PB95-964612
EPA/ROD/R10-95/122
May 1996
EPA Superfund
Record of Decision:
U.S. DOE Idaho National Engineering
Laboratory (O.U. 4-12 and 4-03), ID
9/28/1995
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Idaho
National
Engineering
Laboratory
DIVISION OF
ENVIRONMENTAL QUALITY
Record of Decision
Declaration for Central Facilities Area Landfills I, II, and III
(Operable Unit 4-12), and No Action Sites (Operable Unit 4-03)
Idaho National Engineering Laboratory
Idaho Falls, Idaho
Aerial view of Central Facilities Area Landfills I, II, and III
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DECLARATION OF THE RECORD OF DECISION
SITE NAME AND LOCATION
Central Facilities Area Landfills I, n, and IE
Idaho National Engineering Laboratory
Idaho Falls, Idaho
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial action for the Central Facilities Area
(CFA) Landfills I, U, and HI located at the Idaho National Engineering Laboratory (INEL). The
remedial action was chosen in accordance with the Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA) as amended by the Superfund Amendments and
Reauthorization Act (SARA), and is consistent, to the extent practicable, with the National Oil
and Hazardous Substances Pollution Contingency Plan (NCP, 40 CFR Part 300). Information
supporting the selection of the remedy is contained in the Administrative Record for the CFA
Landfills.
The lead agency of this decision is the U.S. Department of Energy (DOE). The U.S.
Environmental Protection Agency (EPA) approves of this decision and, along with the Idaho
Department of Health and Welfare (IDHW), has participated in the evaluation of final action
alternatives. The IDHW concurs with the selection of the preferred remedy for the CFA
landfills.
This decision document also summarizes information on 19 Track 1 investigations (consisting
of underground storage tank sites) designated as "no further action" and documents the "no
further action" decision for these sites.
ASSESSMENT OF THE SITE
Uncertainty associated with hazardous substances potentially disposed in CFA Landfills I, n,
and m may present a potential threat to public health, welfare, or the environment if not
addressed by implementing the response action selected in this record of decision (ROD).
Due to the uncertainty associated with the landfill contents and the need for containment of
the landfill contents, a remedial action of containment is warranted for the site, even though the
risk assessment indicates that the CFA landfills do not currently present an unacceptable risk to
human health or the environment. Implementation of the remedial action selected in this ROD
will provide for containment of the waste with a native soil cover, institutional controls, and
monitoring.
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DESCRIPTION OF THE SELECTED REMEDY
The selected remedy addresses the source of contamination by containing the buried wastes
and contaminated soils. The selected remedy will minimize the CFA landfills as a source of
potential groundwater contamination and reduce potential risks associated with exposure to the
contaminated waste. The selected remedy includes elements that are consistent with EPA's
Presumptive Remedy for CERCLA Municipal Landfill Sites.
The major components of the selected remedy include:
Placement of a native soil cover (in combination with the existing soil cover) to a
minimum depth of 2 ft, compacted and graded to minimize erosion and infiltration by
controlling surface water runon/runoff, resulting from seasonal precipitation.
Implementation of administrative controls on future land use and the posting of signs.
Conducting groundwater, infiltration, and/or vadose zone monitoring to monitor the
effectiveness of the remedial action. A monitoring plan will be developed by the agencies
during the remedial design phase.
Periodically inspecting and maintaining the cover to ensure its integrity.
Maintaining institutional controls, including signs, postings, and land use restrictions.
STATUTORY DETERMINATION
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. Because the wastes can be reliably controlled in place,
treatment of the principal sources of the site was not found to be practicable. Therefore, this
remedy does not satisfy the statutory preference for treatment as a principal element of the
remedy. A remedy in which contaminants could be excavated and treated effectively is precluded
because of the size of the landfills and because there are no known on-site hot spots that
represent major sources of contamination.
Because this remedy will result in potentially hazardous substances remaining in the landfills
on-site, a review will be conducted within 5 years after commencement of the remedial action, and
every 5 years thereafter, to ensure that the remedy continues to provide adequate protection of
human health and the environment
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Signature sheet for the foregoing Central Facilities Area T-anrifilk I, n, and HI at the Idaho
National Engineering Laboratory Record of Decision between the U.S. Department of Energy
and the U.S. Environmental Protection Agency, with concurrence by the Idaho Department of
Health and Welfare.
'ohn M. Wilcynski (j Date
ager
U.S. Department of Energy, Idaho Operations Office
ui
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Signature sheet for the foregoing Central Facilities Area Landfills I, n, and HI at the Idaho
National Engineering Laboratory Record of Decision between the U.S. Department of Energy
and the U.S. Environmental Protection Agency, with concurrence by the Idaho Department of
Health and Welfare.
Chuck Clarke Date
Regional Administrator, Region 10
U.S. Environmental Protection Agency
IV
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Signature sheet for the foregoing Central Facilities Area Landfills I, n, and HI at the Idaho
National Engineering Laboratory Record of Decision between the U.S. Department of Energy
and the U.S. Environmental Protection Agency, with concurrence by the Idaho Department of
Health and Welfare.
Wallace N. Cory f Date
Administrator
Division of Environmental Qua
Idaho Department of Health and Welfare
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CONTENTS
DECLARATION OF THE RECORD OF DECISION i
SITE NAME AND LOCATION i
STATEMENT OF BASIS AND PURPOSE i
ASSESSMENT OF THE SITE i
DESCRIPTION OF THE SELECTED REMEDY ii
STATUTORY DETERMINATION ii
ACRONYMS AND ABBREVIATIONS .... xi
1. SITE NAME AND LOCATION 1
2. SITE HISTORY AND ENFORCEMENT ACT1V111US 3
3. HIGHLIGHTS OF COMMUNITY PARTICIPATION .5
4. SCOPE AND ROLE OF OPERABLE UNIT AND RESPONSE ACTIONS 6
5. SUMMARY OF SITE CHARACTERISTICS 7
5.1 Physical Characteristics of the CFA Landfills 7
5.1.1 Landfill I 7
5.1.2 Landfill H 8
5.13 Landfill m 8
5.2 Landfill Waste Description 8
5.2.1 Landfill I and Subunits 9
5.2.2 Landfill H 13
5.2.3 Landfill m 13
53 Nature and Extent of Contamination 19
53.1 Surface Soil 19
532 Subsurface Soil Sampling of Landfill II..- 19
533 Vadose Zone Soil Gas 22
53.4 Leachate Migration 22
5.3.5 Groundwater 23
53.6 Air ". 25
Vll
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6. SUMMARY OF SITE RISKS 25
6.1 Human Health Risks 25
6.1.1 Identification of Contaminants of Concern 25
6.1.2 Exposure Assessment 26
6.13 Risk Characterization 27
6.1.4 Uncertainty 29
6.2 Environmental Risk Assessment 29
6.2.1 Contaminants of Concern 31
623. Exposure Assessment 31
6.23 Risk Characterization 31
62.4 Conclusions and Limitations 31
7. DESCRIPTION OF ALTERNATIVES 32
7.1 Remedial Action Objectives 32
12 Summary of Alternatives i.... 33
73 Alternative 1 - No Action with Monitoring 35
7.4 Alternative 2 - Institutional Controls with Monitoring 35
15 Alternative 3 - Uniform Containment with Native Soil Cover, Institutional Controls,
and Monitoring 36
7.6 Alternative 4 - Containment with Single-Barrier Cover, Institutional Controls, and
Monitoring 37
8. SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES 38
8.1 Threshold Criteria 38
8.1.1 Overall Protection of Human Health and the Environment 38
8.12 Compliance with ARARs 39
8.2 Balancing Criteria 40
8.2.1 Long-Term Effectiveness and Permanence 40
8.2.2 Reduction of Toxicity, Mobility, or Volume through Treatment 40
823 Short-Term Effectiveness 40
82.4 Implementability 41
Cost 41
vm
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83 Modifying Criteria 41
83.1 State Acceptance 41
8.32 Community Acceptance 41
9. SELECTED REMEDY 42
9.1 Uniform Containment with Native Soil Cover - Description 42
9.2 Estimated Costs for the Selected Remedy 43
10. STATUTORY DETERMINATIONS 43
10.1 Protection of Human Health and the Environment 44
10.2 Compliance with ARARs 44
10.2.1 Chemical-Specific ARARs 44
10.22 Action-Specific ARARs 44
1023 Location-Specific ARARs 44
10.2.4 To-be-Considered Guidance 44
103 Cost-Effectiveness 45
10.4 Use of Permanent Solutions and Alternative Treatment Technologies to the
Maximum Extent Practicable 45
10.5 Preference for Treatment as a Principal Element 45
11. NO ACTION STIES IN OPERABLE UNIT 4-03 46
12. DOCUMENTATION OF SIGNIFICANT CHANGES 49
Appendix A - Responsiveness Summary A-l
Appendix B - Public Comment/Response List Index B-l
FIGURE
1. Location of CFA Landfills I, n, and m at the Idaho National Engineering Laboratory 2
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TABLES
1. Estimated waste volumes for Landfill I, rubble landfill from mid-1950s to 1970 10
2. Estimated waste volumes for Landfill I, rubble landfill from 1982 to 1984 (estimates based
on Landfill I logbook) 11
3. Estimated waste volumes for Landfill I, western waste trench 12
4. Estimated waste volumes for Landfill I, northern waste trench 14
5. Estimated waste volumes for CFA Landfill n 15
6. Estimated waste volumes for CFA Landfill ffl 20
7. Summary of potential carcinogenic risks and noncarcinogenic hazard quotients for CFA
Landfills I, H, and m 28
8. Summary of major uncertainty factors associated with the CFA Landfills baseline risk
assessment 30
9. Summary of ARARs and TBC criteria for CFA landfill alternatives 34
10. CFA landfills alternative cost estimates8 (net present value) 42
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ACRONYMS AND ABBREVIATIONS
ANL-W Argonne National Laboratory-West
ARA Auxiliary Reactor Area
ARARs applicable or relevant and appropriate requirements
BLM Bureau of Land Management
CERCLA Comprehensive Environmental Response, Compensation, and Liability Act
CFA Central Facilities Area
CFR Code of Federal Regulations
COCA Consent Order and Compliance Agreement
cpm counts per minute
CPP Chemical Processing Plant (a.k.a. ICPP)
d day(s)
DOE U.S. Department of Energy
EPA U.S. Environmental Protection Agency
ESRP Eastern Snake River Plain
FFA/CO Federal Facility Agreement/Consent Order
FR Federal Register
FS feasibility study
ft foot (feet)
g gram(s)
gal gallon(s)
HEAST Health Effects Assessment Summary Tables
ICPP Idaho Chemical Processing Plant (a.k.a. CPP)
IDHW Idaho Department of Health and Welfare
in. inch(es)
INEL Idaho National Engineering Laboratory
INWMIS Industrial Nonradiological Waste Management Information System
IRIS Integrated Risk Information System
kg kilogram(s)
L liter(s)
Ib pound(s)
LDU land disposal unit
LEL lower explosive limit
LOFT Loss-of-Fluid Test Facility
MCL maximum contaminant level
mg milligram(s)
mg/kg-d milligrams per kilogram day
mi mile(s)
NCP National Contingency Plan
NPL National Priorities List
NRF Naval Reactors-Facility
NWT northern waste trench
OU operable unit
pCi picocurie(s)
PBF Power Burst Facility
PAH polycyclic aromatic hydrocarbon
xi
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ppm parts per million
RAOs remedial action objectives
RCRA Resource Conservation and Recovery Act
RED reference dose
RI/FS remedial investigation/feasibility study
RME reasonable maximum exposure
ROD record of decision
RWMC Radioactive Waste Management Complex
SARA Superfund Amendments and Reauthorization Act
SF slope factor
SRPA Snake River Plain Aquifer
SWMU solid waste management unit
TAN Test Area North
TBC to be considered
TRA Test Reactor Area
UCL upper confidence limit
WAG waste area group
WRTF Water Reactor Test Facility
WWT western waste trench
yd3 cubic yard(s)
yr year(s)
Mg microgram(s)
xu
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Decision Summary
1. SITE NAME AND LOCATION
Central Facilities Area Landfills I, n, and in (Operable Unit 4-12)
and No Action Sites (Operable Unit 4-03)
Idaho National Engineering Laboratory, Idaho Falls, Idaho
The Idaho National Engineering Laboratory (INEL) is a government-operated facility
managed by the U.S. Department of Energy (DOE). The INEL is located 42 mi west of Idaho
Falls, Idaho, and occupies 890 mi2 of the northeastern portion of the Eastern Snake River Plain
(ESRP). The INEL encompasses portions of five Idaho counties: Butte, Jefferson, Bonneville,
Clark, and Bihgham. Public access to the INEL is limited to two Federal highways and three
state highways that intersect the Site. The Central Facilities Area (CFA) is located in Butte
county in the south-central portion of the INEL, approximately 50 mi from the larger
southeastern Idaho cities of Idaho Falls and Pocatello. CFA Landfills I, n, and ffl are located
approximately 0.5 mi north of CFA proper (Figure 1).
Current land use at the INEL is primarily nuclear research and development and waste
management Surrounding areas are managed by the Bureau of Land Management (BLM) for
multipurpose use. The developed area within the INEL is surrounded by a 500-mi2 buffer zone
used for cattle and sheep grazing. Of the 10300 people employed at the INEL, approximately
1,100 are located at CFA. The nearest off-site populations are in Atomic City (7 mi southeast of
CFA), Arco (17.5 mi west of CFA), Howe (15 mi northwest of CFA), Mud Lake (32 mi northeast
of CFA), and Terreton (33 mi northeast of CFA).
The INEL property is located on the northeastern edge of the ESRP, a volcanic plateau that
is primarily composed of volcanic rocks and relatively minor amounts of sedimentary interbeds.
The basalts immediately below the CFA are relatively flat, and are covered by 20 to 30 ft of
alluvium.
The depth to the Snake River Plain Aquifer (SRPA) underlying the INEL varies from 200 ft
in the northern portion to 900 ft in the southern portion. The depth to the SRPA at CFA is
about 480 ft Flow of the aquifer in this region is generally to the south-southwest
The INEL has semidesert characteristics with hot summers and cold winters. Normal annual
precipitation is 9.1 in./yr, with estimated evapotranspiration of 6 to 9 in./yr. The only surface
water present at the INEL is the Big Lost River, which is approximately 13 mi northwest of the
CFA landfills at its nearest point Due to irrigation diversions upstream and semi-arid climate,
the river is typically dry. The only naturally occurring surface water at CFA results from heavy
rainfall or snowmelt, usually during the period from January to April.
Twenty distinctive vegetative types have been identified at the INEL. Big sagebrush is the
dominant species, covering approximately 80% of the ground surface. The variety of habitats on
the INEL support numerous species of reptiles, birds, and mammals. Several bird species at the
INEL that warrant attention because of sensitivity to disturbance or their threatened status
1
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To Salmon Vy
K>
To Test Area North
and m. 33
FA Landfill III
CFA Landfill II
CFA Landfill I
Scoville
power
station
Central
Facilities
Area
To m. 2W28
andArco, ID
Central Facilities Area
(CFA)
To main gate
Rt. 20 and 26
0 _400 800
Scale In ft
R950290
Figure 1. Location of CFA Landfills I, II, and III at the Idaho National Engineering Laboratory.
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include the ferruginous hawk (Buteo regalis), bald eagle (Haliaeetus leucocephalus), long-billed
curlew (Numerous americanus), and the loggerhead shrike (Lanius Ludovicianus). In addition,
the Townsend's big-eared bat (Plecotus Townsendii) and pygmy rabbit (Brachylagus Idahoensis)
are listed by the U.S. Fish and Wildlife Service as candidates for consideration as threatened or
endangered species. The ringneck snake, whose occurrence is considered to be INEL-wide, is
.listed by the Idaho Department of Fish and Game as a Category C sensitive species.
CFA Landfill I was operated as a disposal facility from the early 1950s until the mid 1980s.
The landfill covers a total surface area of approximately 8.25 acres. The landfill is composed of
three major units, commonly referred to as the nibble landfill, the western waste trench, and the
northern waste trench. CFA Landfill H, in use from 1970 until 1982, was a fill operation
encompassing 15 acres in the southwestern portion of an abandoned gravel pit. CFA Landfill ID,
encompassing 12 acres, was opened in October of 1982, when operations at CFA Landfill n were
terminated, and continued as a cut-and-CIl operation until December 1984 when it also was
terminated. An expansion to Landfill HI was opened west of the original Landfill III and
continued to handle the same types of waste. It was operational until 1993 and is no longer in
use. This expansion to Landfill IE is not considered part of OU 4-12 because it was still
operational when this investigation began, and therefore is outside the scope of this ROD. All
further references to Landfill ffl refer to that portion of Landfill ffl (original six trenches)
operational prior to December 4, 1984.
The predominant waste types entering the landfills were construction, office, and cafeteria
waste. Review of the waste inventory records indicate that the major types of waste accepted at
the landfills include trash sweepings, cafeteria garbage, wood and scrap lumber, masonry concrete,
scrap metal, weeds and grass, din and gravel, asphalt, and asbestos. To a lesser extent, potentially
hazardous wastes were also disposed to the landfills such as waste oil, solvents, chemicals, and
paint. Information regarding the types and amounts of potentially hazardous wastes disposed to
the landfills is not complete due to incomplete waste disposal inventory records.
2. SITE HISTORY AND ENFORCEMENT ACTIVITIES
The original facilities at CFA were built in the 1940s and 1950s to house Naval Gunnery
Range personnel. The facilities have been modified over the years to fit the changing needs of
the INEL and now provide four major types of functional space: craft, office, service, and
laboratory. The CFA landfills were operated as municipal-type landfills for the INEL from the
early 1950s until the mid 1980s.
The Resource Recovery Act (enacted in 1970) initially governed the landfill activities. In
1976, the Resource Conservation and Recovery Act (RCRA) was enacted, with subsequent
regulations governing landfills promulgated in 1980. A Consent Order and Compliance
Agreement (COCA) was signed by DOE, the U.S. Geological Survey, and the U.S. Environmental
Protection Agency (EPA) in 1987 that specified a RCRA corrective action program for INEL
solid waste management units (SWMUs) under RCRA authority. A key element of the COCA
was the identification of all known SWMUs within the INEL, including a specific subset
designated as land disposal units (LDUs). SWMUs at the INEL were identified as LDUs if it was
known or strongly suspected that RCRA hazardous wastes or radioactive-RCRA hazardous wastes
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(mixed wastes) were managed or placed at the unit in a manner constituting land disposal after
the cutoff date of November 19,1980. CFA Landfill I was classified as a SWMU because it was
suspected that RCRA hazardous wastes were not routinely disposed after the cutoff date. CFA
Landfills n and HI were identified as LDUs because it was suspected that hazardous wastes were
disposed after the cutoff date.
On July 14,1989, EPA proposed placing the INEL on the National Priorities List (NPL) of
the National Contingency Plan (NCP) (54 FR 29820) (EPA, 1990a). This was done using Hazard
Ranking System procedures found in the NCP. The INEL's score was 51.91 (sites scoring 28.5 or
greater are eligible for the NPL) based in part on releases of contaminants to the groundwater at
two faculties: Test Reactor Area (TRA) and Test Area North (TAN). Data that support listing
the INEL as an NPL site are found in the Federal Facilities Docket, EPA Headquarters,
Washington, D.C. After considering public input during a 60-day comment period following the
proposed INEL listing, EPA issued a final rule listing the INEL Site. The rule was published in
the Federal Register (FR 29820), November 21,1989.
Subsequent to listing the INEL on the NPL and with the development of the Federal Facility
Agreement/Consent Order (FFA/CO) and the Action Plan (effective date December 9,1991),
DOE, EPA, and the Idaho Department of Health and Welfare (IDHW) decided that the CFA
landfills should be evaluated under the authority of the Comprehensive Environmental Response,
Compensation, and Liability Act (CERCLA). The status of LDUs was discussed in detail among
DOE, EPA, and IDHW during the initial negotiations of the FFA/CO in 1991, and rationale for
^classifying LDUs to SWMUs was made. The results of the negotiations are summarized in a
letter from DOE to IDHW and finalized in the FFA/CO. Under the new guidelines, a unit
retained its RCRA LDU designation only if known RCRA hazardous waste was routinely or
systematically disposed after November 19,1980. Consequently, many units lost their RCRA
LDU status if disposal of RCRA hazardous waste was a one-time event or where knowledge of
the event was based on conjecture or hearsay. Landfills n and HI lost their LDU status based on
this rationale.
With respect to Landfill L investigation conducted during the RI revealed a logbook
maintained by landfill operators that contained disposal records for waste disposed to Landfill I
from 1981 through 1984. Review of this logbook indicated that the major types of waste accepted
at this landfill during that time period included trash sweepings, cafeteria garbage, wood and scrap
lumber, masonry concrete, scrap metal, weeds and grass, dirt and gravel, asphalt, and asbestos. To
a lesser extent, potentially hazardous wastes were also disposed to the landfill such as paint,
resins, sludge, and chemicals. However, because there was no conclusive evidence that RCRA
hazardous wastes were disposed to Landfill I after November 19,1980, Landfill I was not
classified as a RCRA LDU.
A Track 2 investigation was performed on Landfill I under the FFA/CO. A recommendation
was made in the Track 2 investigation to further evaluate the groundwater and air pathways of
Landfill I as part of the OU 4-12 Remedial Investigation/Feasibility Study (RI/FS). The primary
source of information on Landfill I is the Preliminary Scoping Track 2 Summary Report for
Operable Unit 4-10 (Trippet et at, 1995). A copy of this report can be found in the
Administrative Record for Waste Area Group (WAG) 4. This ROD documents the results of the
RI/FS and the selected remedy for CFA Landfills I, n, and HI.
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3. HIGHLIGHTS OF COMMUNITY PARTICIPATION
In accordance with CERCLA § 113(k)(2)(B)(i-v) and 117, a series of opportunities for public
information and participation in the remedial investigation and decision process for the CFA
landfills were provided to the public from August 1993 through May 1995. For the public, the
activities ranged from receiving a fact sheet that briefly discussed the CFA landfills investigation
to date, INEL Reporter articles and updates, and a proposed plan, to conducting a telephone
briefing and public meetings.
In August 1993, a fact sheet concerning the CFA landfills remedial investigation was sent to
about 6,700 individuals of the general public and 650 INEL employees on the INEL Community
Relations Plan mailing list.
Informal open house meetings on the CFA landfills remedial investigation were held August
11 and 12,1993, in Pocatello and Twin Falls, respectively. Public information meetings on the
CFA landfills remedial investigation were also held on August 17, 18, and 19, 1993, in Idaho Falls,
Boise, and Moscow, respectively. During these meetings, representatives from DOE and INEL
discussed the project, answered questions, and listened to public comments. Comments from the
information meetings were evaluated and considered as part of the RI/FS process.
Regular reports concerning the status of the CFA landfills project were included in the INEL
Reporter and mailed to those who attended the meetings and who were on the mailing list.
Reports appeared in six issues of the INEL Reporter and three Citizens' Guides.
In April 1995, a fact sheet concerning the CFA landfills was sent to about 6,700 individuals of
the general public and 650 INEL employees on the INEL Community Relations Plan mailing list.
On April 11, 1995, the DOE issued a news release to more than 100 news media contacts
concerning the beginning of a 30-day public comment period, which began April 26, 1995 and
ended May 26,1995, pertaining to the CFA Proposed Plan. Both the fact sheet and news release
gave notice to the public that CFA documents would be available before the beginning of the
comment period in the Administrative Record section of the INEL information repositories
located in the INEL Technical Library of Idaho Falls, the INEL Boise Office, as well as in public
libraries in Idaho Falls, Fort Hall, Pocatello, Twin Falls, Boise, and Moscow.
Opportunities for public involvement in the decision process for the CFA landfills were
provided beginning in April 1995. For the public, the activities ranged from receiving the
proposed plan, conducting one teleconference call, and attending open houses and public
meetings to informally discuss the issues and offer verbal and written comments to the agencies
during the 30-day public comment period.
Copies of the proposed plan for the CFA landfills were mailed to about 6,700 members of the
public and 650 INEL employees on the INEL Community Relations Plan mailing list on April 24,
1995, urging citizens to comment on the proposed plan and to attend public meetings. Display
advertisements announcing the same information and the location of public meetings on May 16,
17, and 18,1995, in Idaho Falls, Boise, and Moscow, respectively, appeared in seven major Idaho
newspapers. Large advertisements appeared in the following newspapers on April 26: Post
Register (Idaho Falls); Idaho State Journal (Pocatello); South Idaho Press (Burley); Times News
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(Twin Falls); Idaho Statesman (Boise); Lewiston Morning Tribune (Lewiston); and The Daily News
(Moscow).
A post card was mailed on May 10, 1995, to about 6,700 members of the public and 650 INEL
employees on the INEL Community Relations Plan mailing list to encourage them to attend the
public meetings and provide verbal or written comments. Both media, the news release and
newspaper advertisements, gave public notice of public involvement activities and offerings for
briefings, and the beginning of a 30-day public comment period that was to begin April 26 and
run through May 26,1995.
Written comment forms, including a postage-paid business reply form, were made available to
those attending the public meetings. The forms were used to turn in written comments at the
meeting and, by some, to mail in comments later. For those who did not attend the public
meetings but wanted to make formal written comments, a written comment form was attached to
the Proposed Plan. The reverse side of the meeting agenda contained a form for the public to
evaluate the effectiveness of the meetings. A court reporter was present at each meeting to keep
verbatim transcripts of discussions and public comments. The meeting transcripts were placed in
the Administrative Record section for the CFA landfills, Operable Unit (OU) 4-12, in eight INEL
information repositories.
A total of about 10 people (other than agency representatives) attended the CFA landfills
public meetings. Overall, eight provided formal comment; of these eight people, three provided
oral comments and five provided written comments. All comments received on the proposed plan
were considered during the development of this ROD. The decision for this action is based on
the information in the Administrative Record for this OU.
A Responsiveness Summary has been prepared as part of the ROD. All formal verbal
comments, as given at the public meetings, and all written comments, as submitted, are repeated
verbatim in the Administrative Record for the ROD. Those comments are annotated to indicate
which response in the Responsiveness Summary addresses each comment
On August 2,1995, project managers from the Idaho Department of Health and Welfare
Division of Environmental Quality gave a brief presentation on the project to the Environmental
Management Site Specific Advisory BoardINEL. The advisory board is a group of individuals
representing the citizens of Idaho, making recommendations to DOE, EPA, and the state of
Idaho regarding environmental restoration activities at the INEL.
4. SCOPE AND ROLE OF OPERABLE UNIT
AND RESPONSE ACTIONS
Under the FFA/CO, the INEL is divided into ten WAGs. The WAGs are further divided into
OUs. The CFA has been designated WAG 4, and consists of 13 OUs. OU 4-12 consists of the
wastes disposed to the three landfills and the associated soil impacted by the landfills. Data from
shipping records, along with process knowledge, written correspondence, and interviews with
current and previous employees, and monitoring and sampling data were used to evaluate the
CFA landfills OU 4-12.
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A complete evaluation of all cumulative risks associated with CERCLA actions at WAG 4 will
be conducted as part of the WAG 4 Comprehensive RI/FS (OU 4-13) to ensure that all risks
have been adequately evaluated.
5. SUMMARY OF SITE CHARACTERISTICS
The following sections provide a summary of the physical characteristics of the CFA landfills
as well as a description of the wastes disposed to the landfills, and a summary of the contaminants
present in various media associated with the landfills. Greater detail may be found in the
"Remedial Investigation/Feasibility Study for Operable Unit 4-12: Central Facilities Area
Landfills I, n, and IE at the Idaho National Engineering Laboratory."
5.1 Physical Characteristics of the CFA Landfills
The CFA landfills are located on the ESRP in Big Lost River alluvial deposits overlying basalt
bedrock. The sediments comprising these deposits are primarily sands and gravels and contain
very few fine-grained materials. In some places, however, a clay-rich layer (0 to 9 ft thick) exists
above the bedrock. Depth to basalt at these landfills ranges from 10 to 37 ft The vadose zone,
that portion of the subsurface that extends from the land surface down through the subsurface to
the water table, at the CFA landfills is approximately 480 ft thick. It is composed of a relatively
thin layer of surface sediments, in which the wastes are disposed, and thick sequences of
interfingering basalt flows containing interbedded sediments. As a result of the relatively low
annual precipitation, high potential evapotranspiration, and deep water table, vadose zone soils at
the landfills tend to be relatively dry during most of the year. The SRPA, one of the largest and
most productive groundwater resources in the United States, underlies the CFA landfills. The
aquifer is listed as a Class I aquifer, and EPA has recently designated it as a sole source aquifer.
The SRPA consists of a series of saturated basalt flows and interlayered pyroclastic and
sedimentary materials that underlie the ESRP. The depth to water at the CFA landfills varies
from about 476 ft to just over 495 ft The direction of groundwater flow in this general vicinity is
in a south to southwesterly direction.
5.1.1 Landfill I
Landfill I occupies a total surface area of approximately 8.25 acres, and consists of three
subunits: the nibble landfill, western waste trench, and northern waste trench. The rubble landfill
originated as a gravel quarry that was operated by the U.S. Navy from 1942 to 1949. The quarry
was used as a disposal area for Site-wide waste disposal sometime after 1949. The surface area of
the rubble landfill is estimated to be 5.5 acres, and its depth is estimated to be 12 to 15 ft. The
rubble landfill is covered with approximately 1 to 5 ft of soil overlain with a layer of gravel. The
surface of the western waste trench is approximately 2 acres, consisting of smaller waste trenches,
each excavated to a size of 8 ft wide by 10 ft deep by 50 ft long. Each of the smaller trenches is
separated from the other by 15 ft of undisturbed soil. Filled trenches were covered with 1 to 5 ft
of soil. The northern waste trench was identified from aerial photographs and has a surface area
of approximately 0.75 acres. Information pertaining to its true dimensions is limited. Currently, it
is covered with soil and is undiscernible at the surface.
-------
5.1.2 Landfill II
Landfill n encompasses approximately 15 acres and is located in the southwest corner of an
abandoned gravel pit Depth to basalt at the landfill varies from 15 to 37 ft based on a seismic
refraction survey and a subsurface borehole drilling investigation. The landfill waste profile,
however, is estimated to range in depth from 12 to 28 ft because the pit probably was not
excavated beyond the base of the gravel-bearing unit and into the clay material. Hand augering at
60 sampling sites indicated that the Landfill n soil cover ranges in thickness from 0.33 to 3.17 ft,
with an overall mean of 1.50 ft The landfill surface is gently undulating due to differential
settling of the waste and maintains a stand of crested wheatgrass.
5.1.3 Landfill III
Landfill m consists of six trenches that cover approximately 12 acres. Depth to the
underlying basalt is 10 to 33 ft based on a seismic refraction survey. The landfill waste profile is
estimated to be 13 ft deep on average. It was common practice to excavate the landfill trenches,
leaving a soil layer intact between the waste and underlying basalt. The Landfill HI soil cover
ranges in thickness from 1 to 8 ft with an overall mean of 2.83 ft, based on augering results.
Ground-penetrating radar measurements indicate the average soil cover thickness to be 2 to 3 ft
The landfill surface is also gently undulating due to differential settling of the waste and maintains
a stand of crested wheatgrass.
5.2 Landfill Waste Description
Contaminant sources in the CFA landfills can be generally described as solid and liquid
nonradioactive materials disposed to the landfills over the past 40 years. The predominant waste
types entering the landfills were construction, office, and cafeteria waste. Review of the waste
inventory records indicate that the major types of waste accepted at the landfills include trash
sweepings, cafeteria garbage, wood and scrap lumber, masonry concrete, scrap metal, weeds and
grass, dirt and gravel, asphalt, and asbestos. To a lesser extent, potentially hazardous wastes were
also disposed to the landfills and may include waste oil, solvents, chemicals, and paint Landfill
waste descriptions have been determined from the Industrial Nonradioactive Waste Management
Information System (INWMIS), interviews with site personnel, reports, and other information
related to waste disposal Many uncertainties (especially with Landfill I) are associated with the
data gathered from these sources, including lost or unreadable records, overestimation and/or
underestimation of waste volumes, and inconsistency in actual disposal locations. Although the
reliability of the waste descriptions may not be very high, the waste descriptions do indicate the
general categories of waste typically disposed to these landfills.
Solid nonradioactive materials disposed in the CFA landfills were generated by INEL facilities
including the following: Argonne National Laboratory-West (ANL-W), Auxiliary Reactor Area
(ARA), CFA, Idaho Chemical Processing Plant (ICPP), Experimental Breeder Reactor n, Naval
Reactors Facility (NRF), Special Power Excursion Reactor Test, TAN, and TRA. Material was
collected by the Central Facilities Maintenance Branch of the Site Services Division. Demolition
and construction materials were disposed to the landfill directly by subcontractors responsible for
a given project Records show no indication of material segregation within the landfills. To a
lesser extent, the disposal of liquid wastes in a sludge form, including oils, solvents, and other
8
-------
chemicals did occur, usually by spreading upon the day's collection of solid wastes, compacting,
and covering with at least 1 ft of natural soil cover. During operation of CFA Landfills n and III
(1970 to 1984), screening procedures were in place to prevent radioactive wastes from being
inadvertently deposited in the landfills during their operation. Screening was the responsibility of
the generating facility. Prior to disposal of any waste material at the CFA landfills, the waste was
screened by a radiological control technician for beta- and gamma-emitting radionuclides and for
alpha-emitting radionuclides to determine if the waste material was above radioactive background
levels. However, it is acknowledged that up to one shipment per month containing low levels of
radioactive waste may have been inadvertently disposed to the landfills; wastes were not screened
for radioactivity at the time of disposal on a full-time basis at INEL landfills until 1989.
5.2.1 Landfill I and Subunfts
This section discusses the waste disposal practices at Landfill I, which consists of three
subunits: rubble landfill, western waste trench, and northern waste trench. Estimates of waste
volume and type were made from the landfill logbooks, interviews with site personnel, and
INWMIS, assuming the waste characteristics were similar for Landfill I to those recorded for
Landfills n and HI, since INWMIS does not contain information regarding disposals to Landfill I.
Rubble Landfill. The nibble landfill originated as a gravel quarry that was operated by the
U.S. Navy from 1942 to 1949. In 1949, construction of the National Reactor Testing Station (now
the INEL) began, and the quarry continued to be used as a gravel source. The quarry was used
as a disposal area for Site-wide solid waste sometime after 1949. Waste disposal practices at the
nibble landfill consisted of disposal of waste to the open gravel quarry, infrequent compaction
with earth-moving equipment, and covering with available soil material. Soil covering was not
performed consistently and probably only when areas were filled with waste. It is also known,
based on interviews with knowledgeable personnel, that open burning of flammable wastes
occurred before covering. Additionally, landfill personnel would use disposed flammable liquids to
ignite wastes.
An incinerator, located adjacent to the landfill, operated from 1951 to 1957. It was used to
incinerate classified documents and other paper waste. Paper waste was brought to the
incinerator by truck and was burned. The waste ash was disposed to the rubble landfill.
Review of landfill disposal logbooks indicate that disposal of wastes also occurred from late
1981 through 1984 in the rubble landfill in an area known to workers at the time as the "east
hole." The "east hole" is. an L-shaped pit located within the rubble landfill south of the quarry
spoil pile. It was noted during personnel interviews that a dumping area for several empty acid
storage tanks referred to as the "acid pit" was also located in this area. Interviews with personnel
indicate that the Navy disposed of waste, including shell casings, in the north end of the rubble
landfill. Tables 1 and 2 summarize the wastes including volume estimates by waste types disposed
to the rubble landfill for the periods from the 1950s to 1970 and from 1982 to 1984, respectively.
Western Waste Trench. Waste disposal practices at the western waste trench (WWT)
consisted of disposal of waste to an open area of six smaller trenches. The waste was ignited
inside the trench and covered with soil periodically. According to interviews with site personnel,
flammable liquids were used to improve combustion of wastes. Table 3 summarizes the wastes
including volume estimates by waste types disposed to the western waste trench of CFA Landfill I.
-------
Table 1. Estimated waste volumes for Landfill I, rubble landfill from mid-1950s to 1970.
Waste type
1. Trash, sweepings
2. Cafeteria Garbage
3. Wood, scrap lumber
4. Masonry, concrete
5. Scrap metal
6. Weeds, grass, trees
7. Dirt, gravel
8. Asphalt
9. Asbestos
10. Other
Percent of
total
volume
0%
0%
5%
85%
5%
1%
1%
1%
1%
1%
Total
volume
(yd3)
0
0
6,550
111389
6,550
1308
1,308
1308
1,308
1308
Assumptions
Trash and sweepings were burned
openly in WWT or NWT
Cafeteria garbage was primarily
disposed in WWT or NWT
Wood and scrap lumber were burned
openly or salvaged by employees
Primary waste disposed from
construction and demolition projects
Waste disposed from construction and
demolition projects
Same percentage of total volume as
Landfill E
Similar percentage of total volume as
Landfill n and process knowledge
Same percentage of total volume as
Landfill n
Same percentage of total volume as
Landfill n
Same percentage of total volume as
Landfill
Waste oil, waste oil sludge,
liquid wastes including paint
thinner, paint, solvents
This type of waste was not disposed to
the nibble landfill according to site
personnel. Waste oil was burned
openly, used for dust suppression on
roads, or disposed to the WWT or
NWT according to interviews with site
personnel. Liquid (i.e., solvent waste)
was burned in the WWT and NWT.
Fire extinguishers Unknown Unknown Fire extinguishers were disposed to
(1,1,2-trifluorotrichloroethane) rubble landfill according to interviews
with site personnel.
10
-------
Table 2. Estimated waste volumes for Landfill I, rubble landfill from 1982 to 1984 (estimates
based on Landfill I logbook).
Total volume
Waste type (yd3)
1. Trash, sweepings 1,229
2. Cafeteria garbage 57
3. Wood, scrap lumber 5,444
4. Masonry, concrete 3,730
5. Scrap metal 213
6. Weeds grass, trees 180
7. Dirt, gravel 1,610
8. Asphalt 4,047
9. Asbestos 43
10. Other 134
Boxes of hazardous material 37
Sludge 10
Slag 2
Conductors 4
Tires 10
Resins 4
Lagging 11
Barrels/buckets/dnims 248
Roofing 133
Insulation 306
Gilsolate/gilsotherm 9
Paint 28
Acid tanks 2 empty tanks
Rocks 87
Sodium nitrate 2
Calcium nitrate 2
Sump sludge 2
11
-------
Table 3. Estimated waste volumes for Landfill I, western waste trench.
Waste type
Percent of Total volume
total volume (yd3)
Assumptions
1. Trash, sweepings 74%
2. Cafeteria garbage 11%
3. Wood, scrap lumber 0%
4. Masonry, concrete 0%
5. Scrap metal 0%
6. Weeds, grass, trees <1%
7. Dirt, gravel 2%
8. Asphalt 0%
9. Asbestos <1%
10. Other 1%
Waste oil, waste oil 10%
sludge, paint thinner,
paint, solvents
7,026 Same percentage of total volume as
Landfill n
1,045 Same percentage of total volume as
Landfill H
0 Disposed to rubble landfill
0 Disposed to nibble landfill
0 Disposed to nibble landfill
95 Same percentage of total volume as
Landfill n
190 Same percentage of total volume as
Landfill n
0 Disposed to nibble landfill
95 Same percentage of total volume as
Landfill n
95 Same percentage of total volume as
Landfill n
850 Waste oil was burned openly, used
for dust suppression on roads, or
disposed to the WWT or NWT
according to interviews with site
personnel. Liquid (i.e., solvent
waste) was burned in the WWT and
NWT.
12
-------
Northern Waste Trench. Information on disposal practices for the northern waste trench
(NWT) is not available; however, practices were probably similar to that of the WWT. Table 4
summarizes the wastes including volume estimates of waste types disposed to the NWT of CFA
Landfill I.
5.2.2 Landfill II
Landfill II operated from September 1970 to September 1982. It occupies the southwest
corner of an existing gravel pit that opened in the early 1950s. Waste disposal began in
September of 1970 in the far southwest corner of the pit. It was standard practice for a single
operator to be assigned to the landfill during the day to receive and log in waste. Waste was
placed in the landfill randomly or in "low spots" and was then compacted by a D-8 caterpillar
tractor into layers or cells that were 12 to 24 in. thick. The compacted waste was covered with
approximately 1 ft of coarse soil material (sandy gravel) at the end of the day. Material for the
intermediate cover was scraped from the bottom of the pit and from a previously unexcavated
area north of the landfill. After the landfill operation ceased, overburden material, previously
stockpiled during the opening of the pit, was used for cover material.
During the early 1970s, asbestos was placed in the bottom of the pit at Landfill H The
asbestos was normally covered with waste and then covered with fill material at the end of the
day. By the late 1970s, disposal practices for asbestos were modified to require double bagging or
boxing. According to site personnel, solvent sludges and chemical wastes were disposed at the
landfill. These materials may have been absorbed onto rags and containerized or dumped directly
onto the day's collection of solid waste. Personnel interviews also indicate that most of the drums
disposed to the landfill were empty, occasionally, however, drums containing material (soaked rags
and/or diatomaceous earth) were also disposed. Waste oils were disposed in the landfill; however,
according to the personnel interviews, a significant amount of the waste oil was used on the roads
for dust suppression throughout the 1970s and 1980s. Cooling tower wood from the Materials
Test Reactor at the TRA potentially contaminated with chromates was also disposed in the
landfill. According to personnel interviews, there was no open burning of wastes in Landfill n.
Table 5 summarizes the wastes including volume estimates by waste types disposed to CFA
Landfill n.
5.2.3 Landfill III
Landfill in opened in October 1982 after Landfill n was closed, and operated as a cut-and-fill
trench until December 1984. Waste was placed in the six trenches as they were excavated. The
eastern-most trench was the first to be excavated and was started from the south end with a
trench 24 ft wide. The excavation proceeded from south to north on the first trench with
overburden material being pushed to the sides. Excavation of the second trench then proceeded
from north to south again with the overburden material being pushed to the sides. All six
trenches in the landfill were excavated in this manner.
The logbook maintained by landfill personnel was reviewed to provide insight into the types of
waste and disposal point locations in Landfill HI. Similar to Landfill n, personnel interviews
indicate that no open burning of waste in Landfill HI was conducted. For the most part, asbestos
was placed in the "asbestos pit" immediately north of Landfill IE rather than in the Landfill HI
13
-------
Table 4. Estimated waste volumes for Landfill I, northern waste trench.
Waste type
Percent of
total volume
Total volume
(yd3)
Assumptions
1. Trash, sweepings
2. Cafeteria garbage
3. Wood, scrap lumber
4. Masonry, concrete
5. Scrap metal
6. Weeds, grass, trees
7. Dirt, gravel
8. Asphalt
9. Asbestos
10. Other
Waste oil, waste oil
sludge, liquid wastes
including paint thinner,
paint, and solvents
74%
11%
0%
0%
0%
1%
2%
4,862
772
0
0
0
65
131
0%
1%
1%
10%
0
65
65
588
Same percentage of total volume as
Landfill n
Same percentage of total volume as
Landfill H
Disposed to rubble landfill
Disposed to rubble landfill
Disposed to rubble landfill
Same percentage of total volume as
Landfill n
Same percentage of total volume as
Landfill n
Disposed to rubble landfill
Same percentage of total volume as
Landfill n
Same percentage of total volume as
Landfill n
Waste oil was burned openly, used
for dust suppression on roads, or
disposed to the WWT or NWT
according to interviews with site
personnel. Liquid (i.e., solvent
waste) was burned in the WWT and
NWT.
14
-------
Table 5. Estimated waste volumes for CFA LandGIl IL
INWMIS waste
category
1. Trash and
sweepings
2. Cafeteria
garbage
3. Wood and scrap
lumber
4. Masonry,
concrete
5. Scrap metal
6. Weeds, grass,
trees
7. Dirt, gravel
8. Asphalt
9. Asbestos
Type of waste
- Office trash, paper,
cardboard, plastic,
glass, etc
- Used grease
- Soybean oil
- Vegetable oil
- Food waste
- Up to 70% moisture
- Wood and scrap
lumber
- Scrap lumber
- Used masonry
- Used concrete
Scrap metal
Scrap metal from
welding, pipe fitting
- Sheet metal
operations
- Metal vehicle parts
including wheels,
mufflers, bearings,
vehicle batteries, etc.
- Weeds, grass, and
trees from landscape
maintenance
operations
- Din, gravel
- Used asphalt
- Asbestos
- Asbestos coated
materials such as
pipes, etc
Source
- INEL Facilities,
dumpster
containers
- ANL.CFA,
CPP, NRF,
RWMC, TAN,
TRA
- INEL Facilities,
dumpster
containers
- ANL.ARA
CFA, CPP,
NRF, PBF,
RWMC, TAN,
TRA, WRTF
- ANL.ARA
CFA, CPP,
NRF, PBF,
RWMC, TAN,
TRA, WRTF
- ARA,CFA,
CPP, NRF,
RWMC, TRA
- ARA.CFA,
CPP, NRF,
PBF, TRA
- ANL,ARA,
CFA, CPP,
NRF, PBF,
TRA
- ANL.CFA,
NRF, PBF,
TAN, TRA
Solid Solid
volume weight
(yd3) 0b)
285308
40,528
19,078
17,637
7,154
435
6,415
2,103
807
Liquid
volume
(gal)
275
15
-------
Table 5. (continued).
INWMIS waste
category
Type of waste
Source
Solid
volume
(yd3)
Solid
weight
Liquid
volume
(gal)
10. Other
- Asphalt and din
- Asphalt and concrete
- Asphalt and gravel
- Asphalt, dirt, and
concrete
Asphalt, grass, and
din
Asphalt, ground, sod,
and rock
- CFA, NRF
- ANL
- NRF.TRA
- NRF
- CFA
- NRF
973
19
20
20
28
- Barrels, crates
Buckets
Building material
Cans and bottles
- Construction
materials
- Construction waste
- Dead deer
- Dirt and rock(s)
- Dirt barrels
- Dirt, logs
- Grass, weeds, and
roofing material
Hyplon
Lumber and concrete
Mixed gravel and
scrap metal
Paper, barrels, and
tire
Plants, dirt, and
concrete
Siding
- CPP
- CPP
- NRF
- CFA
- NRF
- NRF
- TRA
- CFA,RWMC
- CPP
- PBF
- CFA
- NRF
- NRF
- RWMC
- TRA
- NRF
- ANL
6
11
1
1
129
3,014
1
105
130
5
66
1
6
7
1
6
2
16
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Table 5. (continued).
INWMIS waste
category
Type of waste
Sod and din
- Soot, rocks, and
Source
- TRA
- PBF
Solid
volume
(yd3)
26
20
Solid
weight
(Ib)
Liquid
volume
(gal)
96. Oil
97. Solvents
98. Chemicals
roofing materials
- Structure consisting TRA
of wood, metal, and
glass
- Tar, buckets, plastic, - ANL
and metal
24
- Unknown (not
specified)
- Visqueen, dirt
- Weeds, dirt
Weeds, grass, asphalt,
and dirt
- Weeds, barrels
- Waste oil sludge
- Waste oil sludge and
scrap
- Carbon tetrachloride
Paint
Paint thinner
Solvents
Asphalt lead
Antifreeze absorbed
on Oil Dri
Beryllium chips
Boric acid
Boron solution
Calcium chloride
Calcium hypochlorite
Chemicals
- ARA.CFA,
CPP.TAN
- CPP
. CPP
- CFA
- CPP
- NRF
- NRF
- NRF
- NRF
- NRF
- NRF
- CPP
- ANL
- TAN
- ANL
- NRF
- CFA
- CFA
- NRF
265
7
5
48
4
4,790
2,928
0.5
25
105
54
10
1
1
480
2,100
14
160
1,686
17
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Table 5. (continued).
INWMIS waste
category Type of waste
- Cr+3
- Chromates
- Ether
- Ethylene glycol
- Mercury
- Methylene
dithiocyanate
- Misc. chemicals
Morpholine
- Paint
- Paint cans
- Powdered boric acid
Resin
- Soda ash
- Sodium dichromate
sludge
- Sulfuric acid
- Used paint
- Zircalloy turnings
- Zirconium chips
Source
- ANL
- NRF, TRA
- ANL
- ANL
- TAN
- NRF
- NRF
- NRF
- CFA.NRF,
TRA
- CPP
- TAN
- TRA
NRF
- ANL
- TAN
' NRF
- ANL
- TAN
Solid Solid Liquid
volume weight volume
(yd3) (Ib) (gal)
590
268 6,520
1
268 165
4
50
3,141
95
2 52
6
2
38,767
9,100
15
59
449
1
1
18
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trenches; however, some nonfriable asbestos was disposed in Landfill El. According to personnel
interviews, chemical or solvent disposal to Landfill HI was relatively infrequent. Some of the
drums disposed to the landfill did contain material or liquid absorbed on rags or diatomaceous
earth, but the majority of the drums were empty upon disposal. Oil or sludge disposal to
Landfill HI was not noted during the personnel interviews. Table 6 summarizes the wastes
including volume estimates by waste types disposed to CFA Landfill ffl.
5.3 Nature and Extent of Contamination
The following sections discuss the results of the site characterization conducted at each
landfill to identify contaminants present in site soil, vadose zone, groundwater, and air.
5.3.1 Surface Soil
Surface soil samples were collected from the soil covers of each landfill for volatile organic,
semivolatile organic, and inorganic compound analyses. Gross alpha/beta and gamma-emitting
radionuclides were also analyzed for soil samples collected at CFA Landfill I. No volatile organic
compounds were found in soil samples collected at Landfills I and HI. A few volatile organic
compounds were detected in soil collected from some locations at Landfill n, but all
concentrations detected in soil collected from this landfill are all well below the risk-based
screening levels. Semivolatile organic compounds, including benzo(a$anthracene, benzo(a)pyrene,
chrysene, dibenzo(a,h)anthracene, and indeno(l,2,3-cd)pyrene were detected in soil collected from
Landfill I at concentrations ranging from 0.04 to 0.89 mg/kg and at Landfill n at concentrations
ranging from 0.044 to 0.92 mg/kg. These compounds are commonly referred to as polycyclic
aromatic hydrocarbons (FAHs); compounds found in asphalt or petroleum distillates, common
wastes disposed in the landfills. Inorganic data from the landfills' cover soils were compared to
naturally occurring background concentrations for INEL soils. Inorganics above naturally
occurring background levels at Landfill I include beryllium, chromium, lead, silver, and zinc. The
inorganics chromium, lead, silver, and zinc were detected at concentrations well below the risk-
based screening levels. Inorganic analyte concentrations detected at Landfills n and HI were
within the common range expected for soils of this area. Cobalt-60 was the only radionuclide
detected at Landfill I at one sample location above background concentrations.
In summary, contaminants of concern identified for CFA Landfill I include beryllium,
cobalt-60, and benzo(a)pyrene; a few PAHs at concentrations of less than 1 mg/kg at Landfill II;
and no contaminants of concern were identified in the surface soils from the cover of Landfill ID.
5.3.2 Subsurface Soil Sampling of Landfill II
Seven boreholes were drilled into the waste to the top of the underlying basalt layer at
Landfill n to (a) determine the nature and concentration of leachable contaminants within and
below the waste unit, and (b) determine if leachate is present in or below the landfill. Soil
samples were collected within and below the waste unit for volatile organic, semivolatile organic,
and inorganic compound analyses. The drilling investigation indicated the presence of PAHs
(compounds present in asphalt or petroleum products) at concentrations ranging from 0.15 to
0.75 mg/kg within the waste unit of Landfill n and correlates with the waste inventory evaluation.
This suggests that the major types of waste that are present in quantities that appear to pose
19
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Table 6. Estimated waste volumes for CFA Landfill HI. (The INWMIS volume estimates for
Landfill HI have been adjusted to reflect that waste was also disposed to the rubble landfill from
1982 to 1984.)
Solid Liquid
weight volume
Type of waste Source (yd3) (Ib) (gal)
INWMIS waste
category
Solid
volume
(yd3)
1. Trash and
sweepings
2. Cafeteria
garbage
3. Wood and
scrap lumber
4. Masonry,
concrete
- Office trash, paper,
cardboard, plastic,
glass, etc.
- Used grease
- Soybean oil
- Vegetable oil
- Food waste
- Up to 70% moisture
Wood and scrap
lumber
- Scrap lumber
- Used masonry
- Used concrete
5. Scrap metal - Scrap metal
6. Weeds, grass,
trees
7. Dirt, gravel
Scrap metal from
welding, pipe fitting
Sheet metal
operations
Metal vehicle parts
including wheels,
mufflers, bearings,
vehicle batteries, etc.
Weeds, grass, and
trees from landscape
maintenance
operations
Din and gravel from
maintenance,
construction, and
demolition projects
ANL, ARA, CFA,
CPP, NRF, PBF,
RWMC, TAN, TRA
WRTF
ANL, CFA, CPP,
NRF, TAN, TRA
ANL, ARA, CFA,
CPP, LOFT, NRF,
PBF, RWMC, TAN,
TRA, WRTF
ANL, CFA, CPP,
NRF, PBF, RWMC,
TAN, TRA, WRTF
ANL, ARA, CFA,
CPP, NRF, PBF,
RWMC, TAN, TRA,
WRTF
ARA, CFA, CPP,
NRF, RWMC, TRA
CFA CPP, NRF, PBF,
RWMC, TRA, WRTF
44,984
9339
125
3,947
2211
809
217
20
-------
Table 6. (continued).
INWMIS waste
category
8. Asphalt
9. Asbestos
10. Other - must
specify
96. Oil
98. Chemicals
Type of waste
- Waste asphalt from
maintenance,
construction, and
demolition projects
- Asbestos
Asbestos coated
materials such as
pipes, etc.
Asphalt and gravel
- Barrels
- Bucket boxes
- Dirt and grass
- Din and rock
- Misc.
- Outdated drugs
Resin barrels
- Roofing materials,
plastic barrels
Sod, weeds, and
gravel
- Weeds, gravel
- Asphalt
- Outdated
medications
- Paint in cans
- Paints
Source
- ANL,CFA,CPP,
NRF, PBF, TAN,
TRA
- ANL,CFA,CPP,
NRF
- CFA
- CPP
- CPP
- CFA
- PBF
- CPP
- CFA
- TRA
- CFA
- CPP
- CPP
- RWMC
- CFA
- NRF
- CFA
Solid
volume
(yd3)
0
88
1,697
40
1
129
150
5
1
14
5
11
4
Solid Liquid
weight volume
(Ib) (gal)
100
6
25
30
21
-------
potential contaminant sources include asphalt, oil, and oil sludge. Due to the heterogeneous
nature of the waste and the limited number of boreholes, complete characterization of the
landfills was not expected.
5.3.3 Vadose Zone Soil Gas
A shallow soil gas survey of Landfills I, n, and HI was performed by collecting soil gas
samples at a depth of approximately 4 ft. Soil gas samples were also collected from nine
boreholes instrumented with gas ports at Landfills II and HI. The gas ports ranged in depth from
12 to 31 ft The soil gas samples were analyzed for volatile organic compounds and methane.
Several volatile organic compounds were detected in gas samples collected from all three landfills
at relatively low concentrations.
Methane, a common landfill gas, was not detected at Landfill I but was found at
concentrations ranging from 14 to 120,000 parts per million (ppm) at Landfill n and 14 to
1,600 ppm at Landfill JJJ in soil gas samples collected from 4 ft below the landfill surface.
Methane was detected in only three of the nine boreholes sampled, and these concentrations
were all below the TJEL for methane of 53,000 ppm. Methane concentrations in the boreholes
have decreased from previous sampling of these boreholes in 1988 and 1989. The presence of
methane is indicative of the biological decomposition of the organic material (i.e., cafeteria waste)
that was disposed to the landfills, and the concentrations detected are in compliance with EPA
solid waste disposal facility criteria, where (a) the concentration of methane gas generated by the
landfill does not exceed 25% of the LEL for methane in facility structures, and (b) the
concentration of methane gas does not exceed the LEL for methane at the facility property
boundary.
5.3.4 Leachate Migration
Analysis of salinity probe data collected from January 1988 to January 1991 at Landfills n
and III was also conducted. During December 1987, a shallow drilling program was implemented
at CFA Landfills n and HI. The objectives of the program included monitoring hydraulic
behavior of the landfill soil to quantify the amounts and rates of water movement into and
through the soil profile. Nine boreholes (four at Landfill n and five at Landfill HI) were drilled
and instrumented with a total of 16 salinity probes. Salinity probes are used to measure the
electrical conductance of soil water. Conductance is proportional to the dissolved solids or salts
in the water. Leachate (water that has contacted the waste) from landfills is expected to be much
higher in dissolved solids than natural soils. Therefore, the salinity probes were used to monitor
for migration of leachate from the landfill. Data from these probes were collected on roughly a
monthly basis from January 1988 to January 1991.
An evaluation of the salinity probe data indicated that the probes underwent a period of
equilibration with the soil lasting until late summer of 1988. Data from salinity sensors in two
boreholes at CFA Landfill JJJ indicate that leachate migration may have occurred at these
locations. Unfortunately, neither-soil moisture content nor soil matric potential (also monitored
at the landfills as part of this program) was measured in the vicinity of these boreholes. The
additional data could have provided supporting evidence for leachate migration in the form of soil
moisture levels and drainage amounts. Thirteen salinity sensors at the other seven borehole
22
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locations provided little or no indication of leachate migration. Readings were within the range
of values typical for saline desert soils. It was concluded that none of the probes at Landfill n
indicated migration of leachates with high dissolved solids, and three of the probes (two at the
same borehole) at Landfill HI indicated potential migration of leachates with high dissolved solids.
Soil moisture and potential leachate migration appears to be a spatially variable, localized
phenomenon at the landfills.
A program was initiated under the RI to drill seven boreholes into Landfill n through the
waste unit to the underlying basalt to determine if leachate is present in or below the landfill. A
saturated leachate-bearing layer or perched water body was not encountered during the drilling
and sampling of these boreholes, or during the previous (1987) RCRA drilling investigation at
Landfills II and ffl. There is no record of a saturated leachate-bearing layer or perched water
body being encountered during any drilling investigation conducted at these landfills at any time.
Weekly toe slope investigations of CFA Landfill n were initiated in June of 1993 and
continued through September 1993, and then intermittently through October, November, and
December. The investigation involved walking the slope of the landfill to check for moisture and
free liquids. At no time was the visible presence of leachate observed anywhere on the landfill or
the toe slope of the landfill.
5.3.5 Groundwater
Three rounds of groundwater samples were collected and analyzed from a network of 9 to 10
monitoring wells located both upgradient and downgradient from the CFA landfills and from two
production wells used for drinking water at CFA. The samples were analyzed for volatile organic
compounds, inorganic compounds, nitrate, sulfate, chloride, fluoride, and alkalinity.
All volatile organic compounds detected during the three phases of sampling are well below
maximum contaminant levels (MCLs). No specific source of volatile organic compounds can be
identified because concentrations are generally low (near or below instrument detection limits) or
detected in both upgradient and downgradient wells. Slight differences in upgradient and
downgradient concentrations noted include low concentrations (<1 ftg/L) of trichloroethylene
detected in downgradient wells only and chloroform detected in downgradient wells only, but
attributed to sample contamination.
Most inorganic compounds detected in the groundwater were below the inorganics' MCL,
with the exception of beryllium, cadmium, and lead. Beryllium was detected above the MCL of
4 ug/L in groundwater collected from three downgradient wells during Phase I sampling at
concentrations ranging from 5.8 to 93 Mg/L. However, duplicate samples collected from two of
these downgradient wells at the same time were nondetects for beryllium. Beryllium was not
detected in groundwater collected from any of the wells during the Phase n sampling. Beryllium
was again detected in groundwater collected from one downgradient well during the Phase IH
sampling at a concentration of 4.6 /ig/L. However, a duplicate sample collected from this same
well at the same time was also a nondetect for beryllium. The inconsistency in the data suggest
that the beryllium results are possibly false positives or potential anomalies. Some possible
explanations for the inconsistent beryllium data include problems with sample collection,
preservation, and laboratory analysis, or possible seasonal (spring) influence on groundwater
23
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quality. Since the samples are unfiltered, the positive beryllium results may be representative of
the original metallic ion content of the silt or clay particles present in the formation and any
sorption of ions to the particles from friction-related wear of the pump rather than introduced
from a potential waste source, such as the landfills.
Cadmium was detected above the MCL of 5 ug/L in groundwater collected from upgradient
wells at concentrations ranging from 8 to 106 figfL and downgradient wells at concentrations
ranging from 5.3 to 17 jig/L during all three phases of sampling. The distribution of cadmium in
both upgradient and downgradient wells, coupled with the fact that concentrations of cadmium
are not significantly higher in the downgradient wells, suggests that the landfills may not be the
source of cadmium in the groundwater. Background concentrations of cadmium in water from the
SRPA generally are less than 1 ng/L. Given the uncertainty of the cadmium and beryllium data,
these contaminants were identified as potential contaminants of concern and were quantitatively
assessed in the human health risk assessment.
Lead was detected above the action level of 15 ug/L in groundwater collected from
upgradient well LF 3-11 at a concentration of 56.7 ug/L during the Phase II sampling. Detections
of lead in downgradient wells were below the action level. Prior to 1984, approximately 340 Ib of
lead was disposed to wastewater discharged at ICPP, a facility upgradient of the landfills. The
wastewater was discharged to the ICPP injection/disposal well. (The source of this information on
lead disposal, as cited in the Remedial Investigation report, is "Orr, B. R. and L. D. Cecil, 1991,
Hydrologic Conditions and Distribution of Selected Chemical Constituents in Water, Snake River
Plain Aquifer, INEL, Idaho 1986 to 1988, U.S. Geological Survey Water-Resources Investigations
Report 91-4047, DOE/ED-22096, p. 44.") Because lead was detected in upgradient wells and not
significantly higher in downgradient wells, and a known upgradient source exists, its presence in
the groundwater is considered to be unrelated to the CFA landfills.
Nickel was detected above the risk-based screening concentration of 70 pgfL in upgradient
well LF2-11 at a concentration of 99 /ig/L during Phase n sampling and in downgradient well
LF2-12 at a concentration of 117 ug/L during Phase III sampling. However, the filtered sample
collected from this downgradient well was a nondctect for nickel, and it was not detected in
groundwater collected from this well during the Phase I and n sampling. The inconsistency in the
data suggests that the nickel result is possibly a false positive or potential anomaly. For example,
paniculate nickel may have been introduced into the water pumped from this well due to friction-
related wear inside the pump.
Zinc was detected in one upgradient well and one downgradient well at concentrations of
35,500 and 1,380 p.gfL, respectively, during Phase II sampling, and in one upgradient and one
downgradient well at concentrations of 1,050 and 2370 ug/L, respectively, during the Phase III
sampling. These concentrations are above the risk-based screening concentration of 1,000
The chloride, fluoride, nitrate, and sulfate concentrations during Phase I, n, and ni sampling
events were all below their respective primary or secondary MCLs and within the range of
background concentrations common to the SRPA under the INEL.
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5.3.6 Air
Volatile organic compound emission-rate measurements were taken from the surface of all
three landfills using a surface flux chamber and sorbent cartridges. Emissions are very low (0.0089
to 1.6 fig/m2/min) and similar in terms of type and level of emissions for the locations tested on all
three landfills. Methane was not detected in air emanating from the surface of these landfills.
Volatile organic compounds measured at Landfill I include acetone, benzene, methylene chloride,
1,1-dichloroethene, 1,1,1-trichloroethane, toluene, tetrachloroethene, and trichloroethene.
Volatile organic compounds measured at Landfill n include acetone and dichlorodifluoromethane.
Volatile organic compounds measured at Landfill HI include acetone, dichlorodifluoromethane,
and toluene. The emissions from the landfills are well below risk-based screening levels and do
not pose a health hazard to the public or workers.
6. SUMMARY OF SITE RISKS
The human health risk assessment for the CFA landfills evaluated potential adverse health
effects associated with exposure to contaminants of concern detected at the landfills under the
no-action alternative for both present workers and potential future residents. The risk assessment
was conducted in accordance with EPA Risk Assessment Guidance for Superfund, Volume I:
Human Health Evaluation Manual and Volume II: Environmental Assessment Manual and other
EPA guidance. The risk assessment methods and results are summarized in the following
sections. More detailed information may be found in the "Remedial Investigation/Feasibility Study
for Operable Unit 4-12: Central Facilities Area Landfills I, n, and HI at the Idaho National
Engineering Laboratory."
6.1 Human Health Risks
The human health risk assessment consisted of identifying contaminants of potential concern,
an exposure assessment, a toxicity assessment, risk characterization, and an uncertainty analysis.
Contaminants of concern were identified based on field investigations, which were conducted to
characterize surface soil, groundwater, and air emissions for the landfills, and waste inventory
records. The exposure assessment detailed the exposure pathways that exist at the site for current
workers and potential future residents. The toxicity assessment documented the adverse health
effects to an individual as a result of exposure to a site contaminant The human health risk
assessment evaluated both noncarcinogenic health effects and carcinogenic risks associated with
exposure to site contaminants. Although this risk assessment was performed, uncertainties (see
Section 6.1.4) in the source term and the inability to fully characterize the landfills were the
primary factors in considering remedial action to be taken at these landfills.
6.1.1 Identification of Contaminants of Concern
Chemical contaminant data from field investigations conducted for the CFA landfills surface
soil, groundwater, and air emissions were evaluated to determine the most significant site-related
contaminants of potential concern for use in the quantitative risk assessment. Contaminants of
concern identified in the surface soil from the cover of Landfill I include beryllium,
benzo(a)pyrene, and cobalt-60. Contaminants of concern identified in the surface soil from
25
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Landfill II include the PAHs benzo(a)anthracene, benzo(a)pyrene, chrysene,
dibenzo(a,h)antbracene, and indeno(l,2,3-cd)pyrene. No contaminants of concern were identified
in the surface soil from the cover of Landfill ffl.
Three rounds of groundwater samples were collected from the landfill monitoring wells and
two production wells used as a drinking water source at CFA. Beryllium, cadmium, and zinc were
identified as contaminants of concern for the groundwater pathway. Future groundwater
concerns, as a result of potential future leaching of the source term to the groundwater, were
addressed through modeling and indicated no unacceptable groundwater health risk to potential
future residents. Therefore, no additional contaminants of concern were included with the
groundwater pathway. However, uncertainties exist in the modeling due to limited field data and
incomplete source term inventory information.
Volatile organic compound emission rate measurements were taken at the surface of all
three landfills. The emissions from CFA Landfills I, n, and HI are very low and do not pose a
health threat to the public or workers. No contaminants of concern were identified for the air
pathway.
6.1.2 Exposure Assessment
The objective of the exposure assessment was to estimate the type and magnitude of
exposures to the contaminants of concern identified for the media associated with the CFA
landfills. The exposure assessment identified potentially exposed populations and exposure
pathways, estimates of exposure concentrations, and estimates of contaminant intakes for
exposure pathways.
6.1.2.1 Potentially Exposed Populations. The potentially exposed populations identified
include current site workers and potential future residents that may inhabit the site when DOE
relinquishes control of the site (approximately 30- and 100-year scenarios).
6.1.2.2 Exposure Pathways. An exposure pathway describes the course a contaminant
takes from the source to the exposed individual. The current land use scenario evaluated the
exposure of workers to the incidental ingestion of soil from the cover of CFA Landfills I and n,
external exposure to cover soil at CFA Landfill I, and ingestion of groundwater pumped from the
CFA production wells. The future land use scenario evaluated the exposure of potential future
residents to the incidental ingestion of soil from the cover of CFA Landfills I and n, external
gamma radiation exposure to cover soil at CFA Landfill I, and ingestion of groundwater pumped
from the downgradient monitoring wells and the CFA production wells. Exposure to inhalation
of dust was not evaluated because it is not considered a viable pathway due to the depth of the
contaminants.
6.1.2.3 Exposure Concentrations. The validated analytical results of soil collected from
the cover of CFA Landfill I and II were used to estimate the reasonable maximum exposure
(RME), which is the greatest exposure that could reasonably be expected to occur at the site.
The RME concentration was determined by the 95% upper confidence limit (UCL) on the
arithmetic mean of the measured contaminant concentrations from the CFA Landfill I and II
cover soil. Exposure concentrations in groundwater for the current industrial scenario were based
on the three phases of 1993 validated water quality data for the CFA production wells, whereas
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exposure concentrations in groundwater for future residents were based on the three phases of
1993 validated water quality data for the downgradient monitoring wells and the CFA production
wells. The RME concentration for workers was determined by the 95% UCL on the arithmetic
mean of the measured contaminant concentrations for the CFA production wells. The RME
concentration for future residents was determined by the 95% UCL on the arithmetic mean of
the measured contaminant concentrations for the downgradient monitoring wells and CFA
production wells. The RME factors used in the risk assessment can be found in Table 6-16 of the
Remedial Investigation report
6.1.3 Risk Characterization
The objective of the risk characterization, the final step in the overall risk assessment
process, is to integrate the results of the exposure assessment and the toxicity assessment to
estimate risk to humans from exposure to site contaminants. The toxicity and exposure
assessments are summarized and integrated into quantitative expressions of risk. The carcinogenic
effects or probability that an individual will develop cancer over a lifetime of exposure are
estimated from projected intakes and chemical-specific dose-response relationships. Noncarcino-
genic effects are characterized by comparing projected intakes of substances to toxicity values.
The calculation of health risks from the potential exposure to carcinogenic contaminants
involves multiplying the pathway-specific slope factor (SF) for each carcinogen by the estimated
chronic intake value. The risk is expressed probabilistically and is compared to the acceptable
NCP risk range of 1 in 10,000 to 1 in 1,000,000 (i.e., 1 x 10"4 to 1 x 10"6). An excess lifetime
cancer risk of 1 in 10,000 indicates that an individual has one excess chance in ten thousand of
developing cancer over a lifetime of exposure to a site-related contaminant
The chronic reference dose (RfD) is used to compare toxic effects of noncarcinogenic
contaminants. The hazard potential from toxic effects is computed as the ratio of estimated
chronic intake to the pathway-specific RfD, and is referred to as the hazard quotient. Hazard
quotients less than 1.0 indicate that intake is less than the RfD. The sum of the hazard quotients
is equal to the hazard index The hazard quotient or index should be interpreted as an index of
relative health hazard and does not provide a probabilistic expression of risk. A value less than or
equal to 1.0 indicates that it is unlikely for even sensitive subpopulations to experience adverse
health effects. A value greater than one requires further considerations and risk management
decisions.
6.7.3.7 Current Industrial Use. Health risks were calculated for a current industrial
scenario where the workers incidentally ingest soil from the cover of CFA Landfills I and n,
external gamma radiation exposure to soil at CFA Landfill I, and ingest water from the CFA
production wells. As shown in Table 7, the potential risk for incidental ingestion of soil
contaminated with benzo(a)pyrene and beryllium is 3 x 10*7 and 1 x 10"6, respectively. The
external gamma radiation exposure of cobalt-60 contaminated soil at CFA Landfill I is 5 x 10"6.
The ingestion of groundwater contaminated with beryllium is 7 x 10'5. All potential risks are
within or below the accepted risk range of 1 x 10"4 to 1 x 10"6. As shown in Table 7, the hazard
quotient for toxic effects from ingesting groundwater contaminated with cadmium and zinc is
0.1 and 0.0008, respectively. These values and the total hazard index are much less than 1.0,
indicating that it is unlikely that workers will experience adverse health effects.
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Table 7. Summary of potential carcinogenic risks and noncarcinogenic hazard quotients for CFA
Landfills I, II, and El.
Exposure pathway
Contaminant of
concern
Current
worker risk
Future resident
riskb
Landfill I
External exposure
Soil ingestion
Groundwater ingestion
Landfill n
Soil ingestion
Groundwater ingestion
T-andfm HI
Groundwater ingestion
Cobalt-60
Beryllium
Benzo(a)pyrene
Cadmium
Zinc
Benzo(a)pyrene
Beryllium
Cadmium
Zinc
Cadmium
Zinc
5 x ID"6
1 xlO"6
4 x ID"7
O.la
0.0008*
3 x lO'7
7 x lO"5
O.la
0.00088
O.la
0.0008°
5 x 10'11
1 x 10'5
4X10-6
0.4a
0.048
7 x 10'7 (adult)
2 x 10-6 (child)
2X10-4
0.4a
0.04°
0.4a
0.04a
a. Estimates of noncarcinogenic risks, in the form of hazard quotients, are all less than 1,
indicating that it is unlikely even for sensitive subpopulations to experience adverse health
effects.
b. The future resident (both 30- and 100-year) RME concentrations were determined by the
95% UCL on the arithmetic mean of the measured contaminant concentrations from the
landfill cover soil and the downgradient wells and the CFA production wells.
Note: Even though the risk assessment indicates that the landfills do not currently present an
unacceptable risk to human health, a remedial action of containment is warranted at the site
due to the uncertainty associated with the waste regarding the types and amounts of potentially
hazardous waste disposed.
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6.7.3.2 Future Residential Use. Health risks were calculated for a future residential
scenario (both 30- and 100-year) where the residents incidentally ingest soil from the cover of
CFA Landfills I and n, external gamma radiation exposure to soil at CFA Landfill I, and ingest
groundwater pumped from downgradient monitoring wells and CFA production wells. As shown
in Table 7, the potential risk for incidental ingestion of soil contaminated with benzo(a)pyrene
and beryllium is 2 x 10"6 and 1 x 10"5, respectively. The external gamma radiation exposure risk
of cobalt-60 contaminated soil at CFA Landfill I is 5 x 10*11. The potential risk for ingestion of
groundwater contaminated with beryllium is 2 x 10"4. All potential future risks are within or
below the accepted risk range of 1 x 10~* to 1 x 10"6 with the exception of the potential future
risk of 2 x 10^ for the ingestion of groundwater contaminated with beryllium. It is important to
note that this potential future risk is based on beryllium groundwater results that are considered
false positives or potential anomalies and therefore is not considered a driver for action (see note
in Table 7). As shown in Table 7, the hazard quotient for toxic effects from ingesting
groundwater contaminated with cadmium and zinc is 0.4 and 0.04, respectively. These values and
the total hazard index are much less than 1.0, indicating that it is unlikely residents will experience
adverse health effects.
6.1.4 Uncertainty
In this risk assessment, methodologies are employed to evaluate the risks to human health
from contaminants of concern detected in the groundwater and the soil cover of CFA Landfills I
and n. It should be recognized that such risk assessment methodologies represent an inexact
science, and their application is associated with uncertainties. Uncertainties arise because of the
need to make assumptions and inferences to compensate for the unknowns or lack of data.
Table 8 summarizes the major uncertainties in this risk assessment
Although there are considerable sources of uncertainty in the risk assessment methodology,
the consistent adoption of conservative assumptions and parameter values, and adherence to EPA
guideline recommendations are considered to have provided reasonable estimates of risk that are
currently posed by the site. However, due to the heterogeneous nature of the waste, complete
characterization of the landfill contents was and is not expected. Therefore, future use of the
landfills that may involve excavation of the landfill subsurface materials could increase risks of
exposure to contaminants (via inhalation, ingestion, and dermal contact) for potential future
construction workers and residents. Furthermore, uncertainty in the source term (i.e., waste
inventory) used in the groundwater modeling contributes to uncertainty in the potential future
groundwater health risk.
6.2 Environmental Risk Assessment
This environmental risk assessment is a qualitative appraisal of the potential effects of the
CFA landfills on plants and animals other than people and domesticated species. A quantitative
environmental assessment is scheduled to be performed as part of the INEL-wide comprehensive
RI/FS tentatively scheduled for 1998 and may also be performed as part of the overall WAG 4
comprehensive RI/FS. This assessment is a cursory look at the potential impacts to ecological
receptors from present conditions at the CFA landfills. The assessment identifies sensitive
nonhuman and nondomesticated species and characterizes potential exposure pathways, including
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Table 8. Summary of major uncertainty factors associated with the CFA Landfills baseline risk
assessment
Effect on risk assessment8
Potential magni- Potential magni- Potential magnitude
tude for over- tude for under- for over or under-
Uncertainty factor estimating risk estimating risk estimating risk
Environmental sampling and analysis
Sufficient samples may not have Med
been taken to fully characterize the
landfills
Systematic or random errors in the Low
chemical analyses
Representativeness of samples Low
Field sampling errors Low
Heterogeneity of sample matrix Low
Estimating exposure parameter
Use of EPA RME values Low
Exposure of INEL workers Med
Exposure of future residents Med
Toodtity Assessment
Use of EPA values Low
Lack of SFs for some contaminants Low
a. Uncertainty factors marked low may affect estimates of risk by less than one order of magnitude;
assumptions marked moderate may affect estimates of risk between one and two orders of magnitude;
and assumptions marked high may affect estimates of risk by more than two orders of magnitude. The
qualitative ratings are based on best professional judgement and do not represent an actual quantitative
analysis of uncertainty.
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dermal contact with contaminated soil, inhalation of soil dust, and the ingestion of contaminated
plants or animals in the study area. The data for this environmental assessment were developed
from a review of existing literature. No site-specific field sampling or receptor study was
performed for this assessment
6.2.1 Contaminants of Concern
Contaminants of concern detected in cover soils at CFA Landfills I and n include PAHs
such as benzo(a)anthracene, benzo(a)pyrene, chrysene, dibenzo(a,h)anthracene, and
indeno(l,23-cd)pyrene. These contaminants will be discussed from an ecological perspective.
6.2.2 Exposure Assessment
The three principal direct routes of exposure for terrestrial and avian species are ingestion,
inhalation, and dermal contact The major route of exposure to PAHs for ecological receptors at
the landfills is likely dermal contact with subsurface contaminated soil. This exposure would be
limited to burrowing animals such as Townsend's ground squirrel, deer mouse, and kangaroo rat.
Subsequently, the species that use these burrowing animals as a food source, such as coyotes or
birds of prey, would also be at risk from ingestion of contaminated food sources. Transport of
pronghorn antelope or sage grouse is also possible; however, use of the area by game species is
probably minimal due to poor vegetation cover and proximity to areas of human activity.
Moreover, the small proportion of landfill acreage in comparison to typical game species total
ranges and by the taking of prey outside the area of influence of the landfills would preclude
significant bioconcentration in game species. Inhalation of contaminated fine soil particles, also
by burrowing animals, may also be important Another possible exposure route is ingestion of
contaminated soil
6.2.3 Risk Characterization
PAHs, compounds found in asphalt and petroleum distillates, are byproducts of the burning
of organic material, and as such, are common in the environment PAHs identified as
contaminants of concern in this study are carcinogens, with a weight-of-evidence class of B2,
probable human carcinogen with sufficient evidence of carcinogenicity in animals with inadequate
or no evidence in humans. Benzo(a)anthraccnc produced tumors in mice at the site of
application, and chrysene produced malignant tumors of the liver, lung, lymphatic system, and skin
in mice. Since most PAHs are carcinogenic to varying extent, they may present a risk of cancers
to burrowing animals who come in contact with or ingest the PAHs.
6.2.4 Conclusions and Limitations
This environmental risk assessment provides a broad overview of possible exposure of the
ecosystem to the potential contaminants of concern. The contaminants (PAHs) are limited in
distribution; thus, any effect that could be identified would likely be in an individual organism and
not a population or community. Moreover, PAHs are typically immobile in soils and are less
likely to be transferred through the food chain. These factors, combined with the lack of water,
vegetation, and habitat value for wildlife in the area of the CFA landfills, are likely to limit
uptake and accumulation of contaminants in the food chain. There are no known endangered or
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threatened species residing year-round at the INEL (although they may be found visiting the
area), and no known critical habitats. In summary, the contaminants in the CFA landfills are not
considered to have any significant disruptive effects on animal or plant populations or the local
ecosystem.
Limitations to this qualitative ecological assessment include lack of site-specific information
on the exposure frequency, duration, and routes of exposure for terrestrial species to potential
contaminants of concern. Also, without adequate tenacity data, the ecological risk of PAHs in the
CFA landfills cannot be quantitatively determined.
7. DESCRIPTION OF ALTERNATIVES
The remedial investigation of OU 4-12 indicated that the overall risk associated with the
landfills is within the generally acceptable limits of CERCLA; however, due to the uncertainty
associated with the landfill contents with regard to the types and amounts of potentially hazardous
waste disposed and the need for containment of the landfill contents, a remedial action of
containment is warranted for the site. Remedial action of containment is consistent with EPA's
presumptive remedy guidance for CERCLA municipal landfills. As such, remedial action
alternatives were developed and analyzed in detail for the CFA landfills. Prior to developing
alternatives, remedial action objectives (RAOs) were established. These objectives and
descriptions of developed alternatives are included in the following sections.
7.1 Remedial Action Objectives
The intent of the RAOs is to set goals for protection of human health and the environment
that are consistent with EPA's presumptive remedy guidance. The goals for the CFA landfills are
designed specifically to lessen the potential threat (Le., maintain risk factors within acceptable
limits) to human health and the environment posed by direct contact with and migration of
contaminants disposed at the CFA landfills. The attainability of RAOs is addressed through the
detailed evaluation of overall protectiveness afforded by each remedial action alternative.
In order to identify appropriate RAOs, risks associated with the landfills had to be evaluated.
As indicated by the risk assessment presented in Section 6, the present risk associated with the
CFA landfills is within the generally acceptable limits of CERCLA (Le., the landfills do not pose a
significant threat to human health and the environment), and the risk as quantified does not
warrant an action at the CFA landfills. However, as is typical for landfills, there is a level of
uncertainty in characterizing potential future risk, particularly related to the potential for
contaminant migration via leachate generation and cover erosion. As such, the RAOs derived for
the landfills focus on reducing concerns about potential risk that could not clearly be evaluated as
part of the investigation of the landfills. The RAOs include:
Prevent direct contact with the landfill contents.
Minimize the potential for erosion and infiltration at the surface.
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Ensure that drinking water standards are not exceeded in the SRPA due to the migration
of contaminants from the landfills.
These RAOs were developed to prevent future unacceptable risk from exposure to landfill
contaminants, rather than to address any existing unacceptable risk. Adherence to these RAOs is
consistent with a presumptive remedy approach that is typical for CERCLA municipal landfills.
7.2 Summary of Alternatives
In accordance with Section 121 of CERCLA, the Feasibility Study (FS) identified and
evaluated alternatives in terms of achieving the stated RAOs. The alternatives evaluated in the
FS for the CFA landfills were:
Alternative 1 - No Action with Monitoring.
Alternative 2 - Institutional Controls with Monitoring.
Alternative 3 Uniform Containment with Native Soil Cover, Institutional Controls, and
Monitoring.
Alternative 4 - Containment with Single-Barrier Cover, Institutional Controls, and
Monitoring.
The remedial action alternatives were developed by combining process options evaluated in
the FS in a manner that focused alternatives on institutional controls and components of a
CERCLA municipal landfill presumptive remedy. The No Action alternative was developed to
provide a baseline against which other alternatives could be compared.
Substantive Federal and state action-specific applicable or relevant and appropriate
requirements (ARARs) have been identified for the alternatives. These ARARs and significant
to-be-considered (TBC) criteria are listed in Table 9. The primary ARAR relates to landfill
closure under RCRA, as implemented by the State of Idaho under the Idaho Hazardous Waste
Management Act (hereinafter, this Idaho statute will be referred to as RCRA). These RCRA
requirements were determined to be relevant and appropriate, rather than applicable, because
there is no conclusive evidence that RCRA-hazardous waste was disposed to the landfills after the
promulgation of the RCRA Subtitle C requirements for hazardous waste. Consideration of the
RCRA requirements as relevant and appropriate allows for a combination of requirements for
landfill closure. The agencies have determined that, based on characteristics of the CFA landfills
and potential remedial action alternatives, "hybrid" landfill closure procedures in CERCLA are
suitable.
The substantive RCRA requirements identified as ARARs focus on cover design and include
the following primary objectives:
Provide long-term minimization of migration of liquids.
Function with minimum maintenance.
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Table 9. Summary of ARARs and TBC criteria for CFA landfill alternatives.
Statute
Idaho Hazar-
dous Waste
Management
Act, 1983 and
as amended
Idaho Environ-
mental Protec-
tion and Health
Act, 1972 and
as amended
Regulation or Title
Standards for Owners
and Operators of
Hazardous Waste
Treatment, Storage,
and Disposal Facilities,
IDAPA § 16.01.05.008
"Landfills, Closure and
Post-Closure Care*
(derived from 40 CFR
264.310)
Rules for the Control
of Fugitive Dust and
General Rules, IDAPA
Sections 16.01.01.650
and .01.651
Alternative 3 Alternative 4
Alternative 2 Containment Containment
Alternative 1 Institutional with Native with Single
No Action Controls Soil Cover Barrier Cover
R/No R/No R/Yes R/Yes
NotARAR NotARAR A/Yes A/Yes
Presumptive Remedy TBC
for CERCLA
Municipal Landfill
Sites, OSWER
Directive 9355.0-49
RCRA ARARs: Focus TBC
on Closure Require-
ments, OSWER
Directive 9234.2-04FS
Evaluating Cover TBC
Systems for Solid and
Hazardous Waste
(Revised), OSWER
Directive 9476.00-1
Yes/No = meets or does not meet ARARs.
A as applicable.
R = relevant and appropriate.
TBC = to be considered.
TBC
TBC
TBC
TBC
TBC
TBC
TBC
TBC
TBC
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Promote drainage and minimize erosion.
Accommodate settling and subsidence.
Provide a hydraulic conductivity less than or equal to any bottom liner system or natural
subsoils present.
In addition, RCRA monitoring requirements deemed by the agencies to be appropriate
during remedial design will be met.
There were no chemical-specific ARARs identified for the considered alternatives.
Regulations have not been promulgated specific to soil cleanup levels for contaminants that may
be present in soils at the CFA landfills. Also, no location-specific ARARs were identified as
there are no known threatened and endangered species, wetlands, rivers, or floodplains located in
the area of potential remedial activities under the considered alternatives. Areas that may be
impacted by the considered alternatives include soil borrow areas. Borrow areas at the INEL
have been evaluated through an environmental assessment, which determined that these areas do
not impact historical and cultural properties, nor do they impact archeological resources.
7.3 Alternative 1 - No Action with Monitoring
Consideration of the No Action alternative is required by the NCP [40 CFR 300.430(e)(6)]
as a baseline against which other alternatives are compared. Under this alternative, no attempt
would be made to contain the contents of the CFA landfills. The only action taken under this
alternative would be groundwater monitoring. The agencies would review this action, including
the need for continued monitoring and the frequency and scope thereof, within 5 years and every
5 years thereafter. A monitoring plan, developed by the agencies, would define the wells that
would be monitored, parameters to be monitored, frequency of monitoring, and reporting
requirements. Access to the site and possible exposure to site surface soils would not be
prevented under this alternative beyond the period during which DOE maintains control of the
landfill area (assumed to be 30 years).
Alternative 1 would not meet the substantive relevant and appropriate requirements of
RCRA, as implemented by the State of Idaho, identified in Table 9. These requirements focus on
cover design and are summarized in Section 7.2. Alternative 1 would not meet the requirement
that the cover promote drainage and minimize erosion as it does not include measures to provide
for even runoff of precipitation. Net present value costs for implementing groundwater
monitoring (30 years assumed) under this alternative are estimated to be $968,000.
7.4 Alternative 2 - Institutional Controls with Monitoring
In addition to groundwater monitoring as described for Alternative 1, this alternative would
consist of infiltration monitoring and institutional controls including fencing, which would be
implemented after DOE's institutional control period (assumed to be 30 years) to prevent access
to the site and future disturbance of the site soils. Potentially, enforcement of institutional
controls may be by a party other than the DOR Alternative 2 takes no steps to minimize the
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potential for contaminant migration. Actual monitoring locations and frequency would be
identified in a monitoring plan that would be developed as pan of the design for this alternative.
The need for continued infiltration monitoring would be reviewed along with the groundwater
monitoring review as described for Alternative 1. For cost estimating purposes, it was assumed
that neutron probe and lysimeter probe analyses would be performed monthly and semiannually,
respectively, at 18 locations within the landfills. Five of the neutron probe boreholes already
exist.
Alternative 2 would not meet the substantive relevant and appropriate requirements of
RCRA, as implemented by the State of Idaho, identified in Table 9. These requirements focus on
cover design and are summarized in Section 7.2. Alternative 2 would not meet the requirement
that the cover promotes drainage and minimizes erosion as it does not include measures to
provide for even runoff of precipitation. Net present value costs for implementing groundwater
and infiltration monitoring (30 years assumed) and installing a fence around the landfills at the
end of DOE's control of the site are estimated to be $1,940,000.
7.5 Alternative 3 - Uniform Containment with Native Soil Cover,
Institutional Controls, and Monitoring
This alternative would ensure a minimum thickness of at least 2 ft of clean, compactable,
native (i.e., found at or near the INEL) soils cover the entire surface area of the CFA landfills.
This cover of native soil would prevent surface exposure to contaminants in the landfill areas.
The cover would also be constructed to prevent migration of contaminants through dust emissions
or runoff erosion and reduce infiltration and the potential for contaminant migration. The soil
layer would be graded to allow efficient rainwater runoff, and natural vegetation would be planted
to stabilize the soil surface and promote evapotranspiration. Existing soil cover material would be
incorporated in the minimum 2-ft final cover thickness. It is expected that up to 55,000 yd3 of
native soil would have to be brought to the landfills from a source at the site in order to
accomplish the appropriate grading and cover thickness. Grading activities would include
measures to fninimize dust generation. The volume of 55,000 yd3 is an estimate based on data
available from the remedial investigation. Also, the thickness of two feet is considered to provide
an appropriate level of protection in conjunction with institutional controls against direct exposure
at this site and is considered a typical native soil cover thickness for CERCLA municipal landfills
(Design and Construction of RCRA/CERCLA Final Covers, EPA/625/4-91/025). This type of
cover would not include an impermeable layer over the landfill contents; therefore, the
accumulation of landfill gas is not likely to be a concern.
Administrative controls such as placing written notification of this remedial action in the
facility land use master plan would also be required to ensure that potential future activities
would not compromise the integrity of the cover. A copy of the notification would be given to
the Bureau of Land Management (BLM) together with a request that a similar notification be
placed in the BLM's property management records for this site. Borders would be delineated
through the posting of signs warning of the landfills' existence and potentially contaminated soils.
Groundwater monitoring as described for Alternative 1 would be implemented under
Alternative 3 after the placement of the native soil cover. Alternative 3 would also include
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measures to monitor infiltration as described for Alternative 2. Routine maintenance of the cover
would continue as needed. The agencies will review this action, including the need for continued
monitoring and the frequency and scope thereof, within 5 years and every 5 years thereafter.
Alternative 3 would meet the substantive relevant and appropriate requirements of RCRA,
as implemented by the State of Idaho, identified in Table 9. These requirements focus on cover
design and are summarized in Section 7.2. This alternative would also meet the requirements for
control of fugitive dust through engineered methods to minimise dust generation. Net present
value costs for implementing all of the elements described above are estimated to be $3,500,000,
which assumes a 30-year groundwater and infiltration monitoring period.
7.6 Alternative 4 - Containment with Single-Barrier Cover,
Institutional Controls, and Monitoring
This alternative involves placing a single-barrier cover over the entire .surface area of each of
the CFA landfills. The cover would be constructed of either 2 ft of impermeable clay or a
geomembrane layer (for purposes of evaluation, it was assumed that a clay layer would be used
with the clay being a mixture of imported bentonite and native local soils). Two feet of clay is
standard for impermeable covers at landfills (Design and Construction of RCRA/CERCLA Final
Covers, EPA/625/4-91/025). The 2-ft thickness is necessary to maintain the clay layer's integrity
over the long term. Prior to placement of the clay layer, the landfill area would be surveyed to
ensure a minimum of 12 in. of compacted native soil bedding layer was in place. Thirty inches of
native soil would be placed on top of the clay and the area revegetated with indigenous species.
This impermeable type of cover would prevent surface exposure to contaminants in the landfill
areas as well as greatly reduce water infiltration through the landfill contents. As with the native
soil cover described for Alternative 3, this cover would prevent migration of contaminants via dust
emissions or runoff erosion. The top native soil layer would be graded to allow efficient rainwater
runoff. Grading activities would include measures to minimize dust generation. The total amount
of bentonite that would be required is approximately 20,000 tons (based on a 10% blend with
native soils), while the total amount of native soil required would be approximately 350,000 tons
(approximately 260,000 yd3).
It is common practice to manufacture a clayey material by blending local soils with imported
bentonite when local clay soils are not available. In general, silt and silty sand soils with few
gravel or cobble-sized particles are used in blending a clay cover. Poorly graded, sandy soils with
abundant oversized particles are generally unsuitable for blending. Granular bentonite is typically
imported by rail or truck from quarries in Wyoming.
Selected local soils can be mixed with approximately 10% granular bentonite and sufficient
water to allow compaction. The specific proportions to be used at the CFA landfills would
require determination by a laboratory testing program after the native soil site is identified.
Blending can be achieved at the site with a pugmill or other specialized mixing equipment The
material would then be placed on a prepared subgrade and compacted with a sheepsfoot
compactor or other equipment capable of providing "kneading" compaction.
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Administrative controls and posting of signs would be included with this alternative as
described for Alternative 3; groundwater monitoring would be implemented as described for
Alternative 1; and infiltration monitoring would be implemented as described for Alternative 2.
Soil vapor monitoring would also be a component of this alternative. Because the cover would
include an impermeable layer over the landfill contents, landfill gas could potentially accumulate
to unsafe levels. Soil vapor monitoring would provide early indication of such an accumulation of
gas. This monitoring could be ceased over time if the landfill gas levels remain low. It was
assumed that soil vapor monitoring would continue for 30 years after cap installation at five
passive vents located at each landfill; however, the need for the soil vapor monitoring would be
reviewed every 5 years. If gas was to accumulate to unsafe levels, then additional vents could be
installed. Routine cover maintenance would continue as necessary. The agencies will review this
action, including the need for continued monitoring and the frequency and scope thereof, within 5
years and every 5 years thereafter.
Alternative 4 would meet the substantive relevant and appropriate requirements of RCRA,
as implemented by the State of Idaho, identified in Table 9. These requirements focus on cover
design and are summarized in Section 12. This alternative would also meet the requirements for
control of fugitive dust through engineered methods to minimize dust generation. Net present
value costs for implementing all of the elements described above are estimated to be $15,200,000,
which assumes 30 years of groundwater, infiltration, and soil vapor monitoring.
8. SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
CERCLA guidance requires that each remedial alternative be compared according to nine
evaluation criteria that have been developed to serve as a basis for conducting the detailed
analyses of alternatives and selecting an appropriate remedial action. The evaluation criteria are
divided into three categories: (1) threshold criteria that relate directly to statutory findings and
must be satisfied by each chosen alternative, (2) primary balancing criteria that include long- and
short-term effectiveness, implementability, reduction of toxicity, mobility, and volume, and cost,
and (3) modifying criteria that measure the acceptability of the alternatives to state agencies and
the community. The following sections summarize the evaluation of the candidate remedial
alternatives according to these criteria.
8.1 Threshold Criteria
The remedial alternatives were evaluated in relation to the threshold criteria: overall
protection of human health and the environment and compliance with ARARs.
8.1.1 Overall Protection of Human Health and the Environment
This criterion addresses whether an alternative provides protection of human health and the
environment and includes an assessment of how risks posed through each exposure pathway are
eliminated, reduced, or controlled through treatment, engineering controls, or institutional
controls. As noted in Section 7.1, the remedial investigation of OU 4-12 indicated that the
current risk associated with the landfills is within the generally acceptable limits of CERCLA;
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however, there is a significant level of uncertainty in characterizing the landfill contents. Thus, an
effort to reduce the potential for future unacceptable risks is the focus of RAOs for the landfills.
Alternatives 3 and 4 achieve the RAOs identified in Section 7.1, thus satisfying the criterion
of overall protection of human health and the environment. The alternatives accomplish this by
eliminating the direct exposure pathways (i.e., contact with landfill waste and/or contaminated
soils) and reducing the potential for contaminant migration via mechanisms such as erosion at the
surface and infiltration. Through institutional controls, Alternative 2 achieves the RAO to
eliminate direct exposure pathways. However, Alternative 2 does not include measures to reduce
the potential for contaminant migration at the surface or to the SRPA. Alternative 1, No Action,
does not achieve the RAOs.
Overall, Alternatives 3 and 4 would significantly reduce the potential for unacceptable risk at
the CFA landfills. As such, the residual risk associated with Alternatives 3 and 4 is believed to be
acceptable (i.e., fall within or below the acceptable risk range of 10~* to 10"6). Under
Alternative 2, there is a potential that unacceptable risk would remain because Alternative 2 takes
no action to minimize contaminant migration; however, Alternative 2 does include measures to
eliminate direct exposure pathways. Alternative 1, No Action, takes no steps to prevent erosion
at the surface and possible subsequent infiltration, nor does it eliminate direct exposure pathways.
Therefore, it does not reduce the potential for future unacceptable risks that may occur. Thus,
Alternative 1 is not considered to be protective of human health and the environment
8.1.2 Compliance with ARARs
CERCLA, as amended by SARA, requires that remedial actions for Superfund sites comply
with identified substantive applicable requirements identified under Federal and state laws.
Remedial actions must also comply with the substantive requirements of laws and regulations that
are not directly applicable but are relevant and appropriate, in other words, requirements that
pertain to situations sufficiently similar to those encountered at a Superfund site so that their use
is well suited to the site. Combined, these are referred to as applicable or relevant and
appropriate requirements or ARARs. State ARARs are limited to those requirements that are
(1) promulgated, (2) uniformly applied, and (3) are more stringent than Federal requirements.
Compliance with ARARs requires evaluation of the remedial alternatives for compliance with
chemical-, action-, and location-specific requirements.
Alternatives 3 and 4 meet all of the substantive relevant and appropriate requirements of
RCRA identified in Table 9. The requirements considered relevant and appropriate are action-
specific focusing on cover design and include the following primary objectives:
Provide long-term minimization of migration of liquids.
Function with minimum maintenance.
Promote drainage and minimize erosion.
Accommodate settling and subsidence.
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Provide a hydraulic conductivity less than or equal to any bottom liner system or natural
subsoils present
Alternatives 1 and 2 do not meet the substantive relevant and appropriate requirements identified
under RCRA as neither of these alternatives provide a cover designed to promote drainage and
e infiltration. Alternatives 3 and 4 would meet applicable fugitive dust requirements
through engineered controls.
8.2 Balancing Criteria
The balancing criteria are used in refining the selection of the candidate alternatives for the
site. The five balancing criteria are (1) long-term effectiveness and permanence, (2) reduction of
toxicity, mobility, or volume through treatment, (3) short-term effectiveness, (4) implementability,
and (5) cost Each criterion is further explained in the following sections.
8.2.1 Long-Term Effectiveness and Permanence
This criterion evaluates the long-term effectiveness of alternatives in maintaining protection
of human health and the environment
Alternative 4 would provide the greatest level of long-term effectiveness and permanence
because of its engineered cover that includes a clay layer. The single-barrier cover developed
under Alternative 4 would minimize the potential for direct exposure to the landfill contents and
the potential for contaminant migration over a longer period of time than the other alternatives
considered. Alternative 3 would provide greater long-term effectiveness and permanence than
Alternative 2. The grading and placement of native soil as a cover under Alternative 3 would
increase the long-term effectiveness and permanence beyond that afforded by institutional
controls only. Alternative 1, No Action, would provide the lowest level of long-term effectiveness
and permanence relative to the other alternatives.
8.2.2 Reduction of Toxicity, Mobility, or Volume through Treatment
None of the alternatives afford any reduction of toxicity, mobility, or volume through
treatment as no elements of treatment are included in any of the alternatives.
8.2.3 Short-Term Effectiveness
In general, the alternatives requiring the least amount of on-site worker activity (e.g.,
construction) would provide the greatest degree of short-term effectiveness because they pose the
least amount of risk to site personnel and the public during remediation activities. On this basis,
since the landfills in their current condition pose no immediate threat to human health or the
environment, Alternative 1, No Action, ranks the highest of the alternatives considered.
Alternative 4 includes activities that pose the most significant risk to worker and public health
during implementation (e.g., trucking operations to transport clay materials to the INEL).
Activities associated with Alternative 3 would pose less risk to worker and public health than
Alternative 4 but more risk than Alternative 2.
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8.2.4 Implementability
Each of the alternatives considered is implementable. Alternative 1, No Action, is the most
readily implementable as it would require no activities other than groundwater monitoring (an
element of each of the developed alternatives). Alternative 4 is the least implementable because
it has the most complex construction requirements, and materials needed for the clay layer must
be obtained from off-site resources. Alternative 3 is more readily implementable than
Alternative 4 but less implementable than Alternative 2.
8.2.5 Cost
In evaluating project costs, an estimation of the net present value of capital costs and post-
closure costs is required. In accordance with CERCLA guidance (Superfund Decision Document,
EPA, 1992), the costs presented are estimates (i.e., -30% to +50%). Actual costs could vary
based on the final design and detailed cost itemization. The cost estimates for the alternatives
analyzed for the CFA landfills are presented in Table 10. Capital costs include materials and
construction; post-closure costs include monitoring. While Alternative 4 slightly increases overall
protection of human health and the environment, Alternative 3 achieves the RAOs at a
significantly lower cost
8.3 Modifying Criteria
The modifying criteria are used in the final evaluation of remedial alternatives. The two
modifying criteria are state and community acceptance. For both of these criteria, the factors that
are considered include the elements of the alternatives that are supported, the elements of the
alternatives that are not supported, and the elements of the alternatives that have strong
opposition.
8.3.1 State Acceptance
The IDHW concurs with the selected remedial alternative, Containment with a Native Soil
Cover, Institutional Controls, and Monitoring. The IDHW has been involved in the development
and review of the RI/FS report, the Proposed Plan, this ROD, and other project activities such as
public meetings.
8.3.2 Community Acceptance
This assessment evaluates the general community response to the proposed alternatives
presented in the Proposed Plan. Specific comments received during the public comment period
on the Proposed Plan are responded to in the attached Responsiveness Summary portion of this
document. Generally, comments reflected a broad range of views, from strong support for the
selected alternative to opposition and support for the No Action alternative.
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Table 10. CFA landfills alternative cost estimates3 (net present value).
Cost element
Capital
Post-closure
Total (rounded)
Alternative 1
(no action)
$338,785
$628,898
$968,000
Alternative 2
$521,711
$1,418,545
$1,940,000
Alternative 3
$2,016,821
$1,484,290
$3,500,000
Alternative 4
$11,918,186
$3,293,898
$15,212,000
a. Cost estimates assume 30 years of monitoring and maintenance. Relatively intensive
monitoring is anticipated in the first few years in order to establish the baseline data. Because it
is not known precisely what level of monitoring will be needed after the first few years, the cost
estimate assumes that the intensive monitoring continues for the entire 30 years. The actual
monitoring costs are expected to be lower than estimated. The estimates also assume installation
of one additional groundwater monitoring well ($215,000), the need for this well will be
determined during the remedial design phase.
9. SELECTED REMEDY
Based upon consideration of the requirements of CERCLA, the detailed analysis of alterna-
tives, and public comments, DOE, EPA, and IDHW have selected Alternative 3 - Uniform Con-
tainment with Native Soil Cover, Institutional Controls, and Monitoring as the most appropriate
remedy for the OU 4-12 CFA landfills. Containment with a native soil cover is believed to be the
best alternative for minimizing public risk and providing long-term protection of the SRPA.
9.1 Uniform Containment with Native Soil Cover - Description
The major components of Alternative 3 - Uniform Containment with Native Soil Cover,
Institutional Controls, and Monitoring include (1) the placement of a uniform native soil cover
over Landfills I, n, and in, (2) the implementation of institutional controls, and (3) the periodic
monitoring of groundwater, infiltration, and/or vadose zone. The selected alternative is believed
to provide the best balance of trade-offs among the alternatives with respect to the nine
CERCLA evaluation criteria. DOE, EPA, and IDHW believe the preferred alternative is
protective of human health and the environment, complies with ARARs, and is the most cost-
effective of the alternatives evaluated.
Alternative 3 ensures that a thickness of at least 2 ft of a combination of existing soil cover
and clean, compacted, native soils cover the landfills' waste. Overall design criteria for the cover
will be specified by the agencies in the RD/RA work plan. These criteria will include
requirements for hydraulic conductivity, as-built cover thickness and tolerances, erosion control,
and revegetation. The permeability of cover soils at Landfills n and ffl are 2 x 10"3 cm/sec and
2 x 10"5 cm/sec, respectively, as shown in Table 3-11 of the RI/FS. No information is currently
available for the permeability of cover soils at Landfill I as no investigation pertaining to this
42
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parameter was made during the Track 2 investigation. The existing landfills will be surveyed and
measures will be taken to provide a cover that is graded to promote efficient runoff and eliminate
low spots" where precipitation could accumulate and potentially infiltrate, into the landfill
contents. Routine maintenance of the cover will include placement of soils as needed to
eliminate low spots that may form due to landfill content subsidence. Long-term stability of the
cover will be enhanced by promoting the growth of natural vegetation at the cover's surface. The
cover will be installed using conventional earth moving equipment and measures will be taken to
minimize dust generation. The existing soils covering the CFA landfills wfll be supplemented as
necessary with native soils from a borrow site located in the southwestern portion of the INEL.
These borrow site soils have been examined and meet the permeability requirements for use as
landfill cover material. It is expected that approximately 55,000 yd3 of native soil will be brought
to the landfills.
In addition to the placement of a native soil cover, Alternative 3 will include institutional
controls. These institutional controls will include administrative controls such as placing written
notification of this remedial action in the facility land use master plan to ensure that potential
future activities would not compromise the integrity of the cover. A copy of the notification will
be given to the BLM together with a request that a similar notification be placed in the BLM's
property management records for this site. Borders will be delineated through the posting of
signs warning of the landfill existence and potentially contaminated soils.
Groundwater, infiltration, and/or vadose zone monitoring will be conducted under
Alternative 3. Groundwater monitoring would be conducted in order to (1) establish a baseline
of potential contaminant concentrations in the aquifer against which future data could be
compared, and (2) ensure that drinking water standards are not exceeded in the SRPA due to the
migration of contaminants from the landfills. Infiltration and/or vadose zone monitoring would be
conducted in order to evaluate the effectiveness of the native soil cover and/or migration of
potential contaminants from the landfills.
The agencies will review .this action, including the need for continued monitoring and the
frequency and scope thereof, within 5 years and every 5 years thereafter.
9.2 Estimated Costs for the Selected Remedy
A summary cost breakdown for Alternative 3 is presented in Table 10. These costs were
annualized where appropriate (e.g., monitoring costs) and summarized in net present value (1994)
using a 5% annual discount rate.
10. STATUTORY DETERMINATIONS
Remedy selection is based on CERCLA, as amended by SARA, and the regulations con-
tained in the NCP. All remedies must meet the threshold criteria established in the NCP: protec-
tion of human health and the environment and compliance with ARARs. CERCLA also requires
that the remedy use permanent solutions and alternative treatment technologies to the maximum
extent practicable, and that the implemented action must be cost-effective. Finally, the statute
includes a preference for remedies that employ treatment that permanently and significantly
43
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reduce the volume, toricity, or mobility of hazardous wastes as their principal element The
following sections discuss how the selected remedy meets these statutory requirements.
10.1 Protection of Human Health and the Environment
As described in Section 8.1.1, the selected remedy satisfies the criterion of overall protection
of human health and the environment by minimizing the risk of potential contaminant migration
and by preventing direct contact with the landfill waste materials. The remedy will ensure that
cumulative risks are maintained within or below the acceptable risk range of 10"4 to 10"6.
10.2 Compliance with ARARs
The selected remedy will be designed to meet all ARARs of Federal and state regulations.
The ARARs .that will be achieved by the selected remedy are noted in Section 7.2, particularly
Table 9.
10.2.1 Chemical-Specific ARARs
There were no chemical-specific ARARs identified for the CFA landfills. Regulations have
not been promulgated specific to soil cleanup levels for contaminants that may be present in soils
at the CFA landfills.
10.2.2 Action-Specific ARARs
The selected remedy triggers the applicable or relevant and appropriate requirements of
those regulations listed in Table 9. As noted in Section 72, these ARARs focus primarily on
landfill closure under RCRA as implemented by the State of Idaho under the Idaho Hazardous
Waste Management Act Additionally, Rules for the Control of Fugitive Dust and General Rules
under IDAPA 16.01.01.650 and .01.651 apply to the selected remedy.
10.2.3 Location-Specific ARARs
There were no location-specific ARARs identified for the selected remedy as there are no
known threatened and endangered species, wetlands, rivers, or floodplains located in the area of
potential remedial activities under the selected remedy. This includes those areas identified as
soil borrow areas at the INEL. Borrow areas at the INEL have been evaluated through an
environmental assessment, which determined that these areas do not impact historical and cultural
properties, nor do they impact archeological resources.
10.2.4 To-be-Considered Guidance
In implementing the selected remedy, the agencies have agreed to consider a number of-
procedures or guidance documents that are not legally binding. The following list of documents
are to be considered as guidance documents:
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OSWER 9355.0-49FS, September 1993, Presumptive Remedy for CERCLA Municipal
Landfill Sites.
OSWER 9234.2-04FS, October 1989, RCRA ARARs: Focus on Closure Requirements.
OSWER 9476.00-1, September 1982, Evaluating Cover Systems for Solid and Hazardous
Waste (Revised).
These OSWER directives provide additional guidance on the design specifications for
constructing and maintaining a cover system.
10.3 Cost-Effectiveness
Based on expected performance, the selected remedy is considered to be cost-effective. This
is evident when considering the cost of Alternative 4, Containment with a Single-Barrier Cover,
which is estimated to be over four times the estimated cost of the selected remedy, yet it is
believed that Alternative 4 would not provide significant additional benefits in terms of
protectiveness.
10.4 Use of Permanent Solutions and Alternative Treatment
Technologies to the Maximum Extent Practicable
The selected remedy represents the maximum extent to which permanent solutions and
treatment technologies can be utilized in a cost-effective manner. The selected remedy provides
protection by minimizing the risk of contaminant migration to the aquifer and limiting access to
the landfill contents. The selected remedy for the CFA landfills contains elements of EPA's
presumptive remedy for CERCLA municipal landfills. The presumptive remedy is based on
historical patterns of remedy selection and scientific and engineering evaluation of performance
data on technology implementation at similar sites.
Implementation of the selected cover remedy wfll reduce the mobility of hazardous
substances, pollutants, and contaminants from the CFA landfills. The selected remedy does not
employ alternative treatment or resource recovery technologies. The use of alternative treatment
technologies was determined to be impracticable because no on-site hot spots were identified that
could be excavated and treated effectively, and because the wastes can be reliably controlled in
place.
10.5 Preference for Treatment as a Principal Element
The statutory preference for remedies that employ treatment as a principal element will not
be met. Extraction and treatment of the landfill contents is not considered a cost-effective means
of reducing the risks to human health and the environment The identified risks will be reduced
to acceptable levels by implementing the selected remedy. The remedy, which includes
containment, monitoring, and land use controls, is based on experience from remedies
implemented at other CERCLA municipal landfills and is consistent with EPA's presumptive
remedy.
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11. NO ACTION SITES IN OPERABLE UNIT 4-03
This section of the ROD summarizes information on 19 Track 1 investigations (consisting of
underground storage tank sites) designated as "no further action" and documents the "no further
action" decision for these sites. These sites were identified in the FFA/CO for the Track 1
investigation process because they were considered low probability hazard sites and are included
in OU 4-03. Low probability hazard sites typically contain low or unknown quantities of residual
contamination. The 19 sites discussed in further detail below were identified by DOE, EPA, and
IDHW as posing no unacceptable risk to human health.
In accordance with the FFA/CO, the Track 1 process evaluates existing data and information
on the Track 1 site to determine whether the site poses an unacceptable risk to human health.
The information is assembled into a decision documentation package involving questions about
possible past containment releases and qualitative risk evaluation. The Track 1 approach is an
efficient yet rigorous process to evaluate risks. The evaluation process is used to determine if (a)
the site poses a clear risk that requires interim action, (b) the site should be further investigated
under CERCLA, or (c) the source does not appear to pose a risk to human health or the
environment and therefore requires no further action.
Except where noted, all of the tanks, their contents, and associated piping were removed.
All of the tank sites were backfilled with soil and restored for unrestricted use. In many cases,
the tank and associated piping were recycled as scrap metal. Several of the tank sites had
petroleum-related organic contamination in the soil in the bottom of the excavation. In each
case, a risk evaluation determined that the soil concentration for these contaminants did not
exceed the 1 in 1,000,000 risk-based concentrations for inhalation of volatile organic compounds
and dust, ingestion of soil, and ingestion of groundwater. A short discussion of each of the 19
underground storage tank sites follows.
CFA-18, Fire Department Training Ant Gatollne Storage Tank. This is a 500-gal
gasoline tank installed in 1952, which is still in use (and is thus subject to appropriate rules and
regulations for ongoing operations). No leakage was observed from the tank during tightness
testing performed in March 1993. Also, no contaminants have been observed near the tank.
Based on this investigation of potential past releases from the tank, no further action is
recommended.
CFA-19, Fuel Tanks at CFA-606. This is the site of two former 10,000-gal fuel tanks
installed in 1948 and last used in 1950. Tanks CFA 606-E1 and -E2 were used to store gasoline
and diesel fuel, respectively, for unknown purposes. All attempts to locate the tanks and
associated piping (with ground-penetrating radar and metal detector) were unsuccessful, and there
was no visible evidence of excavated areas or piping to the tanks. It is believed that the tanks
have been removed and the areas have been backfilled. According to records, no tank content or
soil samples were collected at this site because the tanks were not located.
CFA-20, Fuel OU Tank at former CFA-609 (near current CFA-612). This is the site of a
former 275-gal fuel tank installed in 1952 and last used in 1985. The tank was used to store fuel
oil for heating building CFA-609, which was demolished and replaced by the current CFA-612 and
46
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an adjacent asphalt parking lot Although no written record of removal was found, there was
reference to a letter stating that the tank had been excavated. Also, an equipment operator who
worked on demolition of the old CFA-609 indicated that the tank had been removed and the
excavation backfilled about 1985 or 1986. No efforts could be made in the Geld to locate the
original tank site because the tank site has been covered with a parking lot and a building. No
tank content sampling or soil sampling records could be found.
CFA-21, Fuel Tank at Nevada Circle 1 (South by CFA-629). This is a former 500-gal
gasoline tank installed in 1958 and last used in 1970. The tank and associated piping were
excavated and removed from the ground in May 1991. During removal operations, the tank was
inadvertently punctured by excavation equipment resulting in a spill of approximately 75 gal of
diesel fuel in the excavation. Contaminated soil was removed from the excavation and treated.
Approximately 60 gal of spilled fuel was retrieved and 15 gal absorbed into soil resulting in high
concentrations of total petroleum hydrocarbons in two soil samples (20,000 and 54,000 mg/kg).
However, because the volume of spilled fuel is low and total petroleum hydrocarbons are
relatively immobile in the soil, further sampling was not conducted. All other contaminants
detected in the excavation beneath the tank were below the 1 in 1,000,000 risk-based
concentrations.
CFA-23, Fuel Oil Tank at CFA-641. This is a former 55-gal fuel oil tank installed in 1949
and last used in 1975. The tank and associated piping were excavated and removed from the
ground in October 1990. No holes in the tank or piping or other evidence of leakage were
observed during removal operations. No contaminants were detected at levels that exceed the 1
in 1,000,000 risk-based concentrations.
CFA-24, Heating Fuel Tank near CFA-629. This is a former 500-gal heating fuel tank
installed in 1958 and last used in 1970. The tank (no associated piping was found) was excavated
and removed from the ground in May 1991. No holes in the tank or other evidence of leakage
was observed during removal operations. No contaminants were detected at levels that exceed
the 1 in 1,000,000 risk-based concentrations.
CFA-25, Fuel OH Tank at CFA-6S6. This is a former 500-gal fuel oil tank installed in 1944
and last used in 1960. The tank and associated piping were excavated and removed from the
ground in October 1990. No evidence of leakage was observed from the tank or associated piping
during removal operations. No contaminants were detected in the excavation beneath the tank
above the 1 in 1,000,000 risk-based concentrations.
CFA-27, Fuel Oil Tank at CFA-669 (CFA-740). This is a former 15,000-gal fuel oil tank
installed in 1953 and last used in 1981. The tank and associated piping were excavated and
removed from the ground in October 1990. Evidence of leakage from the piping was observed
during removal operations; however, there was no evidence of leakage from the tank.
Contaminated soil was removed and treated. No contaminants were detected in the excavation
beneath the former tank or piping above the 1 in 1,000,000 risk-based concentrations.
CFA-28, Fuel Oil Tank at CFA-674 (West). This is a former 1,000-gal fuel oil tank
installed in 1956 and last used in 1968. The tank was excavated and removed from the ground in
September 1992. No evidence of leakage was observed from the tank during removal operations.
47
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No contaminants were detected in the excavation beneath the tank above the 1 in 1,000,000 risk-
based concentrations.
CFA-29, Waste OH Tank at CFA-664. This is a former 1,000-gal waste oil tank installed in
1951 and last used in 1989. The tank and associated piping were excavated and removed from
the ground in October 1990 after it failed a tightness test Soil contamination observed in the
excavation was removed and treated. No contaminants were detected in the excavation beneath
the tank above the 1 in 1,000,000 risk-based concentrations.
CFA-30, Waste Oil Tank at CFA-665. This is a former 1,000-gal waste oil tank installed in
1960 and last used in 1989. The tank and associated piping were excavated and removed from
the ground in September 1989 after it failed a tightness test Soil contamination observed in the
excavation was removed and treated. No contaminants were detected in the excavation beneath
the tank above the 1 in 1,000,000 risk-based concentrations.
CFA-31, Waste OH Tank at CFA-754. This is a former 15,000-gal tank used as bulk storage
of waste oil. The date of installation is unknown; however, it was last used in 1985. The tank
and associated piping were excavated and removed from the ground in May 1992. Contaminated
soil observed in the excavation during removal operations was removed and treated. After
removal of contaminated soil, no contaminants were detected in the excavation beneath the tank
above the 1 in 1,000,000 risk-based concentrations.
CFA-32, Fuel Oil Tank at CFA-667 (North Side). This is a former 180-gal fuel oil tank last
used in 1986. The date of installation of this tank is unknown. The tank and associated piping
were excavated and removed from the ground in October 1990. No evidence of leakage from the
tank or piping was observed during removal operations. No contaminants were detected in the
excavation beneath the former tank or piping.
CFA-33, Fuel Tank at CFA-667 (South Side). This is a former 4,000-gal diesel fuel tank
installed in 1951 and last used in 1986. The tank and associated piping were excavated and
removed from the ground in October 1990. Soil contamination observed near the filling port of
the tank was removed and treated. No evidence of leakage was observed from the tank or
associated piping during removal operations. No contaminants were detected in the excavation
beneath the tank above the 1 in 1,000,000 risk-based concentrations.
CFA-34, Diesel Tank at CFA-674 (South). This is a former 260-gal diesel fuel tank
installed in the early 1950s and last used in 1976. The tank and associated piping were excavated
and removed from the ground in October 1990. The tank contained several holes and leaked
some of its contents into the surrounding soil. Soil contamination observed in the excavation was
removed and treated. No contaminants were detected in the excavation beneath the tank above
the 1 in 1,000,000 risk based concentrations.
CFA-35, Sutfuric Add Tank at CFA-674 (West Side). This is a former 1,000-gal sulfuric
acid storage tank installed in 1953 and last used in 1965. The tank and associated piping were
excavated and removed from the ground in June and July 1989. No evidence of leakage was
observed from the tank or associated piping during removal operations. No contaminants were
detected in the excavation beneath the tank above the 1 in 1,000,000 risk-based concentrations.
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CFA-36, Gasoline Tank at Building CFA-680. This is a former 55-gal gasoline tank
installed in 1951 and last used in 1983. The tank and associated piping were excavated and
removed from the ground in October 1990. No evidence of leakage was observed from the tank
or associated piping during removal operations. No contaminants were detected in the excavation
beneath the tank above the 1 in 1,000,000 risk-based concentrations.
CFA-37, Fuel Oil Tank at CFA-681 (South Side). This is a former 500-gal fuel oil tank
installed in 1949 and last used in 1978. The tank and associated piping were excavated and
removed from the ground in October 1990. Small holes and rust were observed in the tank
during removal operations. Contaminated soil was removed from the excavation and treated. No
contaminants were detected in the excavation beneath the tank above the 1 in 1,000,000 risk-
based concentrations.
CFA-38, Fuel OH Tank at CFA-663. This is a former 500-gal fuel oil tank installed in 1949
or 1950 and last used in 1980. The tank and associated piping were excavated and removed from
the ground in May 1992. No evidence of leakage was observed from the tank or associated
piping during removal operations. No contaminants were detected in the excavation beneath the
tank above the 1 in 1,000,000 risk-based concentrations.
12. DOCUMENTATION OF SIGNIFICANT CHANGES
The proposed plan for the CFA landfills was released for public comment in April 1995.
The proposed plan identified Alternative 3uniform containment with native soil cover,
institutional controls, and monitoringas the preferred alternative. The agencies reviewed all
written and verbal comments submitted during the public comment period. Upon review of these
comments and preparation of the ROD, it was determined that no significant changes to the
remedy would be required.
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Appendix A
Responsiveness Summary
A-l
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Appendix A
Responsiveness Summary
A.1 OVERVIEW
Operable Unit (OU) 4-12 is an OU within Waste Area Group (WAG) 4 of the Central
Facilities Area (CFA) at the Idaho National Engineering Laboratory (INEL). The unit comprises
CFA Landfills I, n, and ffl, as described in the Record of Decision (ROD) to which this
Responsiveness Summary is attached. A Proposed Plan was released April 24, 1995, with a public
comment period from April 26 to May 26, 1995. The preferred alternative recommended includes
uniform containment of the landfills with a native soil cover, institutional controls, and
monitoring. This Responsiveness Summary recaps and responds to the eight comments received
during the comment period. Generally, the comments reflected a broad range of views, from
strong support for the selected alternative to opposition and support for the no action alternative.
A.2 BACKGROUND ON COMMUNITY INVOLVEMENT
To initiate the CFA Landfills investigation, public information meetings were held in August
1993 in Boise, Moscow, Twin Falls, Pocatello, and Idaho Falls. The information meetings were
designed to involve the public early in the investigation; explain the Comprehensive
Environmental Response, Compensation, and Liability Act (CERCLA) process; allow
representatives from DOE and INEL to discuss the project; answer both written and verbal
questions; and receive ideas and suggestions from the public.
Copies of the proposed plan for the CFA landfills were mailed to about 6,700 members of
the public and 650 INEL employees on the INEL Community Relations Plan mailing list on
April 24, 1995 urging citizens to comment on the proposed plan and to attend public meetings.
Opportunities for public involvement in the decision process for the CFA landfills were provided
during the 30-day comment period from April 26 to May 26, 1995. For the public, the activities
ranged from receiving the proposed plan, conducting one teleconference call, and attending open
houses and public meetings to informally discuss the issues and offer verbal and written comments
to the agencies during this 30-day public comment period.
Written comment forms, including a postage-paid business reply form, were made available
to those attending the meetings. The forms were used to turn in written comments at the
meeting, and by some, to mail in comments later. For those who did not attend the public
meetings but wanted to make formal written comments, a written comment form was attached to
the Proposed Plan. A total of about ten people attended the CFA landfills public meetings.
Overall, eight provided formal comment; of these eight people, three provided oral comments and
five provided written comments.
A-3
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This Responsiveness Summary has been prepared as pan of the ROD. All formal verbal
comments, as given at the public meetings, and all written comments, as submitted, are repeated
verbatim in the Administrative Record for the ROD. Those comments are annotated to indicate
which response in the Responsiveness Summary addresses each comment The ROD presents the
preferred alternative for the CFA landGlls, selected in accordance with CERCLA, as amended by
the Superfund Amendments and Reauthorization Act (SARA) and, to the extent practicable, the
National Oil and Hazardous Substances Pollution Contingency Plan (NCP). All comments
received on the proposed plan were considered during the development of this ROD. The
decision for this OU is based on information contained in the Administrative Record.
A.3 SUMMARY OF COMMENTS RECEIVED
DURING PUBLIC COMMENT PERIOD
Comments and questions raised during the public comment period on the CFA LandGlls
Proposed Plan are summarized below. The public meetings were divided into an informal
question-and-answer session and a formal public comment session. The meeting format was
described in published announcements and meeting attendees were reminded of the format at the
beginning of each meeting. The informal question-and-answer session was designed to provide
immediate responses to the public's questions and-concerns. Several questions were answered
during the informal question-and-answer period during the public meetings on the Proposed Plan.
This Responsiveness Summary does not attempt to summarize or respond to issues and concerns
raised during that part of the public meeting. However, the Administrative Record contains
complete transcripts of these meetings, which contain the agencies' responses to these informal
questions.
Comments received during the formal comment session of the meeting were responded to
by the agencies in this Responsiveness Summary. The public was requested to provide their
formal comments on the Proposed Plan either during the formal comment session of the meeting
or in writing before the close of the public comment period. This Responsiveness Summary
responds to those public comments that were recorded by the court reporter during the.formal
comment portion of the public meeting or that were submitted in writing before the close of the
public comment period.
1. Comment: Alternative 3 seems to be the most logical choice.
Response: Thank you for your comment. Alternative 3 is the preferred alternative by the
agencies and will provide the appropriate level of protection for the public health and
welfare and the environment.
2. Comment: There is too much time, money, and energy spent on the cleanup process to try
to satisfy the anti-nukes. Most people aren't concerned until the news media gives time to
the anti-nukes and continue to spread their propaganda. Left alone, it will deteriorate and
cause no problems. Disturbing it stirs up more problems. I favor alternative 1.
A-4
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Response: Thank you for your comment. Alternative 1 was not preferred because it does
not meet the state's requirements for closing landfills such as minimizing erosion and
infiltration. The preferred alternative 3 will not disturb the existing waste since the waste
will be left in place and native soil from the INEL will be brought to the landfills and placed
over the existing soil covers to enhance the cover thickness and regraded to minimize erosion
and infiltration. Furthermore, alternative 3 uses the collective experience from other
CERCLA municipal landfills to address the uncertainty associated with wastes disposed and
with potential risks by implementing elements of the presumptive remedy approach (i.e.,
containment and monitoring to ensure effectiveness of the remedy).
3. Comment: With regards to Landfills I, n, and in, I would want to save money by opting for
something b'ke alternative 2, while doing as much as possible on SL-1 and BORAX-I. My
main concern is protection of the groundwater and continued importation of toxic wastes
into Idaho. I am also concerned for the safety and health of workers engaged in cleanup
operations.
Response: Thank you for commenting. Alternative 2 was not preferred because it does not
meet the state's requirements for closing landfills such as minimizing erosion and infiltration.
Alternative 2 would save money, but would not be as protective to the groundwater as
alternative 3, which reduces infiltration. The remedial action will be designed to ensure that
the safety and health of workers will not be compromised at any time.
4. Comment- Alternative 3 seems adequate.
Response: Thank you for commenting. Alternative 3 is the preferred alternative by the
agencies and will provide the appropriate level of protection for the public health and
welfare and the environment
5. Comment: I am very concerned with the attitude of the DOE (the agencies) and those at
INEL regarding the storage of hazardous waste near the area of our State's aquifer. Even if
your plans for storage are temporary (translated as 100 years or less), how can we ever be
assured that your "expertise" will not lead to the contamination of the soil, water supplies,
and ultimately all who are affected by the water supply running through Southern Idaho? ...
Please do not participate in contaminating Idaho with nuclear waste!
Response: Thank you for commenting. The CFA landfills are nonradioactive waste disposal
facilities that were used for the disposal of INEL municipal type waste (Le., cafeteria
garbage, trash sweepings, weeds and grass, etc.). However, some low-level radioactive waste
may have been inadvertently disposed to the landfills. Alternative 3 is the preferred
alternative because it will minimize potential infiltration and possible subsequent leaching to
the aquifer. Periodic monitoring will monitor the effectiveness of the cover and provide for
the detection of contaminants in the groundwater if migration occurs.
6. Comment: My comments before somewhat apply, and I've got some additional ones. The
risk here seems to be again for a residential scenario, and it's beryllium, two in 10,000. Let's
get the land use for these things before we go off and spend a big bunch of money.
A-5
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What are we going to do? Is this thing going to be industrial? Is this going to be farming?
What's it going to be, so we really know what the risk is? I heard Alan say no risk, but due
to the uncertainty we're going to spend $2 million more a year plus 60k a year more, I like
action No. 1, which is No Action or Alternative No. 1, which happens to be No Action if
we've got models and codes that can predict what's going on and have been benchmarked
and validated.
Why spend the money if we've got the confidence? If we're just trying to cover ourselves
because of uncertainties so we throw in this Alternative 3 here, it doesn't seem like the right
thing, and I don't believe we're protecting the public.
This has been DOE's credibility problem from day one. Let's get it down to where we got
confidence in what we're doing. And if it takes computer codes that are benchmarked and
validated, let's do it My suggestion is let's get the National Academy of Sciences out here.
They were out here looking at some of this stuff before.
Let's specifically have them look at some of these codes and the way we're doing things so
that we've got some confidence in it If the risk is really less than one in 10,000, then let's
go with the No Action on it. There's no need to go with the Alternative 3 and spend the
additional money. If it's needed and warranted, certainly we want to do it But let's get the
risk down to where we really know what it is. And my suggestion is let's get an independent
reviewer in here, and perhaps the National Academy of Sciences is the way to start
Response: Thank you for commenting. The risk assessment is based on a current worker
and a potential future resident scenario. It is common practice, based on EPA guidance, to
examine a potential future residential land-use scenario. We do not know at this time what
actual land uses of the INEL will be in the future. Therefore, it is important to use a
conservative land-use scenario, i.e., residential scenario to fully assess potential future
impacts for decision-making purposes.
Alternative 1 was not the preferred alternative because it does not meet the applicable or
relevant and appropriate requirements such as minimizing erosion and infiltration.
Alternative 3 is the preferred alternative by the agencies and will meet the applicable or
relevant and appropriate requirements and provide the appropriate level of protection for
the public health and welfare and the environment.
The computer code GWSCREEN, validated and accepted by the agencies, was used during
the remedial investigation of the landfills to address future groundwater concerns, as a result
of potential future leaching of the source term to the groundwater, and indicated no
unacceptable groundwater health risk to potential future residents. However, uncertainties
in the landfill waste inventory (source term) lead to uncertainties in the modeled
groundwater health risk. The Site-Specific Advisory Board provides some independent
review of CERCLA investigations and cleanup at the INEL.
Due to the heterogeneous nature of the waste and incomplete inventory of waste disposal,
complete characterization of the landfill contents was and is not expected. Therefore, future
use of the landfills that may involve excavation of the landfill subsurface materials could
A-6
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increase risks of exposure to contaminants (via inhalation, ingestion, and dermal contact) for
potential future construction workers and residents.
7. Comment: I like the preferred alternative. I think that I'm not opposed to it in any way,
shape, or form. I think it's not much different than any other waste site as far as a dump
site that would be in an urban area. I think that in my opinion that the Area 1, because of
the uncertainty of what was put in there, I think that there needs to be a little more work
done on that particular area in those trenches. And I think that we need to be a little
more - I would like to be a little more sure what is in there is not in 50-gallon barrels
decaying as we speak and that we're just closing our eyes to it.
But I think I would like to congratulate everybody on this work that has been done all night.
I think all the work that has been done is reaUy exemplary. And once again, the preferred
Alternative No. 3, that's the only alternative I can see that makes sense.
The No. 4,1 think that would just slow down the decay process and cause it ~ and maybe
that would be a question as to whether or not we'd have an erosion problem or sooner or
later down the road and we would have- for the problems 50 years from now, I think its
better to let it decay in a natural way. It needs some water. I think that we need to use the
flora that's indigenous to the area in case this area is abandoned for budgetary reasons. And
I think that we need to have guarantees as to the native soil at least 4 to 6 inches of topsoil.
Being a horticulturist, I know that it would take at least 4 inches to establish a decent plant
growth on top of it I wouldn't ask that all 2 feet be topsoil, because that would be
ludicrous, but the top 4 to 6 inches, I think we need to maintain that That's all I want to
say.
Response: Thank you for commenting. Alternative 3 is the preferred alternative by the
agencies and will meet the applicable or relevant and appropriate requirements and provide
the appropriate level of protection for the public health and welfare and the environment
During the remedial investigation phase of the project, an extensive source term
investigation was conducted by compiling and reviewing available waste disposal records,
documents, databases, and process knowledge, and by conducting interviews with personnel
knowledgeable in CFA landfill operations to determine the waste types and volume disposed
to the landfills. It was not common practice to dispose of 55-gallon drums full of oil or any
liquid in the landfills. Drums disposed to the landfill were typically empty, or if liquid was
present, it was absorbed onto diatomaceous earth or rags. In some instances, waste oil was
disposed to the landfill directly by dumping it over the solid waste and mixing with a layer of
soil. In some instances, the oil was used to bum paper wastes in trenches. The use of the
incinerator at Landfill I to burn waste, coupled with the open burning of wastes in the
trenches, would have greatly reduced the volume and the potentially hazardous components
present in waste oil or solvents.
Experience from other CERCLA municipal landfills shows that it is more cost-effective to
implement the presumptive remedy of containment because it is impossible to fully
characterize the landfill contents. Periodic environmental monitoring will monitor the
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effectiveness of the cover and provide for the detection of contaminants in the groundwater
if migration occurs.
The remedial design of the cover will allow for 6 inches of topsoil to ensure the
establishment of a vegetative top layer.
Comment: I might suggest that you try some kind of meeting in the Twin Falls area because
of the huge amount of interest there is in that area about the groundwater. It might be
good to have one more in that southern part of the state.
Response: Thank you for your suggestion. In the past, the agencies have had informal
briefing meetings in Twin Falls. The feedback from the residents of this area who attended
past meetings is that they don't want any more meetings. Public relations representatives
were also available for an afternoon at the public library to answer any questions the public
had concerning the project Due to the lack of interest from the public in this area and
budget cuts, a public meeting was not scheduled for the Twin Falls area. However, public
meetings may be held in the future in the Twin Falls area, as has been done in the past
A-8
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Appendix B
Public Comment/Response List Index
B-l
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Appendix B
Public Comment/Response List Index
The Public Comment/Response List (Table B-l) was created to enable commenters and
other interested persons to locate the agencies' responses to individual public comments.
Each comment had been assigned a comment code. The codes indicate whether the comment
was either written (W code) or taken from the public meeting transcript (T code). Five people
submitted written comments (comments W1-W5) and three others gave oral comments at the
public meetings (comments T1-T3). Copies of oral and written comments annotated with their
respective comment codes are located in the Administrative Record.
To locate a response to a specific individual's comments, look up the last name of the
individual, then turn to the response number or page indicated in the Responsiveness Summary
(Appendix A). If, after reviewing the annotated comments in the administrative record, you wish
to locate a response to a specific comment, you can use the comment code to locate a response as
well. Identify the comment code in the index, look up the page number of the response, then
turn to that page of the Responsiveness Summary.
Table B-1. Public comments received on the CFA landfills during the April 26 through May 26,
1995 comment period.
Comment code
W-l
W-2
W-3
W-4
W-5
T-l
T-2
T-3
Response number
5
1
2
4
3
6
7
8
Commenter
Jim Sommer
D.R-Mix
Dorothy Strait
Albert Taylor
George Lukes
Robert Wadkins
Bruce Allen
Twila Hornbeck
Page number for response
A-5
A-4
A-4
A-5
A-5
A-5
A-7
A-8
B-3
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