EPA/ROD/R10-94/083
                                November 1994
EPA  Superfund
       Record of Decision:
       Elmendorf Air Force Base,
       (O.U. 1), Anchorage, AK,

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UNITED STATES AIR FORCE
ELMENDORF AIR FORCE BASE, ALASKA
, ENVIRONMENTAL RESTORATION PROGRAM
RECORD OF DECISION -- FINAL
OPERABLE UNIT 1

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CONTENTS
PAGE
ACRONYMS AND ABBREVIATIONS. . . . . . . .-. . . . . . . . . . . . . . .. 5
1.0
DECLARATION OF THE RECORD OF DECISION
Site Name and Location............................
1.1
1.2
1.3
1.4
1.5
1.6
Statement of Basis and Purpose.... ..........
Assessment of the Site...'...................
Description of the Selected Remedy..........
Statutory Determinations .............. "'"
Lead and Support Agency Acceptance of the
Record of Decision.................... . . . . . . 9 -11
2.0
DECISION SUMMARY
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
Site Name, Location, and Description........
Site History and Enforcement Activities.....
Highlights of Community Participation.......
Scope and Role of Operable Unit.............
Site Characteristics........................
2.5.1
2.5.2
Geology & Hydrogeology........ .....
Nature and extent of
Contamination. . . . . . . . . . . . . . . . . . . . . .
Summary of Site Risks..................... . .
2.6.1
2.6.2
Human Health Risks.................
Uncertainties Associated
With Risk Assessment............ ...
2.6.3
Environmental Evaluation...........
Description of Alternatives.................
2.7.1
2.7.2
Remedial Action Objectives...... ...
Remedial Alternatives........... ...
Alternative 1: No Action
'Alternative 2: No Action
, With Long Term Monitoring
Alternative 3: In Situ
Treatment of Groundwater
Summary of Comparative Analysis

of Al t e rna t i ves. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.8.1
2.8.2
2.8.3
Threshold Cri teria. . . . . . . . . . . . . . . . .
Primary Balancing Criteria.........
Modifying, Cri teria. . . . . . . . . . . . . . . . .
2
6
6
6
6
7
12
15
17
17
18
18
19
26
29
32
32
33
33
34
37
37
37

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2.9
2.10
2.11
CONTENTS
Selected Remedy...... . . . . . . . . . . . . . . . . . . . . .
2.10.1
Statutory Determinations..................
2.10.2
2.10.3
2.10.4
Protection of Human Health and

Environment. . . . . . . . . . . . . . . . . . . . . . .
Compliance With ARARs.............
Cost Effectiveness................
Utilization of Permanent Solutions
and Alternative Treatment
Technologies to the Maximum Extent

Practicable. . . . . . . . . . . . . . . . . . . . . . .
Documentation of Significant Changes.......
RESPONSIVENESS SUMMARY.~..........................
3.0
ATTACHMENT A
ADMINISTRATIVE RECORD INDEX
3
PAGE
39
39
40
40
41
41
42

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FIGURES
1
PAGE
Facility Location Map... .... . ......... . .. .. ... 13
2
Location of Operable Unit 1................... 14
3
Manganese Concentrations (Fall 1991) .......... 23
4
Manganese Concentrations (Spring 1992) ........24
S
Manganese Concentrations (Fall 1992) .......... 2S
6
Manganese Concentrations (Fall 1992)
Cross Section A-A'........................ 27
7
Manganese Concentrations (Fall 1992)
Cross Section B - B' . . . . . . . . . . . . . . . . . . . . . . .. 28
8
Contaminants Exceeding Remedial Action Goals.. 3S
TABLES
1
Potential Contaminants of Concern.............20-21
~
Human Health Risks Greater than 1E-04......... 30

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ADEC
AFB
ARARs
BEEP
CERCLA
COC
EDB
EPA
HI
IRP
MCL
NCP
NPL
PA/SI
PCA
PCB
PPM
OU
RI
ROD
SARA
TPH
TRC
UCL
ACRONYMS AND ABBREVIATIONS
Alaska Department of Environmental Conservation
Air Force Base
Applicable Relevant and Appropriate Requirements
Bis (2-ethylhexyl) phthalate
Comprehensive Environmental Response Compensation and
Liability Act
Contaminant of Concern
l,2-Dibromoethane
Environmental Protection Agency
Hazard Index
Installation Restoration Program
Maximum Contaminant Level
National Contingency Plan
National priorities List
Preliminary Assessment/Site Investigation
l,l,2,2-tetrachloroethane
Polychlorinated Biphenyl
Part Per Million
Operable Unit
Remedial Investigation
Record of Decision
Superfund Amendments and Reauthorization Act
Total Petroleum Hydrocarbons
Technical Review Committee
Upper Conficence Limit

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SECTION 1
DECLARATION OF THE RECORD OF DECISION
1.1
SITE NAME AND LOCATION
Elmendorf Air Force Base (AFB)
Operable Unit (OU) 1
Anchorage, Alaska 99506
1.2
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected final remedial
action for OU1 at Elmendorf AFB, Alaska~ which was chosen in
accordance with the Comprehensive Environmental Response,
Compensation, and Liability Act of 1980 (CERCLA), as amended by
the Superfund Amendments and Reauthorization Act of 1986 (SARA),
and, to the extent practicable, the National Oil and Hazardous
Substance Pollution Contingency Plan (NCP). The decision is
based on the administrative record for this site. The
Adrninistrative Record Index is at Attachment A. The remedy was
selected by the U.S. Air Force and the U.S. Environmental
Protection Agency (EPA). The State of Alaska Department of
Environmental Conservation (ADEC) concurs with the selected
remedy.
1.3
ASSESSMENT OF THE SITE
Elevated levels of manganese occurring in the shallow groundwater
beneath this site, if not addressed by implementing the response
action selected in this Record of Decision (ROD), may present an
imminent and substantial endangerment to public health, welfare,
or the environment.
1.4
DESCRIPTION OF THE SELECTED REMEDY
The selected remedy addresses groundwater at OU1, one of seven
OUs identified at Elmendorf AFE. The purpose is to reduce the
risks associated with exposure to shallow groundwater and thus
address the main threat at the site. To accomplish this goal
the selected remedy includes institutional controls specifically
aimed at restricting use of the shallow aquifer as well as
groundwater monitoring to ensure protection of human health and
the environment.

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The maJor components of the selected remedy are:
.
monitoring groundwater for five years, or until the
groundwater no longer poses an unacceptable health
risk;
.
five-year review to assess the protectiveness of the
remedial action;
.
periodic evaluation of monitoring results to determine
if there is need for further remedial action; and
.
maintaining institutional controls restricting access
to shallow groundwater.
SPECIFIC INSTITUTIONAL CONTROLS
These controls will remain in effect as long as the Air Force
maintains active control of the area or until the groundwater
contamination dissipates to such levels that will no longer pose
any unacceptable human health or environmental risks. The
specific institutional controls to be implemented and/or
maintained at OUl are as follows:
.
.
.
~.s
.
Development of a site map showing the areas currently
and potentially impacted by groundwater contaminants;

Zoning the affected area for undeveloped
outdoor/recreational use only;
Continued enforcement of base policy prohibiting
installation of groundwater wells (other than for
monitoring purposes) into the shallow aquifer
underlying OUl at Elmendorf AFB; and
Securing of existing water supply and groundwater
monitoring wells.
STATDTORY DETERMINATIONS
The selected remedy is protective of human health and the
environment, complies with Federal and State requirements that
are legally applicable or relevant and appropriate to the
remedial action, and is cost-effective. This remedy utilizes
permanent solutions and alternative treatment to the maximum
extent practicable. However, treatment of the groundwater was
found to be impractical because of the potential to release other
harmful constituents in the process; therefore, the remedy does
not satisfy the statutory preference for treatment as a principal
element.

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Because the remedy will result in the continued presence of
hazardous substances on the site above health-based levels, a
review will be conducted within five years of commencement of the
remedial action, to ensure that the remedy continues to provide
adequate protection of human health and the environment.
. .

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LEAD AND SUPPORT AGENCY ACCEPTANCE
OF THE RECORD OF DBCXSION,
ELMENDORF AIR FOR.CE BASE, ALASltA
OPERABLE UNIT 1 .
Signature sheet for the foregoing Record of Decision for the
Operable Unit 1 final action at Elmenqorf Air Force Base, Alas~a
between the United States Air Force and the United States
Environmental P~otection Agency, with concurrence by the State of
Alaska Department of Environmental Conservation.
~ tlv&w-

THOMAS W. L. McCALL, Jr.
Deputy Assistant Secretary of the Air Force.
(Environment, Safety, and Occupational Health)
-3,;L~ ~1
Date

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LEAD AND SUPPORT AGENCY ACCEPTANCE
OF THE RECORD OF DECISION.
E~ORF AIR FORCE BASE. ALASKA
OPERABLE UNIT 1
Signature sheet for the foregoing Record of Decision for the
Operable Unit 1 final action at Elmendorf Air Force Base. Alaska
between the united States Air Force and the united States .
Environmental Protection Agency, with concurrence by the State of
Alaska Department of Environmental conservation.
~ CfJJL

CHUCK CLARKE
Regional Administrator
Region X
U.S. Environmental protection
~ 1z..9/e;4-
Date
Agency

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LEAD AND SUPPORT AGENCY ACCEPTANCE
OF THE RECORD OF DECISION. .
ELMENDORF AIR FORCE BASE. ALASKA
OPERABLE UNIT 1
Signature sheet for the foregoing Record of Decision for the
Operable Unit 1 final action at Elmendorf Air Force Base, Alaska
between the United States Air Force and the United States
Environmental Protection Agency, with concurrence by the State of
Alaska Department of Environmental Conservation.
~\\.~c('
JANICE ADAIR
Regional Administrator
Southcentral Regional Office
Alaska Department of Environmental
~(:CC"-.L~
Ci (jCt I CjL{
Date
con~ervation

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SECTION 2
DECISION SUMMARY
This Decision Summary provides an overview of the problems posed
by the conditions at aUl, the remedial alternatives, and the
analysis of those options. Following that, it explains the
rationale for the remedy selection and describes how the selected
remedy satisfies statutory requirements.
2.1
SITE NAME, LOCATION, AND DESCRIPTION
Elmendorf AFB is located on 13,035 acres bordered on the south by
the city of Anchorage, on the east by the u.s. Army's .Fort
Richardson, and on the north and west by the Knik Arm of Cook
Inlet (Figure 1). Base operations since the mid-1940s have
generated varying quantities of hazardous and non-hazardous
wastes. The major sources of hazardous wastes include industrial
operations (shops), fire training and fuels management.
There are 29 source areas being addressed under CERCLA at
Elmendorf AFB. These were divided into 7 operable units for
investigation. The ROD for OUI is the first of six planned for
documenting final action.
OUI consists of five general waste disposal areas (LF05, LF07,
LF13, LF59, and OT56) located next to the Davis Highway (Figure
2). Each of these source areas is described below. The area is
zoned undeveloped outdoor recreational use and consists of grassy
fields, gravel pits and wooded areas adjacent to Ship Creek.
LF05 - This 17-acre landfill was operated from 1951 to 1973.
General refuse, scrap metal, used chemicals and other scrap
materials were disposed in this landfill.

LF07 - This 35-acre landfill was operated from 1965 to 1982 for
the disposal of base-generated refuse, scrap metal, construction
rubble, drums of asphalt, empty pesticide containers and small
amounts of shop wastes. A portion of the landfill also received
wastes containing asbestos until 1992.
LF13 - This 2-acre, former gravel pit was used as a disposal area
for empty drums, metal piping, drums of asphalt and small
quantities of quicklime from 1967 to 1971.

LF59 - This area consists of two one-half acre landfills and a
tar seep in the southwestern portion of OUI. The landfills
received general refuse and construction debris from 1965 until
1983. The tar seep is located in a wooded area next to the base
jogging trail and is a remnant of a former asphalt .
batch plant located near Second Avenue and Davis Highway.

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OT56 - This Defense Reut~lization and Marketing Office area
occupies approximately 2.5 acres. Various materials, such as
scrap metal and drums, were stored in the area for an unknown
period of time. OT56 is no longer in use.
Ship Creek, located directly south of OU1, forms the major
topographic feature at the site. OU1 is part of the lower Ship
Creek drainage area. The stream valley of Ship Creek crosses
through the Elmendorf property for 4.2 miles between Fort
Richardson and Post Road. Ship Creek has the only lOO-year
floodplain designated on the installation..Wetlands occupy a
portion of the Ship Creek valley, occupying abandoned stream
channels and oxbows. Most are only seasonally flooded during
high flow periods, and are not considered to be prime wildlife
habitat. The most commonly seen species observed in these areas
is the wood frog. Surface-water from Ship Creek has been used
extensively at Elmendorf APB for a number of years. Much of the
surface water collected is used for indus~rial, fire fighting,
hospital, and domestic utility uses.
Elevations across OUl range from a high point of approximately
215 feet above mean sea level in the northeast to a low point of
approximately 175 feet above mean sea level in the southwest.
The surface is underlain by unconsolidated, permeable sands and
gravel of the glacial outwash plain. The sediments are flat
lying to gently sloping in a southern to southwestern direction
toward Ship Creek. The horizontal gradient is approximately 110
feet per vertical mile.
Two major sources of groundwater have been identified in the
Anchorage area: a shallow, unconfined aquifer system, and a
deeper, confined (artesian) aquifer. The Bootlegger Cove
formation forms the lower limit of the shallow aquifer and is the
confining layer of the deepe~ artesian aquifer.

OU1 is located approximately three-quarters of a mile northeast
of the nearest populated subdivision of the City of Anchorage and
is separated from the populated area by Ship Creek. .
2.2
SITE HISTORY AND ENFORCEMENT ACTIVITIES
Contaminant source areas LF05, 'LF07, and LF13 were first
investigated through a records search as part of the 'Preliminary
Assessment/Site Investigation (PA/SI) conducted by the Air Force
in 1983. Characterization of contaminant distribution within the
landfill area was initially investigated in 1986 during the SI
studies. As part of the site investigation, four groundwater
monitoring wells were installed and sampled. During construction
of the monitoring wells, four subsurface soil samples were
collected. During 1988, additional field investigations were
conducted at LF05 and LF07, including completing a geophysical
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survey, installing six additional monitoring w211s, sampling Ship
Creek near GUl, and sampling groundwater from all existing
groundwater monitoring wells, including Base WeIll. Base WeIll
is a shallow well located in the Ship Creek alluvium near the
southwestern corner of QUI and formerly served as a potable water
supply for the base. Contamination was detected in groundwater
samples collected in 1988. The geophysical survey indicated that
buried wastes were present in both areas. Findings and
conclusions of the individual investigations are available in the
final reports for each. These reports and other pertinent
documents are part of the administrative record for the site.
In 1990, the State of Alaska, Department of Transportation and
Public Facilities determined the presence of volatile organic
contamination in a gravel stockpile located within source area
LF07. Gravel from this stockpile was used as road base in the
construction of a portion of Boniface Parkway. Because
contaminants were known to exist in groundwater at QU1, the
gravel was also sampled. Ten soil samples collected from the
'stockpile revealed volatile organic contamination.

Source areas LFOS and LF07 were investigated again in 1990 using
gamma logging of boreholes, subsurface soil sampling of
boreholes, reviewing aerial photographs, performing terrain
conductivity and ground-penetrating radar surveys, and installing
six additional monitoring wells. Water-level measurements were
made at 13 wells within QUI to assess the local groundwater flow
directions. Groundwater samples were also collected from all
groundwater monitoring wells at QU1. Base WeIll was sampled for
comprehensive chemical analyses. In addition, slug tests were
conducted in seven wells within QUl.
Elmendorf AFB was proposed for the National priorities Lis.t (NPL)
in 1989 and placed on the NPL in August of 1990. In November
1991, a Federal Facilities~Agreement negotiated between the
Agencies established a cleanup schedule for the base.
In accordance with the new cleanup schedule, additional field
investigations were performed at QUI in 1992 to supplement
earlier studies and to provide additional subsurface soil,
surface soil, sediment, surface water, and groundwater data.
These data were needed to complete a RI, baseline risk .
assessment, and feasibility study. At the conclusion of this RI
a total of 32 groundwater monitoring wells, 20 methane monitoring
.wells, and 27 soil borings had been installed.
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2.3
HIGHLIGHTS OF COMMUNITY PARTICIPATION
In 1992, Elmendorf AFB assembled a Technical Review Committee
(TRC) composed of representatives from local community councils,
federal and state regul~tory age~cies, and a community at large
member. Quarterly meet~ngs prov~de Elmendorf AFB an opportunity
to brief the TRC on installation environmental restoration
projects and to solicit input from the TRC. Three TRC meetings
were held during preparation of the investigation and feasibility
study reports for OU1. In those meetings, the TRC was informed
as to the scope and methodology of the OU1 investigation and
proposed plans for remediation. .
The Proposed Plan for OU1 was released to the public on April 4,
1994. This began a 30 day public comment period which ended on
May 3, 1994. Documents detailing the findings of the
investigation and evaluation of alternatives were.made available
to the public at information repositories. located at the
following locations: Consortium Library, University of Alaska,
Anchorage, Alaska; and Alaska Resources Library, Bureau of Land
Management, Federal Building; Anchorage, Alaska. Notice of the
availability of the proposed plan and of an upcoming public
meeting were published in the Sourdough Sentinel on April 1, 1994
and in the Anchorage Daily News on April 3, 1994. The public
meeting was held April 21, 1994 at the Federal Building,
Anchorage, Alaska. The purpose of the meeting was to inform the
public of the preferred alternative, the alternatives evaluated,
answer questions and seek public comment. Representatives from
Elmendorf APB, EPA, and ADEC were present at the meeting to
answer questions about OU1 and the alternatives considered.
Transcripts of the meeting and written comments received during
the comment period are included in the Administrative Record file
for the site. A responsiveness summary can be found at Section 3
of this ROD. ~
2.4
SCOPE AND ROLE OP OPERABLE UNIT
The Federal Facility Agreement organized the CERCLA study sites
at Elmendorf AFB into seven OUs, on the basis of geographic
proximity and similar source characteristics or contaminants.
OU1, the subject of this ROD, .addresses problems resulting from
the release of hazardous substances from five waste disposal
areas described in Section 2.1; however, potential environmental
concerns outside of CERCLA are being addressed under separate
base cleanup programs as discussed below.

The OU1 investigation determined that the solid wastes do not
warrant further action pursuant to CERCLA. Certain solid wastes,
including the tar seep at LF59 and scrap metal that is scattered
throughout the area, are being investigated under separate base
cleanup programs under jurisdiction of Alaska's solid waste.
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regulations. In addition, a permitted sanitary landfill formerly
operated upgradient of the OUl landfills is being closed pursuant
to the States' solid waste program.
Furthermore, OU6 will investigate environmen~al risks to Ship
Creek (within the boundaries of Elmendorf AFB) to determine the
full environmental impact from all nearby operable units,
including OUl. The ROD for OU6, due in August 1996, will
finalize CERCLA activities at Elmendorf AFB.
2.5
SITE CHARACTERISTICS
OU1 has been the subject of several investigations conducted
between 1981 and 1993. The data from studies prior to 1991 were
not validated, so those data were reviewed and analyzed and used
to select locations for the subsequent field work, the analytical
results of which are compiled in the RIfFS for QU1. The RI
leading to this ROD was conducted in three phases during fall
1991, spring 1992, and fall 1992. Soil borings drilled in and
around OU1 have been used to determine the presence and extent of
soil contamination and to investigate the geology of the site. A
network of 32 groundwater monitoring wells was used to identify
and map groundwater contamination and to determine aquifer
characteristics.
2.5.1
Geoloav and Hvdroqeoloqy
Th~geology of QU1 was investigated by logging borings drilled in
soil, by surface geology investigations, and by interpretation of .
geophysical survey results.

Two major sources of groundwater have been identified in the
Anchorage area: a shallow, ~nconfined aquifer system and a
deeper, confined (artesian) aquifer. The Bootlegger Cove
formation forms the lower limit of the shallow aquifer and is the
confining layer of the deeper artesian aquifer.
The shallow aquifer consists of alluvial deposits from Ship
and glaciofluvial gravel deposits which are typical in the
outwash plain south. of the Elmendorf moraine, the dominant
topographic feature on Elmendorf AFB.

Surficial alluvial deposits at OU1 are comprised of channel
gravels and sands deposited in and on either side of Ship Creek.
These deposits are approximately one-third of a mile wide where
Ship Creek transects QU1. These deposits are generally well
bedded and well sorted. .
Creek
Outwash plain gravels were deposited from braided glacial
meltwater streams issuing from the ice margin. Outwash plain
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deposits at OU1 consist of a relatively homogeneous seqJe~ce 0:
massive to crudely bedded, poorly sorted sandy gravels and
include relatively thin lenses of sand. Thick sections of these
deposits can be seen in the walls of the landfills at OU1.
Channeling is common, and the gravel forms pods, lenticular
bodies, and channel fills. Fluvial features such as point bar
sands and channel lag gravels can also be observed. These
deposits directly overlie the Bootlegger Cove formation and,
based on drillhole intercepts, average 108 feet thick in the
central landfill area and 75 feet thick in the vicinity of LF59.

The Bootlegger Cove formation is a fine-grained glacioestuarine
deposit composed of silt, clay and sand with fines. The surface
topography of the formation is hummocky with incised channels,
fODmed from glacial outwash streams. The thickness of the
formation is not well defined due to its variability and
gradational contacts. Gradational zones above and below the
Bootlegger Cove, approximately 20 to 25 feet thick, are
characterized by interfingered clays, silty sand, and gravel.
Underlying the Bootlegger Cove are older glacial deposits. These
deposits compose the principal aquifer underlying Anchorage.
Because of both topographic and lithologic variability, the depth
to saturation within the individual shallow aquifer units varies
from ground surface to more than 50 feet. Water-level depths in
wells at OU1 range from 5.38 feet below ground surface near Ship
Creek to 40.57 feet below ground surface near the southeast
corner of OU1.
A review of historical water levels and water levels collected
during the RI field work shows shallow aquifer groundwater flow
direction. Along the eastern boundary of OU1, flow is toward the
west-northwest; near the western extent of OU1, it has a west-
southwest component. The average hydraulic gradient within the
unconfined aquifer ranges between 0.004-0.007 ft/ft.
2.5.2
Nature and Extent of Contamination
The environmental media sampled during the 1991-1992 RI were
soil, sediment, surface water, and groundwater. The results of
the investigation are summarized below. Discussion has been
limited to contaminants that were determined to be of concern as
described in the summary of site risk, Section 2.6.
The extent of contamination in surface and subsurface soils was
assessed by collecting soil samples for chemical analyses. The
sampling is discussed in detail in the RI/FS Report. Table 1
presents information on the frequency of detections and
concentrations of compounds found in the soil and other media at
OU1.
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TABLE 1
POTENTIAL CONTMllNANTS OF CONCERJ.'l
CONTAMINANT MAXIMUM DETECTION F~QUENCY MAXIMUM 
     RISK/HIt 
 CONC    
GROUNDWATER lli9.L!l Well/Date   
Benzene 2.5 LF05-MW07/F92 5/54 2.5E-06 
BEHP' 68.0 LF05-MW13/F92 12/52 1.0E-05 
1.2-DibromoethaneJ 0.38 LF05-W5/F92 7/43 3.8E-04 
Cis 1.2-Dichloroethene 6.7  LF05-2C/F92 8/53 < 1.0E-06 
Methylethylketone 290.0 LF05-MWll/F92 3/52 < 1 .OE-06 
Polychlorinated Biphenyl~ 14.0 LF05D1302/F91 1138 3 .4E-03 
1.1.2.2-PCA6 11.0 LF59-MW02/F92 3/51 6.8E-05 
Tetrachloroethylene 3.7  LF05GW28/S92 4/53 1.6E-06 
Toluene 110.0 LF05-MWll/F92 6/52 < 1.0E-06 
Trichloroethylene 8.2  LF05GW2B/F91 7/53 2.1 E-06 
Vinyl Chloride 3.3  LF05-MWl 0/F92 1/52 8.4E-05 
Arsenics 140.0 LF05-W6/F92 33/47 2.9E-03 
Barium 610.0 LF05-MW10/F92 32/53 < 1 .OE-06 
Beryllium 7 3.0  LF05GW2B/F91 1/53 1.6E-04 
Fluorides 5200.0 LF05GW2B/F91 5/53 2.4 HI 
Lead' 130.0 LF05-W5/F91 35/53 63% 
Manganese 33300.0 LF05-MW04/F92 52/53 198.0 HI 
Nickel 310.0 LF05-MWl 0/F92 23/53 < 1.0 HI 
I SURFACE WATER l i~"tJ.o I 11~ INA I
TPH'O
SEDIMENT (marka} ~   
TPH'O 120.0  4/4 NA 
LEAD'1 21.7  4/4 NA 
SURFACE SOIL (maiko)    
Benzo lal anthacene   0.58  1115 3.8E-06 
Senzo (kl fluoranthene   0.43  1/15 2.9E-06 
BEHP 13.0  1/15 < 1 .OE-04 
2 -Methynaphthalene 12   1.2  4/15 NA 
Antimony 14.6  1/15 <1.0 HI
. Arsenic   8.0  11/15 < 1 .OE-04 
Barium 2110.0  5/15 < 1.0 HI 
Cadmium 20.6  2/15 < 1.0 HI 
Copper 135.0  15/15 < 1.0 HI 
Lead13 346.0  1 5/1 5 NA 
Mercury 1~   0.3  5/15 NA 
-------
TABLE 1 (Continued)
POTENTIAL CONTAMINANTS OF CONCERN
I CONTAMINANT I MAXIMUM DETECTION I FREQUENCY I ~~ I
  CONC   
SUBSURFACE SOIL (maiko)   
Benzo (b) fluoranthene 0.25 1/197 N/A 
Chrysene  0.5 ., /1 07 N/A 
PCB (Aroclor 1260) 0.42 1/90 N/A 
TPH'6  35000.0 86/92 N/A 
Arsenic,a  30.9 84/1 02 N/A 
 N/A 
Beryllium  0.7 2/102 N/A 
Sodium " 1 180.0 100/102  
1 Risk from drinking groundwater from an unfiltered shallow well in the immediate vicinity of the highest concentration of
cae over a time of 30 years.
2 BEHP = Bis.(2-ethylhexytl phthalate
3 1,2-Dibromoethane (EDSI was only detected once with a concentration above EPA acceptable risk ranges.
4 Polychlorinated Biphenyl (PCBI was only detected once in one well, subsequent sampling events failed to confirm it's
presence. Data is of questionable validity.
5 1,1.2.2.PCA = 1.1,2,2.tetrachloroethane.
6 Only four samplas detected slightly above background risk. Risk does not appear to be site related.
7 Only detected once and risk did not exceed the sample quantification limit risk.
8 Only one detection above the HI of 1.0
~
9 When gre8ter than 5% of potentially exposed children are estimated to have blood levels exceeding 10 ug/l, a hazard due
to lead is deemed to exist. Only one well location is associated with total lead concentrations across all three rounds of
sampling greater than 5%.
10 TPH = total petroleum hydrocarbons. Data is not usable for risk assessment.
11 Not significantly different than background and exposure very highly unlikely.
12 No toxicity established and not a suspected carcinogen.
13 All were within background range except for only one ~ample.
14 Toxicity values not available. Three samples close to background range with others under.
15 All detects are TPH. Only seven samples were above state cleen-up levels for non-UST contaminated soil.
-------
The presence of contamination in surface water was assessed by
compiling and reviewing data collected by the Elmendorf AFB
Bioenvironmental Services. In addition, surface water samples
were collected and analyzed from seeps and surface water bodies
at LF59. The procedures used and results of surface water
sampling are discussed in the RI/FS Report for OUI.
The extent of contamination in groundwater was assessed by
collecting samples for chemical analyses from 31 new and existing
.wells. Water samples were collected in fall 1991, spring 1992,
and fall 1992. The majority of the monitoring wells are screened
in the shallow, unconfined aquifer, with the exception of 2 deep
wells installed to monitor the confined aquifer underneath the
Bootlegger Cove formation. Well construction and groundwater
sampling are discussed in detail in the RI/FS Report.
Five compounds were detected in groundwater at concentrations
that were later determined to be a poten~ial risk as described in
Section 2.6: arsenic, 1,2-dibromoethane (EDB), polychlorinated
biphenyl (PCB), lead, and manganese. .
Arsenic was detected in four monitoring wells at levels only
slightly above background conditions. The maximum concentration
of arsenic detected was 140.0 ugfl in well LFOS-W6. The high
natural background concentration for arsenic is 76.0 ugfl (USGS).
.The maximum contaminant level (MCL) for arsenic is 50.0 ug/1.
The maximum concentration detected of 1,2-dibromoethane CEDB) was
0.38 ugfl in well LFOS-W5. Although EDB was detected several
times in the fall 1992 sampling event, only once was it detected
above the MCL of 0.05 ugfl.
PCB (Aroclor 1260) was detected at a concentration of 14.0 ugfl
only once, in well LFOS-D13t02; 2 subsequent sampling events in
the same well failed to confirm the presence of PCB. It is
highly unlikely that this level of PCB could drop to undetectable
levels, and the validity of the previous data is in question.
Lead exceeded the EPAs drinking water benchmark level of 15 ugfl
when a concentration of ljQ ugfl was detected in fall 1991 in well
LFOS-WS. Only two other wells, excluding upgradient wells, had
concentrations which exceeded "this benchmmark level.
Of the five, only the manganese was observed consistently and
widespread throughout groundwater at the site. Figures 3, 4, and
5 depict manganese concentrations detected over the three rounds
of sampling. Data obtained were compared with background
conditions which were determined as follows: Groundwater samples
were collected from upgradient wells GW-~ and GW-2A on four
occasions and analyzed for total manganese: summer 1988, fall
-------
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-------
199: SDr~TIg 1992, and fall 1992. Sta~istical tec~niGJes we~e
used t~ define an appropriate "background" total man~anese level
using these eight values. Specifically, the "background" total
manganese level was chosen to be the 5 percent upper confidence
limit (UCL) on the mean of the log transformed groundwater data
from the upgradient wells. Any value greater than the 95 percent
DCL is significantly greater than the mean of the upgradient
data. The eight upgradient total manganese values ranged from
500 to 26,000 uga. The highest values, 13,000 uga (GW-IA) and
26,000 uga (GW-2A) were reported from samples..collected in August
988. The 5 percent UCL was calculated to be 9,100 uga.
Manganese concentrations detected during the first two rounds of
sampling were consistent with background conditions. Prior to
the fall 1992 sampling event an additional seventeen monitoring
wells were installed. The maximum concentration of manganese
detected, 33,300.0 uga in well LF05-MW04,.was not observed until
the final round of monitoring during autumn 1992. Data obtained
then indicated elevated levels of manganese coincidental with
waste disposal cells within the landfill and the gas station area
at OUI (see figure 5). Manganese concentrations at downgradient
locations were below statistically derived background conditions,
as is evident in groundwater samples collected from the LF59
source area and from monitoring wells west of the L05/0T56 source
areas. It appears that no groundwater contaminant plumes exist
over time and that the manganese concentrations are not
migrating. Figure 5 also shows the location of 2 cross
sections. These cross sections, Figures 6 & 7, illustrate the
depth at which manganese concentrations were detected, and
conceptualize ideas regarding the cause of the manganese
concentrations.
Soil concentrations of manganese are naturally high in the area
as is common with glacial deposits. Data obtained from soil
borings in the vicinity of the landfill cells did not indicate an
unnatural source of manganese contamination. The reduction of
solid manganese oxides to the soluble manganese species could be
caused by bacterial decomposition of organic matter in the
subsurface. As microorganisms degrade organic compounds in the
subsurface, oxygen is consumed and aquifer conditions become
reducing. These reducing conditions may cause the spontaneous
dissolution of manganese or contribute to bacterially-mediated
manganese liberation.
2.6
SUMMARY OF S~TE RISKS
This section summarizes the human health risks and environmental
impacts associated with exposure to site contaminants and
provides potential remedial action criteria.
-------
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-------
2.6.1
Human Health Risks
A baseline risk assessment was conducted to estimate the risk
posed to human health by OUI. The risk assessment consisted of
an exposure assessment, toxicity assessment, and human health
risk characterization. Chronic exposures to contaminated media
are not currently occurring at OU1. The human health risk
assessment therefore is based on two hypothetical exposure
scenarios: a future residential land use scenario and a future
commercial/industrial land use scenario.
The health risk evaluation used both the exposure concentrations
and the toxicity data to determine a Hazard Index (HI) for
potential noncarcinogenic effects and a cancer risk probability
for potential carcinogenic contaminants. . In general, an HI of
less than or equal to 1 indicates that even the most sensitive
individual is not likely to experience adverse health effects.
The degree of concern typically correlates with the magnitude of
the index if it is above 1. The cancer risk level is the
additional chance that an exposed individual will develop cancer
over the course of a lifetime. It is expressed as a probability
such as 1E-06 (one in one million) .
Contaminants of concern (COCs) were identified using the
screening method suggested in the supplemental guidance for
Superfund Risk Assessments in EPA Region X (EPA 1991). This
method, called the "ri.sk-based screening approach", compares the
highest concentration of each chemical detected at a site to a
risk-based screening concentration. According to the National
Contingency Plan a risk range of 1E-04 to 1E-06 is acceptable.
At 'OU1 the COCs detected did not occur at concentrations above
EPA acceptable risk ranges in soil nor in surface waters. The
only COCs identified were in the shallow groundwater at OU1.
COCs detected were arsenic, BDB, PCB, lead, and manganese.
Risks were calculated using exposure point concentrations equal
to the highest concentrations detected (see Table 1). Exposure
assumptions include potential future receptors drinking and
showe~ing from an unfiltered shallow well in the immediate
vicinity of the highest concentration of COCs over a time of 30
years. Sources of toxicity data used in the risk assessment were
(in order of preference): Integrated Risk Information System
(IRIS), Health Effects Assessment Summary Tabs (HEAST), and the
USEPA Superfund Technical Support Center. Risks associated with
the five COC are presented in Table 2.
A comparison of site-related risk and risk associated with
background conditions indicates that risks associated with
arsenic are not site related. Risk for arsenic was calculated
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TABLE 2
HU"'l\IAN HEALTH RISKS GREATER TH.A1~ lE-04
I CONTAMINANT  I SITE RELATED - I BACKGROUND I
   RISK/HI I ' CONC (ug/l)  RISK/HI2 CONC (ug/l) 
Arsenic  2.9E-04 140.0  1. 8E- 04 76.0 
l,2-Dibromoethane 3.8E-04 0.38 NA  
Manganese  198.0 HI 33,300.0  36.3 HI 9,100.0 
PCB (Aroclor 1260) 3.4E-03 14.0  NA  
Lead   63%3  130.0  6%4 45.0 
1 Risk associated with from drinking groundwater from an
unfiltered shallow well in the immediate vicinity of the highest
concentration of COC over a time of 30 years.
2 Risk associated with drinking groundwater with background
concentration of COC over a time of 30 years.
3 Percentage of children ages 0 to 7 who would have a blood-lead
level of greater than 10 ug/dl after ingesting water containing
130 ugn of lead. Calculated using the EPAs Biokinetic Uptake
Model.
4 Percentage calculated the same as for note 3,
is based on a lead concentration of 45 ugfl that
an upgradient monitoring well, LF05-GW-2A.
~
above. The value
was detected in
-------
using a maximum concentration of 140.0 ug~, detected in well
LFOS-W6. Background risk for arsenic was calculated using the
high natural background concentration of 76.0 ug~ (USGS).
The risks calculated for EDB were based on a maximum
concentration of 0.38 ugfl detected in well LF05-W5. This
only detection of EDB above the MCL of 0.05 ug~ and above
acceptable risk range of .00075 ug~ to .075 ug~.
was the
the EPA
For PCB (Aroclor 1260) risk was determined using the only
concentration detected of 14.0 ugfl, in well'LF05-D13-02. As
discussed in Section 2.5 this data is of questionable validity.
Risks were calculated for lead using EPAs Biokinetic Uptake
Model. The model was developed to estimate the level of lead in
blood, since this is the most sensitive indicator of lead
exposure. EPA-has determined that a blooe-Iead range of 10 ug to
15 ug/dl (micro-grams of lead per deci-liter of blood) represents
a level of concern. It is generally accepted that if no more
than 5 percent of exposed children are estimated to have blood
lead levels of 10 ug/dl, a significant health hazard due to lead
is not deemed to exist. The model incorporates media-specific
uptake factors for exposure to lead, concentrations of lead, and
exposure factors. Site-specific information on lead levels found
at OU1 were entered into the model and the resulting values were
compared with EPA's level of concern of 10 ug/& using probability
density functions. The percentage of children estimated to have
blood lead levels above 10 ug/dl of blood was greater than 5
percent at only four out of thirty-one locations monitored within
OU1: LF05-W-5 with 63% based on a maximum concentration of 130
ugfli LF05-W-6 with 6% based on a concentration of 46 ug~; LF05-
NS2-01 with 8% based on a coqcentration of 49 ugfl; and LF05-GW-2A
with 6% based on a concentration of 45 ugH. Furthermore, LF-OS-
GW2A is an upgradient of monitoring locations. The sporadic
detections of lead at OU1 do not appear to pose any threat under
the current land use scenario.
Of the contaminants detected above acceptable risk ranges, only
manganese was observed consistently and widespread throughout
shallow groundwater at OU1. ~~sk associated with manganese were
calculated using a concentration of 33,300.0 ug/l, detected in
well LF05-MW04. Background risks for manganese were calculated
using a background level for manganese of 9,100 ug/l, based on a
range of background concentrations ranging from 500 to 26,000
ug/l. The background concentration was statistically derived as
described in Section 2.5.
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2.6.2
uncertainties Associated With the Risk Assessment
Risk assessments involve calculations based on a number of
factors, some of which are uncertain. The effects of the
assumptions and the uncertainty factors may not be known.
Usually, the effect is difficult to quantify numerically, so the
effect is discussed qualitatively. Some of the major assumptions
and uncertainty factors associated with the risk assessment are
the following: . .
2.6.3
.
The assessment used EPA Region 10 default exposure
parameters for most calculations~' Some of these
parameters are not realistic for a subarctic climate
(May overestimate risk) .
.
Existing concentrations are assumed to be the
concentrations or exposure source terms in the
No reduction through natural degradation and
attenuation over time is taken into account
(May overestimate risk) .
future.
.
No increase through additional contamination is assumed
(May underestimate risk).
.
Potential degradation products of existing organic
contaminants are not considered (May overestimate or
underestimate risk).
Environmental Evaluation
An ecological assessment was conducted at OU1 which determined
risks that exist for both the terrestrial ecosystem and the
aquatic ecosystem. The characterization of the aquatic risks,
specifically those at Ship Creek, was uncertain due to the
limited availability of data. Risk to the aquatic ecosystem are
being investigated further under OU6 studies ongo~ng at the base.
The terrestrial risk assessment identified a potential
environmental risk due to the presence of several heavy metals
within the soils of OU1. These metals include cadmium, mercury,
. lead, and barium. Cadmium was found at only one surface soil
sample location. Mercury was detected in concentrations up to
0.26 mg/kg at three surface soil sample locations east of the
Davis Highway and two locations west of the highway at OU1. Lead
was detected in concentrations exceeding 25 mg/kg at only two
locations east of the Davis Highway and none to the west.
Barium was found in concentrations exceeding 150 mg/kg at three
locations, one east of the Davis Highway and two to the west.
-------
These high levels are an indication of isolated "hot spots"
do not pose a significant risk and do not warrant remedial
action.
w:::.::~
Localized small mammal and passerine bird populations at OUl may
be at risk from ingestion of heavy metals. However, exposure to
heavy metals is expected to be limited due to the limited aerial
extent of contamination and the relatively large habitat. The
results of the ecological risk assessment indicate potential
theoretical risk to migratory peregrine falcons exposed to heavy
metals at OU1. However, there is no habitat 'at OU1 which would
attract peregrines to the area, making it extremely unlikely they
would come in contact with contaminants at the site. Also, there
have been no verified sightings of peregrines on Elmendorf APE in
the past seven years.
2.7
2.7.1
DESCRIPTION OF ALTERNATIVES
Remedial Action Ob1ectives
The Feasibility
remedial action
domestic use of
Risk Assessment
associated with
Study recommended that OU1 be considered for
because of the potential risk from unrestricted
groundwater containing manganese. The Baseline
concluded that the greatest risks at OUl are
manganese in the shallow groundwater.
Assumptions made during the RI/FS and decision making process
include:
.
The RI determined that concentrations of manganese
present in the site soils are commensurate with
background conditions and there is currently no
identifiable source of further groundwater.
contamination. Therefore, no remediation of the site
soils was deemed necessary, and no remedial action
objectives were developed for the site soils.
.
Data obtained during 1991 and 1992 indicate there are
no contaminant plumes in the groundwater at OU1 and
that the manganese is not migrating. This situation
makes most groundwater cleanup alternatives
ineffective, such as' pump and treat or containment of
the contaminated groundwater.

A reducing environment is thought to be responsible for
elevated manganese concentrations in groundwater.
Containment of the landfill by installing a cap would
locally reduce the infiltration of oxygen and
exacerbate the reducing environment, and is therefore
not considered effective.
.
-------
.
Existing land use controls prevent current expoSure to
shallow groundwater at the site and will be insured in
the future by Air Force policy and federal land
transfer regulations, in order to continue to prevent
exposure to manganese above health-based levels at the
site. -
The remedial action goal for the QUI source area is to prevent
ingestion/direct contact with groundwater containing contaminants
in concentrations in excess of background or MCLs, whichever is
greater.

The goal is to reach the concentrations described below:
Contaminant
Backqround (uffl)
MCL (ugfl)
l,2-Dibromoethane
0.05
Manganese
9,100.0
Trichloroethylene
5.0
Vinyl Chloride
2.0
Figure 8 shows contaminant concentrations detected during the
RI/FS that exceed these remedial action goals.
2.7.2
Remedial Alternatives
Three alternatives were developed and thoroughly analyzed in the
FS.
Alternative 1: No Action
~
Capital Cost: $0
Five-Year O&M Cost: $0
Evaluation of the No Action alternative is required under CERCLA,
serving as a common. reference point against which other
alternatives can be evaluated.
Under this alternative, no additional action would be taken to
mitigate or monitor the contaminants found at the site.
-------
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-------
Alternative 2: Limited Action with Long-Term Monitoring of
Groundwater
Capital Cost: $0
Five-Year Q&M Cost: $240,000
This alternative includes continued groundwater monitoring to
detect and evaluate any changes in contaminant concentrations and
maintaining institutional controls (including base directives and
restrictive covenants) to prevent the use of the contaminated
groundwater underlying QUI. .
Institutional controls would include:
.
Development of a site map showing the areas currently
and potentially impacted by groundwater contaminants;

zoning the affected area for undeveloped
outdoor/recreational use only;
.
.
Continued enforcement of base policy prohibiting
installation of groundwater wells (other than for
monitoring purposes) into the shallow aquifer
underlying Elmendorf AFB; and
.
Securing of existing water supply and groundwater
monitoring wells.
These controls will remain in effect as long as the Air Force
maintains active control of the area or until the groundwater
contamination dissipates to levels which are statistically
equivalent to background concentrations and that will no longer
pose any unacceptable human 1}ealth or environmental risks.
Wells will be monitored to evaluate the fate and transport of
contaminants at QUI and to verify assumptions made during the RI.
The details of monitoring and evaluation will be developed in the
QUI Long Term Monitoring Plan documents.
Alternative 3: In Situ Treatmen~ of Groundwater
Capital Cost: $201,000
Five-Year Q&M Cost: $495,000
Alternative 3 includes an in situ treatment process for
groundwater contaminated with elevated levels of manganese.
It is currently thought that low levels of organic compounds
released by the landfill interact with soil particles and allow
the manganese to be dissolved into solution in the groundwater.
-------
~his precess could be impeded by the injection of oxygen into t~e
shallow groundwater aquifer, causing the manganese to oxidize and
separate out. Once this occurs, the manganese would be adsorbed
onto soil particles in the aquifer, allowing the groundwater
manganese concentrations to return to backgrqund levels. This
process already appears to be occurring down gradient of the
elevated manganese concentrations.
The same groundwater monitoring program proposed under
alternative 2 would be used to monitor the effectiveness of this
treatment process. This alternative would need to be maintained
indefinitely, or until the chemical process releasing the
manganese ceased. Alternative 3 is an innovative technology,
which mayor may not achieve the desired objectives or could
induce other alterations in the groundwater which may mobilize
other soil constituents. This alternative is based on the
assumption that organics in LF07 are causing manganese levels in
groundwater to increase.
2.8
SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
This section summarizes the relative performance of each of the
three alternatives with respect to the nine CERCLA evaluation
criteria.
2.8.1
Threshold Criteria
Overall protection of human health and the environment.
Alternative I, No Action, provides no protecti~n for future users
of the site or for the environment. Alternatives 2 and 3,
Institutional Controls and In Situ Treatment, both provide
overall protection of, human~health in accordance with the NCP.

Achievement of Applicable Relevant and Appropriate Requirements
(ARARs). The Safe Drinking Water Act, Title 40 Code of Federal
Regulations, is relevant and appropriate. Under alternative 2,
groundwater will be monitored and institutional controls
maintained until sampling determines that the MCLs have been
reached and risks are acceptable.
2.8.2
Primary Balancinq Criteria
Long-ter.= effectiveness. The groundwater monitoring program
proposed under Alternative 2 would provide a long-term effective
measure by which human health and the environment would be
protected by alerting the Agencies if the manganese began to
increase or migrate. It is expected that long-term monitoring
will show that, over time, manganese concentrations will decrease
through natural processes.
-------
Alte~native 3 meets the remedial action objectives for
groundwater by reducing the elevated manganese to background
conditions and would be effective in removing/reducing existing
concentrations on a permanent basis. However, to be most
effective, Alternative 3 would need to operate until the landfill
cells no longer release organic compounds to the groundwater.

Reduction in toxicity, mobility, or volume of contaminants
through treatment. Alternative 2 does not actively reduce.
toxicity, mobility, or volume of the elevated concentrations of
manganese at OU'l. Alternative 3 would reduce..the toxicity,
mobility and volume of manganese in groundwater by actively
treating it. .
Short-ter.m effectiveness. None of the groundwater. remedial
alternatives would 1) cause any increased environmental impacts
or 2) pose additional short-term risks to workers or the
community. Under Alternatives 2 and 3 the effectiveness and need
for continuing the monitoring program would be re-evaluated by
the Agencies at the end of five years of monitoring.
Alternatives 3 would provide greater short-term effectiveness
because active groundwater treatment would decrease manganese
from. the start of remedial operations. Monitoring would help
ensure that the manganese does not impact any possible down-
gradient receptors. .
Implementability. Alternative 2 would be readily implementable
because of existing controls. Groundwater monitoring programs
and base institutional controls to restrict use of water in the
shallow aquifer are already in place. In addition, in the .event
of base closure, federal land transfer regulations would ensure
that these controls renained in place. Alternative 3 is not. as
readily implementable because the treatment technology has not
been applied and would requi;e a design and construction period.
Cost effectiveness. Long-term monitoring is the only cost
required for Alternative 2 and will cost $240,000 for five years.
Alternative 3 is estimated to cost $696,000 for initial
installation and five years of monitoring. There would be
additional costs for long-term monitoring, which were not
calculated in the feasibility study. Alternative 2 is considered
cost effective when compared with alternative 3.
2.8.3
MOdifvina Criteria
State acceptance. The State of Alaska concurs with the Air Force
and EPA in the selection of Alternative 2.
Public Acceptance. Based on the comments received from the public
and the support given by the TRC, the public supports the
selection of Alternative 2.
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2.9
SELECTED REMEDY
The selected remedy to manage risks posed by elevated manganese
concentrations in the shallow groundwater at QUI is Alternative
2: Limited Action with Long-Term Monitoring of Groundwater.
Alternative 2 is selected based on the following five site
specific considerations:
.
The groundwater monitoring program will provide early
warning of any increase in concentrations or movement
of manganese.
.
Existing land use controls will ensure no current
exposure to shallow groundwater. Institutional
controls and required property transfer provisions of
CERCLA will ensure that there will be no exposure to
shallow groundwater in the fut~re.
.
Elevated levels of manganese appear to be isolated
within a limited area and are not anticipated to
migrate.

The source of the mangane~e is uncertain.
.
.
There is no current human exposure to manganese in the
shallow groundwater.
The major components of the selected remedy include:
.
institutional controls;
.
monitoring groundwater for five years, or until the
groundwater poses an acceptable health risk;
I.
.
five-year review to assess the protectiveness of the
remedial action; and
.
periodic evaluation of monitoring results to determine
if there is need for further remedial action.
2 . ~O STATUTORY DETERMINATIONS
The selected remedy satisfies the requirements under Section 121
of CERCLA to: .
.
.
.
protect human health and the environment,
comply with the ARARs,
be cost-effective, and
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2.10.1
.
utilize permanent solutions and alternative treat~e~t
technologies to the maximum extent .practicable.
Protection of Human Health and the Environment
The selected remedy, Alternative 2, will reduce the risks posed
to future users of Operable Unit 1 by establishing institutional
controls that restrict use of the land and the shallow aquifer.
Current trends indicate reduction of contamination to background
levels occur naturally before groundwater migrates off-site. The
long-term monitoring will provide early warning of any increase
or movement of the manganese. Based on the above information,
the selected remedy is protective of human health and the
environment.
2.10.2
COmDliance with ARARs
The selected remedy calls for groundwater monitoring and
maintenance of institutional controls until sampling determines
that the remediation goals have been reached and risks are
acceptable. Therefore, the selected remedy complies with all
ARARs, listed below:
.
MCLs established under the Safe Drinking Water Act are
relevant and appropriate requirements for groundwater
that is a potential drinking water source:
Contaminant
1,2-Dibromoethane
Trichloroethylene
Vinyl Chloride
MCL (uga)
0.05
5.0
2.0
~
.
Alaska Oil Pollution Regulation (18 AAC 75). Under the
Alaska Oil Pollution Regulations, responsible parties
are required to cleanup Oil of Hazardous Substance
releases. Due to the sporadic, infrequent nature of
groundwater contaminant sample results and the lack of
source areas, it is the general opinion that the
groundwater contaminant trend is decreasing in
concentration through time. Under 18 AAC 75.327, the
ADEC has the authority to determine alternative cleanup
standards for groundwater. In accordance with this
requirement, the purpose of the monitoring is to verify
that groundwater contaminantion is decreasing and will
meet acceptable human health risk levels and Safe
Drinking Water standards within an acceptable time
limit, which is expected to be five years from
initiation of the monitoring program.
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2.l0.3
Cost-Effectiveness
The selected remedy is cost-effective because it has been
determined to provide overall effectiveness ~roportionate to its
costs and duration to achieve the remediation goals. Alternative
3 with a cost of $696 thousand plus additional costs for long
term monitoring that would be required by the State, is
significantly more costly than the selected remedy. Given the
uncertainty about the effectiveness of in-situ treatment,
introducing oxygen to the aquifer, the benefits of active
remediation do not justify the cost.
2.10.4
Utilization of Permanent Solutions and Alternative
Treatment Technoloqies to the Max~um Extent.
Practicable
The U.S. Air Force, the State of Alaska, and EPA have determined
that the selected remedy represents the maximum .extent to which
permanent solutions and treatment technologies can be used in
cost-effective manner at the QUl site. Of those alternatives
that are protective of human health and the environment and
comply with ARARs, the U.S. Air Force, the State of Alaska, and
EPA have determined that the selected remedy provides the best
balance of tradeoffs in terms of long-term effectiveness and.
permanence, reduction in toxicity, mobility, or volume achieved
through treatment, short-ter.m effectiveness, irnplernentability,
cost (as discussed in the preceding section), and the statutory
preference for treatment as a principal element and considering
State and community acceptance.

All alternatives would use readily available technologies and
would be feasible to construct. Alternatives 1 and 2 would be
readily implementable; they require no additional remedial
action. The technologies involved in Alternative 3 are
relatively limited in scope.
The most decisive factors in the selection decision were long-
term effectiveness and implementability. Alternatives 2 provides
the best option for cost-effective and practical remediation of
QUI, because it is expected manganese concentrations will return
to background conditions in time. Alternative 3 would in
principle reduce the concentrations of manganese in the aquifer
more quickly; however, given the fragile nature of the
geochemical environment, it presents considerable risk of
mobilizing additional contaminants that could prove more
hazardous than the existing conditions.
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2.11 DOCUMENTATION OF SIGNIFICANT CHANGES
The selected remedy was the preferred alternative presented in
the Proposed Plan. No changes have been made.
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SECTION 3
RESPONSIVENESS SUMMARY
The Proposed Plan for OU1 was issued to the public on 4 April
1994. This began a public comment period that ended on 3 May
1994. In order to encourage public comment, the USAF inserted
pre-addressed, written comment forms in distributed copies of the
Proposed Plan. In addition, comment forms were also distributed
at the 21 April 1994 public meeting held at the Federal Building
to receive comments on the Proposed Plan.
The public meeting was attended by 19 people, including 4
community members. Oral comments were received from 3 people:
one representative from Physicians for Social Responsibility, and
two citizens representing themselves.
Following the public meeting and prior to the conclusion of the
public comment period comments were submitted by three
individuals.
~l comments received are documented in the administrative record
file for the site. A transcript of the public meeting is
available for public review at the site information repositories.
The repositories are located at the Bureau of Land Management's
Alaska Resources Library and the University of Alaska at
Anchorage's Consortium Library.
Public comments, relevant to OU1 and/or the environmental
restoration program at Elmendorf, are presented below and have
been paraphrased for greater clarity.
COMMENTS AND USPONSES
1. How were the various sites numbered; does the OU number
correspond with its priority?,

Response: Source areas were numbered in the order they were
discovered. OU numbers do not reflect priority or relative
degree of severity, but are random. OUl was the first to undergo
investigation because of its proximity to Ship Creek and the base
boundary and the uncertainty concerning the type of contaminants
disposed of.
2. Another OU drains into Ship Creek; why not investigate them
together?
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R~sponse: The siLes were grouped separately to make them more
manageable. The cumulative effects of the sites will be
investigated along with the last QU. In addition, a Bioloaical
Technical Assistance Group has been formed to look at impa~ts to
Ship Creek from all sites in the area, not j~st Elmendorf AFE.

3. How does the Air Force allocate funds for the different
sites? How much money was spent in the QUI investigation?
Response: A Defense Priority Model is used to score each site'
based on its potential impact to human health and the ,
environment. Program funding requirements are submitted through
Air Force Channels to the Department of Defense and ultimately
congress along with the relative priority of the site.
Approximately 2 million dollars were spent at QUI.
4. How is a decision made to select an alternative that will not
completely clean up a site?
Response: Alternatives are evaluated based on the nine criteria
discussed in the Proposed Plan and Record of Decision. The
criteria include factors beyond how clean an alternative can get
the site. In the case of CU1, the more "active" alternative
involving in~situ treatment could mobilize other metals making
the situation worse. The preferred alternative is considered to
be protective of human health and the environment.
s. How did the program begin; was the base listed on the
National Priorities List due to QU1 sampling?
Response: The Installation Restoration Program began looking at
environmental impacts from past waste disposal activities in the
early 1980's. This was an Air Force directive implemented across
the country in response to growing awareness of and concern for
environmental quality. Th& base was not listed on the National
priorities List due to sampling conducted at QU1.
6. How old are the landfills and what prompted the Air Force to
start the investigation at QU1?
Response: The QUI landfill sites were operated anywhere from the
early 1950's until the 1983. Due to their age and the lack of
sound waste management practices at that time, there was a high
potential for hazardous wastes having been disposed of in the
landfills. Review of aerial photographs revealed disposal areas
including trenches that may have received liquid waste.
Interviews with people working on and living around the base
during the time the landfills were active further supported the
need for investigation. In addition, a trench well within QU1
that was shut down because it exhibited possible contamination
led to beginning the remedial investigation.
-------
7.
How long has the base been measuring manganese in Ship Creek?
Response: The base has been tracking water quality in Ship Creek
since 1984. Measurements are made three times a year in spring,
summer and fall.
8. How is the deeper aquifer protected when installing a well
through the clay layer that separates it from the shallow,
contaminated aquifer?

Response: When drilling the well a casing ;is '.installed to the
top of the clay layer prior to penetrating the clay. A plug is
put to further ensure no cross contamination. Drilling then
continues through the clay and into the deeper aquifer.
Additional information on construction of monitoring wells is
contained in the Management Plans ,and Remedial
Investigation/Feasibility Study Report for QUl.
9. If the deeper aquifer used for drinking water isn't in
danger, is the potential danger to Ship Creek?
Response: Yes, there is a potential danger to Ship Creek.
Impacts to Ship Creek are being investigated further under QU 6.
Further.more, there is a risk to potential drinkers of the shallow
aquifer. The shallow aquifer is not currently used for drinking
water'and the base prohibits its use for any reason. The
institutional controls being put in place will ensure the shallow
aquifer is not used.
10. What health concerns besides Parkinson's Disease are
associated with mang~ese?
Response: For industrial workers pneumonia or other lung
toxicity problems may be assQciated with inhalation of manganese
dust. There may be other central nervous system effecting
syndromes, similar to Parkinson's, associated with elevated
levels of manganese.
11. Why wasn't a pilot study done to evaluate the in-situ
treatment alternative?
Responses The elevated mangan~se wasn't identified until the
final round of sampling. Only' one well showed manganese at
levels of concern. A pilot study was not warranted at the site.
12.
Has the Air Force found the source of the manganese?
Response: The manganese is elevated as a result of a chemical
process that is initiated by the presence of organic compounds.
The source of the manganese is the natural soil. The source of
the organics could be one or more of the landfill cells at QUI.
-------
13. Alternative 3 has not been adequately characterized based on
the question of State acceptance. It is important to evaluate an
actual cleanup alternative rather than long term monitoring.
Response: Risk was calculated based on a ve~ conservative
scenario (residential land use). Alternative 2, which restricts
land use, is fully protective of human health and the
environment. Treatability studies required to further evaluate
alternative 3 may mobilize other metals in the aquifer causing
additional risks rather than reducing the risk associated with
manganese.
14. The Air Force (Elmendorf) should be more proactive (with its
actions at CU1).
Response: . The Air Force has a proactive program. Part of that
is weighing out all the factors when evaluating a cleanup
alternative. Based on an evaluation of the nine criteria
discussed in the Proposed Plan, the Agencies collectively prefer
limited action with long term monitoring for addressing elevated
levels of manganese in the groundwater underlying CU1.

15. It seems that CU1 is not a big problem, and that the
manganese is contained. It seems that there would have been a
worse site to deal with first.
Response: In the beginning of the investigation, the Air Force
was unsure what degree of contamination would be found. It is
true that the problems at CU1 are relatively mild.
16. The Air Force is talking in terms of risk management when it
should be talking in terms of risk reduction.
Response: Since the risk at CUI is potential rather than
currently existing, risk management and risk reduction are
essentially the same.
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