PB94-964083
EPA/ROD/R04-94/228
April 1995
EPA Superfimd
Record of Decision:
Savannah River Site (US DOE)
(O.U. 33), Aiken, SC
9/23/1994
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UNITED STATES DEPARTMENT OF ENERGY
SAVANNAH RIVER SITE
FINAL RECORD OF DECISION
REMEDIAL ALTERNATIVE SELECTION
FOR
Mixed Waste Management Facility (U)
Prepared by .
WESTINGHOUSE SAVANNAH RIVER COMPANY
SAVANNAH RIVER SITE
AIKEN, SC 29802
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PREPARED FOR THE US DEPARTMENT OF ENERGY UNDER
CONTRACT DE-AC09-89SR18035
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DECLARATION FOR THE FINAL RECORD OF DECISION
Site. Name and Location
Mixed Waste Management Facility (MWMF)
Savannah River Site
Aiken County, South Carolina
Appendix H of the Federal Facility Agreement (FFA) lists this unit as the Mixed
Waste Hazardous Waste Management Facility (Building Number 643-28G).
Statement of Basis and Purpose
This document presents the selected final preventive action for the MWMF Unit
at the Savannah River Site (SRS), which was developed in accordance with the
Comprehensive Environmental Response, Compensation and Liability Act of
1980 (CERCLA), as amended by the Superfund Amendments and
Reauthorization Act of 1986 (SARA), and to the extent practicable, the National
Oil and Hazardous Substances Pollution Contingency Plan (NCP). This
decision is based on the Administrative Record for this unit.
Description .0' the Selected Remedy
The selected final action remedy announced in this Record of Decision is no
further action. As described below, a remedy under RCRA was completed for
this unit in December 1990. This RCRA corrective action involved the
precompaction and placement of all contaminated materials under a low
permeability cap.
This RCRA remedy prevents physical exposure to
contaminants and mitigates further migration of contaminants to the
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groundwater by minimizing a liquid medium pathway (rainwater percolation) for
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transport.
No further action is necessary for the unit. . However, as a CQndition of the RCRA
Hazardous Waste Permit, post closure groundwater monitoring is required to
verify that no unacceptable exposures to potential hazards posed by conditions
. at the operable unit occur in the future.
This unit was closed by the
requirements of a closure plan approved in December 1987 by the state of
South Carolina under RCRA authority. The RCRA closure of MWMF began in
1988 and was completed in December 1990. MWMF was certified closed in
1991. In April 1991 , the closure certification was accepted by the state of South'
Carolina as being in compliance with RCRA requirements.
The major components of the RCRA preventive action included:
1) Precompaction.
2) Initial backfill after compaction to level 5 feet below final cover elevations.
3) Placement of a final cover over the trenches. The cover consists of a three
foot minimum layer of compacted kaolin clay with a permeability of 1 x1 0-7
em/see or less, two feet of final cover and vegetative cover, cap drainage and
stormwater conveyance system (See below).
Trench
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4) The MWMF is being routinely inspected for a minimum of 30 years to verify
the integrity of the cover system, fences, signs, etc. Any necessary repairs to the
cap will be made as part of the maintenance program.
5) Access to the MWMF is restricted to authorized personnel with appropriate
training on applicable requirements. The survey plat and records associated
with deed restricted use of the MWMF have been filed with Aiken County, SC.
Declaration Statement
Previous action taken at the MWMF was under a RCRA Closure Plan, per
NRDC et al. v. Herrington, Civ. Action No. 1:85-2583-6 (D.S.C. May 26, 1988),
approved by the state of South Carolina and was protective of human health
and the environment. Therefore, no further remedial action is necessary under
CERCLA. To ensure continued protection of human health and the
environment, this remedial action will be reviewed every 5 years, consistent
with the requirements of the NCP.
Date Thomas F. Heenan
Assistant Manager for Environmental
Restoration and Solid Waste
U.S. Department of Energy
9-22 -
yfry
'
Date John H. Hankinson, Jr.
Regional Administrator,
U.S. Environmental Protection Agency
Region IV
III
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SUMMARY OF. FINAL ACTION
REMEDIAL ALTERNATIVE SELECTION
FOR
Mixed Waste Management Facility (U)
Prepared by
WESTINGHOUSE SAVANNAH RIVER COMPANY
SAVANNAH RIVER SITE
AIKEN, SC 29802
------------------------------------------------------------------------
PREPARED FOR THE US DEPARTMENT OF ENERGY UNDER
CONTRACT DE-AC09-89SR18035
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DECISION SUMMARY
TABLE OF CONTENTS
Section Paae
I. Site and Operable Unit Names. Locations. and 1
Descriptions
II. Operable Unit History and Compliance History 4
III. Highlights of Community Participation 6
IV. Scope and Role of Operable Unit within the Site 6
Strategy
V. Summary of Operable Unit Characteristics 7
VI. Summary of Operable Unit Risks 7
VII. Explanation of Significant Changes 8
Appendices
A.
B.
References for Development of ROD Format
Responsiveness Summary
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I.
Site and Operable Unit Names, Locations, and Descriptions
The Savannah River Site (SRS) occupies approximately 310 square miles
adjacent to the Savannah River, principally in Aiken and Barnwell Counties of
South Carolina (Figure 1). SRS is a secured facility with no permanent
residents. The site is approximately 25 miles southeast of Augusta. Georgia.
and 20 miles south of Aiken. South Carolina. The average population density
in the counties surrounding SRS ranges from 21-524 people per square mile
with the largest concentration in the Augusta. Georgia. metropolitan area.
Based on 1990 census data, the population within a 50-mile radius of SRS is
approximately 634,784.
SRS is. owned by the United States Department of Energy (DOE).
Westinghouse Savannah River Company (WSRC) is the managing and
operating contractor for DOE. SRS produces tritium, plutonium. and other
special nuclear materials for national defense. The site also provides nuclear
materials for the space program, and conducts medical. industrial, and research
efforts. The Mixed Waste Management Facility (MWMF) is a source specific
operable unit within the Burial Ground Complex Fundamental Study Area. The
MWMF consists of 118 slit trenches, 1 Engineered Low Level Trench (ELLT-1),
and a naval core barrel mound and is located in the center of SRS. between F
and H Areas (Figure 2).
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G91H011.01
Rgure 1 Location of the Savannah River Site (SRS)
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Mixed Waste Management Facility
MWMF
~/
;;-
g Ii
G9.'DOO4.49l
Figure 2
MWMF
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II.
Operable Unit History and Compliance History
Operable Unit History
The MWMF operated from 1969 until March 11, 1986. During that time, this
facility, which comprises approximately 58 acres, received low-level radioactive
waste materials produced at the SRS. Some of these materials are classified
as mixed waste containing both hazardous and radioactive components under
the Resource Conversation and Recovery Act (RCRA). These trenches were
closed by precompacting and placing a protective multi-layer cover system
(Figure 3) over them to reduce rainwater contact with trench bottoms.
ComplIance HIstory
. RCRA preventive actions at the MWMF were conducted pursuant to the
requirements of the Resource Conservation and Recovery Act (RCRA) per
NRDC et al. v. Herrington, Civ. Action NO.1 :85-2583-6 (D.S.C. May 26, 1988)
which is an order from the court in settlement of the lawsuit for closure of the
facility under RCRA. In 1985 a RCRA Closure Plan was submitted to SCDHEC.
The .closure plan underwent several revisions prior to approval by SCDHEC in
1987. Closure of the MWMF was begun in 1988 and completed in December
1990. The MWMF was certified closed in 1991. In April 1991, the closure
certification was accepted by SCDHEC as being in compliance with RCRA
requirements. A RCRA Part B Permit Application for Post-Closure Care was
submitted in November 1992.
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Mixed Waste Management Facility
Closure Cap Cross Section.
Vegetative Cover
Top Soil (2 ft)
Compacted Low Permeability
Clay Layer (3 ft)
Subgrade
(Initial Fill) (2-7 ft)
. Backfill (To Grade)
Trench
G~160H~.01
Figure 3
MWMF Cap Cross Section
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Closure activities specifically included precompaction; construction of a low
permeability cap over the trenches; and restoration of the area.
RCRA preventive activities at the MWMF became subject to CERCLA when the
entire SRS facility was placed on the National Priorities Ust (NPL) in December
1989. The MWMF is a source-specific operable unit within the Burial Ground
Complex Fundamental Study Area.
. III.
Highlights 01 Community Participation
The public comment period ran from 01 August 94 - 30 August 94. All
comments submitted on the Proposed Plan have been incorporated into this
ROD, where appropriate and are addressed in the Responsiveness Summary
(Appendix B).
IV.
Scope and Role 01 Operable Unit within the Site Strategy
The selected RCRA remedy involved the placement of all contaminated
materials under a low permeability cap. The remedy prevents physical
exposure to contaminants and mitigates further migration of contaminants from
the MWMF to groundwater by minimizing a liquid medium pathway (rainwater
. percolation) for transport.
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V.
Summary of Operable Unit Characteristics
Waste from SRS disposed In the form of job control waste such as rags, gloves
and coveralls, soli, construction debris, failed equipment, spent air filters, spent
lithium-aluminum targets, irradiated scrap metal, naval reactor hardware, lead
shielding. waste oil, scintillation fluids, cadmium and silver coated beryl
saddles. were sent to the MWMF. The constituents of concern at the MWMF are
barium, chloroform, cadmium, 1,1-dichloroethane, vinyl chloride, trans-1,2
dichloroethylene. phenol, aluminum, iron, manganese, carbon-14, lead, tritium,
nickel, tetrachloroethylene, trichloroethylene (TCE), zinc, uranium-234/235,
. .
uranium-238. The primary constituents of concern are tritium, lead, TCE, and
uranium.
VI.
Summary of Operable Unit Risks
Due to the previous MWMF RCRA preventive action, No Further Action under
CERCLA is necessary for this source control operable unit. The RCRA
preventive action is protective to human health and the environment and
satisfies CERCLA requirements.
The trenches were first compacted and then were covered with a low
permeability soli cap. Therefore. exposure through surface soil and sediment
pathways is minimized because of this RCRA cap.
Preventive alternatives were developed for the MWMF based on effective
technologies available at the time the RCRA Closure Plan was prepared. The
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RCRA Closure Plan was initially submitted to SCDHEC in November 1985 and
was approved. following several revisions, in December 1987.
Options regarding the MWMF evaluated at that time included:
Alternative 1
No Action
- Alternative 2
No Waste Removal, Waste Consolidation, and Closure
.. .Alternatlve 3
. W~te Removal and t,;losure
Alternative 2 was selected within the RCRA closure process in. 1985 as the most
technically effective of the three alternatives for protection of human health and
the environment. Closure of the MWMF was begun in 1988 and completed in
1990. The closure was certified in April 1991 and accepted by SCDHEC as
being in compliance with RCRA and state requirements. The closure is
considered a final action under CERCLA.
VII.
Explanation of Significant Changes
There were no significant changes made to the remedy decision since the
publishing of the proposed plan on 01 August 1994.
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Appendix A
References for Development of ROD Format
EPA, 1991. -Guide to Developing Superfund No Action, Interim Action, and
Contingency Remedy RODs,- OSWER Publication 9355.3-02FS-3, U.S.
Environmental Protection Agency, Washington, D.C., April 1991.
WSRC, 1992. -Draft RCRA Facility Investigation/Remedial Investigation
Program Plan,- WSRC-RP-89-994, Rev. 1, Chapter 15, Westinghouse
Savannah River Company, Aiken, South Carolina, May 1992..
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Appendix B
Responsiveness Summary
DOE has received comments regarding the MWMF and they have been
addressed in this Responsiveness Summary. These comments are available
for review in the Administrative Record.
A member of the public provided comments on the MWMF item in the S R S
Environmental Bulletin volume 5 number 15 dated July 25, 1994,. This
comment referred to adding a figure representing the amounts of ha,zardpus
waste in the facility and the approximate volume of compacted waste. The
issue raised in the SRS Environmental Bulletin concerning the hazardous
waste volumes has been addressed and is clearly presented in the Proposed
Plan. The issue concerning the volume of compacted waste is clarified here.
Compaction at this waste site was done in order to form a stable foundation for
the kaolin clay cap; therefore, no measurement was conducted to determine the
exact waste consolidation.
An interested party provided comments on th~ MWMF Proposed Plan in a letter
to C. V. Anderson dated September 8, 1994. The specific comments and their
responses are as follows:
C:
SRS has not demonstrated the assertion that because of the RCRA
closure at the MWMF "the unit poses no cu"ent or potential threat to human
health or the .environment- and, thus, -no further action is necessary under
CERCLA. - In ERPs July 9, 1993 letter to David Wilson at SCDHEC and Len
Sjostrom at SRS we provided extensive comment and criticism on the RCRA
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post-closure risk assessment for the MWMF. We have never received a direct
response from SRS. If there is a risk assessment to support a "no further
remedial action" position under CERCLA then we request the opportunity to
review it.
R:
RCRA closure of a I~nd disposal unit in which waste is left in place is .
protective of human health and the environment under RCRA and therefore, a
risk assessment' is not required. . The actions taken at the MWMF under the
. .
RCRAICERCLA program were completed within the requirements set forth by
SCDHEC and the EPA.
c:
Additionally, the decision to leave waste buried at MWMF and the other
Burial Ground Complex facilities is a de facto decision about long-term land
use. Given the long-lived nature of many of the wastes, the implied restriction
goes far beyond the 30 and 100 year institutional control projections which
shaped the earlier risk assessments. If, in fact, unrestricted use of the site after
100 years is not going to be safe, then SRS and its regulators should
acknowledge this and commit to some additional decision making.
R:
These actions are protective of human health and the environment and
will be reviewed every 5 years as required by CERCLA and the RCRA post
closure care permit renewal process.
c:
Until there is a meaningful land-use planning process at SRS involving
stakeholders, the attainment of primary drinking water standards at the
perimeter of the BGC should be a minimum requirement. It's not clear that
SRS can meet these standards without additional source control at MWMF and
the other BGC facilities. If additional source control is necessary to meet
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primary drinking water standards at the BGC perimeter, SRS and its regulators
should work together to examine how to locate specific sources 0' contaminants
within the BGe a."1d what technology and/or research and development options
are necessary to remedy the situations.
R:
The MWMF groundwater is being addressed under RCRA which is a
groundwater based program. Under RCRA, monitoring 01 the subsurface
contamination is being. conducted.
Investigation 01 the groundwater
contamination is currently ongoing and will be addressed under separate
regulatory documentation. This MWMF Proposed Plan is for the source control
. .
operable unit only. All other source control units, including the groundwater
operable unit, will be addressed under separate Proposed Plans and Records
of Decision.
DOE land use policy is being developed currently but until
finalized, 5 and 30 year reviews will be maintained.
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