U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF INSPECTOR GENERAL
Catalyst for Improving the Environment
Hotline Report
Contaminated Soil Waste Repository
at East Mission Flats, Idaho
Report No. 09-P-0162
June 8, 2009
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Report Contributors:
Eric Lewis
Dan Cox
Tom Reilly
Johnny Ross
Kathryn Hess
Kimberly Crilly
Abbreviations
BEIPC Basin Environmental Improvement Project Commission
CERCLA Comprehensive Environmental Response, Compensation, and Liability Act
EMF East Mission Flats
EPA U.S. Environmental Protection Agency
IDEQ Idaho Department of Environmental Quality
OIG Office of Inspector General
ROD Record of Decision
SVCRC Silver Valley Community Resource Center
Cover photo:
The planned East Mission Flats contaminated soil waste repository location.
(Photo taken by OIG staff in May 2008)
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I
U.S. Environmental Protection Agency
Office of Inspector General
At a Glance
09-P-0162
June 8, 2009
Catalyst for Improving the Environment
Why We Did This Review
We conducted this review to
determine if the U.S.
Environmental Protection
Agency (EPA) allowed
appropriate community
involvement and provided
adequate notice when selecting
the East Mission Flats (EMF),
Idaho, repository location; and
included flood controls in
repository design to minimize
potential for releasing
contaminants.
Background
An environmental organi-
zation located in Kellogg,
Idaho, complained to the
Office of Inspector General
(DIG) Hotline that EPA did
not follow Superfund
requirements in designing the
repository. The group alleged
the public was not notified
appropriately of repository
plans and did not have an
opportunity to provide
comments.
Contaminated Soil Waste Repository at
East Mission Flats, Idaho
What We Found
EPA Region 10 and the Idaho Department of Environmental Quality (IDEQ)
provided opportunities for the community to become involved and notified the
public when selecting the East Mission Flats repository site location and soliciting
comments on the proposed plan, location, and designs.
We found that many physical aspects of flooding have been investigated and
considered in the design process. However, we also found that the geochemical
aspects and potential for releasing dissolved contaminants had yet to be
investigated. The proposed repository site is located in an area that floods
annually. Region 10 and IDEQ have not sufficiently analyzed the geochemical
conditions that are expected to form near the repository base, the potential for
annual flooding to introduce water into the repository, and the possibility that
dissolved contaminants will migrate away from the repository. In response to our
concerns, Region 10 and IDEQ prepared a draft scope of work for the needed
analysis. Much of that work was completed and included in Region 10's response
to our draft report. But the work leaves unresolved the amount of water that will
be introduced into the repository with flooding and rising groundwater levels.
What We Recommend
We recommended that EPA Region 10 finish analyzing the geochemical and
physical conditions that may lead to contaminants dissolving near the repository
base; then confirm the adequacy of the repository design to prevent dissolved
contaminants from being released under these conditions.
For further information,
contact our Office of
Congressional, Public Affairs
and Management at
(202)566-2391.
To view the full report,
click on the following link:
www.epa.gov/oig/reports/2009/
20090608-09-P-0162.pdf
Region 10 concurred with the recommendation and prepared a technical analysis.
We acknowledge that the new work is extensive, especially the unsaturated zone
modeling. However, the Region's analysis included assumptions, with consequent
conclusions, that the OIG believes require technical verification. The Region
should address these issues in its 90-day response to the final report. The
recommendation will remain open.
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09-P-0162
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
OFFICE OF
INSPECTOR GENERAL
June 8, 2009
MEMORANDUM
SUBJECT:
FROM:
TO:
Contaminated Soil Waste Repository at East Mission Flats, Idaho
Report No. 09-P-0 162
Wade T. Najjum
Assistant Inspector General
Office of Program Evaluation
Michelle Pirzadeh
Acting Regional Administrator
Region 10
This is our final report on the subject review conducted by the Office of Inspector General (OIG)
of the U.S. Environmental Protection Agency (EPA). This report contains findings that describe
concerns the OIG has identified and corrective actions the OIG recommends. This report
represents the opinion of the OIG and the findings contained in this report do not necessarily
represent the final EPA position. Final determinations on matters in this report will be made by
EPA managers in accordance with established resolution procedures.
The estimated cost of this report - calculated by multiplying the project's staff days by the
applicable daily full cost billing rates in effect at the time - is $418,288.
Action Required
In accordance with EPA Manual 2750, you are required to provide this office with a written
response within 90 days of the date of this report. You should include a corrective action plan
for agreed-upon actions, including milestone dates. We have no objections to the further release
of this report to the public. This report will be available at http://www.epa. gov/oig.
If you or your staff have any questions regarding this report, please contact Eric Lewis at
202-566-2664 or lewis.eric@epa.gov, or Tom Reilly at 202-566-2897 or reilly.tom@epa.gov.
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Contaminated Soil Waste Repository at 09-P-0162
East Mission Flats, Idaho
Table of Contents
Purpose 1
Background 1
Scope and Methodology 3
Results of Review 4
Notification and Community Involvement 4
Evaluating the Potential for Contaminant Release 6
Recommendation 9
Agency Comment and OIG Evaluation 9
Status of Recommendation and Potential Monetary Benefits 10
Appendices
A Agency Responses 11
B OIG Comments 21
C Distribution 26
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09-P-0162
Purpose
The purpose of this review was to determine whether an OIG Hotline complaint that the
Silver Valley Community Resource Center (SVCRC) submitted to the U.S.
Environmental Protection Agency (EPA) Office of Inspector General (OIG) had merit.
In conducting this review, we pursued the following questions:
1. Did EPA Region 10 and the Idaho Department of Environmental Quality
(IDEQ) allow for appropriate community involvement in selecting the
repository site location and providing comments on the proposed plan and
repository designs?
2. Did Region 10 and IDEQ provide adequate public notification regarding
the waste repository proposed for East Mission Flats (EMF)?
As a result of the community concerns and our own observations, we pursued an
additional objective:
3. Did Region 10 and IDEQ incorporate flood controls in the repository
design to minimize potential for contaminant release?
Background
SVCRC, an environmental organization located in Kellogg, Idaho, submitted a complaint
to the OIG Hotline. SVCRC alleged that EPA did not follow Comprehensive
Environmental Response, Compensation, and Liability Act (CERCLA) requirements in
designing the EMF repository. The repository is located close to the Old Mission
National Historic Landmark and State Park near Cataldo, Idaho, in an area that floods
every spring. SVCRC alleged the public did not receive appropriate notification of the
repository plans and did not have sufficient opportunity to provide comments.
Community members were also concerned that contaminants from the repository might
migrate from the site during annual flooding.
The EMF repository site (see Figures 1 and 2) encompasses a 23-acre parcel of land
about % of a mile west of Cataldo, Idaho. The repository site is 1,500 feet from Old
Mission State Park and about 3,000 feet from the Coeur d'Alene River. Interstate 90
separates the site from the park and the river.
Sediments at the repository site are already contaminated. Contamination within the river
basin includes source areas of mine and mill sites in the upper South Fork of the Coeur
d'Alene River valley and deposits of mining waste on the 100-year floodplain in the
lower river valley, west of Cataldo.
The repository will hold about 416,000 cubic yards of soils contaminated with lead,
arsenic, and other metals. Remedial actions in the Bunker Hill Mining and Metallurgical
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Complex (Bunker Hill) Superfund Site (Operable Unit 3) will generate these soils. In
response to public comments on the 30% Design Report, EPA Region 10 and IDEQ
reduced the planned height of the repository from 62 feet to 34 feet to eliminate direct
sight lines from the park to the top of the repository.
Figure 1. Aerial photo of repository site location.
(Source: Mapquest.com website)
Figure 2. EMF Repository Site - December 2007
(Source: OIG staff photo)
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When Congress passed CERCLA, also known as Superfund, in 1980, it incorporated
public involvement into the remediation process. Congress intended to ensure that the
people whose lives were affected by hazardous wastes and EPA's actions to clean them
up would have a say in what happened in their community.
Since then, Congress further strengthened the role of community members through
passage of the Superfund Amendments and Reauthorization Act of 1986, and EPA,
through its administrative reforms. While EPA retains the final responsibility and
authority to decide what will happen at a Superfund site, the Agency must consider
community input.
The goal of EPA's Superfund Community Involvement Program under CERCLA is to
advocate and strengthen early and meaningful community participation during site
cleanups. Superfund community involvement staff strive to keep the community well
informed of ongoing and planned activities, encourage and enable community members
to get involved, and listen carefully to what the community is saying. EPA's community
involvement efforts, through its Community Involvement Plans for specific Superfund
sites, fulfill the statutory and regulatory requirements of CERCLA, as well as the intent
of the law.
The Community Involvement Plan for Operable Unit 3 of the Bunker Hill Site outlined
community involvement goals and proposed avenues such as local newspapers, public
meetings, and fact sheets, to provide information to the public.
The Record of Decision (ROD) for Operable Unit 3 directs EPA to initiate a public
outreach effort to give citizens and stakeholders an opportunity to comment on the
location and design of proposed repositories. This outreach effort was to be concurrent
with the technical evaluation of potential repository sites.
Scope and Methodology
We performed work on this assignment from December 2007 through March 2009. We
interviewed the complainants, local residents, employees in EPA Region 10 and the
Idaho Department of Environmental Quality, representatives of the Coeur d'Alene Tribe,
members of the Basin Environmental Improvement Project Commission, and staff from
the Center for Justice. We visited the planned repository site in East Mission Flats,
Idaho, during May 2008 and observed that the site was inundated with several feet of
water. We attended an "open house" conducted by IDEQ and Region 10 in July 2008 to
update interested local residents on design plans for the repository. We reviewed site
administrative files, community relations files, cleanup planning documents, and the
intermediate design reports, referred to as the 30% and 60% Design Reports.
We performed this review in accordance with generally accepted government auditing
standards as issued by the Comptroller General of the United States. We limited our
review of management controls and compliance to those directly relating to the issues
identified in the hotline complaint.
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09-P-0162
Results of Review
Notification and Community Involvement
Region 10 provided adequate opportunities for public comment on the ROD
Region 10 provided adequate opportunities for the public to comment on the ROD for
Operable Unit 3 of the Bunker Hill Superfund site which was issued in September 2002.
EPA received more than 3,300 comments on the proposed Basin Cleanup Plan from
approximately 1,300 different individuals.1 EPA extended the comment period twice, for
a total of 120 extra days, in response to public requests. Part 3 of the ROD contains the
summaries of public comments and the EPA responses.
The Region published a Community Involvement Plan for the Coeur d'Alene Basin and
Bunker Hill Superfund site in August 2005. Consistent with the plan, EPA and IDEQ
provided information on ongoing cleanup efforts in the Bunker Hill complex through the
Basin Environmental Improvement Project Commission (BEIPC)2, the Citizens
Coordinating Council3, town hall meetings, Internet sites, newspapers, and a door-to-door
campaign informing community members of ongoing cleanup efforts.
Region 10 and IDEQ met ROD community involvement requirements in
siting the repository
During January and February 2005, EPA and IDEQ representatives went door-to-door to
discuss with seven individuals living near the site the potential for siting a repository at
East Mission Flats. The IDEQ representative also contacted one individual by phone, left
handouts at four residences, and mailed certified letters and handouts to two individuals.
Region 10 and IDEQ also discussed, during a July 2005 town hall meeting which 19
community members attended, the possibility that a repository could be sited at East
Mission Flats. At this meeting, the Region and IDEQ indicated that attendees were
welcome to provide written or verbal comments regarding the siting of the repository.
During an October 2005 town hall meeting, Region 10 again indicated that there was an
urgent need to site more repositories in the Coeur d'Alene Basin and asked the Citizens
Coordinating Council for help in identifying appropriate locations. The Region also
noted that efforts were ongoing to investigate whether a repository could be sited at
"Mission Flats."
1 Ombudsman Review of Bunker Hill and Coeur d' Alene Basin Superfund Actions; OIG Report No. 2004-
P-00009, March 24, 2004.
2 The Coeur d'Alene Basin Environmental Improvement Project Commission (BEIPC) was established
when the ROD was issued for Operable Unit 3.
3 The Citizens Coordinating Council was formed as a sub-group under the BEIPC to provide a mechanism
for the community and other interested stakeholders to obtain information on site plans and activities and
express their concerns.
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In the December 2006 Basin Bulletin, Region 10 published an article indicating that
IDEQ had purchased property at East Mission Flats in September 2006 and, jointly with
Region 10, was proceeding to design a new repository at that location.
Region 10 and IDEQ met ROD community involvement requirements in
designing the repository
In designing the repository, Region 10 and IDEQ adequately addressed the ROD's
community input/notification requirements. Region 10, IDEQ, and BEIPC conducted
several public meetings where they provided information on the design of the EMF
repository. For example, they:
• sponsored a community meeting at the Canyon School in March 2006,
• presented information on the repository at a Citizens Coordinating Council
meeting in May 2006,
• made update presentations at Citizens Coordinating Council meetings in
February and May 2007,
• provided a public tour of the EMF site in June 2007, and
• held a discussion on the 30% Design Report at the Canyon School in
October 2007.
The public was given the opportunity to submit comments on the 30% Design Report
between May 16 and July 6, 2007. Among those providing comments on the design were
the Coeur d'Alene Tribe, Center for Justice, Idaho Conservation League, SVCRC, and
the Lands Council. In response to the public comments received on the 30% Design
Report, Region 10 and IDEQ made several changes to the repository design. For
example,
• The height was reduced from 62 to 34 feet for a maximum top elevation of
2,165 feet.
• The volume was reduced from about 668,000 to 416,000 cubic yards.
• Perimeter protection will now be installed as soon as the perimeter of the
repository is built to an elevation of 2,152 feet. This change was expected
to permanently protect the site from erosion due to flooding.
• Temporary protection steps are to be taken to protect the placed soils from
eroding while the repository is open.
• The existing gate is to be replaced with a key card for controlled and
monitored access to control what materials are disposed of at the
repository.
IDEQ and Region 10 also held a community "open house" on July 31, 2008, where the
public was invited to review and give suggestions on the executive summary of the 60%
Design Report for the EMF repository. The public was given the opportunity to submit
written comments through September 8, 2008.
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Evaluating the Potential for Contaminant Release
The complainant and other local citizens raised concerns regarding potential release of
contaminants from the repository that might result from flooding. The proposed
repository will be built on the floodplain of the Coeur d'Alene River. The area is known
to flood annually, although the magnitude of that flooding varies year to year. At a
minimum, water is expected to cover over half of the lower perimeter of the repository
for several weeks during the annual run-off period. When OIG personnel visited in May
2008, the site was under several feet of water (see Figure 3). We reviewed the 30% and
60% Design Reports to determine the degree to which the repository has been designed to
prevent contaminants leaving the repository by being eroded or dissolved by flood waters
that penetrate the repository and then drain away.
We found that many of the physical aspects of flooding had been considered in the design
process. However, we also found that:
• the geochemical and physical conditions that might lead to contaminants
dissolving near the repository base had yet to be investigated, and
• the adequacy of the repository design to prevent dissolved contaminant release
had yet to be evaluated.
(Source: OIG staff photo)
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Potential Erosion of Repository Waste Materials
The latest repository design included armoring the sides of the repository to protect the
repository waste materials from being carried away by flood waters. Compacting the
waste materials as the repository is constructed will also make erosion less likely. The
design specifications were to prevent erosion of the repository waste materials under the
maximum velocity and shear stress expected in a flood of a magnitude estimated to occur
once every 100 years. Estimates of stress were made using a numerical model
constructed to simulate the hydraulic effects of flooding at the repository site. The
construction plan for the armoring was modified to include annual construction stages
with the intent of preventing erosion of repository materials throughout the many years
that the repository is expected to be open to receive new waste soils.
We found that the design team had considered the potential for erosion of the repository
materials, and incorporated into the repository design elements that will lessen the
likelihood that erosion will occur under the expected conditions.
Potential Geochemical Mobilization of Contaminants
IDEQ and Region 10 have not evaluated the physical and geochemical changes that will
develop within and below the repository because the site floods annually. The 60%
Design Report and the October 2008 response to comments received on the report
suggest several issues that we detail below.
We found that the October 2008 response dismisses concerns regarding the potential for
metals to leach from the repository into the underlying groundwater. The primary
argument provided is that the metal concentrations in the underlying groundwater are
below drinking water standards, even though the top 2 to 4 feet of soils at the repository
site have been contaminated for decades. However, not far from the repository site,
where the thickness of contaminated soils is much greater due to historic dredge and
dump activities, the groundwater concentrations, according to Appendix B of the 60%
Design Report, were more than twice the ecological standard for zinc. As a result, adding
over 30 feet of contaminated soils may potentially contaminate the groundwater under
and beyond the repository if adequate mitigation steps are not incorporated into the
repository design. We also found the argument given did not consider changes in the
geochemical conditions that are anticipated to occur within and underneath the
repository.
The October 2008 response also reports that the repository cap will practically eliminate
infiltration from precipitation into the compacted, contaminated materials. However, this
response does not acknowledge that the infiltration cap does not extend down the sides of
the repository where the contaminated materials will be capped instead by gravel and
other armoring materials. Nor does the response consider that a liner will not be placed
at the repository base, even though the groundwater level is known to rise above land
surface annually with the flooding. No barriers will be present to prevent flood waters
from infiltrating into the repository materials from the side and from underneath.
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The metals in the repository materials will be fairly stable, except under the reduced
geochemical conditions4 that are expected to occur near the repository base, according to
the 60% Design Report. The report suggests that a geochemical model could be
constructed to include the effects of developing a reducing environment near the
repository base. This modeling should include adding flood waters into the repository
annually.
The 60% Design Report identified that dissolved oxygen concentrations in the
groundwater underlying the repository site are already fairly low (less than or equal to 1
milligram per liter). The report does not attempt to explain this condition and does not
explore the implications of this oxygen-reduced water rising into the repository during
annual flooding. With oxygen concentrations already low, the groundwater may more
likely become reduced as it rises into the repository during annual flooding. Reduced
geochemical conditions would then promote dissolving metal contaminants and increase
the possibility of contaminants migrating.
We concluded that EPA Region 10 and IDEQ have not sufficiently analyzed:
• the reduced geochemical conditions that are expected to form at the repository
base,
• the potential for annual inundation by floodwaters to introduce water into the
repository that will maintain the reduced conditions, and
• the possibility that dissolved contaminants will migrate away from the repository.
For example, staff calculating the quantity of water that might infiltrate have assumed
that inundation by flood waters will be on the order of 5 days, whereas the 60% Design
Report indicates annual flooding persisting for several weeks. Laboratory experiments
with contaminated soils have been limited to leaching with water similar to precipitation.
To understand if contaminants will be mobile under the reduced conditions expected to
form near the repository base, the experiments should include leaching experiments under
reduced conditions. Region 10 and IDEQ should conduct the analysis needed to
understand geochemical conditions that will prevail if the repository base stays saturated.
Factors to consider include infiltration of water with annual flooding and settlement
beneath the repository. If reduced conditions are predicted to be maintained near the
base, Region 10 and IDEQ should modify the repository design to mitigate any
unacceptable migration of dissolved contaminants that might result.
In response to OIG concerns, Region 10 and IDEQ prepared a draft scope of work for
this analysis. On December 2, 2008, we met with Region 10 and IDEQ to discuss the
scope of work and the need for their planned work and results to be reviewed. The
reviewer or reviewers should be independent of the design team and qualified to assess
that the analysis is technically sound and that the repository will protect human health
and the environment.
4 Reduced geochemical conditions form when the available oxygen has been consumed by biological or
abiotic processes.
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In its response to our report, dated April 17, 2009, Region 10 described the results of the
analysis. We acknowledge that the new work is extensive, especially the unsaturated
zone modeling.
Region 10 sent an additional response, dated May 15, 2009, that included a technical
review by an EPA research geochemist. The reviewer did not cover work related to
physical infiltration of water into the proposed repository.
We have identified several technical issues with the work the Region and IDEQ have
conducted that leave unresolved the amount of water that will be introduced into the
repository with flooding and rising groundwater levels. Region 10's response
memoranda are included in Appendix A. Our comments, describing technical issues that
need to be addressed, are in Appendix B.
Recommendation
We recommend that the EPA Regional Administrator, Region 10:
1. Finish analyzing the geochemical and physical conditions that might lead to
contaminants dissolving near the repository base; then confirm the adequacy of
the repository design to prevent dissolved contaminants from being released
under these conditions.
Agency Comment and OIG Evaluation
Region 10 concurred with the recommendation and prepared a technical analysis.
However, the Region's analysis included assumptions, with consequent conclusions, that
the OIG believes require technical verification. The Region should address these issues
in its 90-day response to the final report. The recommendation will remain open.
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Status of Recommendation and
Potential Monetary Benefits
POTENTIAL MONETARY
RECOMMENDATIONS BENEFITS (in SOOOs)
Claimed Agreed To
Amount Amount
Rec.
No.
1
Page
No.
9
Subject Status1
Finish analyzing the geochemical and physical 0
conditions that might lead to contaminants
dissolving near the repository base; then confrm
the adequacy of the repository design to prevent
dissolved contaminants from being released under
these conditions.
Action Official
Regional Administrator,
Region 10
Planned
Completion
Date
0 = recommendation is open with agreed-to corrective actions pending
C = recommendation is closed with all agreed-to actions completed
U = recommendation is undecided with resolution efforts in progress
10
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Appendix A
Agency Responses
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION 10
1200 Sixth Avenue, Suite 900
Seattle, WA 98101-3140
April 17, 2009
Reply To: Coeur d'Alene Field Office
MEMORANDUM
SUBJECT: OIG Draft Hotline Report - Contaminated Soil Waste Repository at East
Mission Flats, Idaho
OIG Assignment No. OCPL-FY08-0002
Dated March 30, 2009
FROM: Daniel D. Opalski, Director
Office of Environmental Cleanup
TO: Eric Lewis,
Product Line Director, Special Reviews
Office of Program Evaluation
This memorandum is in response to your draft hotline report on the Contaminated
Soil Waste Repository at East Mission Flats, Idaho. Region 10 would like to thank you
for your thorough review of the concerns raised by the complainant and the work
performed by EPA and the Idaho Department of Environmental Quality (IDEQ). We feel
the report fully endorses the extensive public outreach efforts that both agencies have
conducted for this repository site.
We also believe the report's technical recommendation is consistent with our
remedial design process and the adaptive management approach we are using for this
project and others throughout the Bunker Hill Superfund Site. Below you will find our
response to the draft recommendation, a discussion of other technical issues contained
within your report, and a recommendation from Region 10 on the content of your report.
Region 10 Response
Region 10 concurs with the report's recommendation and believes that the
analyses recommended by OIG have been completed by the IDEQ and incorporated into
the East Mission Flats Repository Draft 90% Design Report. As you are aware, the Draft
90% Design Report was not completed at the time the OIG interviews were conducted.
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The report is still in draft and is undergoing internal agency review. Once the agency
review is complete, IDEQ will provide the Final 90% Design Report to the public.
See OIG Comment 1 in Appendix B.
The Draft 90% Design Report contains two appendices that provide technical
support for the geotechnical and hydrogeologic aspects of the design. We are enclosing
copies of Appendix G and Q from the Draft 90% Design Report with this response.
Appendix G discusses consolidation of the soils within the footprint of the future
repository and Appendix Q addresses multiple geochemistry evaluations. In the interest
of brevity, the information contained in this memorandum are summaries of more
detailed information contained in appendices G and Q.
The following sections summarize the EPA and IDEQ response to the recommendation in
the OIG draft Hotline Report, our response to a request noted in the draft report, and a
suggested edit to the background section to provide more detail on the existing
environmental conditions at the site. Each issue is identified by the page and paragraph it
appears in the OIG report.
Recommendation, Page 9 Paragraph 2
Finish analyzing the geochemical and physical conditions that might lead
to contaminants dissolving near the repository base; then confirm the
adequacy of the repository design to prevent dissolved contaminants from
being released under these conditions.
Response: OIG staff reviewed design documents up to and including the 60%
Design Report. At the 60% design phase geochemical and physical conditions that might
influence contaminant mobility near the repository base had not been fully addressed.
Contaminant mobility is dependant on the presence of water within the repository to
saturate waste material and the geochemical behavior of metals in various geochemical
regimes. Both aspects of contaminant mobility were evaluated during the 90% Design
Report effort. The results of this evaluation are summarized in Appendix Q of the Draft
90% Design Report.
Three pathways of water influx to the repository were assessed for the 90%
Design Report: (1) downward vertical migration through the evapotranspiration (ET)
cover; (2) lateral infiltration due to contact with flood water; and (3) upward vertical
migration from the first water-bearing zone beneath the site. In addition to the water flux
modeling, an assessment of the potential for metals leaching from remedial action-
derived soil under oxidizing conditions was performed.
See OIG Comment 2 in Appendix B.
Results of the water influx assessment indicated infiltration through the top
surface of the repository will be minimized or eliminated by the construction of an ET
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cover. Vertical migration of groundwater upward into the base of the repository will not
occur due to the low hydraulic conductivity of the underlying soils and lack of sustained
driving hydraulic head. Long-term saturation of the base of the repository due to periodic
flood events and the development of reducing conditions are not expected. Lateral
infiltration model results estimate inundation by surface water due to periodic flooding
will saturate a ring approximately 13 to 16 feet wide and 0.3 to 0.5 feet thick at the
perimeter of the repository, less than 0.05% of the total repository volume. EPA and
IDEQ believe these are conservative estimates for the extent of saturation. The
assumptions used in the lateral infiltration model are listed in Appendix Q. Since
reducing conditions within the waste soil mass were not anticipated, an evaluation of
metals mobility under reducing conditions was not conducted.
See OIG Comment 3 in Appendix B.
Leachate generated from the small volume of water that may penetrate the yard
waste soil is not expected to contain elevated levels of metals. The surface water will be
saturated with oxygen, unlike the sub-oxic water in the first water-bearing zone. Based
on column tests approximating oxidizing conditions at the proposed repository, arsenic,
cadmium, and lead will not be mobilized and low levels of antimony and zinc will be
present. The column tests actually indicate that the existing deposits have the potential to
generate more metals than yard waste soil, specifically cadmium and zinc. Cadmium,
leached from the existing native deposits, may be in the range of the primary drinking
water maximum contaminant level (MCL), and zinc could exceed the secondary drinking
water MCL. Because the existing soils generate higher levels of metals than the
proposed yard waste, the reduction in infiltration beneath the repository footprint should
result in an overall decrease in metals leached to shallow groundwater and an
improvement in water quality.
See OIG Comment 4 in Appendix B.
The repository design is intended to protect human health and the environment
from releases due to reasonably foreseeable events and we believe it is adequate based on
the results of the referenced studies. Assessment of the design performance is part of the
operations and maintenance program established for the site. One goal of the design is to
protect groundwater quality. To help achieve that goal the groundwater monitoring
program will continue on a regular basis for as least as long as it takes to fill the
repository to capacity. Currently that monitoring program is conducted quarterly, but that
may be revised as appropriate through adaptive management and other means. In
addition, the site will be maintained in perpetuity by the State of Idaho to minimize the
potential for release of contaminants from the site to the environment. If the water
quality data show a trend of increasing dissolved metals concentrations, the first issue
would be to identify the cause of the increase. Once the cause of the increase is
identified, an appropriate remedy would be developed and implemented. This
management approach is based on realistic site characterization assumptions in an effort
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to produce a cost-effective solution to long-term waste soil storage at the East Mission
Flats Repository Site.
Third-Party Review Request, Page 9, Paragraph 1
. . . we met with Region 10 and IDEQ to discuss the scope of work and the
need for the planned work and results to be reviewed. The reviewer . . .
should be independent of the design team and qualified to assess that the
analysis is technically sound and that the repository will protect human
health and the environment.
Response: A review by an independent third party will be conducted in spring
2009. Comments from the third-party reviewer will be incorporated into the Final 90%
Design Report.
See OIG Comment 5 in Appendix B.
Suggested Edit to the Background section
The selected repository site at EMF is located within the drainage of the South
Fork and main stem Coeur D'Alene River. The entire river drainage has been impacted
by mine and smelter wastes, including the EMF site and surrounding area. In order to
provide a more complete description of the existing environmental conditions at the
repository site, the background section on Page 1 should include reference to the pre-
existing widespread distribution of metals in soils and groundwater.
See OIG Comment 6 in Appendix B.
Conclusion
I'd like to close by saying that Region 10 appreciates the work of your staff
during the review of the East Mission Flats Repository. We'd like to work with you to
finalize your report as soon as possible. At this time, EPA and IDEQ are planning to
finalize the repository design in May 2009. Please feel free to contact Bob Phillips if
you have any questions regarding this response.
Attachments (2)
cc: Michelle Pirzadeh,
Acting Regional Administrator, Region 10, ORA 140
Dan Opalski,
Director, Office of Environmental Cleanup, ECL 117
Cami Grandinetti
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Manager, Cleanup Unit 4, ECL 111
Angela Chung
Team Leader, Coeur d'Alene Basin, ECL 111
Ed Moreen
Project Manager, EPA - Coeur d'Alene Field Office
Bob Phillips
Audit Coordinator, OMP-145
Rob Hanson
Mine Waste Cleanup Program Manager, IDEQ, Boise
Andy Mork
Project Manager, IDEQ, Boise
See OIG Comment 7 in Appendix B.
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OFFICE OF
ENVIRONMENTAL CLEANUP
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION 10
1200 Sixth Avenue, Suite 900
Seattle, WA 98101-3140
May 15, 2009
MEMORANDUM
SUBJECT: Supplemental Information for March 30, 2009 Office of Inspector General
Draft Hotline Report - Contaminated Soil Waste Repository at East
Mission Flats, Idaho
Office of Inspector General Assignment Number: OCPL-FY08-0002
FROM: Daniel D. Opalski, Director
Office of Environmental Cleanup
TO: Eric Lewis, Product Line Director
Special Reviews
Office of Program Evaluation
This letter is in follow-up to my response dated April 13, 2009, in which I
indicated that a third party was going to review the geochemical analysis performed for
the contaminated soil waste repository at East Mission Flats, Idaho. That review has
been performed and a copy of the final memorandum is attached for your information.
With this review, all is in order for completion of the design and the inception of
the construction at this site. The Idaho Department of Environmental Quality plans to
begin construction as soon as possible and no later than the end of the month. We would
appreciate receiving your final report before that time.
Please feel free to contact Bob Phillips at (206) 553-6367 if you have any
questions regarding this letter.
Enclosure
cc: Ed Moreen, Project Manager
Environmental Protection Agency - Coeur d'Alene Field Office
Bob Phillips, Audit Coordinator
Environmental Protection Agency
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
NATIONAL RISK MANAGEMENT RESEARCH LABORATORY
GROUND WATER AND ECOSYSTEMS RESTORATION DIVISION
PO BOX 1198 • ADA, OK 74821
May 12, 2009
OFFICE OF
MEMORANDUM RESEARCH AND DEVELOPMENT
SUBJECT: Review of Appendix Q, East Mission Flats Repository Geochemistry
Evaluation, East Mission Flats Repository - Bunker Hill Site
(09-R10-001)
FROM: Richard Wilkin, Ph.D., Environmental Geochemist
Subsurface Remediation Branch
TO: Ed Moreen, Coeur d'Alene Field Office
U.S. EPA, Region 10
Per the request for technical assistance, this memo presents a technical review of
geochemical issues relating to contaminant behavior in the proposed East Mission Flats
(EMF) repository in Kootenai County, Idaho. In particular, this review focuses on the
potential for metals contained in waste materials to be leached, mobilized, and to
potentially degrade the quality of groundwater underlying the site.
The EMF repository site is located within the Coeur d'Alene River fioodplain.
The repository footprint is planned to be roughly triangular in shape, covering an area of
about 14 acres. The top of the repository will be limited to a maximum elevation of 2165
feet and is designed to rise approximately 32 feet above the existing ground surface. A
total of about 445,000 cubic yards of material (yard waste) will be placed in the EMF
repository. Wastes will be placed in 6- to 12-inch lifts and compacted to 90% in the
interior of the repository and 95% at the perimeter of the repository. It is noteworthy that
historical flood events have deposited metals-impacted silt and clay upon the entire site,
as the site is covered with a 1 to 4 foot-thick layer of soil that contains elevated
concentrations of lead, zinc, arsenic, and cadmium. Below this surface horizon, metals
concentrations drop sharply and reflect un-impacted native soils of the area.
Several groundwater monitoring wells have been constructed at the site. These
wells have been sampled on a quarterly basis since December 2007. The wells are
screened over a depth interval of 10 feet, from 17 to 27 feet below ground surface. Water
quality data and water level data have been collected from these wells. To date, results of
the monitoring indicate that groundwater underneath the site meets EPA drinking water
standards for the suite of metals tested. This is significant given the fact that
contaminated soils are present at the land surface.
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The potential for groundwater impacts from the placement of metals-impacted
soil at the EMF repository has been assessed by evaluating hydrological and geochemical
data and by conducting column leach tests to simulate site conditions. The leach tests
focused in particular on arsenic, lead, cadmium, copper, and zinc. Based on the results of
these tests, the EMF repository is not expected to impact metals concentrations in
groundwater beneath the site. The underlying soils have high sorptive capacity and are
predicted to remove any mobile metals from the aqueous phase. Because groundwater
impacts are unexpected, liners and leachate collection systems are not part of the design.
With respect to the hydrologic assessment, three different water entry pathways
were evaluated. These pathways include infiltration of precipitation and snowmelt,
migration of rising groundwater through the base of the repository, and lateral migration
along the perimeter of the repository from ponded surface water. Minimization of
infiltration will rely on surface grading and construction of a cover consisting of clean
soil and a planted native grass seed mix. Over the period of monitoring, groundwater
levels within the casing of the monitoring wells were found to rise to within about 0.5
feet of land surface. Estimates of water level changes suggest that the saturated zone will
not reach the base of the repository. Lateral ingress of water during seasonal high-water
events is expected to cause periodic saturation of a very small portion of waste materials
at the base of the repository. Less than 0.05% of the total repository volume is expected
to experience a moisture increase from lateral infiltration. Overall, lines of evidence
suggest that very little water will reach the waste materials and consequently there is an
expectation that limited opportunities will become available for geochemical processes to
take place that lead to leaching of metals from soil to the aqueous phase with subsequent
migration down to the groundwater table.
Geochemical evaluations involved evaluation of distribution coefficients,
sequential extraction procedures, synthetic precipitation leach tests, and column testing.
Site specific sorption coefficients were not determined. Average values for soil were
taken from the survey document published by EPA (2005). Note the Kd values published
in this report differ from those published in a more complete 3-volume review published
by EPA (1999a,b; 2004). The significance of this is in the fact that Kd values vary
widely and are most appropriately determined on a site-by-site basis. Nevertheless, the
main conclusion is reasonable that native materials at the EMF site are expected to have a
high sorption capacity for metals. The sequential extraction data collected on two
samples are especially important, as they provide some indication of the potential
mobility of metals under variable geochemical conditions. A significant fraction of the
arsenic, cadmium, copper, lead, and zinc in the soils are bound in the Fe/Mn oxide-bound
fraction (0.20 to 0.63). This fraction can potentially be leached under reducing
conditions. However, it is expected that oxidizing conditions will prevail throughout the
repository. The water that does infiltrate the repository is expected to be oxygenated
surface water, without the capacity to drive reductive dissolution.
The question as to whether the redox status of water will shift from oxidizing
conditions to more reducing conditions is not specifically evaluated with model or
laboratory assessments. The issue is of interest because, under iron-reducing conditions,
metals associated with Fe and Mn oxides/hydroxides could potentially be mobilized.
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Again, as noted above, the sequential extraction tests suggested a significant fraction of
metals associated in this bonding environment. It is important to point out that if
conditions moved beyond iron-reducing to sulfate-reducing (if sulfate-rich groundwater
migrated into the repository), metals would again be strongly partitioned to the solid
phase as insoluble metal sulfide clusters and precipitates. Hence there is a narrow
window of reduction-oxidation conditions that could develop in conjunction with seepage
of water through the repository mass and vadose zone to threaten the quality of the
underlying groundwater.
Development of a geochemical model to examine trends as the system moves
from oxidizing to reducing would require a significant amount of extra supporting
information (e.g., mineralogy, organic carbon concentrations and reactivity, etc.) and
would likely yield equivocal results. Likewise establishing lab experimentation to mimic
potential changes in reduction-oxidation conditions, would perhaps be more tractable, but
would present additional challenges and may ultimately miss conditions that end up
developing in the repository. Unfortunately, there is no well-established test that can be
performed to evaluate contaminant behavior over variable redox conditions. The primary
concern here, however, feeds back to whether or not water is expected to reach the waste
soils, from upward, downward, or lateral migration. The analysis presented in the
Repository Design documentation suggests that the repository soil mass will not be
saturated for prolonged periods of time. These conclusions are based upon a reasonable
set of data and model assumptions. Given these conclusions, concerns about the potential
for metals mobilization, while not to be discounted, do not warrant additional testing and
assessment. It is noted that a groundwater monitoring program is in place to track any
changes in groundwater quality through time. A phase of assessment and evaluation of
options would be triggered in the event that the monitoring program detected any
unanticipated changes in groundwater quality. It is recommended that the monitoring
program also track the moisture content in the repository in order to obtain data that can
be directly compared with estimates derived during the design phase of the project, and to
ensure that stored waste materials stay dry as intended in the repository design.
If you have any questions concerning these comments, please do not hesitate to
call me at your convenience (Wilkin: 580-436-8874). I look forward to future
interactions with you concerning this and other sites.
References
U.S. EPA (1999a). UNDERSTANDING VARIATION IN PARTITION COEFFICIENT, Kd, VALUES
Volume I: The Kd Model, Methods of Measurement, and Application of Chemical Reaction Codes. EPA
402-R-99-004, August 1999.
U.S. EPA (1999b). UNDERSTANDING VARIATION IN PARTITION COEFFICIENT, Kd, VALUES
Volume II: Review of Geochemistry and Available Kd Values for Cadmium, Cesium, Chromium, Lead,
Plutonium, Radon, Strontium, Thorium, Tritium (3H), and Uranium. EPA 402-R-99-004B, August 1999.
U.S. EPA (2004). UNDERSTANDING VARIATION IN PARTITION COEFFICIENT, Kd, VALUES
Volume III: Review of Geochemistry and Available Kd Values for Americium, Arsenic, Curium, Iodine,
Neptunium, Radium, and Technetium. EPA 402-R-04-002C, July 2004.
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U.S. EPA (2005). PARTITION COEFFICIENTS FOR METALS IN SURFACE WATER, SOIL, AND
WASTE. EPA/600/R-05/074, July 2005.
cc: Linda Fiedler (5203P)
Rene Fuentes, Region 10
Bernard Zavala, Region 10
John Barich, Region 10
Marcia Knadle, Region 10
Howard Orlean, Region 10
See OIG Comment 8 in Appendix B.
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Appendix B
OIG Comments
OIG Comment 1
The OIG has analyzed the new work that Region 10 and IDEQ have conducted and have
documented in the memorandum of April 17, 2009, and in the two appendices to the Draft 90%
Design Report (Appendices G and Q) that were attached to the memorandum. These
appendices to the Draft 90% Design Report are not included in Appendix A due to their length,
but are available upon request.
We acknowledge that the new work is extensive, especially the unsaturated zone modeling.
However, we have found technical issues in the analyses that prevent the work from meeting the
intent of the recommendation. Detailed information on these issues is outlined in other OIG
comments that follow.
OIG Comment 2
We agree with Region 10's assessment that water may enter the repository through three
potential pathways.
Region 10 notes that contaminant mobility is dependant on "the geochemical behavior of metals
in various geochemical regimes." However, the Region only investigated the potential for metal
leaching under oxidizing conditions. The Region should also conduct analyses of metals leaching
under anoxic conditions. Full saturation is not required for anoxic conditions to form. And yet the
Region uses its predictions that most of the repository will be unsaturated as reason for not
conducting analyses of metals leaching under anoxic conditions.
Region 10 states that mobility is "dependant on the presence of water within the repository to
saturate waste sediments." While we agree that the mobility of dissolved contaminants is
greatest when sediments are saturated, dissolved contaminants are mobile to some degree
under unsaturated conditions.
We do not believe that Region 10 has presented a decisive argument that groundwater and flood
waters will not enter the repository and dissolve the contaminants. As such, Region 10 needs to
investigate the possible mobilization of metals under anoxic conditions. (See also OIG
Comment 3.)
OIG Comment 3
Water Infiltration. We take issue with the analyses that form the basis for the Region's
conclusion that two pathways for water to infiltrate into the repository—rising groundwater through
the base of the repository and flood waters flowing laterally into the repository—will introduce
minimal water. These analyses were presented in the Region's memorandum and in the
Appendices to the Draft 90% Design Report (Appendices G and Q). We do agree with the
Region's assessment that the evapotranspiration (ET) cap that will cover the top and upper sides
of the repository will minimize the amount of precipitation (rain and snow melt) that enters through
the third possible pathway.
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Effects of Compaction on Groundwater Rise. The Region's analysis of the potential for
groundwater to rise into the repository used groundwater data from well MW-B. These data,
along with water level data from the other monitoring wells, were presented in Table 1 of
Appendix Q. A vertical seepage velocity consistent with the 8-foot rise in water levels observed
between February and June 2008 in well MW-B was calculated. However, when applying that
seepage velocity, the Region introduced the effects of settlement and compaction to predict
groundwater rise under the repository. The Region concluded that settlement and compaction
would reduce the predicted increase in the water level to the degree that no water would be
introduced into the repository from rising groundwater. We agree that compaction of the clay
materials underlying the repository would cause a decrease in hydraulic conductivity and,
therefore, could inhibit the rise in groundwater levels. However, we disagree that a 550 percent
decrease in hydraulic conductivity will occur under the entire repository.
Variable Settlement Under the Repository. Figure 11 in Appendix G presented graphically the
variable amount of settlement, and thus, the variable amount of decrease in hydraulic
conductivity, expected in the clay material underlying the repository. The analysis shows little
settlement expected under the outer parts of the repository. Therefore, in these areas, the
hydraulic conductivity will not be significantly decreased and water level rises of the magnitude
measured in 2008 in wells MW-B and MW-A should be expected to occur with that magnitude of
flooding. This rise in groundwater levels would introduce water into the base of the repository.
Clay Layer Under the Repository is Overestimated. We also disagree with the simplified
hydrogeologic characterization of the subsurface underlying the repository site that was used in
the analysis. As presented in Appendix G, 10 feet of clay is assumed to underlie the entire site.
The clay is assumed to be underlaid by 10 feet of gravely sand. This conceptual model is a
conservative approach for the geotechnical analysis focused on estimating the amount of
settlement that might occur under the repository. However, for estimating the hydraulic effects of
the subsurface materials on rising groundwater levels related to annual spring snow melt and
flooding, this conceptual model is anything but conservative. It overestimates the amount of clay
recorded in the site's geologic logs. Although every log shows some amount of clay, the
thickness of that clay varies greatly. At one location the clay is only 1.5 feet thick. The horizon
where the clay was logged varies as well. And some logs show more than one interval of clay.
This distribution of clay in the logs suggests that the clay is in lenses, as opposed to being in a
single continuous layer. Clay is the subsurface material that will undergo the greatest change in
its ability to transmit water due to the weight of the repository. The hydraulic transmission
properties of silt, sand, and gravel will not change appreciably. The Region's assumptions of a
thick and continuous clay layer bias the results of its analysis towards the sediments being overly
resistant to water level rises.
Compaction Increases the Hydraulic Gradient. Another issue we have with calculating
groundwater rise is with using the same hydraulic gradient resulting from the data collected in
well MW-B to calculate seepage velocity through materials compacted by the weight of the
repository. The overall energy driving the rise in the water level with flooding will be the same.
Therefore, as the hydraulic conductivity decreases with compaction, the upward vertical hydraulic
gradient across the sediments that drives the rise in the water level will increase. The hydraulic
gradient will not stay the same as the Region assumes in its calculations.
Analysis Needs to Assess Seepage Three-Dimensionally. The seepage velocity calculation
treats the rising water level measured in well MW-B as a one-dimensional problem. However, the
water level rises in the floodplain sediments in response to complex, dynamic, three-dimensional
interactions. New water and energy are added to the subsurface from recharge upgradient, local
areal recharge from snowmelt, linear recharge along the river, and areal recharge due to surface
water flooding out of the riverbanks and spreading across the flood plain. If the gravely sand
deposits being tapped by well MW-B are confined, as claimed in Appendix Q, then the upgradient
recharge would be the dominant, if not only, source of water coming in and would be responsible
for the rise in the water level. The seepage analysis needs to be three-dimensional. The level of
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water rises in well MW-B because of increases in pressures from upgradient, not from below as
implied in the one-dimensional analysis used in Appendix Q.
Limited Temporal Data Limits Understanding of the Dynamic System. The Region has little
temporal data to understand the dynamic groundwater system that is located so near the base of
the planned repository. Water levels now are being measured quarterly in six monitoring wells.
But the measurements extend only back to December 2007. In addition, when levels were high
and the site was flooded, measurements could not be obtained in some of the wells. This means
that there are even less data to understand the groundwater system when water levels are high.
Clay Compaction not Sufficient to Prevent Groundwater Rise. We know from measurements
made in June 2008 in wells MW-A and MW-B that water levels rose 7.5 to 8 feet from when
previously measured in February 2008. This same rise would have put the water level in wells
MW-C and MW-D about 1.5 feet above the ground surface. The actual water level could not be
measured in these wells due to flooding. Having the flooding and highest groundwater levels
occurring at the same time is consistent with the groundwater and surface waters systems being
hydraulically connected. This connection means that the energy of the flood waters as they
cascade out of the steep terrain of the upper river basin has the potential of being transmitted
through the groundwater system as well as the overbanked river system. The Region's analysis
relies on compaction of the clays underlying the repository to provide enough resistance to keep
the groundwater from rising into the repository. We remain unconvinced by the Region's
analyses that groundwater will not rise into the repository during some, if not all, floods.
Model Needs to Assess Floodwater Retained in Unsaturated Wastes. We conclude from the
Region's analysis of lateral infiltration during flooding that substantial floodwater remains in the
repository wastes months (90 days) after flooding has receded. The Region used a sophisticated
unsaturated model to estimate the third pathway for water entering the repository—infiltration
through the sides of the repository during flooded conditions. The Region presents results
(Figures 2 and 3 in Appendix C attached to Appendix Q of the draft 90% Design Report) at two
different times in the model run: after 75 days of flooding and then after 90 more days of
drainage. The Region also presents results from two versions of the model that assume different
hydraulic properties for the waste materials within the repository. In Appendix Q, the Region
focuses on the small area that is predicted to become fully saturated. However, the results show
that the saturation remains above 50 percent throughout the modeled domain. In other words, a
lot of water is in the unsaturated wastes. The amount of water retained is not presented,
although the model could be used for this calculation. The modeling results do not support an
assumption that the repository wastes will eventually dry.
Model Initial Conditions. Transient models, such as the one presented in Appendix Q, require
the modeler to assume conditions at the start of the simulation. The modeling results presented
show artifacts of the initial saturation condition assumed at the start of the modeled period
(Figures 2 and 3 in Appendix C attached to Appendix Q of the draft 90% Design Report). That
initial condition is described as 20 percent moisture content by volume. The modeling report
does not specify the porosity used in the model. But an effective porosity of 0.25 was used in
calculating the rising groundwater. If we assume a similar porosity was used in the unsaturated
zone modeling, this means the starting saturation would have been 80 percent. The results show
that the saturation remains above 50 percent throughout the modeled domain. The effects of the
initial conditions on the results should be investigated and minimized.
Model Did Not Assess All Relevant Flooding Scenarios. Only the 12-year-recurrence interval
flood was simulated in the modeling. Floods of greater frequency, such as the 1-year-recurrence
interval flood, and of greater magnitude, such as the 100-year-recurrence interval flood against
which the repository is being armored, also should be simulated to better understand the amount
of water that will enter the repository over the long run.
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Model Scenarios Did Not Assess Long-Term Repository Performance. The simulation
durations were very short: 75 days of flooding were followed by 90 days of drainage. The
simulation should have lasted at least 1 year to fully model the cyclical nature of the flooding at
the site. Carrying out a simulation over several flooding cycles would provide insight into the
long-term performance of the repository. A longer simulation over several flooding cycles would
help to minimize artifacts introduced by the assumed initial conditions.
Model Configuration Assumption. The assumption in the model that the base of the repository
is impermeable is conservative considering the short duration of the model simulations presented.
However, this assumption would affect model results if multiple flood cycles were simulated. Flux
out of the model domain through the seepage faces might be predicted because of the
assumption that the base is impermeable. This might result in the model predicting less retention
of water within the repository. In addition, flux to the groundwater can never occur with this model
assumption.
Model Should Be Used to Fully Assess and Document Repository Performance. In all of
these simulations, the amount of water entering and leaving the model domain and the change in
water stored within the domain should be documented. For the modeling that has been done, we
are presented only a few model results in graphical form. From these graphics, it appears that
substantial water is retained. However, the Region has not used the computational power of the
model to quantify the water flux and storage.
The Region needs to test model assumptions and fully analyze model results to ensure that the
current repository design, as presented in the Draft 90% Design Report, will minimize the
floodwaters entering and being retained in the repository wastes.
OIG Comment 4
We disagree with Region 10's conclusion that groundwater will not rise into the repository (see
OIG Comment 3). As the memorandum of April 17, 2009 states, the groundwater has low levels
of oxygen. We see the continued need for the Region to evaluate the geochemical potential for
metals within the repository to be mobilized under anoxic conditions.
OIG Comment 5
Region 10 should proceed with having the work technically reviewed, as the OIG analysis was
limited to information contained in the Region's response memorandum and the two draft
appendices. For example, the technical reviewer should have access to the full modeling
records. Technical review of the hydraulic analyses presented in Appendices G and Q of the
Draft 90% Design Report should specifically address the issues the OIG raised in these
comments.
OIG Comment 6
Information has been added to the final report describing the extent of contamination in the basin.
OIG Comment 7
Region 10 sent the OIG an additional response on May 18, 2009. The memorandum, dated May
15, 2009, included an independent review of Appendix Q to the 90% Design Report conducted by
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EPA's Office of Research and Development, dated May 12, 2009. These two memoranda are
included in Appendix A.
OIG Comment 8
Region 10, in its response of April 17, 2009, agreed to have its analysis reviewed by an
independent third party. We acknowledge that Dr. Wilkin, in his memorandum of May 12, 2009,
has thoroughly reviewed many of the geochemical issues related to contaminant behavior in the
proposed repository. However, Dr. Wilkin's review did not include hydrologic issues related to
contaminant mobility in the proposed repository. OIG Comment 3 presents a wide range of
hydrologic issues that we identified in the attachments to the April 17, 2009, response. As Dr.
Wilkin stated in his review, "the primary concern here, however, feeds back to whether or not
water is expected to reach the waste soils, from upward, downward, or lateral migration." The
Region's April 17, 2009, response included assumptions, with consequent conclusions, that OIG
believes require technical verification. The Region should address these issues in its 90-day
response to the final report. The recommendation will remain open.
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Appendix C
Distribution
Office of the Administrator
Acting Regional Administrator, Region 10
Agency Follow-up Official (the CFO)
Agency Follow-up Coordinator
Acting General Counsel
Director, Office of Environmental Cleanup, Region 10
Acting Associate Administrator for Congressional and Intergovernmental Relations
Acting Associate Administrator for Public Affairs
Audit Follow-up Coordinator, Region 10
Acting Inspector General
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