PB97-964408
EPA/541/R-97/198
January 1998
EPA Superfund
Record of Decision:
Hill Air Force Base, OU 8
Ogden, UT
9/30/1997
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Hill Air Force Base, Utah
Final
Record of Decision for an
Interim Remedial Action at
Operable Unit 8
May 1997
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FINAL RECORD OF DECISION
FOR AN INTERIM REMEDIAL ACTION AT
OPERABLE UNIT 8
HILL AIR FORCE BASE, UTAH
This is a primary document for Operable Unit 8 at Hill Air Force Base. It will be
available in the Administrative Record, which is maintained at the following locations:
Davis County Library
Central Branch
155 N. Wasatch Drive
Layton,Utah 84041
Hours: Mon - Thurs: 11:00 am - 9:00 pm
Fri - Sat: 11:00 am - 6:00 pm
• Environmental Management Directorate
OO-ALC/EMR
Building 5
7274 Wardleigh Road
Hill AFB, Utah 84056-5137
Contact: Mr. Charles Freeman (801)775-6951
Submittal Date: May 9,1997
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TABLE OF CONTENTS
PAGE
DECLARATION FOR THE RECORD OF DECISION
DECISION SUMMARY FOR THE RECORD OF DECISION
1.0 SITE NAME, LOCATION, AND DESCRIPTION 1-1
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES 2-1
2.1 Site History 2-1
2.2 Investigation History 2-1
2.3 Enforcement Activities 2-2
2.4 Highlights of Community Participation 2-2
2.5 Scope and Role of Operable Unit 8 Within Site Strategy 2-3
3.0 SUMMARY OF SITE CHARACTERISTICS 3-1
3.1 Hydrogeologic Setting 3-1
3.2 OU 8 Source Areas 3-2
3.3 Nature and Extent of Contamination 3-3
3.4 Conceptual Model of Contaminant Transport 3-5
4.0 PUBLIC HEALTH AND ENVIRONMENTAL IMPACTS 4-1
4.1 Human Health Risks 4-1
4.2 Environmental Risk 4-1
5.0 DESCRIPTION OF INTERIM REMEDIAL ACTION ALTERNATIVES 5-1
5.1 Development of Alternatives 5-1
5.2 Detailed Analysis of Alternatives 5-2
Alternative 1: No Action 5-2
Alternative 2: Ground-Water Extraction, Treatment with Carbon 5-2
Adsorption, Discharge to Storm Drain
Alternative 3: Ground-Water Extraction, Treatment with Air 5-3
Stripping, Discharge to Storm Drain
Alternative 4: Ground-Water Extraction and Discharge to 5-4
Sanitary Sewer
Alternative 5: Ground-Water Extraction, Treatment at IWTP, 5-5
Discharge to Sanitary Sewer
5.3 Comparative Analysis of Alternatives 5-5
5.3.1. Evaluation Criteria 5-5
5.3.2. Comparative Analysis of Alternatives 5-7
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Table of Contents
6.0 SELECTED REMEDY 6-1
6.1 Description of the Selected Remedy 6-1
6.1.1. Remediation Objectives and Performance Standards 6-1
6.1.2. Restoration Time Frame 6-2
6.1.3. Costs 6-2
6.2 Statutory Determinations 6-2
6.2.1. Protection of Human Health and the Environment 6-3
6.2.2. Compliance with Applicable or Relevant and Appropriate 6-3
Requirements
6.2.3. Cost Effectiveness 6-4
6.2.4. Utilization of Permanent Solutions and Treatment Alternative 6-7
Technologies or Resource Recovery Technologies to the
Maximum Extent Practical
6.3 Documentation of Significant Changes 6-7
RESPONSIVENESS SUMMARY
REFERENCES
APPENDIX A - PUBLIC MEETING TRANSCRIPT
APPENDIX B - WRITTEN COMMENTS AND RESPONSES
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Table of Contents
LIST OF TABLES
TABLE
NO. TITLE PAGE
3-1 Contaminants Detected on Base in OU 8 Ground Water 3-4
5-1 Summary of ARARs for Each Alternative 5-8
6-1 Summary of ARARs for the Selected Remedy 6-5
6-2 Summary of ARARs for the Optional Remedy 6-6
LIST OF FIGURES
FIGURE FOLLOWING
NO. TITLE PAGE NO.
1-1 Vicinity Map 1-1
1-2 Location of Operable Units 1-1
2-1 Site Map 2-1
3-1 Piezometric Surface Contour Map 3-1
3-2 TCE Isoconcentrations in Shallow Portion of the Shallow Aquifer 3-1
3-3 Ground-Water Contaminant Profile Along Southern Base Boundary 3-4
3-4 Conceptual Model of Contaminant Transport 3-5
4-1 Preliminary Exposure Pathway Diagram 4-1
5-1 Proposed Location of Ground-Water Extraction Wells and Area of 5-3
Attainment
6-1 Conceptual Interim Remedial Action Implementation Schedule 6-1
111
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Site Name and Location
Operable Unit 8
Hill Air Force Base, Utah
Weber and Davis Counties, Utah
Statement of Basis and Purpose
This decision document presents the selected remedy for an interim remedial action
(IRA) at Hill Air Force Base (Hill AFB) Operable Unit 8 (OU 8) in Weber and Davis
Counties, Utah. Five different interim remedial action alternatives were evaluated in
accordance with the Comprehensive Environmental Response, Compensation, and
Liability Act (CERCLA) as amended by the Superfund Amendments and Reauthorization
Act of 1986 (SARA) and, to the extent practicable, with the National Oil and Hazardous
Substances Pollution Contingency Plan (NCP). The selected remedy for the interim
remedial action at Hill AFB OU 8 is Alternative 4: groundwater extraction and discharge
to a sanitary sewer. If greater treatment efficiency, cost effectiveness or ease of
implementability can be established at a later date, other discharge alternatives would be
considered, such as the Industrial Wastewater Treatment Plant (IWTP). This decision is
based on the Administrative Record for Hill AFB. This remedial action is only an
interim measure and will be followed by the final remedy for OU 8.
Assessment of the Site
Actual or threatened releases of hazardous substances, if not addressed by implementing
the response action selected in this Record of Decision, may present an imminent and
substantial endangerment to public health, welfare, or the environment.
Current risks to human health associated with the contaminants at OU 8 are below levels
considered by the EPA to be significant. An interim remedial action is warranted based
on possible future risks to human health and the environment, to contain contaminants
while further information is gathered to characterize the site, and to evaluate possible
final remedial actions.
Description of the Selected Remedy
Operable Unit 8 is one of nine OUs at Hill AFB and is in the early stages of the CERCLA
process. The remaining OUs are at various stages in the CERCLA process. As OU 8
only includes ground water, this action will only address contaminated ground water.
Contaminated soil in the OU 8 area is being addressed by other soils-only OUs that
include OUs 3 and 7. The selected remedy for an interim action at OU 8 addresses the
potential future threat to human health and the environment by preventing the transport of
contaminated ground water to off-Base locations where exposure may occur. This
interim action is planned to be in operation until the final remedy for OU 8 is
implemented (anticipated to be within six years). This area and other areas containing
ground-water contamination at OU 8 will be addressed by the final remedy for OU 8.
The major components of this interim remedy for OU 8 include:
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• Contain contaminated ground water that is in excess of the Maximum
Contaminant Levels (MCLs) at the southern boundary of Hill AFB using a
series of vertical extraction wells located in the vicinity of the South Gate area
• Discharge ground water to the North Davis County Sanitation District
(NDCSD) sanitary sewer.
Statutory Determinations
This interim action is protective of human health and the environment, complies with
Federal and State applicable or relevant and appropriate requirements for this limited
scope action, and is cost-effective. This action is interim and is not intended to utilize
permanent solutions and alternative treatment (or resource recovery) technologies to the
maximum extent practicable for this operable unit. This interim action does not provide
on-site treatment; however extracted ground water will be treated at the NDCSD sanitary
sewer, which is a Publicly Owned Treatment Works (POTW). Because this action does
not constitute the final remedy for the operable unit, the statutory preference for remedies
that employ treatment that reduces toxicity, mobility, or volume as a principal element,
although partially addressed in this remedy, will be addressed by the final response
action. Subsequent actions are planned to address fully the threats posed by the
conditions at this operable unit. Because this remedy will result in hazardous substances
remaining on site above health-based levels, a review will be conducted to ensure that the
remedy continues to provide adequate protection of human health and the environment
within five years after commencement of the remedial action.
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RECORD OF DECISION
INTERIM REMEDIAL ACTION
OPERABLE UNIT 8
HILL AIR FORCE BASE, UTAH
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
Max H. Dodson Date
Assistant Regional Administrator
Office of Ecosystems Protection and Remediation
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RECORD OF DECISION
INTERIM REMEDIAL ACTION
OPERABLE UNIT 8
HILL AIR FORCE BASE, UTAH
C—STATE.OF U
ARTMENT OF ENVIRONMENTAL Q
DtSiimfR. Nielson, Ph.lT.
Executive Director
Date
UALITY
17
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Hill Air Force Base, Utah
Operable Unit 8
Decision Summary for the
Record of Decision
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Section 1
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1.0 SITE NAME, LOCATION, AND DESCRIPTION
Hill Air Force Base, Utah (Hill AFB) is located in northern Utah, about 25 miles north of
Salt Lake City and about five miles south of Ogden, Utah in Weber and Davis counties as
illustrated in Figure 1-1. Hill AFB covers an area of about 6,700 acres on the Weber
River Delta, a terrace that lies about 300 feet above the surrounding valleys. The delta
surface has slight to moderate relief with elevations varying from approximately
4,600 feet above National Geodetic Vertical Datum (NGVD) along the western boundary
of Hill AFB to approximately 5,000 feet above NGVD. The Great Salt Lake,
approximately 12 miles to the west, is presently at an elevation of approximately
4,200 feet above NGVD.
• 'i • .
Most of the southern part of Hill AFB is occupied by industrial facilities, equipment
storage areas, and administration buildings related to the aircraft maintenance mission of
the Base. By contrast, the northern part of Hill AFB has large open areas with groups of
buildings that were constructed as munition manufacturing plants, assembly plants or
storage facilities. Although the use of the old facilities has changed in recent years to
missile storage, maintenance, and testing, the building and facilities remain. Off-Base
land use in the Operable Unit (OU 8) area includes residential, commercial, and
agricultural. This area has undergone rapid residential and commercial development over
the last five years and agricultural use has declined. Crop production in this area is
primarily hay and alfalfa. There is pasture land and in some limited areas livestock are
raised.
In July 1987, Hill AFB was placed on the National Priorities List (NPL) under the
Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)
to address sites where hazardous liquid and solid wastes generated by installation
operations were disposed. These hazardous waste sites have been divided into nine
operable units (OUs) in accordance with a Federal Facility Agreement (FFA) executed in
1991 between the U.S. Air Force (USAF), State of Utah Department of Health (now the
Utah Department of Environmental Quality [UDEQ]), and the United States
Environmental Protection Agency (EPA) Region VOL
Operable Unit 8 is one of the newest operable units at Hill AFB following reorganization
in December 1993. The reorganization was to address existing and additional potential
source areas (contaminated soil sites within OUs 3, 7, and 9) separately and to
consolidate ground-water response actions beneath the southern industrial complex.
Consequently, OU 8 comprises the ground water within a shallow aquifer beneath the
on-Base industrial area and in the Layton and Clearfield areas south of the Base. This
area is shown on Figure 1-2.
Based on the available data, most of the ground-water contamination occurs in the
shallow aquifer beneath the industrial area and in off-Base locations directly south of
Hill AFB. Off-Base contamination predominantly occurs beneath the Layton area.
Although no ground-water contamination has been found in the Clearfield area,
additional investigations will be conducted to confirm that this is the case. For the
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R.3W.
R. 2W.
R. 1 W.
R. 1 E.
BOX ELDER CQ^
WEBER CO.
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IVUPAREA
S^tUk*
Crty
UTAH
HILL AIR FORCE BASE
VICINITY MAP
FIGURE 1-1
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o
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purpose of this Record of Decision (ROD), the Layton and Clearfield areas will be
referred to as the "off-Base areas."
The shallow aquifer beneath the industrial and off-Base areas is the principal hydro-
stratigraphic unit under investigation. It consists of up to approximately 200 feet of sand
interbedded with silt and clay and lies at approximately 65 to 200 feet below the ground
surface (bgs) on-Base, and about 1 to 50 feet bgs in off-Base areas. The shallow aquifer
overlies two deeper aquifers (Sunset and Delta aquifers) and is separated from them by a
thick sequence (over 100 feet) of low-permeability silts and clay (Feth et al, 1966).
The shallow aquifer could be (but has not been) classified as Class II - Drinking Water
Quality based on the State of Utah classification criteria and the observed quality of
ground water from uncontaminated wells in the vicinity. However, low yield private
wells in the shallow aquifer within the plume area are not used for domestic purposes.
This was confirmed by a comprehensive water user survey conducted in the Layton area
of OU 8 by Hill AFB (Montgomery Watson, 1996a).
The Sunset and Delta aquifers are approximately 300 and 600 feet bgs at OU 8,
respectively. These aquifers serve as a source of domestic water supply for Hill AFB and
surrounding communities and are classified as Class I - Irreplaceable Source of Drinking
Water or Class IIA - Current Source of Drinking Water (USGS, 1992).
According to the Environmental Assessment for OU 8 (Montgomery Watson, 1994a),
several wetlands have been identified, including Ponds 1 and 3 along the southern Base
boundary, areas along the Davis-Weber canal, and several small areas south of the canal
in the city of Layton. These wetlands are not known to be impacted by contamination at
OU8.
1-2
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Section 2
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2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES
2.1 SITE HISTORY
Hill AFB has been the site of military activities since 1920 when the western portion of
what is now the Base was activated as the Ogden Arsenal, an Army Reserve Depot. In
1940 and 1941 four runways were built and the Ogden Air Depot was activated. During
World War II, the Ogden Arsenal manufactured ammunition and was a distribution
center for motorized equipment, artillery, and general ordnance. The Ogden Air Depot's
primary operation was aircraft rehabilitation. In 1948, the Ogden Air Depot was renamed
Hill AFB, and in 1955, the Ogden Arsenal was transferred from the U.S. Army to the
U.S. Air Force. Since 1955, Hill AFB has been a major center for missile assembly and
aircraft maintenance. Currently, Hill AFB is part of the Air Force Materiel Command.
On-Base industrial processes in the OU 8 area associated with aircraft, missile, vehicle,
and railroad engine maintenance and repair include metal plating, degreasing, paint
stripping, and painting. These processes use numerous chemicals including chlorinated
and non-chlorinated solvents and degreasers, petroleum hydrocarbons, acids, bases, and
metals. In the past, chemicals and waste products were disposed of at the Industrial
Wastewater Treatment Plant (IWTP), in chemical disposal pits and landfills, and
off-Base. Disposal in chemical pits and landfills was discontinued by 1980. All waste
products are currently treated at the IWTP, recycled on-Base, or sent to off-Base
treatment or disposal facilities.
2.2 INVESTIGATION HISTORY
Investigations conducted in the OU 8 area include early investigations of OU 3, OU 7,
and the UST sites. Further details can be found in the Final Data Summary and
Recommendation Report for OU 8 (DSRR; Montgomery Watson, 1995A). As
investigation data became available, the apparent extent of ground-water contamination
in on- and off-Base areas was greater than originally expected. Because of this, Hill
AFB,EPA, and UDEQ agreed that further ground-water investigation and/or potential
remediation efforts in the general area would be best facilitated by forming a separate
operable unit (OU8).
Operable Unit 8 (Figure 1-2) is comprised of ground water underlying the southern
industrial area of the Base and areas immediately south of the Base. Contaminated
ground water occurs in on-Base and in off-Base areas. Some of the sources which likely
contributed to ground-water contamination within the Base have been identified, such as
the soils at Operable Units 3 and 7, as well as several underground storage tank (UST)
sites (Figure 2-1). Other facilities in the southern industrial complex are in the early
stages of investigation as part of Operable Unit 9. The contribution of the Operable Unit
9 sites are not fully understood at this time.
Hill AFB is presently conducting ground-water monitoring at OU 8. The results of the
first and second round of ground-water monitoring are presented in the Final First and
Second Monitoring Rounds Data Evaluation Report for OU 8 (Montgomery Watson,
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,./•'
>
..V^ TON
EXPLANATION
tui«o »no :aco«0 » -vn « UM
. HILL AIR FORCE BASE
OPERABLE UNIT B
SITE MAP
FIGURE 2-1
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1995d). More recent efforts have focused on delineating the contaminant plume and
defining aquifer characteristics along the southern Base boundary. Investigations have
included cone penetrometer testing (CPT) and hydropunch sampling in which water
samples are collected directly through CPT rods (this sampling technique is similar to the
Hydropunch® procedure and will be referred to as "hydropunch" for consistency with
other OU 8 documentation); installing and sampling monitoring wells; installing
extraction wells and piezometers; and conducting three constant pumping rate aquifer
tests. The results of these activities are summarized in the Interim Remedial Action Field
Work Data Summary and Remedial Design Technical Memorandum for OU 8 (IRA Tech
Memo; Montgomery Watson, 1996b). Additional work associated with the OU 8
Remedial Investigation (RI) is ongoing.
2.3 ENFORCEMENT ACTIVITIES
In July 1987, Hill AFB was placed on the CERCLA National Priorities List (NPL) by the
EPA. In 1991, Hill AFB entered into a Federal Facilities Agreements (FFA) between the
U.S. Air Force (USAF), the State of Utah Department of Health (now the UDEQ), and
the EPA. The purpose of the agreement was to establish a procedural framework and
schedule for developing, implementing, and monitoring appropriate response actions at
Hill AFB in accordance with existing regulations. Seven operable units were initially
defined under the FFA and two more operable units (OUs 8 and 9) have since been
added. This Record of Decision (ROD) is for an interim remedial action for OU 8 that
will be performed along the southern boundary of the Base in the vicinity of the South'
Gate. There have been no removal actions, notices of violation, or other enforcement
actions taken at OU 8 prior to this ROD.
2.4 HIGHLIGHTS OF COMMUNITY PARTICIPATION
The public participation requirements of CERCLA Section 113(k)(2)(B)(i-v) and
Section 117 have been met for OU 8. Hill AFB has a Community Relations Plan that
was completed in February 1992. The community relations activities include: (1) a
Restoration Advisory Board (RAB) which meets at least quarterly and includes
community representatives from adjacent counties and towns, (2) a mailing list for
interested parties in the community, (3) a quarterly newsletter called "EnviroNews,"
(4) visits to nearby schools to discuss environmental issues, (5) community involvement
in a noise abatement program, (6) semi-annual town council meetings, (7) opportunities
for public comment on remedial actions, (8) community interviews, and (9) support for
the community for obtaining technical assistance grants (TAGs).
The Interim Remedial Action (IRA) Focused Feasibility Study (FS) for the Base
Boundary, Operable Unit 8 (Focused FS; Montgomery Watson, 1995b) and the Proposed
Plan for an Interim Action at Operable Unit 8 (Montgomery Watson, 1995c) were
released to the public and are available in the Administrative Record maintained in the
Davis County Library and at the Environmental Management Directorate at Hill AFB.
The notices of availability for these documents were published in the Salt Lake Tribune,
Ogden Standard Examiner, and Hilltop Times. A public comment period was held from
August 8, 1995, through September 7, 1995, and a public Open House was held on
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August 17, 1995. At this meeting, representatives from Hill AFB, EPA, and the UDEQ
answered questions about the site and the selected remedy. Copies of all written
transcripts and verbal public comments received at that Open House are presented in the
Responsiveness Summary of this document for inclusion in the Administrative Record
(also see Appendices A and B). The decision for this site is based on the Administrative
Record.
2.5 SCOPE AND ROLE OF OPERABLE UNIT 8 WITHIN SITE STRATEGY
Operable Unit 8 is one of nine operable units at Hill AFB and is in the early stages of the
RI/FS process. The remaining operable units are at various stages in the CERCLA
process. The remedial actions planned for the various operable units are independent of
one another. This interim remedial action addresses contaminated ground water along
the southern boundary of Hill AFB. The interim remedy selected for OU 8 addresses
future threats to human health and the environment by preventing ground-water transport
of contaminants to off-Base areas, thereby controlling the volume and areal extent of
contamination and reducing future potential off-Base risk and cleanup costs. The interim
remedy selected for OU 8 would contain the migration of contaminants at the southern
boundary of Hill AFB by removing ground water with a series of vertical extraction
wells.
2-3
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Section 3
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3.0 SUMMARY OF SITE CHARACTERISTICS
3.1 HYDROGEOLOGIC SETTING
The shallow aquifer at OU 8 generally consists of sand interbedded with silt and clay.
Because of lateral discontinuities and the interbedded nature of the sand, silt, and clay
layers, ground water occurring in the deeper units of the shallow aquifer is hydraulically
connected to the shallower ground water in the overlying units. The interbedded sand
units, which have a higher hydraulic conductivity than the surrounding clay and silt units,
may provide preferential flow paths for ground-water and contaminant transport.
Because the sediments underlying OU 8 were deposited in a deltaic environment, these
'interbedded sand units probably represent distributary channels of the main ancestral
Weber River. If so, they may extend for fairly long distances as discrete units within the
finer-grained sediments. Consequently, they may provide preferential pathways for
transport of ground-water contaminants to off-Base areas. The heterogeneous nature of
the aquifer results in tortuous ground-water flow and contaminant transport paths, leading
to irregularly shaped contaminant plumes.
The interbedded nature of the aquifer may also result in the development of locally
confined (i.e., artesian) conditions or perched ground water. Localized zones of perched
ground water underlie the IWTP Sludge Drying Beds (based on the results of the OU 3
Phase I and n RI studies).
Ground-water recharge of the shallow aquifer at OU 8 is probably from infiltration of
precipitation at OU 8 and from ground-water through flow from the east. The ground-
water through flow probably originates from infiltration of precipitation in the
topographically high areas east of OU 8. Based on ground-water elevation contours
(shown on Figure 3-1), Ponds 1 and 3 appear to be significant local sources of recharge to
the shallow aquifer beneath OU 8. Discharge of ground water from the shallow aquifer at
OU 8 probably occurs via seeps, springs, field drains, streams, low yield private wells
(not used for domestic purposes), and evapotranspiration to the south in the cities of
Layton and Clearfield.
As of February 1997, ground water beneath OU 8 occurred at depths ranging from 3 feet
below ground surface (bgs) in several wells in the off-Base area to 173 feet bgs north of
the west ramp area of the 388th Fighter Wing (i.e. northern most portions of the OU 8
contaminant plume, as illustrated in Figure 3-2). Based on ground-water elevation
contours illustrated in Figure 3-1, shallow ground water underlying the industrial area is
flowing to the west and northwest. Shallow ground water underlying the Berman Pond
and Pond 1 areas flows to the northwest, west, and southwest. Shallow ground water
beneath Pond 3 flows away from the pond, particularly to the southwest. Based on the
configuration of the ground-water surface, both Pond 1 and Pond 3 appear to recharge the
shallow aquifer, influencing the shallow ground-water flow system, by creating ground-
water divides near both ponds. Ground water on one side of the divide created by Pond 1
flows northwest, while ground water on the other side flows to the southwest. Near Pond
3, ground water east and north of Pond 3 flows northeast, eventually changing to a north-
northwesterly flow near the OU 7 sites in the industrial area. Ground water south of
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EXPLANATION
HILL *1R FORCE BASE
OPERABLE UNIT 6
PIEZOMETRIC SURFACE
CONTOUR MAP
iFEBRUARY 19971
FIGURE J-1
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EXPLANATION
I |5-10ug/l
10-50 ng/1
I "| 50-100ng/l
1 00-500 ug/l
>50° M9/I
TCE concentration
(H9/U
Not delected
* Monitoring well location
Hydropunch sampling
location
Note: 1996 data was used to
create this map
"" '
,
Hi&AFB Bountary -•*'*,» \ ,j * ' ,-
HILL AIR FORCE BASE
„ --'~j OPERABLE UNIT 8
TCE ISOCONCENTRATIONS
* IN SHALLOW PORTION OF
THE SHALLOW AQUIFER
FIGURE 3-2 JJ
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Pond 3 flows essentially to the southwest. The ground-water surface in the Layton area
reflects the ground surface topography, with the horizontal hydraulic gradient essentially
to the southwest.
Horizontal Hydraulic Conductivity. Horizontal hydraulic conductivity values for the
shallow aquifer were calculated based on constant rate aquifer tests conducted in 3
extraction wells along the southern Base boundary. These 3 wells will be included as
part of the IRA system. The hydraulic conductivity ranged from 3 feet/day
(1 x 10"3 cm/sec) to 38 feet/day (1.3 x 10'2 cm/sec) in these wells. These values of the
hydraulic conductivity for the shallow aquifer are typical of published values for clean
sands, silty sands, and silts.
Vertical Hydraulic Conductivity. Vertical hydraulic conductivity values were
calculated using falling-head permeameter tests for 69 undisturbed soil samples. These
data are summarized in the DSRR (Montgomery Watson, 1995a). The vertical hydraulic
conductivity values range from 26 feet/day (9 x 10~3 cm/sec) to 1.1 x 10"* feet/day
(4 x 10"8 cm/sec). The permeability tests show that the vertical hydraulic conductivity
values are generally directly proportional with grain size. For example, the maximum
vertical hydraulic conductivity was measured in a clean sand (SP), while the minimum
vertical hydraulic conductivity was measured in a silty clay (CL) and clayey silt (ML).
Vertical hydraulic conductivities are generally one to two orders of magnitude less than
the horizontal hydraulic conductivities.
Vertical Hydraulic Gradients. Estimates of vertical hydraulic gradients for ground
water in the shallow aquifer were calculated using ground-water piezometric surface
elevations from monitoring well pairs that were close to each other and that were
screened at different depths. The vertical hydraulic gradients were calculated for each
well pair by dividing the difference in hydraulic head measured in the two wells by the
vertical distance in feet between the centers of the screened intervals of the wells. The
calculated values of the vertical hydraulic gradient for the five well pairs in the vicinity of
South Gate ranged from 0.3 to -0.1 (negative sign indicates upward vertical gradient).
Downward gradients exist at four of the five locations in the shallow aquifer at OU 8.
3.2 OU 8 SOURCE AREAS
The results of the studies associated with OU 3, OU 7, OU 9 and USTs have led to the
identification and investigation of potential contaminant source areas within OU 8.
Based on these investigations, several historical waste management areas have been
identified as sources for volatile organic contaminants (VOCs) and inorganic compounds
within OU 8 ground water, and other potential VOC sources may exist that have not yet
been identified. The following source areas have likely impacted ground water at OU 8:
Buildings 200 and 225 (OU 7); Berman Pond, the IWTP Sludge Drying Beds, the RVMF
and Pond 1 (OU 3); and the UST Sites 260 and 280. Pond 2, which is located off Base
(Figure 3-2), may also have impacted OU 8 ground water. The DSRR (Montgomery
Watson, 1995a) discusses these sites in detail.
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3.3 NATURE AND EXTENT OF CONTAMINATION
The following discussion of ground-water contaminants at OU 8 focuses on the
contaminants detected beneath the southern boundary of Hill AFB which is in the vicinity
of where this interim action will be implemented. Table 3-1 presents a summary of the
concentration ranges of volatile organic compounds (VOCs) detected in samples
collected from ground-water monitoring wells near the Base boundary. As indicated on
Table 3-1, several types of VOCs were detected in ground water at OU 8. The most
common and widespread of these compounds is trichloroethene (TCE). For comparison,
Federal and State of Utah drinking water standards are presented in the right column of
Table 3-1. The area within OU 8 where contaminants in ground water exceed Federal
and the State of Utah drinking water standards is shown on Figure 3-2. The area of
known contamination in excess of these standards extends from the north end of the
industrial complex south to the southern Base boundary. In off-Base areas, several areas
with VOC contaminants have been identified. Based on data presented in the IRA Tech
Memo (Montgomery Watson, 1996b), VOC contamination above the MCL at the Base
boundary is limited to a maximum depth of 140 feet bgs. No metals contamination has
been detected at the Base boundary. Maximum contaminant concentrations occurring in
on-Base ground water at OU 8 are also presented on Table 3-1. Contaminant
concentrations are generally lower in off-Base areas. The source or sources of the
off-Base contamination are being investigated. Refer to the DSRR (Montgomery
Watson, 1995a) for a detailed description of VOC contamination in OU 8 ground water.
Figure 3-3 illustrates the horizontal and vertical distribution of contaminants at the Base
boundary. The analytical results from hydropunch samples may not be quantitatively
comparable to results from monitoring/extraction well samples. However, hydropunch
samples are considered screening samples, and are distinguished from monitoring/
extraction well samples on Figure 3-3.
Figure 3-3 shows that contaminants were detected along the southern Base boundary
above MCLs in Monitoring Well U3-031 east of South Gate Drive, near Extraction Well
U8-201, and in Monitoring Wells U8-024, U3-043 and U8-051 west of South Gate Drive
near Extraction Wells U8-202 and U8-203. Contaminants were detected above MCLs
from the water table to a maximum depth of 140 feet bgs (in Monitoring Well U8-024).
The vertical contaminant distribution along the southern Base boundary appears to be
lithologically controlled and largely is restricted to the sand unit. Except for the
Monitoring Well U8-024, contaminants have not been detected in greater than trace
concentrations in the clay unit.
The compound detected most commonly at the highest concentrations in the ground
water at the Base boundary is trichloroethene (TCE), which was detected at a maximum
concentration of 88 micrograms per liter (ng/1) in the Monitoring Well U8-024 sample.
Figure 3-3 depicts the zones in the ground water along the Base boundary where any
contaminant was detected at a concentration greater than its MCL.
3-3
-------
TABLE 3-1
CONTAMINANTS DETECTED ON BASE IN OU 8 GROUND WATER
Compound
Max. Chemical
Concentrations in
OU 8 Ground
Water (On-Base)
(ug/1)
Max. Chemical
Concentrations in
Ground Water
Beneath Southern
Base Boundary*8)
(ug/1)
Utah and Federal
Standards for
Drinking Water
(Ug/1)
Trichloroethene (TCE)
1,1,1-Trichloroethane (1,1,1-TCA)
Tetrachloroethene (PCE)
1,2-Dichloroethane (1,2-DCA)
1 , 1 -Dichloroethene (1,1 -DCE)
Benzene
Chlorobenzene
Arsenic
Total Chromium
Hexavalent Chromium
2,000
1,200
130
480
190
23.9
370
147
3,460
2,130
88
3
6
48(Xb>
1
1
14
ND
ND
ND
5
200
5
5
7
5
100
50
50
50
ug/L Micrograms per liter
ND Not detected
Only those contaminants that exceed Utah or Federal standards for drinking water are shown on this
table.
(a) Analytical results included in this column are from monitoring wells U8-024, U8-047, U8-048,
U8-051, U3-031, and U3-043, (see Figure 2-1 for the locations of these wells).
(b) 1,2-DCA has not consistently been detected. 1,2-DCA was detected in Monitoring Well U8-024
at concentrations of 480 ug/L and 270 ug/L in February 1995 and July 1996, respectively, but was
not detected (<5 ug/L) in July 1995.
3-4
-------
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i
/
v
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| | ^IHl, ( l«| S*
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Drlm»d < uonalniinu lull rrxiKt lo (iy»)
ICC
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I I TCA
iny
VI
I UcnoiMlhvx
^ OcNuuMMiN
I I tlKNC*0«tlWI*
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0 100 200
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Mo/es. kV/ie
-------
Contaminants detected at levels above MCLs are restricted to a zone approximately
200 feet wide near Extraction Well U8-201 and a zone approximately 600 feet wide near
Extraction Wells U8-202 and U8-203. Contaminant concentrations are generally higher
west of South Gate Drive and extend to approximately 140 feet bgs.
The historical source of contamination in the shallow aquifer near the Base boundary at
OU 8 is Herman Pond. However, due to changes in the hydraulic regime at OU 8, this
contamination is likely residual. In the past, while Berman Pond was in use as an
industrial wastewater and stormwater retention pond, it caused mounding in the water
table beneath the pond and drove contaminated ground water to the south and southwest
toward the Base boundary. After the use of Berman Pond was discontinued in 1956 and
the pond was subsequently capped in the 1970s, the ground-water flow regime assumed
the current configuration shown in Figure 3-1. Ground-water mounding associated with
Ponds 1 and 3 began to have a stronger influence on ground-water flow near the Base
boundary. It now appears that ground-water flow in the general area may at least
partially divert residual Berman Pond contaminants north away from the Base boundary
toward the interior of the Base. A portion of the contaminants from Berman Pond
immediately along the southern Base boundary may also be migrating to the west and
ultimately to the south-southwest (off-Base).
3.4 CONCEPTUAL MODEL OF CONTAMINANT TRANSPORT
A conceptual model of contaminant migration, shown in Figure 3-4, has been developed
for OU 8. The model was based on the site physical characteristics and on the nature and
extent of contamination observed at OU 8 to date. The conceptual model is summarized
below. Section 4.0 of the DSRR (Montgomery Watson, 1995a) details the development
of this model.
In the area designated for the interim remedial action, the migration route of
contaminants is principally through the zones of higher permeability within the shallow
aquifer. At the southern Base boundary, the water table occurs at depths of
approximately 65 to 80 feet bgs and the aquifer consists of layers of sand and silty sand,
interbedded with silt and clay. At approximately 100 to 110 feet bgs a fine-grained unit
of silt and clay is present. At locations to the west of South Gate Drive this fine-grained
unit does not occur until 180 to 190 feet bgs.
Past waste handling practices at Berman Pond allowed contaminants to enter soil and
surface water which eventually migrated downward to the shallow ground water. After
entering the shallow ground-water system, contaminants (principally TCE) were
transported downward into the aquifer and to the southwest toward the Base boundary.
Recent sampling results indicate that VOC contaminants (above MCLs) have migrated
downward to a depth of approximately 140 feet bgs on the west side of South Gate Drive
at the southern Base boundary. Several hundred feet of low permeability sediments
separate the shallow aquifer from the deeper, drinking water aquifers (i.e., the Sunset and
Delta aquifers). These low permeability sediments have and should continue to
significantly impede deeper transport of contaminants from OU 8 to the drinking water
aquifers. Ground-water flow directions in the shallow aquifer indicate that dissolved
3-5
-------
Contaminant
Source*
ON BAM flWm «W»j BWHIAte
PONO,POND1,POH»8) <
VOCs
PCBs
BNAEs
Arsenic
cadmium, lead
Pesticides
Cyanide
Fuel hydrocarbon constituents
Operable Unit 7/US1V
BUUMNO 22S,BUIU>M0220
AND U8T SITES 260 and2BO
VOCs
PCBs
BNAEs
Arsenic, hexavalent chromium,
cadmium, beryllium, lead
Pesticides
Cyanide
Fuel hydrocarbon constituents
VOCs (TCE. TCA. DCE. CBz. DCA)
Operable Otttt 8
VOCs (TCE, TCA, DCE, PCE. CBz,
1.2-DCA, DCA, DCB,
petroleum hydrocarbons,
phenols)
Arsenic, total chromium, hexavalent
chromium
VOCs (TCE, DCE, DCA, TCA, 1,2-DCA. CBz)
t
«<«••;••
Unevaluated
VOCs (TCA, TCE. DCA, DCE)
I
EXPLANATION
f 1
PrBOOfflinAnl Minor
Pathway Pathway
TCA l.l.1-Tnchloro«hane
TCE Trfchkxoethen*
DCE 1.1-DicNonoemene
DCA Dichtoroethan*
ED6 Ethylena Dibronnida
DCA 1.2-Dichlonoe
-------
contaminants are moving from the southern Base boundary toward off-Base areas in a
south-southwest direction. These contaminants are transported by shallow ground water
in this direction. Some of this water is intercepted by one or more of the numerous field
drains south of the Base (see Figure 2-1). Once the contaminants enter the field drain
system, the transport rate is greatly accelerated.
3-6
-------
Section 4
-------
4.0 PUBLIC HEALTH AND ENVIRONMENTAL IMPACTS
This section presents a brief and qualitative description of the potential risks associated
with ground water at OU 8, particularly contaminated ground water at the southern Base
boundary. A qualitative risk assessment was performed because the OU 8 investigation
is in the early RI stage and information is not currently available for a full baseline risk
assessment. A baseline risk assessment for the entire Operable Unit will be conducted as
part of the upcoming RI for OU 8.
4.1 HUMAN HEALTH RISKS
Based on the conceptual model of contaminant transport, the potentially significant
pathways of human or environmental exposure to contaminants at OU 8 under current
and future conditions include exposure to shallow off-Base ground water. Figure 4-1
depicts the potential exposure pathways to VOC contaminants that are present at OU 8,
both on and off-Base. As shown in Figure 4-1, there is no current potential for exposure
and only low to negligible future potential for exposure (based on the combination of the
likelihood of pathway completion and the magnitude of exposure if a pathway is
completed) associated with contaminated ground water on Base, including ground water
at the southern Base boundary. While there is a low potential for pathway completion,
there could be significant risks if people were to use the shallow aquifer as their drinking
water supply. If contaminated ground water is transported to the off-Base area, current
and future (i.e., the near future where contaminated ground water could be used as
drinking water) off-Base ground-water users could be exposed to contaminants present in
the ground water. As shown in Figure 4-1, off-Base receptors include farmers or
landowners who may use or drink contaminated ground water collected in off-Base field
drains. Based on a ground-water users survey, all of these potential receptors are
connected to municipal water, but some still use ground water collected from field drains
for livestock watering and irrigation (Montgomery Watson, 1996b). The potential for use
of the water as tap water is considered higher off-Base than on-Base because Hill AFB
controls its on-Base water usage. Current and future ecological receptors also may be
exposed to contaminated ground water discharging from field drains.
4.2 ENVIRONMENTAL RISK
Air Quality. The VOC emissions from shallow on-Base ground water to the air are not
expected to be significant due to the depth of this ground water. VOC emissions from
field drains are also not expected to have a significant impact due to their low
concentrations.
Surface Water, Ground Water, and Wetlands. No streams, rivers, or lakes exist on
Hill AFB. The shallow aquifer is about 65 to 200 feet bgs on-Base and 10 to 50 feet bgs
off-Base. This aquifer has been impacted, and is the subject of the proposed interim
action. The shallow aquifer is separated by several hundred feet of silts and clays from
deeper aquifers. There is no evidence that the deeper aquifers have been affected by
VOCs. Numerous wetlands have been identified on Hill AFB and in the surrounding
communities. Several of these are within the boundaries of OU 8. Water quality of some
4-1
-------
PROJECT NO. 1166076.011801 12/12/95
Intermedia
Transport
Source Mechanism
Transport Exposure Transport
Medium Mechanism Medium
Intermedia
Transport
Mechanism
Exposure
Medium
Exposure
Route
Potential Potential For
Receptors Exposure
Residents; F —
Negligible
Residents; F [—| Negligible [
Workers; C, F [—| Negligible
Pumping or
Collection
from Field
Drains
Irrigation
Watering
Livestock
H
I Plant
Uptake
' —
Livestock
Uptake
Garden Crops
Tap Water H
Direct Contact
Milk/Beef
H
Air
Air
Inhalation
Residents; C, F
C = Current
F = Future
VOCs = Volatile Organic Compounds
HILL AIR FORCE BASE
OPERABLE UNIT 8
PRELIMINARY EXPOSURE
PATHWAY DIAGRAM
FIGURE 4-1
-------
of these wetlands in the Layton area may have been impacted. However, by
implementing this proposed interim action, the spread of contamination into this area will
be reduced and the net effect will be an improvement of the existing water quality.
Vegetation. All areas of OU 8 are highly modified and do not contain any threatened or
endangered plant species. No adverse effects on the local ecosystem are anticipated.
Wildlife. Hill AFB does not provide critical or important habitat for any wildlife species,
and no threatened or endangered species are known to inhabit the Base or the off-Base
area. Operable Unit 8 and the surrounding areas are developed, and the proposed interim
remedial activities and additional human presence will add no significant impact to
wildlife.
Archaeological Resources. There are no known cultural or archaeological resources on
Hill AFB or in the off-Base area in the vicinity of OU 8.
4-2
-------
Section 5
-------
5.0 DESCRIPTION OF INTERIM REMEDIAL ACTION ALTERNATIVES
As part of the Focused FS for OU 8 (Montgomery Watson, 1995b), five specific interim
remedial action alternatives were developed for ground-water containment to meet the
interim remedial action objectives (RAOs). Under Section 121 of CERCLA, a selected
interim remedial action must be protective of human health and the environment, and
must comply with (or waive) applicable or relevant and appropriate requirements
(ARARs). This interim action is to prevent further environmental degradation. ARARs
within that scope have been evaluated. ARARs pertaining to restoration alternatives will
be evaluated for the final remedy or remedies. The alternatives were then evaluated for
short-term effectiveness, long-term effectiveness and permanence; reduction of toxicity,
mobility, or volume through treatment; technical and administrative implementability;
and cost effectiveness. Then the alternatives were compared against these criteria for
selecting the recommended remedial measure alternative. Additionally, State and
community acceptance must be considered before a remedy is selected. This section
summarizes how the remedy selection process for OU 8 addressed these requirements.
5.1 DEVELOPMENT OF ALTERNATIVES
Interim remedial alternatives were developed by assembling technologies into
combinations that are applicable for the medium of concern at OU 8 (ground water). "The
steps that were used to develop remedial alternatives for OU 8 included development of
response objectives, remedial action objectives, and general response actions for
contaminated ground water, followed by a preliminary screening and evaluation of
technologies and process options. Response objectives include prevention of human
exposure to contaminated ground water through direct contact or ingestion, and enabling
long-term attainment of shallow ground-water remedial action objectives. Remedial
action objectives (RAOs) were developed to define the extent of the interim remedial
action. Based on the current understanding of the nature and extent of contamination,
exposure pathways, and potential risks associated with OU 8, the following RAOs were
established for an interim remedial action at OU 8:
• Contain ground water at the southern boundary of Hill AFB to prevent
off-Base transport of contaminants in excess of MCLs in the shallow ground
water and reduce future potential off-Base risks
• Reduce the spread of contaminants, thereby controlling the volume and areal
extent of contaminated ground water at OU 8
• Reduce future cleanup costs by controlling the spread of contamination.
General response actions identify basic actions that might be undertaken as part of an
interim remedial action. Several technologies may exist for each general response action.
The preliminary screening of technologies for each general response action involved
evaluation of technical implementability. In the process option evaluation, technically
implementable technologies were evaluated with respect to effectiveness,
5-1
-------
implementability, and cost. Details of the technologies evaluated and the evaluation
process used are presented in the Focused FS (Montgomery Watson, 1995b).
The technologies and process options that passed the screening criteria were assembled
into four alternatives. As required by the NCP process, the "No Action" alternative was
retained for the purpose of comparison.
5.2 DETAILED ANALYSIS OF ALTERNATIVES
Each alternative for this interim action uses hydraulic containment as the primary element
with different processes for ground-water treatment and disposal.
During the detailed analysis of alternatives for OU 8, each alternative was assessed
against nine evaluation criteria defined in the NCP to compare the relative performance
of the alternatives and to identify the advantages and disadvantages of each. This
approach was designed to provide sufficient information to adequately compare the
alternatives, select an appropriate interim remedial action, and satisfy CERCLA remedy
selection requirements. The detailed analysis of alternatives included developing and
further defining the volumes or areas of contaminated ground water to be addressed, the
technologies to be used, and the performance requirements associated with those
technologies. Also included in the Focused FS is an assessment and summary profile of
each alternative and a comparative analysis among the alternatives.
Alternative 1: No Action
The No Action Alternative involves taking no action until the final remedy for OU 8 is
implemented. This alternative is included as a basis of comparison with other
alternatives. As is common to all the alternatives, periodic monitoring of ground water is
included. Ground-water monitoring would include testing the ground-water quality both
upgradient and downgradient of the Base boundary in 10 monitoring wells. There are no
capital cost requirements for Alternative 1, but the annual operating and maintenance cost
is $74,000. The estimated six-year present-worth cost is $330,000.
Alternative 2: Ground-Water Extraction, Treatment with Carbon Adsorption,
Discharge to Storm Drain
Alternative 2 includes the following technologies:
• Ground-water extraction with vertical wells
• Ground-water treatment using carbon adsorption technology to reduce
contaminants in the water to acceptable levels
• Discharge of treated water to a storm drain
• Transport the used carbon containing potential hazardous waste to an off-Base
facility.
5-2
-------
Under this alternative, vertical extraction wells drilled along a 1.200-foot wide area along
the southern Base boundary (see Figure 5-1) would supply contaminated ground water to
an above-ground carbon adsorption system for treatment. Treated ground water would
then be discharged to the storm drain. A ground-water monitoring program like that
described for Alternative 1 would be conducted as part of this alternative. In addition,
the monitoring program would be used to monitor system performance. Performance
would be evaluated with respect to current concentrations as a baseline. If contaminant
concentrations downgradient of the extraction system decrease with time, the system
would be considered to be performing as designed. However, if contaminant
concentrations increase downgradient during system operation, the system would need to
be reevaluated.
This alternative would contain ground water along a 1,200-foot long section at the
southern Base boundary to depths of approximately 140 feet bgs. This alternative would
also meet the objectives of the IRA by containing ground water on Base and preventing it
from migrating to off-Base areas and further impacting human health and the
environment. No treatability studies are planned for any of the alternatives in this interim
action. Operational information gathered during the duration of this IRA would be
evaluated with regard to effectiveness as to its potential to be used as part of the final
remedy. Alternative 2 would be easy to implement from a technical and administrative
standpoint. However, installation of the extraction system and conveyance piping would
traverse beneath the south entrance to Hill AFB, which would require coordination with
Base Civil Engineering. Off-Base transportation of spent carbon for regeneration and
reuse would require manifesting and possibly a modification of the existing State-issued
permit for Hill AFB under RCRA.
Capital cost requirements for Alternative 2 are $1,041,000, and the annual operating and
maintenance cost is $114,000. The estimated six-year present-worth cost is $1,552,000.
Alternative 3: Ground-Water Extraction, Treatment with Air Stripping, Discharge
to Storm Drain
Alternative 3 includes the following technologies:
• Ground-water extraction with vertical wells
• Ground-water treatment using an air stripper to reduce contaminants in the
water to acceptable levels
• Discharge of treated water to a storm drain.
Under this alternative, the extraction wells (as described in Alternative 2) would
discharge contaminated ground water to an above-ground air stripping system for
treatment. Treated ground water would then be discharged to the storm drain. A ground-
water monitoring and compliance program like that described for Alternative 2 would be
conducted as part of this alternative.
5-3
-------
EXPLANATION
Proposad ground wata* ••traction wall location
(Not lo tcata)
AIM Of artammam lor Wf Manm acton
Formar pond Ma; omaanfy capped or Mad
•OUTMOATt
Mtnon
CIMTCM
I T»mio
Swury
AfMOl
AtMraiMnl
T
TiwtiMnl Ptanl (IWTP)
r^
HILL AIR FORCE BASE
OPERABLE UNIT I
PROPOSED LOCATION OF GROUND-WATER
EXTRACTION WELLS AND AREA OF ATTAINMENT
FIGURES-1
-------
The SCREEN2 Model was used to estimate air emissions from the treatment system at
the Base boundary. In accordance with the UDEQ toxicity screening procedure, the
contaminant concentrations in air at the nearest receptor were evaluated. Due to the
proximity of the OU 8 interim action to the Base boundary, the nearest receptor point was
assumed to be at that boundary. Potential receptors that were considered included:
on-Base personnel, residential neighborhoods, and commercial developments.
Preliminary modeling results suggest that emissions from the air stripper would be well
below the UDEQ requirements, and that no air pollution control device would be
necessary for the air stripper off-gas. However, the UDEQ would need to be notified
before operating the air stripper.
This alternative would have similar containment and implementability requirements as
described for Alternative 2. Capital cost requirements for Alternative 3 are $989,000,
and the annual operation and maintenance cost is $110,000. The estimated six-year
present-worth cost is $1,481,000.
Alternative 4: Ground-Water Extraction and Discharge to Sanitary Sewer
Alternative 4 includes the following technologies:
• Ground-water extraction with vertical wells
• Discharge of extracted ground water to sanitary sewer.
Under this alternative, extracted ground water would be discharged directly to a sanitary
sewer. Previous monitoring results indicate that the volatile organic contaminants are
present primarily around Berman Pond and monitoring well U3-025 (Figure 3-1). Since
the proposed extraction system would be located at the southern edge of the plume, the
extracted ground water would contain dilute concentrations of VOCs. No ex-situ
treatment would be required to meet the discharge limits (primarily the total toxic
organics limit of 2.04 mg/1) established by the North Davis County Sanitation District
(NDCSD). This alternative would also include the ground-water monitoring and
performance program described for Alternative 2.
As with Alternative 3, this alternative would have similar containment and
implementability requirements as described for Alternative 2. Capital cost requirements
for Alternative 4 are $775,000, and the annual operating and maintenance cost is
$136,000. The estimated six-year present-worth cost is $1,385,000.
5-4
-------
Alternative 5: Ground-Water Extraction, Treatment at IWTP, Discharge to
Sanitary Sewer
Alternative 5 includes:
• Ground-water extraction with vertical wells
• Conveyance of extracted ground water to the IWTP for treatment
• Discharge of treated ground water to the sanitary sewer.
Under this alternative, contaminated ground water would be extracted and discharged to
an on-Base industrial wastewater pipeline and transported to the IWTP. At the IWTP,
extracted ground water would be treated through an existing, above-ground air stripper.
Treated water would be discharged to a sanitary sewer through an existing connection.
Air quality and local discharge limits would be met under existing permits for the IWTP.
This alternative would also include the same ground-water monitoring and performance
program described for Alternative 2. The treatment components presented as part of this
alternative have been slightly modified from what was reported in the Focused FS
(Montgomery Watson, 1995b). The modification includes eliminating carbon treatment
of air emissions, which is consistent with the current permitted operation at the IWTP.
This alternative would have similar containment and implementability requirements as
described for Alternative 2. Capital cost requirements for Alternative 5 are $776,000,
and the annual operating and maintenance cost is $223,000. The estimated six-year
present-worth cost is $1,764,000.
5.3 COMPARATIVE ANALYSIS OF ALTERNATIVES
Each of the five alternatives described above was evaluated against nine evaluation
criteria to assess their relative advantages and disadvantages, and to identify key tradeoffs
that were balanced in selecting an interim action alternative for ground-water
containment. Based on this comparison, a preferred alternative was selected for an
interim action at OU 8.
5.3.1. Evaluation Criteria
The alternatives were compared with respect to nine evaluation criteria that have been
developed under CERCLA to address the technical and policy considerations associated
with selecting among the remedial alternatives. The nine evaluation criteria are described
below.
5-5
-------
Threshold Criteria
Threshold criteria include overall protection of human health and the environment and
compliance with ARARs. These threshold criteria must be met by any given alternative
before it can be evaluated under the five balancing criteria.
1. Overall Protection of Human Health and the Environment describes whether
the alternative as a whole achieves and maintains adequate protection of human
health and the environment.
2. Compliance with ARARs describes whether the alternative complies with
- ARARs or, if a waiver is required, how it is justified. Other information from
advisories, criteria, and the guidance "to be considered" is also addressed.
Only those ARARs within the scope of this interim action are evaluated in this
ROD. Compliance with ARARs for the entire site will be discussed in the
feasibility study (FS) for OU 8. Additionally, the final action for OU 8 also will
be developed during the FS process.
Balancing Criteria
The five balancing criteria form the basis of the comparative analysis because they allow
tradeoffs among the alternatives requiring different degrees of performance.
3. Short-Term Effectiveness examines the effectiveness of alternatives in
protecting human health and the environment during the construction and
implementation of a remedy and until the response objectives have been met.
4. Long-Term Effectiveness and Permanence refers to the ability of an alternative
to provide reliable protection of human health and the environment over the long
term.
5. Reduction of Toxicity, Mobility, and Volume (TMV) Through Treatment
refers to the preference for treatment technologies that meet this criterion at the
site.
6. Implementability evaluates the technical and administrative feasibility of the
alternatives and the availability of the goods and services needed to implement
them.
7. Cost refers to the capital, indirect, and operation and maintenance costs of each
alternative. Costs are estimated and are expected to provide accuracy of plus
50 percent to minus 30 percent for a six-year period. The six-year period is used
as a common point of comparison for evaluating the interim action alternatives
(i.e., the time until a final OU 8 remedy is implemented). Cost can only be a
deciding factor for alternatives that are equally protective of human health and the
environment.
5-6
-------
Modifying Criteria
The modifying criteria described below are generally addressed in response to comments
from the State and the public after issuance of the Proposed Plan.
8. State Acceptance indicates whether the State agrees with, opposes, or has no
comment on the preferred alternative.
9. Community Acceptance indicates whether the community agrees with, opposes,
or has no comment on the preferred alternative.
5.3.2. Comparative Analysis of Alternatives
In this section, the alternatives are compared to evaluate their relative performance
according to each of the evaluation criteria. The objective of the comparison is to assess
the relative advantages and disadvantages of the alternatives and to identify the key
tradeoffs that must be balanced in selecting a preferred alternative. A comparison
between alternatives for each criterion is briefly discussed in the following paragraphs.
Overall Protection of Human Health and the Environment. Implementation of
ground-water containment alternatives (i.e., Alternatives 2, 3, 4, and 5) would represent a
preliminary step in achieving long-term protection of human health and the environment.
Each of these alternatives would prevent transport of contaminants to off-Base areas.
The no action alternative does not minimize transport of contaminated ground water to
off-Base areas or mitigate potential threats to human health and the environment.
Compliance with ARARs. MCLs and State of Utah water quality standards are not
ARARs because Alternatives 2 through 5 are designed as interim containment actions
(not aquifer restoration actions). However, the area of containment that will be
established for each alternative will be defined by the area where contaminant
concentrations are in excess of MCLs and State of Utah water quality standards. These
ARARs will be addressed as part of the final remedy or remedies selected for OU 8.
Because Alternative 1 involves no action except ground-water monitoring, the only
ARARs for this alternative are ground-water monitoring ARARs.
The potential ARARs that will be met during implementation of Alternatives 2 through 5
include chemical- and action-specific ARARs. All ARARs that must be met for each
alternative are listed in Table 5-1.
All of the alternatives are administratively feasible, but each must comply with ARARs
or obtain or revise permits pertaining to discharge of the extracted water and waste
handling. In terms of discharge, the treated water would be discharged to a storm drain
(Alternatives 2 and 3), sanitary sewer (Alternative 4), or to an industrial sewer (which
discharges to the sanitary sewer) that goes to the publicly owned wastewater treatment
plant (Alternative 5). For Alternatives 2 and 3, Hill AFB's stormwater discharge permit
would need to be revised to include the discharge from the treatment systems for these
5-7
-------
TABLE 5-1
SUMMARY OF ARARs FOR EACH ALTERNATIVE
-------
TABLE 5-1
SUMMARY OF ARARs FOR EACH ALTERNATIVE
(2 of 4)
Alternative
ARARs With Which the Alternatives Must Comply
ARAR Type
Will Alternative Meet ARAR? How Will It Comply?
Alternative 3
(Air Stripping, Discharge to
Storm Drain)
V
•R307-1-2UAC
(Utah Air Conservation Rules - general requirements)
• R307-1-3UAC
(Emission standards for control of installations)
•R307-1-4UAC
(Emission standards)
•R307-10UAC
(Utah NESHAPs Standards)
• R307-I2UAC
(Fugitive Dust Emission Standards)
• R307-14UAC
Emission Standards for Ozone Non-Attainment Areas, Davis and Salt
Lake Counties)
• R3I5-2UAC
(General requirements - identification and listing of hazardous waste)
•R3I5-5UAC
(Hazardous waste generator requirements)
• R315-8-2.9
(Standards for Owners and Operators of Hazardous Waste Treatment
Storage and Disposal Facilities; General Facility Standards; Location
Standards)
• R315-8-6UAC
(Ground Water Protection Standards for Owners and Operators of
Hazardous Waste TSDFs)
• R317-1 UAC
(Definitions for water pollution rules and general requirements)
•R317-2 UAC
(Standards for quality of waters of the State)
•R317-6UAC
(Ground-water quality protection rule)
•R317-8 UAC
(Utah pollution discharge elimination system)
• R655-4 UAC
(Standards for drilling and abandonment of wells)
• 40 CFR Part 50
(Primary and secondary air quality standards)
• 40 CFR Part 61 subpart A
(NESHAPs Standards)
•40 CFR Parts 122-125
(National pollution discharge elimination System)
• 40 CFR Part 261
(Identification and listing of hazardous waste)
• 40 CFR Part 264, Subpart F
(Requirements for detection and containment of releases)
Ap A Yes -Prohibits emission of air contaminants in sufficient quantities to cause air pollution.
Ap A, C Yes - Air emissions during remediation will be controlled to comply with air emissions
requirements.
Ap A, C Yes - Air emissions during drilling would be controlled to comply with air emissions requirements.
Ap C Yes - Air emissions would be controlled to comply with this rule.
Ap A Yes -Fugitive dust emissions generated during the IRA construction activities would be controlled
to meet the established fugitive dust emission standards.
Ap A Yes -Air emissions would be controlled to comply with this rule.
Ap A Yes - Determines potential waste classification and applicability of land disposal restrictions and
other solid and hazardous waste rules.
Ap A Yes - Alternative will meet all requirements involving off-site handling and disposal of hazardous
waste.
Ap L Yes-Any newly constructed treatment facilities will be outside 100-year flood plains.
R A. C Yes - Complies with ground-water monitoring provisions.
Ap C Yes - Alternative will be designed to comply with all rules and general requirements for storm drain
discharge.
Ap C Yes - Complies by treating ground water to water quality standards before discharge.
A.C Yes -The Utah Ground Water Protection Rule establishes numerical clean-up levels and other
performance standards for contaminated ground water. Although no determination has been made
concerning whether this Rule is an applicable or relevant and appropriate standard at OH 8, the
standards required by the Ground Water Quality Protection Rule will be met by complying with
drinking water MCLs.
Ap A,C Yes - Complies by treating ground water to water quality standards before discharge.
Ap A Yes - Design of all extraction and monitoring wells will be in accordance to this standard.
Ap C Yes - Air emissions are expected to be well below established standards.
Ap C Yes - Complies because air emissions of hazardous pollutants will be below the established
standards.
Ap A.C Yes - Alternative will be designed so that all discharge effluent will comply with discharge permits
issued to Hill AFB.
Ap C Yes - All hazardous waste will be classified according to this ARAR.
Ap A Yes - Complies by providing ground-water monitoring.
ARAR Applicable or relevant and appropriate requirement
RCRA Resource Conservation and Recovery Act
Ap Applicable
TSDF Treatment. Storage, and Disposal Facility
UAC Utah Administrative Code
A Action-Specific ARAR
L Location-Specific ARAR
R Relevant and Appropriate
C Chemical-Specific ARAR
-------
TABLE 5-1
SUMMARY OF ARARs FOR EACH ALTERNATIVE
(3 of 4)
Alternative
ARARs With Which the Alternatives Must Comply
ARAR Type
Will Alternative Meet ARAR? How Will It Comply?
Alternative 4
(Discharge lo Sanitary
Sewer)
V
t—*
O
•R307-1-2UAC Ap
(Utah Air Conservation Rules • general requirements)
•R307-I-3UAC Ap
(Emission standards for control of installations)
•R307-MUAC Ap
(Emission standards)
•R307-1-4UAC Ap
(Emission standards)
•R307-10UAC Ap
(Utah NESHAPs Standards)
•R307-12UAC Ap
(Fugitive Dust Emission Standards)
•R307-14UAC Ap
Emission Standards for Ozone Non-Attainment Areas, Davis and Salt
Lake Counties)
•R315-2UAC Ap
(General requirements - identification and listing of hazardous waste)
•R315-5UAC Ap
(Hazardous waste generator requirements)
• R315-8-6 UAC R
(Ground Water Protection Standards for Owners and Operators of
Hazardous Waste TSDFs)
• R317-1 UAC Ap
(Definitions for water pollution rules and general requirements)
• R317-2 UAC R
(Standards for quality of waters of the Stale)
•R317-6 UAC Ap
(Ground-water quality protection rule)
•R317-8UAC R
(Utah pollution discharge elimination system)
• R655-4 UAC Ap
(Standards for drilling and abandonment of wells)
•40 CFR Parts 122-125 Ap
(National pollution discharge elimination System)
• 40 CFR Part 264. Subpart F Ap
(Requirements for detection and containment of releases)
• 40-CFR Part 270 Ap
(Hazardous waste permit program)
•40CFRPart403 Ap
(National pretreatment standards)
A Yes -Prohibits emission of air contaminants in sufficient quantities lo cause air pollution.
A, C Yes - Air emissions during remediation will be controlled lo comply with air emissions
requirements.
A, C Yes - Air emissions during drilling would be controlled to comply with air emissions requirements.
A, C Yes - Air emissions would be controlled to comply with this mle.
C Yes - Air emissions would be controlled to comply with this mle.
A Yes -Fugitive dust emissions generated during the IRA construction activities would be controlled
to meet the established fugitive dust emission standards.
A Yes -Air emissions would be controlled lo comply with this rule.
A Yes - Determines potential waste classification and applicability of land disposal restrictions and
other solid and hazardous waste rules.
A Yes - Alternative will meet all requirements involving off-site disposal of hazardous waste.
A Yes - Complies with ground-water monitoring provisions.
C Yes - Alternative will be designed to comply with all rules and general requirements for sanitary
sewer discharge.
C Yes - Ground water will be treated at the POTW
A.C Yes -The Utah Ground Water Protection Rule establishes numerical clean-up levels and other
performance standards for contaminated ground water. Although no determination has been made
concerning whether this Rule is an applicable or relevant and appropriate standard at OU 8, the
standards required by the Ground Water Quality Protection Rule will be mcl by complying with
drinking water MCLs.
A.C Yes - Ground water will be treated at the POTW
A Yes - Design of all extraction and monitoring wells will be in accordance to this standard.
A.C Yes - Alternative will be designed so that all discharge effluent will comply with discharge permits
issued lo Hill AFB.
A Yes - Complies by providing ground-water monitoring.
Yes - All discharged water contaminants will be within the standards established by this ARAR.
A Yes - All remedial technology units will be managed in accordance with this ARAR.
ARAR Applicable or relevant and appropriate requirement
RCRA Resource .Conservation and Recovery Act
Ap Applicable
TSDF Treatment. Storage. and Disposal Facility
UAC Utah Administrative Code
A Action-Specific ARAR
L Location-Specific ARAR
R Relevant and Appropriate
C Chemical-Specific ARAR
-------
TABLE 5-1
SUMMARY OF ARARs FOR EACH ALTERNATIVE
(4 of 4)
Alternative
Alternatives
(Treatmenl at IWTP and
Discharge lo Sanitary
Sewer)
ARARs With Which the Alternatives Must Comply
• R307-I-2UAC
(Utah Air Conservation Rules-general requirement!)
• R307-1-3UAC
(Emission standards for control of installations)
• R307-1-4 UAC
(Emission standards)
• R307-10UAC
(Utah NESHAPs Standards)
• R307-12UAC
(Fugitive Dust Emission Standards)
• R307-I4UAC
ARAR
Ap
Ap
Ap
Ap
Ap
Ap
Type Will Alternative Meet ARAR? How Will It Comply?
A Yes - Prohibits emission of air contaminants in sufficient quantities to cause air pollution.
A, C Yes - Air emissions during remediation will be controlled to comply with air emissions
requirements; emission handled under existing IWTP permit.
A, C Yes • Air emissions during excavation would be controlled to comply with air emissions
requirements; emission handled under existing IWTP permit.
C Yes - Air emissions would be controlled to comply with this rule.
A Yes -Fugitive dust emissions generated during the IRA construction activities would be controlled
to meet the established fugitive dust emission standards.
A Yes -Air emissions would be controlled to comply with this rule.
Emission Standards for Ozone Non-Attainment Areas, Davis and Salt
Lake Counties)
• R315-2 UAC Ap
(General requirements - identification and listing of hazardous waste)
• R315-5 UAC Ap
(Hazardous waste generator requirements)
•R315-8-6UAC R
(Ground Water Protection Standards for Owners and Operators of
Hazardous Waste TSDFs)
• R317-1 UAC Ap
(Definition of water pollution rules and general requirements)
• R317-2 UAC Ap
(Standards for quality of waters of the State)
•R317-8 UAC Ap
(Utah pollution discharge elimination system)
• R655-4 UAC Ap
(Standards for drilling and abandonment of wells)
• 40 CFR Part 50 Ap
(Primary and secondary air quality standards)
• 40CFRPart61,Subpart A Ap
(NESHAPs Standards)
• 40 CFR Part 261 Ap
(Identification and listing of hazardous waste)
• 40 CFR Part 264. Subpart F Ap
(Requirements for detection and containment of releases)
A Yes - Determines potential waste classification and applicability of land disposal restrictions and
other solid and hazardous waste rules.
A Yes - Alternative will meet all requirements involving off-site handling and disposal of hazardous
waste.
A Yes - Complies with ground-water monitoring provisions.
C Yes • Ground water will be treated at the IWTP under the permit.
C Yes - Ground water will be treated under the existing IWTP permit.
A, C Yes- Ground water will be treated under the existing iWTP permit.
A Yes - Design of all extraction and monitoring wells will be in accordance lo this standard.
C Yes - Air emissions are expected to be well below established standards; emission handled under
existing IWTP permit.
C Yes - Ground water will be treated under the existing IWTP permit; emission handled under
existing IWTP permit.
C Yes - All hazardous waste will be classified according lo this ARAR.
Yes - This alternative will be implemented so that it complies with this ARAR.
ARAR
RCRA
TSDF
UAC
Applicable or relevant and appropriate requirement
Resource Conservation and Recovery Act
Applicable
Treatment, Storage, and Disposal Facility
Utah Administrative Code
A
L
R
C
Action-Specific ARAR
Location-Specific ARAR
Relevant and Appropriate
Chemical-Specific ARAR
-------
alternatives. For Alternatives 4 and 5, Hill AFB would need to contact the North Davis
County Sanitary District (NDCSD) and obtain a permit or permit modification to
discharge to the sanitary sewer.
In terms of waste handling, off-site regeneration of used carbon (Alternative 2) would
require compliance with hazardous waste manifesting regulations and the Federal and
State Department of Transportation hazardous materials regulations and hazardous waste
generator storage requirements.
One location-specific ARAR (R315-8-2.9) is applicable to implementing the OU8
interim action. In order to comply with this rule, it will be necessary to locate any new
treatment facilities outside areas considered to be a 100-year flood plain.
Short-Term Effectiveness. Alternatives 2 through 5 would be designed to protect
workers and the community during implementation of the remedial action. Worker
protection would be consistent with OSHA requirements in 29 CFR 1910.120, the OU 8
Health and Safety Plan, and the Contingency Plan (to be developed) during construction
and operation. The process tanks and pipelines would have secondary containment
systems with leak detection to identify and collect accidental spills or leakage. Emissions
from the air stripper (Alternatives 3 and 5) would be well below the health-risk based
standards and are not expected to pose a threat to the surrounding community or the
environment. Since no action would be taken at OU 8, Alternative 1 does not provide
any short-term effectiveness.
Long-Term Effectiveness. Alternatives 2 through 5 would prevent transport of
contaminants to off-Base areas and reduce potential impact to human health and the
environment. Operational information from these interim remedial systems would be
useful in evaluating the long-term effectiveness and permanence of a final remedy.
Alternative 1 delays any action until the final remedy is selected, so this alternative
would provide no long-term effectiveness nor permanence. Ground-water contamination
would migrate further off-Base, increasing the volume of contaminated ground water and
the subsequent cost of the final remedy.
Reduction of Toxicity, Mobility, and Volume Through Treatment at the
Site. Alternatives 2, 3 and 5 are expected to be equally effective in reducing the toxicity,
mobility, and volume of ground-water contaminants. The mobility of contaminants
would be reduced with Alternatives 2, 3, and 5 as the ground water is extracted; on-site
treatment would reduce the volume and toxicity of contaminants. These alternatives
would be designed to minimize further migration of contaminated ground water to off-
Base areas. For Alternative 4, the ground water is discharged directly to the sanitary
sewer without on-site treatment. The mobility of contaminants would be reduced using
an on-site extraction system. The toxicity and volume of contaminants would be reduced
off site as the ground water is treated at a POTW. Since Alternative 1 does not include
any treatment, this alternative would not reduce the toxicity, mobility, or volume of
contaminants at OU 8.
5-12
-------
Implementability. Alternative 1 would be the easiest to implement from a technical and
administrative standpoint as it only involves ground-water monitoring. Alternatives 2
through 5 would also be relatively easy to implement from a technical standpoint. The
necessary facilities for the ground-water extraction, treatment, and discharge systems are
commercially available, simple to construct, or already exist at Hill AFB. However,
Alternatives 4 and 5 would be simplest to construct, as only extraction wells and
discharge piping would need to be installed because the sanitary sewer (Alternative 4)
and the IWTP (Alternative 5) already exist. For Alternatives 2 and 3, new treatment
systems (Carbon Adsorption-Alternative 2; Air Stripper-Alternative 3) would need to be
installed in addition to extraction wells and discharge piping. For Alternatives 2
through 5, the ground-water extraction system and piping would have to traverse beneath
the south entrance to Hill AFB. These activities would require coordination with traffic
and minimizing any impact to underground utilities.
In terms of operation Alternatives 4 and 5 would be simplest to operate because both the
IWTP and NDCSD already exist, both operate under existing permits, both can easily
treat the contaminant concentrations present in OU 8 ground water, and preliminary
arrangements for the discharge of treated water via a permit modification have already
been made. The treatment systems under Alternatives 2 and 3 would be simple to
operate, but would require more direct oversight and sampling (i.e., increased operation
and management costs) to ensure that the systems are operating properly and that
contaminant concentrations are in compliance with the discharge standards.
Alternatives 4 and 5 have an implementability advantage over Alternatives 2 and 3,
because: (1) the treatment facilities (IWTP and NDCSD) already exist and a new
treatment system would not need to be constructed; (2) Hill AFB has an existing
agreement with the NDCSD for discharge to the sewer (which would need to be modified
to accept the discharge from this action); and (3) the IWTP is currently operating and
could easily treat the expected and potential contaminant concentrations in the extracted
water. Alternatives 2 and 3 are relatively low on the implementability scale as these
alternatives require installation of new treatment technologies and obtaining a permit for
discharge to a storm drain.
Costs. Alternative 1 is the least expensive of the five alternatives with a projected
present worth cost of $330,000. Among Alternatives 2 through 5, Alternative 4 has the
lowest present worth (approximately $1,385,000) and involves the least amount of capital
expenditure. Alternative 3 has the next lowest present worth (approximately
$1,481,000). The operational costs associated with Alternative 3 are less dependent on
changes in contaminant concentrations, but the capital costs are higher than for
Alternatives 4 and 5. The cost of Alternative 3 also could significantly increase if air
emissions controls are required in the future. Alternative 2 has slightly higher costs than
Alternative 3 and has a present worth cost of $1,552,000. However, the treatment cost
for this alternative is directly proportional to the mass of contaminants removed.
Therefore, an increase in contaminant concentrations could have a significant impact on
treatment costs. Alternative 5 has the highest present worth of all the alternatives
($1,764,000). However, if contaminant concentrations increased, the increase in costs for
Alternative 5 would be insignificant compared to the increase in costs associated with
5-13
-------
Alternatives 2, 3, and 4 because the IWTP is designed to treat concentrated wastes.
Additionally, Hill AFB believes that the costs associated with Alternative 5 are more
certain and that Hill AFB can more easily control these costs than for Alternatives 2, 3,
and 4.
State Acceptance. The State of Utah agrees with the preferred alternative
(Alternative 4).
Community Acceptance. All questions and concerns raised by the public were received
during an Open House on August 17, 1995. Alternative 5, with discharge to the IWTP
was presented as the preferred alternative. The primary concerns were related to health
effects of TCE and possible exposures, such as through wells, water in basement sumps,
and standing "wet areas" in Layton. Hill AFB's responses are summarized in the
Responsiveness Summary.
The public, in general, offered no opposition to the preferred alternative. However, one
community member expressed concerns over the cost-effectiveness of using the IWTP.
He expressed a preference for direct discharge to the sanitary sewer if it was available
(Alternative 4). Based on this, and additional information discussed in Section 6.3, Hill
AFB has reconsidered alternatives and is selecting Alternative 4 for the remedy for
interim action at OU 8.
5-14
-------
1
Section 6
-------
6.0 SELECTED REMEDY
6.1 DESCRIPTION OF THE SELECTED REMEDY
The selected remedy for an interim remedial action at Hill AFB OU 8 is Alternative 4 -
ground-water extraction and discharge to the sanitary sewer. Alternative 4 consists of
ground-water extraction using 8 vertical wells, and conveyance of extracted ground water
to the sanitary sewer and treatment at the POTW. If greater treatment efficiency, or ease
of implementability and cost effectiveness can be established at a later date, discharge of
extracted groundwater to the IWTP (Alternative 5) may again be considered.
Figure 6-1 shows the schedule for implementing the selected remedy. The first activities
will include design of the extraction wells and ground-water conveyance systems. The
design activities will be followed by the system construction and installation. Once the
system installation is complete, the individual components of the system and then the
entire system will be tested to ensure that the intent of the design was met during the
construction, and that the installed system is capable of meeting the performance
objectives. System testing will be followed by a start-up and prove-out period. The
entire system will then be operated and maintained until the final remedy is implemented.
Ground-water quality monitoring is scheduled on a quarterly basis during the initial stage
of the interim remedial action system. Ground-water monitoring will continue for the
duration of the interim remedial action, but the frequency of monitoring may be reduced
based on the observed trends in contaminant concentrations or migration. During this
interim action, the system performance will be reviewed to evaluate the effectiveness of
the system and to determine if it will be used as part of the final remedy at OU 8.
6.1.1. Remediation Objectives and Performance Standards
The interim action goals and objectives for OU 8 are to:
• Contain ground water at the southern boundary of Hill AFB to prevent
off-Base transport of contaminants above MCLs in the shallow ground water
and to reduce future potential off-Base risks
• Reduce the spread of contaminants, thereby controlling the volume and areal
extent of contaminated ground water at OU 8
• Reduce future cleanup costs by controlling the spread of contamination.
The area of attainment over which these cleanup goals are to be achieved is defined as the
area where ground-water contaminants exceed MCLs in a 600-foot wide section on the
west side of Hill Field Road and a 200-foot wide section on the east side of Hill Field
Road in the shallow aquifer along the southern boundary of the Base, as shown in
Figure 5-1. The extraction well design for the interim remedial action will be such that
the full horizontal and vertical extent of contamination exceeding MCLs (estimated to be
approximately 140 feet bgs) would be contained.
6-1
-------
PROJECT NO. 1166076.011801 12/12/95
YEARS
IlIlIUllllI Design phase
••• Construction or initiation phase
Implementation and operation phase
NOTE: Time zero'is defined as the beginning of substantial, continuous physical
improvement, which will begin not later than 15 months after this ROD is signed.
Hill AFB OU 8 ROD
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HILL AIR FORCE BASE
OPERABLE UNIT 8
CONCEPTUAL INTERIM REMEDIAL
ACTION IMPLEMENTATION SCHEDULE
FIGURE 6-1
-------
A performance and compliance sampling program (PCSP) will be implemented during
the remedial action to monitor performance and compliance with the RAOs. This
program will be developed during the implementation of the selected interim remedy and
will include locations of performance monitoring points, monitoring frequency, analytical
parameters, sampling and analytical methods, and statistical methods for evaluating data.
The PCSP will be designed to provide information to evaluate the effectiveness of the
interim remedial action. The PCSP will be included as part of the work plans developed
for this interim action, and will be reviewed and approved by Hill AFB, UDEQ, and EPA
regulators. The PCSP may be modified during the interim remedial action if site
conditions change.
6.1.2. Restoration Time Frame
Because this action is an interim solution designed only to contain the ground-water
contamination plume, a restoration time frame for cleaning up the ground water is not
applicable to this interim action. This interim system will operate until the final remedy
is implemented (expected to be within six years) and if it proves to be an effective
measure, it may be included as a component of the final remedy.
6.1.3. Costs
The total capital cost of the project is estimated at $750,000. The total capital cost
includes: installation of the extraction well network (approximately 8 wells), pumps,
conveyance piping to the sanitary sewer, and electrical and instrumentation components.
The indirect capital cost for the project is estimated at $220,000 and is included in the
estimated total capital cost cited above. Indirect costs include engineering, contingency,
and contract administration.
Operation and maintenance (O&M) costs over the duration of the interim remedial action
are calculated for a six-year period. Annual O&M is estimated at $135,000 per year.
O&M costs include power consumption, labor, well rehabilitation, regular maintenance,
sanitary sewer treatment charges, quarterly ground-water monitoring program, and
discharge water to the sanitary sewer. It was assumed that rehabilitation of each well will
occur once during the duration of this interim remedial action at an estimated cost of
$8,000 for 8 extraction wells. The total present worth cost of the selected interim remedy
over a six-year period, using an interest rate of ten percent, was estimated at $1,305,000.
These cost estimates should be accurate to within +50% to -30% of the actual cost.
During the implementation process for the selected alternative, modifications resulting
from the engineering design process could change the estimated costs for this alternative.
6.2 STATUTORY DETERMINATIONS
The selected interim action for Hill AFB OU 8 meets the statutory requirements of
CERCLA. These statutory requirements include protection of human health and the
environment, compliance with ARARs (within the scope of the IRA), cost effectiveness,
and utilization of permanent solutions and alternative treatment technologies to the
maximum extent practicable. Contaminant treatment is provided at the POTW. The
6-2
-------
manner in which the selected interim action for OU 8 meets each of the requirements is
presented in the following discussion.
6.2.1. Protection of Human Health and the Environment
The selected interim remedy for OU 8 is protective of human health and the environment.
The contaminated ground water currently migrating to off-Base areas contributes to a
future threat to human health and the environment. Implementation of the selected
interim remedy represents a preliminary step in achieving long-term protection by
preventing or minimizing transport of contaminants to off-Base areas.
6.2.2. Compliance with Applicable or Relevant and Appropriate Requirements
Section 121(d)(l) of CERCLA, as amended by SARA, requires that the interim remedial
action proposed for OU 8 must attain, to the extent practical under the selected interim
remedial action, a degree of cleanup that assures protection of human health and the
environment. In addition, remedial actions that leave any hazardous substances,
pollutants, or contaminants on the site must, upon completion, meet a level or standard
that at least attains legally applicable or relevant and appropriate standards, requirements,
limitations, or criteria that are applicable or relevant and appropriate requirements
(ARARs) under the circumstances of the release. ARARs include Federal standards,
requirements, criteria, and limitations and any promulgated standards, requirements,
criteria, or limitations under the State of Utah environmental or facility siting regulations
that are more stringent than Federal standards. In addition, the State of Utah ARARs
include all promulgated standards and rules associated with delegated State
environmental programs, and those State regulations with no corresponding Federal
regulations.
"Applicable" requirements are those cleanup standards, standards of control, and other
substantive environmental protection requirements, criteria, or limitations promulgated
under Federal or State law that specifically address the hazardous substances, pollutants,
or contaminants, remedial action, location, or other circumstance at the OU 8 site.
"Relevant and appropriate" requirements are cleanup standards, standards of control, and
other substantive environmental protection requirements, criteria, or limitations
promulgated under Federal or State law that, while not "applicable" to the hazardous
substance, pollutant or contaminant, remedial action, location, or other circumstance at a
remedial action site, address problems or situations sufficiently similar to those
encountered at the site that their use is well-suited to the particular site.
In evaluating which requirements are applicable or relevant and appropriate, the criteria
differ depending on whether the type of requirement is chemical-specific, action-specific,
or location-specific. According to the NCP, chemical-specific ARARs are usually health
or risk-based numerical values that establish the acceptable amount or concentration of a
chemical that may remain in, or be discharged to, the ambient environment. Action-
specific ARARs are usually technology or activity-based requirements or limitations on
actions taken with respect to hazardous wastes, or requirements to conduct certain actions
to address particular circumstances at the site. Location-specific ARARs generally are
6-3
-------
restrictions placed upon the concentration of hazardous substances or activities solely
because they are in special locations. Some examples of special locations include
floodplains, wetlands, historic places, and sensitive ecosystems or habitats.
The interim action selected for OU 8 will meet the ARARs that are applicable or relevant
and appropriate to this interim remedial action. Chemical- and action-specific ARARs
for the selected interim action are identified in Table 6-1. Federal and State location-
specific ARARs are not applicable nor relevant and appropriate to the OU 8 selected
interim remedy. A summary of ARARs to be met with alternate discharge options
(Alternative 5-IWTP) is presented in Table 6-2. The ARARs listed in Table 6-2 will be
applicable only if the IWTP discharge option is selected at a later date and if greater
treatment efficiency, cost effectiveness, or ease of implementation can be established for
an interim action at Operable Unit 8. Because the principal goal of this interim action is
hydraulic containment of ground water at the Base boundary, restoration of the
contaminated aquifer to drinking water standards is outside the scope of this interim
action. Aquifer restoration will be addressed during the selection of the final remedy for
all of OU 8. For this reason, regulations that address restoration of contaminated ground
water are not ARARs for this interim action. These ARARs include MCLs, the Utah
ground water quality standards, and the Safe Drinking Water Act
Discharge to the POTW will comply with the national pretreatment standards and limits
established by the POTW pretreatment program. Air emission requirements are met by
complying with the fugitive dust regulations and the air emissions requirements for the
Base air emissions permit. Hazardous waste generator and listing of hazardous waste
will comply with all requirements involving off-Base disposal of soils. The ground-water
protection rule will be met by complying with the ground-water monitoring provisions.
In addition, the design of all monitoring and extraction wells will be completed in
accordance to the appropriate drilling and completion standards.
Hill AFB obtained approval at a September 15, 1995, board meeting from the NDCSD to
increase the discharge to the sanitary sewer. Hill AFB also will complete amendments to
the "CERCLA Wastewater Discharge" clause to the existing utility contract before
initiating additional discharge to the sewer. All air quality and local discharge limits are
expected to be met with this alternative.
6.2.3. Cost Effectiveness
Overall cost effectiveness can be defined as the overall effectiveness proportionate to
cost, such that an action represents a reasonable value. The selected remedy for OU 8
will contain ground water at the Base boundary at a reasonable cost, thus providing
protection to human health and the environment. The selected interim action also has a
cost that is within the same range as the other action alternatives. If greater treatment
efficiency, cost effectiveness or ease of implementability can be established at a later
date, other discharge alternatives would be considered, such as the IWTP.
6-4
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TABLE 6-1
SUMMARY OF ARARs FOR THE SELECTED REMEDY
Alternative
ARARs With Which the Alternatives Must Comply
Alternative 4
(Discharge to Sanitary
Sewer)
R307-1-2UAC
(Utah Air Conservation Rules - general requirements)
R307-1-3UAC
(Emission standards for control of installations)
R307-1-4UAC
(Emission standards)
R307-1-4UAC
(Emission standards)
R307-10UAC
(Utah NESHAPs Standards)
R307-12UAC
(Fugitive Dust Emission Standards)
R307-14UAC
Emission Standards for Ozone Non-Attainment Areas, Davis and Salt Lake Counties)
R315-2UAC
(General requirements - identification and listing of hazardous waste)
R315-5UAC
(Hazardous waste generator requirements)
R315-8-6 UAC
(Ground Water Protection Standards for Owners and Operators of Hazardous Waste
TSDFs)
R317-1 UAC
(Definitions for water pollution rules and general requirements)
R317-2 UAC
(Standards for quality of waters of the State)
R317-6 UAC
(Ground-water quality protection rule)
R317-8 UAC
(Utah pollution discharge elimination system)
R655-4 UAC
(Standards for drilling and abandonment of wells)
40 CFR Parts 122-125
(National pollution discharge elimination System)
40 CFR Part 264, Subpart F
(Requirements for detection and containment of releases)
40-CFR Part 270
(Hazardous waste permit program)
40 CFR Part 403
(National pretreatment standards)
ARAR Applicable or relevant and appropriate requirement
CFR Code of Federal Regulations
RCRA Resource Conservation and Recovery Act
TSDF Treatment, storage, and disposal facility
UAC Utah Administrative Code
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TABLE 6-2
SUMMARY OF ARARs FOR THE OPTIONAL REMEDY
Alternative
ARARs With Which the Alternatives Must Comply
Alternative 5
(Treatment at IWTP and
Discharge to Sanitary Sewer)
R307-1-2UAC
(Utah Air Conservation Rules-general requirements)
R307-1-3UAC
(Emission standards for control of installations)
R307-1-4 UAC
(Emission standards)
R307-10 UAC
(Utah NESHAPs Standards)
R307-12 UAC
(Fugitive Dust Emission Standards)
R307-14 UAC
Emission Standards for Ozone Non-Attainment Areas, Davis and Salt Lake Counties)
R315-2 UAC
(General requirements - identification and listing of hazardous waste)
R315-5 UAC
(Hazardous waste generator requirements)
R315-8-6 UAC
(Ground Water Protection Standards for Owners and Operators of Hazardous Waste TSDFs)
R317-1 UAC
(Definition of water pollution rules and general requirements)
R317-2 UAC
(Standards for quality of waters of the State)
R317-8 UAC
(Utah pollution discharge elimination system)
R655-4 UAC
(Standards for drilling and abandonment of wells)
40 CFR Part 50
(Primary and secondary air quality standards)
40CFRPart61,SubpartA
(NESHAPs Standards)
40 CFR Part 261
(Identification and listing of hazardous waste)
40 CFR Part 264, Subpart F
(Requirements for detection and containment of releases)
ARAR Applicable or relevant and appropriate requirement
CFR Code of Federal Regulations
RCRA Resource Conservation and Recovery Act
TSDF Treatment, storage, and disposal facility
UAC Utah Administrative Code
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6.2.4. Utilization of Permanent Solutions and Treatment Alternative Technologies
or Resource Recovery Technologies to the Maximum Extent Practical
The selected remedy for OU 8 does not provide on-site treatment; however, extracted
ground water will be treated at the POTW. Hence, the selected remedy for OU 8 utilizes
permanent solutions to the maximum extent practical. The statutory preference for
treatment as a principal element for ground water as a whole will be addressed in the final
Record of Decision for OU 8. However, this remedy is only an interim measure and its
effectiveness will be evaluated in the final decision document for OU 8. If greater
treatment efficiency or cost effectiveness can be established at a later date, discharge of
extracted groundwater to the IWTP (Alternative 5) may again be considered.
The selected interim action provides the best balance of tradeoffs among all the
alternatives with respect to the five summary balancing criteria which include:
• Long-term effectiveness and permanence
• Reduction of toxicity, mobility, or volume through treatment
• Short-term effectiveness
• Implementability
• Cost.
The criterion most critical in the selection of this remedy was implementability.
Alternative 4 will be easy to implement because it will utilize direct discharge to a
sanitary sewer, which eliminates the need for constructing an additional treatment
facility. To an extent, this alternative is not affected by the changing site conditions
(e.g., a decrease in contaminant concentrations). The modifying criteria, which are State
and community acceptance, have had an effect on selection of the remedy. The State
agrees with the selected remedy. However, one of the community members had
expressed cost concerns over selection of Alternative 5 as the preferred remedy. Given
additional information suggesting the zone to be contained is smaller with lower
concentrations. Hill AFB now concurs with the community member. Hill AFB has,
therefore, selected Alternative 4 as the remedy for an interim action at OU 8.
6.3 DOCUMENTATION OF SIGNIFICANT CHANGES
The Proposed Plan for an interim action at Hill AFB OU 8 (Montgomery Watson, 1995c)
was released for public comment in July 1995. The Proposed Plan identified
Alternative 5 - ground-water extraction, treatment at IWTP, and discharge to a sanitary
sewer as the preferred alternative; one modification to the Proposed Plan was made and
included eliminating carbon treatment of air emissions. This change was necessary to
make this alternative consistent with the current operations at the IWTP.
Further investigation work has been conducted since the Proposed Plan for OU 8 IRA
was released. The recent fieldwork focused on further delineation of the contaminant
plume and definition of aquifer characteristics along the southern Base boundary. This
investigation included CPT (13 locations, 130 to 200 feet bgs) and hydropunch sampling
(13 locations at 3 to 5 depths at each location), installation and sampling of monitoring
6-7
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wells (5 wells), installation of three ground-water extraction wells and piezometers, and
the performance of three constant pump rate aquifer tests.
The results of this field investigation indicate that the extent of the contaminant plume is
not as extensive as suggested by previous investigations. This has resulted in a much
smaller area of attainment. The horizontal extent of the contaminant plume is now
believed to extend approximately 800 feet along the Southern Base Boundary, compared
to approximately 2,000 feet as indicated in the previous documents. Further, the
concentrations of contaminants detected in the OU 8 area are lower than previously
understood.
Results of the recent investigation have made Alternative 4 more feasible, both
technically and economically. The chances of discharge from the IRA system exceeding
the NDCSD discharge permit levels have been reduced significantly. Reduced
contaminant loading from the IRA discharge would lower the discharge fee to be levied
by the NDCSD. In addition, the smaller horizontal extent of contamination means fewer
extraction wells and, thus, less volume of extracted ground water. This will further
reduce the cost associated with direct discharge to a POTW.
Written and verbal comments received during the public comment period expressed
concerns over the cost effectiveness of Alternative 5 and discharge to the IWTP.
Hill AFB agrees with the comment. Changing the preferred remedy for the OU 8 IRA to
Alternative 4 addresses those concerns. A copy of the proceedings of the Proposed Plan
open house, as well as the comments received, are included as Appendices A and B,
respectively.
Selection of Alternative 4 as the preferred remedy does not change the principal element
of remedy for the IRA—containment of ground water at the Base boundary of Hill AFB
to prevent off-Base transport of contaminants above MCLs. However, Alternative 4
relies on off-site treatment (POTW) to reduce the volume and toxicity of the ground-
water contaminants.
The selected remedy for an interim action for Operable Unit 8 is Alternative 4—Ground-
Water Extraction and Discharge to Sanitary Sewer. The EPA and UDEQ concur with the
selected remedy. If greater treatment efficiency, cost effectiveness or ease of
implementability can be established at a later date, discharge of extracted groundwater to
the IWTP (Alternative 5) may again be considered.
6-8
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Hill Air Force Base, Utah
Operable Unit 8
Responsiveness Summary
-------
Overview
This responsiveness summary provides information about the views of the community
with regard to the proposed interim remedial action for Hill AFB OU 8, documents how
public comments have been considered during the decision making process, and provides
responses to concerns.
The public was informed of the selected remedial action in the following ways:
• All items contained within the Administrative Record have been on file at the
subject repositories since the final version of each document was issued.
• A copy of the Proposed Plan was sent to all affected and interested parties
prior to the public comment period.
• A public comment period was held from August 8, 1995, through
September 7,1995.
• Three thousand flyers were sent to area residences announcing the public
Open House.
• A public Open House was held on August 17, 1995, at Northridge High
School, Layton, Utah.
• Written comments by the public were encouraged.
The public Open House was well attended, and residents provided written concerns about
the proposed action. A copy of the written comments received at the public meeting is
attached as Appendix B. As indicated in the Record of Decision, one community
member expressed cost concerns over selection of Alternative 5 as the preferred remedy.
After further consideration, Hill AFB agrees with the community member and has
selected Alternative 4 as the preferred remedy. No verbal comments were received by
the court reporter during the Open House. The transcript of the Open House is presented
in Appendix A.
Background on Community Involvement
The public participation requirements of CERCLA Sections 113(k)(2)(B)(i-v) and 117
were met. Hill AFB has a Community Relations Plan (Hill AFB, 1992) that is revised as
necessary. The community relations activities include: (1) a Restoration Advisory Board
(RAB), which meets regularly and includes community representatives from adjacent
counties and towns, (2) a mailing list for interested parties in the community, (3) a
bi-monthly newsletter called "EnviroNews," (4) visits to nearby schools to discuss
environmental issues, (5) community involvement in a noise abatement program,
(6) presentations and updates are given at semi-annual town council meetings,
(7) opportunities for public comment on remedial actions, (8) community interviews, and
(9) support for the community in obtaining technical assistance grants (TAGs).
The Focused FS Report for OU 8 (Montgomery Watson, 1995b), and the Proposed Plan
for OU 8 (Montgomery Watson, 1995c) were released to the public, and are available in
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the Administrative Record maintained at the Davis County Library and at the
Environmental Management Directorate at Hill AFB. The notices of availability for
these documents were published in the Salt Lake Tribune, Ogden Standard Examiner, and
Hilltop Times. A public comment period was held from August 8, 1995, through
September 7, 1995. In addition, a public Open House was held on August 17, 1995.
At this meeting, representatives from Hill AFB, EPA, and the State of Utah answered
questions about the site and the selected remedy. A court reporter was present to record
formal verbal comments or questions, but none were received. Copies of the transcript
and all written public comments received during the comment period have been placed in
the Administrative Record. Responses to the comments received during the public
comment period are included in this Responsiveness Summary, which is part of the ROD.
The decision process for this site is based on the Administrative Record.
Summary of Public Comments and Agency Responses
Part I - Summary and Response to Local Community Concerns. The community
comments and concerns are discussed in the following sections.
Economics of Treatment Method
One community member expressed his concern that he was not sure that using the
existing treatment facility at the IWTP was the most economical method for treating the
extracted ground water. The community member was told that the use of the existing
facility provides some advantages in terms of implementing the alternative because:
• Hill AFB would not need to construct a new treatment system
• Hill AFB has an existing agreement with the NDCSD for discharge to the
sewer
• Hill AFB currently operates the IWTP, and the facility can easily treat the
expected and potential contaminant concentrations.
The community member was also told that the costs associated with using the IWTP are
relatively close to the estimated costs for other treatment methods, but can be more easily
controlled than for other alternatives.
However, recent investigations indicate that the areal extent of the contaminant plume at
the southern Base boundary is not as extensive as previously suggested. Further, the
concentration of contaminants are lower than previously understood. These factors make
Alternative 4 more feasible, both technically and economically. Consequently, Hill AFB
concurs with the concern expressed by the community member and proposes to select
Alternative 4 as the preferred remedy for an interim action at Operable Unit 8.
-2-
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Alternative Implementation
One community member expressed concern that the current regulatory environment will
eventually lead to cleanup of the site even if this proposed action does not happen, which
will then end up costing more. The community member then stated that the proposed
interim action should take place, even if the risks are minimal, because it will save money
over the long term. The community member was told that Hill AFB plans to implement
the interim action as presented in the Proposed Plan and that the community did not raise
any objections to the proposed action. Consequently, there currently are no obstacles to
implementing this alternative.
General Concerns
One community member indicated that she knew of, within a one-block radius of her
house, six cases of Type n diabetes. The community member was told that diabetes is
not a symptom of exposure to the chemicals of concern for OU 8 and was sent
information regarding TCE exposure.
Two community members expressed their satisfaction with the Open House and
Proposed Plan and with Hill AFB's response to their concerns. No response was
necessary.
Part II - Comprehensive Response to Specific Legal and Technical Questions
No specific legal and technical questions were raised by the community.
Remaining Concerns
Several concerns, questions, and requests were raised by community members to
Hill AFB personnel informally during the Open House and by telephone during the
public comment period. These concerns, and Hill AFB's responses, are summarized
below:
One community member requested a copy of a report that provides contamination levels
of ground water beneath his property in Layton. Hill AFB provided these results to the
community member.
A community member indicated that he knew of a well north of his property that is being
used, and he provided his address to Hill AFB. This community member also requested
information regarding the long-term effects of TCE exposure at high concentrations
because he had worked in a shop area for many years; he also indicated that he has some
health problems. The community member was contacted to obtain more information
about the well, which was found to be used for irrigation and stock watering.
The community member was told that the use of the well would be investigated further
during the RI for OU 8. Regarding TCE exposure, the community member was referred
to the Occupational Health Office at Hill AFB to obtain more information regarding his
concern.
-3-
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One community member requested a copy of the Proposed Plan as well as drinking water
MCLs for contaminants. These materials were mailed to the community member.
A community member indicated that he smelled a strong, mold-like odor between Hill
Field Road and Fort Lane and requested that Hill AFB investigate the smell. Hill AFB
contacted the Davis County Health Department, who then visited the site to check out the
odor. The Davis County Health Department personnel did not smell the odor at the
indicated location. The community member was contacted and told that the smell was
likely due to an agricultural or irrigation source and that he should notify the Health
Department if he smells the odor again.
Three community members reported standing water near their homes, of which one
member indicated that he had a wet basement. Hill AFB personnel visited the site and
observed wet areas near some of the property owners. One soil and two ground-water
samples were taken and analyzed for volatile organic compounds. The soil sample was
clean, but both water samples contained low levels of TCE (<10 |ig/l). Hill AFB
personnel contacted the landowners and explained these results and indicated that the
concentrations observed did not represent a health concern. Hill AFB personnel also
visited the site with personnel from the city of Layton and the U.S. Army Corps of
Engineers to evaluate the potential for wetlands. While on site, this group met with
landowners and discussed the contamination at the site, indicating that the contamination
does not represent a health threat and will be investigated further during the RI.
A Layton resident called Hill AFB and reported that she has a wet spot in her yard and
has had drainage problems since the Mitchell Plaza was developed several years ago.
She indicated that she just wanted to call to let us know about this. No response was
necessary. She will be contacted during the RI.
Another resident called Hill AFB, indicating that her children eat a lot of soil. She was
told that no current risk from soil exists as far as contaminants from Hill AFB and that
ground water is the medium of concern for OU 8. Hill AFB also confirmed with the
resident that there are no wet spots in her yard.
A community member called Hill AFB to request information regarding the health effects
of TCE exposure. She indicated that she grew up near the present location of Layton
Hills Mall and that she is currently suffering from a list of health problems ranging from
an enlarged liver to dizziness. She indicated that the neighborhood obtained its water
from a local well near the present location of the Sizzler restaurant. She further stated
that the well was tested by the city and found to contain oil and other unidentified
constituents that she says were from Hill AFB. She was told that Hill AFB was planning
additional investigative work in the area, but it was unlikely the well contained
contaminant concentrations that would produce the reported health effects. None of the
surrounding wells show signs of contamination. Other health problems like she
described have not been reported to the Health Department. Neither Hill AFB, the City
of Layton, nor Davis County Health Department were aware of the well, nor the sampling
results she referenced.
-4-
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One community resident telephoned Hill AFB and reported that she was concerned about
contamination, particularly with respect to her garden. The community member was told
that, based on the available data, there shouldn't be any health effects from the
contamination. She was also told that the area where she lives is drained by field drains
that transport the water away from her housing development. Hill AFB also sent her the
Proposed Plan for the interim action.
-5-
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Hill Air Force Base, Utah
Operable Unit 8
References
-------
REFERENCES
Battelle, 1994. UST Site 280 Final Report on Bioremediation of Hazardous Wastes at
CERCLA and RCRA Sites: Hill APB 280 Site Low Intensity Bioreclamation.
Chen-Northern 1989. Pond 3 Site Evaluation Report, Hill Air Force Base, Ogden, Utah.
Prepared for Hill Air Force Base, September 1989.
Environmental Science and Engineering (ESE) 1989a. Data Compilation Report RJ/FS
Berman Pond and Building 514 Area, March 1989.
Environmental Science and Engineers, Inc., (ESE) 1989b. Layton Groundwater
Investigation, March 1989.
Feth, J.H., D.A. Barker, L.G. Moore, R.J. Brown, and C.E. Veirs, 1966. Lake
Bonneville: Geology and Hydrology of the Weber Delta District including Ogden,
Utah. U.S. Geological Survey Professional Paper 518.
Hill Air Force Base, 1992. Installation Restoration Program Environmental Community
Relations Plan, February, 1992.
Hill Air Force Base, 1984. Hill Air Force Base Civil Engineers Sodium Hydroxide Tank
Site Investigation, (Unpublished data).
James M. Montgomery, Consulting Engineers, Inc. (JMM), 1989a. Summary of Site
Characterization Data Collected During 1988 in the IWTP Area, Hill AFB, Utah,
March 1989.
James M. Montgomery, Consulting Engineers, Inc. (JMM), 1989b. Internal Draft
Remedial Investigation Report for Operable Unit 3 at Hill Air Force Base, Utah,
July 1989.
James M. Montgomery, Consulting Engineers, Inc. (JMM), 1992a. Draft Final Remedial
Investigation Report for Operable Unit 3 at Hill Air Force Base, Utah, April 1992.
James M. Montgomery, Consulting Engineers, Inc. (JMM), 1992b. Final Subsurface
Report for UST Site 204.1, Hill Air Force Base, Utah, December 1992.
James M. Montgomery, Consulting Engineers, Inc. (JMM), 1992c. Draft Final
Corrective Action Plan for UST Site 22, Hill Air Force Base, Utah, November.
1992.
James M. Montgomery, Consulting Engineers, Inc. (JMM), 1992d. Final Abatement and
Initial Site Characterization Report for UST Site 236, Hill Air Force Base, Utah,
July 1992.
R-l
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Montgomery Watson, 1994a. Draft Final Environmental Assessment for Operable
Unit 8, Hill Air Force Base, Utah, December 1994.
Montgomery Watson, 1994b. Draft Final Remedial Investigation Report Addendum for
Operable Unit 3, Hill Air Force Base, Utah.
Montgomery Watson, 1994c. Draft Subsurface Characterization Report, Corrective
Action Plan, and Free Product Removal Report for UST Site 260, Hill Air Force
Base, Utah, June 1994.
Montgomery Watson, 1995a. Final Data Summary and Recommendations Report for
Operable Unit 8, Hill Air Force Base, Utah, January 1995.
Montgomery Watson, 1995b. Final Interim Remedial Action Focused Feasibility Study
for Base Boundary, Operable Unit 8, Hill Air Force Base, Utah, August 1995.
Montgomery Watson, 1995c. Final Proposed Plan for Operable Unit 8, Hill Air Force
Base, Utah, August 1995.
Montgomery Watson, 1995d. Final First and Second Monitoring Rounds Data Evaluation
for Operable Unit 8, Hill Air Force Base, Utah, March 1995.
Montgomery Watson, 1995e. Final RI/FS Report for OU 7, Hill Air Force Base Utah,
February 1995.
Montgomery Watson, 1995f. Final RI/FS Work Plans for OU 8, Hill Air Force Base,
Utah, June 1995.
Montgomery Watson, 1996a. OU 8 Off-Base Drainage Survey, Water User Survey, and
Residential Survey Letter Report, Hill Air Force Base, Utah, December 1996.
Montgomery Watson, 1996b. Interim Remedial Action Field Work Data Summary and
Remedial Design Technical Memorandum for Operable Unit 8, Hill Air Force
Base, Utah, March 1996.
Radian Corporation, 1988a. Installation Restoration Program Phase II, Stage 2, Hill Air
Force Base, Utah, July 1988.
Radian Corporation, 1988b. Installation Restoration Program Phase II -
Confirmation/Quantification Stage I Building 220, Paint Hangar, Prepared for
Hill Air Force Base, Utah, May 1988.
Radian, 1989. Pond 2 Investigation, (Unpublished data).
Sergeant, Hauskins and Beckwith (SHE), 1985. Field Soil Boring Logs and Sketch Maps
for a Site Investigation at the IWTP Sludge Drying Beds, Hill Air Force Base,
Utah.
R-2
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UBTL, Inc., 1984, Hill AFB, Utah. Installation Restoration Program Phase IB Survey,
Final Report, September 1984.
United States Geological Survey (USGS), 1992. Final RI Report for Operable Unit 4.
Prepared for U.S. Air Force Logistics Command, September 1992.
R-3
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PUBLIC MEETING TRANSCRIPT
Appendix A
-------
APPENDIX A
PUBLIC MEETING TRANSCRIPT
The public meeting transcript is attached as Appendix A.
A-l
-------
1 REPORTER'S STATEMENT
2
I, Shirlyn Sharpe, Certified Shorthand Reporter and
Notary Public for the State of Utah, do hereby state;
That I attended the public meeting for the Public Open
House for Operable Unit 8 at Hill Air Force Base held at
Northridge High School, Hill Air Force Base Road, Layton,
8 Utah on Augusc 17, 1995, from 4:00 p.m. to 9:00 p.m.;
That I was available to record any comments from the
10 attendees there present;
Thac no one appeared before me to make any such public
12 comment or statement.
13
14
15
16| Shirlyn Sharpe, CSR, CMR
17
18
19
20
21
22
23
24
25
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WRITTEN COMMENTS AND RESPONSES
Appendix B
-------
APPENDIX B
WRITTEN COMMENTS AND RESPONSES
The submittal of written comments from community members was requested at the
public Open House and during the public comment period. Forms asking specific
questions regarding the Open House format, the RI/FS process, and the preferred
alternatives were available at the public Open House, and attendees were encouraged to
respond. The following comments were received; where appropriate, Hill AFB's
responses are also included.
B-l
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COMMENTS RECEIVED FROM ANONYMOUS COMMUNITY MEMBER
(See pages following this cover page)
HILL AFB RESPONSE
1. Economics of Treatment Method. Hill AFB screened all available technologies for
treating the ground water removed by the proposed hydraulic containment system.
Alternative 5, although having the highest cost of the five alternatives, is still within the
cost ranges estimated for the other three alternatives involving ground water extraction
and treatment. Further, use of the existing system provides advantages for the following
reasons:
• Hill AFB would not need to construct a new treatment system
• Hill AFB has an existing agreement with the NDCSD for discharge to the
sewer
• Hill AFB currently operates the IWTP, and the facility can easily treat the
expected and potential contaminant concentrations.
Additionally, if contaminant concentrations in the extracted ground water increase, the
costs associated with Alternatives 2, 3, and 4 would increase significantly, while costs for
Alternative 5 would remain essentially the same because the IWTP at Hill AFB is
designed to treat highly concentrated wastes.
2. Alternative Implementation. Hill AFB intends to implement the proposed action
and agrees that no action now will result in increased costs later due to spread of the
contamination. Based on public comments, community members were not against
implementing the proposed action. Consequently, there currently are no obstacles to
implementing this action as planned.
B-2
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What do you think?
i
j .u. _*i~ Augun IT, 1995 j
Preferred Alternative _ _3 _ |
Background
An interim containment action has been proposed by Hill AFB to stop the flow of contaminated groundwater from
Hill AFB into Layton. The Air Force, Environmental Protection Agency and Utah Department of Environmental
Quality have agreed that some kind of containment action at die base boundary would be prudent. Therefore. Hill
AFB has proposed die Prefer red Interim Containment Alternative, which is oudined in die Proposed Plan.
According to die preferred alternative, Hill AFB will install a series of extraction wells along die base boundary.
These weUs will remove contaminated groundwater from die area and will prevent contaminated groundwater north
of die base boundary from moving off base in die future. The extracted groundwater will be treated at die bases
industrial wastewater treatment plant and discharged into die local sewer system for further treatment.
nark Uw appnprtate response. Use opposite sUo for writing commits, H decenary)
Overall, does Hill's proposal to contain contaminated groundwater at the base boundary meet your expectations
or address your concerns?
I Yes I^J No l^J Nor sure
If you answered "No" or "Not sure," please explain.
Are you satisfied with the use of extraction wells to remove contaminated groundwater?
1 2 (£^. 4 5
Very Satisfied Not Satisfied
If you chose 4 or 5, please explain why. ^S' r*- "^ tfctW^ «'
Are you satisfied widi the method of treating the extracted groundwater, ie. using
-------
What do you
Preferred Alternative-page 2
Is there anything else about the proposed Interim Containment Action that concerns you?
-rL.T~ -r^ rf>*u/*T*r*' <°'M.-'.~S~w*?«*t~ tW r, .'nJ&- le^s rr
Hill is in the process of conducting a detailed investigation in this area. If you have any information that you
think may be helpful to us, please either write it down here or write your name and phone number so we can
contact you later. Any information is greatly appreciated.
Additional thoughts
-------
What do you
. ... _^ August IT. 199>
Preferred Alternative !
Background
An interim containment action has been proposed by Hill AFB to stop the flow of contaminated groundwater from
Hill AFB into Layton. The Air Force, Environmental Protection Agency and Utah Department of Environmental
Quality have agreed that some kind of containment action at me base boundary would be prudent. Therefore. Hill
AFB has proposed the Preferred Interim Containment Alternative, which is outlined in die Proposed Plan.
According to the preferred alternative. Hill AFB will install a series of extraction wells along the base boundary.
These wells will remove contaminated groundwater from the area and will prevent contaminated groundwater north
of die base boundary from moving off base in the future. The extracted groundwarsr will be orated a; rh: base'*
industrial wastewater treatment plant and discharged into die local sewer system for further treatment.
Qll6StJOnS (Please nark the appropriate response. Use opposite side for writing comments. It necessary)
Overall, does Hill's proposal to contain contaminated groundwater at the base boundary meet your expectations
or address our concerns?
O QNotsure
If you answered "No" or "Not sure," please explain.
Are you satisfied with the use of extraction wells to remove contaminated groundwater?
^P 23 4 5
Very Satisfied ___ 7 /' Tr^/' J2^ ~iAr-rs.i**J Not Satisfied
If you chose 4 or 5, please explain why..
Are you satisfied with die method of treating the extracted groundwater, ie. using existing facilities at the base's
Industrial Wastewater Treatment Plant?
2345
^ '
Ven- Satisfied £^f-- ^J1- ^M^.6L—^Z~
-------
What do you think?
Preferred Alternative-page 2
Is chert anything else about the proposed Interim Containment Action that concerns you?
III!! is in the process of conducting i CKaiir-1 imssugatinr. ir. this arsn. !f you-Have any information that vou
think may be helpful to us, please either write it down here or write your name and phone number so we can
contact you later. Any information is greatly appreciated.
Additional thoughts
-------
What do you
August 1~. 1995
Hill Air Force Base Operable Unit 8 Open House
Thank you for attending tonight's Open House. Its purpose is to present the proposed Interim Action at "Operable
Unit 8" at Hill AFB and to hear your comments. We have designed this meeting to be informal, which allows you
to move about the room freely, visiting any or all of the stations at your convenience.
As you may have noticed, we have set up several poster stations. Each station presents information on a different
topic. Experts are present at each station to answer your discuss your concerns or answer your questions. We encour-
age you to visit all the stations and carefully review the posters. Copies of the posters are also available as handouts.
if you wish to review the information at a later time.
Please be sure to fill out these two sheets before you leave tonight. You may leave them in the white box at the
Comment Station. If you wish to £U :hs:r. ou: later, you may mail them to the following address:
Ms. Gwen Brewer
Environmental Public Affairs Coordinator
00-ALC/EM
7274 Wardtigh Road
Hill AFB. UT 84056-5137
Be sure it is postmarked no later than Sept. 7, 1995-
If you would rather express your comments or concerns verbally, a recorder is present to transcribe what you have to
sav.
Printed name (optional):
Al ^r 4 Cr*
How did you learn of tonights Open House?
\ \ Newspaper ads l_J| Flyer £^ Proposed Plan mailing l_J Radio Announcement
LJ Word of mouth LJ Other _ ; _ _ _________
Did you like the way the Open House was organized? ^J *es
Do you have any suggestions to improve future meetings? If so, please explain.
y .^•>-?.
/
Are there any other groups, companies or individuals you feel should be sent information about the cleanup
effort at Hill AFB? (Please provide names and addresses, if possible)
Name: Name:
Address: . ; Address:
City, State ZIP:___ Gty, State ZIP:.
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Additional thoughts?
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COMMENTS RECEIVED FROM MS. JENE W. SMITH
(See pages following this cover page)
HILL AFB'S RESPONSE
1. Health Concerns (Diabetes). Diabetes is not a symptom of exposure to the
chemicals found in OU 8 ground water.
B-3
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What do you think?
Hill Air Force Base Operable Unit 8 Open House gust
Thank you for attending tonights Open House. Its purpose is to present the proposed Interim Action at "Operable
Unit 8" at Hill AFB and to hear your comments. We have designed this meeting to be informal, which allows you
to move about the room freely, visiting any or all of the stations at your convenience.
As you may have noticed, we have set up several poster stations. Each station presents information on a different
topic. Experts are present at each station to answer your discuss your concerns or answer your questions. We encour-
age you to visit all the stations and carefully review the posters. Copies of the posters are also available as handouts,
if you wish to review the information at a later time.
Please be sure to fill out these rwo sheets before you leave tonight. You may leave them in the white box at the
Comment Station. If you wish to nii them out later, you may mail them to the following address:
'
Environmental Public Affairs Coordinator
OO-ALOEM
7274 Wardltigh Rood
Hill AFB. UT 84056-5 137
Be sure it is postmarked no later than Sept. 7, 1995.
If you would rather express your comments or concerns verbally, a recorder is present to transcribe what you have to
say.
Printed nam, faprinnatt: l /,
U^^-
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Additional thoughts?
°L /•
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DEPARTMENT OF THE AIR FORCE
HEADQUARTERS OGOEN AIR LOGISTICS CENTER (AFMC)
HILL AIR FORCE BASE, UTAH
September 5. 1995
Ms. Jene' W. Smith
1708 K. Alder
Lay ton UT 84041
Dear Ms. Smith
I received your comment sheet from the Open House. We appreciate the
feedback. After checking with the medical people on base and the Utah
Department of Environmental Quality, we found no known evidence that
diabetes results from exposure to the solvent Trichloroethylene (TCE).
Enclosed is a lexicological profile about TCE from the Agency for Toxic
Substances and Disease Registry (ATSDR). ATSDR was delegated by
Congress to monitor Superfund health issues. The profile includes the phone
number and address at the agency.
The Layton investigation is in preliminary stages. Any information you
have may speed the process. Please call Howie Aubertin or me with further
concerns or questions.
Sincerely
GWEN BREWER
Environmental Public Affairs
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COMMENTS RECEIVED FROM MS. MYRLE CROWN
(See pages following this cover page)
HILL AFB'S RESPONSE
None Required.
B-4
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What do you think?
August 17. 199^
Hill Air Force Base Operable Unit 8 Open House
Thank you for attending tonights Open House. Its purpose is to present the proposed Interim Action at "Operable
Unit 8" at Hill AFB and to hear your comments. We have designed this meeting to be informal, which allows you
to move about the room freely, visiting any or all of the stations at your convenience.
As you may have noticed, we have set up several poster stations. Each station presents information on a different
topic. Experts are present at each station to answer your j*p*"*« your concerns or answer your questions. We encour-
age you to visit all the stations and carefully review the posters. Copies of the posters are also available as handouts.
if you wish to review the information at a later time.
Please be sure to fill out these two sheets before you leave tonight. You may leave them in the white box at the
Comment Station. If you wish to fill them out later, you may mail them to the following address:
Mi. Gwen Brewer
Environmental Public Affairs Coordinator
OO-ALOEM
7274 WardUigh Road
Hill AFB. UT 84056-5137
Be sure it is postmarked no later than Sept. 7, 1995.
If you would rather express your comments or concerns verbally, a recorder is present to transcribe what you have to
sav.
Printed name (optional):
>
How did you learn of tonight's Open House?
Newspaper ads J^J Flyer IJ Proposed Plan mailing IJ Radio Announcement
Word of mouth Other _
Did you like the way the Open House was organiied?
Do youjiave any suggestions to improve future meetings? If so, please explain.
_fg -£c
U
_ -,, / / t
Are there any other groups, companies or individuals you feel should be sent information about the cleanup
effort at Hill AFB? (Please provide names and addresses, if possible)
Name: ______________________ Name: -
Address: _ Address:
Gry, State ZIP: __ Gty, State ZIP:
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Additional thoughts?
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COMMENTS RECEIVED FROM MR. SCOTT PAXMAN
(See pages following this cover page)
HELL AFB'S RESPONSE
None Required.
B-5
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