copper
Iron
Lead
Magnesium
Manganese
Nickel
Sodium
Zinc
No. of Samples
Analyzed/
Detected
20 / 1
177 13
20/2
17 / 17
17 / 17
20/4
17 / 17
17/3
Range of Detected
Concentrations
6
75-15,900*
4-10
9,900-44,800
60-920*°
16-20
4,200-29,600
18-22
Location of
Maximum
Concentration
3559A
AP-5735
3595-02
AP-5517
AP-5511
3595-02
AP-5517
3595-03
Alaska Water
Quality
Criteria/MCL
12 / 1,300
l,000/300(s)
3.2 / 15
— / —
— / 50(s)
96 / 100
/
47 / 5,000
ivr6
Risk-based
Concentration8
140
—
15
—
18
73
—
1,100
Background
Concentration"
5U
1,700
9.9C
23,400
780
10U
6,600
5U
Organics (/tg/L)
bis(2-Ethylhexyl)phthalate
di-n-Butylphthalate
Dieldrin
Heptachlor
Heptachlor epoxide
m&p-Xylene
Methoxychlor
20/4
20 / 19
20/2
20 / 1
20/2
20/3
20/3
2-110*°
1-13
0.01-0.021°
0.08°
0.01-0.02°
2.0
0.044-0.16
AP-6142
AP-5511
119
3595-02
119
3595 / 01 / 02 / 03
119
-16
— I —
— / —
0.0038 / 0.4
— /0.2
— / —
0.03 / 40
4.8
370
0.0042
0.0023
0.0012
52
18
NA
NA
NA
NA
NA
NA
NA
* Groundwater concentration of detected analytes exceeds maximum contaminant concentrations.
° Groundwater concentration of detected analytes exceeds risk-based concentration of 10"*.
Key at end of table.
-------
Page 3 of 6
u>
o
Table 3-5
SUMMARY OF 1993 GROUNDWATER RESULTS
COAL STORAGE YARD SOURCE AREA
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Analyte and
Concentration Units
Methylene chloride
o-Xylene
Trichloroethene
Trichlorofluoromethane
No. of Samples
Analyzed/
Detected
20/2
20/3
20/2
20 / 1
Range of Detected
Concentrations
4-6*°
1.0
7-56
29
Location of
Maximum
Concentration
3595-01
3595-01 / 02 / 03
3595-01
3595-03
Alaska Water
Quality
Criteria/MCL
— 15
— / —
5/5
11,000 I —
lo-6
Risk-based
Concentration"
4.1
140
—
2,300
Background
Concentration11
NA
NA
NA
NA
Fuels G«g/L)
TRPH
Diesel No. 2
Bunker Oil (No. 6 Diesel)
20 / 12
20 / 1
20/9
25-2,000
310
390-1,100
AP-6143
AP-6142
AP-6142
— i —
-1 -
-I -
—
—
—
NA
NA
NA
Other fcig/L)
Alkalinity (CaCO3)
Chloride
Fluoride
Orthophosphate
Silica
Sulfate
Total organic compounds
20/20
20/20
20/5
20 / 11
20/20
20/20
20/20
122,000-590,000
1,800-102,000
130-260
52-260
8,200-20,900
9,600-152,000
7,100-145,000
3595-02
AP-5517
3559A / B
AP-5509
AP-6142
3595-02
3595-02
-1 -
— 1 250,000(s)
2,400 / 4,000
— / —
1
- / 250,000(s)
— / —
—
—
—
—
—
—
—
NA
8,300
500
68
12,700
NA
NA
* Groundwater concentration of detected analytes exceeds maximum contaminant concentrations.
0 Groundwater concentration of detected analytes exceeds risk-based concentration of 10^.
Key at end of table.
-------
Page 4 of 6
Table 3-5
SUMMARY OF 1993 GROUNDWATER RESULTS
COAL STORAGE YARD SOURCE AREA
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Analyte and
Concentration Units
Total dissolved solids
Biochemical oxygen demand
Nitrate-Nitrate
No. of Samples
Analyzed/
Detected
20/20
20 / 11
20 / 10
Range of Detected
Concentrations
68,000-1,780,000
1,300-654,000
27-5,300"
Location of
Maximum
Concentration
AP-5509
AP-5510
AP-5517
Alaska Water
Quality
Criteria/MCL
— /-
— / —
10,000 / 10,000
10"6
Risk-based
Concentration8
—
—
370
Background
Concentration"
NA
NA
64
Dioxin/Furans (pg/L)
1,2,3,4,6,7,8,9-OCDD
1,2,3,4,6,7,8,9-OCDF
1,2,3,4,6,7,8-HpCDD
1,2,3,4,6,7,8-HpCDF
1,2,3,4,7,8-HxCDF
1,2,3,6,7,8-HxCDF
1,2,3,7,8,9-HxCDD
1,2,3,7,8,9-HxCDF
1,2,3,7,8-PeCDD
2,3,4,6,7,8-HxCDF
Total HpCDD
Total HpCDF
20/3
20 / 1
20/3
20/2
20 / 1
20/3
20 / 1
20 / 1
20 / 1
20/2
20/3
20/2
48.6-77.7
5.46
10.7-18.3
2.82-4.28
2.43
0.943-1.45
1.34
0.971
1.95°
3.26-3.42
18.3-24.9
3.14-4.75
3595-03
3595-01
3595-03
3595-03
3595-03
3595-03
3595-02
3595-02
3595-02
3595-03
3595-02
3595-03
— / 30,000
— / 30,000
— / 3,000
— / 3,000
— /300
-/300
— /300
— /300
— /60
-/300
/
— /-
430
430
43
43
4.3
4.3
4.3
4.3
0.86
4.3
—
—
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
* Groundwater concentration of detected analytes exceeds maximum contaminant concentrations.
0 Groundwater concentration of detected analytes exceeds risk-based concentration of 10"6.
Key at end of table.
-------
Page 5 of 6
Table 3-5
SUMMARY OF 1993 GROUNDWATER RESULTS
COAL STORAGE YARD SOURCE AREA
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Analyte and
Concentration Units
Total HxCDD
Total HxCDF
Total PeCDD
Total PeCDF
Total TCDF
No. of Samples
Analyzed/
Detected
20/2
20/2
20/3
20 / 1
20/2
Range of Detected
Concentrations
2.53-9.4
0.997-19.9
1.95-1.95
4.01-55.4
0.674-19.3
Location of
Maximum
Concentration
3595-02
3595-02
3595-02
3595-02
3595.02
Alaska Water
Quality
Criteria/MCL
/
-/-
— / —
-/-
-/-
lO"6
Risk-based
Concentration8
—
—
—
—
—
Background
Concentration"
NA
NA
NA
NA
NA
U)
a United States Environmental Protection Agency, Region 3, Risk-based Concentration Table, Fourth Quarter 1994, November 1994. Cancer risk = 1 X 10" . Hazard quotient = 0.1.
" Background data from sample locations AP-5734 and AP-6141, unless otherwise noted.
c Background data provided by the Corps.
** Background data from sample location AP-5734 only.
* Groundwater concentration of detected analytes exceeds maximum contaminant concentrations.
0 Groundwater concentration of detected analytes exceeds risk-based concentration of 10"6.
Key at end of table.
-------
Page 6 of 6
Table 3-5 (Cent.)
00
u>
Key:
HpCDD
HpCDF
HxCDD
HxCDF
MCL
NA
OCDD
OCDF
PeCDD
pg/L
(s)
TRPH
U
= Heptachlorodibenzo-p-dioxin.
= Heptachlorodibenzofuran.
= Hexachlorodibenzo-p-dioxin.
= Hexachlorodibenzofuran.
= Maximum contaminant level.
= Micrograms per liter.
= Not applicable.
= Octachlorodibenzo-p-dioxin.
= Octachlorodibenzoftiran.
= Pentachlorodibenzo-p-dioxin.
= Picograms per liter.
= Secondary MCL.
= Total recoverable petroleum hydrocarbons.
= Not detected.
= Value not established.
-------
Page 1 of 3
*>.
Table 3-6
SUMMARY OF 1994 GROUNDWATER RESULTS
COAL STORAGE YARD SOURCE AREA
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Analyte and
Concentration Units
Number of
Samples
Analyzed/
Detected
Range of Detected
Concentrations
Location of
Maximum
Concentration
Alaska Water
Quality
Criteria/MCL
lO"6
Risk-based
Concentration8
Background
Concentration"
Total Metals (pg/L)
Arsenic
Lead
Selenium
Zinc
8/8
8/2
8/ 1
8 12
2.3 - 8.4°
1.6-6.8
3.8
6.2 - 6.4
AP-6523
AP-6520
AP-6524
AP-6519
50/50
3.2 / 15
1
47 / 5,000(s)
0.038
15
—
1,100
72C
66C
—
97
Dissolved Metals G»g/L)
Arsenic
Selenium
Zinc
8/8
8/ 1
8 /4
1.5 - 13.0°
3.4
12-20
AP-6522
AP-6524
AP-6521
50/50
— / —
47 / 5,000
0.038
—
1,100
20C
—
5U
Organks (/tg/L)
bis(2-Ethylhexyl)phthalate
di-n-Butylphthalate
Dieldrin
Heptachlor
7/3
11
1 1
/I
2J - 13*°
2JB - 5JB
0.03°
0.04"
AP-6521
AP-6521
AP-6522
AP-6522
-16
-/-
-/2.0
3.8/0.4
4.8
370
0.0042
0.0023
NA
NA
NA
NA
* Groundwater concentration of detected analyte exceeds MCLs.
0 Groundwater concentration of detected analyte exceeds risk-based concentration of 10"6.
Key at end of table.
-------
Page 2 of 3
Table 3-6
SUMMARY OF 1994 GROUNDWATER RESULTS
COAL STORAGE YARD SOURCE AREA
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Analyte and
Concentration Units
Methylene chloride
Trichloroethene
Trichlorofluoromethane
Number of
Samples
Analyzed/
Detected
10/3
5/2
51 1
Range of Detected
Concentrations
3JB
9- 11*°
140
Location of
Maximum
Concentration
AP-5735
3595-01
3595-03
Alaska Water
Quality
Criteria/MCL
— 15
5 15
11,000 / —
1Q-6
Risk-based
Concentration*
4.1
—
2,300
Background
Concentration1*
NA
NA
NA
Fuels 0*g/L)
TRPH (Mod 8015)
DRO
Bunker Oil (No. 6 Diesel)
3 12
3/2
< 100,000 - 320,000
250,000
AP-6523
3595-03
AP-6523, AP-6521
-/-
-/-
— / —
—
—
—
NA
NA
NA
Other Gtg/L)
Benzene
Chloroform
4,4-DDE
cis-1 ,2-dichloroethylene
Endrin Ketone
5/1
10/6
/I
51 1
/I
3J*°
7B - 10B
0.09
2J
0.14
3595-03
AP-6140
AP-6522
3595-03
AP-6522
5/5
1,2407 100
0.001 / —
-770
-/-
0.36
0.15
0.2
6.1
—
NA
NA
NA
NA
NA
OJ
Ul
* Groundwater concentration of detected analyte exceeds MCLs.
0 Groundwater concentration of detected analyte exceeds risk-based concentration of 10"6.
Key at end of table.
-------
Page 3 of 3
Table 3-6 (Cont.)
a United States Environmental Protection Agency, Region 3, Risk-based Concentration Table, Fourth Quarter 1994, November 1994. Cancer risk = 1 x 10'6. Hazard
quotient = 0.1.
" Background data from sample locations AP-5734 and AP-6141, unless otherwise noted.
Background data provided by the Corps.
Key:
B = Blank concentration.
DDE = Dichlorodiphenyldichloroethene.
DRO = Diesel range organics.
J = Estimated quantity.
MCL = Maximum contaminant level.
jug/L = Micrograms per liter.
NA = Not applicable.
S = Secondary MCL.
TRPH = Total recoverable petroleum hydrocarbons.
U = Not detected.
— = Value not established.
-------
)\2£^"\ AP-6136
'AP-SRim /i<0> .
"AMi:ts^n
-<»..__ Shallow monitoring well
<^ Deep monitoring well
$> Organic compounds detected
above cleanup goals
* AP-6137 was formerly known as DH6534 (MW8)
ecology and environment, inc.
International Specialists in the Environment
U.S.ARMY CORPS OF ENGINEERS
ALASKA DISTRICT
ANCHORAGE, ALASKA
Figure 3-1
LANDFILL SOURCE AREA
CONTAMINANTS OF CONCERN
IN GROUNDWATER
OPERABLE UNIT 4
Fairbanks
Alaska
SIZE
A
JOB NO.
JT2901
FILE NO.
JT2CCGB2.CDR
DATE
96MAY03
PLATE
37
-------
02: JT\JT2901\OU4\JT2CCS_B.CDR
OAK AVENUE
WATER
TREATMENT PLANT
290B
(mg/kg or ppm)
POWER
PLANT
SETTLING
POND
AP-6160 (mg/kq or ppm)
FORMER
UNDERGROUND
STORAGE TANKS
AP-6164
(mg/kq or ppm)
ENCED
STORAGE
YARD
AP-6158
(mg/kg or ppm)
(mg/kg or ppm)
SURFACE
WATER.
COOLING POND
SCALE IN FEET
250
U.S.ARMY CORPS OF ENGINEERS
ALASKA DISTRICT
ANCHORAGE, ALASKA
ecology and environment, inc.
International Specialists in the Environment
Road
Railroad
Soil Sample Locations
Soil contaminants detected
above cleanup goals
Diesel Range Organics
Figure 3-2
COAL STORAGE YARD SOURCE AREA
CONTAMINANTS OF CONCERN IN SOIL
OPERABLE UNIT 4
Total Recoverable Petroleum
Hydrocarbons
mg/kg Milligram per kilogram
ppm Parts per million
JOB NO.
JT2901
FILE NO.
JT2CCS B.CDR
DATE
96MAY03
38
-------
02: JT\JT2901\JT2CCG2A.CDR
I I
f "65fo OAK AVENUE
i "A
CONTAMINANTS OF CONCERN
ORGANIC COMPOUNDS:
Trichloroethene - exceeds drinking water standards
Bis(2-ethylhexyl) phthalate - exceeds drinking water
standards
Benzene - exceeds drinking water standards and acceptable
risk range
SCALE IN FEET
0 250 500
PETROLEUM COMPOUNDS:
Total Recoverable Petroleum Hydrocarbons - exceeds
drinking water standards
Diesel Range Organics - exceeds drinking water standards
KEY*
4-
4>
t
Road
Railroad
Nested monitoring well
Shallow monitoring well
Intermediate monitoring well
Deep monitoring well
Drinking water supply well
A Deep drinking water supply well
A Water supply well
& Deep water supply well
O Microwells
^ .... „ _, u ,
-w- Monitoring well depth unknown
^
W Organic compounds detected
above cleanup goals
^ Petroleum compounds detected
ecology and environment, inc.
International Specialists in the Environment
U.S.ARMY CORPS OF ENGINEERS
ALASKA DISTRICT
ANCHORAGE, ALASKA
Figure 3-3
COAL STORAGE YARD SOURCE AREA
CONTAMINANTS OF CONCERN
IN GROUNDWATER
OPERABLE UNIT 4
Fairbanks
Alaska
SIZE
A
JOB NO.
JT2901
FILE NO.
JT2CCG2.CDR
DATE
96MAY03
PLATE
39
-------
4.0 SUMMARY OF SITE RISKS
The Baseline Human Health and Ecological Risk Assessment is one mechanism for determining the
need for taking action at the source areas and indicates the exposure pathways that need to be
addressed by remedial action. Risk assessments are performed using information on toxicity of
contaminants and assumptions regarding the extent to which people may be exposed to them. This
summary of the Baseline Human Health Risk Assessment for the source areas is divided into the five
following sections:
• Identification of contaminants of concern;
• Exposure assessment;
• Toxicity assessment;
• Risk characterization, which is an integration and summary of the
information gathered and analyzed in the preceding sections; and
• Analysis of the uncertainty involved in developing the Risk
Assessment.
The summary concludes with the results of the Ecological Risk Assessment conducted for the Landfill
and CSV source areas.
Human Health and Ecological Risk Assessments were conducted for OU-4 to determine potential risks
in the absence of remedial action. CERCLA guidance allows the Baseline Risk Assessment to reflect
the expected future use of a site. Scenarios involving future residential use of the Landfill and CSV
source areas were completed. However, these scenarios were determined to be inappropriate for soils
because industrial use is the reasonably anticipated future use based on the Post master plan and
historical use of both areas.
It was determined, because of site hydrologic conditions, that future residential risks identified in the
Baseline Human Health Risk Assessment are applicable to groundwater because an exposure pathway
for domestic water users currently exists. The NCP requires that groundwater be returned to its
beneficial uses whenever practicable. At these source areas, the beneficial use is domestic water
supply.
4.1 IDENTIFICATION OF CHEMICALS OF CONCERN (SCREENING ANALYSIS)
Selection of contaminants of concern, which are chemicals that potentially contribute to human health
risks at the source areas, was a two-step process. First, the maximum concentrations of contaminants
detected in on-site soil and water during 1993 investigations were compared to health-based screening
levels for drinking water, soil, and air in accordance with EPA, Region X, Supplemental Risk
Assessment Guidance. Region X recommends the use of EPA, Region 3, risk-based concentration
(RBC) values (April 20, 1994). These standards reflect residential exposure assumptions and 1 x 10"6
and 1 x 10~7 risks associated with groundwater and soil, respectively, or a hazard quotient of 0.1 for
all media. If risk-based screening numbers were not available, maximum groundwater concentrations
were compared to Safe Drinking Water Act MCLs. Secondly, inorganic chemicals were compared to
40
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naturally occurring background levels. If concentrations were found below established background
levels, they were eliminated from further evaluation. At the Landfill, 10 chemicals were identified as
contaminants of concern in groundwater, and nine contaminants were identified as contaminants of
concern in groundwater at the CSV. While soil contamination did not pose a direct threat to human
health, it does act as an ongoing source of contamination to groundwater. Table 4-1 presents the
contaminants of concern identified in each environmental medium evaluated.
4.2 EXPOSURE ASSESSMENT
The exposure assessment estimates the type and magnitude of exposures to the contaminants of
concern at the source areas. It considers the current and potential future uses of the site,
characterizes the potentially exposed populations, identifies the important exposure pathways, and
quantifies the intake of each contaminant of concern from each medium for each population at risk.
The Human Health Risk Assessment for OU-4 was divided into the Landfill, CSV and FTP source
areas. The FTPs were eliminated from further consideration because of the limited extent and type of
contamination.
4.2.1 Identification of Site Uses, Exposed Populations, and Exposure Pathways
4.2.1.1 Source Area Land Use Scenarios
The exposure assessment for the Landfill and CSV source areas considers land use scenarios to
evaluate exposed populations. The Baseline Human Health Risk Assessment evaluated future
residential land use of the source areas, which assumes that individuals would spend 30 years of their
time at the source. Although this use scenario is unlikely, it provides a conservative baseline to avoid
underestimation of risks. The industrial scenario assumes that the sources would continue to be used
for industrial purposes and that workers would spend 25 years of continuous employment at the site.
Tables 4-2 and 4-3 identify the potential exposure routes evaluated for the Human Health Risk
Assessment; however, it was determined that only the industrial scenario would be appropriate for
these source areas.
4.2.1.2 Exposed Populations and Pathways
An exposure pathway is the mechanism by which chemicals migrate from their source or point of
release to the population at risk. Four elements comprise a complete exposure pathway: 1) a source
of a chemical release; 2) movement of contaminants through environmental media; 3) a point of
potential human contact with a contaminated medium; and 4) entry into the body or exposure route.
The exposure pathways considered in the Baseline Risk Assessment varied depending on the land use
and on the population potentially exposed. The exposure assessment identified potential pathways for
contaminants of concern to reach the exposed population for each source area (see Tables 4-2 and
4-3). A "complete" exposure pathway must exist for a contaminant to pose a human health risk (i.e.,
the potential for a receptor to be exposed to a contaminant must exist).
4.2.1.3 Calculation of Exposure
EPA's Superfund guidance requires that the reasonable maximum exposure be used to calculate
41
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potential health impacts at Superfund sites. The reasonable maximum exposure, the highest exposure
that is reasonably expected to occur at the source areas, is calculated using conservative assumptions
in order to represent exposures that are reasonable and protective. The Baseline Human Health Risk
Assessment reasonable maximum exposure and average exposures were estimated for the residential
and industrial land use scenarios. Average exposures were calculated in order to represent exposures
of a more typical person.
To estimate exposure, data regarding the concentrations of contaminants of concern in the media of
concern at the source area (the exposure point concentrations) are combined with information about
the projected behaviors and characteristics of the people who potentially may be exposed to these
media (exposure parameters). These elements are described below.
a) Exposure Point Concentrations. Averages of defined sub-areas for
surface and subsurface soil and sediment sample results for each
source area were used as exposure point concentrations for the
reasonable maximum exposure and average exposure calculations.
Sources were divided into sub-areas for soils to reflect differences in
geographic locations and nature and extent of contamination.
Individual well data were used to determine groundwater risks.
Tables 4-4 and 4-5 contain the exposure point concentrations for
carcinogenic and noncarcinogenic contaminants of concern in surface
and subsurface soil, sediments, and gioundwater at the source areas.
b) Exposure Parameters. The parameters used to calculate the reasonable
maximum exposure include body weight, age, contact rate, frequency
of exposure, and exposure duration. Exposure parameters were
obtained from EPA, Region X, risk assessment guidance (EPA,
Region X Supplemental Risk Assessment Guidance for Superfund [EPA
1991]). The default exposure factors were modified to reflect site-
specific climatological and other factors at Fort Wainwright. Site-
specific exposure assumptions were made for soil contact, including
ingestion, dermal contact, and inhaling dust, based on snow cover half
the year.
For all of the media, exposures were estimated assuming long-term exposures to source area
contaminants.
4.3 TOXICITY ASSESSMENT
The Baseline Human Health Evaluation provides toxicity information for the chemicals of concern.
Generally, cancer risks are calculated using toxicity factors known as "slope factors," while noncancer
risks rely on reference doses.
EPA has developed slope factors for estimating lifetime cancer risks associated with exposure to
potential carcinogens. Slope factors are expressed in units of (mg/kg-day"*) and are multiplied by the
estimated intake of a potential carcinogen, in mg/kg-day, to provide an upper-bound estimate of the
excess lifetime cancer risk associated with exposure at that intake level. The term "upper-bound"
reflects the conservative estimate of the risks calculated from the slope factor. Use of this approach
42
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makes it highly unlikely that the actual cancer risk would be underestimated. Slope factors are
derived from the results of human epidemiological studies or chronic animal bioassays to which
mathematical extrapolations from high to low dose and from animal to human dose have been applied.
Reference doses have been developed to indicate the potential for adverse health effects from
ingestion of potential contaminants of concern that exhibit noncancer effects, such as damage to organ
systems (e.g., the nervous system, blood-forming system, etc.). They are also expressed in units of
mg/kg-day. Reference doses are estimates within an order of magnitude of lifetime daily exposure
levels for people, including sensitive individuals, who are likely to be without risk of adverse effect.
Estimates of intakes of contaminants of concern from environmental media (e.g., the amount of a
contaminant of concern ingested from contaminated drinking water) can be compared to the reference
dose. Reference doses are derived from human epidemiological studies or from animal studies to
which uncertainty factors have been applied.
The toxicity factors were drawn from the Integrated Risk Information System or, if no Integrated Risk
Information System values were available, from the Health Effects Assessment Summary Tables. For
chemicals that do not have toxicity values available at this time, other criteria, such as MCLs
promulgated under the Safe Drinking Water Act, were used to assess potential hazards.
4.4 RISK CHARACTERIZATION
The purpose of the risk characterization is to integrate the results of the exposure assessment and the
toxicity assessment to estimate risk to humans from exposure to site contaminants. Risks were
calculated for carcinogenic (cancer-causing) and noncarcinogenic (toxic) effects based on the
reasonable maximum exposure (see exposure assessment discussion). To estimate cancer risk, the
slope factor is multiplied by the exposure expected for that chemical to provide an upper-bound
estimate of the excess lifetime cancer risk. This estimate is the incremental probability of an
individual developing cancer over a lifetime as a result of exposure to cancer-causing chemicals at a
source area. EPA considers that excess lifetime cancer risks between 1 in 1 million (1 x 10"6) and 1 in
10,000 (1 x 10"4) are within the generally acceptable range; risks greater than 1 in 10,000 usually
suggest the need to take action at a site.
In defining effects from exposure to noncancer-causing contaminants, EPA considers acceptable
exposure levels as those that do not adversely affect humans over their expected lifetime with a built-
in margin of safety. Potential concern for noncarcinogenic effects of a single contaminant in a single
medium is expressed as a hazard quotient, which is the ratio of the estimated exposure from a site's
contaminant to that contaminant's reference dose. If this ratio, called a "hazard quotient," is less than
1, then adverse noncancer health effects are not likely to occur. Hazard quotients for individual
contaminants of concern are summed to yield a hazard index for the sub-area. The potential excess
lifetime cancer risks and hazard indices described in this summary were calculated using reasonable
maximum exposure assumptions. Table 4-6 presents cancer and noncancer risks for groundwater for
the Landfill and CSV.
The potential human health risks at Fort Wainwright were characterized for groundwater by
estimating risks on a well-specific basis. Soils were evaluated on a sub-area basis to allow for
differences in geographic location as well as nature and extent of contamination. This approach
retains information on the geographic distribution of risk throughout the source areas. The well and
sub-area-specific risk assessment approach were used to distinguish specific Landfill and CSY areas
43
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that exceed risk-based levels. Excess lifetime cancer risks and hazard indices for current and future
scenarios for groundwater are summarized in Figures 4-1 through 4-4. Excess lifetime cancer risks
for current and future scenarios for soil, sediment, and air contamination are below or within the 1-
in-10,000 to 1-in-l million risk range.
Under current land use conditions, the estimates of carcinogenic and noncarcinogenic effects for the
OU-4 source areas fell within or below the acceptable risk range for the CERCLA sites. The future
land use for both the CSV and the Landfill was determined to be industrial. However, a residential
scenario for groundwater use is considered appropriate and representative of risk to current
downgradient users, given Landfill and CSV hydrological conditions. When considering groundwater
as a source of domestic water, several contaminants were detected in groundwater at concentrations
above EPA's acceptable risk range for both source areas. These risk drivers include manganese;
antimony; arsenic; benzene; bis(2-ethylhexyl)phthalate; dioxins and furans; and 1,1,2,2-
tetrachloroethane. Note, however, that the manganese, antimony, and arsenic concentrations detected
at OU-4 reflect background concentrations in this mineralogically rich area. Dioxin and furan
concentrations are below drinking water MCLs. The presence of benzene and bis(2-
ethylhexyl)phthalate remains a risk driver for both source areas, and 1,1,2,2-tetrachloroethane is a
risk driver at the Landfill.
Risks associated with TCE were not calculated for either source area, although this contamination is
present in groundwater at both locations. This is because the cancer slope factors for TCE have been
withdrawn from the toxicological data bases, Integrated Risk Information System, and Health Effects
Assessment Summary Tables. In the absence of an accepted risk value, the MCL is used to establish
the need for action for TCE at the Landfill and CSV.
4.4.1 Landfill Source Area
Excess lifetime cancer risks associated with potential downgradient drinking water use of Landfill
groundwater ranged from 2x 10"7 to 3 x 10~3, depending on which well is used. The contaminants of
concern that are attributable to Landfill activities and that exceed the acceptable risk range are
1,1,2,2-tetrachloroethane and bis(2-ethylhexyl)phthalate. Arsenic was the only contaminant in one
downgradient well found at concentrations exceeding 1 x 10"4. Hazard indices associated with future
residential groundwater use ranged from 0.3 to 39, with manganese being solely responsible for all
hazard indices over 1. Arsenic and manganese concentrations are contaminants of concern naturally
occurring at these concentrations detected and not associated with Landfill activities.
A semi-quantitative evaluation of TCE risks was completed by comparing contaminant concentrations
to Region 3 risk-based concentrations. The evaluation indicated that TCE would have a relatively
minor impact on total risk estimates at the Landfill.
EPA's screening level of 1,000 mg/kg for lead in soil at industrial sites was exceeded at one location
where a small petroleum spill apparently occurred at the Landfill. Consequently, the soil lead
concentrations detected at the Landfill (up to 2,480 mg/kg) could elicit adverse health effects if
children were to be exposed through inhalation or ingestion of the soils. However, this small location
subsequently was permanently covered with approximately 8 feet of building debris and landfill cover
material during a landfill stabilization effort conducted in summer 1995. Therefore, this small source
no longer poses a risk from dermal contact.
44
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4.4.2 Coal Storage Yard Source Area
No risks greater than 1 x IQr6 or a hazard quotient of 1 were associated with current or future use of
CSY soils. Risks associated with potential downgradient drinking water users do exceed an excess
lifetime cancer risk of 1 x 10"4. The primary contaminants of concern are benzene and dioxins/furans.
However, the dioxin/furan compounds do not exceed state and federal drinking water standards.
Hazard indices associated with downgradient residential groundwater use ranged from 0.001 to 7; the
principal contaminants of concern were antimony and manganese. Both of these metals are
considered to be naturally occurring.
A semi-quantitative evaluation of TCE risks was completed by comparing contaminant concentrations
to Region 3 RBCs. The evaluation indicated that the exclusion of trichlorethene may serve to
underestimate potential risks at one well at the CSY. TCE at the CSY will be treated through the
selected remedial alternative.
4.5 MAJOR UNCERTAINTIES
Uncertainty is associated with every step of the risk assessment process. The principal uncertainties
associated with the OU-4 risk assessment process that could result in overly conservative risk
evaluations are summarized below:
• Derivation of future surface soil concentrations from subsurface soil
data. The assumption that subsurface soil would be disturbed and
mixed with the present surface soil layer is an extremely conservative
approach.
Uncertainties that may serve to underestimate site-related risk and exposures include:
• Sampling of CSY environmental media may not have occurred in the
most contaminated areas because of sampling constraints associated
with operational activities;
• Qualified data from the analysis of dioxin/furan samples for the CSY
soils resulted in exclusion of these data from the quantitative Risk
Assessment. Consequently, risks associated with these analytes may
be underestimated in this Baseline Human Health Risk Assessment;
and
• High sample quantitation limits. Several analytes consistently
exhibited sample quantitation limits greater than EPA's Region 3
RBCs, reflecting sample matrix interference, sample dilution, or
inadequate detection limits for analytes not anticipated to be
contaminants of concern at OU-4.
4.6 ECOLOGICAL RISKS
An Ecological Risk Assessment addresses the impacts and potential risks posed by contaminants to
natural habitats, including plants and animals, in the absence of remedial action. The three main
45
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phases of the Ecological Risk Assessment are problem formulation, analysis, and risk
characterization.
The following section presents a brief discussion of the Ecological Risk Assessment steps described
above.
4.6.1 Problem Formulation
To narrow the scope and to focus the Ecological Risk Assessment on the most important aspects of
OU-4, many steps were performed. A physical site description of the ecological features of interest at
the Landfill and CSV was prepared, and previous ecological investigations, including wildlife
inventories and Environmental Impact Statements, were reviewed. A description of the regional and
local ecology was completed and threatened, endangered, sensitive, or rare species were identified.
Chemicals of potential ecological concern were identified by reviewing the OU-4 analytical data base
with regard to data quality, spatial representation and adequacy for an Ecological Risk Assessment;
frequency with which analytes are detected in environmental media; comparison to background
concentrations; and comparison to ecological risk-based criteria for sediment and surface water.
Next, pathways of contaminant migration and exposure were identified by evaluating sources of
contaminants and the mechanisms by which they may be transported to media of ecological concern,
plants, and animals.
Potential ecological effects are summarized by reviewing the toxicological literature. These
summaries present a review of the known toxicological effects of the chemicals of potential ecological
concern on wildlife species.
Two types of ecological endpoints are considered in the Ecological Risk Assessment: assessment and
measurement endpoints:
• Assessment endpoints are qualitative or quantitative expressions of the
environmental values to be protected at OU-4 and are selected by
considering species that play important roles in community structure
or function; species of societal significance or concern; species of
concern to federal and state agencies; diet, habitat preference, and
behaviors that predispose the species to chemicals of potential
ecological concern exposure; amenability of the selected species to
measurement or prediction of effects; and species that may be
particularly sensitive to the chemicals of potential ecological concern
identified at OU-4; and
• Measurement endpoints include the species and communities used to
quantify the potential ecological impacts posed by OU-4 chemicals of
potential ecological concern. Representative measurement species are
selected based on the relative abundance of each species and
establishing functional groups based on trophic level and preferred
habitat. Representative indicator species are then selected based on
the potential for exposure and the availability of toxicological data.
The following measurement species and communities were selected for
46
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evaluation at OU-4: aquatic macroinvertebrates, terrestrial vegetation,
soil macroinvertebrates (e.g., earthworms), masked shrews, mallards,
American robins, and American kestrels.
The refined conceptual ecological exposure models for OU-4 can be summarized by the following
working hypotheses:
• Potential ecological risks may result from exposure of terrestrial
wildlife and vegetation to chemicals of potential ecological concern
found in the surface soils of OU-4;
• Potential ecological risks may result from exposure of waterfowl to
the chemicals of potential ecological concern found in the Landfill
wetlands and the CSY cooling pond; and
• Chemicals of potential ecological concern in Landfill wetlands, the
CSY cooling pond, and Chena River surface water and sediment may
affect the populations of aquatic and benthic macroinvertebrates that
inhabit them.
4.6.2 Analysis
The analysis phase of the Ecological Risk Assessment evaluates receptor exposure to chemicals of
potential ecological concern and the potential adverse effects of that exposure. Analysis of exposure
and effects is based on the ecological endpoints and refined conceptual site model derived during the
problem formulation phase. Analysis comprises two principal components:
• Exposure assessment, in which exposure point concentrations and
chemicals of potential ecological concern intakes for the measurement
species are calculated; and
• Ecological effects assessment, in which toxicity benchmark values are
derived from the literature and lexicological data bases, and
uncertainty factors are selected and applied to the toxicity benchmark
values to yield toxicity reference values. The uncertainty factors are
used to compensate for applying data derived from laboratory or
domestic animal studies to free-ranging wildlife (for which little
empirical data are available).
4.6.3 Risk Characterization
Risk characterization involves two major components: risk estimation and risk description.
4.6.3.1 Risk Estimation
Risk estimation involves calculating hazard quotients to assess potential ecological risks to measure-
ment species and communities. This method involves comparing calculated exposure doses or media
concentrations with toxicity reference values and/or experimentally derived risk-based concentrations.
47
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Ecological effects are quantified by calculating the ratio between a chemical of potential ecological
concern's estimated intake or concentration and its corresponding toxicity reference value (i.e., the
intake level or concentration at which no adverse ecological effects are expected to occur). If this
ratio (i.e., the hazard quotient) exceeds 1, then adverse ecological effects may be expected for the
chemical of potential ecological concern. The hazard quotients described in this summary were
calculated using conservative reasonable maximum exposure assumptions.
The hazard quotients for each exposure pathway (e.g., soil ingestion and surface water ingestion) may
be summed for each chemical of potential ecological concern to establish contaminant-specific hazard
indices for each measurement species. The hazard indices provide a species- and contaminant-specific
characterization of the potential ecological risks across all of the assessed exposure pathways.
Finally, the hazard indices can be added across contaminants that have similar effects.
4.6.3.2 Risk Description
Risk description involves summarizing the ecological significance of the potential risks and presenting
the uncertainties associated with the Ecological Risk Assessment.
The results of the Ecological Risk Assessment for OU-4 indicate a potential for effects to small
mammals (shrews, voles, etc.) at the Landfill, reflecting ecologically significant concentrations of
copper, and at the CSY based on concentrations of copper, cadmium, and selenium. These risks are
associated with ingestion of soil and earthworms. These contaminants do not appear to be associated
with historical source area activities and are consistent with regional background concentrations.
Barium poses potential risks to passerine birds (robins, sparrows, etc.) at the Landfill, and barium and
copper pose a risk to passerine birds at the CSY through ingestion of soil and earthworms. However,
these locations represent a relatively small habitat area. Additionally, both the Landfill and CSY are
industrial areas with a significant amount of heavy equipment and human activity. The habitat area in
these locations has been significantly altered from the surrounding land. Specific species surveys and
traps were not used for the Landfill and CSY. The actual number of animals that could be affected
by these chemicals could be very low. No significant effects were predicted for waterfowl (mallards),
raptors (kestrels), or terrestrial vegetation.
At the Landfill wetlands and the CSY cooling pond, benthic (sediment-dwelling) invertebrates may be
slightly impacted by metals or dichlorophenyltrichloroethane (also known as "DDT") and its
metabolites present in the sediments. These concentrations are consistent with Postwide levels and
most likely represent residues associated with historical aerial spraying of the Fairbanks area for
mosquito control. These concentrations do not appear to be associated with a chemical release
associated with Landfill or CSY activities. No potential effects were predicted for aquatic (surface
water-dwelling) species. There do not appear to be unacceptable potential ecological risks associated
with the Landfill or CSY source areas. However, capping of the Landfill will minimize surface
exposure to passerine birds. Remediation activities at the CSY are not expected to change inorganic
chemical concentrations.
The Ecological Risk Assessment is subject to uncertainties because virtually every step in the risk
assessment process involves assumptions involving professional judgment. Principal uncertainties
associated with the OU-4 Ecological Risk Assessment include the following:
• A limited number of samples was collected from the source areas, and
48
-------
the samples were biased toward areas of "expected" soil contamina-
tion. This is likely to result in an overestimation of potential risks to
the OU-4 ecological receptors;
Exposure parameters for all measurement species were selected based
on professional judgment. The amount of food consumed on a daily
basis, the different types of food consumed, and the percentage of the
whole diet that each food item contributes were estimated based on a
combination of scientific literature and limited field observation
information. In addition, the amount of time spent foraging on site is
estimated using similar information. Without extensive site-specific
field data, it is unclear whether potential risks are underestimated or
overestimated using the selected exposure parameters;
Ingestion rates for all measurement species were converted from a
wet- to a dry-weight basis for use in the ecological exposure model.
To convert these ingestion rates, assumptions regarding moisture
content of food items for measurement were made. It is unclear
whether these assumptions overestimate or underestimate potential
risks to undeveloped Landfill species;
For the shrew, mallard, and robin, exposure through incidental
ingestion of surface soil accounted for a significant portion of the
estimated risk for these species. Species-specific soil ingestion rates
were unavailable for the shrew and the robin. It was assumed that
these two receptors ingested soil at 10.4% of their daily dietary intake
while foraging. This assumption is likely to result in an overestima-
tion of potential risks from soil ingestion for these species;
The modeling approach used to estimate site-related chemical of
potential ecological concern concentrations in vegetation and shrew
and robin tissue is a major source of uncertainty. Plant uptake and
small mammal and bird bioaccumulation factors were derived from
data reported in the scientific literature and likely are correlated with
site-specific variables such as soil type, soil chemistry, and wildlife
species. It is unclear whether the application of these literature-
derived values overestimate or underestimate potential risks to
measurement communities;
Frequently, toxicity and exposure data from literature sources were
not specific to the target receptors; therefore, extrapolation of the data
to the species of concern was necessary. Differences in toxic response
between species are well-documented, even among species of the same
genus. Because toxicity data were unavailable for the shrew, mallard,
and robin, values were derived from laboratory species (i.e., rat,
mouse, Japanese quail, California quail, bobwhite quail, chicken,
turkey, mallard, ringneck pheasant, and American kestrel). The
differences in species-specific toxicity were addressed in this
49
-------
assessment using uncertainty factors, which may not accurately predict
inter- and intra-species differences in toxic response. Therefore,
actual risk may be overestimated or underestimated;
• Uncertainty factors obtained from available literature and based on
best professional judgment were applied to normalize lexicological
data to chronic no observed effect levels. Considerable uncertainty is
associated with their application; however, the desired result is a
conservative estimate of the no observed effect level, which should
result in a conservative estimate of any potential risks;
• Toxicity values were not found for several of the chemicals of
potential ecological concern, which resulted in an underestimation of
potential risks to OU-4 species;
• Most of the available toxicity values were determined with laboratory
animals under laboratory conditions. Such studies may not accurately
reflect the effects of similar doses on free-ranging wildlife;
• Toxicity values determined with indirect effect measures (such as
increased body weight) may not represent other significant indirect
effects (such as behavioral changes) that may be realized in wild
populations; and
• Suitable phytotoxicity and soil macroinvertebrate information was very
limited. In cases where data were available, the lowest reported a
chemical of potential ecological concern concentration that elicited an
adverse effect was selected. However, this value was specific for the
species tested and may not be representative of species found on
OU-4.
The approach described in this Ecological Risk Assessment used realistic assumptions wherever
possible; reasonable and conservative assumptions were used when empirical data were unavailable.
As a consequence, potential ecological risks to OU-4 species are more likely to be overestimated than
underestimated.
50
-------
Page 1 of 1
Table 4-1
CHEMICALS OF CONCERN
FROM HUMAN HEALTH RISK ASSESSMENT
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Analyte
Source Area
Landfill
Coal Storage Yard
INORGANICS
Antimony
Arsenic
Beryllium
Lead
Manganese
—
Soilb, GW
—
Soil
GW
GWa
—
Soil
—
GW
ORGANICS
1 , 1 ,2,2-Tetrachloroethane
1 , 1 ,2-Trichloroethane
1 ,2-Dichloroethane
2,3,7,8-TCDD
4,4'-DDE
Benzene
bis(2-ethylhexyl)phthalate
Bromodichloromethane
Chloroform
Dieldrin
Heptachlor
Heptachlor epoxide
Vinyl chloride
GW
GW
GW
—
—
GW
GW, Soil
GW
GW
—
—
—
GW
—
—
—
GW
GW
GW
GW
—
—
GW
GW
GW
—
a COC in groundwater.
COC in surface soil, subsurface soil, and ash (Landfill only).
Key:
— = Not identified as a COC in environmental media at this source area.
COC = Chemical of concern.
DDE = Dichlorodiphenyldichloroethene.
GW = Groundwater.
TCDD = Tetrachlorodibenzo-/>-dioxin.
51
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Page 1 of 1
Table 4-2
POTENTIAL EXPOSURE ROUTES
LANDFILL SOURCE AREA
FROM HUMAN HEALTH RISK ASSESSMENT
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Exposure Medium and Route
Commercial and
Industrial
Population8
Site Visitor and
Recreational
Population9
Potential
Impacted Supply
Aquifer Scenario
Groundwater
Ingestion
Dermal contact
—
—
X
X
X
X
Air
Inhalation of indoor vaporsb
Inhalation of fugitive dust (soil)0
Inhalation of fugitive dust (ash)d
—
X
X
—
X
X
X
—
—
Surface Soil
Ingestion
X
X
—
Subsurface Soil6
Ingestion
X (future)
X (future)
—
Ash
Ingestion
Dermal contact
X
X
X
X
—
—
a Evaluated in current and future land use scenarios, unless otherwise noted.
Indoor vapors originate from groundwater.
^ Fugitive dust originates from soil (surface soil only for current scenarios and surface and subsurface soil
combined for future scenarios).
j '
Fugitive dust originates from ash.
Subsurface soil is assumed to be mixed with surface soil for future scenarios. Therefore, the subsurface soil data
will be combined with the surface soil data for future scenarios.
Key:
X =
Exposure of this population through this route is not likely to occur.
Exposure of this population through this route will be evaluated in the baseline human health risk
assessment.
52
-------
Page 1 of 1
Table 4-3
POTENTIAL EXPOSURE ROUTES
COAL STORAGE YARD SOURCE AREA
FROM HUMAN HEALTH RISK ASSESSMENT
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Exposure Medium and Route
Commercial and
Industrial
Population3
Site Visitor and
Recreational
Population8
Potential
Impacted Supply
Aquifer Scenario
Groundwater
Ingestion
Dermal contact
—
_
X
X
X
X
Air
Inhalation of indoor vaporsb
Inhalation of fugitive dust (soil)0
—
X
X
X (future)
X
—
Surface Soild
Ingestion
X
X (future)
_
Subsurface Soil6
Ingestion
X (future)
X (future)
—
a Evaluated in current and future land use scenarios, unless otherwise noted.
Indoor vapors originate from groundwater.
Fugitive dust originates from soil (surface soil only for current scenarios and surface and subsur-
face soil combined for future scenarios).
Dermal contact with soil was not evaluated at the Coal Storage Yard because insufficient dermal absorption
data are available for the contaminants of potential concern associated with soil.
Subsurface soil is assumed to be mixed with surface soil for future scenarios.
Key:
— = Exposure of this population through this route is not likely to occur.
X = Exposure of this population through this route will be evaluated in the baseline human
health risk assessment.
53
-------
Page 1 of 5
.£>•
Table 4-4
EXPOSURE POINT CONCENTRATIONS FOR SOILS
CURRENT AND FUTURE EXPOSURE SCENARIOS
FROM HUMAN HEALTH RISK ASSESSMENT
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Source Area/Sub-Area
Soil Type
COPC
EPC
(mg/kg)
No. of Samples
Analyzed/Detected
EPC Derivation
CURRENT EXPOSURE SCENARIOS
Landfill/Sub-Area A—
Drainage SE of landfill, north of River
Road.
Landfill/Sub-Area B—
Drainage SE of landfill, south of River
Road.
Landfill/Sub-Area C—
Hot spot near off-road vehicle recreation
area.
Landfill/Sub-Area D—
Drainage SW of landfill, south of River
Road.
Surface
Surface
Surface
Surface
Aluminum
Dieldrin
Manganese
Vanadium
DDT
Arsenic
Manganese
Manganese
DDE
DDT
Manganese
38,000
0.099
426
56
0.247
21
530
343
0.191
0.692
515
8/8
8/4
8/8
8/8
5/4
5/5
5/5
1/1
6/1
6/1
6/6
Maximum detected concentration
Maximum detected concentration
Maximum detected concentration
Maximum detected concentration
Maximum detected concentration
Maximum detected concentration
Maximum detected concentration
Only detected concentration
Maximum detected concentration
Maximum detected concentration
Maximum detected concentration
Key at end of table.
-------
Page 2 of 5
t_n
01
Table 4-4
EXPOSURE POINT CONCENTRATIONS FOR SOILS
CURRENT AND FUTURE EXPOSURE SCENARIOS
FROM HUMAN HEALTH RISK ASSESSMENT
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Source Area/Sub-Area
LandfilVSub-Area E—
SS-29 - Hot spot west of landfill.
Coal Storage Yard/AP-6159
Coal Storage Yard/AP-6162
Soil Type
Surface
Surface
Surface
COPC
Barium
Bis(2-ethylhexyl)pht-
halate
Cadmium
Chromium
Lead
Aluminum
Barium
Beryllium
Manganese
Selenium
Vanadium
Beryllium
Cadmium
Manganese
EPC
(mg/kg)
559
43.5
11
42
2,480
44,100
2,630
2.2
572
52
112
0.52
54
321
No. of Samples
Analyzed/Detected
1/1
1/1
1/1
1/1
1/1
1/1
1/1
1/1
1/1
1/1
1/1
1/1
1/1
1/1
EPC Derivation
Only detected concentration
Only detected concentration
Only detected concentration
Only detected concentration
Only detected concentration
Maximum detected concentration
Maximum detected concentration
Maximum detected concentration
Maximum detected concentration
Maximum detected concentration
Maximum detected concentration
Maximum detected concentration
Maximum detected concentration
Maximum detected concentration
Key at end of table.
-------
Page 3 of 5
ui
ON
Table 4-4
EXPOSURE POINT CONCENTRATIONS FOR SOILS
CURRENT AND FUTURE EXPOSURE SCENARIOS
FROM HUMAN HEALTH RISK ASSESSMENT
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Source Area/Sub-Area
Coal Storage Yard/Sub-Area F—
East of cooling pond, south of railroad
tracks.
FUTURE EXPOSURE SCENARIOS
Landfill/Sub-Area A—
Drainage SE of landfill, north of River
Road.
Landfill/Sub-Area B—
Drainage SE of landfill, south of River
Road.
Landfill/Sub-Area C—
Hot spot near off-road vehicle
recreation area.
Landfill/Sub-Area D—
Drainage SW of landfill, south of River
Road.
Soil Type
Surface
Surface and
Subsurface
Surface
Surface
Surface and
Subsurface
COPC
Beryllium
Aluminum
Dieldrin
Manganese
Vanadium
DDT
Arsenic
Manganese
Manganese
DDE
DDT
Manganese
EPC
(mg/kg)
0.475
21,361
0.025
338
41.3
0.247
21
530
343
0.191
0.692
515
No. of Samples
Analyzed/Detected
2/2
EPC Derivation
Maximum detected concentration
11/11
1/41
11/11
11/11
5/4
5/5
5/5
1/1
7/1
7/1
7/7
UCL - log-normal distribution
UCL - Helsel's method
UCL - normal distribution
UCL - normal distribution
Maximum detected concentration
Maximum detected concentration
Maximum detected concentration
Only detected concentration
Maximum detected concentration
Maximum detected concentration
Maximum detected concentration
Key at end of table.
-------
Page 4 of 5
ui
Table 4-4
EXPOSURE POINT CONCENTRATIONS FOR SOILS
CURRENT AND FUTURE EXPOSURE SCENARIOS
FROM HUMAN HEALTH RISK ASSESSMENT
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Source Area/Sub-Area
Landfill/Sub-Area E—
SS-29 - Hot spot west of landfill.
Coal Storage Yard/AP-6159
Coal Storage Yard/AP-6162
Soil Type
Surface
Surface and
Subsurface
Surface and
Subsurface
COPC
Barium
bis(2-ethylhexyl)pht-
halate
Cadmium
Chromium
Lead
Aluminum
Barium
Beryllium
Manganese
Selenium
Vanadium
Beryllium
Cadmium
Manganese
EPC
(mg/kg)
559
43.5
11
42
2,480
44,100
2,630
1.7
493
52
112
0.47
54
285
No. of Samples
Analyzed/Detected
1/1
1/1
1/1
1/1
1/1
2/2
2/2
2/2
2/2
2/1
2/2
2/2
2/1
2/2
EPC Derivation
Only detected concentration
Only detected concentration
Only detected concentration
Only detected concentration
Only detected concentration
Maximum detected concentration
Maximum detected concentration
Maximum detected concentrations
Maximum detected concentrations
Maximum detected concentration
Maximum detected concentration
Maximum detected concentration
Maximum detected concentration
Maximum detected concentration
Key at end of table.
-------
Page 5 of 5
Table 4-4
EXPOSURE POINT CONCENTRATIONS FOR SOILS
CURRENT AND FUTURE EXPOSURE SCENARIOS
FROM HUMAN HEALTH RISK ASSESSMENT
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Source Area/Sub-Area
Coal Storage Yard/Sub-Area F —
East of cooling pond, south of
railroad tracks.
Soil Type
Surface and
Subsurface
COPC
Beryllium
Manganese
EPC
(mg/kg)
0.44
301
No. of Samples
Analyzed/Detected
10/10
10/10
EPC Derivation
UCL - normal distribution
UCL - normal distribution
Ul
00
Key:
COPC = Contaminant of potential concern.
DDE = Dichlorodiphenyldichloroethylene.
DDT = Dichlorodiphenyltrichloroethane.
EPC = Exposure point concentration.
mg/kg = Milligrams per kilogram.
UCL = Upper confidence limit on the mean.
-------
Pa:
if 5
Table 4-5
EXPOSURE POINT CONCENTRATIONS IN GROUNDWATER (^g/L)
FROM HUMAN HEALTH RISK ASSESSMENT
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Analyte
Antimony
Manganese
1 ,1 ,2,2-Tetrachloroethane
1 , 1 ,2-Trichloroelhane
1 ,2-Dichlorocthane
2,3,7,8-TCDD
4,4'-DDE
Benzene
bis(2-ethylhexyl)phthalate
Bromodichloromethane
Chloroform
cis-1 ,2-DichIoroethene
Dieldrin
Heptachlor
Heptachlor Epoxide
Methylene Chloride
trans-1 ,2-Dichloroethene
Trichlorofluoromethane
Vinyl Chloride
Coal Storage Yard Wells
AP-5508
26
< BKGD
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
AP-S509
ND
< BKGD
ND
ND
ND
1 .32E-05
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
AP-5510
28
< BKGD
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
AP-S511
32
920
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
AP-5736
20.25
< BKGD
ND
ND
ND
6.4E-08
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
AP-6142
ND
< BKGD
ND
ND
ND
ND
ND
ND
110
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
AP-6143
ND
< BKGD
ND
ND
ND
ND
ND
ND
12
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
MW-1D
ND
ND
ND
ND
ND
ND
ND
ND
2
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
MW-2S
ND
ND
ND
ND
ND
ND
0.09
ND
ND
ND
ND
ND
0.03
0.04
ND
ND
ND
ND
ND
Key at end of table.
-------
ag^Kf 5
Table 4-5
EXPOSURE POINT CONCENTRATIONS IN GROUNDWATER (/ig/L)
FROM HUMAN HEALTH RISK ASSESSMENT
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Analyte
Antimony
Manganese
1 ,1 ,2,2-Tetrachloroe thane
1 , 1 ,2-Trichloroethane
1 ,2-DichIoroethane
2,3,7,8-TCDD
4,4'-DDE
Benzene
bis(2-ethylhexyl)phthalate
Bromodichloromethane
Chloroform
cis-1 ,2-Dichloroethene
Dieldrin
Heptachlor
Heptachlor Epoxide
Methylene Chloride
trans- 1 ,2-Dichloroethene
Trichlorofluoronielhane
Vinyl Chloride
Coal Storage Yard Wells
MW-2D
ND
ND
ND
ND
ND
ND
ND
ND
13
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
WS-099
37
< BKGD
ND
ND
ND
ND
ND
ND
R
ND
ND
ND
0.01
ND
0.01
ND
ND
ND
ND
WS-119
ND
< BKGD
ND
ND
ND
4.8E-06
ND
ND
ND
ND
ND
ND
0.012
ND
0.013
ND
ND
ND
ND
3559-A
ND
< BKGD
ND
ND
ND
ND
ND
ND
6
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
3595-01
ND
2,000*
ND
ND
ND
4.5E-08
ND
ND
ND
ND
ND
ND
ND
ND
ND
4.3
ND
ND
ND
3595-02
ND
1,100"
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
0.08
ND
4
ND
ND
ND
3595-03
ND
1,909"
ND
ND
ND
ND
ND
2.8
ND
ND
ND
2.3
ND
ND
ND
ND
ND
84.5
ND
Key at end of table.
-------
PageTof 5
Table 4-5
EXPOSURE POINT CONCENTRATIONS IN GROUNDWATER (/ig/L)
FROM HUMAN HEALTH RISK ASSESSMENT
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Analyte
Arsenic
Barium
Fluoride
Manganese
1 , 1 ,2,2-Tetrachloroethane
1 , 1 ,2-Trichioroethane
1 ,2-Dichloroethane
2,3,7,8-TCDD
4,4'-DDE
Benzene
bis(2-ethylhexyl)phthalatc
Bromodichloromethane
Chloroform
cis-1 ,2-Dichloroethene
Dieldrin
Heptachlor
Heptachlor Epoxide
Methylene Chloride
trans- 1 ,2-Dichloroethene
Trichlorofluoromethane
Vinyl Chloride
Landfill Wells
AP-5585
< BKGD
< BKGD
ND
1,300"
ND
ND
ND
NA
ND
ND
ND
ND
ND
ND
R
R
R
2
ND
ND
ND
AP-5588
< BKGD
370
ND
2,200a
1,133
9.2
4.1
NA
ND
4.1
ND
ND
ND
143.3
R
R
R
ND
48.3
ND
1.3
AP-5589
ND
550
< BKGD
1,600"
6.1
ND
5.1
NA
ND
5.4
88
ND
ND
14.5
ND
ND
ND
5.7
3.8
ND
1.4
AP-5591
< BKGD
< BKGD
< BKGD
l,500a
ND
ND
ND
NA
ND
1.7
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
AP-S593
ND
< BKGD
ND
770"
ND
ND
ND
NA
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
AP-5594
ND
< BKGD
ND
< BKGD"
ND
ND
ND
NA
ND
ND
ND
ND
ND
ND
ND
ND
ND
R
ND
ND
ND
AP-6133
ND
< BKGD
< BKGD
< BKGD"
ND
ND
ND
NA
ND
ND
48
1.7
20
ND
ND
ND
ND
ND
ND
ND
ND
AP-6134
ND
R
< BKGD
R
ND
ND
ND
NA
ND
ND
69
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
AP-6136
ND
No Data
< BKGD
810"
ND
ND
ND
NA
ND
2.9
620
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Key at end of table.
-------
rO
Table 4-5
EXPOSURE POINT CONCENTRATIONS IN GROUNDWATER Gtg/L)
FROM HUMAN HEALTH RISK ASSESSMENT
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Analyte
Arsenic
Barium
Fluoride
Manganese
1 . 1 ,2,2-Tetrachloroethane
1 , 1 ,2-TrichIoroethane
1 ,2-Dichloroethane
2,3,7,8-TCDD
4,4'-DDE
Benzene
bis(2-ethylhexyl)phthalate
Bromodichloromethane
Chloroform
cis-1 ,2-Dichloroethene
Dieldrin
Heptachlor
Heptachlor Epoxide
Methylene Chloride
trans-1 ,2-Dichloroethene
Trichlorofluoromethane
Vinyl Chloride
Landfill Wells
AP-6137
< BKGD
< BKGD
< BKGD
l,400a
6.4
ND
ND
NA
ND
2.5
15
ND
1.7
8.8
ND
ND
ND
4.6
4.8
ND
ND
AP-6138
ND
No Data
980
< BKGD8
ND
ND
ND
NA
ND
2.7
73
2
17.2
ND
ND
ND
ND
ND
ND
ND
ND
AP-6139
74
360
< BKGD
5,800"
ND
ND
ND
NA
R
ND
ND
ND
ND
ND
R
ND
R
2.5
ND
ND
ND
FWLF-02
ND
< BKGD
ND
< BKGD8
ND
ND
ND
NA
ND
ND
ND
ND
ND
ND
ND
ND
ND
R
ND
ND
ND
FWLF-03
ND
< BKGD
< BKGD
840"
ND
ND
ND
NA
ND
0.73
16
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
FWLF-04
ND
< BKGD
< BKGD
2,000"
ND
ND
ND
NA
ND
1.7
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
WLF-01
ND
< BKGD
ND
660"
ND
ND
ND
NA
ND
ND
ND
ND
ND
ND
ND
ND
ND
3.8
ND
ND
ND
WLF-02
ND
< BKGD
ND
890a
ND
ND
ND
NA
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
WLF-03
< BKGD
R
ND
R
ND
ND
ND
NA
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Key at end of table.
-------
Pa
"of 5
Table 4-5 (Cont.)
a The result for total manganese is reported due to the lack of dissolved data.
Key:
< BKGD = Less than the background concentration for the analyte.
NA = Not analyzed.
ND = Not detected.
R = Data rejected for use in the human health risk assessment.
2,3,7,8-TCDD = 2,3,7,8-tetrachlorodibenzo-p-dioxin.
4,4'-DDE = 4,4'-dichlorodiphenyldichloroethene.
00
-------
Page 1 of 1
Table 4-6
POTENTIAL RME RISKS: ON-SITE GROUNDWATER
FROM HUMAN HEALTH RISK ASSESSMENT
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Sample Location
Cancer Risk
Hazard Index
Landfill
AP-5585
AP-5588
AP-5589
AP-5591
AP-5593
AP-6133
AP-6134
AP-6136
AP-6137
AP-6138
AP-6139
FWLF-03
FWLF-04
WLF-01
WLF-02
2E-07
3E-03
1E-04
7E-07
—
3E-05
3E-05
3E-04
3E-05
4E-05
2E-03
8E-06
7E-07
3E-07
—
7E+00
1E+01
9E+00
8E+00
4E+00
3E-01
3E-01
7E+00
8E+00
8E-01
4E+01
5E+00
1E+01
4E+00
5E+00
Coal Storage Yard
3559A"
3595-01"
3595-02"
3595-03"
99"
AP-5508
AP-5509
AP-5510
AP-5511
AP-5736
AP-6142
AP-6143
MW-1D
MW-2D
MW-2S
PS-1
PS-2
PS-3
PS-4
WS-119
3E-06
4E-06
7E-06
1E-06
5E-06
—
1E-03
—
—
5E-06
53-05
5E-06
9E-07
6E-06
1E-05
3E-07
1E-06
9E-07
2E-04
4E-04
2E-02
1E+01
6E+00
1E+01
3E+00
2E+00
—
2E+00
73+00
1E+00
4E-01
5E-02
8E-03
5E-02
3E-02
—
2E-02
1E-03
6E-01
5E-02
8 Potential risks associated with current groundwater use from existing wells.
Key:
COPC = Chemical of potential concern.
— = Carcinogenic or noncarcinogenic COPCs not detected.
RME = Reasonable maximum exposure.
64
-------
CORPS OF ENGINEERS
U.S^RMY
OFF ROAD VEHICLE RECREATIONAL AREA
NOTE: ONLY WELLS WITH POSITIVE DETECTIONS OF COPCS ARE SHOWN
LEGEND
TRAIL DRAINAGE
ROAD •*• WETLAND
CANCER RISK
o Not Calculated/No
w Carcinogenic COPCs
• =1E-6 and <1E-5
• >=1E-5 and <1E-4
•} > 1E-4
FORT WAINWRIGHT KEY PLAN
SCALE IN FEET
750
1500
J ecology and environment, inc.
') Intemotkxlol Spoctoliats n th> Enwwmait
2250
U.S. ARMY
ENGINEER DISTRICT, ALASKA
CORPS OF ENGINEERS
ANCHORAGE, ALASKA
Figure 4-1
TOTAL EXCESS LIFETIME CANCER RISKS ASSOCIATED
WITH GROUNDWATER AT THE LANDFILL SOURCE AREA
(RME ASSUMPTIONS)
FAIRBANKS
OPERABLE UNIT 4
ALASKA
SIZE
JOB. NO.
JT2000
FILE NO.
JT24-1A
DATE:
05-17-96
PLATE
-------
•
CORPS OF ENGINEERS
U.S. ARMY
o Not Calculated/No
Carcinogenic COPCs
FORT WAINWRIGHT KEY PLAN
SCALE N FEET
U.S. ARMY
ENGINEER DISTRICT, ALASKA
CORPS OF ENGINEERS
ANCHORAGE. ALASKA
ecology ana environment, inc.
htemaUonal Spedallsts In the Environment
Figure 4—2
TOTAL EXCESS LIFETIME CANCER RISKS ASSOCIATED
WITH GROUNDWATER AT THE COAL STORAGE YARD AREA
(RME ASSUMPTIONS)
OPERABLE UNIT 4
FAIRBANKS
-------
CORPS OF ENGINEERS
U.S ARMY
DRAINAGE
•*- WETLAND
Not Calculated/No
Carcinogenic COPCs
>=1 and <20
>=10 and <20
>=20 and <40
FORT WAINWRIGHT KEY PLAN
SCALE IN FEET
750 1500
U.S. ARMY
ENGINEER DISTRICT, ALASKA
CORPS OF ENGINEERS
ANCHORAGE, ALASKA
ecology and environment, inc.
International Spadaliati hi tho Environment
Figure 4-3
TOTAL HAZARD INDICES ASSOCIATED WITH
GROUNDWATER AT THE LANDFILL SOURCE AREA
(RME ASSUMPTIONS)
FAIRBANKS OPERABLE UNIT 4 ALASKA
JOB. NO.
JT2000
NOTE: ONLY WELLS WITH POSITIVE DETECTIONS OF COPCS ARE SHOWN
-------
CORPS OF ENGINEERS
U.S. ARMY
00
Not Cakulatod/No
Carcinogenic COPCs
<1
A >=1 and <20
• >=10 and <20
>=20 and <40
FORT WAINWRIGHT KEY PLAN
SCALE IN FEET
U.S. ARMY
ENGINEER DISTRICT, ALASKA
CORPS OF ENGINEERS
ANCHORAGE, ALASKA
ecology and environment, inc.
htematfonul Specialists In the Environment
Figure 4-4
TOTAL HAZARD INDICES ASSOCIATED WITH
GROUNDWATER AT THE COAL STORAGE YARD SOURCE AREA
(RWE ASSUMPTIONS)
OPERABLE UNIT 4
FAIRBANKS
-------
-------
5.0 DESCRIPTION OF ALTERNATIVES
5.1 NEED FOR REMEDIAL ACTION
Actual or threatened releases of hazardous substances from the OU-4 source areas, if not addressed
by the response actions selected in this ROD, may present a threat to human health, welfare, or the
environment. Remedial action is necessary at the Landfill and CSY to protect human health and the
environment.
Groundwater is the only source of potable water for Fort Wainwright. The Fort Wainwright aquifer
is unconfmed except in areas of permafrost. The presence of discontinuous permafrost in the OU-4
source areas creates a complex groundwater hydrology that is difficult to characterize or model.
Contaminated soil and Landfill waste act as an ongoing source of contamination to the groundwater.
Remedial action is recommended to protect groundwater.
5.1.1 Landfill Source Area
The specific reasons for conducting remedial actions at the Landfill source area are provided below,
with the primary emphasis being protection of groundwater:
• VOCs and semi-volatile organic compounds in groundwater,
downgradient of the Landfill, are present at concentrations above
federal MCLs; and
• VOCs and semi-VOCs in groundwater pose a potential risk to
downgradient groundwater users.
The Chena River is located approximately 0.25 mile hydraulically downgradient of the Landfill. The
groundwater intakes for the City of Fairbanks are downgradient of this location and within close
proximity of the Chena River. The RI/FS determined that groundwater generally flows in a
southwest direction toward the Chena River in the shallow aquifer zone at the Landfill. Limited
sampling did not indicate contamination in the subpermafrost aquifer zone, which flows in a westerly
direction. Although contamination was not found in the deep aquifer, the complexity of the aquifer
conditions at the Landfill source area made it difficult to determine whether all potential thaw
channels were identified. Potential thaw channels could transport contaminants to the deeper aquifer,
which travels in a western direction, or movement under the Chena River to the southern side of the
main post area may occur. It was determined by the project managers that adequate and sufficient
information about Landfill subsurface hydrology exists and that further investigation is unlikely to
result in significant additional information that could be used in remedial decision making.
5.1.2 Coal Storage Yard Source Area
The specific reasons for conducting remedial actions at the CSY are provided below, with the primary
focus being protection of groundwater:
• VOCs and semi-VOCs in groundwater, underlying the CSY, are
present at concentrations exceeding federal MCLs;
69
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• VOCs and semi-VOCs in groundwater present a potential risk to
downgradient users; and
• Petroleum- and BTEX-contaminated surface and subsurface soils act as
a continuing source of groundwater contamination because of shallow
aquifer conditions and annual groundwater fluctuations. These
contaminants are present at concentrations above State of Alaska
requirements for soil cleanup.
The RI/FS determined that groundwater generally flows in a northwest direction at the CSY. The
main post potable water supply wells are located less than 900 feet downgradient of the source, in the
same aquifer and at approximately the same depths as the identified groundwater contamination at the
CSY. Backup potable supply wells are located within 500 feet of the CSY. Active soil and
groundwater treatment is necessary to contain this plume and prevent migration.
5.2 REMEDIAL ACTION OBJECTIVES
Table 5-1 summarizes the chemical-specific cleanup goals for groundwater at the Landfill.
5.2.1 Landfill Source Area
The remedial action objectives (RAOs) for the Landf.ll are as follows:
5.2.1.1 Groundwater
• Restore groundwater to its beneficial use of drinking water quality
within a reasonable time frame;
• Reduce further migration of contaminated groundwater from the
source areas; and
• Prevent use of groundwater containing contaminants at levels above
federal MCLs and Alaska Water Quality Standards (AWQS; 18 Alaska
Administrative Code [AAC] 70); and
• Use natural attenuation to attain AWQS (18 AAC 70).
5.2.2 Coal Storage Yard Source Area
Table 5-2 summarizes the chemical-specific cleanup goals for groundwater and soil at the CSY.
The RAOs for the CSY are as follows:
5.2.2.1 Groundwater
• Restore groundwater to its beneficial use of drinking water quality
within a reasonable time frame;
70
-------
• Reduce further migration of contaminated groundwater from the
source areas;
• Prevent use of groundwater containing contaminants at levels above
federal MCLs and AWQS (18 AAC 70); and
• Use natural attenuation to attain AWQS (18 AAC 70).
5.2.2.2 Soil
• Prevent migration of soil contaminants to groundwater that could
result in groundwater contamination and exceedances of federal MCLs
and AWQS (18 AAC 70).
5.3 GOALS OF REMEDIAL ACTION
The overall goal of a remedial action is to provide the most effective mechanism for protecting human
health and the environment from contaminated media associated with a site. To facilitate selection of
the most appropriate remedial action, source area-specific cleanup objectives that specify the
contaminants of concern in each medium of interest, exposure pathways and receptors, and an
acceptable contaminant level or range of levels that is protective of human health and the environment
have been developed. The remediation goals identified in Tables 5-1 and 5-2 have been established
for the specific contaminants of concern determined to require remedial action at both source areas.
These goals are intended for the areas where active remediation will occur.
RAOs are based on either human health risk estimates that exceed or fall within 1 x 10"6 to 1 x 10"4
risk range or federal and state applicable or relevant and appropriate requirements (ARARs). All
groundwater RAOs are based on federal or state MCLs with the exception of 1,1,2,2-trichloroethane.
A 1 x 10"4 RAO was selected for this contaminant. This level is consistent with RAOs established for
other solvents for the OU-4 source areas. An RAO for vinyl chloride is provided even though MCL
exceedances have not been detected to date at the Landfill. This cleanup goal is specified to provide
for action in the event that the vinyl chloride concentration increases as degradation of TCE occurs.
Monitoring at the Landfill and CSY will be conducted to ensure that RAOs are achieved. The goal of
this monitoring will be:
• To ensure that no off-source migration of contaminants is occurring;
• To indicate contaminant concentration and compliance with federal
MCLs; and
• To determine whether natural attenuation is occurring at the source
areas.
5.4 SIGNIFICANT APPLICABLE OR RELEVANT AND APPROPRIATE
REQUIREMENTS
A full list of ARARs can be found in Section 8. The following ARARs are the most significant
71
-------
regulations that apply to the remedy selections for the Landfill and CSV:
• Federal and state MCLs are relevant and appropriate for groundwater.
This sets the active remediation goals for groundwater. AWQS (18
AAC 70) are also applicable; and
• Alaska Oil Pollution regulations are applicable, and Alaska regulations
for leaking USTs are relevant and appropriate. These regulations
require cleanup of petroleum-contaminated soils to protect
groundwater quality.
5.5 DESCRIPTION OF ALTERNATIVES
5.5.1 Landfill Source Area
Remedial alternatives for the Landfill are described below. Numerous assumptions were made in
order to determine cleanup time frames. These values should be considered as estimates, but are
comparable within the alternatives provided for this source area.
5.5.1.1 Alternative 1: No Action
The no-action alternative for the Landfill source area involves no environmental monitoring,
institutional controls, or remedial action and would leave the VOC- and semi-VOC-contaminated
groundwater in its present state. The landfill materials would continue to be subjected to surface
water runoff and infiltration, as well as vertical seepage, which could cause surface water
contamination and further contamination of the groundwater. The groundwater plume would continue
to migrate in the direction of groundwater flow through the downgradient portion of the aquifer,
potentially discharging to or migrating beneath the Chena River. Development of the no-action
alternative is required by the NCP to provide a basis of comparison for the remaining alternatives,
serving as a baseline reflecting current conditions without any cleanup effort. The no-action
alternative was evaluated consistent with NCP requirements. No present worth, capital, operation and
maintenance (O&M), or groundwater monitoring costs are associated with this no-action alternative.
5.5.1.2 Alternative 2: Institutional Controls, Natural Attenuation, and Groundwater
Monitoring/Evaluation
Institutional controls for the Landfill source area could include access restrictions (i.e., posted signs,
fencing around the inactive portion of the Landfill, 6-foot industrial-grade security fence with
appropriate entry gates, deed restrictions on future land use, restrictions on groundwater well
installation, restrictions on the use of wells, and well use advisories). No action that would reduce
the source of contamination to the groundwater (i.e., leaching of Landfill wastes) would occur. The
VOC- and semi-VOC-contaminated groundwater would remain as it currently exists at this source
area, thereby not reducing contaminant concentrations except through natural processes. However,
institutional controls would decrease or minimize human or wildlife exposure to contaminants.
Periodic inspections and maintenance of the institutional controls would be conducted.
Natural attenuation occurs over time and is the reduction of contaminant concentrations in the
environment through biological processes (aerobic and anaerobic biodegradation and plant and animal
72
-------
uptake), physical phenomena (advection, dispersion, dilution, diffusion, volatilization and
sorption/desorption), and chemical reactions (ion exchange, complexation, and abiotic
transformation). Transport (dilution) appeared to be the primary mechanism in the natural attenuation
process for groundwater contaminants because of the proximity of the Chena River to the area of
known groundwater contamination. Using a conservative average calculated gradient of 0.0005 foot
per foot (foot/foot), 25% porosity, and a hydraulic conductivity of 600 feet per day (feet/day), a
groundwater velocity of 1.2 feet/day was calculated. Migration of the groundwater would progress
toward the Chena River (approximately 1,500 feet downgradient) over a period of approximately 3.5
years. In order to account for sorption/desorption characteristics of the groundwater contaminants, a
general retardation factor of 10 was applied to the estimate, resulting in a migration time of 35 years.
Because of the complex nature of the aquifer, and limited subsurface data over the 1,500-foot
migration path, a conservative uncertainty factor of 50% was applied to the estimated 35-year
migration, which resulted in an overall groundwater attenuation of 70 years. It is estimated that an
additional 15 years would be required for contamination in soils (i.e., Landfill waste) to naturally
attenuate and cease acting as a source of contamination to groundwater. This results in an estimated
time frame of 85 years for groundwater to naturally attenuate to cleanup standards. However,
because numerous assumptions were made in this estimate and because no source control will be
provided, it is likely that the actual time frame for Landfill material degradation will be much longer.
This would result in a longer period of time to achieve Alaska Water Quality Standards.
Environmental monitoring would be performed to obtain information on the effectiveness of the
attenuation process in remediating the contamination as well as to track the extent of contaminant
migration from the site. To the extent practicable, this would be conducted using existing wells that
are screened in geological zones hydraulically connected with the contamination source, supplemented
by installing groundwater monitoring wells when required. Upgradient wells would be used to
provide information on the background groundwater quality at a source. Downgradient wells would
be used to monitor the extent of contaminant migration, change in flow direction, or the occurrence
of degradation products to protect downgradient drinking water wells.
Monitoring would include analysis for the contaminants that exceeded the MCLs and RBCs as
specified in the RAOs for the Landfill source area. Sample collection, analysis, and data evaluation
would continue until sufficient data regarding changes in contaminant plume migration and attenuation
rates are gathered. Evaluation would include potential seasonal fluctuations in groundwater
contaminant concentrations. The frequency of monitoring would be specially defined during the post-
ROD activities.
The total estimated present worth cost of this alternative is $1,091,000, which includes $82,000 for
capital costs, $10,000 for annual O&M, and $999,000 for annual groundwater monitoring. For
costing purposes, it was assumed that the fencing would be installed around the area of contamination
(i.e., inactive portion of the Landfill) and that there would be one monitoring event per year for 30
years. The estimated time frame for cleanup goals to be achieved and for monitoring to be performed
was 85 years.
73
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5.5.1.3 Alternative 3: A phased approach involving capping of the soils in the older,
inactive portion of the Landfill, natural attenuation of groundwater; groundwater
monitoring/evaluation; and institutional controls. Phase 2, if necessary, would
involve evaluation and implementation of an active groundwater treatment
system.
Alternative 3 is a phased approach, with Phase 1 involving capping of the older, inactive portion of
the Landfill with low-permeable soil; natural attenuation of groundwater; groundwater monitoring and
evaluation; and institutional controls. Phase 2 would involve evaluation and implementation of an
active groundwater treatment system (as described in Landfill Alternative 4), if deemed necessary.
Reference Landfill Alternative 2 for a description of institutional controls, natural attenuation, and
groundwater monitoring for the Landfill source area. It is anticipated that the capping of the inactive
portion of the Landfill will constitutes a final cover under ADEC regulations. The active portion of
the Landfill will be capped at the time of closure, as required by ADEC; however, this will not be
accomplished under CERCLA.
The cap for the inactive portion of the Landfill would be single-layered and consist of native soils
with permeability no greater than 1 x 10~5 centimeters per second (cm/sec). In addition, the thickness
of the infiltration and erosion layer will be a minimum of 18 and 6 inches, respectively. The area
requiring a cap is estimated to be 350,000 square feet (approximately 8 acres) using an estimated
26,000 cubic yards of soil. Vegetative removal, site regrading, and active Landfill access will be
done before cap installation. This cap will cover the area of the known petroleum spill. This layer
would be suitable to maintain native vegetative growth or grasses, as required by RCRA and ADEC
for Landfill closure. In the event that the cap does not promote natural drainage, drainage control
structures such as dikes, berms, or waterways would be installed to remove water and prevent
ponding and erosion. The cap would require periodic maintenance (probably once a year); however,
more frequent inspections will be conducted during the first six months because problems such as
erosion, settlement, or subsidence would most likely appear during this time frame. Proper and
timely maintenance of any defects would be required to preserve the integrity of the cap.
Maintenance would be limited to periodic mowing of the vegetation or grass to prevent naturally
occurring invasion by deep-rooted vegetation and/or burrowing animals. The need for a gas
collection system will be addressed during design; however, in the event a system is deemed
necessary, one possible scheme that could be implemented involves installing vertical gas wells over
25% of the inactive portion of the Landfill at an average depth of 10 feet into the Landfill wastes.
Under Phase 1, existing groundwater contamination would meet RAOs through natural attenuation,
thus providing a permanent remedy for groundwater contamination. Because the soils would be
capped and surface water flow controlled, production of leachate is expected to significantly decrease;
therefore, groundwater would be expected to naturally attenuate faster than if no cap were placed on
the soils. For costing purposes, natural attenuation of groundwater to federal MCLs was estimated to
take 70 years, as detailed in Landfill Alternative 2. Groundwater monitoring/evaluation would be
performed to assess when the groundwater has naturally attenuated and to evaluate any impact to
downgradient receptors. The point of compliance for achieving remediation goals will be at the
downgradient edge of the Landfill in the known thaw channels, utilizing existing wells to the extent
practicable. In the event it is found, through monitoring, that natural attenuation of groundwater is
not progressing as expected, or that there is not a significant reduction in leachate, or that site
conditions change, or it is determined that human or ecological receptors are being adversely
impacted, Phase 2, which calls for evaluation of implementation of an active groundwater treatment
74
-------
system, would be initiated. Should an active groundwater treatment system be necessary, it would be
designed to reduce contaminants in groundwater to below MCLs or RBCs as specified in the RAOs,
after which it would be left to naturally attenuate to AWQS.
Cost data generated for this alternative is based on expected Phase 1 activities only. In the event that
Phase 2 is considered necessary, cost data will be generated at that time. The total estimated present
worth cost of this alternative is $1,620,000, which includes $476,000 for capital costs, $150,000 for
annual O&M, and $994,000 for annual groundwater monitoring. For costing purposes, it was
assumed that the fencing would be installed around the area of contamination (i.e., inactive portion of
the Landfill) and that there would be one monitoring event per year. The estimated time frame for
cleanup goals to be achieved and for monitoring to be performed was 70 years.
5.5.1.4 Alternative 4: On-Site Treatment of Groundwater Via Extraction and Treatment
(Air Stripping with Liquid-Phase Carbon Adsorption of Ultraviolet Oxidation),
Groundwater Monitoring/Evaluation, and Institutional Controls
Alternative 4 involves on-site groundwater treatment via extraction and treatment (air stripping with
liquid-phase carbon adsorption, or ultraviolet [UV] oxidation), groundwater monitoring/evaluation,
and institutional controls. Reference Landfill Alternative 2 for a description of institutional controls
and groundwater monitoring for the Landfill source a~ea. Because air stripping is detrimentally
affected by cold temperatures and the costs for both air stripping and UV oxidation are comparable,
UV would be favored. Other technologies could be considered during detail design.
Groundwater treatment for this alternative includes extraction, through wells and pumps, and
treatment of groundwater aboveground to reduce VOC- and semi-VOC contaminated concentrations to
below MCLs or RBCs, as specified in the RAOs. The groundwater extraction system would be
designed to hydraulically contain the contaminant plume and keep contaminants from migrating
farther through the aquifer by installing approximately six wells, at an estimated depth of 5 feet below
the top of the aquifer. These wells would extract a total of approximately 150 gallons per minute
(gpm). Recharge is expected to be instantaneous because of the aquifer characteristics. The UV
oxidation treatment system would produce no vapors. A clarifier, sand filter, or bag filter may be
incorporated following UV oxidation to remove extracted metals such as arsenic and manganese to
below appropriate regulatory standards (i.e., National Pollutant Discharge Elimination System
[NPDES] discharge limits). The treated groundwater would be directly discharged to the Chena
River via an open channel or piping. After initiation of the groundwater extraction and treatment
system, a groundwater monitoring/evaluation program would be implemented. This program would
monitor the progress of remediation and proper operation of the groundwater treatment system,
comply with NPDES discharge limits through sampling and analysis of the discharge effluent, and be
used to modify the extraction system to make it more effective.
A simple volumetric calculation was used to estimate the cleanup time due to the nature of the
groundwater contaminants at the Landfill source area. A radius of 210 feet around each proposed
recovery well, a saturated thickness of 75 feet (which accounts for vertical transport), and a porosity
of 25% was used to define the volume of groundwater contamination requiring remediation.
Applying the lower potential recovery rate of 75 gpm resulted in one pore volume removal in
approximately 0.5 per year. Using a 10-pore-volume removal to account for sorption/desorption
processes resulted in a five-year estimate. However, because of the complex nature of the aquifer
matrix and uncertain impact of the permafrost on contaminant recovery, a removal efficiency of 50%
75
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was used to compute the estimated cleanup time of 10 years for ground water. Because Landfill waste
would have to biodegrade before leaching to groundwater would cease, it is expected that 25 years
would be required for groundwater to reach MCLs or RBCs through treatment. AWQS would be met
through natural attenuation. Actual flow rates, well locations, optimum number of wells, and actual
time frame estimates would be determined during the design phase.
The total estimated present worth cost of this alternative is $8,365,000, which includes $1,319,000
for capital costs, $6,228,000 for annual O&M, and $818,000 for annual groundwater monitoring.
For costing purposes, it was assumed that the fencing would be installed around the area of
contamination (i.e., the inactive portion of the Landfill) and that there would be one monitoring event
per year. The estimated time frame for cleanup goals to be achieved and for monitoring to be
performed was 25 years.
5.5.1.5 Alternative 5: Capping of the Older, Inactive Portion of the Landfill, On-Site
Treatment of Groundwater Via Extraction and Treatment (Air Stripping with
Liquid- Phase Carbon Adsorption or Ultraviolet Oxidation), Groundwater
Monitoring/Evaluation, and Institutional Controls
Alternative 5 involves capping of the older, inactive portion of the Landfill and on-site treatment of
groundwater via extraction and treatment (air stripping with liquid-phase carbon adsorption or UV
oxidation), groundwater monitoring/evaluation, and institutional controls. Reference Landfill
Alternatives 2 and 4 for a description of institutional controls and groundwater monitoring as well as
a description of the groundwater extraction and treatment system for the Landfill source area.
The total estimated present worth cost of this alternative is $6,033,000, which includes $1,709,000
for capital costs, $3,831,000 for annual O&M, and $493,000 for annual groundwater monitoring.
For costing purposes, it was assumed that the fencing would be installed around the area of
contamination (i.e., the inactive portion of the Landfill) and that there would be one monitoring event
per year. The estimated time frame for cleanup goals to be achieved and for monitoring to be
performed was 10 years.
5.5.2 Coal Storage Yard Source Area
Preliminary remedial alternatives for the CSV area are described below. Numerous assumptions had
to be made in order to determine cleanup time frames. These values should be considered as
estimates, but are comparable within the alternatives provided for this source area.
5.5.2.1 Alternative 1: No Action
The no-action alternative for the CSV source area involves no environmental monitoring, institutional
controls, or remedial action and would leave the petroleum-contaminated soils and VOC- and semi-
VOC-contaminated groundwater in their present state. The contaminated soils would continue to be
subjected to surface water runoff and infiltration, as well as vertical seepage, which could cause
surface water contamination and further contamination of the groundwater. The groundwater plume
would continue to migrate in the direction of groundwater flow through the downgradient portion of
the aquifer, potentially affecting the Post drinking water wells and the Chena River. Development of
the no-action alternative is required by the NCP to provide a basis of comparison for the remaining
alternatives, serving as a baseline reflecting current conditions without any cleanup effort. The no-
76
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action alternative was evaluated consistent with NCP requirements. No present worth, capital, O&M,
or groundwater monitoring costs are associated with this no-action alternative.
5.5.2.2 Alternative 2: Institutional Controls, Natural Attenuation, and Groundwater
Monitoring/Evaluation
Institutional controls for the CSV source area would include access restrictions (i.e., posted signs,
deed restrictions on future land use, restrictions on groundwater well installation, restrictions on the
use of wells, and well use advisories). The contaminated soils and groundwater would remain
untreated, thereby not reducing contaminant concentrations or the threat to Post water supply wells.
However, institutional controls would decrease or minimize human or wildlife exposure to
contaminants. Periodic inspections and maintenance of the institutional controls would be conducted.
Natural attenuation occurs over time and is the reduction of contaminant concentrations in the
environment through biological processes (aerobic and anaerobic biodegradation and plant and animal
uptake), physical phenomena (advection, dispersion, dilution, diffusion, volatilization, and
sorption/desorption), and chemical reactions (ion exchange, complexation, and abiotic
transformation). Estimation of natural attenuation rates of soil contamination at the CSV consisted of
evaluation of two primary mechanisms: degradation and transport. Because of the characteristic slow
rate of fuel degradation, it is not considered a significant factor in the attenuation process. However,
transport or leaching of soil contamination to the groundwater appears to represent a major factor in
the attenuation process. Based on an annual groundwater recharge rate of 6 inches per year and
considering reductions of soil contaminant concentrations due to leaching over time, it is estimated
that attenuation of the soil contamination will be accomplished in 15 years.
Groundwater natural attenuation rates at the CSV area were estimated similar to the natural
attenuation rates at the Landfill area. The major difference is that a conservative average calculated
gradient of 0.0021 foot/foot was used to yield a groundwater velocity of 5 feet/day at the CSY area.
Migration of groundwater would progress toward the Chena River (approximately 2,000 feet
downgradient) over a period of approximately one year. This contaminant plume would intercept
Post water supply wells, located 900 feet from the CSY, before reaching the Chena River. To
account for sorption/desorption characteristics of the groundwater contaminants, a general retardation
factor of 10 was applied to the estimate, resulting in a migration time of 10 years. Because of the
complex nature of the aquifer and limited subsurface data over a 2,000-foot migration path, a
conservative uncertainty factor of 50% was applied to the estimated 10-year migration, which
produced an overall groundwater attenuation of 20 years. Because the contaminants in the soil would
have to naturally attenuate before the groundwater could do so, groundwater is expected to naturally
attenuate to AWQS in 35 years.
Environmental monitoring and data evaluation will be performed to obtain information on the
effectiveness of the attenuation process in remediating the contamination as well as to track the extent
of contaminant migration from the site. To the extent practicable, this will be conducted using
existing wells that are screened in geological zones hydraulically connected with the contamination
source, supplemented by installing groundwater monitoring wells when required. Upgradient wells
would be used to provide information on the background groundwater quality at a source.
Downgradient wells would be used to monitor the extent of contaminant migration, change in flow
direction, or the occurrence of degradation products that could affect downgradient drinking water
wells.
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Monitoring requirements that would be followed will target the contaminants that were found to
exceed the MCLs and RBCs, as specified in the RAOs for the CSV source area. Sample collection
and analysis would continue until sufficient data regarding changes in contaminant plume migration
(including potential seasonal fluctuations in groundwater contaminant concentrations) are gathered.
The frequency of monitoring will be specially defined during the post-ROD activities.
The total estimated present worth cost for this alternative is $955,000, which includes $53,000 for
capital costs, $8,000 for annual O&M, and $894,000 for annual groundwater monitoring. The
estimated time frame for cleanup goals to be reached and for monitoring to be performed was 35
years.
5.5.2.3 Alternative 3: Excavation and Off-Site Treatment of Soils Via Low-Temperature
Thermal Desorption, Natural Attenuation, Groundwater Monitoring/Evaluation,
and Institutional Controls
Alternative 3 involves excavation and treatment of soils through low-temperature thermal desorption
(LTTD), natural attenuation of groundwater, groundwater monitoring/evaluation, and institutional
controls. Reference CSY Alternative 2 for a description of institutional controls, natural attenuation,
and groundwater monitoring for the CSY source area.
Approximately 223 cubic yards of petroleum-contaminated soils in the CSY area require remediation.
Excavation would be easy to implement in two of the areas of contamination within the CSY source
area because they would be excavated to relatively shallow depths and groundwater would not be
encountered. However, at the third area, excavation would not be feasible after groundwater was
encountered (between 20 and 25 feet BGS; see Figure 5-1). The remaining soils, which could be
highly contaminated, would be left in-place to naturally attenuate. Verification sampling would be
performed, and excavated areas would be backfilled with clean soil.
Excavation of the contaminated soil would require a preparation program for the areas of excavation
within the CSY area, including clearing and grubbing of the site and construction of a
decontamination pad. Excavated contaminated soils would be temporarily stored on site in a
designated staging area. This area would be constructed using an impermeable liner, surface water
controls, a leachate collection system, and a cover.
The total estimated present worth cost for this alternative is $983,000, which includes $126,000 for
capital costs, $8,000 for annual O&M, and $849,000 for annual groundwater monitoring. Costs are
sensitive to the tons of soil to be treated by LTTD. For costing purposes, it was assumed that there
would be one monitoring event per year. The estimated time frame for cleanup goals to be reached
and for monitoring to be performed was 20 years.
5.5.2.4 Alternative 4: Excavation and Off-Site Treatment of Soils Via Low-Thermal
Temperature Desorption, On-Site Treatment of Groundwater Via Extraction and
Treatment (Air Stripping with Liquid-Phase Carbon Adsorption or Ultraviolet
Oxidation), Groundwater Monitoring/Evaluation, and Institutional Controls
Alternative 4 involves excavation and treatment of soils through LTTD as described in CSY
Alternative 3, on-site treatment of groundwater via extraction and treatment (air stripping with liquid-
phase carbon adsorption or UV oxidation), groundwater monitoring/evaluation, and institutional
78
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controls. Because air stripping is detrimentally affected by cold temperatures and the costs for both
air stripping and UV oxidation are comparable, UV would be favored. Reference CSY Alternative 2
for a description of institutional controls and groundwater monitoring for the CSY source area.
The groundwater extraction system for the CSY source area would consist of an estimated seven
extraction wells, approximately 5 feet below the top of the aquifer, pumping groundwater at a total
estimated rate of 70 to 140 gpm. A variability in the proposed pumping rates is due to uncertainty in
the transmissivity of the aquifer matrix. For purposes of cost estimating, the higher estimated flow
rate would be used as the proposed flow rate for each of the recovery wells.
A simplified volumetric calculation was used because of the nature of the groundwater contaminants
at the site. A radius of 180 feet around each of the proposed recovery wells, a saturated thickness of
75 feet (which accounts for vertical transport), and a porosity of 25% were used to define the volume
of groundwater contamination requiring remediation. Applying the lower potential recovery rate of
70 gpm, accounting for sorption/desorption processes, and using the removal efficiency of 50%,
resulted in an estimated cleanup time of eight years for the treatment of groundwater to federal
MCLs, with natural attenuation to AWQS. Contaminated soils will be removed to the extent
practicable. However, excavation would not be feasible after groundwater was encountered (between
20 and 25 feet BGS). The remaining soils would be left in place to naturally attenuate. However,
for purposes of cost estimating, it was assumed that all contaminated soils were excavated, thereby
removing the source of groundwater contamination and eliminating contaminant leaching to
groundwater. Using the source removal assumption, the time required to treat the aquifer would be
relatively short. Actual flow rates, well locations, optimum number of wells, and actual time frame
estimates would be determined during the design phase.
The total estimated present worth cost for this alternative is $3,113,000, which includes $1,114,000
for capital costs, $1,627,000 for annual O&M, and $372,000 for annual groundwater monitoring.
The most sensitive costs for this alternative were found to be associated with the tons of soil treated
via LTTD, discussed in Alternative 3. Additionally, costs were found to be sensitive to the flow rate
for the groundwater pump-and-treat system. The estimated time frame for cleanup goals to be
reached and for monitoring to be performed was eight years.
5.5.2.5 Alternative 5: In Situ Treatment of Soils Via Vacuum Extraction System
Enhanced by Steam Injection or Bioventing, Natural Attenuation, Groundwater
Monitoring/Evaluation, and Institutional Controls
Alternative 5 involves treatment of soils in place through a vapor extraction system (VES), which
could be enhanced by steam injection and bioventing, natural attenuation of groundwater, and
institutional controls. Reference CSY Alternative 2 for a description of natural attenuation,
groundwater monitoring, and institutional controls for the CSY source area. This system would be
operational year-round.
The VES collects soil vapors from the subsurface soils by applying a vacuum at a series of extraction
points. The vacuum would draw vapors from the contaminated soils and would decrease the pressure
around the soil particles, thereby releasing additional volatiles. This vapor removal could be
maximized by the use of "pulsed venting," where the blower would be turned off and on to allow the
soil vapor to re-equilibrate, or by venting different combinations of wells to change the flow field.
Under current air quality regulations, no off-gas treatment is required.
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This system could be enhanced by bioventing, which injects clean air into the soils through a separate
air injection system. This re-injection of clean air enhances air movement through the soil and
stimulates biodegradation. Air injection also assists in controlling flow paths of the extracted vapor,
which results in more efficient contaminant removal. Bioventing, if chosen as an enhancement to
VES, would be evaluated before implementation and tested during the Design Verification Study.
Steam injection could be used rather than bioventing to thermally enhance vacuum extraction. Steam
would be injected into the contaminated soils through the injection wells to help volatilize the organics
in the soil. These volatilized organics would be recovered through the extraction wells. Steam
injection would also be expected to thaw the soil during the winter months. Steam injection, if
chosen as an enhancement to VES, would be evaluated before implementation and tested during the
Design Verification Study.
The VES would be designed so that its flow rate would be capable of handling three times the volume
of the injection rate; however, pilot or field tests would be conducted in the source areas of the CSY
to determine the actual site-specific design parameters. Those parameters include the determination of
the gas permeability and obtainable flow rates, the radius of influence, initial and final off-gas
concentrations from the VES, water level changes, and vacuum well pressures for full-scale design
and implementation. Regular monitoring of the enhanced VES system would be done to ensure the
progress of cleanup, to estimate the volume of petroleum hydrocarbons removed by the system, and
to establish a timetable for completion of the project.
For costing purposes, it is assumed that the major components of the enhanced VES system would
include two injection wells and two extraction wells; below ground polyvinyl chloride piping, valves,
sampling ports, and vacuum gauges; an injection and extraction centrifugal blower; an air/water
separator; and a heat exchanger. The centrifugal blower would be housed in a temporary building.
The VES would consist of explosion-proof equipment and automatic safety devices that would
deactivate the system if the treatment building interior atmosphere were to exceed 20% of the lower
explosive limit. Any water extracted from the air/water separator will be treated by a carbon
filtration system. Costs for enhancements to the VES system, if incorporated into the design, are
considered minimal and will be calculated into the construction cost estimates during the Remedial
Design.
The total estimated present worth cost for this alternative is $1,046,000, which includes $153,000 for
capital costs, $115,000 for annual O&M, and $778,000 for annual groundwater monitoring. Because
of climatic conditions at Fort Wainwright, it is estimated that the VES would operate for three years
to achieve RAOs. In order for the groundwater to begin to naturally attenuate, the soil needs to be
fully remediated. With groundwater estimated to naturally attenuate to AWQS in 20 years after the
soil is remediated, a total of 23 years is required for the remediation of both soils and groundwater.
5.5.2.6 Alternative 6: In Situ Treatment of Soils Via Vacuum Extraction Enhanced by
Steam Injection or Bioventing, In Situ Treatment of Groundwater Via Air
Sparging, Groundwater Monitoring/Evaluation, and Institutional Controls
Alternative 6 involves treatment of soils in place through a VES, which could be enhanced by steam
injection or bioventing as discussed in CSY Alternative 5. Contaminated groundwater would be
treated on site via air sparging and groundwater monitoring/evaluation. Reference CSY Alternative 2
for a description of groundwater monitoring and institutional controls for the CSY source area.
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Two major differences distinguish the air sparging system (AS) from the VES/bioventing or steam
injection systems described in CSY Alternative 5. First, with AS, the air is injected below the
groundwater table, unlike VES/bioventing or steam injection in which the air is injected above the
groundwater table to enhance biodegradation of VOCs and to promote their movement to extraction
wells. Secondly, each injection well of the AS system would be collocated with an extraction well to
capture the vadose zone air stream that carries volatile hydrocarbons.
Similar to VES/bioventing or steam injection, the AS system would consist of extraction and injection
wells, well piping, a compressor and vacuum blower, an air/water separator, a heat exchanger, a
housing and heating system, and monitoring devices. For costing purposes, it is assumed that the AS
system would require 10 injection and 10 extraction wells. Import and design parameters, such as the
radius of influence of the AS system at different injection flows and pressure, the radius of influence
of the VES, and the pressure and vacuum requirements for effective treatment and effective capture of
volatilized materials, could be determined by pilot testing or by adapting design parameters from
existing VES/AS systems on Fort Wainwright. For costing purposes, it was estimated that VES
coupled with AS would take nine years to remediate soil and groundwater to meet ADEC soil cleanup
goals and for federal MCLs, respectively. Natural attenuation will be used to achieve AWQS for
groundwater once federal MCLs are met.
Estimation of cleanup efficiency using air sparging was based on the relative efficiency of the
sparging technique compared with the pump-and-treat technology. Empirical data on air sparging
indicate cleanup efficiencies of 25% to 50% greater than for pump-and-treat technology. Assuming
the lower range of cleanup efficiency, air sparging would operate simultaneously with enhanced VES
for nine years to ensure optimum efficiency.
The total estimated present worth cost for this alternative is $1,544,000, which includes $364,000 for
capital costs, $730,000 for annual O&M, and $450,000 for annual groundwater monitoring. Costs
for this alternative were found to be most sensitive to the time of treatment via enhanced vacuum
extraction. A cost sensitivity analysis was run for a variation in the time of treatment from minus one
year to plus one year. In addition, enhanced vacuum extraction was found to be cost-sensitive to the
tons of soil to be treated. The estimated time frame for cleanup goals to be reached and for
monitoring to be performed was nine years.
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Page 1 of 2
00
NJ
Table 5-1
CHEMICAL-SPECIFIC CLEANUP GOALS FOR GROUNDWATER
LANDFILL SOURCE AREA
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
CLEANUP GOALS FOR GROUNDWATER
Analyte
ARARs
Federal
MCL
Alaska Drinking
Water Standards
(state MCLs)
Alaska
State
Water Quality
Standards
TBCs
Site RA RBC
HI
10-4
Site-Specific
Ground water*
Background
Corpsb
Remedial
Action
Objective1
Maximum
Detected
Concentration
Site
Cleanup
Goal
Organics 0
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Page 2 of 2
Table 5-1 (Cent.)
Key:
ADEC
ARAR
Corps
HI
MCL
ND
RA
RBC
TBC
TRPH
Value not established.
Alaska Department of Environmental Conservation.
Applicable or relevant and appropriate requirement.
United States Army Corps of Engineers, Alaska District.
Hazard index.
Micrograms per liter.
Maximum contaminant level.
Not detected.
Human health risk assessment.
Risk-based concentration.
To be considered.
Total recoverable petroleum hydrocarbon.
CO
OJ
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Page 1 of 2
00
*>.
Table 5-2
CHEMICAL-SPECIFIC CLEANUP GOALS FOR GROUNDWATER
COAL STORAGE YARD SOURCE AREA
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
CLEANUP GOALS FOR GROUNDWATER
Analyte
ARARS
Federal
MCL
Alaska
Drinking Water
Standards
(state MCL)
Alaska State
Water Quality
Standards
TBCs
Site RA RBC
HI
w-4
Site-Specific
Groundwater*
Background
Corpsb
Remedial
Action
Objective0
Maximum
Detected
Concentration
Site
Cleanup
Goal
Cleanup Goals for Groundwater
Organic; Oig/L)
Benzene
bis(2-Ethylhexyl)phtha!ate
Trichloroethene
Toluene
5
6
5
1,000
5
6
5
1,000
10d
—
5
10d
—
—
—
—
250
220
—
—
NA
2a
NA
NA
5
6
5
1,000
800
110
56
1
5
6
5
1,000
Key at end of table.
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Page 2 of 2
CO
Ul
Table 5-2
CHEMICAL-SPECIFIC CLEANUP GOALS FOR SOIL
COAL STORAGE YARD SOURCE AREA
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
CLEANUP GOALS FOR SOIL
Matrix Score = 39
BTEX = 15 mg/kg
Benzene = 0.5 mg/kg
VPH = 100 mg/kg
EPH = 200 mg/kg
Level Ae >40
Level B 27-40
Level C 21-26
Level D <20
Diesel
Diesel-
range
petroleum
hydrocarbons
(EPH)
100
200
1,000
2,000
Gasoline/Unknown
Gasoline-
range
petroleum
hydrocarbons
(VPH)
50
100
500
1,000
Benzene
0.1
0.5
0.5
0.5
BTEX
10
15
50
100
a Site-specific background groundwater concentration.
Background concentrations from Corps-recommended background value for Fort Wainwright.
c Groundwater remediation goals are based on federal and state MCLs for organic contaminants in public water supply systems (40 CFR 141.147 and 18 AAC 80).
d 18 AAC 70, Water Quality Standards. The regulatory level for BTEX is 10 ng/L.
Level A cleanup goal is applied to the total matrix score of 39 due to the soil acting as an ongoing source of contamination to groundwater.
Key:
ACC
ADEC
ARAR
BTEX
CFR
Corps
W/L
mg/kg
MCL
NA
RA
RBC
TBC
Alaska Administrative Code.
Alaska Department of Environmental Conservation.
Applicable or relevant and appropriate requirement.
Benzene, toluene, ethylbenzene, xylene.
Code of Federal Regulations.
United States Army Corps of Engineers, Alaska District.
Micrograms per liter.
Milligram per kilogram.
Maximum contaminant level.
Not available.
Human Health Risk Assessment.
Risk-based concentrations.
To be considered.
-------
CORPS OF
U.S. ARMY
NGINEERS
FORT WAINWRIGHT KEY PLAN
ENGINEER DISTRICT, ALASKA
ecology and environment, inc.
International Specialists in the Environment
Figure 5-1
SOIL AREAS REQUIRING REMEDIATION
IN COAL STORAGE YARD SOURCE AREA
LOCATION MAP
OPERABLE UNIT 4
JT21-5A.DWG
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6.0 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
In accordance with federal regulations, the five alternatives for the Landfill source area and the six
alternatives for the CSY source area were evaluated based on the nine criteria presented in the NCP.
6.1 LANDFILL SOURCE AREA (COMPARATIVE ANALYSIS OF ALTERNATIVES)
6.1.1 Threshold Criteria
6.1.1.1 Overall Protection of Human Health and the Environment
AH alternatives with the exception of Alternative 1 (no action) would use institutional controls to
prevent the use of contaminated groundwater until cleanup standards are achieved. Alternative 5
would provide the greatest protection and degree of cleanup by capping the Landfill material, which
protects against future groundwater contamination, and treatment of groundwater to address existing
contamination. Alternative 2 would provide some protection to human health and the environment
through institutional controls, which would reduce contact with contamination. Alternative 3 does not
treat current groundwater contamination but focuses on source control and thus prevents future
groundwater contamination. However, Alternative 3 does provide for groundwater treatment in Phase
2 of the alternative, which would protect against current groundwater contamination. Alternative 4
actively remediates groundwater but does nothing to control the contaminant source. Alternatives 3
and 5 would reduce leaching of contaminants to the groundwater by installing a Landfill cap, thereby
reducing the time required to achieve groundwater RAOs. Under Alternatives 2 and 3, groundwater
would be monitored to determine whether natural attenuation of contaminants is progressing as
expected. In the event that it does not, the need for an active groundwater treatment system would be
evaluated under Phase 2 of Alternative 3. Alternatives 4 and 5 actively treat contaminated
groundwater.
6.1.1.2 Compliance with Applicable or Relevant and Appropriate Requirements
Alternatives 4 and 5 and Phase 2 of Alternative 3 are expected to achieve groundwater RAOs more
rapidly than the other alternatives. Alternatives 1 and 2 and Phase 1 of Alternative 3 rely on natural
processes to slowly reduce contaminant concentrations in the groundwater. Under Alternative 3,
groundwater treatment will be evaluated if groundwater contaminant concentrations do not decrease
over time. Alternatives 4 and 5 and Phase 2 of Alternative 3 are expected to achieve federal or state
MCLs or RAOs through active treatment, then AWQS through natural attenuation. The functional
equivalent of NPDES permit requirements must be met to discharge treated groundwater to the Chena
River for Alternatives 4 and 5 and Phase 2 of Alternative 3.
ADEC and relevant and appropriate RCRA solid waste landfill closure requirements for Fort
Wainwright would be met for Alternatives 3 and 5. Alternatives 1, 2, and 4 would not fulfill the
solid waste landfill closure requirements for Fort Wainwright.
6.1.2 Primary Balancing Criteria
6.1.2.1 Long-Term Effectiveness and Permanence
Alternatives 3 and 5 are expected to achieve long-term effectiveness and permanence with respect to
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groundwater cleanup through either active treatment of groundwater, capping a portion of the
Landfill, or a combination of both. Alternative 4 is expected to achieve long-term effectiveness and
permanence with respect to groundwater cleanup but does nothing to prevent continued leaching of
Landfill contaminants to the groundwater. None of the contaminants would be addressed by
Alternatives 1 and 2, except through natural processes. Therefore, Alternatives 1 and 2 would
provide the least effective long-term permanence because neither active treatment of groundwater nor
capping of the Landfill materials will be conducted under these two alternatives.
6.1.2.2 Reduction of Toxicity, Mobility, and Volume Through Treatment
The toxicity and volume of contaminated groundwater would be reduced through Alternatives 4 and 5
and Phase 2 of Alternative 3 because they provide for direct treatment of extracted groundwater.
Furthermore, the hydraulic control provided by the extraction system would limit the mobility of the
groundwater contaminants. Neither Alternatives 1 and 2 nor Phase 1 of Alternative 3 would reduce
toxicity or mobility of contaminants in groundwater through treatment; over time it would reduce
toxicity through natural attenuation.
Although capping of Landfill materials under Alternatives 3 and 5 is not considered treatment, it will
reduce mobility of contaminant leaching to groundwater. Alternatives 1, 2, and 4 do not reduce
mobility of contaminants to the groundwater. None of the alternatives reduce toxicity or volume of
Landfill materials because the contamination would remain under the cap.
6.1.2.3 Short-Term Effectiveness
Alternatives 3 and 5 would pose some short-term potential risks to on-site workers through generation
of dust and noise and through potential exposure to contaminated soils during two months for capping
activities. Alternatives 4 and 5 and Phase 2 of Alternative 3 pose short-term potential risks to on-site
workers during one month of the installation of the extraction and treatment system. These risks
would be minimized by the use of engineering controls and personal protective equipment (PPE).
Natural attenuation of groundwater under Phase 1 of Alternative 3 poses no short-term risks.
Alternatives 1 and 2 do not include active treatment, and therefore, risks would not change over time
except through natural processes. Alternatives 2, 3 (Phase 1), 4, and 5 would meet groundwater
cleanup goals in 85, 70, 25, and 10 years, respectively.
6.1.2.4 Implementability
All alternatives would use readily available technologies and would be feasible to construct.
Alternatives 1 and 2 would be readily implementable because they would require no additional action
other than monitoring or institutional controls. Alternatives 4 and 5 and Phase 2 of Alternative 3,
pilot studies, would be required to determine the best design for the groundwater extraction and
treatment system. Discharge piping would have to be constructed to the Chena River so that treated
groundwater can be discharged. Because air stripping is negatively affected by cold temperatures,
oxidation is favored for treatment of contaminated groundwater.
6.1.2.5 Cost
Based on the information available at the time the alternatives were developed, the estimated costs for
each alternative evaluated for the Landfill source area are in Table 6-1. If monitoring is required for
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a longer period of time because of slower than estimated attenuation rates, then cost would increase
proportionally.
6.1.3 Modifying Criteria
6.1.3.1 State Acceptance
ADEC has been involved with the development of remedial alternatives for OU-4 and agrees with the
selected remedy for the Landfill source area.
6.1.3.2 Community Acceptance
No comments regarding remedial action at OU-4 were received during the comment period. This
may indicate that there is no opposition to any of the preferred alternatives. The Responsiveness
Summary, Appendix B to this document, provides the background of community involvement
activities conducted in association with OU-4.
6.2 COAL STORAGE YARD SOURCE AREA (COMPARATIVE ANALYSIS OF
ALTERNATIVES)
6.2.1 Threshold Criteria
6.2.1.1 Overall Protection of Human Health and the Environment
Alternatives 4 and 6 would provide the greatest protection and degree of cleanup by actively treating
the contaminated soils and groundwater. Alternatives 3 and 5 would protect human health and the
environment from contaminated soils through treatment but would rely on natural attenuation to
remediate groundwater. Alternative 2 would provide some protection to human health and the
environment through institutional controls, which would reduce contact with contamination.
Alternative 1 (No Action) would be the least protective.
6.2.1.2 Compliance with Applicable or Relevant and Appropriate Requirements
Alternative 6 is expected to achieve regulatory requirements more rapidly than the other alternatives
because it includes active soil and groundwater treatment. While Alternative 4 would also achieve
regulatory requirements rapidly, excavation of contaminated soil is limited by depth to groundwater.
Alternatives 3 and 5, which include soil treatment and natural attenuation of groundwater, are
expected to achieve regulatory requirements within a longer time frame. Alternatives 1 and 2 would
rely on natural processes to slowly decrease soil and groundwater contamination. However, under
Alternative 1, compliance with regulatory requirements would not be determined because monitoring
will not be completed. State and federal drinking water standards will be achieved through active
treatment. AWQS would be achieved through natural attenuation under all five alternatives.
6.2.2 Balancing Criteria
6.2.2.1 Long-Term Effectiveness and Permanence
Alternatives 4 and 6 provide long-term effectiveness and permanence through active soil and
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groundwater treatment; Alternative 6 is most effective. Alternatives 3, 4, 5, and 6 provide long-term
groundwater protection through treatment of contaminated soils. Alternatives 5 and 6 provide a more
effective soil treatment than Alternatives 3 and 4 because they address the saturated soils that can not
be excavated. None of the contaminants would be addressed by Alternatives 1 and 2, except through
natural processes. Therefore, Alternatives 1 and 2 would provide the least effective long-term
permanence because active treatment of soil or groundwater will not be conducted under these two
alternatives.
6.2.2.2 Reduction of Toxicity, Mobility, and Volume Through Treatment
The toxicity and mobility of contaminated groundwater would be reduced through Alternative 4,
which provides for direct treatment and hydraulic control of extracted water. The toxicity of
contaminated groundwater would also be reduced through Alternative 6, which provides for in-place
treatment of contaminated groundwater. Although Alternatives 3 and 5 would not reduce the mobility
of contaminants in groundwater, over time, they would reduce toxicity through natural attenuation.
Alternative 5 would treat more soil contaminants than Alternative 3 because it would treat soils under
the active coal pile. Alternatives 3, 4, 5, and 6 involve treatment technologies that would reduce the
toxicity and mobility of soil contaminants. In addition, Alternatives 3 and 4 would reduce the volume
of the contaminated soils of the CSY source area through LTTD. These four alternatives are
expected to be able to reduce the soil contamination to levels that do not pose risks to human health
or the environment.
6.2.2.3 Short-Term Effectiveness
Alternatives 3, 4, 5, and 6 would pose some short-term potential risks to on-site workers during the
estimated two months for excavation of soils and/or installation of the treatment systems. These
risks, however, would be minimized by the use of engineering controls and PPE. Natural attenuation
of groundwater under Alternatives 3 and 5 poses no short-term risks. Alternatives 1 and 2 do not
include active treatment, and therefore, risks would not change over time, except through natural
processes. Alternatives 2, 3, 4, 5, and 6 would meet soil and groundwater cleanup goals in 35, 20,
eight, 23, and nine years, respectively.
6.2.2.4 Implementability
All alternatives would use readily available technologies and would be feasible to construct.
Alternatives 1 and 2 would be readily implementable because they would require no additional action
other than monitoring or institutional controls. Alternatives 3 and 4, which involve movement of the
coal pile, would be difficult to implement. The presence of the coal pile and depth of required
excavation would complicate implementation. The presence of shallow groundwater will limit the
amount of soils that can be excavated. Enhanced vacuum extraction under Alternatives 5 and 6 would
be more complex to design but easier to implement than complete soil excavation and ex situ soil
remediation technologies. For Alternative 4, pilot studies are required to determine the best design
for the groundwater extraction and treatment system. Because air stripping is negatively affected by
cold temperatures, UV oxidation is favored for treatment of contaminated groundwater.
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6.2.2.5 Costs
Based on the information available at the time the alternatives were developed, the estimated costs for
each alternative evaluated for the CSV source area are in Table 6-2.
6.2.3 Modifying Criteria
6.2 J.I State Acceptance
ADEC has been involved with the development of remedial alternatives for OU-4 and agrees with the
selected remedy for the CSY source area.
6.2.3.2 Community Acceptance
No comments regarding remedial action at OU-4 were; received during the comment period. This
may indicate that there is no opposition to any of the preferred alternatives. The Responsiveness
Summary, Appendix B to this document, provides the background of community involvement
activities conducted in association with OU-4.
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Page 1 of 1
Table 6-1
PRESENT-WORTH COSTS8
FOR REMEDIAL ALTERNATIVES
LANDFILL SOURCE AREA
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Description
Present-Worth
Capital Cost
Present-Worth
Operation and
Maintenance
Cost
Total
Present-
Worth Cost
Landfill Source Area
Alternative 1: No action.
Alternative 2: Institutional Controls, Natural Attenuation, and
Groundwater Monitoring.
Alternatives: Phased approach. Phase 1: Capping, security
fencing, and monitoring.
Alternative 4: Groundwater pump and treat (UV oxidation)
security fencing, and monitoring.
Alternative 5: Landfill capping, security fencing, groundwater
pump and treat (UV oxidation) and monitoring.
$0
$82,000
$476,000
$1,319,000
$1,709,000
$0
$1,009,000
$1,144,000
$7,046,000
$4,324,000
$0
$1,091,000
$1,620,000
$8,365,000
$6,033,000
a These costs are estimated. Actual costs are likely to be within +50% to -30% of the table values. Present worth is
based on a 7% discount rate over the life of the project.
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Page 1 of 1
Table 6-2
PRESENT-WORTH COSTS8
FOR REMEDIAL ALTERNATIVES
COAL STORAGE YARD SOURCE AREA
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
Description
Present-Worth
Capital Cost
Present-Worth
Operation and
Maintenance
Cost
Total
Present-
Worth Cost
Coal Storage Yard Source Area
Alternative 1: No action.
Alternative 2: Institutional Controls, Natural Attenuation, and
Groundwater Monitoring.
Alternative 3: Ex situ low-temperature thermal desorption of
contaminated soils, natural attenuation, and monitoring.
Alternative 4: Ex situ low-temperature thermal desorption of
contaminated soils, groundwater pump and treat (UV
oxidation), monitoring and security fencing.
Alternative 5: Enhanced vacuum extraction of contaminated
soils, natural attenuation, groundwater monitoring, and
security fencing.
Alternative 6: Enhanced vacuum extraction of contaminated
soils, treatment of groundwater via air sparging, monitoring,
and security fencing.
$0
$53,000
$126,000
$1,114,000
$153,000
$364,000
$0
$902,000
$857,000
$1,999,000
$893,000
$1,180,000
$0
$955,000
$983,000
$3,113,000
$1,046,000
$1,544,000
a These costs are estimated. Actual costs are likely to be within +50% to -30% of the table values. Present worth is
based on a 7% discount rate over the life of the project.
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7.0 SELECTED REMEDIES
7.1 LANDFILL SOURCE AREA
The selected remedy for groundwater contamination at the Landfill source area is Alternative 3
because it best meets the nine CERCLA criteria. Alternative 3 includes a phased approach, with
Phase 1 being capping of the older, inactive portion of the Landfill, with natural attenuation,
monitoring/evaluation of groundwater, and institutional controls. Source control through capping of
the older, inactive portion of the Landfill is considered more cost-effective and protective than
additional investigation. Historical records indicate that the older area of the Landfill contains a
significant portion of chemicals contributing to groundwater contamination. It is anticipated that the
capping will result in decreased percolation of rainwater and snowmelt through the Landfill lifts and
will result in decreased Landfill leachate entering the groundwater. Existing contaminants in the
groundwater would attenuate through natural processes. Groundwater downgradient of the Landfill
will be closely monitored in order to assess the natural attenuation process under Phase 1 of this
alternative. If significant contamination is persistent, the need for an active groundwater treatment
system will be evaluated and implemented, if necessary, under Phase 2 of this alternative.
Alternative 3 is believed to be the most cost-effective option for control of Landfill leachate
generation to achieve adequate protection of human health and the environment and ARARs. Landfill
capping will minimize additional leachate reaching the groundwater, reduce contaminant movement,
and achieve groundwater MCLs in a shorter time frame. Modeling estimates used to project cleanup
times for Alternative 3 were based on estimated contaminant loading rates to the groundwater. Under
Alternative 3, the 70 years to achieve RAOs is considered a reasonable time frame. This protection is
not provided under Alternative 2. Additionally, Alternative 2 does not meet State ARARs for solid
waste. It was determined that protection of human health and the environment is attainable without
the use of aggressive groundwater treatment because institutional controls will provide protection until
MCLs are achieved at this source area. However, in the event that landfill capping does not result in
the expected decreases in groundwater contamination, Phase 2 of the selected alternative requires
evaluation and potential implementation of an active groundwater treatment system.
7.1.1 Major Components of the Selected Remedy
• Capping with a minimum of 2 feet of native soil of the approximately
8 acres of the inactive portion of the Landfill to achieve a permeability
no greater than 10~5 cm/sec;
• The cap would maintain native vegetative growth or grasses and
promote natural drainage to prevent ponding and erosion;
• Based on the historical landfilling operations, a methane gas collection
system is not anticipated; however, the need for a gas collection
system will be considered during the Remedial Design;
• Achieving RAOs for groundwater would be through natural
attenuation;
• Monitoring groundwater downgradient of the Landfill and evaluating
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results to determine the effectiveness of the capping and natural
attenuation with respect to RAOs (see Table 7-1); and
• Maintaining institutional controls restricting access to and development
at the site as long as hazardous substances remain onsite at levels that
preclude unrestricted use.
The goal of this remedial action is to restore groundwater to its beneficial use, which is, at this site, a
potential drinking water aquifer. The point of compliance for achieving RAOs will be at wells
downgradient of the Landfill. In the event that it is found through monitoring that natural attenuation
of groundwater is not progressing as expected, or that there is not a significant reduction in leachate,
Phase 2 of this alternative, which calls for evaluation and implementation of an active groundwater
treatment system, would be initiated. Adequate natural attenuation would be measured by comparing
contaminant levels with historical data and MCLs. Effectiveness of Phase 1 will be evaluated during
the five year review.
Based on information obtained during the RI and on careful analysis of all remedial alternatives, the
Army, EPA, and ADEC believe that the selected remedy would be able to achieve this goal.
7.2 COAL STORAGE YARD SOURCE AREA
Alternative 6 is the preferred alternative for the CSV source area because it best meets the nine
CERCLA criteria presented in Section 6. This alternative involves in-place treatment of soils via
vacuum extraction enhanced by steam injection and bioventing; in-place, on-site treatment of
groundwater via air sparging; groundwater monitoring/evaluation; and institutional controls.
Alternative 6 is expected to achieve overall protection of human health and the environment and to
meet ARARs through active treatment of both soil and groundwater (see Table 7-2). This alternative
protects the downgradient drinking water supply wells by treating and controlling the source of
contamination and is viewed as being an effective and permanent solution to contamination at the
CSY.
After a thorough assessment of the applicable alternatives for the CSY source area, taking
groundwater risks, cleanup times, and cost into consideration, it was determined that protection of
human health and the environment is best attained through active in-place treatment of soils and
groundwater. This alternative is believed to provide the best balance of criteria among the
alternatives evaluated.
7.2.1 Major Components of the Selected Remedy
• In situ treatment of groundwater via air sparging to remove VOCs,
thereby attaining state and federal drinking water standards. Air
sparging wells will be placed in areas of highest contamination;
• In situ treatment of soils via soil vapor extraction to prevent
contaminated soils from acting as an ongoing source of contamination
to groundwater. Soil vapor extraction wells will be placed in areas of
highest contamination and operated until groundwater MCLs are
achieved;
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• The treatment system will be evaluated and modified as necessary to
optimize effectiveness in achieving RAOs;
• Duration of treatment system operation is estimated to be nine years to
meet ADEC soil cleanup goals and federal MCLs. A combination of
groundwater monitoring and off-gas measurements will be used to
determine attainment of RAOs;
• After active treatment achieves MCLs, natural attenuation will be
relied on to achieve AWQS;
• Monitoring of the nested downgradient wells to ensure protection of
Post drinking water supply wells during remedial action; and
• Maintaining institutional controls, including restricted access and well
development restrictions, as long as hazardous substances remain on
site at levels that preclude unrestricted use. Restrictions on
groundwater will be implemented until contaminant levels are below
federal MCLs and AWQS.
The goal of this remedial action is to restore groundwater to its beneficial use, which is, at this site, a
drinking water aquifer. The point of compliance for groundwater will be at the treatment system
wells. Based on information obtained during the RI and on careful analysis of all remedial
alternatives, the Army, EPA, and ADEC believe that the selected remedy would be able to achieve
this goal.
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Page 1 of 1
Table 7-1
CHEMICAL-SPECIFIC CLEANUP GOALS FOR GROUNDWATER
LANDFILL SOURCE AREA
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
CLEANUP GOALS FOR GROUNDWATER
Analyte
ARARs
Federal MCL
Alaska Drinking
Water Standards
(state MCLs)
Alaska
State
Water Quality
Standards
TBCs
Site RA RBC
HI
w-4
Site-Specific
Groundwater*
Background
Corpsb
Remedial'
Action
Objective
Maximum
Detected
Concentration
Site
Cleanup
Goal
Organks (/ig/L)
Benzene
cis-1 ,2-Dichloroethene
1 , 1 ,2,2-Tetrachloroethane
1 , 1 ,2-TrichIoroethane
Trichloroethene
Vinyl chloride
bis(2-Ethylhexyl)phthalate
5
70
—
5
5
2
6
5
70
—
—
5
2
6
5
—
2,400
9,400
5
2
—
—
—
—
—
—
—
260
—
—
35
—
—
—
220
ND
ND
ND
ND
ND
ND
ND
5
70
5.2
5
5
2
6
6.3
150
1,300
10
180
1.3
620
5
70
5.2'
5
5
2
6
a Site-specific background groundwater concentration.
Background concentrations from Corps-recommended background value for Fort Wainwright.
c Groundwater remediation goals are based on Region 3 1 X 10"4 RBCs. There is no federal or state MCL for this contaminant.
Key:
— = Value not established.
ARAR = Applicable or relevant and appropriate requirement.
Corps = United States Army Corps of Engineers, Alaska District.
HI = Hazard index.
/ig/L = Micrograms per liter.
MCL = Maximum contaminant level.
ND = Not detected.
RA = Human health risk assessment.
RBC = Risk-based concentration.
TBC = To be considered.
TRPH = Total recoverable petroleum hydrocarbon.
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Page 1 of 2
00
Table 7-2
CHEMICAL-SPECIFIC CLEANUP GOALS FOR GROUNDWATER AND SOIL
COAL STORAGE YARD SOURCE AREA
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
CLEANUP GOALS FOR GROUNDWATER
Analyte
ARARS
Federal
MCL
Alaska
Drinking Water
Standards
(state MCL)
Alaska State
Water Quality
Standards
TBCs
Site RA RBC
HI
10-4
Site-Specific
Groundwater*
Background
Corpsb
Remedial
Action
Objective6
Maximum
Detected
Concentration
Site
Cleanup
Goal
Cleanup Goals for Groundwater
Organics Otg/L)
Benzene
bis(2-Ethylhexyl)phthalate
Trichloroethene
Toluene
5
6
5
1,000
5
6
5
1,000
5
—
5
10d
—
—
—
—
250
220
—
—
NA
2"
NA
NA
5
6
5
1,000
800
110
56
1
5
6
5
1,000
Key at end of table.
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Page 2 of 2
VO
Table 7-2
CHEMICAL-SPECIFIC CLEANUP GOALS FOR GROUNDWATER AND SOIL
COAL STORAGE YARD SOURCE AREA
OPERABLE UNIT 4
FORT WAINWRIGHT, ALASKA
CLEANUP GOALS FOR SOIL
COAL STORAGE YARD SCORE
Matrix Score = 39
BTEX = 15 mg/kg
Benzene = 0.5 mg/kg
VPH = 100 mg/kg
EPH = 200 mg/kg
Level Ae >40
Level B 27-40
Level C 21-26
Level D <20
ADEC Cleanup Level (mg/kg)
Diesel
Diesel-range
petroleum
hydrocarbons
(EPH)
100
200
1,000
2,000
Gasoline/Unknown
Gasoline-range
petroleum
hydrocarbons
(VPH)
50
100
500
1,000
Benzene
0.1
0.5
0.5
0.5
BTEX
10
15
50
100
a Site-specific background groundwater concentration.
" Background concentrations from Corps-recommended background value for Fort Wainwright.
c Groundwater remedial goals are based on federal and state MCLs for organic contaminants in public water supply systems (40 CFR 141.147 and 18 AAC 80).
d 18 AAC 70, Water Quality Standards. The regulatory level for BTEX is 10 ng/L.
e Level A cleanup goal is applied to the total matrix score of 39 due to the soil acting as an ongoing source of contamination to groundwater.
Key:
AAC
ADEC
ARAR
BTEX
CFR
CORP
mg/kg
MCL
NA
RA
RBC
TBC
Level has not been established.
Alaska Administrative Code.
Alaska Department of Environmental Conservation.
Applicable or relevant and appropriate requirement.
Benzene, toluene, ethylbenzene, xylene.
Code of Federal Regulations.
United States Army Corps of Engineers, Alaska District.
Micrograms per liter.
Milligram per kilogram.
Maximum contaminant level.
Not available.
Human Health Risk Assessment.
Risk-based concentrations.
To be considered.
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8.0 STATUTORY DETERMINATIONS
The primary responsibility of the Army, EPA, and ADEC under their legal CERCLA authority is to
select remedial actions that are protective of human health and the environment. In addition, Section
121 of CERCLA, as amended by SARA, provides several statutory requirements and preferences.
The selected remedy must be cost-effective and utilize permanent treatment technologies or resource
recovery technologies to the extent practicable. The statute also contains a preference for remedies
that permanently or significantly reduce the volume, toxicity, or mobility of hazardous substances
through treatment. Lastly, CERCLA requires that the selected remedial action for each source area
must comply with ARARs established under federal and state environmental laws, unless a waiver is
granted.
8.1 PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT
The selected alternatives for the Landfill and CSV source areas will provide long-term protection of
human health and the environment and satisfy the requirements of Section 121 of CERCLA.
8.1.1 Landfill Source Area
The selected remedy will provide long-term protection of human health and the environment in two
ways. Leachate from Landfill materials will be reduced by placing a protective cover over the older
portion of the Landfill. Contaminant concentrations currently in the groundwater will attenuate by
natural processes over time. Groundwater monitoring/evaluation will continue until such time as
attenuation has been completed or implementation of Phase 2 (groundwater treatment) is under way.
8.1.2 Coal Storage Yard Source Area
The selected remedy will provide long-term protection of human health and the environment by
removing the contamination from soils and groundwater through installation of a vapor extraction/air
sparging system. The remedy will eliminate the potential exposure routes and minimize the
possibility of contamination migrating to drinking water sources. Groundwater monitoring/evaluation
will be completed to assess contaminant plume movement and concentrations.
8.2 COMPLIANCE WITH APPLICABLE OR RELEVANT AND APPROPRIATE
REQUIREMENTS AND TO-BE-CONSIDERED GUIDANCE
The selected remedy for each source area will comply with all ARARs of federal and state
environmental and public health laws. These include compliance with all the location-, chemical-,
and action-specific ARARs listed below. No other waiver of any ARAR is being sought or invoked
for any component of the selected remedies.
8.2.1 Applicable or Relevant and Appropriate Description
An ARAR may be either "applicable" or "relevant and appropriate." Applicable requirements are
those substantive environmental protection standards, criteria, or limitations, promulgated under
federal or state law, which specifically address a hazardous substance, remedial action, location, or
other circumstance at a CERCLA site. Relevant and appropriate requirements are those substantive
environmental protection requirements, promulgated under federal and state law, which while not
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legally applicable to the circumstances at CERCLA site, address situations sufficiently similar to those
encountered at the CERCLA site so that their use is well-suited to the particular site. The three types
of ARARs are described below:
• Chemical-specific ARARs are usually health- or risk-based numerical
values or methodologies that establish an acceptable amount or
concentration of a chemical in the ambient environment;
• Action-specific ARARs are usually technology- or activity-based
requirements for remedial actions; and
• Location-specific ARARs are restrictions placed on the concentration
of hazardous substances or the conduct of activity solely because they
occur in special locations.
To-be-considered (TBC) requirements are nonpromulgated federal or state standards or guidance
documents that are to be used on an "as appropriate" basis in developing cleanup standards. Because
they are not promulgated or enforceable, they do not have the same status as ARARs and are not
considered required cleanup standards. They generally fall into three categories:
• Health effects information with a high degree of credibility;
• Technical information on how to perform or evaluate site
investigations or response actions; and
• State or federal agency policy documents.
8.2.2 Chemical-Specific Applicable or Relevant and Appropriate Requirement
• Federal Safe Drinking Water Act 40 Code of Federal Regulations
[CFR] 141) and Alaska Drinking Water Regulation (18 AAC 80):
The MCL and nonzero MCL goals established under the Safe
Drinking Water Act are relevant and appropriate requirements for
groundwater that is a potential drinking water source.
• AWQS (18 AAC 70): Alaska Water Quality Standards for Protection
of Class (1)(A) Water Supply, Class (1)(B) Water Recreation, and
Class (1) Aquatic Life and Wildlife (18 AAC 70) are applicable to
both source areas. Many of the constituents of groundwater regulated
by AWQS are identical to MCLs in Drinking Water Standards.
• Alaska Oil Pollution Regulation (18 AAC 75): Alaska Oil Pollution
regulations are applicable and responsible parties required to clean up
oil or hazardous releases. Soil cleanup remediation will be designed
to protect groundwater in accordance with State of Alaska Drinking
Water Standards.
• Alaska Regulations for Leaking Underground Storage Tanks (18 AAC
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78): The State of Alaska cleanup requirements for contaminated soils
from leaking underground storage tanks to protect groundwater are
relevant and appropriate for the CSV.
• Alaska Solid Waste Management Regulations (18 AAC 60): The
Alaska Solid Waste Management regulations are applicable to the
Landfill.
8.2.3 Location-Specific Applicable or Relevant and Appropriate Requirement
• Clean Water Act Section 404: Section 404 of the Clean Water Act,
which is implemented by EPA and the Army through regulations
found in 40 CFR 230 and 33 CFR 320 to 330, prohibits the discharge
of dredged or fill materials into Waters of the U.S. without a permit.
This statute is relevant and appropriate to the protection of wetlands
adjacent to the Landfill and CSV source areas.
8.2.4 Action-Specific Applicable or Relevant and Appropriate Requirement
• RCRA Solid Waste Landfill Closure Criteria (40 CFR 258.60): 40
CFR 258.60 includes relevant and appropriate regulations pertaining
to installation of a cap on a solid waste landfill. Specifically,
according to 40 CFR 258.60 (1), if a final cover system is installed at
Fort Wainwright, it is required to have a permeability no greater than
1 x 10'5 cm/sec. Additionally, 40 CFR 258.60 (2)(3) specifies that the
thickness of an infiltration and erosion layer must be a minimum of 18
and 6 inches of earthen material, respectively, and that the erosion
layer must be capable of sustaining native plant growth; and
• Federal Clean Air Act (42 United States Code 7401), as amended, is
applicable for venting contaminated vapors.
8.2.5 Information To-Be-Considered
The following information TBC will be used as a guideline when implementing the selected remedy:
• State of Alaska Guidance for Storage, Remediation, and Disposal of
Non-UST Petroleum Contaminated Soils (July 29, 1991) for the CSY;
and
• State of Alaska Interim Guidance for Surface and Groundwater
Cleanup Levels (September 26, 1990) for the CSY.
8.3 COST EFFECTIVENESS
The selected remedy for each source area is cost-effective when the degree of protectiveness it
provides is compared to the overall protectiveness provided by the other treatment alternatives.
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8.4 UTILIZATION OF PERMANENT SOLUTIONS AND ALTERNATIVE TREATMENT
TECHNOLOGIES OR RESOURCE RECOVERY TECHNOLOGIES TO THE
MAXIMUM EXTENT PRACTICABLE
The United States Army, State of Alaska, and EPA have determined that the selected remedies
represent the maximum extent to which permanent solutions and treatment technologies can be used in
a cost-effective manner at the OU-4 source areas. Of those alternatives that protect human health and
the environment and comply with ARARs, the Army, State of Alaska, and EPA have determined that
the selected remedies provide the best balance of trade-offs in terms of long-term effectiveness and
permanence; reduction of toxicity, mobility, or volume through treatment; short-term effectiveness;
implementability; cost; and the statutory preference for treatment as a principal element in considering
state and community acceptance.
8.5 PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT
The selected remedy for the CSV satisfies the statutory preference for treatment for both groundwater
and soil. Phase 1 of the Landfill remedy does not actively treat groundwater; however, Phase 2
would use groundwater treatment as a principal element if deemed necessary.
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9.0 DOCUMENTATION OF SIGNIFICANT CHANGES
The selected remedy for the Landfill and CSY source areas is the same preferred alternative for each
area presented in the Proposed Plan. No changes in the components of the preferred alternative have
been made.
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APPENDIX A
ARMY DECISION DOCUMENT FOR THE FIRE TRAINING PITS
105
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DEPARTMENT OF THE ARMY
HEADQUARTERS, U.S. ARMY ALASKA
600 RICHARDSON DRIVE # 5000
FORT RICHARDSON, ALASKA 99505-5000
REPLY TO
ATTENTION OF:
DECISION DOCUMENT
for
FIRE TRAINING PITS, OPERABLE UNIT 4
1. PURPOSE OF REMOVAL ACTION:
a. This decision document describes the removal action for the Fire
Training Pits (FTPs) 3 A and 3B Source Area, Operable Unit 4, at Fort
Wainwright. This removal action has been chosen in accordance with
Comprehensive Environmental Response, Compensation, Liability Act
(CERCLA) as amended by Superfund Amendment Reauthorization Act (SARA),
the National Contingency Plan (NCP), Resource Conservation and Recovery Act
(RCRA), and Army Regulation 200-1, as applicable.
b. The FTPs at Fort Wainwright include two wide, shallow pits
designated as FTP-3A and FTP-3B, and a 2-foot depression area northwest of
FTP-3B. The FTPs are located in the main cantonment area west of the
ammunition storage area, as shown in Figure 1-4. The FTPs Source Area was
utilized by Fort Wainwright's fire department and rescue crews from
approximately 1970 to 1988 for training in fire extinguishing exercises. The
exercises included soaking the soils of the pits with water, filling the pits with
petroleum products (i.e., fuels, brake fluid, waste oil, and/or solvents), igniting
the flammable mixture, and extinguishing the resultant fire. Approximately
1,500 to 2,300 gallons of flammable liquids were burned each year in the unlined
pits. Soil investigations at the FTPs Source Area revealed petroleum as the only
contaminant requiring remediation, specifically diesel and Diesel Range
Organics (DRO) in the surface soils and Total Recoverable Petroleum
Hydrocarbons (TRPH) in both the surface and subsurface soils. Volatile Organic
Compounds (VOC), Semi-Volatile Organic Compounds, pesticide, and
dioxin/furan contaminants were found in the soils below action levels.
Inorganics are naturally occurring at Fort Wainwright and were also found in the
soils. Some of the inorganics, specifically Arsenic and Selenium, were found to
have higher concentrations in isolated locations at the FTPs Source Area. These
isolated hits were determined to be natural occurrences since no former or
current practice or source could be found to cause these high inorganic
concentration levels. Investigations on the groundwater at the FTPs Source Area
revealed one VOC, Trichloroethylene, detected in only one groundwater sample.
Subsequent groundwater sampling revealed no VOC contaminants. Semi-VOCs
and petroleum constituents were detected in the groundwater below federal and
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APVR-RPW-EV
Decision Document for Fire Training Pits, Operable Unit 4
state maximum contaminant levels. Based on the results of the soil and
groundwater investigations at the FTPs Source Area, a removal action of the
petroleum contaminated soils will be conducted. This action will remove the
source and eliminate the risk to human health and the environment.
c. This decision document was developed by the Fort Wainwright,
Directorate of Public Works with support from the State of Alaska Department of
Environmental Conservation (ADEC) and the U.S. Environmental Protection
Agency (EPA). Regulatory agency concurrence, i.e., ADEC and the EPA, with
this Decision Document removal action can be found in the Record of Decision
for Operable Unit 4, Fort Wainwright.
2. SUMMARY OF SITE RISK:
a. The primary source of contamination at the FTPs Source Area is
residual material from past burning operations. Contaminant groups detected
during the Remedial Investigation included inorganics (i.e., metals), VOCs,
petroleum hydrocarbons, dioxins/furans, and pesticides; however, petroleum
contaminants, specifically diesel and DRO in the surface soils and TRPH in the
surface and subsurface soils, are the only contaminants that require remediation.
The baseline human health risk assessment estimated the potential excess
lifetime cancer risks and hazard indices for current landuse conditions at the
FTPs Source Area to be within or below the regulatory benchmarks, defined by
the EPA Superfund program. These estimated cancer and noncancer risks were
low because of the low concentrations of contaminants detected and because
there were no current, complete exposure pathways for groundwater. The only
risks that were encountered during the human health risk assessment were those
associated with future residential use of groundwater. The ecological risk
assessment conducted at the FTPs Source Area revealed adverse effects to small
mammals and robins from the isolated hits of inorganics found in the soils at the
FTPs Source Area. The Remedial Investigation determined these hits to be
natural occurrences, since no former or current practice or source could be found
to cause the high inorganic concentration levels. For this reason, the inorganics
are not identified as a contaminant requiring remediation and are not addressed
in the removal action.
b. The migration pathways that affect human health and the environment
at the FTPs Source Area are surface water migration and groundwater flow and
discharge. Surface soil contamination (i.e., DRO, diesel, and TRPH), which was
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APVR-RPW-EV
Decision Document for Fire Training Pits, Operable Unit 4
identified within both pits during the Remedial Investigation, was found in
several isolated areas of drainage ditches and wetlands due to surface water
migration. Subsurface soil contamination (i.e., TRPH), which was identified as
not being widespread but isolated under both pits and a depression area
northwest of FTP-3B during the Remedial Investigation, extends from the
ground surface, through the vadose zone, to the groundwater and soil interface.
Presently, groundwater contaminants throughout the FTPs Source Area fall
below federal or state maximum contaminant levels. However, soil contaminant
levels pose a threat to the groundwater. If the source of petroleum
contamination is not removed from the soils at the FTPs Source Area, the soils
will continue to contribute contamination to the groundwater, via infiltration
and percolation, and potential cancer and noncancer risks for future residential
use of groundwater will exceed the regulatory benchmarks. Risks will remain at
the FTPs Source Area if no action is taken.
3. SUMMARY OF REMOVAL ACTION:
a. The removal action for the FTP Source Area is summarized below and
described in the Feasibility Study Final Report, Operable Unit 4, Fort
Wainwright, Alaska, Ecology and Environment, Inc., dated November 1995.
REMOVAL ACTION COST($)
Ex-situ low-temperature thermal desorption of contaminated soils $5,000
b. Petroleum contaminants, specifically diesel and diesel range organics
in the surface soils and total recoverable petroleum hydrocarbons in the surface
and subsurface soils, are the only contaminants at the FTP Source Area that
require remediation. In order to minimize continued contamination of the
impacted media, the Army has opted to use removal authority, as specified in
the NCP, to excavate and remediate (via low-temperature thermal desorption)
the petroleum-contaminated soils. The contract to complete the removal action
was awarded and is projected to occur in the spring of 1996. It is anticipated that
the removal at the FTP Source Area will constitute final action for this source of
soil contamination.
c. This site is currently listed under the Three Party Agreement between
the Department of the Army, ADEC, and the EPA under Operable Unit 4 of the
Federal Facilities Agreement for Fort Wainwright. Failure to take corrective
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APVR-RPW-EV
Decision Document for Fire Training Pits, Operable Unit 4
action, as required by the agreement, may result in penalties stipulated in the
agreement.
4. PUBLIC/COMMUNITY INVOLVEMENT:
a. It is DOD and Army policy to involve the local community as early as
possible and throughout the Removal process at an installation. To accomplish
this, the FTPs Source Area has complied with the public participation
requirements of CERCLA/SARA (Sections 113 (K) (2) (A) and 117). Information
regarding the history, operational practices, and removal action for the FTPs
Source Area was disseminated to the public through the following mechanisms:
• Proposed Plan for Remedial Action at Operable Unit 4
• Fort Wainwright Superfund Update Newsletter
• Environmental Restoration Newsletter
• Operable Unit 4 Public Meeting
b. Future community involvement at the FTPs Source Area consists of
updating the Administrative Record for Fort Wainwright once the excavation
and remediation of the contaminated soils is complete. The Administrative
Record is open to the public and located at three Information Repositories in
Fairbanks.
5. DECLARATION: The selected remedy is protective of human health and the
environment, attains Federal and State requirements that are applicable or
relevant and appropriate to this removal action, and is cost effective. This
remedy satisfies the statutory preference for remedies that employ treatment that
reduces toxicity, mobility or volume as a principal element and utilizes
permanent solutions and alternative treatment technologies to the maximum
extent practicable. Because this remedy will not result in hazardous substances
remaining on-site above levels that allow for unlimited use and unrestricted
exposure, the five-year review will not apply to this action.
INETH W. SIMPSON
Maljor General, USA
Commanding
109
-------
FORT WAINWRIGHT KEY PUN
LEGEND
;?=%=i ROAD
— ... — DRAINAGE DITCH
•*• WETUND
APPROXIMATE SCALE IN FEET
600 1.200
[jrecoloEJ tnd cnTiromneot, Inc.
^HtmMknrf JftdAti h 9m U*vmfit
FIRE
FAIRBANKS
SZE
B
U.S. ARMY
ENGINEER DISTRICT. ALASKA
CORPS OF ENGINEERS
ANCHORAGE. ALASKA
Figure 1-4
TRAINING PITS AREA
LOCATION MAP
OPERABLE UNIT 4
ALASKA
JOB. NO.
JV8040
RLE NO.
JV8S013B
DATE:
10-06-95
PLATE
-------
-------
APPENDIX B
RESPONSIVENESS SUMMARY
111
-------
-------
RESPONSIVENESS SUMMARY FOR THE RECORD OF DECISION FOR
REMEDIAL ACTION AT OPERABLE UNIT 4, FORT WAINWRIGHT, ALASKA
OVERVIEW
The United States Army (Army), Alaska, United States Environmental Protection Agency, and the
Alaska Department of Environmental Conservation, collectively referred to as "the Agencies,"
distributed a Proposed Plan for remedial action at Operable Unit 4 (OU-4), Fort Wainwright, Alaska.
OU-4 comprises three source areas: the Landfill; the Coal Storage Yard (CSY); and the Fire
Training Pits (FTPs).
The Proposed Plan identified preferred remedial alternatives for two of the three source areas within
OU-4. The third source area, the FTP area, was not considered for remedial action in the Proposed
Plan. The contaminants at this source area consist of petroleum products and will be addressed
through an Army removal action that includes excavation and disposal.
The major components of the remedial alternatives for the Landfill are a phased approach:
Phase 1:
• Involving capping the older, inactive portion of the Landfill,
• Natural attenuation,
• Groundwater monitoring, and
• Institutional controls.
Phase 2:
• Evaluation and implementation of active groundwater treatment
systems, if necessary.
The major components of the remedial alternatives for the CSY are:
• In-place treatment of soils via vacuum extraction enhanced by steam
injection and bioventing;
• In-place, on-site treatment of groundwater via air sparging;
• Groundwater monitoring; and
• Institutional controls.
No formal comments regarding the Proposed Plan for the OU-4 remedial action were submitted
during the public comment period.
112
-------
BACKGROUND OF COMMUNITY INVOLVEMENT
The public was encouraged to participate in the selection of the final remedies for OU-4 during a
public comment period from October 10 to November 10, 1995. The Fort Wainwright Proposed
Plan for Remedial Action at Operable Unit 4 presented 11 combinations of options considered by the
Agencies to address contamination in soil and groundwater at OU-4. The Proposed Plan was released
to the public on October 10, 1995, and copies were sent to all known interested parties, including
elected officials and concerned citizens. Informational Fact Sheets, dated March and September 1995,
which provided information about the Army's entire cleanup program at Fort Wainwright, were
mailed to the addresses on the same mailing list.
The Proposed Plan summarized available information regarding the OU. Additional materials were
placed into two information repositories, one at the Noel Wien Library in Fairbanks and the other at
the Fort Wainwright Post Library. An Administrative Record, including all items placed in the
information repositories and other documents used in the selection of the remedial actions, was
established in Building 3023 on Fort Wainwright. The public was welcome to inspect materials
available in the Administrative Record and the information repositories during business hours.
Interested citizens were invited to comment on the Proposed Plan and the remedy selection process by
mailing comments to the Fort Wainwright project manager, by calling a toll-free telephone number to
record a comment, or by attending and commenting at a public meeting on October 17, 1995, at the
Carlson Center in Fairbanks.
Basewide community relations activities conducted for Fort Wainwright, which includes OU-4, have
included:
• July 1992—Community interviews with local officials and interested
parties;
• April 1993—Preparation of the Community Relations Plan;
• July 1993—Distribution of an informational Fact Sheet covering all
OUs at Fort Wainwright;
• July 22, 1993—An informational public meeting covering all OUs;
and
• April 22, 1994—Establishment of information repositories at the Noel
Wien Library and the Fort Wainwright Post Library and the
Administrative Record at Building 3023 on Fort Wainwright.
Community relations activities specifically conducted for OU-4 included:
• October 4, 8, 11, 15, 16, and 17, 1995—Display advertisement
announcing the public meeting in the Fairbanks Daily News-Miner;
• October 10, 1995—Distribution of the Proposed Plan for final
remedial action at OU-4;
113
-------
October 10 to November 10, 1995—Thirty-day public comment
period. No extension was requested;
October 10 to November 10, 1995—Toll-free telephone number for
citizens to provide comments during the public comment period. The
toll-free telephone number was advertised in the Proposed Plan and
the newspaper display advertisement that announced the public
meeting; and
October 17, 1995—Public meeting at the Carlson Center to provide
information, a forum for questions and answers, and an opportunity
for public comment regarding OU-4.
SUMMARY OF COMMENTS RECEIVED DURING THE PUBLIC COMMENT PERIOD
No comments were received during the public comment period.
114
-------
-------
APPENDIX C
COST CALCULATIONS
LANDFILL AND COAL STORAGE YARD SOURCE AREAS
115
-------
-------
Table*
LIFE CYCLE COST
10/4/95 10:39
Project Name: OU4
Project Number: JV8000
Installation .& Location: OU4 - Landfill
Alt. No. : 2
Title: Institutional Controls and Groundwater Monitoring-
Natural Attenuation of Groundwater with semi-annual
Monitoring and institutional Controls
Analysis Base Date: Dec 94
Analyis End Date: Dec 94
BOD for Analysis:
Annual Discount Rate: 0.07
Escalation Rate: 0.00
ONE-TIME COSTS
GROUNDWATER MONITORING (25 WELLS @ $200/Well)
1. Monitoring Workplan
INSTITUTIONAL CONTROL:
1. Fencing (2700 LF @ $19.07/LF, plus 2 gates)
(Midpoint)
Years from Cost on
ABD ABD
1 $5,000
$54,000
Discount
Factor
NA
NA
ON
SUBTOTAL P/W
25% INDIRECT
10% CONTINGENCY
TOTAL
Present
Worth on
ABD
$5,000
$54,OOP
$59,000
$14,750
$7,375
$82,000
* The total has been rounded up to the nearest $1,000.
Landfill
Alternative 2
Capital Costs
-------
LIFE CYCLE COST
10/4/95 10:45
Project Name: OU4
Project Number: JV8000
Installation & Location: OU4 - Landfill
Alt. No. : 2
Title: Institutional Controls and Groundwater Monitoring -
Natural Attenuation of Groundwater with Semi-Annual
Monitoring and Institutional Controls
Analysis Base Date: Dec 94
Analyis End Date: Dec 94
BOD for Analysis:
Annual Discount Rule: 0.07
Escalation Rate: 0.00
ANNUAL COSTS
GROUNDWATER MONITORING (25 WELLS @ $2650/WELL):
Equipment Shipping
Sampling Equipment (jars,
Travel Expenses (Air Fare
Field Team (2-Man, 25-hrs
Sample Shipping Costs (20
YEARS FROM ABD
First
Incurred
pump, generat., labels, etc
Per Diem, Rental Car, etc.
@ $160/hr)
Coolers at $75/Cooler)
Sample Analysis (Two Analytes)
7. Quality Assurance Report (0.5-hr per analyt @ $80/hr)
8. Summary Report
9. Investigation Derived Waste Management
10. Administration Costs
INSTITUTIONAL CONTROL:
1. Maintain Fencing
.D: Total
Last Number of
Incurred Payments
1
1
1
1
1
1
1
1
1
1
1
85
85
85
85
85
85
85
85
85
85
15
85
85
85
85
85
85
85
85
85
85
15
Annual
Cost on Discount
ABD
$3,
$3,
$8,
$3,
$26,
$4,
$4,
$8,
$2,
$1,
Present
Worth on
Factor
600
750
030
000
000
250
000
640
000
500
000
14
14
14
14
14
14
14
14
14
14
9.
.24
.24
.24
.24
.24
.24
.24
.24
.24
.24
108
SUBTOTAL P/W
$
$
$
$
$
$
$
$
$
$
$
10% CONTINGENCY
TOTAL
$1,
ABD
8,
53,
43,
113,
42,
373,
56,
66,
113,
35,
$9,
917,
$91,
,009,
544
400
147
920
720
800
960
074
920
600
108
193
719
000
* The total has been rounded up to the nearest $1,000.
Landfill
Alternative 2
Annual Costs
-------
Tab:MJf-
LIFE CYCLE COST
00
10/4/95 10:43
Project Name: OU4
Project Number: JV8000
Installation & Location: OU4 - Landfill
Alt. No. : 3
Title: Phased Approach. Phase 1 - Cap Inactive Portion
of Landfill with Institutional Controls and
Natural Attenuation of Groundwater with Semi-Annual
Monitoring.
ONE-TIME COSTS
LANDFILL CAP:
1. Earthwork (26,000 cy, 2-ft depth @ $6.77/cy)
2. Develop/Restore Soil Borrow Pit (4 acres)
3. Hydraseed Cap (8 acres @ $1694/acre)
4 Gas Collection (6 wells, piping, flare, building)
Analysis Base Date: Dec 94
Analyis End Date: Dec 94
BOD for Analysis:
Annual Discount
Escalation Rate
(Midpoint )
Years from
ABD
1
1
1
1
Rate: 0.07
0 .00
Cost on
ABD
$177 , 000
$61 , 000
$14,000
$35, 000
Present
Discount Worth on
Factor ABD
NA $177,000
NA $61,000
NA $14,000
NA $35,000
INSTITUTIONAL CONTROL:
1 Fencing (2,700 LF @ $19.07/LF, plus 2 gates)
GROUNDWATER MONITORING (25 WELLS @ $200/Well):
1. Monitoring Workplan
$54,000
$5,000
SUBTOTAL P/W
25% INDIRECT
10% CONTINGENCY
TOTAL
NA
NA
$54,000
$5,000
$346,000
$86,500
$43,250
$476,000
* The total has been rounded up to the nearest $1,000.
Landfill
Alternative 3
Capital Costs
-------
Tabl
LIFE CYCLE COST
10/4/95 10:41
Project Name: OU4 Analysis Base Date: Dec 94
Project Number: JV8000 Analyis End Date: Dec 94
Installation & Location: OU4 - Landfill BOD for Analysis:
Alt. No. : 3 . Annual Discount Rate: 0.07
Title: Phased Approach. Phase 1 - Cap Inactive Portion Escalation Rate: 0.00
of Landfill with Institutional Controls and
Natural Attenuation of Groundwater with Semi-Annual
Monitoring
YEARS
ANNUAL COSTS First
FROM ABD: Total
Last Number of
LANDFILL CAP: Incurred Incurred Payments
1.
2.
1
2.
3.
4.
5.
6.
7 .
8.
9.
10.
1
Blower Power (Continuously run @ $0.10/kW-hr)
Misc. Costs (Erosion & Pump Maint., Admin., Monitoring)
GROUNDWATER MONITORING (25 WELLS @ $2650/WELL) :
Equipment Shipping
Sampling Equipment (jars, pump, general., labels, etc.)
Travel Expenses (Air Fare, Per Diem, Rental Car, etc.)
Field Team (2-Man, 25-hrs @ $160/hr)
Sample Shipping Costs (20 Coolers at $75/Cooler)
Sample Analysis (Two Analytes)
Quality Assurance Report (0.5-hr per analyt @ $80/hr)
Summary Report
Investigation Derived Waste Management
Administration Costs
INSTITUTIONAL CONTROL:
Maintain Fencing
1 30
1 30
1 70
1 70
1 70
1 70
1 70
1 70
1 70
1 70
1 70
1 70
1 30
30
30
70
70
70
70
70
70
70
70
70
7 0
30
Annual
Cost on Discount
ABD
$2,
$8,
S3,
$3,
$8,
$3,
$26,
$4,
$4,
$8,
-------
Table"
LIFE CYCLE COST
10/4/95 10:50
Project Name: OU4
Project Number: JV8000
Installation & Location: OU4 - Landfill
Alt. No. : 4
Title: UV Oxidation of Groundwater with Institutional
Controls and Semi-Annual Monitoring
Analysis Base Date: Dec 94
Analyis End Date: Dec 94
BOD for Analysis:
Annual Discount Rate: 0.07
Escalation Rate: 0.00
N)
O
ONE-TIME COSTS
INSTITUTIONAL CONTROLS:
1. Fencing (2,700 LF @ $19.07/LF, plus 2 gates)
GROUNDWATER MONITORING (25 WELLS @ $200/Well):
1. Monitoring Workplan
GROUNDWATER PUMP AND TREAT (UV OXIDATION)
1. Extraction Wells (6 @ 23.5 If @ $100/lf)
2. Extraction Piping (1300 If @ $30/lf)
3. UV Oxidizers (180 kW system)
4. Post UV Filtration for Metals
5. Building (2000 sf @ $60/sf)
6. Electrical (Controllers, switches, contracting)
7. Equipment Installation (unloading, leveling, anchoring)
8. Plumbing/Misc.(Cooling Water, Steam, H2O2 Tank)
9. Furnace/Heat Exchangers
10. Pilot Scale Studies for UV Treatment
(Midpoint)
Years from
ABD
Cost on
ABD
$54,000
$5,000
Discount
Factor
NA
NA
Present
Worth on
ABD
$54,000
$5,000
1
1
1
1
1
1
1
1
1
1
$15, 000
$39,000
$297,000
$100,000
$120, 000
$50,000
$50,000
$75, 000
$3,750
$150,000
SUBTOTAL P/W
25% INDIRECT
10% CONTINGENCY
TOTAL
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
$15, 000
$39, 000
$297, 000
$100,000
$120,000
$50, 000
$50, 000
$75, 000
$3,750
$150,000
$958,750
$239,688
$119,844
$1,319,000
The total has been rounded up to the nearest $1,000.
Landfill
Alternative 4
Capital Costs
-------
to
LIFE CYCLE COST
10/4/95 10:48
Project Name: OU4 Analysis Base Date: Dec 94
Project Number: JV8000 Analyis End Date: Dec 94
Installation & Location: OU4 - Landfill BOD for Analysis:
Alt. No. : 4 . Annual Discount Rate: 0.07
Title: UV Oxidation of Groundwater with Institutional Escalation Rate: 0.00
Controls and Semi-Annual Monitoring
YEARS
ANNUAL COSTS First
FROM ABD: Total
Last Number of
PUMP AND TREAT (UV OXIDATION) : Incurred Incurred Payments
1.
2.
3.
4.
1.
2.
3.
4.
5.
6.
7 .
8.
9.
10
1.
UV Oxidizers (electrical, H2O2)
Extraction Well Pumps (6 - 8 hp pumps)
Sampling (Weekly, 3 sample points @ $180/point)
Metals Filter (filter replacement, consumables)
GROUNDWATER MONITORING (25 WELLS @ $2650/WELL) :
Equipment Shipping
Sampling Equipment (jars, pump, generat . , labels, etc.)
Travel Expenses (Air Fare, Per Diem, Rental Car, etc.)
Field Team (2-Man, 25-hrs @ $160/hr)
Sample Shipping Costs (20 Coolers at $75/Cooler)
Sample Analysis (Two Analytes)
Quality Assurance Report (0.5-hr per analyt @ $80/hr)
Summary Report
Investigation Derived Waste Management
Administration Costs
INSTITUTIONAL CONTROL:
Maintain Fencing
1 25
1 25
1 25
1 25
1 25
1 25
1 25
1 25
1 25
1 25
1 25
1 25
1 25
1 25
1 25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
Annual
Cost on Discount
ABD
$280,
$31,
$28,
$144,
$3,
$3,
$8,
$3,
$26,
$4,
$4,
$8,
$2,
$1,
Present
Worth on
Factor
500
368
080
869
600
750
030
000
000
250
000
640
000
500
000
11
11
11
11
11
11
11
11
11
11
11
11
11
11
11
654
654
654
654
654
654
654
654
654
654
654
654
654
654
654
SUBTOTAL P/W
$3
$1
$
$
$
$
$
$
$
$
$
$
$6
10% CONTINGENCY
TOTAL
$7
ABD
,268,
$365,
$327,
,688,
6,
43,
35,
93,
34,
305,
46,
54,
93,
29,
$11,
,404,
$640,
,046,
947
560
244
297
992
703
312
232
962
918
616
075
232
135
654
879
488
000
* The total has been rounded up to the nearest $1,000.
Landfill
Alternative 4
Annual Costs
-------
Table*
LIFE CYCLE COST
10/4/95 10:54
Project Name: OU4
Project Number: JV8000
Installation & Location: OU4 - Landfill
Alt. No. : 5
Title: Cap Inactive Portion of Landfill, UV Oxidation of
Groundwater with Institutional Controls and
Semi-Annual Monitoring
Analysis Base Date: Dec 94
Analyis End Date: Dec 94
BOD for Analysis:
Annual Discount Rate: 0.07
Escalation Rate.- 0.00
(0
M
ONE-TIME COSTS
LANDFILL CAP:
1. Earthwork (26,000 cy, 2 FT depth @ $6.77/cy)
2. Develop/Restore Soil Borrow Pit (4 acres)
3. Hydraseed Cap (6 acres @ $1694/acre)
4 Gas Collection (6 wells, piping, flare, building)
INSTITUTIONAL CONTROL:
1. Fencing (2,700 LF @ $19.07/LF, plus 2 gates)
GROUNDWATER MONITORING (25 WELLS @ $200/Well):
1. Monitoring Workplan
GROUNDWATER PUMP AND TREAT (UV OXIDATION)
1. Extraction Wells (6 @ 23.5 If @ $100/lf)
2. Extraction Piping (1300 If @ $30/lf)
3. UV Oxidizers (180 kW system)
4. Post UV Filtration for Metals
5. Building (2000 sf @ $60/sf)
6. Electrical (Controllers, switches, contracting)
7. Equipment Installation (unloading, leveling, anchoring)
8. Plumbing/Misc.(Cooling Water, Steam, H2O2 Tank)
9. Furnace/Heat Exchangers
10. Pilot Scale Studies for UV Treatment
(Midpoint)
Years from
ABD
Cost on
ABD
$177,000
$61,000
$11,000
$35,000
$54,000
$5,000
Discount
Factor
NA
NA
NA
NA
NA
NA
Present
Worth on
ABD
$177,000
$61,000
$11,000
$35,000
$54,000
$5,000
1
1
1
1
1
1
1
1
1
1
$15,000
$39,000
$297,000
$100,000
$120,000
$50,000
$50,000
$75,000
$3,750
$150,000
SUBTOTAL P/W
25% INDIRECT
10% CONTINGENCY
TOTAL
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
$15,000
$39,000
$297,000
$100,000
$120,000
$50,000
$50,000
$75,000
$3,750
$150,000
$1,242,750
$310,688
$155,344
$1,709,000
The total has been rounded up to the nearest $1,000.
Landfill
Altnerative 5
Capital Costs
-------
LIFE CYCLE COST
10/4/95 10:52
N)
00
Project Name: OU4 Analysis Base Date: Dec 94
Project Number: JV8000 Analyis End Date: Dec 94
Installation & Location: OU4 - Landfill BOD for Analysis:
Alt. No. : 5 . Annual Discount Rate: 0.07
Title: Cap Inactive Portion of Landfill, UV Oxidation of Escalation Rate: 0.00
Groundwater with Institutional Controls and
Semi-Annual Environmental Monitoring
YEARS
ANNUAL COSTS First
FROM ABD: Total
Last Number of
LANDFILL CAP: Incurred Incurred Payments
1.
2.
1.
2.
3.
4.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
1.
Blower Power (Continuously run @ $0.10/kW-hr)
Misc. Costs (Erosion & Pump Maint., Admin., Monitoring)
PUMP AND TREAT (UV OXIDATION)
UV Oxidizers (electrical, H202)
Extraction Well Pumps (6 - 8 hp pumps)
Sampling (Weekly, 3 sample points @ $180/point)
Metals Filter (filter replacement, consumables)
GROUNDWATER MONITORING (25 WELLS @ $2650/WELL) :
Equipment Shipping
Sampling Equipment (jars, pump, generat . , labels, etc.)
Travel Expenses (Air Fare, Per Diem, Rental Car, etc.)
Field Team (2-Man, 25-hrs @ $160/hr)
Sample Shipping Costs (20 Coolers at $75/Cooler)
Sample Analysis (Two Analytes)
Quality Assurance Report (0.5-hr per analyt @ $80/hr)
Summary Report
Investigation Derived Waste Management
Administration Costs
INSTITUTIONAL CONTROL:
Maintain Fencing
1 10
1 10
1 10
1 10
1 10
1 10
1 10
1 10
1 10
1 10
1 10
1 10
1 10
1 10
1 10
1 10
1 10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
Annual
Cost on Discount
ABD
$2,
$8,
$280,
$31,
$28,
$144,
$3,
$3,
$8.
$3,
$26,
$4,
$4,
$8,
$2,
$1 ,
Present
Worth on
Factor
000
000
500
368
080
869
600
750
030
000
000
250
000
640
000
500
000
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
7
024
024
024
024
024
024
024
024
024
024
024
024
024
024
024
024
024
SUBTOTAL P/W
$
$
$ 1
$
$
$ 1
$
$
$
$
$
$
$
$
$
$
$3
10% CONTINGENCY
TOTAL
$4
ABD
14,
56,
, 970,
220,
197,
, 017,
4,
26,
21,
56,
21,
184,
28,
32,
56,
17,
$7,
, 930,
$393,
, 324,
048
192
232
327
234
556
214
340
283
192
072
380
096
591
192
560
024
534
053
000
* The total has been rounded up to the nearest $1,000.
Landfill
Alternative 5
Annual Costs
-------
TableTW
LIFE CYCLE COST
10/4/95 10:10
Project Name: OU4
Project Number: JV8000
Installation .& Location: OU4 - Coal Storage Yard
Alt. No. : 2
Title: Institutional Controls and Groundwater Monitoring-
Natural Attenuation of Groundwater with Semi-Annual
Monitoring and Institutional Controls
Analysis Base Date: Dec 94
Analyis End Date: Dec 94
BOD for Analysis:
Annual Discount Rate: 0.07
Escalation Rate: 0.00
ONE-TIME COSTS
GROUNDWATER MONITORING
1. Monitoring Workplan
(25 WELLS @ $200/Well):
INSTITUTIONAL CONTROL:
1. Fencing ($19.07/LF for 1600-LF and 2 Gates)
(Midpoint)
Years from Cost on
ABD ABD
1 $5,000
$33,000
Discount
Factor
NA
Present
Worth on
ABD
$5,000
$33,000
to
SUBTOTAL P/W
25% INDIRECT
10% CONTINGENCY
TOTAL
$38,000
$9,500
$4,750
$53,000
* The total has been rounded up to the nearest $1,000.
Coal Storage Yard
Alternative 2
Capital Costs
-------
Ul
LIFE CYCLE COST
10/4/95 11:06
Project Name: OU4 Analysis Base Date: Dec 94
Project Number: JV8000 Analyis End Date: Dec 94
Installation & Location: OU4 - Coal Storage Yard BOD for Analysis:
Alt. No. : 2 . Annual Discount Rate: 0.07
Title: Institutional Controls and Groundwater Monitoring- Escalation Rate: 0.00
Natural Attenuation of Groundwater with Semi-Annual
Monitoring and Institutional Controls
YEARS
ANNUAL COSTS (Semi-Annual Sampling) First
FROM ABD: Total
Last Number of
GROUNDWATER MONITORING (25 WELLS @ $2610/WELL) : Incurred Incurred Payments
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
1.
Equipment Shipping
Sampling Equipment (jars, bailers, labels, rope, etc.)
Travel Expenses (Air Fare, Per Diem, Rental Car, etc.)
Field Team (2-Man, 25-hrs @ $160/hr)
Sample Shipping Costs (20 Coolers at $75/Cooler)
Sample Analysis Costs (Two Analytes)
Quality Assurance Report (0.5-hr per analyt @ $80/hr)
Summary Report
Investigation Derived Waste Management
Administration Costs
INSTITUTIONAL CONTROL:
Maintain Fencing
1
1
1
1
1
1
1
1
1
1
1
35
35
35
35
35
35
35
35
35
35
35
35
35
35
35
35
35
35
35
35
35
35
Annual
Cost on Discount
ABD
$2
$3
$8
$3
$26
$4
$4
$8
$2
Present
Worth on
Factor
600
,750
,030
,000
,000
,250
,000
,640
, 000
,500
$500
12
12
12
12
12
12
12
12
12
12
12
948
948
948
948
948
948
948
948
948
948
948
SUBTOTAL P/W
$
$
$
$
$
$
$
$
$
$
$
$
10% CONTINGENCY
TOTAL
$
ABD
7,
35,
39,
103,
38,
339,
51,
60,
103,
32,
6,
819,
$81,
902,
769
607
232
584
844
885
792
079
584
370
474
220
922
000
* The total has been rounded up to the nearest $1,000.
Coal Storage Yard
Alternative 2
Annual Costs
-------
LIFE CYCLE COST
10/4/95 10:17
10
Project Name: OU4
Project Number: JV8000
Installation .& Location: OU4 - Coal Storage Yard
Alt. No. : 3
Title: Excavation, Low Temp Thermal Desorption of
Soils, with Natural Attenuation of Groundwater,
Semi-Annual Environmental Monitoring and
Institutional Controls
Analysis Base Date: Dec 94
Analyis End Date: Dec 94
BOD for Analysis:
Annual Discount Rate: 0.07
Escalation Rate: 0.00
ONE-TIME COSTS
EXCAVATION AND BACKFILL:
1. Excavation (240 tons @ $100.00/ton)
2. Backfill (240 tons @ $10.00/ton)
LOW TEMP THERMAL DESORPTION (LTTD) OF SOILS
1. LTTD for Soil (240 tons @ $250/ton)
GROUNDWATER MONITORING (25 WELLS @ $200/Well)
1. Monitoring Workplan
INSTITUTIONAL CONTROLS
1. No Capital Costs
(Midpoint) Present
Years from Cost on Discount Worth on
ABD ABD Factor ABD
1 $24,000 NA $24,000
1 $2,400 $2,400
$60,000 NA $60,000
$5,000 NA $5,000
$0 NA $0
SUBTOTAL P/W $91,400
25% INDIRECT $22,850
10% CONTINGENCY $11,425
TOTAL $126,000
The total has been rounded up to the nearest $1,000.
Coal Storage Yard
Alternative 3
Capital Costs
-------
Tabl
LIFE CYCLE COST
10/4/95 10:15
Project Name: OU4
Project Number: JV8000
Installation & Location: OU4 - Coal Storage Yard
Alt. No. : 3
Title: Excavate, Low Temp Thermal Desorption of
Soils, with Natural Attenuation of Groundwater,
Semi-Annual Environmental Monitoring and
Institutional Controls
Analysis Base Date: Dec 94
Analyis End Date: Dec 94
BOD for Analysis:
Annual Discount Rate: 0.07
Escalation Rate: 0.00
ANNUAL COSTS
EXCAVATION:
1. No Annual Costs
LOW TEMP THERMAL DESORPTION OF SOILS:
1. No Annual Costs
GROUNDWATER MONITORING (25 WELLS @ $2610/WELL):
1. Equipment Shipping
2. Sampling Equipment (jars, bailers, labels, rope, etc.)
3. Travel Expenses (Air Fare, Per Diem, Rental Car, etc.)
4. Field Team (2-Man, 25-hrs @ $160/hr)
5. Sample Shipping Costs (20 Coolers at $75/Cooler)
6. Sample Analysis Costs (Two Analytes)
7. Quality Assurance Report (0.5-hr per analyt @ $80/hr)
8. Summary Report
9, Investigation Derived Waste Management
10. Administration Costs
INSTITUTIONAL COSTS:
1. No Annual Costs
YEARS FROM ABD: Total
First Last Number of
Incurred Incurred Payments
NA NA
Annual
Cost on
ABD
NA $0
NA
NA
20
20
20
20
20
20
£. U
20
20
20
NA
NA
$0
Discount
Factor
NA
NA
Present
Worth on
ABD
$0
$0
20
20
20
20
20
20
20
20
20
20
NA
$2,
$3,
$8,
$3,
$26,
54,
$4,
$8,
$2,
600
750
030
000
000
250
000
640
000
500
$0
12,
12.
12.
12.
12.
12.
12.
12.
12.
12 .
.409
.409
,409
.409
.409
.409
.409
.409
.409
.409
NA
$
$
$
$
$
$
$
•$
$
$
$
SUBTOTAL P/W
10% CONTINGENCY
TOTAL
7
34
37
99
37
325
49
57
99
31
$778
$77
$857
,445
,125
,599
,272
,227
,736
,636
,578
,272
,023
_
,913
,891
,000
* The total has been rounded up to the nearest $1,000.
Coal Storage Yard
Alternative 3
Annual Costs
-------
Tabled
N)
00
LIFE CYCLE COST
10/4/95 10:25
Project Name: OU4
Project Number: JV8000
Installation & Location: OU4 - Coal Storage Yard
Alt. No. : 4
Title: Excavation, Low Temp Thermal Desorption of
Soils and UV Oxidation of Groundwater with
Semi-Annual Monitoring and Institutional Controls
Analysis Base Date: Dec 94
Analyis End Date: Dec 94
BOD for Analysis:
Annual Discount Rate: 0.07
Escalation Rate: 0.00
ONE-TIME COSTS
EXCAVATION AND BACKFILL:
1. Excavation (240 tons @ $100.00/ton)
2. Backfill (240 tons @ $10.00/ton)
LOW TEMP THERMAL DESORPTION (LTTD) OF SOILS
1. LTTD for Soil (240 tons @ $250/ton)
GROUNDWATER PUMP AND TREAT (UV OXIDATION)
1. Extraction Wells (7 @ 30 If @ $100/lf)
2. Extraction Piping (2625 If @ $30/lf)
3. UV Oxidizers (120 kW system)
4. Post UV Filtration for Metals
5. Building (2000 sf @ $60/sf)
6. Electrical (Controllers, switches, contracting)
7. Equipment Installation (unloading, leveling, anchoring)
8. Plumbing/Misc.(Cooling Water, Steam, H202 Tank)
9. Furnace/Heat Exchangers
10. Pilot Scale Studies for UV Treatment
GROUNDWATER MONITORING (25 WELLS @ $200/Well):
1. Monitoring Workplan
INSTITUTIONAL CONTROL:
1. Fencing ($19.07/LF for 1600-LF and 2 Gates)
(Midpoint)
Years from
ABD
Cost on
ABD
$24,000
$2,400
$60,000
Discount
Factor
NA
NA
$5,000
$33,000
SUBTOTAL P/W
25% INDIRECT
10% CONTINGENCY
TOTAL
NA
NA
Present
Worth on
ABD
$24,000
$2,400
$60,000
1
1
1
1
1
1
1
1
1
1
$21, 000
$78,750
$125,280
$43,500
$120,000
$50,000
$50, 000
$43,500
$3,750
$150,000
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
$21,000
$78,750
$125,280
$43,500
$120,000
$50,000
$50,000
$43,500
$3,750
$150,000
$5,000
$33,000
$810,180
$202,545
$101,273
$1,114,000
The total has been rounded up to the nearest $1,000.
Coal Storage Yard
Alternative 4
Capital Costs
-------
Table A-3
LIFE CYCLE COST
10/18/95 9:47
Project Name: OU4
Project Number: JV8000
Installation & Location: OU4 - Coal Storage Yard
Alt. No. : 4
Title: Excavate, Low Temp Thermal Desorption of
Soils and UV Oxidation of Groundwater with
Semi-Annual Monitoring and Institutional Controls
Analysis Base Date: Dec 94
Analyis End Date: Dec 94
BOD for Analysis:
Annual Discount Rate: 0.07
Escalation Rate: 0.00
ANNUAL COSTS
EXCAVATION:
1. No Annual Costs
LOW TEMP THERMAL DESORPTION OF SOILS
1. No Annual Costs
YEARS FROM ABD: Total
First Last Number of
Incurred Incurred Payments
NA NA
NA
NA
Annual
Cost on
ABD
NA SO
NA
SO
Present
Discount Worth on
Factor ABD
NA SO
NA
SO
N)
VO
PUMP AND TREAT (UV OXIDATION)
1. UV Oxidizers (electrical, H202, lump)
2. Extraction Well Pumps (7 - 8 hp pumps)
3. Sampling (Weekly, ,3 sample points @ $180/point)
4. Metals Filter (filter replacement, consumables)
INSTITUTIONAL CONTROL:
1. Maintain Fencing
GROUNDWATER MONITORING SEMI-ANNUAL (25 WELLS @ $2610/WELL)
1 Equipment Shipping
2. Sampling Equipment (jars, bailers, labels, rope, etc.)
3. Travel Expenses (Air Fare, Per Diem, Rental Car, etc.)
4. Field Team (2-Man, 25-hrs @ $160/hr)
5. Sample Shipping Costs (20 Coolers at $75/Cooler)
6. Sample Analysis Costs (Two Analytes)
7. Quality Assurance Report (0.5-hr per analyt @ $80/hr)
8. Summary Report
9. Investigation Derived Waste Management
10. Administration Costs
$113,100
$36,596
$28,080
$96,027
$500
600
$2,750
$3,030
$8,000
$3,000
$26,250
$4,000
$4,640
$8,000
$2,500
SUBTOTAL P/W
10% CONTINGENCY
TOTAL
5.389
5.389
5.389
5.389
5.389
5.389
5.389
5.389
5.389
5.389
5.389
5.389
5.389
5.389
5.389
I
$
S
$
$
$
$
$
$
$
$
$
$1
$1
$609,
$197,
$151,
$517,
2,
3,
14,
16,
43,
16,
141,
21,
25,
43,
13j_
,816,
$181,
,999,
496
215
323
490
695
233
820
329
112
167
461
556
005
112
473
487
649
000
The total has been rounded up to the nearest $1,000.
Coal Storage Yard
Alternative 4
Annual Costs
-------
Table A1
LIFE CYCLE COST
10/4/95 10:25
Project Name: OU4
Project Number: JV8000
Installation & Location: OU4 - Coal Storage Yard
Alt. No. : 4
Title: Excavation, Low Temp Thermal Desorption of
Soils and UV Oxidation of Groundwater with
Semi-Annual Monitoring and Institutional Controls
Analysis Base Date: Dec 94
Analyis End Date: Dec 94
BOD for Analysis:
Annual Discount Rate: 0.07
Escalation Rate: 0.00
ONE-TIME COSTS
EXCAVATION AND BACKFILL:
1. Excavation (240 tons @ $100.00/»;on)
2. Backfill (240 tons @ $10.00/ton)
(Midpoint)
Years from
ABD
Cost on
ABD
$24,000
$2,400
Discount
Factor
NA
Present
Worth on
ABD
$24,000
$2,400
U)
o
LOW TEMP THERMAL DESORPTION (LTTD) OF SOILS
1. LTTD for Soil (240 tons @ $250/ton)
GROUNDWATER PUMP AND TREAT (UV OXIDATION)
1. Extraction Wells (7 & 30 If @ $100/lf)
2. Extraction Piping (2625 If @ $30/lf)
3. UV Oxidizers (120 kW system)
4. Post UV Filtration for Metals
5. Building (2000 sf @ $60/sf)
6. Electrical (Controllers, switches, contracting)
7. Equipment Installation (unloading, leveling, anchoring)
8. Plumbing/Misc.(Cooling Water, Steam, H2O2 Tank)
9. Furnace/Heat Exchangers
10. Pilot Scale Studies for UV Treatment
GROUNDWATER MONITORING (25 WELLS @ $200/Well):
1. Monitoring Workplan
$60,000
NA
1
1
1
1
1
1
1
1
1
1
$21,000
$78,750
$125,280
$43,500
$120,000
$50,000
$50,000
$43,500
$3,750
$150,000
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
$5,000
NA
$60,000
$21,000
$78,750
$125,280
$43,500
$120,000
$50,000
$50,000
$43', 500
$3,750
$150,000
$5,000
INSTITUTIONAL CONTROL:
1. Fencing ($19.07/LF for 1600-LF and 2 Gates)
'$33,000
SUBTOTAL P/W
25% INDIRECT
10% CONTINGENCY
TOTAL
NA
$33,000
$810,180
$202,545
$101,273
$1,114,000
Q.
a
-o
* The total has been rounded up to the nearest $1,000.
Coal Storage Yard
Alternative 4
Capital Costs
-------
Table*
LIFE CYCLE COST
10/4/95 10:28
U)
Project Name: OU4
Project Number: JV8000
Installation & Location: OU4 - Coal Storage Yard
Alt. No. : 5
Title: Vacuum Extraction/Steam Injection and Bio-
venting of Soils and Natural Attenuation of
Groundwater with Semi-Annual Environmental
Monitoring and Institutional Controls
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
1.
1.
ONE-TIME COSTS
VES:
Extraction Wells (2 @ $2500/ea.)
Injection Wells (2 @ $2500/ea.)
Extraction Well Piping (150 If @ $30/lf)
Injection Well Piping (150 If @ $30/lf)
Joints (10 @ $16/ea)
Vacuum Gauges (2 @ $75/ea)
Sampling Ports (2 @ $30/ea)
Gas Flow Meter (2 8 $300/ea)
Extraction Blowers
Injection Blowers
Air/Water Separators (1 @ $2,400/ea)
Heat Exchanger (1 @ $1400/ea)
Housing Shed (1 @ $8500/ea)
Heating System (1 @ $10,000)
Pilot Tests
INSTITUTIONAL CONTROL:
Fencing ($19.07/LF for 1600-LF and 2 Gates)
ANNUAL GROUNDWATER MONITORING (25 WELLS 9 $2 00 /Well) :
Monitoring Workplan
Analysis Base Date: Dec 94
Analyis End Date: Dec 94
BOD for Analysis:
Annual Discount Rate: 0.07
Escalation Rate: 0.00
(Midpoint)
Years from
ABD
1
1
1
1
1
3
1
1
1
1
1
1
1
1
1
1
1
Present
Cost on
ABD
$5,000
$5, 000
$4,500
$4, 500
$160
$150
$60
$600
$10,500
$10,500
$2,400
$1,400
$8,500
$10,000
$10,000
$33,000
$5,000
SUBTOTAL P/W
25% INDIRECT
Discount
Factor
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
10% CONTINGENCY
TOTAL
Worth
on
ABD
$5
$5
$4
$4
$10
$10
$2
$1
$8
$10
$10
$33
$5
$111
$27
$13
$153
,000
, 000
,500
, 500
$160
$150
$60
$600
,500
,500
,400
,400
,500
,000
,000
,000
,000
,270
,818
,909
, 000
The total has been rounded up to the nearest $1,000.
Coal Storage Yard
Alternative 5
Capital Costs
-------
H
CO
NJ
LIFE CYCLE COST
10/4/95 10:29
Project Name: OU4 Analysis Base Date: Dec 94
Project Number: JV8000 Analyis End Date: Dec 94
Installation & Location: OU4 - Coal Storage Yard BOD for Analysis:
Alt. No. : 5 . Annual Discount Rate: 0.07
Title: Vacuum Extract/Steam (VES) , Biovent, with Natural Escalation Rate: 0.00
Attenuation of Groundwater, Semi-Annual
Environmental Monitoring and Institutional Controls
YEARS
ANNUAL COSTS First
FROM ABD: Total
Last Number of
VES Incurred Incurred Payments
1.
2
1.
1
2.
3.
4.
5.
6.
7.
8.
9
10
Power for Blowers (20 hp @ $0 . 10/kW-hr, runs continuous)
Misc. (Monitoring, Admin, Maintenance, etc)
INSTITUTIONAL CONTROL:
Maintain Fencing
GROUNDWATER MONITORING (25 WELLS @ $2610/WELL) :
Equipment Shipping
Sampling Equipment (jars, bailers, labels, rope, etc.)
Travel Expenses (Air Fare, Per Diem, Rental Car, etc.)
Field Team (2-Man, 25-hrs @ $160/hr)
Sample Shipping Costs (20 Coolers at $75/Cooler)
Sample Analysis Costs (Two Analytes)
Quality Assurance Report (0.5-hr per analyt @ $80/hr)
Summary Report
Investigation Derived Waste Management
Administration Costs
1
1
1
1
1
1
1
1
1
1
1
1
1
3
3
23
23
23
23
23
23
23
23
23
23
23
3
3
23
23
23
23
23
23
23
23
23
23
23
Annual
Cost on Discount
ABD
$17
$20
$2
$3
$8
$3
$26
$4
$4
$8
$2
Present
Worth on
Factor
,520
,000
$500
600
,750
,030
,000
,000
,250
,000
,640
,000
,500
2.
2.
11
11
11
11
11
11
11
11
11
11
11
6243
6243
.272
.272
.272
.272
.272
.272
.272
.272
.272
.272
.272
$
$
$
$
$
$
$
$
$
$
$
SUBTOTAL P/W
10% CONTINGENCY
TOTAL
ABD
$45,
$52,
5,
6,
30,
34,
90,
33,
295,
45,
52,
90,
28,
$811,
$81,
$893,
978
486
636
763
998
154
176
816
890
088
302
176
180
643
164
000
* The total has been rounded up to the nearest $1,000.
Coal Storage Yard
Alternative 5
Annual Costs
-------
Tabll
LIFE CYCLE COST
10/4/95 10:35
Project Name: OU4
Project Number: JV8000
Installation & Location: OU4 - Coal Storage Yard
Alt. No. : 6
Title: Vacuum Extraction/Steam Injection and Bioventing
of Soils and Air Sparging of Groundwater with
Semi-Annual Monitoring and Institutional Controls
ONE-TIME COSTS
VES:
1. Extraction Wells (2 9 $2500/ea.)
2. Injection Wells (2 9 S2500/ea.)
3. Extraction Well Piping (150 If 8 $30/1£)
4. Injection Well Piping (150 If 8 $30/lf)
5. Joints (10 @ $16/ea)
6. Vacuum Gauges (2 8 $75/ea)
7. Sampling Ports (2 @ $30/ea)
8. Gas Flow Meter (2 9 $300/ea)
9. Extraction Blowers
10. Injection Blowers
11. Air/Water Separators (1 @ $2,400/ea)
12. Heat Exchanger (1 9 $1400/ea)
13. Housing Shed (1 9 $8500/ea)
l-> 14. Heating System (1 @ $10,000)
l*> 15. Pilot Tests (1 9 $10,000)
w
AIR SPARGING:
1. Extraction Wells (10 8 $2500/ea.)
2. Injection Wells (10 0 $2500/ea.)
3. Extraction Well Piping (750 If 9 $30/lf)
4. Injection Well Piping (750 If @ $30/lf)
5. Joints (50 9 $16/ea)
6. Vacuum Gauges (10 9 $75/ea)
7. Sampling Ports (10 8 $30/ea)
8. Gas Flow Meter (10 8 $300/ea)
9. Extraction Blowers
10. Injection Blowers
11. Air/Water Separators 11 9 $2,400/ea)
12. Heat Exchanger (1 8 $1400/ea)
13. Housing Shed (I 8 $8500/ea)
14. Heating System (1 8 $10,000)
15. Pilot Tests (1 0 $10,000)
Analysis Base Date: Dec 94/June 95
Analyis End Date: Dec 94/June 95
BOD for Analysis: Dec 95/June 95
Annual Discount Rate: 0.07
Escalation Rate: 0.00
(Midpoint )
Years from
ABD
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
3
1
1
1
1
1
1
1
1
1
Cost on
ABD
$5,000
$5,000
$4,500
$4,500
$160
$150
$60
$600
$10,500
$10,500
$2,400
$1,400
$8,500
$10,000
$10,000
$25,000
$25,000
$22,500
$22,500
$800
$750
$300
$3,000
$10,500
$10,500
$2,400
$1,400
$8,500
$10,000
$10,000
Discount
Factor
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Present
Worth on
ABD
$5,000
$5, 000
$4,500
$4,500
$160
$150
$60
$600
$10,500
$10,500
$2,400
$1,400
$8,500
$10,000
$10,000
$25,000
$25,000
$22,500
$22,500
$800
$750
$300
$3,000
$10,500
$10,500
$2,400
$1,400
$8,500
$10,000
$10,000
GROUNDWATER MONITORING (25 WELLS 8 $200/Well) :
1. Monitoring Workplan
INSTITUTIONAL CONTROL:
1. Fencing ($19.07/LF for 1600-LF and 2 Gates)
$5,000
$33,000
$5,000
$33,000
The total has been rounded up to the nearest $1,000.
SUBTOTAL P/W
25% INDIRECT
10% CONTINGENCY
TOTAL
$264,420
$66,105
$33,053
$364,000
Coal Storage yard
Alternative 6
Capital Costs
-------
Table
LIFE CYCLE COST
10/4/95 10:35
U)
Project Name: OU4
Project Number: JV8000
Installation & Location: OU4 - Coal Storage Yard
Alt. No. . 6
Title: Vacuu/p Extraction/Steam Injection and Bioventing
of Soils and Air Sparging of Groundwater with
Semi-Annual Monitoring and Institutional Controls
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
1.
2.
3.
4.
5.
6
7
8
9
10
11
12
13
14
15
1.
1
ONE-TIME COSTS
VES:
Extraction Wells (2 9 $2500/ea.)
Injection Wells (2 9 $2500/ea.)
Extraction Well Piping (150 If 9 530/lfl
Injection Well Piping (150 If 9 $30/lf)
Joints (10 e $16/ea)
Vacuum Gauges 12 8 $75/ea)
Sampling Ports (2 « $30/ea)
Gas Flow Meter (2 9 $300/ea)
Extraction Blowers
Injection Blowers
Air/Water Separators (1 9 $2,400/ea)
Heat Exchanger (1 9 $1400/ea)
Housing Shed (1 9 $8500/ea)
Heating System (1 9 $10,000)
Pilot Tests (1 8 $10,000)
AIR SPARGING:
Extraction Wells (10 9 $2500/ea.)
Injection Wells (10 9 $2500/ea.l
Extraction Well Piping (750 If 9 $30/lf)
Injection Well Piping (750 If 9 $30/lf)
Joints (50 9 $16/ea)
Vacuum Gauges (10 9 $75/ea)
Sampling Ports (10 9 $30/ea)
Gas Flow Meter (10 9 $300/ea)
Extraction Blowers
Injection Blowers
Air/Water Separators (1 9 $2,400/ea)
Heat Exchanger (1 9 $1400/ea)
Housing Shed (1 9 $B500/ea)
Heating System (1 9 $10.0001
Pilot Tests (1 9 $10,000)
GROUNDWATER MONITORING (25 WELLS 9 S200/Well):
Monitoring Workplan
INSTITUTIONAL CONTROL,*
Fencing (S19.07/LF for 1600-LF and 2 Gates)
Analysis Base Date: Dec 94/June 95
Analyis End Date: Dec 94/June 95
BOD for Analysis: Dec 95/June 95
Annual Discount Rate: 0.07
Escalation Rate: 0.00
(Midpoint )
Years from
ABD
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
3
1
1
1
1
1
1
1
1
1
1
1
Cost on
ABD
$5.000
$5.000
$4.500
$4,500
$160
$150
$60
$600
$10,500
$10,500
. $2,400
$1,400
$8,500
$10.000
$10,000
$25,000
$25,000
$22,500
$22.500
$800
$750
$300
$3.000
$10,500
$10,500
$2,400
$1,400
$8,500
$10,000
$10,000
$5,000
$33,000
SUBTOTAL P/W
25% INDIRECT
Discount
Factor
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
10% CONTINGENCY
TOTAL
Present
Worth on
ABD
$5. 000
$5,000
$4.500
$4.500
$160
$150
$60
$600
$10. 500
$10.500
$2.400
$1. 400
$8,500
$10,000
$10,000
$25,000
$25,000
$22,500
$22.500
$800
$750
$300
$3.000
$10,500
$10,500
$2,400
$1,400
$8,500
$10,000
$10,000
-
$5.000
$33.000
$264,420
$66, 105
$33.053
$364.000
The total has been rounded up to the nearest $1,000.
Coal Storage Yard
Alternative 6
Capital Costs
-------
Table A-3
W
Ul
LIFE CYCLE COST
10/18/95 9:48
Project Name: OU4 Analysis Base Date: June 95
Project Number: JV8000 Analyis End Date: June 95
Installation & Location: OU4 - Coal Storage Yard BOD for Analysis: June 95
Alt. No. : *> . Annual Discount Rate: 0.07
Title: Vacuum Extraction/Steam Injection and Bioventing Escalation Rate: 0.00
of Soils with Air Sparging of Groundwater,
Semi-Annual Monitoring, and Institutional Controls.
YEARS
ANNUAL COSTS First
FROM ABD: Total
Last Number of
VES: Incurred Incurred Payments
1.
2.
1.
2.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
1.
Power for Blower Sys . (20 hp @ SO.lO/kW-hr, contin.)
Misc. (Monitoring, Admin, Maintenance, etc)
AIR SPARGING:
Power for Blower Sys. (50 hp 9 $0.10/kw-hr, contin.)
Misc. (Monitoring, Admin, Maintenance, etc)
GROUNDWATER MONITORING (25 WELLS @ S2610/WELL) :
Equipment Shipping
Sampling Equipment (jars, bailers, labels, rope, etc.)
Travel Expenses (Air Fare, Per Diem, Rental Car, etc.)
Field Team (2-Man, 25-hrs @ $160/hr)
Sample Shipping Costs (20 Coolers at $75/Cooler)
Sample Analysis Costs (Two Analytes)
Quality Assurance Report (0.5-hr per analyt @ $80/hr)
Summary Report
Investigation Derived Waste Management
Administration Costs
INSTITUTIONAL CONTROL:
Maintain Fencing
19 9
19 9
19 9
19 9
19 9
19 9
19 9
19 9
19 9
1 9 0
19 9
19 9
19 9
19 9
19 9
Annual Present
Cost on Discount Worth on
ABD Factor ABD
$17,520 6.515 $114,
$20,000 6.515 $130,
$43,800 6.515 $285,
$20,000 6.515 $130,
600 6.515 $ 3,
$2,750 6.515 $ 17,
$3,030 6.515 $ 19,
$8,000 6.515 $ 52,
$3,000 6.515 $ 19,
$26,250 6.515 $ 171,
$4,000 6.515 $ 26,
$4,640 6.515 $ 30,
$8,000 6.515 $ 52,
$2,500 6.515 $ 16,
$500 6.515 $_ 3,
SUBTOTAL P/W $1,072,
10% CONTINGENCY $107,
TOTAL $1,180,
143
300
357
300
909
916
740
120
545
019
060
230
120
288
258
305
231
000
The total has been rounded up to the nearest $1,000.
Coal Storage Yard
Alternative 6
Annual Costs
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