United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R09-93/090
December 1992
Superfund
Record of Decision:
Williams Air Force Base, AZ
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I-
I
50272.101
REPORT DOCUMENTATION I" REPORT NO. 2. 3. A8Clplent'8 Acc8aalon No.
PAGE EPA/ROD/R09-93/090
4. Title and Subtitle 5. Aeport Date
SUPERFUND RECORD OF DECISION 12/30/92
Williams Air Force Base, AZ 6.
First Remedial Action
7. Author(a) 8. Performing Organization Rapt. No.
9. Performing Organization Nama and Addr- 10 ProJec:t TaaklWork Unit No.
11. Contract(C) or Grant(G! No.
(C)
(G)
12. Sponaorlng Organization Nama and Add,..a 13. Type 0' Report & Period Covered
U.S. Environmental Protection Agency
401 M Street, S.W. 800/800
Washington, D.C. 20460 14.
15. Supplementary Nota.
PB94-964514
16. Abstract (Umlt: 200 word.)
The 4, 127-acre Williams Air Force Base site is an active military installation located
in Maricopa County, Arizona. Land use in the area is predominantly agricultural, with
some small, urban areas located 5 to 15 miles northeast and northwest of the Base. The
site lies between a 100- and 500-year floodplain in the Gila River Basin; borders
several mountains; and overlies an upper and a deep aquifer. The site consists of
runway and airfield operations, industrial areas, housing, and recreational facHities.
The 3,029 military personnel and 869 civilian employees stationed at.the Base,
including an estimated 2,700 people who actually reside there, use the estimated 90
domestic permitted wells located within a 3-mile radius to obtain their water supply.
These wells are not affected by the site contamination. In 1942, the site was
commissioned as a flight training school and, in 1949, training activities with jet
aircraft were initiated. Since 1942, liquid fuels have been stored onsite in the
Liquid Fuels Storage Area (LFSA) in a series of underground storage tanks at Facilities
688, 514, 538, and 548. In 1954 and 1962, "above-ground storage tanks were constructed
at Facilities 557 and 556, respectively. In 1984, the Department of Defense's.
Installation Restoration Program initiated a review of chemical handling and disposal
(See Attached Page)
17. Document AnalyaJa L De8crlptora
Record of Decision - Williams Air Force Base, AZ
First Remedial Action
Contaminated Media: soil, gw
Key Contaminants: VOCs (benzene, PCE, toluene, xylenes), other organics (P AHs,
phenols), metals (chromium, lead)
b: IdentlfieralOpen-Endad Tarms
c. COSATI FlalcUGroup
18. Availability Statement 19. Security Clus (ThIs Report) 21. No. 0' PaglS
None 146
20. Security CIa8s (This Page) 22. Price
None
(See ANSI-Z39.18)
S../nstructlons on Reve,*,
OPTIONAL FORM 272 (4-77)
(Formerly NTIS-as)
Department 0' Commerce
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EPA/ROD/R09-93/090
Williams Air Force Base, AZ
First Remedial Action
Abstract (Continued)
practices and identified several potential sites where hazardous materials were disposed
of or handled. Site investigations, conducted in 1984, 1986, 1989, and 1991, determined
that releases of jet fuel and aviation gasoline have contaminated the onsite soil and
ground water. The results of these analyses indicate that fuel-related contamination
generally is not present in the first foot of surface soil and, therefore, does not
warrant further action. In addition, a floating free-phase ground water plume has been
identified in the upper aquifer. As a result, in 1988, all of the 4.4-acre LFSA was
closed, except for Facilities 556 and 557. In 1990 and 1991, 14 USTs at Facilities 688,
514, 538, and 548 were removed, along with the distribution lines leading to them. In
addition, five steel tanks were discovered and removed. By late 1991, 36 ground water
monitoring wells had been installed at the LFSA. This ROD addresses the first 25 feet of
contaminated soil and ground water in the upper aquifer at the LFSA, as OU2. Future RODs
will address contaminated soil and ground water at 12 of the other 13 areas on the Base,
asOU1i and contaminated soil below 25 feet at the LFSA and any remaining soil ,and ground
water contamination, as OU3. The primary contaminants ,of concern affecting the soil and
ground water are VOCs, including benzene, PCE, toluene, and xylenesi other organics,
,including PARs and phenols; and metals, including chromium and lead.
The selected remedial action for this site includes treating approximately 54,000 yd3 of
contaminated surface and subsurface soil onsite using in-situ, bioenhanced soil vapor
extraction (SVE), followed by biodegradation; extracting between 650,000 and 1,400,000
gallons of free-phase floating jet fuel and 170,000,000 gallons of contaminated ground
water using extraction wells, followed by oil/water separation to capture all free-phase
produce prior to treatment of the water; reusing or disposing of the free-phase product
offsite at an authorized disposal facility; providing for a contingent remedy to pre-treat
the extracted ground water, using precipitation, flocculation, clarification, filtration,
ion exchange, or acid treatment to remove solids that may interfere with the treatment and
to reduce metal contamination to action levels, if necessary, based on treatability
studies; treating the ground water onsite using air stripping to reduce volatile
contaminant concentrations to below action levels; conducting treatability studies to
determine whether post-treatment is necessary to treat semi-volatile contaminationi
reinjecting the treated ground water into the aquifer through injection wells and/or
discharging it onsite to the wastewater treatment plant for use on the golf course;
treating the emissions from the SVE and the air stripper onsite using fume incineration;
providing a contingent remedy to treat the emissions onsite, using vapor-phase carbon
adsorption, if the fume incinerator cannot achieve an acceptable emission level of less
than three pounds Per day of organic vapors; monitoring soil and ground water; and
implementing institutional controls, including deed and ground water use restrictions.
The estimated present worth cost for this remedial action ranges from $7,900,000 to
$21,100,000, which includes an estimated O&M cost ranging from $600,000 to $8,000,000 for
30 years.
PERFORMANCE STANDARDS OR GOALS:
Chemical-specific soil cleanup goals are based on Federal and State standards, and include
acetone 12,000 mg/kg; antimony 47 mg/kg; benzene 45 mg/kg; beryllium 1-1.5 mg/kg;
bis(2-ethylhexyl)phthalate 95 mg/kg; cadmium 58 mg/kg; chlorobenzene 2,300 mg/kg; 1,2-
dichlorobenzene 10,000 mg/kgi 1,3-dichlorobenzene 10,000 mg/kgi 1,4-dichlorobenzene 55
mg/kgi diethylphthalate 94,000 mg/kgi di-n-butylphthalate 12,000 mg/kg; ethylbenzene
12,000 mg/kg; lead 15-150 mg/kg; methylene chloride 180 mg/kg; toluene 23,000 mg/kg; and
xylenes 230,000 mg/kg. Chemical-specific ground water cleanup goals are based on SDWA MCLs
and State standards, and include antimony 0.006 mg/l; benzene 0.005 mg/l;
bis(2-ethylhexyl)phthalate 0.006 mg/l; chromium 0.1 mg/l; copper 1.3 mg/li 1,2-DCA 0.005
mg/l; ethylbenzene 0.7 mg/li lead 0.015 mg/li methylene chloride 0.005 mg/li 2-
methylphenol 0.87 mg/li 4-methylphenol 0.87 mg/li naphthalene 0.028 mg/li nickel 0.1 mg/li
~CE 0.00.5 mg/li phenol 4.2 mg/li silver 0.05 mg/li toluene 1 mg/li trichlorofluoromethane
2.1 mg/l; xylenes 10 mg/l; and zinc 1.4 mg/l.
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FINAL
RECORD OF DECISION
OPERABLE UNIT 2
WilLIAMS AIR FORCE BASE
PHOENIX, ARIZONA
Prepared by:
IT Corporation
312 Directors Drive
Knoxville, Tennessee 37923
IT Project No. 409735
Prepared for:
Martin Marietta Energy Systems, Inc.
Post Office Box 2002
Oak Ridge, Tennessee 37831-6501
December 1992
KN/NEW. COY 112-1S-92/F
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Table 01 Contents
Page
1 .0 Declaration
1.1 Site Name and Location
1.2 Statement of Basis and Purpose
1.3 Assessment of the Site
1.4 Description of the Selected Remedy
1.5 Declaration
1-1
1-1
1-1
1-2
1-2
1-5
2.0 Decision Summary
2.1 Site Name, Location, and Description
2.2 Site History and Enforcement Activities
2.2.1 Site History
2.2.2 Enforcement Activities
2.3 Highlights of Community Participation
2-1
2-1
2-5
2-5 .
2-6
2-6
3.0 Scope and Role of Operable Unit
3-1
4.0 Summary of Site Characteristics
4.1 Soil Contamination
4.2 Groundwater Contamination
4.3 Contaminant Fate and Transport
4.3.1 Chemical Persistence
4.3.2 Contaminant Migration
4-1
4-1
4-2
4-3
4-3
4-4
5.0 Summary of Potential Site Risks
5.1 Chemicals of Potential Concern
5.1.1 Groundwater
5.1.2 Soil
5.2 Exposure Assessment
5.2.1 Groundwater
5.2.2 Surface Soil
5.2.3 Subsurface Soil
5-1
5-1
5-1
5-1
5-3
5-3
5-4
5-5
KN/NEW.ROD/12-15-92/F
1
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Table of Contents (Continued)
Page
5.3 Contaminant Toxicity Information
5.4 Risk Characterization
5.4.1 Carcinogenic Effects
5.4.2 Noncarcinogenic Effects
5.5 Environmental Evaluation
5-6
5-7
5-7
5-8
5-10
6.0 Description of Alternatives
6.1 Selection of Chemicals Requiring Treatment
6.1.1 Groundwater
6.1.2 Soil
6.2 Alternative Description
6-1
6-1
6-2
6-4
6-4
7.0 Comparative Analysis of Alternatives
7.1 Overall Protection of Human Health and the Environment
7.2 Compliance with ARARs
7.3 Long-Term Effectiveness and Permanence
7.4 Reduction of Toxicity, Mobility, or Volume Through Treatment
7.5 Short-Term Effectiveness
. 7.6 Implementability
7.7 Cost
7.8 State Acceptance
7.9 Community Acceptance
7-1
7-1
7-1
7-1
7-2
7-3
7-4
7-5
7-6
7-6
8.1.2.1 Extraction Method
8.1.2.2 Pretreatment
8.1.2.3 Emission Abatement
8.1.2.4 Posttreatment
8.1.2.5 Injection
8.1.3 Information Summary
8-1
8-1
8-2 .
8-2
8-2
8-2
8-3
8-3
8-3
8-3
8.0 The Selected Remedy
8.1 Groundwater Remediation
8.1.1 Decision Process
8.1.2 Decision Points
KN/NEW.ROD/12-16-92/F
11
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Table of Contents (Continued)
8.2 Soil Remediation
8.2.1 Decision Process
8.2.2 Decision Points
8.2.2.1 Microbe Selection
8.2.2.2 Nutrient Delivery System
8.2.2.3 Enhancement Addition
8.2.2.4 Emission Abatement
8.2.3 Information Summary
9.0 Statutory Determinations
9.1 Protection of Human Health and the Environment
9.2 Attainment of ARARs
9.3 Cost Effectiveness
9.4 Utilization of Permanent Solutions and Alternative Treatment Technologies or
Resource Recovery Technologies to the Maximum Extent Possible
9.5 Preference for Treatment as a Principal Element
10.0 Responsiveness Summary
10.1 Overview
10.2 Background on Community Involvement
10.3 Summary of Comments Received During the Public Comment Period and
USAF Responses
10.4 Community Relations Activities at Williams Air Force Base
10.5 Letters Recommending Methods and Products
11.0 Bibliography
Appendix A - Applicable or Relevant and Appropriate Requirements
Appendix B - Cost Estimates for Selected Alternative
Appendi~ C - L~ ::ers Reco~'. :nending ':thods and Products
KN/NfNI.ROD/12-16-92/F
11l
Page
8-4
8-4
8-4
8-4
8-5
8-5
8-5
8-6
9-1
9-1
9-2
9-2
9-2
9-2
10-1
10-1
10-1
10-3
10-13
10-14
11-1
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List of Tables
Table
2-1
4-1
4-2
4-3
4-4
5-1
5-2
5-3
5-4
5-5
5-6
5-7
5-8
6-1
6-2
7-1
7-2
Title
Folio ws Page
2-1
4-1
4-1
4-1
4-1
5-1
5-1
5-2
5-4
Cities Surrounding Williams AFB
Chemicals Identified in Subsurface Soil at OU-2 by AeroVironment
Chemicals Identified in Subsurface Soil at OU-2 by IT
Chemicals Identified in Surface Soil at OU-2 by IT
Chemicals Identified in Groundwater Monitoring Wells at OU-2
Chemicals of Potential Concern in Groundwater
Chemicals of Potential Concern in Subsurface Soil
Chemicals of Potential Concern in Surface Soil
Estimated Risk Due to Exposure via Vegetable Ingestion Pathway
Summary of Potential Incremental Lifetime Cancer Risks (ILCR) Associated
With OU-2 At Williams AFB: Current Land Use
Summary of Potential Incremental Lifetime Cancer Risks (ILCR) Associated
With OU-2 at Williams AFB: Future Land Use
Summary of Potential Hazard Indices (HI) Associated With OU-2 at
Williams AFB: Current Land Use
Summary of Potential Hazard Indices (HI) Associated With OU-2 at
Williams AFB: Future Land Use
Chemicals of Potential Concern in Groundwater at OU-2 and Treatment
Requirements to Meet Action Levels 6-2
Chemicals of Potential Concern in Soil at OU-2 and Treatment Requirements to
Meet Action Levels 6-2
Comparison of Cleanup Alternatives 7-1
Summary of Remedial Alternative Cost Estimates 7-5
5-6
5-6
5-6
5-6
KN/NEW. ROD/12-IS-92/F
IV
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List of Figures
Figure
2-1
2-2
2-3
2-4
4-1
4-2
6-1
6-2
8-1
8-2
Title
Follows Page
Williams Air Force Base Location Map
Williams Air Force Base Site Map Operable Unit 2
Williams Air Force Base Soil Boring and SOY Survey Locations
Williams Air Force Base Liquid Fuels Storage Area Monitoring Well
Network
Williams Air Force Base Areas of Soil Contamination at OU-2
Williams Air Force Base Liquid Fuels Storage Area 5 ppb Benzene
Isoconcentration Line as of October 1991
Williams Air Force Base Conceptual Schematic for Alternative C
Williams Air Force Base Conceptual Schematic for Alternative D
Groundwater Treatment Flow Diagram
Soil Treatment Flow Diagram
KN/NEW.ROD/12-1S-92/F
v
2-1
2-1
2-5
2-6
4-2
4-3
6-9
6-12
8-2
8-4
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List of Acronyms
ADEQ
ADWR
AFB
ARAR
ATC
AV
A VGAS
BTEX
BTU
CAG
CDI
CERCLA
cfm
CFR
CPF
ES
Energy Systems
FFA
FS
gpm
HBGL
HI
ILCR
IRP
IT
JP-4
LFSA
LOEL
MAG
MCL
MOC
msl
NCP
NOAA
NOEL
NPL
O&M
OU-I
OU-2
OU-3
ppb
ppm
QAPP
KN/NEW.ROD/12-1S-92/F
Arizona Department of Environmental Quality
Arizona Department of Water Resources
Air Force Base
applicable or relevant and appropriate requirement
Air Training Command
Aero Vironment, Inc.
aviation gas
benzene, toluene, ethyl benzene
British thermal unit
Carcinogen Assessment Group
chronic daily intake
Comprehensive Environmental Response, Compensation, and Liability Act
cubic feet per minute
Code of Federal Regulations
carcinogenic potency factor
Engineering-Science
Martin Marietta Energy Systems, Inc.
Federal Facilities Agreement
feasibility study
gallons per minute
Health-Based Guidance Levels
hazard indices
incremental lifetime cancer risk
Installation Restoration Program
IT Corporation
Jet Propulsion Fuel Grade 4
Liquid Fuels Storage Area
lowest observed effect level
Maricopa Association of Governments
Maximum Contaminant Level
methods of characterization
mean seal level
National Contingency Plan
. National Oceanographic and Atmospheric Association
no observed effect level
National Priority List
operation and maintenance
Operable Unit 1
Operable Unit 2
Operable Unit 3
parts per billion
parts per million
quality assurance project plan
-
VI
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List of Acronyms (Continued)
RCRA
RID
RI
RME
ROD
RWCD
SARA
SOY
SVE
TBC
TOX
TPH
USAF
U.S. EPA
UST
VOC
KN/NEW.RODIl2-1S-92IF
Resource Conservation and Recovery Act
reference dose
remedial investigation
reasonable maxiJ:~ :":::1 exposure
record of decision
Roosevelt Water Control District
Superfund Amendments and Reauthorization Act
soil organic vapor
soil vapor extraction
to be considered
total organic halogens
total petroleum hydrocarbons
U.S. Air Force
U.S. Environmental Protection Agency
underground storage tank
volatile organic compounds
Vll
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1.0 Declaration
1. 1 Site Name and Location
Williams Air Force Base (AFB) is located in Maricopa County, east of the City of Chandler,
Arizona. Operable Unit 2 (OU-2) of the Williams AFB National Priority List (NPL) site is
located at the Base's Liquid Fuels Storage Area (LFSA), which is also referred to by its site
designation" ST -12" .
1.2 Statement of Basis and Purpose
This Record of Decision (ROD) selects a remedial action for site cleanup of OU-2, which is
defined as groundwater and the first 25 feet of soil at ST-12. Soil below 25 feet will be
investigated as a separate operable unit because impact on human health and the environment
has not been completely determined.
A total of 14 areas with potential contamination, including ST-12, are identified on Williams
AFB for remedial investigation. Environmental cleanup of groundwater and the top 25 feet
of soil at ST -12 only pertains to OU-2, while cleanup of the remaining 13 areas and soil
below 25 feet at ST-12 will be completed under other operable units. Upon completion of
Remedial Investigations (RI) of all areas, a Base-wide Feasibility Study (FS) will be
performed, a Base-wide Proposed Plan will be presented, and a Base-wide Record of
Decision (ROD) will be issued that ensures all necessary and selected remedial measures are
integrated into the selected Base-wide remedies.
The U.S. Air Force (USAF) has investigated OU-2 for potential contamination in the top 25
feet of soil and in groundwater. The 13 other areas and soil below 25 feet in depth at
ST-12 are addressed in Operable Unit 1 (OU-l) and Operable Unit 3 (OU-3). OU-2 is being
addressed first for remedial action in order to expedite cleanup of what is believed to be the
most contaminated ponion of the Base.
The USAF has chosen the remedial action for OU-2 in accordance with the Comprehensive
Environmental Response, Compensation, and Liability Act (CERCLA), 42 U.S.C. Section
9601 et seq., as amended by the Superfund Amendments and Reauthorization Act (SARA) of
1986, Pub. L. No. 99-499, 100 Stat 1613 (1986), and, to the extent practicable, the National
Oil and Hazardous Substances Pollution Contingency Plan (NCP), Title 40 Code of Federal
Regulations (CFR) Part 300. Data were collected at OU-2 and analyzed in accordance with
KNINEW.ROD/12-15-92/F
1-1
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a Work Plan (IT, 1991a), Quality Assurance Project Plan (QAPP, IT, 1991b), and Field
Sampling Plan (IT, 1991c) approved by the U.S. Environmental Protection Agency (U.S.
EPA), Arizona Department of Environmental Quality (ADEQ), and Arizona Department of
Water Resources (ADWR).
The summaries and discussion presented in this ROD concerning the presence of chemical
contamination at OU-2, potential exposure, human health risks, and remedial alternatives
selected for site restoration are based on data extracted from three reports: "Final Proposed
Plan, Operable Unit 2, Williams AFB, Phoenix, Arizona, April 1992," "Final Feasibility
Study, Operable Unit 2, Williams AFB, Phoenix, Arizona, April 1992," and "Final Remedial
Investigation, Operable Unit 2, Williams AFB, Phoenix, Arizona, January 1992." These
reports were also the basis on which the USAF selected the proposed remedial alternative
and are available for review in the Administrative Record for Williams AFB.
The U.S. EPA and the State of Arizona concur with the selected remedy for OU-2.
1.3 Assessment of the Site
Releases of Jet Propulsion Fuel Grade 4 (JP-4) and aviation gasoline (A VGAS) have
contaminated soils and groundwater at OU-2. A variety of non-petroleum related CERCLA
hazardous substances were also detected in OU-2 soils and groundwater. Actual or
threatened releases of hazardous substances from this site, if not addressed by implementing
the response actions selected in this ROD, may present an imminent and substantial
endangerment to public health and the environment. Benzene, which is present in JP-4, is
the most prevalent and mobile of the contaminants at OU-2. Where benzene or JP-4 is
referred to in this ROD, all of the chemicals of potential concern exceeding action levels are
also included by reference and will be treated by the selected remedy.
1.4 Description of the Selected Remedy
The data gathered for OU-2 indicate that the concentration of contaminants present in the
surface soils (first foot of soil) do not require further action, but the concentration of
contaminants present in the subsurface soils (soils below one foot) to 25 feet in depth and in
the groundwater warrant further action. The JP-4 floating on and dissolved in the
groundwater will continue to contaminate groundwater for many years, as discussed in the
OU-2 RI Report, Section 5.0, Contaminant Fate and Transport. The subsurface soils below
the 25-foot depth have been placed in OU-3 for further investigation at a later date.
KN/NEW. ROD/12-1S-92/F
1-2
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The major actions of the selected remedy are:
. Free-phase product and groundwater will be extracted using an estimated series
of up to 2 horizontal or 16 vertical extraction wells. The exact number, type,
and location of wells will be determined during the reITiedial design phase as a
result of aquifer tests conducted after well ins~lations. There is approximately
0.65 to 1.4 million gallons of free-phase product floating on top of the aquifer.
Total fluids pumping will be conducted at estimated flow rates between 30 and
60 gallons per minute (gpm) from the shallow aquifer using the extraction wells
to maintain hydraulic control of the plume and to reduce contaminant
concentrations. There is approximately 170 million gallons of groundwater
contaminated with benzene above the drinking water action level of 0.005 mg/L.
. Fluids extracted from the ground will be passed through an oil/water separator
in order to capture all free-phase product prior to treatment of the water. Free-
phase product will either be reused by an approved vendor or disposed of at an
authorized off-site disposal facility.
. Pretreatment, as needed, of the extracted groundwater will be conducted (e.g.,
precipitation, flocculation, clarification, filtration, acid,treatment, etc.) to
remove solids that may potentially interfere with the treatment for contaminants.
The specific system specifications will be developed from treatability studies
conducted during the remedial design phase, if required.
. Pretreatment, as needed, of the extracted groundwater will be conducted (e.g.,
precipitation, flocculation, clarification, filtration, ion exchange, etc.) to reduce
the concentration of metals to action levels identified in Chapter 6.0 and
Appendix A of this document. Section 6.1.1 provides details for including this
treatment contingency. The detection of certain metals during the remedial
investigation may have been erroneous and additional sampling during the
remedial design phase will confirm or eliminate the need for this treatment.
Treatment system specifications will be developed from treatability studies
conducted during the remedial design phase, if this treatment is required.
. Treatment of the extracted groundwater will be provided by twin air stripping
columns in series to reduce volatile contaminant concentrations to action levels
identified in Section 6 and Appendix A of this document. Contaminant
concentrations in groundwater requiring treatment are identified in Chapter 6.0
and Appendix A. Treatment will achieve greater than 99 percent removal of
volatile contaminants. The columns will be 2.5 feet in diameter with 18 feet of
packing each and 500 cubic feet per minute (cfm) of air flow each.
. Posttreatment, as needed, of the extracted groundwater will be conducted (e.g.,
liquid-phase carbon adsorption) to reduce semi-volatile organic concentrations to
cleanup levels identified in Chapter 6.0 and Appendix A of this document.
Section 6.1.1 provides details for including this treatment contingency. The
KN/NEW.ROD/12-1S-92/F
1-3
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detection of cenain phthalate compounds during the remedial investigation may'
have been erroneous and additional sampling during the remedial design phase
will confmn or eliminate the need for this treatment. Treatment system
specifications will be developed from treatability studies conducted during the
remedial design phase, if this treatment is required.
.
Tre:'.~ groundwater will either be injected back into the shallow aquifer to
assist in maintaining hydraulic control and to avoid depletion of the aquifer or
will be discharged to the Base wastewater treatment plant for beneficial use on
the Base golf course. A number of factors will be evaluated to yield a decision
by Parties to the Federal Facility Agreement (FFA) to inject treated
groundwater back into the aquifer and/or to discharge the treated groundwater
into the Base sanitary sewer for beneficial use on the Base golf course. These
factors include, but are not limited to the following: (1) the results of aquifer
measurements made during a given remediation period; (2) the ability of
injection wells to accommodate the extraction rate; and (3) identified need for
irrigation of the Base golf course. Based on cwrent estimates, four injection
wells are planned. Their exact number, type, and location will be determined
during the remedial design phase.
.
Soil treatment of the first 25 feet of soil (54,000 cubic yards) using
bioenhanced soil vapor extraction (SVE) will be provided- Vapor-phase
nutrients will be introduced to enhance biodegradation of soil contaminants.
Other biological enhancements (introduction of aerobic microbes, anaerobic
microbes, aerophilic microbes, liquid-phase nutrients, enzymes, and etc.) may
be used if appropriate treatability studies or equivalent data are reviewed and
indicate that significant remedial benefits would be accrued.
.
SVE will be implemented using approximately 64 extraction wells, 32 passive
vent wells, a vacuum system to remove 500 cfm of air from wells, and a
nutrient addition system. Contaminant concentrations in soil requiring
treatment are identified in Chapter 6.0 and Appendix A. Bioenhanced SVE
will achieve greater than 94 percent reduction of benzene, and 64 percent
reduction of l,4-dichlorobenzene. The exact number of wells will be
determined during remedial design.
.
Treatment of SVE and air stripping emissions will be provided using fume
incineration to meet ambient air quality and destruction and capture
requirements. Treatment will achieve greater than 99 percent reduction of
benzene, 1,4-dichlorobenzene, naphthalene, and toluene. In the event that the
fume incinerator cannot technically achieve an acceptable emission level of less
than three pounds per day of organic vapors, then a vapor-phase carbon
adsorption unit will be installed and used instead of the fume incinerator.
Process details for these alternative air emission treatment systems include:
KN/NEW.RODI12-16-92AJF
1-4
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- Air stripping abatement by carbon - each stripping column would have dual-
bed, series adsorbers each containing 2,000 pounds of carbon with carbon
usage at 300 pounds/day
- Air stripping abatement by fume incineration - unit would be rated at 1.2
million British thermal units (BTU)/hr, 1000 cfm, with fuel usage at 33.6
million BTU/day
- SVE abatement by carbon - SVE system would have 2 dual bed systems with
each bed containing 11,000 pounds and using 6,800 pounds of carbon per
day in the first year, 1,500 pounds per day in the second year, and 1,200
pounds per day in the third year
- SVE abatement by fume incineration - unit would be rated at 0.6 million
BTU/hr, 500 cfm, with fuel usage at 11 million BTU/day in the first year,
5.5 million BTU/day for the second and third years.
. Institutional activities will be taken to impose restrictions on installation of new
wells and limiting soil excavation to 10 feet in depth at the ST -12 site.
This remedy will include adding several new groundwater monitoring wells to evaluate the
extraction system effectiveness in containing and remediating contaminants in the groundwa-
ter. It will also require soil monitoring to evaluate the removal of contaminants from the
soils.
1.5 Declaration
The selected remedy for OU-2 is protective of human health and the environment, complies
with Federal and State requirements that are legally applicable or relevant and appropriate to
the remedial actions, and is cost-effective. The OU-2 remedy utilizes permanent solutions
and alternative treatment or resource recovery technologies to the maximum extent
practicable and satisfies the statutory preference for remedies that employ treatments to
reduce toxicity, mobility, or volume as principal elements.
This remedy is part of a larger Base-wide remedial action and is consistent with such an
action. Additional operable units will be designated to fully address other areas of potential
contamination at the Base. The USAF is conducting remedial investigations at Williams
AFB to determine the presence and extent of contaminants and will be developing final
remedial alternatives for Base-wide remedial action. Because hazardous substances will
remain on-Base above health-based levels while groundwater and soil treatment occurs at
OU-2, a review will be conducted within 5 years after commencement of the remedial
KN/NEW.RODI12-1 S.92/F
1-5
-------
actions selected in this ROD to ensure the remedy continues to provide adequate protection
of human health and the environment.
KN/NEW. RODIl2-1S-92/F
1-6
-------
This Record of Decision for Operable Unit Number Two at Williams Air Force Base,
Arizona may be executed and delivered in any number of counterparts, each of which
when executed and delivered shall be deemed to be an original, but such counterpans
shall together constitute one and the same document.
1 5DEC 1992
Date
Roger Alexander, Colonel, USAF
Commander, 82nd Flying Training Wing
Date
John C. Wise, Deputy Regional Administrator
U.S. Environmental Protection Agency, Region IX
Date
Ed Fox, Director
Arizona Department of Environmental Quality
Date
Elizabeth A. Rieke, Director
Arizona Department of Water Resources
Date
-------
.:~ I ~.-' r.
6029883338
P.82
This Record of Decision fl)' i )p~~abll l)nil Number Two at Williams Air Force Base,
Arizona may be executed and deli...er('(i '11 any number of counterpart~, each of which
when executed and deliverc-d ,ha1l bt dn:med to be an original, but such counterparts
shall together constitute on, :\lJd th~' "ame document.
Eugene E. Habiger, Major General. USAf
Vice Commander. Air Training Command
Date
~A .~"-.
Roger ~exander, Colonel, 11SAF
Commander, 82nd Flying TralIlln~ \Virl~
IS~'t,-
Date
John C. Wise, Deputy Regit\l,a! Admim~tralor
U.S. Environmental Protectllll: >\gem)'. Region IX
Date
Ed Fox, Director
Arizona Department of Environmenral Quality
Date
Elizabel;1 A Rieke, Directol
Arizona Department of Water Resource~
Date
. -..--.. . ...--.
-------
This Record of Decision for Operable Unit Number Two at Williams Air Force Base,
Arizona may be executed and delivered in any number of counterpans, each of which when
executed and delivered shall be deemed to be an original, but such counterpans shall together
constitute one and the same document.
Eugene E. Habiger, Major General, USAF
Vice Commander, Air Training Command
Date
Roger Alexander, Colonel, USAF
Commander, 82nd Flying Training Wing
Date
&'
C.w~
Jon. Wise, Deputy Regional Administrator'
U. S. Environmental Protection Agency, Region IX
12.30. 'IL..
Date
Ed Fox, Director
Arizona Depanment of Environmental Quality
Date
Elizabeth A. Rieke, Director
Arizona Department of Water Resources
Date
KJI: It'EW. ROD/12-15-92/F
1-7
-------
1-"
This Record of Decision for Operable Unit Number Two at Williams Air Force Base,
Arizona may be executed and delivered in any number of counterpans, each of which when
executed and delivered shall be deemed to be an original, but such counterpans shall together
constitute one and the same document.
Eugene E. Habiger, Major General, USAF
Vice Commander, Air Training Command
Date
Roger Alexander, Colonel, USAF
Commander, 82nd Flying Training Wing
Date
John C. Wise, Deputy Regional Administrator
U.S. Environmental Protection Agency, Region IX
Date
/~/2 ~ifL
Date
ment of Environmental Quality
Elizabeth A. Rieke, Director
Arizona Department of Water Resources
Date
KNfNEW.ROD/12-1S-92fF
1-7
-------
This Record of Decision for Operable Unit Number Two at Williams Air Force Base,
Arizona may be executed and delivered in any number of counterpans, each of which when
executed and delivered shall be deemed to be an original, but such counterpans shall together
constitute one and the same document.
Eugene E. Habiger, Major General, USAF
Vice Commander, Air Training Command
Date
Roger Alexander, Colonel, USAF
Commander, 82nd Flying Training Wing
Date
John C. Wise, Deputy Regional Admin"istrator
U.S. Environmental Protection Agency, Region IX
Date
Ed Fox, Director
Arizona Department of Environmental Quality
Date
/2/5/ hL
Elizabeth A. Rieke, ir tor
Arizona Department of Water Resources
Date
KN INEV.'. RODII2-1S-92IF
1-7
-------
2.0 Decision Summary
2. 1 Site Name, Location, and Description
Williams AFB is a flight training base located in Maricopa County, Arizona approximately
30 miles southeast of Phoenix and just east of Chandler (See Figure 2-1). The Base,
commissioned as a flight training school, was constructed on 4,127 acres of government land
in 1941. There are runway and airfield operations, industrial areas, housing, and
recreational facilities on the Base. Training acrivities started after construction with jet
aircraft training starting in 1949. The Base is currently active, but Base closure is
programmed for the future.
This ROD addresses remedial actions for OU-2, which is a partially decommissioned LFSA
(ST-12) on Williams AFB covering approximately 4.4 acres (Figure 2-2). The OU-2 RI
focused primarily on approximately 2.8 acres in the vicinity of distribution lines and tanks
where A VGAS and JP-4 spills and leaks have occurred. A portion of the 2.8 acres
investigated lies beyond the surface boundary of OU-2 shown in Figure 2-2 due to the aerial
extent of the groundwater contaminant plume.
Williams AFB is relatively isolated from any large metropolitai; area - it is surrour,ded
primarily by agricultural land. This land lies in a valley that has had a long history of
intensive agricultural use, predominantly for crops of citrus, cotton, and alfalfa. Smaller
urban areas such as Mesa, Chandler, Gilbert, and Apache Junction are located 5 to 15 miles
northeast and northwest of the Base. The Queen Creek and Chandler Heights areas are
approximately 5 miles south and west of : ..~ Base boundary. Table 2-1 lists these towns and
others by distance and direction from Wiliiams AFB. These areas are separated from the
Base by cultivated and uncultivated land.
There are 3,029 military personnel and 869 civilian employees stationed at the Base. Many
of the military personnel live off Base in one of the surrounding areas. The total population
actually living on Base, including dependents, is approximately 2,700. On an average
workday, Ule population of the Base increases to more than 5,000 because of the influx of
both civilian employees and military personnel who live off base (Cost Branch Controller
Division, 1987).
KN INEW.RODI12-1 S-92/F
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PRIMARY ROADS
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SlRUClURE
FACIU1Y NUMBER
557
-x-x. FENCE
----- BOUNDARY OF" ST-12 (OU-2)
-.. -.. - ruEL DISTRIBUTION LINES
SCALE:
I
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---..
200
I
400 FEET
RGURE 2-2
WIlliAMS AIR FORCE BASE
SITE MAP
OPERABLE UNIT 2
III mTERNATIONAL
TECHNOLOGY
CORPORATION
-------
Table 2-1. Cities Surrounding Williams AFB
Distance from
City Direction Relative to WAFS WAFS (miles) Population.
Apache Junction North Northeast 10 18,100
Chandler West 10 90,533
Gilbert Northwest 5 29,1 88
Mesa North Northwest 15 288,091
Queen Creek South 5 2,667
Tempe Northwest 20 141 ,865
Phoenix Northwest 30 893,983
.April 1, 1990 Census, Public Law Tape 94-171.
ICN/NEW.2N12-11-92/F
-------
A development plan for the region (Sunregion, 1987), if implemented, will dramatically alter
the region surrounding Williams AFB. The portions of the development plan of most
importance to the Base are the East Mesa Subarea Plan and the Queen Creek-Chandler
Heights Plan. The former proposes development for portions of the City of Mesa, the Town
of Gilbert, the City of Apache Junction, and the land area north of Williams AFB. The
proposed land area for the Queen Creek-Chandler Heights Plan is east of Chandler, just
south of the Base in the approximate location of the Town of Queen Creek. The plan is to
develop the proposed area residentially and commercially for a 25-year period. If
implemented, this development will dramatically impact the demographics and population
around the Base. In addition, Williams AFB is currently scheduled for closure, and this
action could also impact the region.
This development plan may be altered by the recommendations of a noise exposure and land
use compatibility study sponsored by the Maricopa Association of Governments (MAG)
(Barnard Dunkelberg & Company, 1988). After analysis of existing and projected noise
contours resulting from Base operations, recommendations were made for mitigating noise
impacts in the area. These recommendations will preclude new residential development
within 1 to 4 miles beyond the east, southeast, and northwest boundaries of the Base.
Restricted development is recommended for areas within 1 to 6 miles beyond the boundary of
the Base in all directIOns; however, land use limitations due to noise impacts within these
areas will be lifted if Base closure occurs and flight operations at the Base end.
There are no major surface water bodies within a lO-mile radius of the Base. The Base lies
between the loo-year and 5OO-year flood level for streams in the Gila River Basin (U.S.
Department of Housing and Urban Development, 1979). Storm drainage on the Base is
directed to a combination of open channels used to drain most of the Base and underground
drainage structures. Storm drainage from the Base flows either to the Roosevelt Water
Control District (RWCD) flood way that flows southward in the vicinity of the Base or
directly to the floodway west of the Base, or into the wastewater treatment plant. OU-2 does
not connect to the storm runoff ditch systems at the Base.
There are at least 90 domestic permitted wells within a 3-rnile radius of the Base. These
wells are not affected by the contamination at OU-2. The Base currently performs quarterly
monitoring of wells on the Base in the vicinity of OU-2.
KN/NEW.ROD/12-1S.92/F
2-2
-------
The climate of Williams AFB is similar to that of Phoenix and the rest of the Salt River
Valley. The temperature ranges from very hot in the summer to mild in winter. Rain comes
mostly in two seasons - from late November until early April and in July and August.
A verage annual precipitation is approximately 7.1 inches. Humidities range from approxi-
mately 30 percent in winter to 10 percent in summer. Williams AFB is also characterized by
light winds. Evapotranspiration rates in the area exceed -65 inches per year.
Williams AFB lies in the eastern ponion of the Basin and Range Physiographic Lowlands
Province of south central Arizona, which is located in the Salt River Valley. The local
topography is controlled by large-scale normal faulting that has resulted in the formation of
broad, flat, alluvial-filled valleys separated by steep isolated hills and mountain ranges.
ADWR's hydrologic maps show the Base bounded to the north by the Usery Mountains, to
the east by the Superstition Mountains, to the south by the Santan Mountains, and to the west
by South Mountain.
The topography of the Base slopes gently to the west with a generally less than 1 percent
grade. Elevations range from 1,326 feet above mean sea level (msl) on the west side of the
Base to 1,390 feet above msl at the southeast comer of the Base.
According to Laney and Hahn (1986), the area of the Base is underlain by six geologic units:
crystalline rocks, extrusive rocks, red unit, lower unit, middle unit, and upper unit. The
crystalline and extrusive rocks comprise the surrounding mountains and the basement
complex underlying the consolidated and unconsolidated sediments of the valley. The four
units overlying the basement complex are of sedimentary origin and have the surrounding
mountains and local drainage as their source areas.
The red unit immediately overlies the basement complex and is composed of well-cemented
breccia, conglomerate, sandstone, and siltstone of continental origin with interbedded
extrusive flow rocks.
The lower unit overlies the red unit and consists of playa, alluvial fan, and fluvial deposits
with evaporites and interbedded basaltic flows present in lower sections (Laney and Hahn,
1986).
KN/NEW. ROD/12.15-92/F
2-3
-------
The middle unit overlies the lower unit and is composed of playa, alluvial. fan, and fluvial
deposits with no associated evaporites. The middle unit received its sediment primarily from
the Salt River, whereas the lower units had the local mountains as the principal source.
The youngest unit in the stratigraphic sequence is referred to as the upper unit. The unit
consists of channel, floodplain, terrace, and alluvial fan deposits of larg~iy unconsolidated
gravel, sand, silt, and clay.
Geological conditions beneath OU-2 were characterized by using a combination of continuous
coring and geophysics. The deposits encountered during drilling at OU-2 are correlative to
the upper unit of Laney and Hahn (1986) and possibly to the extreme upper section of their
middle unit.
There are two major soil associations found in the vicinity of Williams AFB. The Mohall-
Contine Association is found over much of the Base, and the Gillman-Estrella-A vondale
Association is found at the southern boundary of the Base. The Mohall-Contine and the
Gillman-Estrella-Avondale Associations have generally the same characteristics, being well
drained and nearly level with slopes of less than 1 percent.
Because of a decline in the water table produced by excessive irrigation withdrawals over the
past 50 years, an extensive vadose zone has been produced in the vicinity of Williams AFB.
Presently beneath OU-2, the vadose zone extends to approximately 220 feet below ground
surface (the depth to the water table). The low rainfall and high evapotranspiration rate of
the area result in a very low potential for recharge to occur through the soil comprising the
vadose zone. To the west and south of the Base, extensive irrigation results in a potentially
significant amount of recharge to the uppermost aquifer through these sediments.
The hydrogeology of the sediments investigated immediately beneath ST -12 is characterized
by the presence of two unconnected saturated zones. Only the uppermost aquifer is included .
in OU-2 because the deep aquifer has not been affected by the contamination. Although
these two saturated zones are not connected beneath OU-2, they are part of a thick mu1ti-
aquifer system that is interconnected to various degrees in a broader geographical
perspective. Beneath the uppermost saturated zone is a very low permeability, laterally
extensive, fine-grained layer approximately 20 feet thick. This layer is interpreted as the
lower confining layer for the uppermost saturated zone.
KN/I' i:"W. ROD/12-IS-92IF
2-4
-------
Groundwater flow in both aquifers is predominantly to the east and southeast.
2.2 Site History and Enforcement Activities
Williams AFB is a flight training base that opened in 1942. It was immediately commis-
sioned as a flight training school and training activities with jet aircraft were started in 1949.
Throughout its history, pilot training has been the primary activity at Williams AFB. At
various times, bombardier, bomber pilot, instrument bombing specialist, and fighter gunnery
training schools were also housed on Base. Over the years, a wide variety and large number
of aircraft have been based at Williams AFB, including the current training aircraft, the T-37
and T-38.
2.2. 1 Site History
Liquid fuels have been stored at OU-2 since 1942. Primary storage was in a series of
underground storage tanks (UST) at Facilities 688, 514, 538, and 548. Aboveground storage
tanks located at Facilities 556 and 557 were constructed in 1962 and 1954, respectively.
OU-2 was investigated because of fuel leaks and the age of the system. It was closed in
August 1988 except for the aboveground tanks at Facilities ~56 and 557. During late 1990
and early 1991, fourteen underground tanks at Facilities 688, 514, 538, and 548 were re-
moved along with the distribution lines leading to them. In addition, 5 steel tanks were
discovered and removed, bringing the total to 19 underground tanks.
Eight soil borings were installed by AeroVironment, Inc. (A V) in 1984. During the next
phase of the investigation in 1986, soil organic vapor (SOV) surveys were conducted along
distribution lines and near buried tanks to determine if there was evidence of leakage.
Thirty-eight soil borings were then installed by A Vasa result of the SOY survey.
IT Corporation (IT) completed two SOY surveys in 1989, collecting and analyzing 52 vapor
samples. The results of these surveys were used to establish the location of five soil borings'
that were installed to collect subsurface soil data in 1989. Ten surface soil samples were
collected and analyzed in August 1991 to further characterize OU-2. The soil boring and
SOY survey locations are shown in Figure 2-3.
Thirty-six groundwater monitoring wells had been installed at OU-2 as of October 1991. An
initial groundwater sampling round was performed by A V, followed by subsequent
groundwater sampling by IT. During the period groundwater sampling was performed,
KN/NEW.ROD/12-1S-92/F
2-5
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NOTES:
1. SOIL BORINGS NOT INSTALLED: No.8 STAGE 1 & NO. SS01-B-05
2. ALL SOY PROBE LOCATIONS ARE APPRQXIMA TE.
3. ALL SOY PROBE LOCATIONS MADE AT APPROXIMA TEL Y 5'
FROM PIPE, IF SOY DETECTED 5' TO EAST AND 5' TO
NORTH OR SOUTH, .
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AREA OF PAST LEAKS - AV
~ SOY SURVEY AREA - IT
4
IT SOY PROBE LOCA TlON
AV STAGE 1 SOIL BORING
AV STAGE 2 SOIL BORING
IT SOIL BORING
.
.
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FUEL DISTRIBUTlON LINE
FIGURE 2-3
WILLIAMS AIR FORCE BASE
SOIL BORING AND SOY SURVEY
LOCATIONS
r'1:":I ~ATlONAL
ULJI c0RP8~TI<&\
-------
floating free-phase product was measured in monitoring wells. The free-phase product
thickness varied from a sheen to approximately 15 feet in 5 monitoring wells. The location
of the monitoring wells are shown in Figure 2-4.
Results of these historical sampling activities can be found in Section 4.0.
2.2.2 Enforcement Activities
Installation Restoration Program (IRP) guidance was received for Williams AFB in July 1983
and the initial assessment study was completed by Engineering-Science (ES) in 1984. Based
on a review of available records pertaining to chemical handling and disposal practices,
interviews with site personnel, and a site survey of activities at Williams AFB, several
potential sites where hazardous materials had been handled or disposed were identified.
A V performed an investigation from September 1984 to December 1985, which was initiated
to confirm the information in the ES report and to verify the presence and quantify the extent
of contamination. In 1987 A V completed an additional investigation to define the most likely
pathways for contaminant migration from each site and to confirm the presence or absence of
contamination along those pathways.
In October 1988, the Air Training Command (ATC) contracted Martin Marietta Energy
Systems, Inc. (Energy Systems) and its subcontractor, IT, to complete the OU-2 RI/FS,
proposed plan, and ROD at Williams. AFB. These actions were initiated later in 1988.
Williams AFB was added to the NPL on November 21, 1989. As a consequence of
inclusion on the NPL listing, negotiations were initiated and completed on a FFA for
Williams AFB, which was signed on September 21, 1990 by the U.S. EPA, USAF, ADEQ,
and ADWR (U.S. EPA, 199Gb).
2.3 Highlights of Community Participation
A community relations plan for the Base was finalized in February 1991 (IT, 1991d). This
plan lists contacts and interested parties throughout the USAF, government, and local
community. It also established communication pathways to ensure timely dissemination of
pertinent information through mailings, public announcements in the local paper, and local
information repositories.
KN/NEW.ROD/12-15-92/F
2-6
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~ MONITOHING WELL LOCATION AND NUMBER
SSO I-W-15
fiGURE 2-4
WILLIAMS AIR FORCE BASE
LIQUID FUELS STORAGE AREA
MONITORING WELL NETWORK
(0) DEEP MONITOI~ING WELL
SCALE:
o
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250 500 fEET
L__J
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INTERNATIONAL
TECHNOLOGY
CORPORATION
-------
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The OU-2 RIfFS was released for public review in May of 1992. This was followed by
announcement in the Arizona Republic/Phoenix Gazette of the issuance of an OU-2 proposed
plan for public comment and a public meeting. The 3D-day public comment period on the
proposed plan began on June 1, 1992, and the public meeting was held on June 16, 1992 in
the City of Mesa, Arizona, to discuss the proposed groundwater and soil cleanup
alternatives. All comments received during the public comment period are included in the
Responsiveness Summary (Chapter 10.0), which also includes a response prepared by the
USAF.
Technical Review Committee meetings are held periodically with representatives of the
USAF, regulatory agencies, and the community. The meetings provide a forum for members
of the community serving on this committee to be involved in decisions regarding
investigation and Base cleanup activities.
An Administrative Record that contains the documents relating to investigations and cleanup
activities proposed for the Base has been established and is available for public inspection at
the Chandler and the Williams AFB Libraries. Additional information .is available through
the Williams AFB Public Affairs Office.
KN/NEW. ROD/12-15-92/F
2-7
-------
3.0 Scope and Role of Operable Unit
Currently three operable units have been identified at the Base. The groundwater and soil to
a depth of 25 feet at ST-12 cmprise OU-2. Groundwater and soil2.! 12 of the 13 other
areas of the Base comprise O. The contaminated sc: below 25 ..~et at ST-12 and
groundwater and soil at the remaining area will be addressed in OU-3. OU-2 is addressed by
this ROD while the remainder of the sites will be addressed in the OU-l and OU-3 RODs.
The Base-wide remedy will be addressed in the Base-wide OU-3 ROD.
The principal potential risk to human health and the environment at OU-2 is from IP-4
contamination of groundwater. Delays in remediating the groundwater in the upper aquifer
could potentially allow contamination to spread to a deeper aquifer, making remediation more
difficult and costly. Another potential risk to human health and the environment is from JP-4
contamination of soil to a depth of 25 feet at OU-2.
Data have shown that chemical-specific applicable or relevant and a.ppropriate requirements
(ARAR), Arizona Health-Based Guidance Levels (HBGL) for soil, or other risk-based levels
to be considered have been exceeded in the groundwater and the first 25 feet of soils at OU-
2. Because of thi' _he groundwater and top 25 feet of soil at ST-12 was designated as an
operable unit to more responsively initiate action to mitigate potential threats to human health
and the environment. The remedy selected in this ROD is designed to be consistent with any
subsequent remedies and planned future actions at the Base proposed in all subsequent RODs.
KNINFW.RODf12-15-92fF
3-1
-------
4.0 Summary of Site Characteristics
Based on investigations that began in 1984 and continued through February 1992, a number
of contaminants were detected in both the first 25 feet of soil and in the groundwater at ST-
12 (also called OU-2). The occurrence of these chemicals are summarized in Table 4-1
through 4-4. The soils below 25 feet at ST-12 are not included in OU-2 and will be
addressed at a future date as part of OU-3.
The OU-2 RI data document releases of petroleum products to the environment from
underground pipelines and tanks at OU-2. The pri~cipal environmental concerns at OU-2 are
'associated with (1) jet fuel constituents that remain in the top 25 feet of soil, and (2) jet fuel
constituents that have migrated into the groundwater.
The remainder of this section summarizes the chronology and findings of remedial
investigations at OU-2. Potential routes of exposure and risks to human health and the
environment from the contaminated soil and groundwater are summarized in Chapter 5.0.
Detailed presentations of both the findings of the remedial investigation and the risk
assessment can be found in the OU-2 RI report. Applicable or relevant and appropriate
requirements (ARAR) and other criteria to be considered (TBC) are presented in Appendix
A. Taken together, Chapters 4 and 5 and Appendix A establish the comprehensive list of
chemicals of potential concern for surface soil, subsurface soil, and groundwater at OU-2 and
their respective action levels. Chapters 6, 7, and 8 detail the FS, including the alternatives
considered, and present the selected remedy.
4. 1 Soil Contamination
Soil investigations at OU-2 unfolded in essentially four stages. The first two phases were
conducted by A V in 1984 and 1986. The last two stages were conducted by IT in 1989 and
1991.
Chemicals and metals were detected in the first 25 feet of soil at OU-2. Subsurface (Le.,
below 1 foot in depth) soil samples from eight borings installed by A V in 1984 showed levels
of total organic halogens (TOX), oil and grease, lead, and phenol above detection limits or
above generally considered background levels. During the next phase of the investigation in
1986, SOY surveys were conducted by A V along distribution lines and near buried tanks to
determine if there was evidence of leakage. Nine areas, five exhibiting levels of benzene,
KNfNEW. RODf12. 15.92fF
4-1
,
-------
Table 4-1. Chemicals Identified in Subsurface. Soil at OU-2 by AeroVironment
Frequency of Range of Detected
Constituent Detection b Concentrations
(ppm)
Organics
Benzene 1 7/69 2.0 - 730.0
Chlorobenzene 4/69 27.0 - 300.0
1 ,2-Dichlorobenzene 19/69 2.0 - 140.0
1,3-Dichlorobenzene 12/69 2.0 - 130.0
1 A-Dichlorobenzene 20/69 2.0 - 180.0
Ethyl Benzene 23/69 1.0 - 410.0
Toluene 23/69 2.0 - 1,200.0
Xylenes (total) 24/69 4.0 - 1,500.0
Total Petroleum Hydrocarbons
TPH 26/68 220.0 - 88,000.0
Metals
Lead 89/106 5.0 - 1, 1 00.0
Soil 1 foot or more below the surface is considered subsurface.
If the concentration of the detected chemical is less than ten (for common
laboratorycontaminants) or five times the concentration found in any blank, the
chemical was not considered a detection.
KN/NEW.4A/12-' 1-92/F
-------
Table 4-2. Chemicals Identified in Subsurface. Soil at OU-2 by IT
Range of Detected Range of
Frequency of Concentrations Background C
Constituent Detection b (mg/kg) (mg/kg)
Organics
Acetone 4/4 0.003 - 0.91
Benzo(a)anthracene 1/4 7.8
Bis(2-ethylhexyl) phthalate 3/4 3.1 - 16.0
Bromoform 1/4 3.9
4-Chlorophenyl ether 1/4 0.13
1 ,2-Dichloroethane 1/4 0.91
1 ,1-Dichloroethylene 1/4 0.74
Methylene Chloride 4/4 0.017 - 0.47
Styrene 1/4 8.1
T etrachlorotehylene 1/4 1.4
l,2,4-Trich/orobenzene 1/4 4.7
Vinyl Acetate 1/4 7.7
Xylenes (total) 1/4 40.0
Total Petroleum Hydrocarbons
TPH 1/4 3.850
Metals
Antimony 4/4 20.0 - 48.0 1.0
Arsenic 2/4 2.0 - 3.0 0.65 - 6.5
Chromium 4/4 12.0-16.0 30.0 - 500.0
Copper 4/4 21.0 - 28.0 30.0 - 200.0
Lead 4/4 4.6 - 15 15.0 - 150.0
Nickel 3/4 13.0 . 19.0 15.0 - 200.0
Zinc 4/4 41.0-73.0 74.0 - 510.0
NA = Background data are not available for these metals.
Soil 1 foot or more below the surface is considered subsurface.
If the concentration of the detected chemical is less than ten (for common laboratory contaminants) or
five times the concentration found in any blank, the chemical was not considered a detection.
Background concentrations for the Phoenix area taken from "Element Concentrations in Soils and Other
Surficial Materials of the Conterminous United States," USGS Geological Survey Professional Paper
1270, 1984.
KNINEW.4BI' 2.' '-92IF
-------
Table 4-3. Chemicals Identified in Surface Soil at OU-2 by IT
Range of Detected
Frequency of Concentrations Range of Backgroundb
Constituent Detection' (ppm) (ppm)
Organics
Acetone 7/10 0.002 - 0.033
Anthracene 1/10 0.022 0.011 - 0.013-
Benzo(a)anthracene 1/10 0.15 0.056 - 59.000
Benzo(a)pyrene 2/10 0.028 - 0.165 0.0046 - 0.900
Benzo(b)fluoranthene 4110 0.031 - 0.180 0.058 - 62.000
Benzo(g,h,i)perylene 1/10 0.035 0.066 - 47.000
Benzo(k)fluoranthene 2/10 0.073 - 0.170 0.058 - 26.000
Bis(2-ethylhexyl)phthalate 9/10 0.037 - 0.960
2-Butanone 1/10 0.015
Butylbenzylphthalate 1/10 0.037 - 0.165
Carbazole 1/10 0.063
Chrysene 4/10 0.020 - 0.410 0.078 - 0.640
Diethylphthalate 2/10 0.026 - 0.165
Di-n-butylphthalate 2/10 0.025 - 0.165
Di-n-octylphthalate 1/10 0.0210
Fluoranthene 3110 0.029 - 0.270 0.120 - 166.000
2-Hexanone 1/10 0.011
Indeno( 1 ,2,3-c,d)pyrene 2/10 0.026 - 0.165 0.063 - 61.000
4-Methyl-2-Pentanone 1/10 0.005
Phenanthrene 5110 0.027 - 0.165 0.048 - 0.140-
Pyrene 4/10 0.043 - 0.360 0.099 - 147.000
Total Petroleum Hydrocarbons
TPH 1110 0.012
Metals
Arsenic 1 0/1 0 2.3 - 6 0.65 - 6.5
Beryllium 10/10 2.2 - 3.5 1.0 - 1.5
Cadmium 10/10 1.4 - 2.8 NA
Chromium 1 011 0 15.3 - 25.5 30.0 - 500.0
Copper 10/10 22.7 - 45.5 30.0 - 200.0
Lead 1 0/1 0 19.5 - 76.5 15.0 - 150.0
Nickel 10/10 15.5 - 27.6 15.0 - 200.0
Zinc 10/10 70 - 101 74.0 - 510.0
If the concentration of the detected chemical is less than ten (for common laboratory contaminants) or five times
the concentration found in any blank, the chemical was not considered a detection.
Background concentrations for PAHs for agricultural and urban soils taken from WDraft Toxicological Profile for
Polycyclic Aromatic Hydrocarbons", ATSDR, 1989. Ranges with. are from agricultural soils only, no urban values
were available. Background concentrations of metals for the Phoenix area taken from wElement Concentrations
in Soils and Other Surficial Materials of the Conterminous United States, W USGS Geological Survey Professional
Paper 1270, 1984.
KN/NEW.4C/12-11-92/F
-------
Table 4-4. Chemicals Identified in Groundwater Monitoring Wells at OU-2
(Page 1 of 2)
IT Investigations A V Investigations
Constituent Range of Detected Range of
Frequency of Concentrations Frequency of Detected
Detection' (mg/L) Detection' Concentration
(mg/L)
Organics
Acetone 1/69 0.033
Benzene 104/133 0.0006 - 24.0 5/9 0.0014 - 12~0
Bis (2 -ethyl he xyl) phthal ate 8/76 0.002 - 0.028
Bis( 2 -chloroethyl)ether 1/76 0.140
Chlorobenzene 1/9 0.0006
Dibenzofuran 1/76 0.300
1 A-Dichlorobenzene 1/9 0.0036
1,2-Dichloroethane 3/77 0.0008 - 0.016
2A-Dimethylphenol 4/76 0.002 - 0.015
Ethyl Benzene 55/133 0.0005 - 3.5 4/9 0.0011 - 2.8
Methylene Chloride 3/77 0.260 - 0.282
2-Methylnaphthalene 10/76 0.006 - 10.0
2-Methylphenol 6/76 0.002 - 0.14
4-Methylphenol 4/76 0.006 - 0.073
Naphthalene 15/77 0.004 - 7.2
2-Nitrophenol 1/76 0.017
4-Nitrophenol 2n6 0.008 - 0.018
Phenol 13/76 0.011 - 0.18
Tetrachloroethene 3/70 0.005 - 0.0012
Toluene 24/133 0.086 - 24.0 4/9 0.048 - 21.0
1 ,1 , 1- Trichloroethane 1/77 0.0008
T richlorofluoromethane 4/77 0.0007 - 0.0022
Xylenes (total) 78/1 33 0.0006 - 9.8 4/9 0.016 - 5.9
KN/NEW.4D/12.11.92/F
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Table 4-4. Chemicals Identified in Groundwater Monitoring Wells at OU-2
(Page 2 of 2)
IT Investigations A V Investigations
Constituent Range of Detected 1 Range of
Frequency of Concentrations Frequency o-: ! Detected
Detection' (mg/L) Detection' i Concentration
(mg/L)
Total Petroleum Hydrocarbons
TPH 71/175 0.6 - 80,000.0
Metals
Antimony 5/75 0.012 - 0.433
Arsenic 4n5 0.0013 - 0.0015
Beryllium 1/75 0.0085
Cadmium 3n5 0.018 - 0.030
Chromium 21n5 0.0042 - 54.5
Copper 14/75 0.0085 - 0.5
Lead 17/75 0.0011 - 0.079 6/10 . 0.004 - 0.017
Mercury 6/76 0.00012 - 0.17 b
Nickel 20/75 0.010 - 4.99
Selenium 5/76 0.02 - 0.04
Silver 7n5 0.0029 - 0.111
Uranium 4/10 0.002 - 0.005
Zinc 50n5 0.0059 - 3.969
. If the concentration of the detected chemical is less than ten (for common laboratory contaminants) or
five times the concentration found in any blank, the chemical was not considered a detection.
b Mercury was also detected in an associated blank for this sample. The highest concentration detected
in a sample without blank contamination was 0.0018 mg/L.
KN/NEW.4D/12-11-92/F
-------
toluene, ethyl benzene, and xylene (BTEX) above detection levels, were identified by A V as
indicating possible leaks in lines and tanks. Subsurface soil samples from the first 25 feet of
soil from some of the 38 soil borings installed by A V showed levels exceeding detection
limits for nine organic chemicals, heavy metals, and total petroleum hydrocarbons (TPH)
(Table 4-1). Most borings were drilled to less than 50 feet, but one drilled to 210 feet
detected contamination throughout its entire depth.
IT completed two SOY surveys in 1989, collecting and analyzing 52 vapor samples.
Readings near Facility 555 above detection levels led to the discovery of a leak in a
distribution line. The results of these surveys guided the location of five borings that were
installed by IT to a maximum depth of 100 feet. Twenty-four organic chemicals, heavy
metals, and TPH were detected in subsurface soil samples taken from these borings (Table
4-2).
Ten surface soil samples were collected and analyzed in August 1991 by IT. The results of
these surface soil analyses indicate that the fuel-related contamination is not generally present
at the surface. Table 4-3 shows the 29 organic chemicals, heavy metals, and TPH that were
detected in surface soil samples collected by IT, along with ranges of background
concentrations. Note that results are either below action levels identified in Appendix A,
Table A-2, or within background ranges. The results of the 4 phases of soil investigations
allowed the areas of possible soil contamination to be delineated near Facility 548, along the
fuel distribution line near Facility 555, along the distribution line southwest of Facility 514,
and at Facility 688. Using cleanup levels established in Appendix A, Table A-4, the
contamination found in OU-2 soils is estimated to be approximately 54,000 cubic yards of
contaminated soils in four areas as shown in Figure 4-1.
4.2 Groundwater Contamination
Thirty-six monitoring wells (both shallow and deep) have been installed at OU-2 as of
February 1992. Organic vapors were detected during the installation of several of these
wells, which, in one instance, led to locating a leak in a distribution line near Facility 514.
Eight organic chemicals and metals were detected in initial groundwater sampling by A V; 33
organic chemicals, metals, and TPH were detected in subsequent sampling by IT. A
groundwater sampling data summary is provided as Table 4-4, which includes TPH and 36
organic chemicals and heavy metals as chemicals identified by A V and IT in the groundwater
monitoring wells at OU-2.
KN/NEW.RODII2-IS-92/F
4-2
-------
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- . . - . . - FUEL DISTRIBU110N LINES
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FIGURE 4-1
WILLIAMS AIR F"ORCE BASE
AREAS OF SOIL CONTAMINATION
AT OU-2
III INTERNATIONAL
TECHNOLOGY
CORPORATION
-------
Floating free-phase product was measured in five of the wells sampled, varying from a sheen
to a thickness of approximately 15 feet. The estimated extent of the free-phase floating JP-4
plume beneath OU-2 is shown in Figure 4-2 based on measured product in July 1991 and
modeling. The magnitude of the free product plume has been estimated to be between
650,000 and 1,400,000 gallons.
The estimated extent of the dissolved plume also shown on Figure 4-2 is based on July 1991
benzene concentration data. The extent of the plume delineated at less than 5 parts per
billion (Ppb) in all directions has' not been estimated at this time. The dashed line on the
figure indicates the areas of uncertainty in the plume boundary. Benzene was chosen as an
indicator for defining the boundary of the groundwater contamination plume because it poses
the greatest danger to human health and the environment of the organic chemicals and heavy
metals that were detected in groundwater at OU-2. The 5 ppb level is the drinking water
standard for benzene promulgated by the National Primary Drinking Water Regulations. The
volume of contaminated groundwater within the 5 ppb line is approximately 170 million
gallons.
4.3 Contaminant Fate and Transport
Contaminant fate and transport was addressed in the OU-2 RI report, Section 5.0.
synopsis is presented below.
A brief
4.3. 1 Chemical Persistence
The f!1obility of organic compounds within the saturated zone is affected by chemical
processes that are in part dependent on their volatility, the octanol-water partitions coefficient
(Kow), the water solubility, and the concentration. In general, the more water insoluble an
organic compound is, the more hydrophobic it is and the more likely it is to be absorbed on
a sediment or organic surface. These compounds also have a tendency toward self-
association in a polar medium such as water. Hydrophobic compounds tend to have a higher
Kow and a greater affinity to organic matter contained within the sediment matrix.
Compounds such as benzene with high aqueous solubilities have relatively low Kows.
Migration of these compounds tends to be more rapid than compounds such as phthalate,
pesticides, or large aromatic compounds that have low solubilities and high Kows. Even
compounds with relatively low ~s will, however, exhibit some attenuation if the organic
content of the soil/aquifer matrix is high. However, the organic content of the soil/aquifer
matrix at Williams AFB is relatively low.
KNINEW.RODIJ 2.IS.92/F
4-3
-------
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SSO I-W- 15 (SAMPLE BENZENE CONCENTRATION, IN PPB)
(16) ((,,) DENOTES FREE-PHASE PRODUCT IN WELL.]
(D) DEEP MONITORING WELL
(NO) SAMPLE RESULT IS NONDETECT FOR BENZENE
flQ..URE 4-2
WILLIAMS AIR FORCE BASE
LIQUID FUELS STORAGE AREA
5 ppb BENZENE ISOCONCENTRATION
LINE AS OF OCTOBER 1991
SCALE:
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-----_.__.J
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APPROXIMATE MAXIMUM EXTENT OF
FREE -PIIASE PRODUC:r PLUME
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INTERNATIONAL
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CORPORATION
-------
For several groups of compounds, including phenols, phthalate, and monocyclic aromatics
(benzene, toluene, and xylene), volatilization, sorption, and biodegradation are all prominent
processes. Generally, in surface waters volatilization dominates, whereas in the subsurface
environment, biodegradation or sorption will dominate depending on the amount of natural
humic material in the receiving soils and the availability of oxygen.
For information concerning persistence in the environment for specific chemicals, see Section
5.2 in the OU-2 RI Report.
4.3.2 Contaminant Migration
Contaminant transport modeling of the dissolved-phase contaminants was carried out using
the two-dimensional, finite difference solute transport (Methods of Characteristics, MOC)
computer model developed by Konikow and Bredehoeft (1978). This modeling was carried
out to establish the transport characteristics of the uppermost aquifer and to provide an
estimate of contaminant concentrations and gradients for the BTEX compounds in support of
a baseline risk assessment.
The plume area predicted by the model was in agreement with the historical distribution of
benzene over much of the site; however, the distribution of toluene, ethyl benzene, and
xylene was overestimated in most cases, especially at the plume edges.
This modeling investigation predicted that concentrations of BTEX compounds in
groundwater resulting after 70 years of contamination from a continuous, nondiminishing
source would be approximately 20 ppm for benzene and toluene, and between 1 and 4 ppm
for ethyl benzene and xylene. The plume periphery for each of these compounds would have
migrated far beyond the boundary of OU-2. These results showed that groundwater in the
area would be significantly affected over the long term if no remediation is initiated.
For information or modeling specifics concerning contaminant migration, see Section 5.3 in
the OU-2 RI Report.
KN/NEW.ROD/12-1S-92IF
4-4
-------
5.0 Summary of Potential Site Risks
5. 1 Chemicals of Potential Concern
The baseline risk assessment identified the chemicals of potential concern at OU-2. This
identification process included summarizing the analytical data for OU-2 and evaluating the
data according to U.S. EPA guidelines for CERCLA risk assessments (U.S. EPA, 1989).
Chemicals of potential concern were selected from the list of all detected constituents based
on the following:
. Frequency of detection - if chemicals were detected at greater than 5 percent
frequency.
. Comparison to method blanks - if sample concentrations exceeded laboratory
blank concentrations by 10 times for common laboratory contaminants and 5
times for all other analytes
. Comparison to background - if the range of concentrations from OU-2 samples
exceeded the range of background values.
This evaluation and selection process is discussed in greater d~tail in the OU-2 R: Report.
Section 6.2. All organic chemicals and metals selected as chemicals of potential concern
were carried forward through the risk assessment calculations.
5. 1. 1 Groundwater
Of the 36 organic chemicals and metals detected in the groundwater, 21 were identified as
chemicals of potential concern and are presented in Table 5-1. The list includes nine
potentially fuel-related organics (benzene, ethyl benzene, 2-methylnaphthalene, 2-
methylphenol, 4-methylphenol, naphthalene, phenol, toluene, and xylene), five non-fuel
related organics (bis[2-ethylhexyl]phthalate, 1,2-dichloroethane, methylene chloride,
tetrachloroethene, and trichlorofluoromethane) and seven metals (antimony, chromium,
copper, lead, nickel, silver, and zinc). These metals are unlikely to be site-related; however, .
due to the difficulty in obtainin::, representative background concentrations for comparison,
they were carried into the risk assessment.
5.1.2 Soil
Of the 28 organic chemicals and metals detected in subsurface soil at OU-2, including soils
below 25 feet, 19 were identified as chemicals of potential concern and are presented in
Table 5-2. The list includes twelve potentially fuel-related organics (benzene,
KN/NEW.ROD/J2-JS-92/F
5-1
-------
Table 5-1. Chemicals of Potential Concern in Groundwater
Range of Detected Concentrations
Chemical of Potential Concern (mg/L)
Organics
Benzene 0.0006 - 24.0
Bis (2-ethyl hexyl) phthalate 0.002 - 0.028
1,2-Dichloroethane 0.0008 - 0.016
Ethyl Benzene 0.0005 - 3.5
Methylene Chloride 0.260 - 0.282
2-Methylnaphthalene 0.006 - 10.0
2-Methylphenol 0.002 - 0.14
4-Methylphenol 0.006 - 0.073
Naphthalene 0.004 - 7.2
Phenol 0.011 - 0.18
Tetrachloroethene 0.005 - 0.0012
Toluene 0.048 - 24.0
T ric h 10 rofl uoro metha ne 0.0007 - 0.0022
Xylenes (total) 0.0006 - 9.8
Metals
Antimony 0.012 - 0.433
Chromium 0.0042 - 54.5
Copper 0.0085 - 0.5
Lead 0.0011 - 0.079
Nickel 0.010 - 4.99
Silver 0.0029 - 0.111
Zinc 0.0059 - 3.969
KN/NEW.5A/12.11.92/F
-------
Table 5-2. Chemicals of Potential Concern in Subsurface. Soil
Range of Detected Range of
Chemical of Potential Concentrations Background b
Concern (mg/kg) (mg/kg).
Organics
Acetone 0.003 - 0.91
Benzene 2.0 - 730.0
Bi s (2 -ethy Ihexyl) phthalate 3.1 - 16.0
Chlorobenzene 27.0 - 300.0
1,2-Dichlorobenzene 2.0 - 140.0
1,3-Dichlorobenzene 2.0 - 130.0
1 A-Dichlorobenzene 2.0 - 180.0
Ethylbenzene 1.0 - 410.0
2-Hexanone Note c
Methylene Chloride 0.017 - 0.47
2 -Methylnaphthalene Note c
4-Methyl-2-pentanone Note c
Naphthalene Note c
Phenol Note c
Toluene 2.0 - 1,200.0
Xylenes (total) 4.0 - 1,500.0
Metals
Antimony 20.0 - 48.0 1.0
Cadmium Note c NA
Lead 4.6 - 1,100.0 15.0 - 150.0
NA = Background data are not available for these metals.
Soil 1 foot or more below the surface is considered subsurface.
Background concentrations for the Phoenix area taken from. Element Concentrations in Soils and
Other Surficial Materials of the Conterminous United States,. USGS Geological Survey Professional
Paper 1270, 1984.
These chemicals of potential concern were detected in the soils below 25 feet and will be addressed in
OU-3.
KN/NEW.5B/12-11-92/F
-------
chlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene,
ethylbenzene, 2-methylnaphthalene, 4-methyl-2-pentanone, naphthalene, phenol, toluene, and
xylene), four non fuel-related organics (acetone, bis[2-ethylhexyl) phthalate, 2-hexanone, and
methylene chloride), and three metals (cadmium, antimony, and lead). Of the above, 2-
Hexanone, 2-methylnaphthalene, 4-methyl-2-pentanone, naphthalene, phenol, and cadmium
were detected at depths below 25 feet and will be addressed as part of the OU-3 remedial
investigation, not as part of this OU-2 ROD.
Of the 29 organic chemicals and metals detected in the surface soil (first foot of soils)
samples, 6 were identified as chemicals of potential concern and are presented in Table 5-3.
These six organic chemicals and metals (acetone, beryllium, bis[2-ethylhexyl) phthalate,
cadmium, diethylphthalate, and di-n-butylphthalate) are not fuel-related and are probably not
site-related, as supported below.
Acetone and the phthalate compounds are common sampling and analytical contaminants and
are ubiquitous in environmental sampling efforts. To be health protective, they are included
in the risk assessment because blank contamination for these chemicals could not be
conclusively documented. Section 5.4 documents that they do not represent risk at levels of
concern .
Beryllium and cadmium were the only two metals not eliminated from the list of chemicals
of potential concern based on background concentrations. Cadmium could not be excluded
from the list of chemicals of potential concern because no background concentration data was
available for this metal; however, cadmium in surface soils does not present a significant
risk, as discussed in Section 5.4. The beryllium background concentrations from the Phoenix
area range from 1.0 to 1.5 ppm. The range of detected beryllium concentrations (2.3 to 3.5
ppm) was only slightly above this background concentration range. It is also documented
that beryllium is released to the atmosphere during the combustion of fossil fuels, such as
flight operations at the Base, and it subsequently deposits on the ground surface. Therefore,
background levels of beryllium in surface soils could be elevated due to the nearby
combustion of fossil fuels (U.S. EPA, 1984). There are uncertainties to consider with the
comparison to background data (i.e., sufficient background data were not available for a
statistical comparison to be made) and the available background data are regional published
data rather than site-specific data. These considerations were included in the evaluation of
the potential risks associated with exposure to surface soil along with the fact that the
measured beryllium levels were nearly equivalent to background.
KNINEW.ROD/J2-J5-92/F
5-2
-------
Table 5-3. Chemicals of Potential Concern in Surface II Soil
Range of Detected Range of
Concentrations Background b
Chemical of Potential Concern (ppm) (ppm)
Organics
Acetone 0.002 - 0.033
Bis (2 -ethylhexyl) phthalate 0.037 - 0.960
Diethylphthalate 0.026 - 0.165
Di-n-butylphthalate 0.025 - 0.165
Metals
Beryllium 2.2 - 3.5 1.0-1.5
Cadmium 1.4 - 2.8 NA
Soil from surface to 1 foot is considered surface.
Background concentrations of metals for the Phoenix area taken from" Element
Concentrations in Soils and Other Surficial Materials of the Conterminous United States,"
USGS Geological Survey Professional Paper 1270, 1984.
KNINEW.5CI12-15-92IF
-------
5.2 Exposure Assessment
Under the current land-use scenario, the potential exposure pathways evaluated include
incidental ingestion of soil, dermal contact with soil, and inhalation of fugitive dust. The
receptor evaluated for these pathways was an on-site Base worker. Because there are
currently no production wells in the contaminated area, no pathways were evaluated for
groundwater under the current land-use scenario.
The potential exposure pathways evaluated under the future land-use scenario include
ingestion of groundwater, inhalation of chemicals volatilized from groundwater during
household water use, incidental ingestion of soil, and dermal contact with soil. Because
residential development is possible in the future, a residential receptor was evaluated for
these pathways.
5.2. 1 Groundwater
The chemicals detected in the groundwater at OU-2 have not been detected in any on- or off-
Base production wells. This groundwater does not discharge to the surface anywhere in the
area; therefore, there is currently no contact point for human or environmental exposure to
these chemicals in groundwater.
Potential future migration of the chemicals present in the groundwater at OU-2 has been
modeled. The results of this modeling indicate that the site-related chemicals are not
expected to affect any existing Base production wells since these wells (BP-05, BP-06, and
BP-08) are located upgradient (west) of the contaminant plume. The shallow aquifer that
exists at OU-2 does not appear to exist in the eastern portion of the Base where Base
production well BP-07 is located. Any constituents that reach the eastern-most extent of the
shallow aquifer or any contaminants currently in the deep aquifer would be expected to travel
north in the deep aquifer from this point rather than continuing east. If, under a future land
use scenario, a production well were to be developed inside the plume, the risks to
residential receptors have been evaluated and are presented in the baseline risk assessment.
The parameters used for this evaluation are an adult exposure of 30 years, a body weight of
70 kg, and an ingestion rate of 1.4 L/day. Exposure point concentrations can be found in the
OU-2 RI Report, Table 6-10.
KNINEW.RODI12-IS-921F
5-3
-------
5.2.2 Surface Soil
Access to chemicals in soil at OU-2 is currently limited by fencing. Therefore, juvenile and
adult residents and visitors to the Base are prevented from contacting the soil. Because this
is a fenced area on an active military base, the potential for a trespasser to contact this area
is extremely low, and the potential for repeated contact is negligible. Fo::' these reasons, the
trespasser scenario was not evaluated in the risk assessment. It is possible that workers in
these areas may contact the soil and may be exposed to site-related chemicals via ingestion
and dermal contact. In the future, after the Base is closed, it could be possible for both
children and residents to come into contact with the soil. This could result in exposure via
ingestion and dermal contact with soil. The parameters used for the evaluation of residential
exposure include a 30-year exposure period divided between a 6-year juvenile exposure and a
24-year adult exposure. Body weights used were 16 kg for a juvenile and 70 kg for an adult.
Ingestion rates used were 200 mg/day for juveniles and 100 mg/day for adults.
Future residential development could result in exposure via uptake of chemicals from the
surface soil into homegrown vegetables. Because this pathway has a much greater level of
uncertainty than direct ingestion, it was addressed qualitatively in the risk assessment. Given
the negligible risks estimated for incidental ingestion and dermal adsorption, the addition of
this pathway was not expected to result in an unacceptable risk. To substantiate this
position, Table 5-4 presents the estimated exposure to chemicals in surface soils through a
vegetable ingestion pathway. (Acetone is not shown in the table because it was assumed that
it would volatilize before it could be taken up by vegetables.) The table shows that the
potential for adverse impacts due to ingestion of homegrown vegetables is negligible.
Base personnel who work at ST -12 may also be currently exposed to volatile organic
compounds (VOCs) and fugitive dust. The only volatile compound detected in surface soil
was acetone in sampl~s at concentrations of 2 to 33 ppb. Therefore, inhalation of volatiles
was not considered to be a significant potential pathway for exposure at OU-2. Nonvolatile
chemicals may become airborne via fugitive dust. This pathway was evaluated for these
chemicals. Other potential receptors (residents, visitors, and other Base personnel) may also
be exposed to airborne chemicals; however, airborne concentrations will decrease rapidly
outside the site boundary, and these receptors will tend to be transient (i.e., they will not
remain at the fence line for prolonged periods). Because evaluation of the dispersion of
fugitive dust on site resulted in negligible potential airborne chemical concentrations, off-site
residential exposure was not quantified for this pathway.
KN/NEW.ROD/12-1S-92/F
5-4
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Table 5-4. Estimated Risk Due to Exposure via Vegetable Ingestion Pathway
Estimated Risk Due
Plant Exposure Relative to Exposure via
Uptake to Incidential Vegetable Ingestion
Chemical 8 Factor b Ingestion Pathway C Pathway d
ILCR HI
Beryllium 0.0015 0.10 1. 2 x 1 0-6
Bis(2 -ethylhexyl) phthalate 0.033 2.1 4.2 x 10.9
Cadmium 0.15 9.5 1.0x10"
Diethyl phthalate 1.4 92 1.2 x 10-6
Di-n-butyl phthalate 0.022 1.4 1.4 x 10-6
8 Chemicals of potential concern in site surface soils. VOCs were not included because they are
expected to volatilize from surface soils over time.
b Uptake factors for inorganics (for reproductive portion of plant only) from Baes, et aI., 1984 and
NCRP No.3, 1989. Uptake factors for organics (for entire plant) from Travis and Arms, 1988.
Plant uptake factors are on a dry weight basis. A ~et-dry conversion factor was applied
assuming 87.5 percent moisture for vegetables (Baes, et at., 1984).
C Calculated as proportion of intake relative to child incidential soil ingestion pathway.
d Calculated by multiplying the exposure relative to incidential soil ingestion pathway by the
incidential soil ingestion pathway ILCR or HI for each chemical (see Tables 5-5 through 5-8).
KN/NEW.5D/12-11.92/F
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A screening approach was taken to verify the assumption that inhalation is not a significant
pathway for chemicals detected in surface soil at OU-2. The potential airborne concentration
of vapor-phase acetone was evaluated for an on-site worker and a resident at the nearest on-
base housing (approximately 150 meters southwest of OU-2). Acetone was used because it
was the only volatile compound detected in the surface soil at OU-2. The potential airborne
concentration of beryllium as fugitive dust was evaluated for an on-site worker and a resident
of on-Base housing. Beryllium was used because it was found at the highest concentration of
any carcinogen in the surface soil at OU-2. The evaluation showed that this pathway is a
negligible contributor to the total potential exposure at OU-2.
5.2.3 Subsurface Soil
There is currently no potential for contact of subsurface soils to receptors. VOCs may
volatilize into pore spaces and migrate upward toward the surface. Due to the depth of the
contamination and the distance to the nearest residential area, this is not considered a
significant potential exposure pathway. The potential airborne concentration of benzene was
evaluated for an on-site worker and a resident at the nearest on-Base housing (approximately
150 meters southwest of OU-2) to verify this assumption. Benzene was used because it was
found at the highest concentration of any volatile carcinogen at OU-2. The evaluation
showed that this pathway is an insignificant contributor to the total potential exposure.
Chemicals present in subsurface soils may become available to receptors in the future as a
result of leaching to groundwater (assuming a production well is installed in the area) or deep
excavation of the area. Because pan evaporation in Phoenix exceeds precipitation, no net
infiltration of rainfall into the soil is expected to occur. Without infiltration, leachate cannot
form and any petroleum hydrocarbon residue adhering to the soil will tend to remain in
place. The petroleum hydrocarbons that have reached the groundwater appear to have
originated from subsurface leaks in petroleum pipelines or tanks and flowed downward from
that point to the water table. These pipelines and tanks have been removed, so no additional
petroleum hydrocarbons are expected to reach groundwater from this source (Le., the
pipeline leaks). Possible leaching of the hydrocarbons in the ST-12 soils below 25 feet into
the groundwater may occur and will be addressed in OU-3.
Future land use after Base closure could include irrigating agriculture, but infiltration to the
water table would not occur unless the annual irrigation rate exceeds 72 inches (NOAA,
1968, 1983). If there was infiltration of water through the soil to the water table, the
KNINEW.RODI12-15-92/F
5-5
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residual hydrocarbon in the soils would be dissolved by the infiltrating water and could leach
to the water table.
Direct contact is not expected for soils deeper than 10 feet under a future residential
development scenario (Reynolds et al., 1990). Based on data gathered from the site, the
majority of the contamination at the site is below lO feet deep.
5.3 Contaminant Toxicity Information
This section provides information regarding the type and severity of adverse health effects
associated with exposure to the chemicals of potential concern in groundwater and soil and a
measure of the dose/response relationship for each. These dose/response relationships are
provided in the form of U.S. EPA-approved reference doses (RID) and cancer potency
factors (CPF). This information is summarized in Tables 5-5 through 5-8. RID in this
context refers to the chronic reference dose, which is an estimate of a daily exposure level
for the human population, including sensitive subpopulations, that is likely to be without an
appreciable risk of deleterious effects for long-term exposures to a compound. The CPF (or
slope factor) is an estimate of the probability of a response (cancer) per unit intake of a
potential carcinogen over a lifetime. The CPF is used to estimate an upper-bound probability
of an individual developing cancer from a lifetime exposure to a particular dose of a potential
carcinogen (U.S. EPA, 1989a). Further detailed information concerning the toxicity of
individual chemicals is presented in Section 6.4 of the OU-2 RI Report.
Uncertainties associated with the RIDs for each chemical are addressed by U.S. EPA by
modifying the results of animal and human studies by factors of 10, 100, or 1,000. An
uncertainty factor of 10 is used when the RID is based on chronic human studies. An
uncertainty factor of.lOO is used to account for the extrapolation of animals to humans when
the RID is based on experimental animal data. An uncertainty factor of 1,000 is used when
the RID is based on an animals' lowest observed effect level (LOEL) instead of a no
observed effect level (NOEL). These uncertainty factors are designed to overestimate, rather"
than underestimate threshold limits for humans.
There are also several sources of uncertainty inherent in cancer slope factors. The weight-
of-evidence classification is a qualitative estimate of the likelihood that a chemical will induce
cancer in humans. These range from Group A (human carcinogen - sufficient evidence of
carcinogenicity in humans) to Group E (evidence of noncarcinogenicity in adequate studies).
Other uncertainties, as with RIDs, arise from high to low dose extrapolations, animal to
KN/NEW.ROD/12-IS-92/F
5-6
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Table 5-5. Summary of Potential Incremental Lifetime Cancer Risks (llCR)
Associated With OU-2 at Williams AFB: Current land Use
Estimated Cancer CPF
Average Potency. Adjusted for Weight Chemical Total Total
Constituent Daily Intake Factor (CPF) Absorbed of Type of Specific Pathway Exposure
(mg/kg-day) (mg/kg-day)" Dose Evidence Cancer ILCR ILCR ILCR
Exposure Pathway: Occup
-------
Table 5-6. Summary of Potential Incremental Lifetime Cancer Risks (lLCR)
Associated With OU-2 at Williams AFB: Future Land Use
(Page 1 01 2)
Estimated CPF
Average Daily Cancer Potency. Adjusted Chemical Total Total
Intake Factor (CPFI lor Weight 01 Type of Specific Pathway Exposure
Constituent (mg/kg-dayl (mg/kg-day), Absorbed Evidence Cancer ILCR ILCR ILCR
Dose d
Exposure Pathway: Ingestion 01 Groundwater From a New On-Base Well
Benzene 2.6xlO.3 2.9 x 10.2 NO A Leukemia 6.2xlO.5
B is (2 -ethylhexyl )phtha late 1.4x105 1.4 x 10.2 NO 82 Liver 8.3 x 10.9
1,2-Dichloroethane 3.0x100 9.1x102 NO B2 Circulatory 2.7xlO.1
Methylene chloride 1.9 x 10.5 7.5xlO.3 NO 82 Liver 1.4 x 10.1
T etrachloroethene 1.2 x 100 5.1x10.2 NO 82 Liver 6.1 x 10.9
6.2 X 105
Exposure Pathway: Inhalation of VOCs DuiinQ ShowerinQ with Groundwater From a New On-Base Well
Benzene 1.6 x 10.4 2.9x 10.-2 NO A Leukemia 4.6xlO'0
Bis (2 -ethylhexyllphthalate 2.0 x 10.11 1.4 x 10 .2b NO B2 Liver 2.8 x 10 .13
1,2-Dichloroethane 4.1 x 10.1 9.1 X 10.2 NO B2 Circulatory 3.7 x 10.9
Methylene chloride 5.2 x 10.1 1. 7 x 10.3 c NO B2 Lung; Liver 2.4 x 10 .'3
T etrachloroethene 7. 1 x 10.0 1.8 x 10.3 NO B2 Liver; 1.3 x 10.9
Leukemia
4.7 x 10.0
Future Residential EXDosure: Total Groundwater ILCR 7 x 10.5
: '. .'. '. '. . ..." ',' .'. .'.. .
EXDosure Pathway: Inaestion 01 Contaminated Soii by Adults and Children
Bis (2 -ethylhexyllphthalate 1.5 x 10.1 0.014 NO B2 Liver 2.0 x 10.9
Beryllium 2.8 x 10.0 4.3 NO B2 NA 1.2 x 10.5
1.2 x 10.5
KN/NEW.5F/12-11-92/F
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Table 5-6
(Page 2 01 21
Estimated CPF
Average Daily Cancer Potency. Adjusted Chemical Total Total
Intake Factor (CPF) for Weight 01 Type 01 Specific 1',;lliwiJY Exposure
Constituent (mg/kg-day) (mg/kg-day), Absorbed Evidence Cancer ILCR ILCR ILCR
Dose d
Exposure Pathway: Dermal Contact with Soil by Adults and Children
Bis(2 -ethylhexyllphthalate 1.0 x 10 1 0.014 YES NA NA 1.5 x 109
1.5x10tl
Future Residential Exoosure: Total Soil ILCR 1 x 105
Future Residential Exposure: Total Potential ILCR (weight 01 evidence predominantly A) 8 x 105
NA - Not Applicable
. From U.S. EPA, 1990b
b Ingestion value used. no inhalation value available.
C Calculated from a unit risk of 4.7xlO.1IJ1g/m3)" as: (4.7x10.1mlpgl (70kgl/(20m3/day)(10 .3mg/pg).
d (Oral CPFII(oral absorption efficiency) = Absorbed CPF. Oral absorption efficiencies were taken from Jones and Owen (19891.
available. an absorption efficiency of 100% was assumed for organic compounds.
If no absorption efficiency was
KN/NEW.5F/12.11-92/F
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Table 5-7. Summary of Potential Hazard Indices (HI)
Associated with OU-2 at Williams AFB: Current Land Use
Estimated
Average Daily Reference RfD Adjusted Chemical Total Total
Intake Dose' (RfDl for Absorbed Uncertainty Specific Pathway Exposure
Constituent (mg/kg-dayl (mg/kg-dayl Dose Critical Effect Factor HI HI HI
Exposure Pathway: Occupational Ingestion of Contaminated Soil
IAcetone 2.8 x 10.8 0.1 NO Liver. kidney 1000 2.8 x 10.8
Bis( 2 -ethylhexyll phthalate 1.8 x 10.7 0.02 NO Liver; kidney 1000 8.8 x 10.6
Di-n-butylphthalate 4.8 x 10.8 0.1 NO Mortality 1000 4.8 x 10.7
Diethylphthalate 4.8 x 10.8 0.8 NO Red1Hirs body 1000 6.1 x 10.8
welg
Beryllium 3.4 x 10.6 0.005 NO 100 6.8 x 10.4
Cadmium 2.7 x 10.6 0.0005 NO Kidney 10 5.4x10.3
6.1 x 10.3
Exposure Pathway: Occupational Dermal Contact with Soil
IAcetone 1 .5 x 10.9 0.1 b YES NA 1000 1.5 x 10.8
Bis(2-ethyl hexyllphthalate 9.6 x 10.8 0.02b YES NA 1000 4.8 x 1 0 .6
Di-n-butylphthalate 2.6 x 10.6 0.85b YES NA 1000 3.1 x 10 -6
Diethylphthalate 2.6 x 10.8 0.8b YES NA 1000 3.3 x 10.8
5. 1 x 10.6
Exposure Pathway: Occupational Inhalation of Fugitive Dust
t1.cetone 1. 3 X 1 0 .22 0.1 b NO 1000 1.3 x 10 .21
Bis (2 -ethylhexyll phthalate 8.6 X 10 .16 0.02b NO 1000 4.3 x 10 -13
Di-n-butylphthalate 2.4x10'16 0.1 NO 1000 4.7xlO'13
Diethylphthalate 2.4 x 10 .16 0.8 NO 1000 3.0 x 10 .16
Beryllium 1.7xlO.'3 0.005 b NO 100 3.3 x 10.11
Cadmium 1.3 x 10 .13 0.0005 b NO Kidney 10 2.7 x 10 .10
3.0 x 10 .10
6 x 10.3
. From U.S. EPA, 1990b
b Oral RFDs adjusted for absorbed dose 8S per U.S. EPA (1989al: (Oral RFDlloral absorption efficiency I = Absorbtion FRD. Oral absorption efficiencies were
taken from Jones and Owen (19891. If no absorption efficiency was available. an absorption efficiency of 100% was assumed for organic compounds.
ICIII'IIIFW o;~/' ?".!l2/F
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Table 5-8. Summary of Potential Hazard Indices (HIS)
Associated With OU-2 at Williams AFB: Future land Use
(Page 1 of 3)
Estimated Average Reference RfD Adjusted Chemical Total Total
Daily Intake Dose' (RfDl for Absorbed Uncertainty Specific Pathway Exposure
Constituent (mg/kg-dayl (mg/kg-dayl Dose Critical Effect Factor HI HI HI
Exposure Pathway: Ingestion of Groundwater From a New On-Base Well
Bis (2 -ethylhexyl) 8.9 x 10.6 0.02 NO Liver 1000 4.4xlO'3
phthalate
Ethylbenzene 6.7 x 10.3 0.1 NO Liver, kidney 1000 6.7 x 10.2
Methylene chloride 2.8 x 10.4 0.06 NO Liver 100 4.7 x 10.3
Naphthalene 7.0xlO.3 0.004 NO Body weight 10000 1.8x10o
Phenol 3.8 x 10.4 0.6 NO Fetal body wt. 100 6.4 x 10.4
Tetrachloroethene 1. 8 x 10.6 0.01 NO Hepatotoxicity 1000 1 .8 X 10.3
Toluene 3.1 x 10.2 0.2 NO Liver, kidney 1000 1.6 x 10"
T richlofluoromethane 3.3 x 1 0 .6 0.3 NO Mortality 1000 1 .1 x 1 0.4
Xylenes 7.9 x 1 0.3 2.0 NO Hyperactivity, body 100 4.0 x 10.3
weight, increased
mortality
Antimony 7.1 x 10'4 0.0004 NO Blood, lifespan 1000 1.8 x 10 °
Chromium 3.9 x 10.2 0.005 NO Not defined; liver 500 7.8xlO0
Copper 8.5 x 10.4 0.037 b NO GI tract 2.3xlO'2
Lead 1.3 x 10.4 0.0007 NO CNS 1.9 x 10'1
Nickel 4.0 x 10'3 0.02 NO Body and organ wt. 300 2.0 x 10"
Silver 1.4 x 10 ,4 0.003 NO Argyria 2 4.7 x 10'2
Zinc 3.7 x 10'3 0.2 NO Anemia 10 1.8 x 10.2
1.2x10'
.-.-
KNINI'''' 5H/12.11.92/F
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Table 5-8
(Page 2 of 31
Estimated Average Reference RfD Adjusted Chemical Total Total
Daily Intake Dose' (RfDl for Absorbed. Uncertainty Specific Pathway Exposure
Constituent (mg/kg-dayl (mg/kg-dayl Dose Critical Effect Factor HI HI HI
Exposure Patt{iNay: Inhalation of VOCs During Showering Vvlth Groundwater From a New On-Base Well
Bis(2-ethylhexyll 3.0 x 10 -\0 0.02 < NO 1000 1 .5 x 10.8
phthalate
Ethylbenzene 7.2 x 10.4 0.29d NO 1000 7. 1 x 10.3
Methylene chloride 7.6 x 1 0.8 0.86° NO 100 8.9 x 10.8
Naphthalene 4.5 x 10.6 0.004 < NO 10000 1 .1 x 1 0 .2
Phenol 3.6 x 10.9 0.6< NO 100 6.0 X 10.9
Exposure Pathway: Inhalation of VOCs During Showering With Groundwater From a New On-Base Well ..
IT etrachloroethene 1 .0 x 10.4 0.01 < NO 1000 1.0 x 10.2
oluene 2.5 x 10.3 0.57' NO CNS, eyes, nose 100 4.4 x 10.3
... richlorofluoromethane 5.2 x 10.8 0.2 NO Elevated blood urea 10,000 2.6 x 10.6
nitrogen, lung
lesions
Xylenes 1.8 x 10'3 0.086 NO CNS, nose, throat 100 2.1 x 10.2
5.5 x 10'2
Future Residential Exposure: Total Groundwater HI 1.2x10\
. .. '. . . .
.. ." .
Exposure Pathway: lrigestjo~ of Contaminated Soi.l by Chiidreriarid Adults
Acetone 5.7 x 10.8 0.1 NO Liver, kidney 1000 5.7 x 10.8
Bis(2- 3.6 x 10.7 0.02 NO Liver 1000 1. 8 x 10.6
lethylhexyllphthalate
Di-n-butylphthalate 1 .0 x 10.1 0.1 NO Mortality 1000 1.0 x 10.8
KN/NEW.6HI1 2.11.9 2/F
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Table 5-8
(Page 3 of 3)
Estimated Average Reference RfD Adjusted Chemical Total Total
Daily Intake Dose. IRfD) for Absorbed Uncertainty Specific Pathway Exposure
Constituent Img/kg-day) Img/kg-day) Dose Critical Effect Factor HI HI HI
Diethylphthalate 1.0 x 10.7 0.8 NO Reduced body 1000 1.3 x 10.7
weight
Beryllium 7. 1 x 10.8 0.005 NO 100 1 .4 x 10.3
Cadmium 5.7 x 10.8 0.0005 NO Kidney 10 1 . 1 x 1 0.2
1.2 x 10.2
Exposure Pathway: Dermal Contact with Soil by Children and Adults
Acetone 4. 1 x 10.9 0.19 YES NA NA 4.1 x 10.9
8;sI2- 2.6 x 10.7 0.029 YES NA NA 1.3 x 10.6
ethylhexyllphthalate
Di-n-butylphthalate 7.2 x 10.8 0.859 YES NA NA 7.2 x 10.7
Diethylphthalate 7.2 x 10.8 0.89 YES NA NA 9.1 x 10.8
1.4 x 10.6
Future Residential Exposure: Total Soil HI 1.2xlO.2
Future Residential Population: Total Potential HI 1 x 101
.From U.S. EPA, 19900
bFrom MCL (1.3mg/LI
"Ingestion valua, no inhalation value available
dCalculeted from RFC of 1.0mg/m" as: /1.0mg/m"H20m"/day)/70kg
.Celculated from RFC of 3.0mg/m" as; (3.0 mg/m"1I20m"/doyl/70kg.
'Calculated from FRC of 2.0mg/m" as: (2.0mg/m"H20m"/daylnOkg.
.Orol RFDs adjusted for absorbed dose as per U.S. EPA 11989al: (Oral RFDI (oral absorption efficiency) = Absorbed RFD oral absorption efficiencies were token from Jones and Owen 11989).
If 00 absorption officiency was available, an absorption efficiency of 100% was assumed for orgenic compounds.
KNi'
'HII2.11.92/F
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human extrapolations, and intraspecies variation in experimental animals or human
populations.
5.4 Risk Characterization
This section addresses the potential for adverse health effects (both cancer and other toxic
effects) based on a quantitative characterization of risk. The risk characterization takes into
account the magnitude of exposure to a chemical of potential concern (dose), as discussed in
Section 5.2, and the chemicals' toxicity (Section 5.3). Risks are characterized for carcinogenic
chemicals in terms of incremental lifetime cancer risk (ILCR), and for noncarcinogenic
chemicals with. other toxic effects in terms of a hazard index (HI). Both of these are discussed
below.
5.4.1 Carcinogenic Effects
ILCRs were estimated for each carcinogenic chemical of potential concern and are expressed in
terms of additional cancers that might be anticipated as a result of specific exposure to an
external influence. Thus, a 1 x 10-6 ILCR indicates that one additional person in one million is
likely to develop some form of cancer. Estimation of ILCR is given by:
ILCR = (CPF)(CDI)
where:
ILCR
CPF
CDI
= Incremental lifetime cancer risk (unitless)
= Carcinogenic potency factor [(mg/kg/day)-I]
= Chronic daily intake (mg/kg/day), equivalent to average daily intake.
The CPFs used are the most recent values developed by the Carcinogen Assessment Group
(CAG) of U.S. EPA as cited in their Integrated Risk Information System (IRIS) data base
(U.S. EPA, 1991a) and Health Effects Assessment Summary Tables (U.S. EPA, 1990c).
The U.S. EPA recommends the use of an acceptable risk range (de minimis level) of 1 x lQ4
to 1 x lQ-6 for CERCLA sites (U.S. EPA, 1990b). The results of the quantitative risk
characterization for carcinogenic chemicals are shown in Tables 5-5 and 5-6.
For the current land use scenario (Le., continued normal Base operations), the greatest ILCR
associated with chemicals in the surface soil at OU-2 is from beryllium via incidental
ingestion of soil (5.9 x lQ-6). This is within the de minimis level of 1 x 10-4 to 1 x lQ-6 set
by the U.S. EPA in the NCP. In addition, the potential ILCR associated with naturally
occurring beryllium. in surface soils is 2.5 x 10-6 in this area; therefore, the increased risk
KNINEW.ROD/12-1S-92IF
.5-7
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I-
I
associated with beryllium in surface soils at OU-2 is not considered significantly elevated
when compared to background and is considered essentially equivalent to the risk associated
with the background levels. The neXi highest potential ILCR at OU-2 is associated with
bis(2-ethylhexyl)phthalate via incidental soil ingestion (1 :.: 1O-~. ?or the c"-":Tent land use
scenario, there are no potential exposure pathways from subsurface soils or groundwater, as
stated earlier in this section.
If OU-2 becomes a residential area after Williams AFB is closed, the greatest potential ILCR
associated with residential exposure to the soil (surface and subsurface were evaluated
together as soil) is a result of beryllium via incidental ingestion of soil (1.2 x 10.5). Again,
the ILCR estimated for beryllium is not significantly greater than that associated with
naturally occurring background concentrations of this metal (background ILCR = 5.2 x 1
-------
The HI does not define intake response relationships and its numerical value should not be
construed to be a direct estimate of risk. It is a numerical nearness to acceptable limits of
exposure or the degree to which acceptable exposure levels are .exceeded. As this index
approaches unity, concern for the potential hazard of the constituent increases. Exceeding
unity does not in itself imply a potential hazard; however, it does suggest that a given
situation be more closely evaluated. The results of the quantitative risk characterization for
health risks other than cancer are shown in Tables 5-7 and 5-8.
For the current land use scenario (i.e., continued normal Base operations), the highest
potential HI is associated with cadmium via incidental soil ingestion (5 x 10-3). The total soil
HI associated with current land use is 6 x 10-3. Because this value does not exceed one, the
risk to human health due to non-carcinogens in surface soil is not significant under a current
land use scenario. For the current land use scenario, there are no potential exposure
pathways from subsurface soils or groundwater, as stated earlier in this section.
If OU-2 becomes a residential area when Williams AFB is closed, the highest HI for soil is
cadmium via incidental ingestion (1.1 x 10 -2). The total soil HI associated with future land
use is 1.2 x 10-2. Because this value does not exceed one, the risk to human health due to
non-carcinogens in soils is not significant under a future land use scenario.
The potential for future development of production wells in the plume is small even after the
Base is closed. A future residential scenario has been evaluated to provide an upper-bound
estimate of potential risks associated with exposure to this groundwater. The individual HIs
associated with domestic use of groundwater from OU-2 by a residential population are
greater than one for three chemicals: naphthalene (1.8), antimony (1.8), and chromium
(7.8). As mentioned previously, the metals are not likely to be site-related; however,
naphthalene is not naturally occurring. The total groundwater HI associated with future land
use is 12. Because this value exceeds one, the risk to human health due to non-carcinogens
in groundwater is considered significant under a future land use scenario. These potential
risks would only exist if, after the Base is closed, a residential well is completed within the
unremediated plume at OU-2, a resident uses the groundwater at the levels assumed for 30
years, and there are no institutional controls such as deed restrictions.
KNINEW.RODI12-16-921F
5-9
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5.5 Environmental Evaluation
The purpose of the environmental assessment portion of the baseline risk assessment was to
evaluate if site-related contamination would damage an environmental resource that is highly
important or irreplaceable (e.g. endangered species or sensitive habitat). Environmental
assessment objectives at OU-2 can be met by a qualitative evaluation of the potential for
exposure of critical receptors; however, a comprehensive environmental risk assessment will
be performed at Williams AFB as part of future operable unit investigation and presented in
the comprehensive Base-wide RI results.
OU-2 and the area around it is already highly disturbed due to normal Base operations.
After Base closure this area will likely become residential or possibly agricultural, with the
exception of the remedial action area, which will remain industrial. It is not expected to
revert back to natural habitat. The area around Williams AFB is also highly disturbed by
development and agriculture, therefore, there are no undisturbed areas nearby with which to
compare the species diversity at OU-2. OU-2 also does not provide any significant or unique
habitats because it is developed. None of the endangered species in the Base area were
found to live at or near OU-2, according to observations of Base personnel. This was
expected due to the lack of habitats or prey at OU-2 and confirmed during a site inspection.
It is possible that some endangered or threatened birds of prey may hunt at OU-2; however,
the small size and low number of animals in this area will preclude them from obtaining
more than a small portion of their diet from OU-2. The environmental assessment performed
as part of the future comprehensive environmental risk assessment will address the potential
for environment receptors to be impacted by all of the identified sites at Williams AFB.
After the Base is closed, animals such as reptiles and ground squirrels may be more likely to
frequent OU-2. Exposure to chemicals in soil may occur via ingestion, inhalation of fugitive
dust, or ingestion of vegetation grown in the soil. For nonthreatened or nonendangered
species, individual risk is not generally considered. Risks to the population or community of
environmental receptors are evaluated instead. Due to the low concentrations of
contaminants detected in surface soils at OU-2 and its small area, contact with surface soil is
not considered a significant exposure pathway for population risk. Sensitive species in the
area, such as the peregrine falcon and Swainson's hawk, should not spend a significant
amount of time at OU-2. This observation will be confirmed during the comprehensive
environmental risk assessment previously mentioned.
KNINEW. ROD/12-16-92/F
5-10
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If, in the future, an irrigation well is completed in the contaminant plume, environmental
receptors could be exposed to contaminated groundwater via ingestion of the water, crops
irrigated with this water, or ingestion by carnivores of smaller animals exposed to the water
(e.g., ingestion of water by a ground squirrel followed by ingestion of the squirrel by a
hawk). The primary chemicals present in the groundwater of OU-2 are the fuel-related
organics. These compounds are highly volatile and will probably be lost to volatilization
during irrigation. The other chemicals of potential concern in groundwater at OU-2 have
been detected at a lower frequency and at low concentrations. Eight of these other chemicals
of potential concern appear to be associated with field or laboratory contamination (phthalate
and naphthalene compounds) or are naturally occurring (metals). There are no sensitive
environmental receptors present at OU-2. The endangered species of predatory hawks and
eagles in the area could be exposed to chemicals in groundwater via ingestion of smaller
animals that may inhabit agricultural land (Le., ground squirrels, mice). The contribution of
prey from one area is dependent on the size of the affected area.
KN/NEW.ROD/12-16-92/F
.5-11
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6.0 Description of Alternatives
Under CERCLA, a process has been established to develop, screen, and evaluate appropriate
remedial alternatives. A wide range of cleanup options ha'.',o. jeen considered for the
remediation of OU-2.
The cleanup options that remained following the preliminary screening were assembled into
appropriate remedial alternatives. These alternatives were developed based on site-specific
needs and evaluated using nine criteria developed by the U.S. EPA to address CERCLA
requirements. The evaluation criteria are used to determine the most appropriate alternative.
A list of the nine criteria is provided below.
.
Overall Protection of Human Health and the Environment
Compliance with ARARs
Long-Term Effectiveness and Permanence
Reduction of Toxicity, Mobility, or Volume
Short-Term Effectiveness
Implementability
Cost
S tate Acceptance
Community Acceptance.
.
.
.
.
.
.
.
.
After screening and evaluation of the initial alternatives, the following four remedial alterna-
tives remained under consideration for groundwater and soils at OU-2:
.
Alternative A - No Action
Alternative B - Institutional Action and Capping
Alternative C - Groundwater Extraction, Treatment with Air Stripping, and
Injection plus Soil Vapor Extraction with In Situ Bioremediation
Alternative D - Groundwater Extraction, Air Stripping and Injection plus On-
Site Soil Incineration.
.
.
.
Alternative A represents the baseline as required by CERCLA.
6. 1 Selection of Chemicals Requiring Treatment
To evaluate groundwater, surface soil, and subsurface soil remedial technologies, the
chemicals of potential concern identified during the baseline risk assessment were evaluated
in the FS Report for OU-2 to determine which of them would require treatment to meet the
KN/NEW.ROD/IZ.IS-92/F
6-1
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action levels presented in Appendix A. The methods for this evaluation are presented in the
FS Report for OU-2 and are summarized in Tables 6-1 and 6-2.
6. 1. 1 Groundwater
Data from groundwater monitoring wells as well as modeling used to predict approximate
locations and flows from extraction wells were used to estimate the influent concentration of
each of the chemicals of potential concern at an on site treatment unit. The results of the
evaluation process (performed during the FS process) are summarized in Table 6-1. This
table reports chemicals of potential concern in groundwater and their detection frequency,
maximum detected concentration, action level, and average treatment system concentrations.
The results from the evaluation show that only three chemicals (benzene, naphthalene, and
toluene) in groundwater will require treatment. These chemicals were carried forward
through the FS process as the basis for screening and selecting the groundwater treatment
technologies. TPH measurements were also included in the FS process as a helpful indicator
of overall fuel contamination. No action level has been established for TPH. Rather,
individual action levels were established for the specific components that were detected and
are among the compounds that comprise the class of chemicals reported as TPH. All
evaluations of the groundwater technologies were based on the effectiveness of remediating
the three specific contaminants. This approach is considered conservative because the
treatment alternatives considered are coincidentally effective for treating all of the volatile
compounds detected.
Although only a limited number of chemicals of potential concern were evaluated as needing
treatment, monitoring for all the chemicals of potential concern will continue throughout
remedial design and remedial action. During the remedial investigation, there were
detections of four compounds (antimony, bi~[2-ethylhexyl]phthalate, chromium, and nickel)
in groundwater that are suspected as erroneous detections. The evidence supporting these
conclusions for each of the compounds is presented below, along with continued monitoring
activities.
Antimony was detected in only a few delivery groups of samples sent to the analytical
laboratory. The laboratory did report errors associated with the analyses of antimony in
unrelated samples for other projects during the same period when the delivery groups from
Williams AFB were analyzed; however, the laboratory was unable to identify any problem
with results for antimony samples from Williams AFB. This unresolved issue warrants
additional confirmatory sampling.
KN/NEW. ROD/12-1S-92/F
6-2
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Table 6-1. Chemicals of Potential Concern in Groundwater at OU-2 and Treatment Requirements to Meet Action levels
Average Treatment
DetectionsfTotal Highest Hit Action Level System Concentration
Chemical of Potential Concern Samples (mg/LI (mg/LI (mg/LI Gomment
Benzene 109 142 24 0.005 3.52 Requires treetment to meet ection levels
bis(2-Ethylhexyllphthalate 8 76 0.028 0.006 footnote b Need for treatment contingent on additional sampling
1,2-Dichloroethane 3 77 0.016 0.005 0.002 Does not require treatment to meet action levels
Ethyl benzene 59 142 3.5 0.7 0.537 Does not require treatment to meet action levels
Methylene chloride 3 77 0.282 0.005 0.003 Does not require treatment to meet action levels
2-Methylnaphthalene 10 76 10 NAO 0.62 Does not require treetment to meet ection levels
2-Methylphenol 6 76 0.14 0.87 0.01 Does not require treatment to meet ection levels
4-Methylphenol 4 76 0.073 0.87 0.01 Does not require treetment to meet action levels
Naphthalene 15 77 7.2 0.028 0.47 Requires treatment to meet action levels
Phenol 13 76 0.18 4.2 0.01 Does not require treatment to meet action levels
T etrachloroethene 3 70 0.0012 0.005 0.002 Does not require treetment to meet action levels
Toluene 28 142 24 1.0 4.18 Requires treatment to meet action levels
Trichlorofluoromethene 4 77 0.0022 2.1 0.0002 Does not require treetment to meet action levels
Xylenes 82 142 9.8 10.0 1.23 Does not require treatment to meet action levels
Antimony 5 75 0.433 0.006 footnote b Need for treatment contingent on additional sampling
Chromium" 21 75 54.5 0.1 0.14 Need for treatment contingent on edditional sampling
Copper 14 75 0.5 1.3 0.05 Does not require treatment to meet action levels
Lesd 23 85 0.079 0.015 0.01 Does not require !reatment to meet action levels
Nickel" 20 75 4.99 0.1 0.07 Need for treatmant contingent on additional sampling
Silver 7 75 0.111 0.05 0.01 Does not require traatment to meet ection levels
Zinc 50 75 3.969 1.4 0.12 Doas not require treatment to meet action levels
No U.S.EPA-approved toxicity information is available for daveloping an action levul for this compound.
Action level is below CLP dutuction limit. See discussion in Section 6. ,. 1.
Suu discussion in Suction 6.1 .1.
KN/NEW.6A/12-17.92/F
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Table 6-2. Chemicals qf Potential Concern in Soil at OU-2 and Treatment Requirements to Meet Action levels
Action Surface Soils (top 1 foot) Subsurface Soils {1 foot to 25 feet daepl
Chemical of Potential level
Concarn {mg!kgl Oetectionsl High..t Hit Oetectionsl High..t Hit Avg. Concentretion .
T otel Sompl.. (mg/kgl Comment Tote! Semples (mg/kgl (mg/kgl Comment
Acetone 12.000 7 10 0.033 Highest hit is balow action lavel 4 4 0.91 Not Calculated Highest hit is below action level
Benzene 45 Not a COPC for surface soils 17 69 730 27.1 Requires treatment to maet
action level
bis{2-Ethythexytl 95 9 10 0.96 Highast hit is balow ection level 3 4 16 Not Calculated Highest hit is below ection level
phthalate
Chlorobenzene 2,300 Not a COPC for surface soils 4 69 300 Not Calculated Highest hit Is below action level
Di-n-butytphthelete 12,000 2 10 0_0165 Highest hit is below action level Not a COPC for subsurface soils
1. 2-Dichlorobenzene 10.000 Not a COPC for surface soils 19 69 140 Not Calculated Highast hit is below action level
1,3-Dichlorobenzena 10.000 Not a COPC for surface soils 12 69 130 Not Calculatad Highest hit Is below action level
1.4-Dlchlorobenzane 55 Not a COPC for surface soils 20 69 180 10.6 Requires treatment to meet
action level
Diethvlphthalate 94 000 2 10 0.0165 Highest hit is below action leval Not a COPC for subsurface soils
Ethytbenzene 12.000 Not a COPC for surfaca soils 23 69 410 Not Calculated Highest hit Is below action level
2-Hexanone NA Not a COPC for surface soils Was onlv datactad In soils balow 25 faat and will be eddressed in OU.3
Methvlene chloride 180 Not e COPC for surface solis 4 4 0.47 Not Calculated Highest hit is below action level
2-Methvlnephthalene NA Not a COPC for sur'ace soils Was onlv detected In solis below 25 feet and will be addressed in OU.3
4-Methvl-2'Dentenone 0.95 Not a COPC 'or surfece soils Was only detected In soils below 25 feet end will be addressed In OU-3
Naphthalane 470 Not a COPC for surfaca soils Was only detected in soils below 25 feet and will be addressed In OU-3
Phenol 70.000 Not a COPC for surface soils WaS onh datacted in soils below 25 'eet and will be addressed In OU-3
Toluene 23.000 Not a COPC for surface soils 23 69 1 200 Not Calculated Hiohest hit is below action level
Xvlenes 230.000 Not a COPC 'or surface soils 24 69 1.500 Not Calculated Highest hit is below action level
Antimony 47 Not a COPC for surface solis 4 4 48 Not Calculetad Highest hit is equivalent to
action level
Berytlium 1.0-1.5 10 10 3.5 Higheat hit is equivalant to Not a COPC 'or subsurface solis
background level
Cadmium 58 10 10 2.8 Highest hit Is below action level Was only datectad In solis below 25 faet and will ba addrassed in OU-3
lead 15.150 Not a.COPC for surface soils 93 110 1,100 61.0 Calculated average value Is
within background lavel
NA = No data available for developing en ection level for this compound.
. Average concentretion was celculated for those chemicals of potentiel concarn whose highast hit waa above action levals or background levels beceuse only those chemicals of potentiel concern
exceeding action levels will require treatment.
KN/NEW.68112-' 7-92/F
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Bis(2-ethylhexyl)phthalate was detected i:: early sampling rounds; however, it ceased to be
detected after the use of Teflon TM liners in plastic caps was instituted. Bis(2-ethylhexyl)
phthalate is present in the plastic cap material. It is reasonable to conclude that this chemical
leached into the samples from the unlined caps used in the collection, shipment, and storage
of the samples.
Neither antimony nor bis(2-ethylhexyl)phthalate are added to or naturally occur in jet fuels
and there is no reason to believe that they are site related. In addition, contract laboratory
procedure (CLP) detection limits for these two chemicals exceed the action levels that were
ultimately established for these chemicals (Federal Maximum Contaminant Levels [MCL] to
be enacted in 1994 - see Appendix A, Table A-3). Having a higher detection limit than an
action level results in difficulties with establishing a defensible treatment requirement for the
two chemicals. Even if neither chemical had been detected at the site, there would still be
difficulties in defending a no treatment scenario because the detection limit is still larger than
the action level. To accommodate this dilemma, this ROD selects that treatment for these
two chemicals will be provided contingent on the results of confirmatory sampling conducted
during the remedial design phase using appropriate specialized analyses with lower detection
limits. If the average groundwater t:.~atment system concentrations of these two chemicals
exceed action levels established in Ai: .'~ndix A, USAF will select additional treatment in an
Explanation of Significant Differences. Such treatment will be provided in addition to the
remedy selected in this ROD and will reduce concentrations for either or both of the
chemicals to below the established action levels.
Chromium and nickel detected in several groundwater samples are also likely to be
erroneous. Statistically, the data indicate that elevated chromium and nickel results are
associated with wells installed by IT as opposed to wells installed by A V. For example,
wells SS-01-W-19 and SS-01-W-22, sampled on the same day in December 1990, gave
uncharacteristically elevated levels for chromium and nickel. Wells installed by IT share a
common characteristic of stainless steel well construction materials. The materials of
construction for the well screens and riser casings in those wells are #304 stainless steel.
Chromium and nickel are both alloyed in #304 stainless steel.
Neither chromium nor nickel are added to or naturally occur in jet fuels and there is no
reason to believe that they are site related. The ROD selects that treatment for these two
chemicals will be provided contingent on the results of confirmatory sampling conducted
during the remedial design phase. If the average groundwater treatment system concentration
KN/NEW.ROD/12-17.92IF
6-3
-------
of either of these two chemicals exceed the levels established in Appendix A, then the USAF
will select additional treatment in an Explanation of Significant Differences. Such treatment
will be provided in . addition to the remedy selected in this ROD and will reduce
concentrations for either or both of the chemicals to below the established action levels.
6.1.2 Soil
An evaluation of potential chemicals of concern in surface soils indicates that no remedial
action is required to meet action levels (established in Appendix A) in the top one foot of
soil. For subsurface soil (between one foot in depth to twenty-five feet deep) only two
chemicals (benzene and 1,4-dichlorobenzene) require remediation to meet action levels.
Benzene and 1,4-dichlorobenzene were carried forward through the FS evaluation process as
the basis for screening and selecting the treatment technologies for subsurface soil. TPH
measurements were also included in the FS process as a helpful indicator of overall fuel
contamination. No action level has been established for TPH. Rather, individual action
levels are established for the specific components that were detected and are among the
compounds that comprise the class of chemicals reported as TPH. All evaluations of the
groundwater technologies were based on the effectiveness of remediating the two specific.
contaminants.
6.2 Alternative Description
Alternative A: No Action
The no-action alternative provides no remediation and leaves the free-phase product and
contaminated groundwater unaffected. The no-action alternative for contaminated soils
would not alter site conditions; all areas having concentrations of contaminants exceeding
action levels would remain as is. This alternative includes long-term monitoring of both
groundwater and soils in order to detect changes in the contaminant levels in the designated
areas to determine if there have been reductions below the action levels due to natural
degradation of contaminants. Monitoring would be through soil borings and sampling at
selected groundwater monitoring wells at OU-2. Reassessment of site conditions would be
performed every 5 years in accordance with CERCLA Section 121(c).
. This alternative does not reduce the potential human health risk posed by ingestion of
contaminated groundwater from the upper aquifer beneath OU-2 and may increase the
potential for human exposure by increasing the long-term potential for contamination of the
lower aquifer. Although the lower aquifer is not currently contaminated, a connection
KN /NF:W. ROD/12-1S.9VF
6-4
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between the aquifers may lead to migration of contaminants into the lower aquifer east of
OU-2. Base production wells, which are upgradient of the plume, are not expected to
become contaminated based on fate and transport modeling. Dispersion of the free-phase and
contaminated shallow groundwater plume~''1ay impact the lower aquifer east of OU-2
because the upper and lower aquifers ma' ..:::ome connected due to the dissipation of the
confining layer. Future land use such as residential housing on Base property following
decommissioning could result in an increase in potential human health exposure due to the
use of contaminated groundwater from the upper aquifer or from the use of the lower aquifer
that may become contaminated in the long term.
This alternative would also not control exposure to the contaminated soil or reduce the
potential human health risk associated with this exposure. Migration of the contaminants
from soil to groundwater via infiltration should not adversely affect groundwater or surface
'~'ater quality because of the dry weather conditions (evaporation exceeds precipitation) at
OU-2. Migration via surface water runoff is not anticipated because benzene was not
detected in surface soils. Remedial response objectives may eventually be met due to natural
. contaminant attenuation processes; however, the presence of significant volumes of
contaminated soil below the upper 25-foot soil layer poses a long-term source of
contaminants that would be included in any assessment of potential natura: -:ontaminant
attenuation.
The residual risk, therefore, at the completion of this alternative could be equal to or greater
than the current risk for the future land use scenarios used in the baseline risk assessment.
The estimated present worth cost is $1.6 million based on $78,000 in capital and $314,000 in
yearly operation and maintenance (O&M) costs over a period of 30 years. Time to
implement this alternative is less than one month. The costs relate primarily to monitoring.
Alternative B: Institutional Actions and Capping
Institutional actions would include deed restrictions on potential transfers of affected Base
property for future land use and restrictions on construction of new water wells. This
alternative would also include periodic monitoring of existing groundwater wells. This
alternative would also install a concrete barrier over the four areas of contaminated soil at
KN/NEW.ROD/12-IS.92/F
6-5
-------
OU-2 (76,000 square feet), thus limiting exposure by potential receptors. There would be
deed restrictions on land use, and signs would be placed as additional institutional measures
.warning the community of potential dangers. Reviews would be performed every 5 years as
required by CERCLA Section 121(c) as long as contamination remains.
This alternative will provide a means of protecting the public from exposure to contaminated
groundwater by restricting use of the aquifers. Institutional actions have a limited
effectiveness, however, particularly for the long term because restrictions on land use or well
installation can be circumvented or not be enforced over time. It will not protect the
environment because the contaminants will spread and additional portions of the aquifer may,
without treatment, become unusable for drinking water. Because there is no discharge of
groundwater to surface water, environmental impact will be limited. It is possible that
natural attenuation will ultimately result in groundwater quality that meets action levels.
This alternative would provide a barrier against exposure to surface and subsurface soils and
would limit the potential for excavation or other soil disturbance activities that could result in
receptors contacting subsurface soils. This alternative would provide long-term protection if
the concrete cap is maintained periodically and if means are taken to avoid damage or
removal of capping. Because the contamination would not be removed or treated, there
would be continuing potential liability that exposure to contaminated soil could occur.
The residual risk after implementing this alternative would be equivalent to the risks
estimated under the current land use scenario used in the baseline risk assessment.
The estimated present worth cost is $2.3 million, based on capital costs of $0.731 million
and annual O&M costs of $0.314 million over a period of 30 years. Time to implement this
alternative is less than six months.
Alternative C: Groundwater Extraction, Air Stripping, and Injection plus Soil Vapor.
Extraction with In Situ Bioremediation
This alternative would consist of the following components:
.
Free-phase product and groundwater will be extracted using an estimated series
of up to 2 horizontal or 16 vertical extraction wells. The exact number, type,
and location of wells will be determined during the remedial design phase as a
result of aquifer tests conducted after well installations. There is approximately
KN/NEW. ROD/12-15-92/F
.6-6
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0.65 to 1.4 million gallons of free-phase product floating on top of the aquifer.
Total fluids pumping will be conducted at estimated flow rates between 30 and
60 gpm from the shallow aquifer using the extraction wells to maintain
hydraulic control of the plume and to reduce contamir.ant concentrations. There
is approximately 170 million gallons of groundwate~~;ontaminated with benzene
above the drinking water action level of 0.005 mg/L.
.
Fluids extracted from the ground will be passed through an oil/water separator
in order to capture all free-phase product prior to treatment of the water. Free-
phase product will either be reused by an approved vendor or disposed of at an
authorized off-site disposal facility.
.
Pretreatment, as needed, of the extracted groundwater will be conducted (e.g.,
precipitation, flocculation, clarification, f11tration, acid treatment, etc.) to
remove solids that may potentially interfere with the treatment for contaminants.
The specific system specifications will be developed from treatability studies
conducted during the remedial design phase, if required.
.
Pretreatment, as needed, of the extracted groundwater will be conducted (e.g.,
precipitation, flocculation, clarification, filtration, ion exchange, etc.) to reduce
the concentration of metals to action levels identified in ChaF~r 6.0 and
Appendix A of this document. Section 6.1.1 provides detail: for including this
treatment contingency. The detection of certain metals during the remedial
investigation may have been erroneous and additional sampling during the
remedial design phase will confirm or eliminate the need for this treatment.
Treatment system specifications will be developed from treatability studies
conducted during the remedial design phase, if this treatment is required.
.
Treatment of the extracted groundwater will be provided by twin air stripping
columns in series to reduce volatile contaminant concentrations to action levels
identified in Section 6 and Appendix A of this document. Contaminant
concentrations in groundwater requiring treatment are identified in Chapter 6.0
and Appendix A. Treatment will achieve greater than 99 percent removal of
volatile contaminants. The columns will be 2.5 feet in diameter with 18 feet of
packing each and 500 cfm of air flow each. .
.
Posttreatment, as needed, of the extracted groundwater will be conducted (e.g.,
liquid-phase carbon adsorption) to reduce semi-volatile organic concentrations to
cleanup levels identified in Chapter 6.0 and Appendix A of this document.
Section 6.1.1 provides details for including this treatment contingency. The
detection of certain phthalate compounds during the temedial investigation may
have been erroneous and additional sampling during the remedial design phase
will confirm or eliminate the need for this treatment. Treatment system
specifications will be developed from treatability studies conducted during the
remedial design phase, if this treatment is required.
KNINEW.RODI12-1S-92/F
6-7
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.
Treated groundwater will either be injected back intO the shallow aquifer to
assist in maintaining hydraulic control and to avoid depletion of the aquifer or
will be discharged to the Base wastewater treatment plant. A number of
factors will be evaluated to yield a decision by Parties to the FFA to inject
treated groundwater back into the aquifer andlor to discharge the treated
groundwater into the Base sanitary sewer for beneficial use on the Base golf
course. These factors include, but are not limited to the following: (1) the
results of aquifer measurements made during a given remediation period; (2)
the ability of injection wells to accommodate the extraction rate; and (3)
identified need for irrigation of the Base golf course. Based on current
estimates, four injection wells are planned. Their exact number, type, and
location will be detennined during the remedial design phase.
.
Soil treatment of the first 25 feet of soil (54,000 cubic yards) using
bioenhanced SVE will be provided. Vapor-phase nutrients will be introduced
to enhance biodegradation of soil contaminants. Other biological enhancements
(introduction of aerobic microbes, anaerobic microbes, aerophilic microbes,
liquid-phase nutrients, enzymes, and etc.) may be used if appropriate
treatability studies or equivalent data are reviewed and indicate that significant
remedial benefits would be accrued.
.
SVE will be implemented using approximately 64 extraction wells, 32 passive
vent wells, a vacuum system to remove 500 cfrn of air from wells, and a
nutrient addition system. Contaminant concentrations in soil requiring
treatment are identified in Chapter 6.0 and Appendix A. Bioenhanced SVE
will achieve greater than 94 percent reduction of benzene, and 64 percent
reduction of 1,4-dichlorobenzene. The exact number of wells will be
determined during remedial design.
.
Treatment of SVE and air stripping emissions will be provided using fume
incineration t~ meet ambient air quality and destruction and capture
requirements. Treatment will achieve greater than 99 percent reduction of
benzene, 1,4-dichlorobenzene, naphthalene, and toluene. In the event that the
fume incinerator cannot technically achieve an acceptable emission level of less
than three pounds per day of organic vapors, then a vapor-phase carbon
adsorption unit will be installed and used instead of the fume incinerator.
Process details for these alternative air emission treatment systems include:
Air stripping abatement by carbon - each stripping column would have
dual-bed, series adsorbers each containing 2,000 pounds of carbon with
carbon usage at 300 pounds/day
Air stripping abatement by fume incineration - unit would be rated at
1.2 million BTU/hr, 1,000 cfm, with fuel usage at 33.6 million BTU/day
KN/NEW.RODI12-16-92AJF
6-8
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SVE abatement by carbon - SVE system would have 2 dual bed systems
with each bed containing 11,000 pounds and using 6,800 pounds of carbon
per day in the first year, 1,500 pounds per day in the second year, and
1,200 pounds per day in the third year
SVE abatement by fume incineration - unit would be rated at 0.6 million
BTU/hr, 500 cfm, with fuel usage at 11 million BTU/day in the first year,
5.5 million BTU/day for the second and third years.
.
Institutional activities will be taken to impose restrictions on installation of new
wells and limiting soil excavation to 10 feet in depth at the ST-12 site.
Figure 6-1 presents a conceptual schematic of the treatment system depicting a vertical
extraction well for representative purposes. Monitoring of the treatment system (including
but not limited to all chemicals of potential concern) will be conducted and additional
treatment capacity will be added if contaminants not now believed to need treatment are
detected at levels above established action levels. The specific compliance monitoring
procedures will be developed during the remedial design phase by the USAF and regulatory
agencies to identify and trigger the need for any additional treatment. Monitoring of both the
groundwater and soil remediations will be performed to ensure that the contaminated zones
are being "remediated.
This alternative would also include the institutional actions of imposing restrictions on
installation of new wells and limiting soil excavation to 10 feet in depth.
A pilot demonstration test has been initiated to determine the effectiveness. and
implementability of horizontal wells and a treatability test initiated to determine the
effectiveness of anaerobic degradation of the contaminants.
More testing may be required for the emission abatement and the bioremediation portions of
this alternative.
Because of the volume of free-phase product and contaminated groundwater that may remain
after 5 years, a reevaluation would be performed at five year intervals in accordance with
CERCLA Section 121(c).
This alternative would substantially reduce the potential threat to human health posed by
exposure to contaminated groundwater at OU-2 by reducing levels of the chemicals of
KN/NEW.ROD/12-15-92IF
6-9
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.------.--.-.-.-
GROUNDWATER REMEDIATION
SOIL REMEDIATION
"'" . VQl.Anl[S
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I
FIGURE 6-;
WlWAMS AIR FORCE BASE
CONCEPTUAL SCHEMATIC FOR
ALTERNATIVE C
,
'\
,
."
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i
i
NOT TO SCALE
m INTERNATIONAL
TECHNOLOGY
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-------
potential concern in the groundwater. It would also prevent further environmental
degradation by arresting the spread of contaminants through the shallow aquifer and
minimizing any potential impact to the lower aquifer.
SVE with in situ bioremediation would reduce the levels of the chemicals of potential
concern in the 25 feet of soil, thus reducing the potential for human exposure and risk
associated with exposure to contaminated surface and subsurface soil. The concentration of
the chemicals of potential concern will meet action levels.
The residual risks for both groundwater and soil, as a result of this alternative, will pose a
HI of less than one and an ILCR within the target range 10 -4 to 10 ~, which will meet action
levels as specified in Appendix A.
Estimated present worth costs range from $7.9 to $21.1 million. Initial capital costs range
from $3.5 to $5.4 million, and annual O&M costs range from $0.6 to $8.0 million. Costs
are based on operating periods of 30 years for groundwater remediation and 3 years for soil
remediation. Differences in costs are due to variations in the extraction technology (vertical
or horizontal wells) and air pollution control technology (vapor-phase carbon adsorption or
fume incineration) that would be employed. Estimated time to implement this alternative is
approximately 18 to 24 months. Details of these cost estimates are provided in the OU-2 FS
Report.
Alternative D: Groundwater Extraction, Air Stripping and Injection plus On-Site Soil
Incineration
This alternative would consist of the following components:
.
Free-phase product and groundwater will be extracted using an estimated series
of up to 2 horizontal or 16 vertical extraction wells. The exact number, type,
and location of wells will be determined during the remedial design phase as a .
result of aquifer tests conducted after well installations. There is approximately
0.65 to 1.4 million gallons of free-phase product floating on top of the aquifer.
Total fluids pumping will be conducted at estimated flow rates between 30 and
60 gpm from the shallow aquifer using the extraction wells to maintain
hydraulic control of the plume and to reduce contaminant concentrations. There
is approximately 170 million gallons of groundwater contaminated with benzene
above the drinking water action level of 0.005 mglL.
.
Fluids extracted from the ground will be passed through an oil/water separator
in order to capture all free-phase product prior to treatment of the water. Free-
KN/NEW.ROD/12-1S-92IF
6-10
-------
phase product will either be reused by an approved vendor or disposed of at an .
authorized off-site disposal facility.
.
Pretreatment, as needed, of the extracted groundwater will be conducted (e.g.,
precipitation, flocculation, clarification, filtration, acid treatment, etc.) to
remove solids that may potentially interfere with the treatment for
contaminants. The specific system specifications will be developed from
treatability studies conducted during the remedial design phase, if required
.
Pretreatment, as needed, of the extracted groundwater will be conducted (e.g.,
precipitation, flocculation, clarification, filtration, ion exchange, etc.) to reduce
the concentration of metals to action levels identified in Chapter 6.0 and
Appendix A of this document Section 6.1.1 provides details for including this
treatment contingency. The detection of certain metals during the remedial
investigation may have been erroneous and additional sampling during the
remedial design phase will confirm or eliminate the need for this treatment.
Treatment system specifications will be developed from treatability studies
conducted during the remedial design phase, if this treatment is required.
.
Treatment of the extracted groundwater will be provided by twin air stripping
columns in series to reduce volatile contaminant concentrations to action levels
identified in Section 6 and Appendix A of this document. Contaminant
concentrations in groundwater requiring treatment are identified in Chapter 6.0
and Appendix A. Treatment will achieve greater than 99 percent removal of
volatile contaminants. The columns will be 2.5 feet in diameter with 18 feet of
packing each and 500 cfm of air flow each.
.
Posttreatment, as needed, of the extracted groundwater will be conducted (e.g.,
liquid-phase carbon adsorption) to reduce semi-volatile organic concentrations
to cleanup levels identified in Chapter 6.0 and Appendix A of this document
Section 6.1.1 provides details for including this treatment contingency. The
detection of certain phthalate compounds during the remedial investigation may
have been erroneous and additional sampling during the remedial design phase
will confinn or eliminate the need for this treatment Treatment system
specifications will be developed from treatability studies conducted during the
remedial design phase, if this treatment is required.
.
Treated groundwater will either be injected back into the shallow aquifer to
assist in maintaining hydraulic control and to avoid depletion of the aquifer or
will be discharged to the Base wastewater tteatment plant for beneficial use on
the Base golf course. A number of factors will be evaluated to yield a decision
by Parties to the FFA to inject treated groundwater back into the aquifer and/or
to discharge the treated groundwater into the Base sanitary sewer for beneficial
use on the Base golf course. These factors include, but are not limited to the
following: (1) the results of aquifer measurements made during a given
remediation period; (2) the ability of injection wells to accommodate the
extraction rate; and (3) identified need for irrigation of the Base golf course.
KNJNEW.RODn 2- 1l>-92AJf
6-11
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Based on current estimates, four injection wells are planned. Their exact
number, type, and location will be determined during the remedial design
phase.
.
Treatment of air stripping emissions will be provided using fume incineration
to meet ambient air quality and destruction and capture requirements.
Treatment will achieve greater than 99 percent reduction of benzene, 1,4-
dichlorobenzene, naphthalene, and toluene. In the event that the fume
incinerator cannot technically achieve an acceptable emission level of less than
three pounds per day of organic vapors, then a vapor-phase carbon adsorption
unit will be installed and used instead of the fume incinerator. Process details
for these alternative air emission treatment systems include:
Air stripping abatement by carbon - each stripping column would have
dual-bed, series adsorbers each containing 2,000 pounds of carbon with
carbon usage at 300 pounds/day
Air stripping abatement by fume incineration - unit would be rated at
1.2 million BTU{hr, 1,000 cfm, with fuel usage at 33.6 million.
BTU/day.
.
Soil to a depth of 25 feet will be excavated and thermally treated in a
transportable direct-fired rotary kiln. Contaminated soil constitutes 54,000
cubic yards in place (67,000 cubic yards when excavated). It will be necessary
to excavate an additional 79,000 cubic yards of clean soil to achieve a 1.0 to
1.5 s'ope on the sides of the excavation. The transportable rotary kiln will
have a feed rate of 10 tons per hour and will consume 200 to 500 gallons of
fuel per day to remove organic contaminants. Contaminant concentrations in
soil requiring treatment are listed in Table 6-2. Treatment will achieve greater
than 99 percent reduction in contaminant levels.
.
Institutional activities will be taken to impose restrictions on installation of new
wells and limiting soil excavation to 10 feet in depth at the ST-12 site.
Figure 6-2 presents a conceptual schematic of the treatment system depicting a vertical
extraction well for representative purposes. A transportable thermal treatment system would.
be used. Before initiating treatment of the soil, a test bum would be performed to
demonstrate that air pollution control permit limitations are being met. Monitoring of the
treatment system (including but not limited to all chemicals of potential concern) will be
conducted and additional treatment capacity will be added if contaminants not now believed
to need treatment are detected at levels above established action levels. The specific
compliance monitoring procedures will be developed during the remedial design phase by the
USAF and regulatory agencies to identify and trigger the need for any additional treatment
KNINEW.R0D/12-16-92AIF
6-12
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GROUNDWATER REMEDIATION
II
SOIL REMEDIATION
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t . CONCEPTUAL SCHEMA TIC FOR
ALTERNATIVE D
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-------
Monitoring of both the groundwater and soil remediations would be performed to ensure that
the contaminated zones are being remediated.
This alternative would also include the institutional actions of imposing restrictions on
installation of new wells and limiting soil excavation to 10 feet.
A pilot demonstration test has been initiated to determine the effectiveness and
implementability of horizontal wells. More testing may be required for the emission
abatement ponion of this alternative.
Because of the volume of free-phase product and contaminated groundwater that may remain
after 5 years, a reevaluation would be performed at five year intervals in accordance with
CERCLA Section 121(c).
This alternative would substantially reduce the potential threat to human health posed by
exposure to c'Jntaminated groundwater at OU-2 by reducing levels of the chemicals of
potential concern in the groundwater. It would also prevent further environmental
degradation by arresting the spread of contaminants through the shallow aquifer and
minimizing ~,y potential impact to the lower aquifer.
This alternative protects human health and the environment by providing a long-term,
permanent reduction in surface and subsurface soil contamination through removal and
incineration of contaminated surface and subsurface soils. This would essentially eliminate
organic contaminants in the 25-foot soil layer in OU-2 and avoid ~y potential future
exposure.
The residual risks for both groundwater and soil, as a result of this alternative, will pose a
HI of less than one and an ILCR within the target range 10 -4 to 10 -6, which will meet action
levels as specified in Appendix .~. .
Estimated present worth costs range from $20.8 to $24.3 million. Initial capital costs range
from $16.8 to $18.5 million, and annual O&M costs range from $0.4 to $0.6 million. Costs
are based on operating periods of 30 years for groundwater remediation and less than one
year for soil remediation. Differences in costs are due to variations in the extraction
technology (vertical or horizontal wells) and air pollution control technology (vapor-phase
carbon adsorption or fume incineration) that would be employed. Estimated time to
KN/NEW.ROD/12-1 S-92/F
6-13
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implement this alternative is approximately 24 to 36 months. Details of these cost estimates
are provided in the au - 2 FS Report.
KN/NEW.ROD/J2-1S-92IF
6-14
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7.0 Comparative Analysis of Alternatives
The final phase in the evaluation of remedial alternatives involved.a comparison of the
various alternatives against each other. The advantages and disadvantages of each alternative
are reviewed relative to each of the nine U.S. EPA evaluation criteria used in the previous
detailed analyses. Table 7-1 summarizes the evaluation process. For each criterion
discussed below, the apparent best alternative is identified first.
7. 1 Overall Protection of Human Health and the Environment
Alternatives C and D provide adequate protection for human health and the environment by
reducing the volume of contaminants in both groundwater and surface and subsurface soil.
Alternatives A and B do not provide long-term protection of human health and the
environment because neither would reduce the contamination in either medium nor prevent
migration of contamination within the media. By instituting site access controls, Alternative
B does provide greater protection than Alternative A because Alternative A provides no
treatment or controls.
7.2 Compliance with ARARs
ARARs for OU-2 are presented in Appendix A. Alternatives C and D would comply with
location-specific and action-specific ARARs as well as chemical-specific ARARs for the
chemicals of potential concern after sufficient treatment time has elapsed. Alternative B
would not meet ARARs for the chemicals of potential concern because there would be no
remediation of either surface and subsurface soil or groundwater. An ARARs analysis is not
required for Alternative A, a no action alternative.
7.3 Long- Term Effectiveness and Permanence
Alternatives C and D would achieve the highest degree of long-term effectiveness because.
chemicals of potential concern would be removed from the surface and subsurface soil and
groundwater and destroyed by thermal oxidation or biodegradation, either on site as part of
the remediation effort, or off site through use of recovered hydrocarbons from groundwater
as fuel. Alternatives A and B do not provide long-term protection of human health and the
environment because neither would reduce the contamination in either groundwater or soil
nor prevent migration of contamination within the media. By instituting site access controls,
Alternative B does provide greater protection than Alternative A because Alternative A
provides no treatment or controls. Alternative B would not reduce contaminants at OU-2 and
KNINEW.ROD/12-15-921F
.7-1
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Table 7-1. Comparison of Cleanup Alternatives
C. Groundwater
Extraction, Air Stripping, D. Groundwater
and Injection plus Soil Extraction, Air Stripping,
B. Institutional Vapor Extraction with In and Injection plus On-Site
Alternative A. No Action Actions and Capping Situ Bioremediation Soil Incineration
Overall Protection of Not protective Not protective Most protective Most protective
Human Health and the
Environment
Compliance with ARARs Does not comply Does not comply Complies Complies
Long-Term Effectiveness Not e Permanent Solution Not a Permenent Solution Achieves a Permenent and Achieves 0 Permanent and
and Permanence Effective Solution Effectiva Solution
Reduces Toxicity, Mobility No reduction No raduction Reduces Toxicity. Mobility. end Reduces Toxicity. Mobility. end
or Volume Volume Volume
Short- Term Effectiveness Not effective Moderately effective Most effective Effective
Implementability Most Implementabla Eesily Implement able Equipment Readily Aveileble; Equipment Readily Available;
Treatability Studies Requirad; Traatability Studios Required;
Permits and Approvels Permits and Approvals Necessery
Necessary
Cost (present Worth) $1.6 M $2.3 M $7.9 M to $21.1 M $20.8 M to $24.3 M
State Acceptance Not Acceptable Not Acceptabla Accepteble Acceptoble
Community Acceptance Not Acceptable Not Acceptable Acceptable with Questions Acceptable with Questions about
abeut Bioremediation Incineration
Remedial Duration (Years) > 100 > 100 >30 >30
KN/NEW.7AJt2.tS.92/F
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would rely solely on a cap and institutional controls to prevent exposure by blocking a
pathway to receptors. A concrete cap, although a relatively permanent means of preventing
exposure to surface and subsurface soil by workers and the general public if properly
installed and maintained, would not be :.;; reliable in the long term as removing the
contaminants.
Long-term management and monitoring of OU-2 would be comparable for Alternatives C
and D. Operation of the groundwater extraction and treatment system would be required for
at least 30 years in either inst.nce. Monitoring combined with institutional actions would
also be necessary to prevent use of groundwater in the area prior to achieving cleanup goals.
The reliability of the groundwater remediation for both alternatives is the same because the
same technologies would be employed for the same duration. Reducing th~ level of contami-
nants in groundwater to action levels throughout the shallow aquifer will depend on the rate
of release/dissolution of contaminants from the soil matrix that is currently saturated with the
free-phase hydrocarbon layer for either Alternative C or D. Review of either alternative
would be necessary at 5-year intervals to reassess the effectiveness and determine a projected
time to complete remediation.
7.4 Reduction of Toxicity, Mobility, o( Volume Through Treatment
Alternatives C and D would reduce the toxicity, mobility, and volume of contamination in
both groundwater and surface and subsurface soil versus Alternatives A and B, which would
not. For groundwater, the reduction in contaminant mass through thermal destruction or
adsorption and the reduction in volume of contaminated media through extraction would be
the same for Alternatives C and D because the same technologies would be employed for the
same duration. Incr~,ing the rate at which groundwater could be extracted could reduce the
duration for either alternative. Alternative D, which uses thermal treatment for surface and
subsurface soil, would achieve a greater reduction in contaminant mass than Alternative C,
using SVE with bioremediation, because the thermal treatment is more effective in removing
nonvolatile organic~rocessing of excavated soils is often more reliable than in situ
techniques. Both these alternatives would achieve the same reduction in volume of surface
and subsurface soil contaminated above action levels. Neither Alternatives A nor B accom-
plish a reduction in toxicity, mobility, or volume of contaminants because neither treat the
media.
KN/NEW.ROD/12-1S-92IF
7-2
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7.5 Short- Term Effectiveness
Alternative B can be implemented in the shonest time and technically, therefore, provides the
best shon-term effectiveness. With respect to soils, Alternatives C and D have comparable
time periods of approximately 1.5 to 3 years for implementation. The actual on-site
treatment time for Alternative D, thermal treatment, may be shorter than the time for
Alternative C, which would use a bioenhanced SVE system, to reduce surface and subsurface
soil contamination to health-based soil action levels. Both alternatives will be in compliance
with state and county air pollution control regulations. The incineration of vapor from soil is
not required to meet all substantive requirements of the Resource Conservation and Recovery
Act (RCRA) for an incinerator because the vapor-phase volatiles do not meet the definition
of a RCRA hazardous waste. The substantive RCRA incinerator requirements will apply for
the on-site incineration of soil that meets the RCRA definition of a hazardous waste. This
additional requirement will most likely lengthen the time required to meet all requirements.
The total time required to mobilize, install, and obtain approvals for Alternative D is
expected to be longer but would be offset by the longer operational period for Alternative C.
With respect to groundwater contamination, Alternatives C and D will take the same amount
of time to implement.
For Alternative B, dust and volatile organic emissions during cap installation would be
minimal because no major disturbance of the contaminated surface and subsurface soil would
be anticipated; however, if such disturbance did occur, preventative measures would be taken
to minimize fugitive dust emissions. Aiternative C, using bioenhanced SVE, would pose
somewhat higher risks to workers due to boring in contaminated soil and a minor potential
risk during operation due to temporary volatile emissions if the fume incineration system or
carbon adsorption system malfunctions. Alternative D would involve major excavation that
could release contaminants and would require controls to minimize exposure to workers and
Base personnel. Alternative D, thermal treatment, has the potential, although considered to
be very low, of releasing contaminants from the stack if incomplete combustion occurs.
Incineration also would pose a greater risk to workers than SVE and in situ bioremediation
because of the complexity, mechanical components, high temperatures of the incinerator
system, the storage and handling of liquid or gaseous auxiliary fuel, and the physical hazards
associated with excavation activities. There would be a minor risk related to groundwater
remediation for Alternatives C and D due to the potential temporary release of volatiles if the
fume incinerator or the vapor-phase carbon adsorption system on the air stripper exhaust
KN/NEW.ROD/12-IS-92/F
7-3
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malfunctioned, and due to potential fire or explosion related to storage and handling of
recovered hydrocarbons or fuel for the fume incinerator.
7.6 Implementability
Alternative A would require no implementation because it is the ~o-action alternative.
Alternative B would be the most easily implemented because design and placement of
concrete caps is a normal construction method. The caps could be expanded if additional site
monitoring data indicated the need. Periodic maintenance would be minimal for concrete
capping at OU:-2.
Alternatives C and D are comparable in terms of implementability and the groundwater
remediation component of each is the same. The technical feasibility of installing a success-
ful extraction/injection well. network and treatment system is rated moderate because there
are no known site or waste characteristics that represent significant problems for the
proposed technologies. The presence of certain mineral or organic constituents in the
groundwater could require either conditioning of the groundwater prior to air stripping or use
of an air stripper configuration that is more tolerant to fouling. Specific localized geologic
conditions could also affect the design and operation of the SVE system. Additional
groundwater composition data and geologic data would be necessary to verify specific
detailed design requirements that would ensure reliable operation. The equipment and
materials for the extraction and treatment syste; s are comr:::;rcially available. Horizontal
wells could present some technical difficulties, as noted in Section 3.0 of the OU-2 FS
Report. The technology that is recommended after the groundwater is extracted is a
commercially available technology. Only limited treatability or pilot testing appears to be
required to implement the groundwater components of Alternatives C or D as noted above.
Treatability or pilot test results from extraction methods using vertical and horizontal wells
will aid in designing the most cost-effective extraction system. Such a treatability study is
already under way at the site.
The issues that could affect successful implementation of the surface and subsurface soil
remediation component of Alternatives C and D are similar. Both alternatives will require
space for construction and operation of installed systems. Alternative D would be more
complex than Alternative C due to excavation and soil handling. Additionally, excavation
required in Alternate D would delay the installation of the groundwater treatment system and
would delay the extraction of the free product. Treatability or pilot testing would be
KNINEW.ROD/12-lS-921F
.7-4
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beneficial to optimize the SVE and in situ bioremediation system for Alternative C. The
equipment, materials, and other resources for both these alternatives are available, although
the SVE and in situ bioremediation system components for Alternative C would be less
specialized than those for Alternative D. Alternative D would have the most complex
operational requirements, including considerable labor for material handling and incinerator
operation and maintenance and utilities, particularly fuel; however, incineration offers the
opportunity to treat recovered hydrocarbons and avoid off-site shipment to a reclaimer or
other user. Alternative D could require treatability testing to verify processing requirements.
7.7 Cost
Table 7-2 summarizes the estimated capital, O&M cost, and present worth cost for each of
the four alternatives. The present worth ranges from $1.6 to $24.3 million. Present worth
costs for the groundwater remediation component range from 31 to 83 percent of the total.
Alternative B would have a present worth of $2.3 million, which is approximately $0.7
million higher than Alternative A, the no-action alternative, due to the cap construction cost.
Both alternatives would require long-term groundwater and periodic surface and subsurface
soil monitoring. Groundwater monitoring would be the major cost element. Both Alterna-
tives A and B would be less expensive than Alternative C, the next highest cost alternative;
however, potential future cost impacts associated with loss of aquifer use in the area and
restrictions on land use if chosen would greatly increase the Alternative A and B costs.
Estimates of aquifer and land use cost impacts are not within the scope of this investigation.
".
Alternative C would cost considerably less ($7.9 to $21.1 versus $20.8 to $24.3 million) than
Alternative D due to the relatively high processing (unit) cost for soils in an on-site incinera-
tor. The cost for groundwater remediation would be the same ($6.4 to $9.9 million) for both
alternatives. Capital cost for the extraction/injection well systems and treatment system
would represent approximately 29 to 52 percent of the estimated present worth for the
groundwater remediation component. The range of costs and percentages are due to the
variations in cost for vertical and horizontal extraction wells and the cost for fume incinera-
tion and vapor-phase carbon adsorption.
A cost comparison of the two air pollution abatement methods for both soil and groundwater
treatment showed the following:
KN/NEW. ROD/I 2- I 5-92/F
7-5
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TABLE 7-2. SUMMARY OF REMEDIAL ALTERNATIVE COST ESTIMATES
A B C D
.. GW Extraction, OW Extraction,
Capping Air Stripping, Air Stripping,
Plus & InJection, & Injection,
Institutional Plus SVE Plus On-Site Soli
Cost Component No Action Action In Situ Bio Incineration
Vertical Wells Horizontal Wells ' Vertical Wells Horizontal Wells
Vapor-Phase Vapor-Phase Vapor. Phase Vepor.Phase
Fume Carbon Fume Carbon Fume Carbon Fume Cerbon
Incineration Adsorption Incineration Adsorption Incineration Adsorption Incineration Adsorption
GROUNDWATER ACTION
t. Capital Costs $78,000 $78,000 $2,569,000 $2.480,000 $4,061,000 $3,972,000 $2,569,000 $2,480,000 $4,061,000 $3,972,000
2. Annual Oparating and $273,000 $273,000 $404,000 $643,000 $386,000 $625,000 $404,000 $643,000 $386,000 $625,000
Maintenance Costs (O&M)
3. Present Worth 01 08cM $1,152,000 $1,152,000 $3,811,000 $6,064,000 $3,635,000 $5,889,000 $3,811,000 $6,064,000 $3,635,000 $5,889,000
TOT AL PRESENT WORTH $1,230,000 $ t ,230,000 $6,380,000 $8,544,000 $7,696,000 $9,861,000 $6,380,000 $8,544,000 $7,696,000 $9,861,000
SOIL ACTION
,. Cepitel Costs $653,000 $975,000 $1,389,000 $975,000 $1,389,000 $14,394,000 $14,394,000 $14,394,000 $14,394,000
2. Annual Operating and $41,000 $41,000 $234,000 $7,312,000 $234,000 $7,312,000
Maintenence Costs (08cM)
3. Present Worth 01 O&M $385,000 $385,000 $587,000 $9,889,000 $587,000 $9,889,000
TOTAL PRESENT WORTH $385,000 $ 1.038,000 $1,562,000 $11,278,000 $1,562,000 $ t 1,278,000 $14,394,000 $14,394,000 $14,394,000 $14,394,000
TOTAL ACTION
1. Capital Costs $78,000 $731,000 $3,544,000 $3,869.000 $5,036,000 $5,361,000 $16,963,000 $16,874,1' ; '~:).OOO $18,366,000
2. Annual Operating and $314,000 $314,000 $638,000 $7,955,000 $620,000 $7,937,000 $404,000 $ 643,(Juv $386,000 $625,000
Maintenance Costs (O&MI
3. Present Worth 01 O&M $1,537,000 $1,537,000 $4,398,000 $15,953,000 $4,222,000 $15,778,000 $3,811,000 $6,064,000 $3,635,000 $5,88~r,()()
.. -., .. ' I
OVERALL TOTAL $1.615,000 $2,268,000 $7,942,000 $19,822,000 $9,258,000 $21,139,000 $20,774,000 $22,93f!,n, ,~. :;90,000 $2.; I
PRESENT WORTH j I
I
NOTE: A 10% discount rate and 30 vears was used to calculate ell 08cM present worth values except soil vapor extraction, which was calculated lor 3 vears.
KNfTA81EJ.2.KlSI12.11.D2/f
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.
Vapor-phase carbon adsorption O&M costs were higher than fume incineration
O&M costs for both soil and groundwater treatments
.
Vapor-phase carbon adsorption capital costs were higher than fume incineration
capital costs for soil treatment, but lower than fume incineration for
groundwater treatment. Specifically:
O&M costs for carbon are 60 % higher than fume incineration for
groundwater'
O&M costs for carbon are 300 % higher than fume incineration for soil
Capital costs for fume incineration are 3 % higher than carbon for
groundwater
Capital costs for carbon are 42 % higher than fume incineration for soil.
Table 7-2 presents a summary of remediation alternative cost estimates.
The cost for excavation and incineration for Alternative D would be approximately propor-
tional to the surface and subsurface soil volume. On the other hand, the cost sensitivity of
Alternative C does not relate directly to surface and subsurface soil volume because most of
the cost is fixed at the time of installation. Unit costs for Alternative D are more uncertain
than those for Alternative C. Reported cost experience on other similar projects indicates
that the unit cost for thermal treatment could range from + 50 percent. A moderate change
in the area over which surface and subsurface soil must be treated would greatly affect the
total cost of Alternative D while moderately affecting the cost for Alternative C. These
factors would be of importance for possible large variations in surface and subsurface soil
treatment volumes.
7.8 State Acceptance
U.S. EPA Region IX, ADWR, and ADEQ have been involved in the technical review of the
OU-2 FS and the development of the proposed plan and ROD. The U.S. EPA and the State
agree with the selected alternative as presented in this decision document.
7.9 Community Acceptance
Community reaction to the selected remedial action has been positive. During the public
comment period, several comment letters were received. The comments, along with
KN/NEW.ROD/12.1 S.92fF
7-6
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questions raised during the public meeting, primarily addressed cleanup extent and methods.
The community seemed most concerned about:
.
The use of bioremediation to remediate the soils
.
Limiting soil cleanup to 25 feet
.
The selection or elimination of certain technologies or processes
.
The extraction process to be employed for groundwater removal from the
aquifer
.
The role that the public will play in the remedial action process.
The Responsiveness Summary (Chapter 10.0) provides a thorough review of the public
comments received on the Proposed Plan and the Feasibility Study, and on the USAF's
responses to the comments received.
KNfNEW. ROD/12-1 S-92IF
7-7
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8.0 The Selected Remedy
The selected overall remedy for this ROD is Alternative. C. The specific components of the
alternative were presented in Section 6.2. It meets all nine evaluation criteria, as shown in
Table 7-1. Details of the selected remedy will be finalized during the remedial design phase.
The selected remedy will provide the greatest level of effectiveness that is technically and
economically feasible. The criterion of protection of human health and the environment is
appropriately balanced with both effectiveness and technicaVeconomic feasibility. Appendix
B contains the preliminary estimates of capital costs and O&M costs of the selected remedy
(Alternative C). Final cost estimates may vary from the estimates presented due to changes
that may occur as a result of treatability tests and differences between assumed and actual
environmental factors at the time of remedial action design and construction. These data. in
general, will result in modifications during the engineering design process. The hydraulic
gradient control system and system performance evaluation and schedule will be developed
during the remedial design process.
Residual risk from this selected alternative, although qualitatively addressed in this ROD in
Sections 6.0 and 7.0, will be addressed quantitatively during the comprehensive baseline risk
assessment for the entire Base to be presented in the Base-wide RIlFS repons and the ROD.
Several contingency issues are associated with this selected alternative. These are broken into
issues dealing with the groundwater portion of this alternative and issues dealing with the soil
portion of this alternative. The following sections address these contingencies.
8.1 Groundwater Remediation
The selected alternative will remove free-phase product and contaminated groundwater via
extraction well~ treat the groundwater via air stripping to reduce concenttations of chemicals
of potential concern to below action levels established in Appendix A, Table A-3, and inject
treated groundwater back into the aquifer through injection wells and/or discharge it to the
Base sanitary sewer for beneficial use on the Base golf course. Figure 6-1 shows the
conceptual schematic of this process. The decision-making process to determine specific
contingencies is specified below.
KN/NEW.R0DI12-1~92AJF
8-1
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1'-
8.1.2.3 EmIssIon Abatement
The selected remedy will control emissions from the snipping column with fume incineration.
However, the selected remedy calls for the contingent U::.~ of vapor-phase carbon adsorption to
control emissions in the event that the fume incinerator cannot technically achieve an
acceptable emission level of less than three pounds per day of organic vapors. Figure 8-1
depictS this decision poinL In the event that ....,,-?Or-phase carbon adsorption is used, design
considerations will be based on C<:7~ collected d~:i.ng the pilot demonstration. This data
includes O&M requirementS, loading rates, untreated vapor concentrations, and stack
emissions.
8.1.2.4 Posttreatment
Posttreatment of groundwater after air snipping to remove semi-volatile contaminantS is not
planned; however, sampling will be conducted during the remedial design phase to ascertain
the need for posttreatmenL As detailed in Section 6.1.1, the need to provide posttreatment for
phthalate compounds is questionable because the results of prior sampling may be erroneous
or ~:1conclusive. Specific sampling will be cGnducted du; ',g pilot studies to conn:mt the
concentrations of this potential contaminant. Figure 8-1 is a flow diagram showing these
decisions pointS in the process.
8.1.2.5 Inject/on
The selected remedy calls for treated groundwater to be injected into a series of wells or, with
the conC11lTence of the Parties to the FFA, discharged into the Base's sanitary sewer for
beneficial use on the Base golf course. A number of factors will require evaluation in the
event that discharge to the sewer is proposed for all or a portion of the treated water for a
stated period of time. These factors include, but are not limited to the following: (1) the
resultS of aquifer measurementS made during a given remediation period; (2) the ability of
injection wells to accommodate the extraction rate; and (3) identified need for irrigation of the
Base golf course. The number, configuration, and specific locations of the injection wells
will be determined with data acquired during the pilot demonstration study. Figure 8-1 shows
this decision node.
8.1.3 Information Summary
Data from the OU-2 RI/FS and a pilot demonstration will be used to make the above
decisions. Additional information needed to fill data gaps will be collected. This data will be
used during the remedial design phase. The USAF will continue to collect data during the
KN,INEW.ROOO2-16-92AJF
8-2
-------
Posttreat
Base
Sanitary
Sewer
Stop
Recover
Groundwater
Figure 8-1.
409735/12-15-921TK10.COO
Treated
Groundwater
Water
Yes
Injection
Stop
No
Oil/Water
Separator
No
Air Stripper
Treatment
Yes
Vapor
Treatment
Stop
Vertical
Wells
Yes
Yes
No
Pretreat
Pretreat
Vapor-
Phase
Carbon
Vapor
Treatment
Stop
Groundwater Treatment Flow Diagram
-------
8. 1.2.3 Emission Abatement
The selected remedy will control emissions from the stripping column with fume
incineration. However, the selected remedy calls for the contingent use of vapor-phase
carbon adsorption to control emissions in the event that the fume incinerator cannot
technically achieve an acceptable emission level of less than three pounds per day of organic
vapors. Figure 8-1 depicts this decision point. In the event that vapor-phase carbon
adsorption is used, design considerations will be based on data collected during the pilot
demonstration. This data includes O&M requirements, loading rates, untreated vapor
concentrations, and stack emissions.
8.1.2.4 Posttreatment
Posttreatment of groundwater after air stripping to remove semi-volatile contaminants is not
planned; however, sampling will be conducted during the remedial design phase to ascertain
the need for posttreatment. As detailed in Section 6.1.1, the need to provide posttreatment
for phthalate compounds is questionable because the results of prior sampling may be
erroneous or inconclusive. Specific sampling will be conducted during pilot studies to
confirm the concentrations of this potential contaminant. Figure 8-1 is a flow diagram
showing these decisions points in the process.
8. 1.2.5 Injection
The selected remedy calls for treated groundwater to be injected into a series of wells or,
with the concurrence of the Parties to the FFA, discharged into the Base's sanitary sewer. A
{lumber of factors will require evaluation in the event that discharge to the sewer is proposed
for all or a portion of the treated water for a stated period of time. These factors include,
but are not limited to the following: (1) the results of aquifer measurements made during a
given remediation period; (2) the ability of injection wells to accommodate the extraction
rate; (3) the minimum volume of water needed at the Base's wastewater treatment plant to
remain in operation; and (4) identified Base treated wastewater reuse needs, such as
irrigation of the Base golf course. The number, configuration, and specific locations of the
injection wells will be determined with data acquired during the pilot demonstration study.
Figure 8-1 shows this decision node.
8. 1.3 Information Summary
Data from the OU-2 RIfFS and a pilot demonstration will be used to make the above
decisions. Additional information needed to fill data gaps will be collected. This data will
be used during the remedial design phase. The USAF will continue to collect data during the
KNINEW.ROD/12-16-92IF
'8-3
-------
operation of the selected remedy to be used in evaluations for the most effective and
beneficial disposal method for the treated water.
8.2 50il Remediation
SVE with bioenhancement, as shown in the Figure 6-1 conceptu31 schematic, is the selected
remedy for soil remediation. The remedy will use in situ treatment technologies to reduce
contaminant levels in the top 25 feet of soil to below action levels. To optimize the
treatment, biological enhancements (introduction of aerobic microbes, anaerobic microbes,
aerophilic microbes, liquid-phase nutrients, enzymes, and etc.), in addition to the
introduction of vapor-phase nutrients, may be used if appropriate treatability studies or
equivalent data are reviewed and indicate that significant remedial benefits would be accrued.
As a result, several decision points, depicted on Figure 8-2, show minor variations on the
same fundamental treatment processes. Decisions regarding which, if any, of these
variations will be used will be made during remedial design phase based on feasibility,
implementability, economics presented in the FS, the data resulting from a bioremediation
treatability studies, and other data that may be appropriate.
8.2. 1 Decision Process
Figure 8-2 shows the decision process for treatment of contaminated soils shallower than 25
feet in depth. This figure also shows the decision points that will be considered during the
design phase for soil treatment remediation. Each decision point requires data that has been
collected in the OU-2 RI/FS, the treatability study, or will be independently gathered.
There are approximately 54,000 cubic yards of soil from the surface to a depth of 25 feet
that is contaminated with constituents of JP-4 and will require remediation. In situ SVE with
bioenhancement will be the specific type of treatment but there will be several decision points
during the design phase to optimize the effectiveness of the design. Currently there is a
treatability study underway to determine the effectiveness of bioremediation of these soils.
The results of this . study will be used during the remedial design phase to finalize the
implemented remediation.
8.2.2 Decision Points
8.2.2.1 Microbe Selection
Aerobic, naturally-occurring microbes are specified at this time for biotreatment; however, a
decision point has been established to determine if anaerobic microorganisms might be a
KN/NEW.ROD/12.16-92/F
8-4
-------
Soil
Preparation
SVE Enhanced
Bioremediation
Anaerobic
Microbes
4lJ9735/12-15-92/TK1 J.COR
No
Slop
Figure 8,,2.
Ves
Nutrient
Delivery
Ves
Nutrient
Delivery
Yes
Extract Vapors
from
Pore Space
No
Vapor
Treatment
Stop
Soil Treatment Flow Diagram
Enhancement
Addition
Vapor-
Phase
Carbon
Vapor.
Treatment
Stop
-------
more effective degradation option. Data from the ongoing treatability study at the Base will
be used to aid in this evaluation. In addition, either type of microbe could be utilized by
either stimulating naturally-occurring microorganisms or by inoculation of additional
microbial strains to potentially make treatment more effective by accelerating treatment time
or decreasing final contaminant concentrations. A determination of whether to use aerobic or
anaerobic microbes to degrade the contaminants and whether those microbes are naturally-
occurring or inoculated will be made considering data for the microorganism's effectiveness
in degrading the contaminants and on the implementability of delivering adequate nutrients to
the microorganisms in the type of soil to be treated. Due to biological constraints, aerobic
and anaerobic microbes cannot flourish under the same conditions, so a selection of one or
the other will be made. Additional data as needed will be acquired through laboratory tests.
8.2.2.2 Nutrient Delivery System
Nutrients will be delivered to the microbes via either a vapor-phase delivery system, as
currently selected, or via a liquid-phase delivery system. There will be a decision point
regarding the delivery of nutrients to the matrix containing the microorganisms and the
contaminants as shown in Figure 6-3. The use of anaerobic microorganisms would only use
liquid-phase delivery due to the nature of the nutrients required. The use of aerobic
microorganisms can use either liquid- or vapor-phase delivery. A determination of the most
effective delivery method will be based on the type of microorganism to be stimulated and
the delivery requirements, effectiveness, availability of the nutrients, and economics. Data to
make this decision will be acquired through treatability and/or laboratory tests.
8.2.2.3 Enhancement Addition
No addition of enhancing agents is now required for the chosen alternative. The USAF will
consider the benefit of adding an enhancement agent to accelerate the bioremediation process.
This enhancement agent could be enzymes, additional microbes, chelants, surfactants, etc.
Additional microbial strains to enhance the already stimulated naturally-occurring microbes
would be considered an enhancement, not a selection of microbes. Determination of the
effectiveness and economics of using enhancement agents will be made during the remedial
design phase and it will be based on data acquired through treatability and/or laboratory
tests.
8.2.2.4 Emission Abatement
The selected remedy will control emissions from SVE treatment with fume incineration;
however, the selected remedy also calls for the contingent use of vapor-phase carbon
KNINEW.ROD/12-16-92/F
8-5
-------
adsorption to control emissions in the event that the fume incinerator cannot technically
achieve an acceptable emission level of less than three pounds per day of organic vapors.
Figure 8-2 depicts this decision point. In the event that vapor-phase carbon adsorption is
used, design considerations will be based on data collected during the pilot demonstration.
This data includes O&M requirements, loading rates, untreated vapor concentrations, and
stack emissions.
8.2.3 Information Summ..-::ry
Data from the OU-2 RIfFS, a pilot demon~ .. tion, and labc;ratory and treatability studies will
be used to make the above decisions. Addiu..' ':l! information needed to fill data gaps will be
collected. This data will be used during the remedial design phase. The USAF will continue
to collect data during the operation of the selected remedy to direct process refinements.
KNfNEW.ROD/12-16-92IF
.8-6
-------
9.0 Statutory Determinations
Under Section 121 of CERCLA, the selected remedy must be protective of human health and
the environment and must comply with all ARARs.
The selected remedy also must be cost-effective and utilize permanent solutions and alterna-
tive treatment technologies to the maximum extent practicable. Remedies that employ
treatment that permanently and significantly reduce the volume, toxicity, or mobility of
hazardous wastes as a major part of the remedy are preferable. How the selected remedy
meets these requirements is discussed below.
The selected remedy represents the best balance of trade-offs among alternatives with respect
to peninent criteria, given the scope of this action.
9. 1 Protection of Human Health and the Environment
The selected remedy protects human health and the environment through extraction of
contaminated groundwater and free-phase product and removal/treatment of VOCs by air
stripping and by remediating the first 25 feet of soils with SVE and bioremediation. The
volatile contaminants from the air stripper and the SVE system will be transferred to the air,
removed by either carbon adsorption or fume incineration, then disposed of either at an
approved carbon regeneration facility or by combustion in the fume incinerator. The
recovered free-phase product will be disposed of at an approved disposal/recycling facility.
No adverse affects as a result of cross media transfer are expected. Control of emissions
using either vapor-phase carbon adsorption or fume incineration will adequately control any
potential exposure risk.
Extraction and treatment of groundwater will eventually reduce concentrations of
contaminants in groundwater to levels at or below the action levels. SVE with in situ
bioremediation will also eventually reduce concentrations of contaminants in the top 25 feet
of soil to levels at or below the action levels. Because the action levels are intended to be
protective of human health and the environment, the magnitude of residual risk from
exposure to groundwater and soil should be reduced from those levels presented in the
baseline risk assessment for future land use (Tables 5-3 and 5-5) to acceptable levels. The
task-based action levels (presented in Appendix A) are based on a residential exposure model
and are calculated based on a cancer risk not to exceed 1 x 10 -6 or a HI not to exceed 0.25
KN/NEW.ROD/12-1S-92/F
9-1
-------
for individual chemicals. These target risk levels are used to account for the possibility of
exposure to multiple chemicals of potential concern from other pathways and sources.
9.2 Attainment of ARARs
The selected remedy will achieve the ARARs for the groundwater, soils, and air emissions.
These ARARs are presented in detail in Appendix A.
9.3 Cost Effectiveness
The selected remedy (Alternative C) was evaluated for cost effectiveness against the other
three alternatives (A, B, and D). The selected remedy would require an overall shorter
period of time (including implementation and remediation) and should cost considerably less
than Alternative D, the only other alternative that provides overall protection of human health
and the environment and complies with ARARs (Table 7-1). The remedy will provide
effectiveness proportional to the cost of the remedy given the operation and maintenance and
present worth cost for the protection of human health and the environment.
9.4 Utilization of Permanent Solutions and Alternative Treatment Technologies or
Resource Recovery Technologies to the Maximum Extent Possible
The selected remedy is the design concept that best represents the tradeoffs among alterna-
tives with respect to the pertinent criteria, especially the balancing criteria of implementabil-
ity, short-term effectiveness and cost. Contingencies addressed in the selected remedy
(Section 6.1.1) are compatible with its conceptual design; detailed design issues will be
resolved during the remedial design phase. Contaminants will be permanently removed and
eliminated by groundwater extraction and surface treatment. Contaminants will be disposed
off-site at an approved regeneration facility or destroyed through the fume incineration
process.
Resources will be conserved to the maximum extent possible using the selected remedy.
Treated water will be injected back into the shallow aquifer and/or discharged to the Base
wastewater treatment plant. Contaminant recovery will be implemented to the maximum
extent possible without losing the removal efficiency of the abatement unit.
9.5 Preference for Treatment as a Principal Element
The requirement that treatment be a principal element of the remedy is satisfied. This
operable unit action is consistent with planned future actions, to the extent possible.
KN/NEW. ROD/12-15-92/F
9-2
-------
Appendix A
Applicable or Relevant and Appropriate Requirements (ARARs)
KNINEW.COV/12-1S-92/F
-------
1-
ARARs Update
The chemical-specific, action-specific, and location-specific ARAR tables that were presented in the
OU-2 FS Report and Proposed Plan have been revised. The most recent versions are presented in this
appendix of the OU-2 ROD. The specific ARAR values affected include the Arizona HBGL for
Ingestion of Contaminants in Soil and Groundwater, which were in a preliminary draft stage when the
previous documents were published. These HBGLs have now been issued final and the ARAR tables
in Appendix A have been revised to show the final values. In addition, values for several Federal and
State MCLs, promulgated or proposed, have been included.
The current versions of these tables supercede any previous versions issued in other documents,
including the OU-2 FS and Proposed Plan. The only value change that affected the chemicals of
potential concern and the subsequent evaluation of alternatives was the lowering of the groundwater
action level of naphthalene from 0.69 mg/L to 0.028 mg/L. This new value was included in the
evaluation of the alternatives, but did not change any conclusions. The conceptual process design used
to determine cost for groundwater remediation may require revision prior to remedial design to expand
the air stripping system to remove the incremental concentrations of naphthalene.
KNINEW.COV/12-1S.92/F
-------
Table A-1. list of Contaminants of Potential Concern in Groundwater and Potential Applicable or Relevant and
Appropriate Requirements and Other Potential Criteria to be Considered (all values are mg/l)
Potential ARARs Other Potential Criteria To Ba Considerad nBCI
Risk-Basad U.S.EPA Heallh Advisoriesl
Calculated
Water 'Arizone Allowable Longer Term
Reinjection Faderal Federal Health-Based Concantration 1-Day 10-Day Lifetime
Contaminant Federal Federal Arizona Clean-Up Proposed Proposed Guidance in 10 kg 10 kg 70 kg
MCL8 MCLG MCLq Standards. MCL MCIG Levelb Groundwatar 10 kg 70 kg
Benzene 0.005 0.005 0.005 0.0012 0.006 0.235' 0.235r N/AQ N/AQ N/AQ
bis( 2- ethylhexyllphthalate 0.006" 0" 0.0025 0.0129
1, 2-Dichloroethene 0.005 0 0.005 0.005 0.00038 0.002 0.74h.i 0.74h.i 0.74 2.6 N/AQ
Ethyl benzene 0.7 0.7 N/Ak 0.7 0.7 1.72 32 3.2 N/Ah N/Ah 0.68
Methylene chloride 0.005" 0" N/Ak 0.0047 0.024
2-Methylnephthalene N/Am
2-Methylphenol 0.87
4-Melhylphenol 0.87
Naphthalene 0.028 0.69 O.Sh.' 0.5 0.4 1 0.02
Phenol 4.2 10.5
Tetrachloroethene 0.005 0 N/Ak 0.005 0.0007 0.0035 2.0'.h 2.0 1.4 5.0 N/AQ
Toluane 1.0 1.0 N/Ak 1.0 1.4 3.5 21.5 3.46h.1 3.46h',1 3 ,46h. I 2.42
Trichlorofluoromothono N/Ak 2.1 S.3 374 7.1 3.49 12.2 2.44
Xylenos 10.0 10.0 N/Ak 10.0 14 34.5 36h.; 36h.; 36 125 12.53
Antimony 0.006" 0.006" 0.0028 0.007
Chromium III 0.1d 0.1d 0.1d 0.1d 0.1d 17.5 1 .4h. '. d 1.4d 0.24d 0.84d 0.12d
Chromium VI 0.1d 0.1d 0.1d 0.1d 0.1d 0.087 1 Ah. ,. d 1.4d 0.24d 0.84d 0.12d
Copper 1.3° 1.3 N/Ak 1.3 1.3P 1.3 0.65
Lead 0.5 0 0.5 0.005 0.015P 0.005 0.012
Nickel 0.1" 0.1" 0.14 0.35 1.0' 1.0' 0.16h.1 0.58h.1 0.17
(Page 1 of 2)
KNINEW,A.1112-10-92/F
-------
Table A-1
(Page 2 of 2)
Potential ARARs Other Potential Criteria To Be Considered nBC)
-_.~
Risk-Based U.S.EPA Health Advisoriesl
Calculated
Water Arizona Allowable Longer Term
Reinjection Federal Federal Health-Based Concentration 1-Day 10-Day Liletime
Contaminant Federal Federal Arizona Clean-Up Proposed Proposed Guidance in 10 kg 10 kg 10 kg 70 kg 70 kg
MCL' MCLG MCLq Standards' MCL MCLG Levelb Groundwater
Silver 0.05 0.05 0.05 0.05 0.053
Zinc N/Ak 1.4 3.5
'U.S. EPA, 40 CFR Parts 141,142,143.1991.
bArizona Human Health-Based Guidance Levels for Ingestion of Conteminents in Drinking Water and Soil. June 1992.
"Not a source MCL . MCL is in distribution system.
dTotal Chromium
0ADEQ, Aauifer Water Quality Standards. to be enacted in early 1993.
'Use of the 10-day HA for a 10-kg child is recommended.
UNot calculated or recommended because of carcinogenic potential of contaminant.
hData ara insufficient to calculate HA.
;Based on Drinking Water Equivalent Level.
IUse of Longer Telm HA lor a 10-kg child is recommended.
kMonitor in accordance with R 1 8-4-223.F and R1 8-4-223.B.5. Public and Semi-Public Weter Supply Systems Rules, ADEQ, August 11. 1989.
IU.S. EPA, Office of Drinking Water Health Advisories. Reviews of Environmental Contamination and Toxicity. 1988- 1 990.
mNo U.S. EPA approved toxicity informetion is available for developing an action level for this compound.
"New linal drinking water standards effective Jenuary 1994. FR, July 17. 1992.
PFederal treatment requirements effective December 7, 1992.
qArizona Aquiler Water Quality Standards. May 1992.
ADEQ . Arizona Department 01 Environmental Quality
MCL . Maximum Contaminent Level
MCLG . Maximum Contaminant Level Goal
SDWA . Safe Drinking Water Act
U.S.EPA Health Advisories:
1-day/10 kg. Concentration of compound in drinking water that could pose a risk if consumed by a 10 kg child for 1 day.
10-day/10 kg - Concentration of compound in drinking water that could pose a risk is consumed by a 10 kg child for 10 days.
Longer Term!10 kg - Concentration 01 compound in drinkil1g water that could pose a risk if consumed by a 10 kg child lor more than 10 days.
Longer Term170 kg. Concentration 01 compound in drinking water that could pose a risk if consumed by a 70 kg adult for more than 10 days.
Lifetime/70 kg - Concentration of compound in drinking watar that could pose a risk If consumed by a 70 kg adult for a liletime.
KN/NEW .A-I/12-1 0-92/F
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Table A-2. List of Contaminants of Potential Concern in Surface and
Subsurface Soils and Potential Applicable or Relevant and
Appropriate Requirements and Other Potential Criteria to be Considered
Risk-Based
Arizona Health-Based Calculated Allowable Background
Soil Guidance Level" Concentration in Soil Levels in Soilc
Contaminant (mg/kg) (mg/kg) (mg/kg)
Surface and Subsurface Soil (top 25 feet)
Acetone 12,000 13,000 ---...
bis (2 -ethylhexyl) phthalate 97 95 ---
Cadmium 58 65 ...---
Subsurface Soil (, foot to 25 feet deep)
Benzene 47 45 ----
Chlorobenzene 2,300 2,550 ----
1,2-Dichlorobenzene 10,000 11 ,500 ...---
1,3-Dichlorobenzene 10,000 NAb' ----
1 A-Dichlorobenzene 1,200 55 ----
Ethyl benzene 12,000 13,000 ...---
2-Hexanone NAb ----
Methylene chloride 180 180 ...---
2 -Methylnaphthalene NAb ----
4-Methyl-2-pentanone 0.95 ----
Naphthalene 470 520 ----
Phenol 70,000 76,000 ---
Toluene 23,000 25,500 ---
Xylenes 230,000 255,000 ---
Antimony 47 52 -
Lead 84 90 15.0 - 150.0
Surface Soil (top 1 foot)
Di-n-butylphthalate 12,000 13,000 ----
Diethylphthalate 94,000 102,000 ...---
Beryllium 0.32 0.3 1.0-1.5
'From: Arizona Dapartment of Environmental Quality, Guidance levels for Contaminants in Drinkina
Water and Soil. June 1992.
"No EPA approved toxicity information is available for developing an action level for this compound.
-------
Table A-3: Chemical Specific ARARs
List of Contaminants of Potential Concern in Groundwater and Their Action levels
Action Level.
Contaminant Relevant and Criteria To Be Citation
Applicable Appropriate Considered
/mg/U /mg/L) (mg/L)
Benzene 0.005 Federal MCL
bis (2 -ethylhexyl) phthalate 0.006 Federal MCL, effective January 1994
1,2-Dichloroethane 0.005 Federal MCL
Ethyl benzene 0.7 Federal MCL
Methylene chloride 0.005 Federal MCL, effective January 1 994
2-Methylnaphthalene No approved toxicity information
available to compute action level
2-Methylphenol 0.87 USAF risk-based allowable
concentration
4-Methylphenol 0.87 USAF risk-based allowable
concentration
Naphthalene 0.028 AZ HBGL
Phenol. 4.2 AZ HBGL
Tetrachloroethene 0.005 Federal MCL
Toluene 1.0 Federal MCL
T richlorofluoromethane 2.1 AZ HBGL
Xylenes 10.0 Federal MCL
Antimony 0.006 Federal MCL, effective January 1994
Chromium III 0.1 Federal MCL
Chromium VI 0.1 Federal MCL
Copper 1.3 EPA OSWER June 24, 1990 (values
effective December 19921
Lead 0.015 EPA OSWER June 24, 1990 (values
effective December 19921
Nickel 0.1 Federal MCL, effective January 1994
Silver 0.05 Federal MCL
Zinc 1.4 AZ HBGL
. These action levels apply to both effluent treatment standards and final in situ standards.
KN/NEW.A-3/12-16-92/F
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Table A-4: Chemical Specific ARARs
List of Contaminants of Potential Concern in Soil and Their Action Levels
Action Level a
Criteria To Be
Contaminant Considered Citation
(mg/kg)
Surface and Subsurface Soil (top 25 feetl
Acetone 12.000 AZ HBGL
bis (2 -ethylhexy I) phthalate 95 USAF risk-based allowable concentration
Cadmium 58 AZ HBGL
Subsurface Soil (1 foot to 25 feet deep)
Benzene 45 USAF risk-based allowable concentration
Chlorobenzene 2.300 AZ HBGL
1,2-Dichlorobenzene 10,000 AZ HBGL
1,3-Dichlorobenzene 10,000 AZ HBGL
1 A-Dichlorobenzene 55 USAF risk-based allowable concentration
Ethyl benzene 12,000 AZ HBGL
2-Hexanone No approved toxicity information available to compute action
level
Methylene chloride 180 AZ HBGL
2-Methylnaphthalene No approved toxicity information available to compute action
level
4-Methyl-2-pentanone 0.95 USAF risk-based allowable concentration
Naphthalene 470 AZ HBGL
Phenol 70.000 AZ HBGL
Toluene 23,000 AZ HBGL
Xylenes 230,000 AZ HBGL
Antimony 47 AZ HBGL
Lead 15-150 Background Concentrations
Surface Soil (top 1 foot)
Di-n-butylphthalate 12,000 AZ HBGL
Diethylphthalate 94,000 AZ HBGL
Beryllium 1.0-1.5 Background Concentrations
a These action levels apply to both soil treatment standards and final in situ standards.
KN/NEW.A.4/12.16-92/F
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Table A-5. Location-Specific Applicable or Relevant and Appropriate Requirements
and Other Criteria to be Considered
Location Requirementlsl Prerequisitelsl Citation Comments AO RARb TBCe
Within area where action Action to recover and Alteration of terrain that National Archaeological and Artifacts have B, C.
may cause irreparable preserve artifacts. threatens significant Historical Preservation Act been found in D
harm, loss, or destruction scientific, prehistoric, historic, (16 USC Section 4691; 36 areas near OU-2
of significant artifacts or archaeological data. CFR Part 65 but not in OU-2.
Hazardous waste site Actions to limit worker Construction, operations .;": 29 CFR 1910.120 8, C,
exposure to hazardous maintenance, or other D
wastes or hazardous activities with potential
substances, including worker exposure.
training and monitoring.
. Applicable Requirements for Alternatives 8, C. or D as noted.
b Relevant and Appropriate Requirements for Alternatives B, C, or D as noted.
e Criteria To Be Considered for Alternatives B, C, or D as noted.
KN/NEW.A.5/12-15-92/F
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Table A-G.
Action-Specific Applicable or Relevant and Appropriate Requirements
and Other Criteria to be Considered
(Page 1 of 5)
Action Requirement(s) Prerequisite(s) Citation Comments AO RARb TBC"
Air Stripping RCRA standards for control of emissions RCRA hezardous waste 40 CFR Subparts AA & The stenderd requires reduction C
of volatile orgenics. 1111 from .production accumulator
vessels. end leak detection end
repair programs. Product
accumulator vessels include air
strippers.
Air Emissions Control of air emissions of volatile Emission of VOCs, particulates, and Maricopa County Air B,
Control During organics, particulates, and gasaous gaseous air contaminants Quality Standards C,
Ramediation contaminants. (Rules 200, 210. 220. D
3201 as dictatad by the
Clean Air Act
Well Installation Arizona Groundwatar Management Act Installation 0' walls and withdrawal ARS 45-454.01 C. B
and Groundweter of groundwater D
Withdrawal
Container Containers of hazardous waste must be: RCRA hazardous waste (listed or 40 CFR 264.171 These requirements are applicable B.C, D
Storage characteristicl held for a temporary or relavant and appropriate for any
(On-Site) . Maintained to good condition period belore treatment, disposal, or 40 CFR 264.172 contaminated soil or groundwater
. Compatible with hazardous waste to storage elsewhere. (40 CFR or treatment system waste that
be stored 264.101 in a container ILe., any 40 CFR 264.173 might be containerized and stored
. Closed during storage (except to edd portable device in which a material on site prior to treatmant or linal
or remove waste) is stored, transported, disposed 01. disposal. Groundwater or soil
or handledl. containing a listed waste must be
managed es il it were e hazardolls
waste so long as it contains tha
listad wasta.
Inspect containar storaga araas waekly 40 CFR 264.174 B,C, D
lor deterioration.
Place containers on slopad, crack-free 40 CFR 264.175 B,C. D
base, end protect from contect with
accumulated liquid. Provide conteinment
system with a cepacity 01 10 percent 01
the volume 01 containers 01 free liquids.
Remove spilled or leaked waste in a
timely menner to prevent overflow 01 the
containment system.
KN/NEW.A-61t 2.t6.92/F
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Table A-G. Action-Specific Applicable or Relevant and Appropriate Requirements
and Other Criteria to be Considered
(Page 2 of 51
Action Requirementls) Prerequisitelsl Citation Comments A8 RARb TBCe
Containar Keep containars of ignitable or reactive 40 CFR 264.176 B, C,
Storage waste at least 50 feet from the facility's D
(On-Site) property line.
(Continued) .. . -
Keep incompatible materials separate. 40 CFR 264.177 B, C,
Separate incompatibla materials storad near D
each othar by a dika or other barrier.
At closure, remove all hazardous waste and 40 CFR 264.178 B, C,
residues from the containment system, and D
dacontaminata or ramove all containars,
linars.
Storaga of bannad wastas must be in 40 CFR 268.50 B, C,
accordance with 40 CFR 268. Whan such D
storage occurs beyond one year, the
owner/operator bears the burdan of proving
that such storage is solely for the purpose
of accumulating sufficient quantities to
allow for proper recovery, treetment, and
disposel.
Injection Aquifer Protection Requirements from The substantiva C, D
ADEQ requirements of ARS
49-243.
ADEQ Water Quality Standards identifying Injection of groundwater ARS 49-224 C, D
aquifers as drinking water aquifers
Groundwater Any nonwaste material (e.g., groundwater Nonwaste material containing listed RCRA "contained in" e, C,
Well or solll that contains a listed hazardous hazardous waste principle D
Development, waste must ba managad as if it wera a
Testing, and hazardous waste.
Sampling
Surfaca Watar Pravant run-on and control and collact run- RCRA hazardous waste treated, stored, or 40 CF~ 264.273 (c) e, C,
Control off from a 24-hour 25-year storm (land disposed after the affective date of the (d) D
treatment facility). requirements.
KN/NEW.A-6/12-17-92/F
-------
Table A-G. Action-Specific Applicable or Relevant and Appropriate Requirements
and Other Criteria to be Considered
(Page 3 of 5)
Action Requirement(s) Prerequisite(s) Citation Comments AO RARb raCe
All Off-Site The off-site shipment of hezerdous weste Genereting site to ship weste off-site. 40 CFR 262, 40 CFR C, D B
Shipment requires that all RCRA and DOT 263,49 CFR 171
Requirements raquirements for manifesting and shipping through 179
for Hazardous papars as naedad, marking, labeling,
Waste Per placarding, and spacial raquiramants based
RCRA and DOT or type of carriaga (La., rail, aircraft, public
Regulations Will highway, etc.) be met.
Be Met by the
OU-2 Site
IGenerator) and
Transporter
Storm Water Operations as defined in the regulations Discharge of.storm water from industrial 40 CFR 122 B, C,
Permitting that discharge storm water from its facility facilities and large construction sites D
must perform sampling, submit a permit Igreater than five ecres in araal.
epplication, end comply with ell permit
requirements, water quality stendards, end
effluent limitations set by Bast Achiavable
Tachnology (BATI.
Incineration Analyze the waste feed. RCRA hazardous waste. 40 CFR 264.341 D
Disposa of all hazardous waste and 40 CFR 264.351 D
residues, including ash, scrubber water,
and scrubber sludge.
No further raquirements apply to 40 CFR 264.340 D
incinerators thet only burn wastes that are
listed as hazardous solely by virtue of
combination with other wastes, and if tho
waste analysis demonstrates that no
Appendix VII constituent is present thet
might reasonably be expected to be
present.
On-Site Controlling emissions from nonpoint Emissions from nonpoint sources AAC RI8-2-401, B, C,
Construction sources 402, 404, 405, 406, D
and 407, end 410
Remedietion
Controlling emissions from mobile sources Emissions from mobile sources AAC R 18-2-601 B, C,
through 605 D
KN/NEW.A-6/12-16-92/F
-------
Table A-G. Action-Specific Applicable or Relevant and Appropriate Requirements
and Other Criteria to be Considered
(page 4 of 51
Action Requirementls) Prerequisite Is) Citation Comments A" RARb THC.
Closure with 30-year post-closure care end groundwater Applicable to land disposal of hazardous 40 CFR 264.310 B
Waste in Piece monitoring. waste. Applicable to RCRA hazardous
waste (listed or characteristicl pia cad at
sita after the effectiva date of tha
requirements, or placed into another unit.
Not applicable to material treated, stored,
or disposed only before the effective dete
01 the requirements, or if treated in-situ or
consolidated within area of
contamination.
Closure with No General performance standard requires Applicable to land-based unit containing 40 CFR 264.111 B, C,
Post-Closure elimination of need for furthar maintenance hazardous waste. Applicabla to RCRA D
Care le.g., and control; elimination 'of post-closure hazardous waste (listed or characteristicl
Clean Closure) escape of hazardous waste, hazardous placad at site altar the effective dete of
constituents, leachate, contaminated run- the requiremants, or placed into another
off, or hazardous waste decomposition unit. Not applicable to material treatad,
products. stored, or disposad only before the
effective date of the requirements, of if
treated in-situ, or consolidated within aree
of contamination. Designad for claanup
thlt' .,:1 not require long..term
menugement. Designed for cleanup to
health-based standards.
Disposal or decontamination of equipment, May apply to surface impoundments and 40 CFR 264.111 ! B, C,
structures, and soils. container or tank liners and hazardous 40 CFR 264.178 D
waste residues, and to contaminated soil, 40 CFR 264.197
Removal or decontamination of all waste including soil from dredging or soil 40 CFR 264.288 (01 ,
rasidues, contaminatad containment disturbed in the course of drilling or (11 and
system components le.g., liners, dikes), excRvation, and returned to land. 40 CFR 264.258 I
contaminated subsoils, and structures and
equipment contaminated with wasta and
leachata, and management of them as
hezardous waste.
Meet health-based levels at unit. 40 CFR 244.111 C, D B
KN/NEW.A-6112-16-92/F
-------
Table A-G. Action-Specific Applicable or Relevant and Appropriate Requirements
and Other Criteria to be Considered
(Page 5 of 5)
Action Requlrementls) Prerequisitels) Citation Comments AO RARb raCe
Treetment Design end operating stendards for all Treatmant of hazardous wastas in units 40 CFR 264 (Subpart The substantive portions C,D
hazardous waste treatmant units including and regulated elsewhere under RCRA XI, 40 CFR 264.273, of these requirements will
miscelleneous units (long term retrievable le.g., air strippersl. 40 CFR 264.343- be relevant and
storage, tharmal treatment other then 345, 40 CFR 265 appropriate to the
incineretion, open burning, open (Subpart PI construction, oparation,
datonation, chemical physical, and maintanance, and closure
biological treetment units using other than of any miscelleneous
tanks, surface impoundments, or land treatmant unit la
treatment unitsl require new miscellanaous traatment unit that is not
units to satisfy environmental performance elsewhere ragulated)
standards by protaction of groundwatar, constructed on tha OU-2
surfaca water, and air quality, and by site for treatment and/or
limiting surface and subsurfaca migration. disposal of hazardous sita
wastes.
Ragulations for land-based corrective Land-besed remedial action 40 CFR Subpart S The substantive portions B. C,
actions of RCRA facilitias. (Ravisedl of these raquirements are D
ralavant and appropriate
to tha treatment prior to
disposel of any OU-2 site
wastes in concentrations
that meke the site wastes
sufficiently similar to tho
regulatod wastes. Tha
requirements spacify
lavels of treatmant that
must ba attainad prior to
land disposal.
Traatment of wastes subject to ban on land Treatment of LDR waste 40 CFR 268 (Subpart The substantive portions B, C,
disposal must attain levels achiavable bV D), 40 CFR 268.10, of thasa requirements are D
bast demonstrated evallable treatment 268.11. 268.12 to be considered in the
technologies IBDA TI for each hazardous disposal of any OU-2 sita
constituant In each listad wasta. wastas that can ba
desired as restricted
hazardous westes.
. Applicable Raquirements for Alternatives B, C, or D as noted.
. Relevant and Appropriate Requirements for Alternetives B, C, or D as noted.
e Criteria To Be Considered for Alternetives ,B, C, or D as noted.
KN/NEW.A-6/t 2-16-92/F
-------
"-
,
KN/NEW.COV/12-1S-92IF
Appendix B
Cos:~ Estimat:~s for Selected Alternative
-------
8-1. AIR STRIPPING COST ESTIMATE
VERTICAL WELLS WITH FUME INCINERATION
Capital Costs
Williams AFB
Project-409735.3023.002
KT - wiairsv1 - 07/01/92
COST COMPONENT
DIRECT CAPITAl COSTS
1 . Site Preparation
2.
Extraction Wells
3. Injection Wells
4. Extraction Well pumps
5. Monitoring Wells
6. Air System for Well Pumps
7. Transfer Systems
s.
OiVwater Separator
9.
Air stripping system
10. Fume incineration system
11 . Instrumentation
TOTAl DIRECT COST (TOC)
INDIRECT CAPITAL COSTS
1. Engineering and Design
2.
License. permit, legal fees
3.
Start-up
4.
Contingency
TOTAL INSTALLED COST
( +50% , -30% )
DESCRIPTION
2.2 Acres
16 Recovery wells. sa Id 55 casing,
240 feet depth/well
4 Injection wells. sa Id 55 casing,
240 feet depth/well
16 Extraction well pumps, including
piping and controls
2 Monitoring wells, 260 feet depth/well
Compressor system
Transfer pumps and storage tanks for
untreated and treated water
Rated for 60 gallons/min.
Skid mounted system, 2 air stripping
columns, 2.5' dia, 1S' packing! colum
1.2 million BTU/hour, 1000 cfm, 1600 F
Central control and monitoring system
12 % TOC
2 % TDC
5 % TDC
15 % TOC
.
COST
($)
32,800
768,000
192,000
112,000
60,600
120,000
283,100
13,000
91,300
144,000
100,000
1,916,800
230,016
38,336
95,840
287,520
2,568,512
-------
B-2. AIR STRIPPING COST ESTIMATE
VERTICAL WELLS WITH FUME INCINERATION
Annual Operating and Maintenance Costs
Williams AFB
Project - 409735.30.23.002
KT - wiairsv1 - 07/01/92
UNIT
COST UNITS 1 COST
COST COMPONENT ($) UNIT QUANT!TY PERIOD ($/year)
1. Operating labor 50 hour (hr) 20 hrlweek 52,000
2. Maintenance (1% TOC) 19,168
3. Materials
NA
4. Utilities
Electrical power 0.08 Kwhr 2190 Kwhr/day 63,948
Fuel 5 million BTU 33.6 million BTU 61,320
per day
5. isposal (2.)
6. Purchased services
Monitoring - Effluent 600 sample (5) 2 s Imonth 14,400
- Wells (b) 73,300
7. Administration
Data evaluation Ireporting 70 hr 16 hr/month 13,440
TOTAL 297,576
8. Insurance, permits, taxes 4% operating 11,903
9. Rehabilitation costs (c) 30,000
10. Contingency 15% operating 44,636
11. Periodic site review (d) 20,000
TOTAL ANNUAL OPERATING COST 404,115
( +50% , -30% )
a. Cost for shipping recovered free phase hydrocarbons to reclaimer or Air Force user is
considered covered by fuel value. .
b. From groundwater, no action GW-1.
c. Replacement of mechanical components every 10 years.
d. Every 5 years; cost shown is allocation for one year.
NA - not applicable
-------
B-3. AIR STRIPPING COST ESTIMATE
VERTICAL WELLS WITH VAPOR-PHASE CARBON ADSORPTION
Capital Costs
Williams AFB
Project-409735.30.23.002
KT - wiairsv2 - 07/01/92
COST
COST COMPONENT DESCRIPTION ($)
DIRECT CAPITAL COSTS
1. Site Preparation 2.2 Acres 32,800
2. Extraction Wells 16 Recovery wells. 8" Id ss casing. 768.000
240 feet depth/well
3. Injection Wells 4 Injection wells, 8" Id ss casing, 192,000
240 feet depth/well
4. Extraction Well pumps 16 Extraction well pumps, including 112,000
piping and controls
5. Monitoring Wells 2 Monitoring wells, 260 feet depth/well 60.600
6. Air System for Well Pumps Compressor system 120,000
7. Transfer Systems Transfer pumps and storage tanks for 283,100
untreated and treated water
8. OiVwater Separator Rated for 60 gallons/min. 13,000
9. Air stripping system Skid mounted system, 2 air stripping 91,300
columns, 2.5' dia, 18' packing! colum
10. Vapor-Phase Carbon Skid mounted system, 78,000
Adsorption System 8000 Ibs carbon capacity
11. Instrumentation Central control and monitoring system 100,000
TOTAL DIRECT COST (TDC) 1,850,800
INDIRECT CAPITAL COSTS
1. Engineering and Design 12 % TDC 222.096
2. License, permit. legal fees 2% TDC 37.016
3. Start-up 5% TDC 92.540
4. Continaencv 15 % TDC 277.620
TOTAL INSTALLED COST 2,480,072
( +50% , -30% )
-------
B-4. AIR STRIPPING COST ESTIMATE
VERTICAL WELLS WITH VAPOR-PHASE CARBON ADSORPTION
Annual Operating and Maintenance Costs
Williams AFB
Project - 409735.30.23.002
KT - wiairsv2 - 07101/92
UNIT
COST UNITS 1 COST
COST COMPONENT ($) UNIT QUANTITY PERIOD ($/year)
1. Operating labor 50 hour (hr) 20 hrlweek 52,000
2. Maintenance (1% TOC) 18,508
3. Materials
Carbon (a) 2.4 pound (Ib) 300 Iblday 262,800
-
4. Utilities
Electrical power 0.08 Kwhr 2190 Kwhr/day 63,948
5. Disposal (b)
6. Purchased services
Monitoring - Effluent 600 sample (s) 2 s Imonth 14,400
- Wells (c) 73,300
7. Administration
Data evaluation Ireporting 70 hr 16 hr/month 13,440
TOTAL 498,396
8. Insurance, permits, taxes 4% operating 19,936
9. Rehabilitation costs (d) 30,000
10. Contingency 15% operating 74,759
11. Periodic site review (e) 20,000
TOTAL ANNUAL OPERATING COST 643,091
( +50% , -30% )
a. Cost includes carbon purchase, shipping, and regeneration of spent carbon by supplier.
b. Cost for shipping recovered free phase hydrocarbons to reclaimer or Air Force user is
considered covered by fuel value.
c. From groundwater, no action GW-1.
d. Replacement of mechanical components every 10 years.
e. Every 5 years; cost shown is allocation for one year.
NA - not applicable
-------
8-5. AIR STRIPPING COST ESTIMATE
HORIZONTAL WELLS WITH FUME INCINERATION
Capital Costs
Williams AFB
Project-409735.30.23.002
KT - wiairsh1 - 07/01/92
COST
COST COMPONENT DESCRIPTION ($)
DIRECT CAPITAL COSTS
1. Site Preparation 2.2 Acres 32,800
2. Extraction Wells 2 Recovery wells, 6" SS riser, 1,700,000
235 feet depth/well, 500 feet of 6" SS Screen
3. Injection Wells 4 Injection wells, 4" Id SS casing, 121,200
200 feet depth/well, 100 feet of 4" SS Screen
4. Extraction Well pumps 3 Extraction well pumps, including 454,000
piping and controls
5. Monitoring Wells 3 Monitoring wells, 4.5" sch 80 pvc casing, 90,900
260 feet depth/well, 40 feet of 4" SS Screen
6. Transfer Systems Transfer pumps and storage tanks for 283,100
untreated and treated water
7. Oil 1 water separator Rated for 60 gallons/min. 13,000
8. Air stripping system Skid mounted system, 2 air stripping 91,300
columns, 2.5' dia, 18' packing! colum
9. Fume incineration system 1.2 million BTU/hour, 1000 cfm, 1600 F 144,000
10. Instrumentation Central control and monitoring system 100,000
TOTAL DIRECT COST (TDC) 3,030,300
INDIRECT CAPITAL COSTS
1. Engineering and Design 12 % TDC 363,636
2. License, permit, legal fees 2% TDC 60,606
3. Start-up 5% TDC 151,515
4. ContinQencv 15 % TDC 454,545
TOTAL INSTALLED COST 4,060,602
( +50% , -30% )
-------
8-6. AIR STRIPPING COST ESTIMATE
HORIZONTAL WELLS WITH FUME INCINERATION
Annual Operating and Maintenance Costs
Williams AFB
Project - 409735.30.23.002
KT - wiairsh1 - 07/01/92
Uk"
COS';- UNITS 1 COST
COST COMPONENT ($) UNIT QUANTITY PERIOD ($/year)
1. Operating tabor 50 hour (hr) 20 hr/week 52,000
2. Maintenance (1% roC) 30,303
3. Materials
NA
4. Utilities
Electrical power 0.08 Kwhr 931 Kwhr/day 27,185
Fuel 5 million BTU 33.6 million BTU 61,320
per day
5. Disposal (a)
6. Purchased services
Monitoring - Effluent 600 sample (s) 2 s Imonth 14,400
- Wells (b) 74,900
7. Adminis,;'ation
Data evaluation Ireporting 70 hr 16 hr/month 13,440
TOTAL 273,548
8. Insurance, permits, taxes 4% operating 10,942
9. Rehabilitation costs (c) 40,000
10. Contingency 15% operating 41,032
11. Periodic site review (d) 20,000
-
TOTAL ANNUAL OPERATING COST 385,522
( +50% , -30% )
a. Cost for shipping recovered free phase hydrocarbons to reclaimer or Air Force user is
considered covered by fuel value.
b. From groundwater, no action GW-1, and one additional monitoring well.
c. Replacement of well pumps every 4 years, and 10 years for other mechanical components.
d. Every 5 years; cost shown is allocation for one year.
NA - not applicable
-------
B-7. AIR STRIPPING COST ESTIMATE
HORIZONTAL WELLS WITH VAPOR-PHASE CARBON ADSORPTION
Capital Costs
Williams AFB
Project-409735.30.23.002
KT - wiairsh2 - 07/01/92
COST
COST COMPONENT DESCRIPTION ($)
DIRECT CAPITAL COSTS
1. Site Preparation 2.2 Acres 32,800
2. Extraction Wells 2 Recovery wells, 6" SS riser, 1,700,000
235 feet depth/well, 500 feet of 6" SS Screen
3. Injection Wells 4 Injection wells, 4" Id SS casing, 121 ,200
200 feet depth/well, 100 feet of 4" SS Screen
4. Extraction Well pumps 3 Extraction well pumps, including 454,000
piping and controls
5. Monitoring Wells 3 Monitoring wells, 4.5" sch 80 pvc casing, 90,900
260 feet depth/well, 40 feet of 4" SS Screen
6. Transfer Systems Transfer pumps and storage tanks for 283,100
untreated and treated water
7. OiVwater separator Rated for 60 gallons/min. 13,000
8. Air stripping system Skid mounted system, 2 air stripping 91,300
columns, 2.5' dia, 18' packing! colum
9. Vapor-Phase Carbon Skid mounted system, 78,000
Adsorption System 8000 Ibs carbon capacity
10. Instrumentation Central control and monitoring system 100,000
TOTAL DIRECT COST (TDC) 2,964,300
INDIRECT CAPITAL COSTS
1. Engineering and Design 12 % TOC 355,716
2. Ucense, permit, legal fees 2% TOC 59,286
3. Start-up 5% TOC 148,215
4. Contingency 15 % TOC 444,645
TOTAL INSTALLED COST 3,972,162
( +50% . -30% )
-------
B-8. AIR STRIPPING COST ESTIMATE
HORIZONTAL WELLS WITH VAPOR-PHASE CARBON ADSORPTION
Annual Operating and Maintenance Costs
Williams AFB
Project - 409735.30.23.002
KT - wiairsh2 - 07/01/92
UNIT
COST UNITS 1 COST
COST COMPONENT ($) UNIT QUANTITY PERIOD ($/year)
1. Operating labor 50 hour (hr) 20 hr/week 52,000
2. Maintenance (1 % TOC) 29,643
3. Materials 2.4 pounds (Ib) 300 Ib/day 262,800
Carbon (a)
NA
4. Utilities
Electrical power 0.08 Kwhr 931 Kwhr/day 27,185
5. Disposal (b)
6. Purchased services
Monitoring - Effluent 600 sample (s) 2 s Imonth 14,400
- Wells (c) 74,900
7. Administration
Data evaluation Ireporting 70 hr 16 hr/month 13,440
TOTAL 474,368
8. Insurance, permits, taxes 4% operating 18,975
9. Rehabilitation costs (d) 40,000
10. Contingency 15% operating 71,155
11. Periodic site review (e) 20,000
TOTAL ANNUAL OPERATING COST 624,498
( +50% , -30% )
a. Cost includes carbon purchase, shipping, and regeneration of spent carbon by supplier.
b. Cost for shipping recovered free phase hydrocarbons to reclaimer or Air Force user is
considered covered by fuel value. .
c. From groundwater, no action GW-1, and one additional monitoring well.
d. Replacement of well pumps every 4 years and 10 years for other mechanical components.
e. Every 5 years; cost shown is allocation for one year.
NA - not applicable
-------
B-9. SVE WITH IN SITU BIOREMEDIATION COST ESTIMATE
FUME INCINERATION
Capital Costs
Williams AFB
Project-409735.30.23.002
KT - wisvefi - 07/01/92
COST
COST COMPONENT DESCRIPTION ($)
DIRECT CAPITAL COSTS
1. Site Preparation 2.2 Acres 32,800
2. Extraction Wells 64 Extraction wells, 4" diameter 128,000
25 feet depth/well
3. Passive vent wells 32 Vent wells, 4" diameter 48,000
25 feet depth/well
4. Nested pieziometers 51 pieziometers 102,000
5. Plastic covers 50,000 square feet (ft2) at 0.5 $/(ft2) 25,000
6. Piping system 4" PVC, schedule 80 34,000
7. Vacuum system 19 Hp, 320 cubic foot per minute (cfm) 55,800
8. Fume Incineration Skid mounted system, rated 500 cfm air 106,400
9. Nutrient system Ammonia addition 15,000
10. Treatability testing Bench-scale biotreatment 65,000
11. Instrumentation Central control and monitoring system 100,000
TOTAL DIRECT COST (TDC) 712,000
INDIRECT CAPITAL COSTS
1. Engineering and Design 15% TDC 106,800
2. License, permit, legal fees 2% TOC 14,240
3. Start-up 5% TDC 35,600
4. Contingency 15 % TOC 106,800
TOTAL INSTALLED COST 975,440
( +50%, -30% )
-------
B-10. SVE WITH IN SITU BIOREMEDIATION COS.; ::::STlMATE
FUME INCINERATION
Annual Operating and Maintenance Costs
FIRST YEAR
Williams AFB
Project-409735.3023.002
KT. wisvefi . 07/01/92
_.~~IT COST
COST UNITS 1 ($/year)
COST COMPONENT ($) UNIT QUANTITY PERIOD (a)
1. Operating labor 50 hour (hr) 32 hr/sampling 24,000
event
2. Maintenance (2% TOC) 14,240
3. Materials (nutrient) (b) 0.9 pound (Ib) 135 Ib/day 22,174
4. Utilities
Electrical power 0.08 Kwhr 340 Kwhr/day 9,928
Fuel 5 million STU 11 million STU 20,075
per day
5. Disposal NA
6. Purchased services
Vapor monitoring 550 sample (s) 6 slsampling 49,500
Soil monitoring (c) event 18,000
Sio monitoring 19,200
7. Administration
Data evaluation/reporting 70 hr 32 hr/sampling 23,520
(For SVE & 6 months of Sio) event
TOTAL 200,637
8. Insurance, permits, taxes 4% operating 8,025
9. Rehabilitation costs NA
10. Contingency 15% operating 30,096
11. Periodic site review NA
TOTAL ANNUAL OPERATING COST 238,758
( +50%, -30% )
a. 15 sampling eventslfirst year
b. Sioremediation will start from 6 months
c. From soil no action S-1
NA . not applicable
-------
B-11. SVE WITH IN SITU BIOREMEDIATION COST ESTIMATE
FUME INCINERATION
Annual Operating and Maintenance Costs
SECOND AND THIRD YEAR
Williams AFS
Project-409735.3023.002
KT - wisvefi - 07/01/92
UNIT COST
COST UNITS/ ($/year)
COST COMPONENT ($) UNIT QUANTITY PERIOD (a)
1. Operating labor 50 hour (hr) 32 hr/sampling 19,200
event
2. Maintenance (2% TOC) 14,240
3. Materials (nutrient) 0.9 pound (Ib) 135 Ib/day 44,348
4. Utilities
Electrical power (b) 0.08 Kwhr 170 Kwhr/day 4,964
Fuel (b) 5 million STU 5.5 million STU 10,038
per day
5. Disposal NA
6. Purchased services
Vapor monitoring 550 sample (s) 6 sfsampling 39,600
Soil monitoring (c) event. 18,000
Sio monitoring 19,200
7. Administration
Data evaluation/reporting 70 hr 32 hr/sampling 26,880
(for SVE and Sio) event
TOTAL 196,469
8. Insurance, permits, taxes 4% operating 7,859
9. Rehabilitation costs NA
10. Contingency 15% operating 29,4!0
11. Periodic site review NA
TOTAL ANNUAL OPERATING COST 233,798
( +50%, -30% )
a. 12 sampling eventsfsecond year.
b. All vacuum pumps would be operated at 1/2 capacity for bioremediation,
thereby reducing power and fuel consumption.
c. From soil no action S-1.
-------
B-12. SVE WITH IN SITU BIOREMEDIATION :'.ST ESTIMATE
VAPOR-PHASE CARBON ADSORF -, ,)N
Capital Costs
Williams AFB
Project-409735.30.23.002
KT - wisvevp - 07/01/92
COST
COST COMPONENT DESCRIPTION ($)
DIRECT CAPITAL COSTS
1. Site Preparation 22 Acres 32.800
2. Extraction Wells 64 Extraction wells, 4" diameter 128.000
25 feet depth/well
3. Passive vent wells 32 Vent wells. 4" diameter 48.000
25 feet depth/well
4. Nested pieziometers 51 pieziometers 102.000
5. Plastic covers 50,000 square feet (ft2) at 0.5 $I(ft2) 25.000
6. Piping system 4" PVC, schedule 80 34.000
7. Vacuum system 19 Hp, 320 cubic foot per minute (cfm) 55,800
8. Vapor-phase carbon Four skid mounted systems. each has 408,000
adsorption ~:ystem 11,000 Ib carbon capacity
9. Nutrient sys:em Ammonia ac--:~;~' 15.000
10. Treatability testing Bench-scale biotreatment 65.000
11. Instrumentation Central control and monitoring system 100.000
TOTAL DIRECT COST (TDC) 1.013,600
INDIRECT CAPITAL COSTS
1. Engineering and Design 15% TDC 152,040
2. License. permit. legal fees 2% TDC 20,272
3. Start-up 5% TOC 50,680
4. Contingency 15 % TDC 152,040
TOTAL INSTALLED COST 1,388.632
( +50%. -30% )
-------
B-13. SVE WITH IN SITU BIOREMEDIATION COST ESTIMATE
VAPOR-PHASE CARBON ADSORPTION
Annual Operating and Maintenance Costs
FIRST YEAR
Williams AFB
Project-409735.30.43.002
KT - wisvevp - 07/01/92
UNIT COST
COST UNITS 1 ($/year)
COST COMPONENT ($) UNIT QUANTITY PERIOD (a)
1. Operating labor 50 hour (hr) 32 hrlsampling 24,000
event
2. Maintenance (2% TOC) 20,272
Carbon maintenance 30,000
3. Materials (nutrient) (b) 0~9 pound (Ib) 135 Ib/day 22,174
Carbon (c) 2.4 2.47 M Iblyear 5.928,000
4. Utilities
Electrical power 0.08 Kwhr 340 Kwhr/day 9,928
5. Disposal NA
6. Purchased services
Vapor monitoring 550 sample (s) 6 slsampling 49,500
Soil monitoring (c) event 18,000
Sio monitoring (d) 19,200
7. Administration
Data evaluation/reporting 70 hr 32 hrlsampling 23,520
(For SVE & 6 months of Sio) event
TOTAL 6,144,594
8. Insurance, permits, taxes 4% operating 245,784
9. Rehabilitation costs NA
10. Contingency 15% operating 921,689
11. Periodic site review NA
TOTAL ANNUAL OPERATING COST 7,312,067
( +50%, -30% )
a. 15 sampling events/first year
b. Sioremediation will start from 6 months
c. Cost includes carbon purchase, shipping, and regeneration of spent carbon by supplier.
d. From soil no action S-1
NA - not applicable
-------
B-14. SVE WITH IN SITU BIOREMEDIATION COST ESTIMATE
VAPOR-PHASE CARBON ADSORPTION
Annual Operating and Maintenance COStS
SECOND YEAR
Williams AFB
Project-409735.30.23.oo2
KT - wisvevp - 07/01/92
UNIT COST
COST UNITSI ($/year)
COST COMPONENT ($) UNIT QUANTiTY PERIOD (a)
1. Operatir;~: labor 50 hour (hr) 32 hrlsampling 19,200
event
2. Maintenance (2% TOC) 20,272
Carbon maintenance 6,400
3. Materials (nutrient) 0.9 pound (Ib) 135 Iblday 44,348
Carbon (b) 2.4 Ib 559,000 Ib/y: 3.r 1,341,600
4. Utilities
Electrical power (c) 0.08 Kwhr 170 Kwhr/day 4,964
5. Disposal NA
6. Purchased services
Vapor monitoring 550 sample (s) 6 s/sampling 39,600
Soil monitoring (c) event 18,000
Bio monitoring (d) ; 19,2~J
7. Administration
:
Data evaluation/reporting 70 hr 32 hrlsampling 26,880
(for SVE and Bio) event
TOTAL 1,540,464
8. Insurance, permits, taxes 4% operating 61,619
9. Rehabilitation costs NA
10. Contingency 15% operating 231,07.0
11. Periodic site review NA
TOTAL ANNUAL OPERATING COST 1,833,152
( +50%, -30% )
a. 12 sampling events/second year.
b. Cost includes carbon purchase, shipping, and regeneration of spent carbon by supplier.
c. All vacuum pumps would be operated at 1/2 capacity for bioremediation,
thereby reducing power and fuel consumption.
d. From soil no action S-1.
-------
8-15. SVE WITH IN SITU 810REMEDIATION COST ESTIMATE
VAPOR-PHASE CARBON ADSORPTION
Annual Operating and Maintenance Costs
THIRD YEAR
Williams AFB
Project-409735.30.23.002
KT - wisvevp - 07/01/92
UNIT COST
COST UNITS/ ($/year)
COST COMPONENT ($) UNIT QUANTITY PERIOD (a)
1. Operating labor 50 hour (hr) 32 hr/sampling 19,200
event
2. Maintenance (2% TOC) 20,272
Carbon maintenance 4,800
3. Materials (nutrient) 0.9 pound (Ib) 135 Ib/day 44,348
Carbon (b) 2.4 Ib 449,700 Ib/year 1,079,300
4. Utilities
Electrical power (b) 0.08 Kwhr 170 Kwhr/day 4,964
Fuel (b) 5 million BTU 5.5 million BTU 10,038
per day
5. Disposal NA
6. Purchased services
Vapor monitoring 550 sample (s) 6 slsampling 39,600
Soil monitoring (c) event 18,000
Bio monitoring 19,200 .
7. Administration
Data evaluation/reporting 70 hr 32 hr/sampling 26,880
(for SVE and Bio) event
TOTAL 1,286,601
8. Insurance, permits, taxes 4% operating 51,464
9. Rehabilitation costs NA
10. Contingency 15% operating 192,990
11. Periodic site review NA
TOTAL ANNUAL OPERATING COST 1,531,055
( +50%, .30% )
a. 12 sampling eventslthird year.
b. Cost includes carbon purchase, shipping, and regeneration of spent carbon by supplier.
c. All vacuum pumps would be operated at 1/2 capacity for bioremediation,
thereby reducing power and fuel consumption.
d. From soil no action S-1.
-------
Alternative C
Letters Recommending Methods and Products
KNfNEW.COV 112-1S-92/F
-------
PROBIOTIC~
...0...0.0.00.0000.000000
.....0..0.0..000.0000.000
5 0
L
UTI
o N
5
June 22, 1992
Mr. Willard S. Carter
Project Manager
International Technology
312 Directors Drive
Knoxville, TN 37923
Corporation
RE:
Williams APB OU-2 site remediation
Dear Mr. Carter:
I 'Was pleased to meet you at
Arizona June 1£, 1992. I feel
In Situ Bioremediation is
alternative at this location.
the public meeting in Mesa,
that Alternative C utilizing
certainly the preferred
Our company has developed bioremediation products 'Which
enhance biological degradation of contaminants. This
probiotic technology 'Was developed first for agriculture
beginning in 1973 and has been adapted for bioremediation of
contaminants in a 'Wide range of applications.
Our probiotic products contain complexing agents, organic
acids, buffers, biological systems and nutrients 'Which
enhance biological degradation. These biological systems
adapt to the contaminant substrate reducing the compound
economically and expeditiously. Our probiotic products are
concentrated, contain no toxic materials, and are easy to
use.
I am enclosing some information to familiarize you 'With our
company and products. We have contractors in the field 'Who
have developed soil vapor extraction procedures -using our
probiotic products 'Which are very effective and economical.
I 'Will send copies of these reports if you 'Would like to
revie'W them.
3 N. ROOSEVELT AVE.' CHANDLER. AZ 85226.602-961-1220. FAX 602-961.3501
-------
-2-
We would like to show you how our
your Al ternati ve C plan at your
will contact you after you have
enclosed information to determine
enhance this project.
Sincerely,
~7J{~.£-
Ken Martin
Director
?chnology will fit into
t~:'liest convenience. I
- chance to review the
how our technology can
CC: Maureen Levitz, David R. Annis, Bill Pehlivanian, Mike
Van Fleteren, William Lopp
-------
rn INTERNATIONAL
TECHNOLOGY
CORPORATION
July 9, 1992
Mr. Ken Martin, Director
Probiotic Solutions
3 N. Roosevelt Avenue
Chandler, AZ 85226
Reference:
Subject:
Your Letter of June 22, 1992
Williams AFB, Project No. 409735, In Situ Bioremediation
Dear Mr. Martin:
We appreciate your information concerning Probiotics and its products. We are reviewing its
application to the soil vapor extraction process at Williams AFB but any final determination will
have to await initiation and funding of the remedial design phase for Operable Unit 2.
We appreciate your interest in providing a cost-effective solution to cleanup of Operable Unit 2
at the Williams AFB site. Please contact me if there are other questions. Your interest and
address are being retained.
Sincerely,
I I
/1 J
" /
~S~;;--
Senior Contracts Administrator
Ibf
cc:
Maureen Leavitt
David Annis
Bill Pahlivanian
Mike Van Fleteren
William Lapp
Will Carter
WCOOI.hIlP8J< Z
Regional Ottice
312 Directors Drive -Knoxville. Tennessee 37923.615-690-3211
-------
Mesa, Arizona
June 25, 1992
International Technology Corporation
312 Directors Drive
Knoxville, Tennessee 37923
Williard S. "Will" Carter
Project Manager
Teresa Kovalcson
Chemist
Re:
Williams Air Force Base Clean-Up
I am writing about the clean-up proposal I talked to you
about, recently in Mesa, Arizona. I do want this letter
to become a part of the official r.port.
OU-2 ALTERNATIVE-STEVEN A. TALLEY:
SOIL WASHING
This alternative would involve soil boring 0 to 2S feet
in order to provide a reasonable and equitable
distribution of the soil washing cleaning compound mixed
with water. A total of 121,000 cubic yards would be
processed by contacting the contaminated soil with the
washing fluid. ITCreports only 67,000 cubic yards
would be excavated and washed instead of the 121,000
yards I claim needs washIng-
The washing fluid, containing water, i8 a solvent type:
The solvent type cleaner utilizes a solvent extracted
from food products; in addition, various detergents
(chemicals that act as soaps) are added. Safe
surfactants are also used to reduce the surface tension
to allow the ALKALI products to work (clean) more
effectively.
The above described washing fluid
proprIetary. The material safety
prepared and issued in accordance
1910.1200.
product is
data sheets have been
with (lAW) CPR 29
The washing step is to be done in three stages. Each
stage of the washing will either emulsify the
contaminant and convert it into soap or protei~ for the
s011 bacteria to eat or else 1t will chelate or
encapsulate the contaminant and convert it from toxic to
non-toxic particles, thus eliminating the need to remove
any toxic residuals.
-------
/
(
i
As a matter of inforaation, the founder, inventor and
chemist of HDI was at one time an inspector (POL) at
Williams Field for 5 1/2 years. He knew first hand of
the draining of the JP-4 tanks and Aviation gasoline
directly on the ground. I have permission to use his
name - George Aboud, Sr. He knows exactly what was put
into the ground and, using his patented products, I can
change the contaminants into non-toxic particles and
protein for the soil bacteria food chain.
COST
The estimated present worth cost of the OU-2 ALTERNATIVE
- STEVEN A. TALLEY: SOIL WASHING 1s $12.85 million with
the principal cost being equipment charges, operating
labor, and the solvent costs. According to my
calculations, the projected quantity of surface and
subsurface soil to be treated is larger than what the
ITC proposes - 121,000 cubic yards versus your 67,000
cubic yards. My proposal 1s about half the cost for
almost twice the amount of soil.
I would be very interested 1n knowing the results of the
tests I propose that you complete. I know we both want
the most effective clean-up for the minimum cost.
If you have any questions regarding
please call me at (602) 962-8282.
~Ji;:-Ci7t{{{ /
Steven A. Talley ~
2043 E. 7th Ave
Mesa, Arizona 85204
the above proposal,
Enclosures
cc:
Senator John Mcca1n
Senator Dennis DeConcini
Capt. Mary Fe1tault
Mr. David R. Annis
Mr. Wl111am B. Lopp
Capt. Sally Watson
Mr. Hlke Van Fleteran
Col. T1m Peppe
Hr. B111 Pehllvanlan
-------
I -
I
rn INTERNATIONAL
TECHNOLOGY
CORPORATION
July 9, 1992
Mr. Stephen A. Tally
2043 East 7th Avenue
Mesa, AZ 85204
Subject:
Your Letter of June 25, 1992
Williams AFB, Project 409735, Soil Washing
Dear Mr. Tally:
We appreciate your proposal for use of a heavy duty industrial degreaser (HDI) in washing the
soil at Williams AFB Operable Unit 2. Currently we are examining the cost comparison. A
determination of the effectiveness of your product will have to await initiation and funding of
the remedial design phase for Williams AFB.
Please notify me if you have any further questions. Your interest and address are being reta~;::;;d.
Sincerely,
~(
, "-- '--y---
Greg..8ergent
Senior Contracts Administrator
/bf
cc:
Senator John McCain
Capt. Mary Feltault
Mr. William B. Lopp
Mr. Mike Van Aeteren
Mr. Bill Pehlivanian
Will Carter
Senator Dennis DeConcini
Mr. David R. Annis
Capt. Sally Watson
Col. Tim Peppe
Mr. Jack Koelsch
WCOOI JaIIP.,. 1
Regional Office
312 Directors DriVe. Knoxville. Ter:....essee 37923.615-690-3211
-------
IE INTERNATIONAL
TECHNOLOGY
CORPORATION
RECORD OF TELEPHONE CALL
DATE:
TIME:
July 10, 1992
Project Name:
Williams AFB
Project Number:
409735
Call from:
Will Carter ~ /'
"
Call to:
Steve Talley
Summary (Decisions/Specific Actions)
I returned Mr. Talley's call and informed him that we had received the information and
product that he had sent and said that there would be no formal response until the
responsiveness summary. I also notified him that there could be no assured action
accepting or rejecting his proposed product until the remedial design for OU-2 was
funded and initiated. I indicated that IT was doing a cursory examination of his product
for its potential use on this and other jobs but that this was not a part of our scope with
Williams AFB. I, therefore, told him that he should not rely specifically on our efforts
to either accept or reject his product for future use. I also notified him that his interest,
product, and name would be transmitted to other agencies who might be engaged in the
remedial design process.
Required Action:
Prepared By:
Will Carter
Distribution:
Jack Koelsch
Bill Mabson
Bill Lapp
WCOOSJaI
-------
ECOLOGY TECHNOLOGIES INTERNATIONAL
Mr. William Lapp (H-9-1)
U.S.ErMronmentfa1 Protection Agency
7S Hawthorne Street
Federal Enforcement Section
San Francisco, California 94105
17 June, 1992
Dear Mr. Lapp,
h was a pleasure to attend the wen-organized and presented meeting held at the
Rendezvous Center the 16th of J1Dle. I appreciate your "sidewalk consultation" regarding
the potential for use of FyreZyme in this and other petroleum product spin sites. Our
infonnationaJ packet is enclosed.
i have submitted a request that our new product, FyreZyme, be selected as the nutrient for
the bioremediation component of OU-2 at W AFB. FyreZyme, as the enclosed literature
explains, serves as a rich source of biol~c metabolic enzymes to initiate the oxidation of
benzene and other contaminants. FyreZyme's sugars and amino acids stimulate bacterial
growth; by Darwinian selection, those bacteria capable of continuing the metabolism of
petroleum product increase in relative and actual numbers by several orders of magnitude.
FyreZyme aJso contains naturally-produced bioemulsifiers which help increase the surface
area of the petroleum aggregates. An integral biodegradable surfactant moiety increases the
penetration of FyreZyme into less-titan-ideal soil enviromnents such as are present in OU-
2, and also helps mobilize petroleum product within the soil pore spaces.
The positive feedback bioremediation system which develops with the utilization of
FyreZyme, water, and atmospheric oxygen has been proven in both bench and field tests.
Toxicity studies verify the wide margin of safety of FyreZyme. FyreZyme is the least
expensive of aD currently available environ.1TIentaDy "friendly" bioremcdia!ion enhancing
agents. FyreZyme has proven highly effectP,~ in suppressing VQC release, and we are in
the process of developing off-gas treatment me1hodologies which wiD dramatically decrease
the cost of air ponution control. Our field testing ofVOC control may not be completed by
July 7, so I would like to keep that door open for further communication.
Ecology Teclmologies IntenWional, Inc. would like to offer our services in further
petroleum-spiII remediation in State and Federal sites, and would appreciate an opportunity
to discuss the technology in person with you and your technical staff. Your guidance as to
how we can participate in field demonstrations and testing as wen as in actual site wad
would be most valuable. Tom Schruben bas advised us to meet with representatives within
the Regions, and we would be pleased to come to San Francisco for such a
"brainstonning" session.
Sincerely,
.'
/-? ; . -- )-.' .
_.~::tY - /kr elf- c(...c'. - .~
Robert H. Meaders MD
Research Director
Corporate Office. 6119 E. Star Valley S!. . Mes<.. Arizona 85205 . Phone: 602-985-5524 . FAX: 602-985-2988
-------
I:\" -SITl" FIX.-\TI O:\" CO:\IPA:\"Y
Di<.uion 01 tnt RitnOTd P. MIlTTO}' Co.. In..
Environmental Contractors
P. o. Box ;15 . Chandkr. Arizona S;224-0515 . c6021821-0409
July 1, 1992
Mr. William Lopp (H-9-l)
u.s. Environmental Protection Agency
75 Hawthorne Street
Federal Enforcement Section
San Francisco, California 94105
Ref: Public Meeting-Proposed Cleanup, Operable Unit 2, WAFB
Subj: Recommendation for Alternative Cleanup Technology
Dear Mr. Lopp:
Enclosed with this letter, please find our Company brochure and a
video tape describing our in-situ bioremediation technology
methods and equipment. The reason for this letter is to present
our in-situ soil bioremediation Dual Auger System Technology as
an alternative cleanup method for the Liquid Fuel Storage Area,
Operable Unit 2, Williams Air Force Base.
The current proposed soil remediation plan, as presented at the
June 16, 1992 meeting, is to construct injection wells to a depth
of 25' on an as yet undetermined spacing pattern. An as yet
undetermined liquid nutrient is proposed to be injected into the
soil under pressure, via the injection wells. I would request
that you evaluate o~r in-situ injection and mixing technology, in
lieu of the currently proposed injection well system. The pro-
posed method of in-situ bioremediation treatment is not the most
efficient or cost effective in-situ soil bioremediation method
available today, as exhibited by the results of past and current
direct injection demonstration projects. The current S.I.T.E.
Demonstration Project presently taking place at Williams AFB has.
shown that the lateral/horizontal movement is limited. The soil
types encountered at Williams AFB will not allow for the uniform
lateral/horizontal movement of the injected liquid reagents and,
thus will not uniformly remediate the soil and will leave "hot"
spots.
Our technology, as described in the enclosed brochure and video
tape, has been accepted into the U.S.E.P.A.'s S.I.T.E. Program
for just this type of contamination. Additionally, later this
summer, working under a contract with the U.S.A.F., we will
demonstrate the unique and efficient injection and mixing feature
of our Dual Auger System Technology.
-------
Mr. William Lopp
July 1, 1992
Page 2
We are aware that it is the intention of all parties concerned,
that the cleanup at Williams AFB be successfully remediated .and
at the lowest possible cost to the American taxpayer. As a local
Arizona company, we would like to recommend a full scale pilot
program, utilizing our technology vs. the proposed injection well
method. The magnitude of the cleanup project at Williams AFB
would certainly justify such a full scale pilot test program.
I would very much appreciate hearing from you at
convenience.
your
earliest
~in rely,
-- t .,{t2t~/Jt"
-------
SOIL REMEDIATION by THERMAL DESORPTION
On-site soil remediation, thermal desorption service
DUSTCOATING, INC.
July 6, 1992
Captain Mary Feltault
Public Affairs Office
Williams Air Force Base, Arizona 85240
Hr. Hike Van Fleteren
Arizona Department of Environmental
3003 N. Central Avenue, Suite 502
Phoenix, Arizona 85012
Qual i ty
Hr. William Lopp (H-9-1)
u.s. Environmental Protection Agency
75 Hawthorne Street
Federal Enforcement Section
San Francisco, California 94105
RE:
PUBLIC COMMENT-PROPOSED PLAN FOR OPERABLE UNIT 2, WILLIAMS
AFB, ARIZONA
Dear Captain Feltault and Messrs. Van Fleteren and Lopp:
This letter is in response to the proposed plan for the cleanup
of groundwater and soil contamination at Williams Air Force Base
Operable Unit Number 2 (OU-2). After attending the public meeting
of June 16, 1992, we feel compelled to comment publicly regarding
the proposed plan. Specifically, our comments relate to the
rationale of the soil cleanup levels and the estimated costs
associated with the potential remedial method Alternative D, on-
site Thermal treatment. .
SOIL CLEANUP ACTION LEVELS
According to the Feasibility Study (FS) prepared for OU-2, the
average Benzene concentration at the site is 27.1 mg/kg. The
Summary of Contamination in the Proposed Plan for OU-2 states
that the objective of the corrective action is to treat soil to a
26 mg/kg action level for Benzene, while the current draft
Arizona cleanup level for Benzene in soil is 130 ug/kg. The
action level selected for OU-2 (which was derived by comparing
State action levels with risk-based concentrations calculated by .
the Air Force) is over 200 times higher than the current draft
State level itself. The proposed plan further states that the
Benzene. cleanup goal of 26 mg/kg is a "health-based protective
level." As Benzene is a known carcinogen, it is contradictory to
state that the 28 mg/kg Benzene cleanup level is in fact a
health-based protective level. Alternative C calls for millions
of dollars of expenditures over a minimum three year period. If
Alternative C is successfu~ in reaching the soil action level for
Benzene this will equate to only a four percent reduction in the
concentration of that compound in the soil.
3039 North Scottsdale Road
.
Scottsdale, Arizona 85251
.
(602) 941-2261
-------
SOIL REMEDIATION by THERMi.. ~ DESORPTION
On-site soil remediation, thermal desorption service
DUSTCOATING, INC.
The FS further states that the average Total Petroleum
Hydrocarbon (TPH) concentration for soil at OU-2 is 2,842.9
mg/kg. While the current draft state cleanup level for TPH is 100
mg/kg,there is no mention of a TPH cleanup level in the proposed
plan for OU-2. As the bulk of the contamination at OU-2 consists
of JP-4 TPH,the cleanup alternative selected should also include
an action level for TPH.
ALTERNATIVE D SOIL CLEANUP COSTS
Low temperature thermal desorption (LTTD) soil treatment is
capable of completely removing Benzene from soil along with
reducing TPH levels to less than 25 parts per million. These
treatment levels can be achieved rapidly and cost effectively
without harm to human health or the environment.
The remedial alternative evaluation in the proposed plan for OU-2
is correct in stating that Alternative D soil remediation with
LTTD technology .would result in a permanent solution,reduce
toxicity and be protective of the environment. The analysis is
flawed though regarding the estimated costs and the associated
time required to complete thermal treatment. The thermal
treatment option was evaluated based on utilizing a treatment
unit with a production rate of 10 tons per hour, processing
approximately 70,000 cubic yards of impacted soil over a period
of about two years, at a total cost of roughly 14 million dollars.
These costs and assumptions are inflated and unrealistic.
While it will be necessary to over-excavate a correspondingly
large volume of clean soil to successfully remove the JP-4
impacted areas down to a depth of 25 feet,a mobile LTTD unit with
a capacity properly sized to complete the job at hand would have
a production rate at least 3 times higher than what was used in
the feasibility analysis estimate. An estimated time frame to
complete the thermal portion only would be 10 to 12 months with a
more realistic per ton treatment cost in the neighborhood of $50
per ton. This would equate to approximately $4 to $5 million. By
including an additional $4 million for misc site preparations,
soil excavation and handling, fugitive emission controls,soil
analytical testing to verify treatment and backfilling, it is
really quite difficult to inflate the total cost estimate for
thermal soil treatment to more than $9 million dollars.
Based on the other alternatives,LTTD technology is quicker and
more cost effective and provides for a true environmental cleanup
with toxicity reductions in excess of 98 percent. The toxicity
reductions for alternative C are on the order of less than 10%,
ultimately with a much higher bottom line cost. There are
multiple unknowns related to the site-wide implementation and
effectiveness of in-situ bioremediation. There are also loosely
defined long-term operational and maintenance (O&M) expenses to
be incurred,which encompassed a rather broad range as defined in
the FS. The broad range of the O&M costs themselves implies a
high degree of uncertainty as to what the costs will ultimately
be. (2)
3039 North Scottsdale Road. Scottsdale, Arizona 85251
.
(602) 941-2261
-------
SOIL REMEDIATION by THERM} ~ ~ DESORPTION
On-site soil remediation, thermal desorption service
DUSTCOATING, INC.
Dustcoating has been in the thermal desorption business for over
four years. We have helped pioneer the. industry. We own and
operate mobile, low temperature thermal desorption units on a
.nationwide bases. We have successfully completed jobs in both the
public and private sector and have a real understanding of the
costs associated with thermal desorption treatment from both a
unit price and a "turnkey" perspective. We also understand how
these costs can vary depending on the geographical location of
the job site, and also how variations in cleanup levels and
permit requirements affect cleanup costs. These are variables
that are thoroughly addressed during the initial bidding and
later permit process as a project evolves.
In summary, the feasibility analysis for thermal treatment at OU-
2 failed to effectively demonstrate the inherent strong points
that make LTTD technology so effective on hydrocarbon cleanups
within the current environmental climate. Namely, the process is
rapid and thorough, cost effective,without harm to human health
or the environment, soil TPH concentrations are reduced to levels
that make the material suitable for virtually any use without
institutional controls or limits as to the re-use applications of
the material itself. .
There are no unknowns after the completion of thermal desorption,
the results are proof-positive. After several years of corrective
action as outlined in the proposed Alternative C, whether the
cleanup levels are met or not, the money will still get spent.
Respectfully Submitted,
Du coa~i~9Jncorporated
.?~~
Larr Z
Pre dent
~~
Rick Heetland
Arizona Representative
cc:
Mr Mike Breazeale
Mr Dale Libe
Capt. Kurt Mallery
Capt. Micheal Schanck
Mr William Mabson
Col. Dave R Love
Mr William Pehlivanian
3039 North Scottsdale Road
.
Scottsdale, Arizona 85251
.
(602) 941-2261
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