PB97-964031
EPA/541/R-97/204
February 1998
EPA Superfund
Record of Decision:
Savannah River Site (USDOE) OU 17
L-Area Oil and Chemical Basin (904-83G)
and L-Area Acid Caustic Basin (904-79G)
Aiken, SC
9/30/1997
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RECORD OF DECISION
REMEDIAL ALTERNATIVE SELECTION (U)
L-Area Oil and Chemical Basin (904-83G) and L-Area Acid Caustic Basin (904-79G)
WSRC-RP-97-I43
Revision. 1 July 1997
Savannah River Site
Aiken, South Carolina
Prepared by:
Westinghouse Savannah River Company
for the
U. S. Department of Energy Under Contract DE-AC09-96SR18500
Savannah River Operations Office
Aiken, South Carolina
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Rccurd oflX-cision for the LAOCI1/1.AACB (904-83G and 904-79G) (U) WSRC-RP-97-143
Savannah Kivcr Silc Revision. I
July 1997 Declaration
DECLARATION FOR THE RECORD OF DECISION
Unit Name and Location
L-Area Oil & Chemical Basin (904-83G) and L-Area Acid/Caustic Basin (904-79G)
Savannah River Site
Aiken, South Carolina
The L-Area Oil & Chemical Basin (LAOCB) and L-Area Acid/Caustic Basin (LAACB) source Operable
Unit (OU) is listed as a Resource Conservation and Recovery Act (RCRA) 3004(u) Solid Waste
Management Unit/Comprehensive Environmental Response, Compensation and Liability Act (CERCLA)
unit in Appendix C of the Federal Facility Agreement (FFA) for the Savannah River Site (SR'S).
Statement of Basis and Purpose
This decision document presents the selected remedial alternative for the LAOCB/LAACB located at the
SRS south of Aiken, South Carolina. The selected alternative was developed in accordance with
CERCLA, as amended, RCRA, and to the extent practicable, the National Oil and Hazardous Substances
Pollution Contingency Plan (NCP). This decision is based on the Administrative Record File for this
specific RCRA/CERCLA unit
w
Assessment of the Site
Actual or threatened releases of hazardous substances from this site, if not addressed by implementing the
response action selected in this Record of Decision (ROD), may present an imminent and substantial
endangerment to public health, welfare, or the environment
Description of the Selected Remedy
The preferred alternatives for the LAOCB source OU are Alternative P-3: In-situ Stabilization and
Disposal in the LAOCB for remediating the LAOCB pipeline, and Alternative S-4: In-situ Stabilization
and Capping of the LAOCB for remediating the LAOCB soil. These alternatives will meet remedial action
objectives by eliminating the potential Digestion of soils and produce grown in soils, and reduce/minimize
direct radiation exposure and potential future impacts to groundwater. The capped area will be maintained
and Institutional Controls will remain in place as long as the waste remains a threat to human health or the
environment.
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Record of Decision for ihc LAOCB/l.AACB (904-83G and 904-79G) (U) WSRC-RI'-97-M-!
Savannah River Sue Revision I
July 1997 Declaration
The preferred alternative for the LAACB is No Action. The LAACB will be backfilled with native soil and
vegetation will be established in a similar fashion to the clean closure of the F-, H-, K-, and P-Acid/Caustic
Basins (WSRC, 1995a).
Groundwater south of L Reactor has been impacted by several source OUs including the LAOCB. The
groundwater has been identified as a separate OU, as discussed in Section IV of this ROD, and will be
addressed in a separate groundwater ROD.
Implementation of the preferred alternatives will require both near- and long-term actions which will be
protective of human health and the environment. For the near-term, signs will be posted at the LAOCB
which indicate that this area was used for the disposal of radioactive and hazardous substances. In
addition, existing SRS access controls will be used to maintain the use of this site for industrial activities
only. Near-term actions at the LAACB will consist of backfilling and seeding to establish vegetation and
posting to indicate that this area was used for the disposal of hazardous substances.
In the long-term, if the property is ever transferred to non-Federal ownership, the U.S. Government will
create a deed for the new property owner which would contain information in compliance with Section
120(h) of CERCLA. The deed would include a notification disclosing former waste management and
disposal activities as well as remedial actions taken on the site, and any continuing groundwater monitoring
commitments. The deed notification would, in perpetuity, notify any potential purchaser that the property
has been used for the management and disposal of radioactive and hazardous substances.
The deed would also include deed restrictions precluding residential use of the property. However, the
need for these restrictions may be reevaluated in the event that contamination no longer poses an
unacceptable risk under residential use. In addition, if the site is ever transferred to non-Federal ownership,
a survey plat of the area will be prepared, certified by a professional land surveyor, and recorded with the
appropriate Barn we 11 County recording agency (the LAOCB/LAACB OU is located in northern Barnwell
County).
The post-ROD document, the Corrective Measures/Remedial Design Work Plan (CM/RD WP), will be
submitted to the U.S. Environmental Protection Agency (EPA) and the South Carolina Department of
Health and Environmental Control (SCDHEC) within approximately one month after the issuance of the
ROD. The CM/RD WP will contain a summary description of the scope of work for the remedial action
design, implementation/submittal schedule for subsequent post-ROD documents, and an anticipated field
activities start date. The regulatory review period, SRS revision period, and final regulatory review and
approval period will be 45 days, 30 days, and 30 days, respectively.
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Record of Decision for the LAOC8/I.AACB (904-8 3G and W4-79O) OJ) WSRC-RP-97-U:,
s.nannah River Site Revision I
July 1997 Decla/anon
The SCDHEC has modified the SRS RCRA permit to incorporate the selected remedy.
Statutory Determination
Based on the LAOCB/LAACB RCRA Facility Investigation/Remedial Investigation (RFI/RI) Report and
the Baseline Risk Assessment (BRA), the LAOCB source OU poses significant risk to human health and
the environment. Therefore, a determination has been made that in-situ solidification/stabilization (S/S) of
the pipeline, excavation and placement of pipeline in the LAOCB, and in-situ S/S and capping of the
LAOCB is protective of human health and environment for the contamination remaining in the LAOCB
pipeline and LAOCB soil. In-situ S/S and capping will result in the protection of unit groundwater through
the stabilization of unit constituents of concern (COCs), and will be protective of on-unit human and
ecological receptors by shielding radiation exposure and preventing the assimilation of unit COCs. The
selected remedy is protective of human health and the environment, complies with Federal and State of
South Carolina requirements that are legally applicable or relevant and appropriate to the remedial action,
and is cost-effective. This remedy utilizes permanent solutions and alternative treatment (or resource
recovery) technology to the maximum extent practicable, and satisfies the statutory preference for remedies
that employ treatment that reduces toxicity, mobility, or volume as a principal element.
Based on the LAOCB/LAACB RFI/RI Report and the BRA, the LAACB source OU poses no significant
risk to human health and the environment. Therefore, a determination has been made that a No Action
alternative is appropriate for the LAACB. The No Action alternative will be protective of human health
and the environment.
Section 300.430 (f)(4)(ii) of the NCP requires that a five year review of the ROD be performed if
hazardous substances, pollutants, or contaminants remain in the waste unit. The SRS RCRA permit is
reviewed every five years, and was most recently renewed on September 5, 1995. Because this remedy
will result in hazardous substances remaining on-site above health-based levels, the three Parties [U.S.
Department of Energy (DOE), SCDHEC, and EPA] have determined that a Five Year Review of the ROD
for the LAOCB/LAACB will be performed to ensure continued protection of human health and the
environment
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Record of Decision for Uie LAOCB/LAACB (904-83G and 904-79G) (U)
Savannah River Site
July 1997
WSRC-RP-97-143
Revision I
Declaration
Date
Date
Date
Thomas F. Heenan
Assistant Manager for Environmental Quality
,U. S._ Department of EnvEY, Savannah River Operations Office
Richard D. Green
Acting Division Director
Waste Management Division
U. S. Environmental Protection Agency - Region [V
R. Lewis Shaw
Deputy Commissioner
Environmental Quality Control
South Carolina Department of Health and Environmental Control
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DECISION SUMMARY
REMEDIAL ALTERNATIVE SELECTION (U)
L-Area Oil and Chemical Basin (904-83G) and L-Area Acid Caustic Basin (904-79G)
WSRC-RP-97-I43
Revision. I
July 1997
Savannah River Site
Aiken, South Carolina
Prepared by:
Westinghouse Savannah River Company
for the
U. S. Department of Energy Under Contract DE-AC09-%SR 18500
Savannah River Operations Office
Aiken, South Carolina
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Record of Decision for the I.A(XT)/I.AACn (904-8XJ and 904-79G) (U) WSRC-RP-97-M3
.S;ivnnriah River Site Revision. I
Jul> 1997 Page iiiolM
DECISION SUMMARY
TABLE OF CONTENTS
Section Page
I. Savannah River Site and Operable Unit Name, Location, Description, and Process
History... _ I
II. Site and Operable Unit Compliance History 7
III. Highlights of Community Participation 10
IV. Scope and Role of the Operable Unit Within the Site Strategy 11
V. Operable Unit Characteristics 22
VI. Summary of Operable Unit Risks 35
VII. Remedial Action Objectives and Description of Considered Alternatives for-the
LAOCB/LAACB Source Control Operable Unit !.. '. 48
VIII. Summary of Comparative Analysis of the Alternatives...". 58
IX. The Selected Remedy 77
X. Statutory Determinations 80
XI. Explanation of Significant Changes 81
XII. Responsiveness Summary 81
XIII. Post-ROD Document Schedule 81
XIV. References „ 85
List of Figures
Figure I. Location of the Savannah River Site and Major SRS Facilities 2
Figure 2. Topographic Map of the LAOCB/LAACB and Surrounding Area 3
Figure 3. Unit Layout and RFI/RI Sampling Locations of the LAOCB/LAACB 5
Figure 4. Aerial Photograph of LAOCB 6
Figure 5. Unit Layout and RFI/RI Sampling Locations of the LAACB Pipeline 8
Figure 6. RCRA/CERCLA Logic and Documentation 12
Figure 7. Response Action Selection Process 18
Figure 8. Steel Creek Watershed and Associated Operable Units 21
Figure 9. Conceptual Site Model forme LAOCB 23
Figure 10. Conceptual Site Model for the LAACB 24
Figure 11. Gross Alpha and Non-Volatile Beta Concentrations vs. Depth 28
Figure 12. Cross-Section of LAOCB and Surrounding Soils 30
Figure 13. Post-ROD Document Schedule 82
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Record of Decision for the LAOCB/LAACB (904-83G and 9CM-79G) (U) WSRC-RC-97-M3
Saxannah River Site Revision I
July 1997 Paac ivol'vi
List of Tables
Table 1. Summary of Detected Constituents - LAOCB Soil and Sediment 27
Table 2. Current and Future On-Unit Risks - LAACB 37
Table 3. Current and Future On-Unit Risks - LAOCB 40
Table 4. Operable Unit COCs and Risk Based RGs 46
Table 5. Comparative Analysis of Soil/Sediment Alternatives - LAOCB 59
Table 6. Comparative Analysis of Pipeline Alternatives - LAOCB 65
Appendix
A. Responsiveness Summary 87
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Record of Decision for the LAOCB/LAACB (904-83G and 904-79G)
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Record of Decision for the LAOCB/tAACB (904-83G and 904-79G)(U) WSRC-RP-97-M3
Savannah River Site Revision I
July 1997 Page vi .if v,
LIST OF ACRONYMS AND ABBREVIATIONS (continued)
SCHWMR South Carolina Hazardous Waste Management Regulations
SDCF soil/debris consolidation facility
SRS Savannah River Site
SVOC semi volatile organic compound
TBC To Be Considered
TCLP Toxicity Characteristic Leaching Procedure
UMTRCA Uranium Mill Tailings Radiation Control Act
USC unit specific constituent
VOC volatile organic compounds
WSRC Westinghouse Savannah River Company
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Savannah River Site
CITIZENS ADVISORY BOARD
Recommendation No. 37
May 13,1997
L-AREA OIL & CHEMICAL BASIN AND L-AREA ACID/CAUSTIC BASIN
Background
The L-Area Oil & Chemical Basin and L-Area Acid/Caustic Basin are within 400 feet of L-Area.
They were used as unlined earthen basins for disposal of liquid waste. The L-Area Oil & Chemical
Basin (LAOCB) was used from 1961 to 1979 and the L-Area Acid/Caustic Basin (LAACB) was used
from 1955 to 1968. Both are located in an area of SRS designated for Industrial Use by the CAB1 and
other Stakeholders . The stakeholders recommended and the DOE-SR plans on DOE maintaining
control of all of SRS indefinitely1-2. The LAOCB. covers about 0.5 acre, is 12 feet deep and the con-
tamination is confined to approximately the top 2 feet of the soil in the basin bottom. Although some
volatile organics and tritiated water probably moved deeper, complete characterization of ground wa-
ter contamination has not been done.
Analysis of the risks indicate concern for a future hypothetical onsite resident or onsite industrial
worker in the immediate vicinity of the LAOCB only3. These risks are associated largely with direct
radiation from Co-60 and Cs-1373. However, there are also risks via ingestion and inhalation path-
ways. The LAOCB pipelines (about 1000 ft) contain radioactive materials which could reach the soil
after the pipe disintegrates3. Because the pipeline is buried under four feet of soil, there is no risk to
the occasional visitor. There are no risks associated with the LAACB.
The preferred alternative3 is a good engineering solution for remedial action. It includes in-situ
stabilization, backfilling and capping for the LAOCB, in-situ stabilization of the radionuclides in the
pipe, and removal of the pipe and its disposal in the LAOCB. Total costs (not including expenditures
for reports and regulatory approval) are estimated at $4.6 million for the preferred alternative. The
risk analysis indicates that no remedial action is needed for the LAACB .
Recommendation
• The preferred alternative negotiated by DOE, EPA, and DHEC be implemented.3
This alternative includes in-situ grout stabilization, backfill and capping and may reduce
the future remediation costs for the groundwater.
I. CAB Recommendations 1. Industrial/Residential Land Use Guidelines for CERCLA Near Term Decision-nuking, and 8.. Nine Part Recommendation
on (he future uses of the Savannah River Site.
2. Savannah River Siie Future Use Project Report - Stakeholder Recommendations for SRS Land Facilities, published by the U.S Department of linorjy
Savannah River Operations Office. January 1996.
3. Statement of Roils/Proposed Plan for the L-Arca Oil & Chemical Basin and L-Arca Acid/Caustic Basin. February 1997.
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Savannah River Site
CITIZENS ADVISORY BOARD
Minority Report
Submitted Regarding
Recommendation No. 37
May 13, 1997
Two recommendation alternatives were presented to the foil Board on May 13, 1997, regarding
remedial activities at the L-Area Oil & Chemical Basin. Three Board members were in favor of the
following alternative:
*--
Because there is no significant risk under the current L-Area industrial operations, because there is
some risk to workers implementing the preferred clean up action, because the area is designated as.
industrial1'2, because DOE-SR intends to maintain control of the SRS for the ir. definite future1"2,
because the dominant radiological hazard is associated with radionuclides with half lives of 30 years
or less, because ground water remediation is to be considered later for the whole L-Area, and because
the SRS budget continues to decline, the SRS Citizens Advisory Board recommends that
• The LAOCB be only backfilled with clean dirt at this time. This will provide direct radiation
shielding and eliminate possible inhalation and ingestion of contamination by humans. It will
also significantly reduce exposure of wildlife to contaminated soil. Costs should be less than
the $ 1.4 million estimated for backfilling and capping.
• Money saved by implementing this recommended action instead of the preferred action should
be used to mitigate risks at higher risk sites.
• Deed restrictions be placed on the land records now to avoid potential conflicts during possible
future land disposal action by the Federal Government.
• Gro'-indwater remediation be considered as part of the general L-Area groundwater
assessment. If necessary, the LAOCB should be capped with a low permeability barrier later.
Board members in favor of this alternative stated they were concerned that although the L-Area Oil &
Chemical Basin is listed as the second highest risk in the Federal Facility Agreement which addresses
the Environmental Restoration Program, the basin is not the second highest risk at SRS. Comments
were that in light of budget reductions, funding for this activity may be more appropriately allocated
to other SRS programs which pore higher risks.
1. CAB Recommendations 2. Industrial/Residential Land Use Guidelines for CERCLA Near Term Decision-making, and 8, Nine Pan Recommendation
on the future uses or the Savannah River Site.
2. Savannah R ver Site Fuiure Use Project Report - Stakeholder Recommendations for SRS Land Facilities, published by the U.S. Department oi Energy
Savannah River Operations Office, January 1996.
3 Statement of Basis/Proposed Plan for the L-Area Oil & Chemical Basin and L-Arca Acid/Caustic Basin. February 1997.
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Record of Decision lor Ihc I.AtX'H.'t.AACB <II 1
I. SAVANNAH RIVER SITE AND OPERABLE UNIT NAME, LOCATION, DESCRIPTION,
AND PROCESS HISTORY
Savannah River Site Location, Description, and Process History
The Savannah River Site (SRS) occupies approximately 310 square miles of land adjacent to the Savannah
River, principally in Aiken and Bam we 11 counties of western South Carolina. SRS is a secured U.S.
Government facility with no permanent residents, and is located approximately 25 miles southeast of
Augusta, Georgia and 20 miles south of Aiken, South Carolina (Figure 1).
SRS is owned by the U.S. Department of Energy (DOE). Management and operating services are currently
provided by Westinghouse Savannah River Company (WSRC). SRS has historically produced tritium,
plutonium, and other special nuclear materials for national defense and the space program. Chemical and
radioactive wastes are by-products of nuclear material production processes.
Operable Unit Name, Location, Description, and Process History
The Federal Facility Agreement (FFA) for the SRS lists the L-Area Oil and Chemical Basin/Acid Caustic
Basin (LAOCB/LAACB), 904-83G and 904-79G, as a Resource Conservation and Recovery Act/
Comprehensive Environmental Response, Compensation and Liability Act (RCRA/CERCLA) unit
requiring further evaluation, using an investigation/assessment process that integrates and combines the
RCRA Facility Investigation (RFI) process with the CERCLA Remedial Investigation (Rl) to determine the
actual or potential impact to human health and the environment The LAOCB and LAACB are located
south of L Area in an area of low to moderate relief (Figure 2). They are situated on the southern flank of a
hill approximately 300 feet (ft) south of the L-Area perimeter fence and 1,250 ft north of L Lake. The area
lies at an elevation of approximately 235 ft above mean sea level (msl), and 45 ft above the elevation of L
Lake. Surface water runoff in L Area drains southward to L Lake via overland flow and small intermittent
stream channels and drainage ditches.
Direct precipitation (rain, snow, ice, etc.) is currently the only source for basin water. The LAOCB and
LAACB both act as intermittent, wet-weather ponds. The LAOCB contains water at most times while the
LAACB is more frequently dry. Overflow from the LAOCB would drain southward to L Lake as
described above. Overflow is not probable because the capacity of the basin is approximately four times
the volume of water attributable to annual precipitation. Wastewater has never been reported to have
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Kccord <>lDecision lor the I.AOCH/l.AACB (904-83G and 904-79GHU)
S.ivumuh River Sue
July 1997
WSRC-RP-97-M3
Revision I
Case 2 ol"92
Figure I. Location of the Savannah River Site and Major SRS Facilities
TRUE
SITE «""
NQHTH
NOT TO SCALE
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Record of Decision for (he LAOCIJ/I.AACH <90J-X_1
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Kc>.> I1'1'" I'.i'jc 4 i2
overflowed from the LAOCB. The LAACB was designed to discharge basin water through an overflow
pipe located at the southern end of the basin. A discharge ditch was also constructed to receive water from
the overflow pipe. The overflow pipe is positioned to operate only at very high water levels to prevent
overtopping the basin berm.
LAOCB
The LAOCB was designed and constructed as an unlined seepage basin in 1961 for the purpose of
disposing of small volumes of wastes that were not appropriate for discharge to local streams, regular
seepage basins, or the 200-Area waste management system. The LAOCB measures 182 ft long by 108 ft
wide at the berm with an overall area of 0.45 acres and an average depth of 12 ft. The LAOCB received
waste via a bermed concrete drainage pad that was located outside the basin perimeter fence, and from a
gravity flow underground pipeline (6-inch diameter steel) originating at the maintenance..Hot Shop (Figure
3). The pipeline from the Hot Shop was originally constructed to extend to the L-Area Reactor Seepage
Basin for an approximate total length of 750 ft. The pipeline was installed prior to the excavation of the
LAOCB. When the LAOCB was constructed, all pipeline drainage was diverted to the LAOCB. The
approximately 275 ft of pipeline between the LAOCB and the Reactor Seepage Basin was plugged off at
each end and taken out of use. This section of the pipeline is not part of the LAOCB/LAACB OU and will
be addressed as part of the L-Reactor Seepage Basin (see Section IV). In addition, a second pipeline (2-
inch diameter steel), located just south of the main pipeline, extends approximately 450 ft from the Hot
Shop to the LAOCB.
w
The exact quantity of wastewater discharged to the basin is not documented and the following summary on
chemical composition of discharges is based on process knowledge. Liquid wastes consisting of small
volumes of slightly radioactive oil and chemical wastewater were sent to the LAOCB from throughout
SRS, but came primarily from the reactor areas. Wastes were transported to the drainage pad in tank
trucks, metal drums, skid tanks, and other containers. The Hot Shop (Building 717-G) discharged
decontamination wastewater containing radionuclides, detergents, and spent degreasing solvents through
the pipeline to the basin. Historical records indicate that wastes from all sources contributed approximately
2.2 curies (Ci) of alpha emitters and 270 Ci of nonvolatile beta emitters including O.I Ci of strontium-90
(wSr) and 0.4 Ci of cesium-137 (l37Cs) (Fenimore et al., 1988).
The basin remained active until 1979 when all discharge to the basin ceased, and has remained open from .
1979 to present. The LAOCB is currently surrounded by a chain link fence, posted as a radiological
contamination area, and contains low-lying vegetation indigenous to the area that has grown back since
removal in 1993 (Figure 4).
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Keeord of Decision lor I he L.-V K'lU.AACH (904-83G and WM-79G) (U).
Stiv:nm;ih HIMJI Silc
Julv |
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Record ofDccision lor ihc LAOCB/I.AACB (904-83G and 904-79G) (U) WSRC-RP-97-143
Suvjimah River Silc Revision I
July 1997 I'agc 7
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Record of Decision for ihc l.AOCB/LAACD (904-83G and 904-79G) (U)
Sjvamiali River .Sue
Julv 1997
WSRC-RP-97-143
Revision I
Page g of92
Figure 5. Unit Layout and RFI/RI Sampling Locations of the LAACB Pipeline
PHASE IWVB
SMC1MC LOCATIOre
FOR
L-AKA ACD/C/USTIC BASK
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Kccnrd of Decision lor the LAOCU/I.AACB (904-83G and 904-79G) (U) WSKC-RP-97-143
Suvann.ih River Site Revision I
July 1997 ' I'a!ie9of92
SRS Compliance History
Waste materials handled at SRS are regulated and managed under RCRA, a comprehensive law requiring
responsible management of hazardous waste. Certain SRS activities have required Federal operating or
post-closure permits under RCRA. SRS received a hazardous waste permit from the South Carolina
Department of Health and Environmental Control (SCDHEC); the permit was most recently renewed on
September 5, 1995. Pan IV of the permit mandates that SRS establish and implement an RFI Program to
fulfill the requirements specified in Section 3004(u) of the Federal permit.
On December 21, 1989, SRS was included on the National Priorities List (NPL). This inclusion created a
need to integrate the established RFI Program with CERCLA requirements to provide for a focused
environmental program. In accordance with Section 120 of CERCLA, DOE has negotiated a Federal
Facility Agreement (FFA) (WSRC, 1993a) with the U.S. Environmental Protection Agency (EPA) and
SCDHEC to coordinate remedial activities at SRS into one comprehensive strategy which fulfills these dual
regulatory requirements.
Operable Unit Compliance History
LAOCB
As previously stated, the LAOCB is listed in the FFA as a RCRA/CERCLA unit requiring further
evaluation to determine the actual or potential impact to human health and the environment. An RFI/RJ
characterization and Baseline Risk Assessment (BRA) were conducted for the unit between 1993 and 1995.
The results of the RFI/RI and BRA were presented in the RFI/RI and BRA reports. The RF1/RI and BRA
reports were submitted in accordance with the FFA and the approved implementation schedule, and were
approved by the EPA and SCDHEC in February 1996. The Corrective Measures Study/Feasibility Study
(CMS/FS) and Statement of Basis/Proposed Plan (SB/PP) were submitted in accordance with the FFA and
the approved implementation schedule, and were approved by EPA and SCDHEC in March 1997.
LAACB
As previously stated, the LAACB is listed in the FFA as a RCRA/CERCLA unit requiring further
evaluation to determine the actual or potential impact to human health and the environment An RFI/RI
field characterization was conducted and documented for the LAACB at the same time as the LAOCB.
The RFI/RJ and BRA reports were submitted in accordance with the FFA and regulatory approved
implementation schedule, and were approved by the EPA and SCDHEC in February 1996. The CMS/FS
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Record of Decision lor the I.AOCB/I.AACB (904-83G and 904-79G) (U) \VSRC-RI'-97-U3
.S;iv;inn.-ih River Nile ' KCMMOII I
July IW Page I0of>2
and SB/PP were submitted in accordance with the FFA and the approved implementation schedule, and
were approved by EPA and SCDHEC in March 1997.
III. HIGHLIGHTS OF COMMUNITY PARTICIPATION
Both RCRA and CERCLA require the public be given an opportunity to review and comment on the draft
permit modification and proposed remedial alternative. Public participation requirements are listed in
South Carolina Hazardous Waste Management Regulation (SCHWMR) R.61-79.124 and Sections 113 and
117 of CERCLA. These requirements include establishment of an Administrative Record File that
documents the investigation and selection of the remedial alternatives for addressing the LAOCB/LAACB
soils and groundwater. The Administrative Record File must be established at or near the facility at issue.
The SRS Public Involvement Plan (DOE, 1994) is designed to facilitate public involvementih the decision-
making process for permitting, closure, and the selection of remedial alternatives. The SRS Public
Involvement Plan addresses the requirements of RCRA, CERCLA, and the National Environmental Policy
Act, 1969 (NEPA). SCHWMR R.61-79.124 and Section 117(a) of CERCLA, as amended, require the
advertisement of the draft permit modification and notice of any proposed remedial action and provide the
public an opportunity to participate in the selection of the remedial action. The Statement of
Basis/Proposed Plan for the L-Area Oil and Chemical Basin and L-Area Acid/Caustic Basin (WSRC,
1997a), a part of the Administrative Record File, highlights key aspects of the investigation and identifies
the'preferred action for addressing the LAOCB/LAACB.
The FFA Administrative Record File, which contains the information pertaining to the selection of the
response action, is available at the EPA office and at the following locations:
(J. S. Department of Energy
Public Reading Room
Gregg-Graniteville Library
University of South Carolina-Aiken
171 University Parkway
Aiken, South Carolina 29801
(803)641-3465
Thomas Cooper Library
Government Documents Department
University of South Carolina
Columbia, South Carolina 29208
(803) 777-4866
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KC...MJ HI IKviM.'ii lor UK- l..\(«. Ill V\< H r>cM-X.;<, and <«M-?'« i) <(') U SK< -KI'-''~-l 1:
Vi\ann.ih Ki\cr ^ilc I\OI^»'»M !
JllK l.-m I'.IMJ; i | ,,|
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Record ol'Decision liir ihc I.AOCH/LAACU (904-83G and 904-79G) (U)
S.H .Illllllll |il\CI SllC
July 1997
WSRC-RP-97-M3
' Revision i
I'aac 12 ol 92
Figure 6. RCRA/CERCLA Logic and Documentation
SRS RCRA/CERCLA UNIT
PRELIMINARY EVALUATION
• Unit Reconnaisance
• Unit Screening
Rf I/RI WORK PLAN
Develop Conceptual Site Model (CSM)
Identify Data Needs
Develop Data Quality Objectives and
Decision Logic
Detailed Sampling and Analysis Plan
UNIT/SITE CHARACTERIZATION
• Implement RFI/RI
• Data Evaluation vs. DQO's
• Re-Evaluate CSM
Additional
Characterization
Characterization
Complete?
Characterization
Complete?
DATA EVALUATION
Validation
Verification
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KccurJ of Decision Cor llic LAOCR/LAACU (904-83G and 904-79G) (U)
S.ivaiui:ili River Silc
July IW
WSRC-RP-97-IJj
RL'VISJO/I I
Pace 13 at 92
Figure 6.
(continued) RCRA/CERCLA Logic and Documentation
Treatability Studies
(as necessary)
NO ACTION REMEDY
RFI/RJ REPORT
Establish Remedial Action
Objectives
CMS/FS Report
Identify Response Actions
Identify Technologies
Alternatives Development
Alternatives Screening
Detailed Analysis
SB/PP
• Preferred Alternative
• Draft Permit Modification
• Public Comment
RECORD OF DECISION
• Select Remedy
• Responsiveness Summary
• Final Permit Modification
CORRECTIVE MEASURE/
REMEDIAL ACTION
• Unit Closure
• Post Closure Documentation
(Post Construction Report)
Baseline Risk Assessment
• Determine Unit Risk
• Develop RGs
POST ROD
DOCUMENTATION
• Remedial Design
Workplan/Report
• Remedial Action
Workplan/Report
-------
Kin-id ill IX:i.iMt'ii l»r Ihc I A< H. IM \.\l H I'/ni-.X :t i .nut •ni;.--i(,)l| i U xlti -K I'••'"•! I ;
s.i\ .Lmt.ih U :\ cr Mlc K<-\ i-n-n I
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- _
groundwater. and surface water) comprising the x^aste site and surroundinu areas; the evaluation of risk to
human health and the local ecological community the screening of possible remedial actions to identify the
selected technology which will protect human health and the environment: implementation of the selected
alternative; documentation that the remediation has been performed competently; and evaluation of the
effectiveness of the technology. The steps of this process are iterative in nature, and include decision
points which involve concurrence between the DOE (as owner/manager), the EPA and SCDHEC (as
regulatory oversight), and the public. The RCRA/CERCLA process as applied to the LAOCB/LAACB is
outlined below.
RFI/RI Work Plan
Based on the data reviewed and collected during the unit preliminary screening and process knowledge, a
conceptual site model (CSM) was developed to: determine the source, primary contaminated media.
migration pathways, exposure pathways, and potential human and ecological receptors Section V
provides the unit-specific CSM for the LAOCB/LAACB OU, and a summary of the characteristics of the
primary and secondary sources and release mechanisms for the units as determined in the RFI/RI.
Development of the CSM facilitates the initial step of determining the nature and extent of unit
contamination through the identification of data gaps using the Data Quality Objectives (DOO) process.
DQOs are useful in identifying data needs associated with the sources and exposure media and in
developing a sampling and analytical plan which describes the procedures for collecting sufficient data of
known and defensible quality. The unit disposal and monitoring history indicated that the
LAOCB/LAACB and associated pipelines are a probable contamination source that may represent
unacceptable risk to human health and the environment. Multiple data needs were identified to reduce the
uncertainty associated with the contamination of the LAOCB/LAACB to include the nature and extent of
contamination in: (I) basin vegetation, surface water, and soils, (2) soils adjacent to the basins, (3) soils
along the pipelines, and (4) groundwater in the vicinity of the basins. Consequently, to make key remedial
decisions it was necessary to develop a work plan to satisfy these data needs to determine the associated
risk to human and ecological receptors. The approved RFI/RI work plan for the LAOCB/LAACB (WSRC,
1993) outlined the specific characterization activities that were necessary to meet the DQOs for the
LAOCB/LAACB.
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Kcc.uJ of Decision for Ihc LAOCIUI.AACB (904-83G and 904-79G) (II) WSRC-RP-97-I-G
S;tv;iMn:ih River Siic Revision. I
Jul> I'M? Pasc 15 of 92
Unit/Site Characterization (RFI/RI)
The primary need for the RFI/RJ is to establish unit-specific constituents (USCs) that pose potential risk
through various exposure routes and determine their distribution in source media associated with the unit.
One of the principle requirements for determining USCs is to establish unit-specific background
concentrations. Once established, the maximum values of detected constituents at the unit are screened
against two-times mean background concentrations to identify constituents that exceed background. These
data are used to further define the Constituents of Potential Concern (COPCs) and Constituents of Concern
(COCs) during the risk assessment. In addition, these data provide the contaminant profile and mass which
is necessary to determine potential contaminant migration to off-unit receptors.
The data needs for the LAOCB/LAACB RFI/RI were satisfied through the following characterization
activities:
• sampling/analysis of basin surface water/sediment and subsurface soil (secondary source)
• sampling/analysis of basin perimeter surface/subsurface soil (secondary source)
• sampling/analysis of subsurface soil along pipelines (secondary source)
• sampling/analysis of basin vegetation (exposure pathway)
• sampling/analysis of groundwater (exposure pathway)
• -air monitoring during sampling activities (exposure pathway)
t.
• sampling/analysis of background vegetation, soil, and groundwater
• radiation survey of the ends of the LAOCB pipelines (secondary source)
Streamlined investigation activities and the development of innovative sampling devices to minimize
worker exposure during the collection of radioactive environmental media were utilized during the RFI/RI
for the LAOCB/LAACB. Blanks and duplicate samples were collected during the RFI/RI at defined
frequencies and analyzed by independent, certified laboratories to provide defensible data. The results of
the RFI/RI of the LAOCB/LAACB are reported and discussed in Section V.
Baseline Risk Assessment
The intent of the BRA is to develop risk information necessary to assist in the decision-making process for
remedial sites. Risk from die unit/site is quantified, based on unit specific data, for current and future
human and ecological receptors through multiple exposure routes as identified in the CSM. Carcinogenic
risk at or above 1.0 x 10-6 (one excess human cancer in a population of one million) are considered
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Record of Decision for Ihc LAOCH/I.AACO (904-K3G and VO-J-79O) (U) WSRC-RI'-'»7-|4J
Snvannah Rivtr Site " Revision I
July 1997 |>;,pC u, of*)^
significant. In addition, if a hazard index (HI) is greater than 1.0 for noncarcinogenic constituents, there is
concern that adverse health effects may occur.
The overall objectives of the BRA conducted for the LAOCB/LAACB were met as summarized below:
• identified the unit-specific COPCs (primarily radionuclides) and quantified the risk they pose to
applicable human and ecological receptors (unacceptable risk to human health);
• determined that the LAACB does not pose a significant risk to human receptors;
• determined that the LAOCB poses an unacceptable risk to human receptors;
• determined that the LAOCB and LAACB do not pose unacceptable risk to ecological receptors;
• determined that the LAOCB and LAACB and the surrounding areas do not provide habitat for any
threatened, endangered, or sensitive plant or animal species that may be impacted by unitfontaminants;
• established human health COCs for the LAOCB (primarily radionuclides) that pose unacceptable risk
and determined the remedial goal (RG) concentrations of chemical and radiological constituents that
can remain in-situ and will be adequately protective of human health and the environment;
• established the data necessary to compare potential human health and environmental impacts of
remedial actions applicable to the LAOCB and other radioactive seepage basins at SRS to include
stabilization/solidification, vitrification, and removal.
A summary of the results of the BRA for the LAOCB/LAACB are presented in Section VI.
CMS/FS
The results of the RFI/RI and BRA provide the basis for establishing unit-specific remedial action
objectives in the CMS/FS. Remedial action objectives for the LAOCB (including its pipelines) were
developed to address: unit-specific contaminants, media of concern, potential exposure pathways, and RGs.
The remedial action objectives are based on the nature and extent of contamination, threatened resources,
human and environmental risk information, and the potential for human and environmental exposure. In
addition, the preliminary remediation goals for the LAOCB and its pipelines were developed based upon
Applicable or Relevant and Appropriate Requirements (ARARs) or other information from the RFI/RI
Report and the BRA.
The methodologies used to identify and screen relevant technologies for the remediation of the waste unit
followed an established process developed by the EPA. The goal of this remedy selection process is to
select corrective measures/remedial actions that are protective of human health and the environment, that
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Record ol Decision lor the I.AOCH/I.AACB (904-83G and 904-79G)(U) WSKC-RP-97-143
Savannah River Sue Revision I
July 1997 . I'agc 17 of 92
maintain protection over time, and that minimize contaminant (or waste) mobility, toxicity, or volume
through treatment, when possible [CERCLA 300.430 (a)( I)(!)]. The selection of a response action for the
waste unit proceeded in a series of steps as defined in the NCP of November 20, 1985 (50 FR 47973) and
outlined in Figure 7. In addition, the remedial alternatives were further evaluated for the LAOCB
(including its pipelines) by following nine selection criteria established by the NCP:
• Overall Protection of Human Health and the Environment
• Compliance with Applicable or Relevant and Appropriate Requirements
• Long-Term Effectiveness and Permanence
• Reduction of Toxicity, Mobility, or Volume Through Treatment
• Short-Term Effectiveness
• Implementability
• Cost
• State Acceptance
• Community Acceptance
The results of the CMS/FS conducted for the LAOCB/LAACB are summarized in Section VII, and a
summary of the comparative analysis of the alternatives is provided in Section VIII.
SB/PP
The culmination of the response action selection process is the Statement of Basis/Proposed Plan (SB/PP).
The purpose of the SB/PP is to facilitate public participation in the remedy selection process through the
solicitation of public review and comment on all the remedial alternatives described. The SB/PP presents
the lead agency's preliminary recommendation (s) concerning how best to undertake a remedial action at a
particular waste unit. The SB/PP describes all remedial options that were considered in detail in the
CMS/FS, and explicitly identifies the preferred alternative for a remedial action at a waste unit and the
preference rationale.
The SB/PP directs the public to the RFI/RJ, BRA, and CMS/FS reports as the primary sources of detailed,
site specific information, and information on the remedial alternatives analyzed, and provides information
on how the public can be involved in the remedy selection process. The public is notified of a public
comment period through mailing of the SRS Environmental Bulletin, the Aiken Standard, the Allendale
Citizen Leader, the Bamwell People Sentinel, The State, and Augusta Chronicle newspapers, and through
announcements on local radio stations. In addition, DOE platforms a public meeting during the public
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Record ol Decision lor (he I.AOCB.1.AACB (904-83G and 90-4-79O) (U)
S;iv.innah Kivcr Silc
Julv 1997
WSRC-RP-97-M3
Revision I
Pace IS of 92
Figure 7. Response Action Selection Process
ltap«t Prertou. Scoping SMpr.
-Omm'«i
Establish Remedial Action.Objectives
Develop General Response
Actions Describing Areas or
Volumes of Media to Which
Containment, Treatment, or
Removal Actions May Be Applied
Identify Potential
Treatment and
Disposal Technologies
and Screen Based on
Technical Implementability
Evaluate Process Options Based
on Effectiveness, Implementability,
and Relative Cost, to Select a
Representative Process for each
Technology Type
Source: EPA. 1988
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Record of Decision for the l.ACX'H/l.AACR (904-83G and 904-79G) (U) WSRC-RP-97-N3
S:iv:inn:th River Site . Revision I
July 1997 l'ageiyol'92
comment period to receive and discuss questions and comments from the public on the preferred remedial
alternative.
ROD
The ROD documents the remedial action plan for a unit and consists of three basic components: a
Declaration, the Decision Summary, and the Responsiveness Summary. The purpose of the Declaration is
to certify that the remedy selection process was carried out in accordance with the requirements of
CERCLA and, to the extent practicable, the NCR. The Decision Summary is a technical and information
document that provides the public with a consolidated source of information about the history,
characteristics, and risks posed by a unit, followed by a summary/evaluation of the cleanup alternatives
considered that led to the selected remedy. The Responsiveness Summary presents comments received
during the public comment period (April 4 through May 18, 1997) on the SB/PP, and a response to each
comment or criticism, submitted in writing or orally. The Responsiveness Summary for the
LAOCB/LAACB is provided in Appendix A and an explanation of significant changes resulting from
public comment is provided in Section XI.
SRS received a hazardous waste permit from the South Carolina Department of Health and Environmental
Control (SCDHEC) which is renewed every five (5) years. The permit was most recently renewed on
September 5, 1995. Part IV of the permit mandates that SRS establish and implement an RFI Program to
fulfill the requirements specified in Section 3004(u) of the Federal permit. The LAOCB and LAACB are
Solid Waste Management Units (SWMUs) listed on the SRS RCRA Permit because the units received
hazardous substances. Thus, the remedial decision for these SWMUs requires a RCRA Permit
Modification. Specific comments and responses received during the April 4, 1997 - May 18, 1997 public
comment period on the proposed remedial action and the associated draft RCRA permit modification are
included in the Responsiveness Summary of this ROD (Appendix A) and with the final RCRA Permit The
final RCRA Permit and the ROD document the final decision for this operable unit
Post-ROD Documentation
The post-ROD documentation consists primarily of the design documents that are required prior to
initiating a remedial action. Specific post-ROD documents include, the corrective measure/remedial design
workplan, the corrective measure/remedial design report, the corrective measure/remedial action workplan,
and the post-construction report A discussion of the schedules that apply to these documents is provided
in the SB/PP and Section XIII of this ROD.
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Record of Decision for ihc LAOCH/LAACB (904-83G and 904-79O) (U) WSRC-RP-97-M3
Savannah River Silo Revision I
July 1997 Pa'jc 20 ol 9:
Southern L-Area Remedial Strategy
The RFI/RI process provides a method of managing the steps to ultimate remediation of a specific waste
unit. It is often preferable to group waste unit components and actions to expedite characterization and
remediation of the components that pose the most significant risks. These groupings are typically
designated as OUs. A "source control OU" may consist of a number of potential sources of contamination,
and usually indicates that there is a preference toward collective characterization and ultimate remediation
of these sources. A "groundwater OU" usually consists of a specific area of groundwater contamination
and proposed actions related to its characterization and ultimate remediation, and/or the timing of these
actions.
The LAOCB and LAACB have been grouped into a source control OU that is located within the Steel
Creek Watershed (Figure 8). Several source control and groundwater OUs within this watershed will be"
evaluated to determine future impacts, if any, to associated streams and wetlands. It is the intent of SRS,
EPA, and the SCDHEC to manage these sources of contamination to minimize impact to the watershed.
To effectively manage the impact to the Steel Creek Watershed (groundwater, streams, and wetlands), a
comprehensive characterization and regulatory process plan for the waste units in the vicinity of the
LAOCB/LAACB OU was developed. This characterization and regulatory process plan provides a
programmatic method of promoting continuous characterization, risk assessment, remedial assessment, and
remedial action.
The waste units included in the remedial process plan consist of the LAOCB/LAACB OU, the L-Area Hot
Shop, and the L-Reactor Seepage Basin. The LAOCB and L-Area Hot Shop received mixed radioactive
and hazardous waste, the L-Reactor Seepage Basin received radioactive waste, and the LAACB received
characteristic hazardous waste. Because the waste units are located in close proximity and have known and
probable groundwater contamination, they represent a complex characterization, remediation and
regulatory challenge. The plan consists of a phased approach for the characterization, documentation, and
remediation of these waste units. The location of these waste units and overall components of the
comprehensive plan are described in Appendix A of the RFI/RI Report (WSRC, 1996a).
During the characterization process of the LAOCB/LAACB OU, it was recognized that the highest
concentrations of contaminants and the contaminants with the highest potential risk were primarily
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oI'Di-uMoii li)i ilic I.AOCB/I.AACH (WM-KjG nnd 9()-4-7l>G) (U)
WSRC-KI'-97-|.»j
Rcvisiiin I
I'aae 21 of 92
Figure 8. Steel Creek Watershed and Associated Operable Units
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kin'iil ){,) il.) \\ SKi'-KI'--';-! I ;
Vi\.nm.ih KIM.T Nile KL-VIMKII I
/iil\ I1*)- \'.i»>: 12 .it O.J
restricted to surficial soils, subsurface soils, and surface water within the LAOCB. In addition, it was
recognized that the LAOCB represents a significant source of contamination to unit groundwater. The
characterization of the LAOCB/LAACB OU and its associated RFI/RI and BRA documentation provide
sufficient information to move forward with a remedial action of this source control OU. Therefore, the
CMS/FS, SB/PP, and this ROD are focused on this source control OU.
Groundwater contamination associated with the LAOCB was found to consist primarily of tritium and
solvents. However, it was recognized that the extent of the groundwater contamination had not been
completely characterized during the RFI/RI. In addition, groundwater contamination is also likely
associated with the L-Area Hot Shop and the L-Area Reactor Seepage Basin. Groundwater contamination
associated with the Hot Shop is not documented, but soil gas data suggest that chlorinated organic solvents
have been released to the soil in the area and may have impacted the local groundwater. Groundwater
contamination associated with the L-Area Reactor Seepage Basin is known to consist of tritium (historical
groundwater monitoring).
A comprehensive groundwater OU was created as the L-Area Southern Groundwater OU because of the
uncertainty associated with the nature and extent of the known and suspected groundwater plumes in the
vicinity of the LAOCB/LAACB OU, L-Area Hot Shop, and L-Area Reactor Seepage Basin. Because any
remedial actions directed toward the groundwater could cause further commingling of contaminant plumes,
a phased remedial investigation of the groundwater plumes will be conducted as pan of the integrator OU
strategy. The phased process would continue until all the components of the source control, vadbse zone,
and groundwater OUs are characterized and documented.
V. OPERABLE UNIT CHARACTERISTICS
CSMs were developed for the LAOCB and LAACB that identify the primary sources, primary
contaminated media, migration pathways, exposure pathways, and potential receptors for each unit. The
CSMs for the LAOCB and LAACB are presented in.Figures 9 and 10, respectively, and are based on the
data that are presented in the RCRA/CERCLA documentation for these units. The Data Summary Report
(WSRC, I995b), RFI/RI Report (WSRC, I996a), and Baseline Risk Assessment (WSRC, I996b) contain
detailed analytical data for all of the environmental media samples taken in the characterization of the
LAOCB/LAACB. These documents are available in the Administrative Record (See Section HI).
As previously stated in Section IV, it has been recognized that the highest potential risk is primarily
restricted to soil and surface water within the LAOCB. In addition, the extent of the groundwater
-------
PRIMARY
PRIMARY RELEASE
SOUHCK MECHANISM
Rad
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LE&ENJI
• = Principal Pathways for quantitative evaluation
O = Pathways for qualiiaiive evaluation
— = Incompleie pnihways
^~
—
—
Record of Decision for the LAOCB/LAACB (904-83G and 904-79G) (U) ^"^iTi
Sjs.innah River Silo . Pace 23 of 92
J,,lv IQ07 .
-------
I'HIMAItV
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. si:
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Record of Decision lor ihc I.AOCB/LAACB (904-83G and 904-79G)(U) WSRC-RP-97-I43
S.ivnimuJi River Nile Revision. I
July IS>97 Page 25 of 92
contamination has not been completely characterized during the RFI/RI, and further investigation is
necessary to proceed with a risk assessment and CMS/FS for unit groundwater. Therefore, the following
discussion of the OU will be focused on the primary and secondary sources of the LAOCB and LAACB,
and will not include a description of the characteristics of the unit groundwater.
L-Area Oil & Chemical Basin
LAOCB Primary Sources and Release Mechanisms
The primary sources were radioactive wastewater discharged to the LAOCB from the Hot Shop via the
LAOCB pipelines and other SRS areas via the concrete drainage pad (see Figure 9). Residual wastewater
is no longer present in the LAOCB, and its presence in the pipelines is unlikely because all piping was
constructed as gravity feed, and no wastewater has been discharged through the piping for approximately
30 years. Radioactive contamination on the internal surfaces of the LAOCB pipelines is documented
[approximately 300,000 disintegrations per minute (dpm) as measured at the discharge end in the
LAOCB], and there is a high probability of radioactive contamination of the concrete drainage pad and
associated piping based on process knowledge.
The primary release mechanisms are deposition inside the basin, deposition outside the basin from
overflow, deposition onto the pipeline and drainage pad surfaces, and leakage of the pipelines (see Figure
9). The most significant of these release mechanisms are the release of unit contaminants to the surface
soil in the basin bottom and pipeline leaks to the subsurface soils along the LAOCB pipelines. In addition,
there are no documented occurrences of basin overflow, and surface radiation surveys indicate the basin
did not overflow.
LAOCB Secondary Sources and Release Mechanisms
Secondary sources include sludge/organic sediment and subsurface soil in the LAOCB, surface water in the
basin that accumulates from precipitation, surface and subsurface soil around the basin, concrete and steel
pipe, and subsurface soil along the pipeline (see Figure 9). A detailed sampling and analysis plan was
prepared and implemented to investigate these secondary sources and a complete description of the
sampling methods and protocols are provided in the RFI/RI Report (WSRC, 1996a).
Sludge/organic sediment and subsurface soil were collected from five locations within the LAOCB (see
Figure 3) using a remote vibracore sampling device to reduce cross contamination of samples and
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Record of Decision for (lie L/MXTU/LAACIl (904-83G and :»
minimize worker exposure. The sampling of the basin sludge indicates that the sludge is approximately six
inches thick. Based on the analysis of samples collected from the five locations within the basin, the
sludge and organic sediment within the LAOCB is highly contaminated with radionuclides. Twenty-four
radionuclides and gross alpha and non-volatile beta were detected above screening levels in the LAOCB
sludge (Table I). The major man-made radionuclides with respect to activity within the basin sludge are:
americium-241 ("'Am), l37Cs, cobalt-60 <*°Co), curium-244 (244Cm), europium-152 (l32Eu), IS4Eu, '55Eu,
promethium-147 (""Pm), 238Pu, 239Pu, "'Sr, uranium-234 (234U), 135U, 238U, and 3H. A review of the data
also indicates the primary fission products are l>7Cs, '"Sr, '52Eu, IMEu, and IS5Eu, the primary activation
product is 60Co, and the primary alpha-emitters are 238Pu, 239Pu, and 2j8U. In addition, the data indicate
that tritium contributes at least one third of total activity within the basin sludge with a maximum of 15,498
pCi/g. The subsurface soil underlying the basin sludge is also highly contaminated with radionuclides as
described for the sludge. The average activity for the basin sludge and subsoils (to a depth of, 1.5 ft) is
3833.3 pCi/g for the major radionuclides (i.e., 24lAm, l37Cs, "to, l52Eu, l54Eu, li5Eu, "8Pu, 239Pu, ^Sr,
235U, 238U, and 3H). Based on the activities of the soil samples collected during this investigation, the total
radionuclide activity within the basin (including the sludge and subsoils to a depth of 1.5 ft) is estimated at
approximately 4.2 Ci.
The concentrations of radionuclides in the LAOCB subsoils tend to decrease rapidly with depth. An
analysis of the attenuation of the maximum gross alpha and non-volatile beta activities indicates that
radionuclide concentrations (other than 3H) should reach background activity levels within approximately
two feet from the top of the sludge. Linear regression of the gross alpha values (log) versus sample depth
demonstrates that the maximum observed gross alpha values will decrease to activities less than detectable
levels at a depth of approximately 1.5 ft from the top of the sludge (Figure 11). Linear regression of the
gross non-volatile beta values (log) versus sample depth demonstrates that the maximum observed gross
non-volatile beta values will decrease to activities less than detectable levels at a depth of approximately
2.0 ft from the top of the sludge (Figure 11). The radionuclide concentrations are highly correlative (as
expected) with the gross alpha and gross non-volatile beta values for the samples. Because the rapid
reduction of activities is logarithmically correlated with depth, any intervals deeper than 1.25 ft would
represent additional activities of only a fraction of one percent A review of the 3H activities of the basin
sludge and subsoils indicates that 3H activities also decrease rapidly with depth. As previously stated, the
maximum 3H activity within the basin sludge is 15,498 pCi/g, however, the maximum 3H activity at one
foot below the basin sludge is 137.9 pCi/g. A comparison of 3H ratios to the major radionuclides within
the basin suggests that the 3H has reached equilibrium conditions with respect to depth.
-------
Record of Decision for the I.A
-------
Record of Decision for the LAOCB/LAACB (904-83G and 904-79G) (U)
Savannah River Sile
July 1997
\VSKC-RP-97-l43
Revision. I
I'a-jc 3X ol'V2
Figure 11. Cross Alpha and Non-Volatile Beta Concentrations vs. Depth
Log Gross Alpha (pCi/g) (y)
0.25 -
0.5 •-
0.75 •
Depth
(feet)
(x)
1.25 -
1.5 -
1.75 -
2
Background
Concentration
y = -2.7348.x + 4.8421
Log Gross Beta (pCi/g) (y)
0.25
0.5
0.75
Depth
(feet)
(x)
1.25 -
1.5
1.75 -
2
Background
Concentration
2
H-
3
H-
y = -2.5937x + 5.9018
-------
Record ->| IXxiMon tor ihc I. AIM II. I A,\( li <>M)4-X.<( ', am) 'J
Savannah River Site
Jul> l^>7
The rapid decrease in contaminant concentrations with relatively shallow depth is due principally to ihe
presence of dense, kaolinitic clay and iron oxide cemented sediments that underlie the basin and the
surrounding area. This stratigraphic horizon (which is correlatable in the vicinity of the unit) is termed the
"hardpan" and is described in detail in the RFI/RI Report (WSRC, I996a). Figure 12 illustrates the
location of the hardpan relative to the basin and other strata in the vicinity. The moisture content and
hydraulic conductivity of the hardpan beneath the basin appear to be low enough to significantly retard
migration of radionuclides and other contaminants. The sampling of the subsoils below the basin indicates
that the free moisture content of these soils is very low (visual examination suggested that the free moisture
content was probably less than 5 percent). The basin contained approximately 1.5 ft of standing water at
the time of sampling. The moisture content of the subsoils below the sludge versus the hydraulic
conditions of the basin suggests that the hydraulic conductivity of the subsoils/hardpan is very low.
Four volatile organic compounds (VOCs) were detected in the LAOCB sludge -and subsoil at
concentrations exceeding screening levels. All VOCs but methyl. ethyl ketone (MEK) were detei mined to.
be false positives. Reported MEK concentrations are near the screening level and well below risk based
concentrations (RBCs). The LAOCB sludge contains petroleum hydrocarbons with a median observed
concentration of 1 1.34 mg/kg, and a maximum observed concentration of 7186 mg/kg.
Seventeen metals were detected in the LAOCB sludge and subsoil at concentrations exceeding screening
levels. Relatively high concentrations of Cr, Be, Cu, Cd, Pb, and Zn are attributed to decontamination of
stainless steel, galvanized metals, and brass. All 17 metals, except Ba, Co, Cu, Hg, and Zn, exceed RBCs
in at least one sample.
Surface water was collected from two locations in the basin (see Figure 3). Seven radionuclides were
reported in the LAOCB surface water. l37Cs, MCo, and wSr were detected at concentrations exceeding
RBCs and are believed to originate from the LAOCB sludge/organic sediment. 3H activity in the surface
water is very low considering the 3H activity in the sludge. Reported concentrations of 2MBi, 20*TI, and 40K
in the surface water are probably of natural origin. Based on the 1994 sampling and analysis results, there
are no significant concentrations of VOCs present in the surface water in the LAOCB. Nine metals are
reported for the surface water samples collected within the LAOCB, of which only Mn is reported at
concentrations exceeding screening limits. No screening limits are available for Ca, Fe, or K.
Vegetation samples were collected from within the LAOCB security fence to determine the potential
uptake of unit contaminants. For comparative purposes, samples of similar vegetation were also collected
from an unimpacted background reference location. Seven radionuclides were detected in the samples
-------
Rctorcl i>l DCCIMOII for iliu I..A()C»/I.AACn (904-83G and 9IM-79G) (U)
S.IV;IIHI.I|I Kivcr Sue
July 1997
WSRC-RP-'l7-U.i
KcvijHin I
Figure 12. Cross-Section of LAOCB and Surrounding Soils
LEGEND
| | SAND
SILTY/CLAYEY SAND
CLAY
SLUDGE/SEDIMENT
FILL
WATER TABLE
INDEX MAP
A
N. /
f
L-MEA
OIL CHEMICAL
BASIN
< 904-636)
X
A'
SCALE
HORIZONTALt 1 IN • 40 FT
VERTICAL I t IN • 10 FT
-------
Record nf Decision for the l.AOCH.'I.A.AC'U CJlU-X.Ui nnd 90-J-79G) (U) WSRC-RP-97-143
S:ivunn:ili Rucr Silo Revision. I
Jul> IW7 ^ Page 31 of92
analyzed. Mean l' Cs concentrations are significantly higher at the LAOCB than at the reference area for
similar vegetation types with the highest concentrations detected in vegetation collected nearest the water
(black willow, rush, and sedge). In addition, mean concentrations in vegetation are much higher than the
mean concentration of lj7Cs in SRS soils (0.15 pCi/g) estimated by Fay and Pickett (1987). Elevated
levels of lj?Cs detected in the vegetation at the LAOCB are unit-related. Mean "to concentrations in
vegetation at the LAOCB are higher than the trace levels which normally occur in plants and are also likely
to be unit-related. Sixteen metals are reported in the vegetation samples collected in the LAOCB. All
detected metal concentrations from samples collected from the LAOCB are either at or below those
observed in the reference area, are within acceptable background ranges for the SRS, and/or are
ecologically insignificant. In conclusion, the vegetation within the LAOCB security fence is contaminated
with radionuclides from the basin. An ecological risk assessment was performed for selected media within
the LAOCB security fence and the results are discussed in Section VI.
There is no man-made radionuclide contamination of soils outside and adjacent to the LAOCB security
fence. The detected radionuclides are determined to be strictly naturally occurring. Six VOCs and one
semi-volatile organic compound (SVOC) are reported at concentrations exceeding screening limits in soil
samples from locations adjacent to the LAOCB. However, most detections are determined to be suspect
with respect to laboratory data quality, and do not exhibit any apparent trends in vertical or lateral
distribution. Eighteen metals are reported in the soil samples collected adjacent to the LAOCB. Cr, V, Al,
As, and Fe were the only metals reported above screening limits with more than 25 percent frequency. The
reported metals were determined to be naturally occurring and not a result of unit operations. No
pesticides, polychlorinated biphenols (PCBs), dioxins, or furans are reported in any of the soil samples
collected adjacent to the LAOCB.
Soil samples were collected at nine locations along the LAOCB pipelines (see Figure 3). Samples were
collected to a maximum depth of approximately 10 feet below land surface along the pipelines to evaluate
potential leaks which may have occurred during operation. The analytical results indicated elevated
concentrations of naturally occurring radionuclides (e.g., 40K and 20CTI) and metals (e.g., Be and Tl), and
constituents resulting from fanning activities prior to SRS (i.e., As). However, no man-made radionuclide
contamination of soils along the LAOCB pipeline was detected. Several VOCs were detected at
concentrations exceeding screening levels, however, ail but MEK were determined to be laboratory
artifacts. No SVOCs are reported at concentrations exceeding screening levels, and no pesticides or PCBs
are reported in any of the soil samples collected along the LAOCB pipeline. Metal concentrations reported
for samples collected along the LAOCB pipeline are consistent with those reported for the soils adjacent to
the LAOCB described above. Although the analytical results do not indicate significant impact to
-------
RivmJ 41!' Decision lor llic I.A IW' ^ Page 32 of 92
subsurface soils along the LAOCB pipelines, it is anticipated that residual radionuclides, organics, and
metals from leaks in the pipeline may be present in the subsurface soils that were not encountered during
the RFI/RJ sampling activities.
Secondary release mechanisms associated with these sources include volatilization from soil and basin
water, fugitive dust generation from exposed surface soil, biotic uptake, and leaching to ground water. The
most significant of these secondary release mechanisms are the current release of unit contaminants to the
air through fugitive dust generation and leaching to unit groundwater. The quantified risks associated with
these and other exposure routes are summarized in Section VI.
Summary of LAOCB Primary and Secondary Sources
The characterization of the primary and secondary sources associated with the LAOCB indicates that soil
in the LAOCB is highly contaminated with radionuclides. The concentrations of the radionuclides in the
LAOCB sediment tend to decrease rapidly with depth, and generally reach background levels within
approximately two feet from the top of the sediment in the basin. Seven of the radionuclides detected in
the LAOCB soil are also detected above screening levels in the basin surface water. The man-made
radionuclides detected in soils at the site are restricted to the LAOCB and are attributed directly to unit
operations. Metals concentrations in the LAOCB soil are generally above screening limits and are
relatively high, when compared to the LAACB soil and soils from the remainder of the OU. The
occurrence of several of the metals detected above screening levels are attributed to unit operations.
Petroleum hydrocarbons are present in high concentrations in the LAOCB soil and are attributed to unit
operations. Ecological sampling of the basin indicated that 137Cs and MCo were the principal radionuclides
detected in vegetation samples from the LAOCB. These radionuclides have the potential to pose risk to
ecological receptors exposed to contaminated media directly or through the food chain, such as animals
which consume either contaminated vegetation or other animals with bioaccumulated residues of these
radionuclides in their tissues. Based on these data, it is apparent that the media inside the LAOCB have
been significantly impacted by unit operations, and a remedial action is appropriate.
The results of the soil investigation along the LAOCB pipelines indicate that these soils have not been
impacted by unit operations, however, radioactive contamination of the internal surface of the LAOCB
pipelines has been documented to be approximately 300,000 dpm. The pipelines are relatively shallow
(buried less than four feet below land surface) and exposed at one point in a drainage ditch near the Hot
Shop. Both pipelines are constructed of iron pipe and are subject to natural corrosion processes. Based
upon the known radiological contamination associated with the interior of the LAOCB pipelines, and the
-------
KccorJ of Decision lor ihc I.A(X"H/I./\ACH (9(M-S.Ki and 9U4-79G) (U) WSRC-RP-97-14?
Savannah Kucr Site Revision. I
July |'W7 ' I'agc 33 0192
probability the pipe will eventually corrode to the point of allowing the release of fixed/transferable
contamination to the environment, a remedial action to eliminate the potential release of radioactive
contamination from the pipelines is appropriate. In addition, since the concrete drainage pad and
associated piping of the staging area on the north end of the LAOCB are likely contaminated with fixed
and/or transferable radioactive contamination, these components should be remediated at the same time as
the basin remediation.
L-Arca Acid/Caustic Basin
LAACB Primary Sources and Release Mechanisms
Acid/caustic wastewater discharged from the L-Area water treatment plant via the LAACB pipeline was
the primary source. Residual wastewater is no longer present in the LAACB, and its presence in the
pipeline is unlikely because all piping was constructed as gravity feed, and no wastewater has been
discharged through the piping for approximately 30 years.
The primary release mechanisms associated with these sources are deposition inside the basin, deposition
outside the basin from overflow, infiltration and percolation, and leakage of the pipeline (see Figure 10).
»
The most significant of these release mechanisms are the release of unit contaminants to surface soil inside
the basin and from the leakage of wastewater from the pipeline to the subsurface soil along the LAACB
pipeline.
LAA CB Secondary Sources and Release Mechanisms
Secondary sources include organic sediment and subsurface soil in the LAACB, surface water in the basin
that occasionally accumulates from precipitation, and surface and subsurface soil around the basin and in
the effluent ditch south of the basin. Subsurface soil is the only secondary source associated with the
LAACB pipeline since ft is buried approximately six feet below land surface. A detailed sampling and
analysis plan was prepared and implemented to investigate these secondary sources and a complete
description of the sampling methods and protocol are provided in the RFI/RI Report (WSRC, 1996a). No
surface water was present in the LAACB during the RFI/RI, and consequently, no analytical results are
available.
Organic sediment and surface/subsurface soil were collected from two locations within the LAACB (see
Figure 3). Radionuciides, VOCs, and SVOCs were not reported above screening values in the LAACB
-------
Record of Decision for Die LAOCB/LAACU (904-83G and 904-79G) (U) \V.SKC-RI'-';7-M.<
Savannah River Sile Revision I
July l<>97 • |'ai:c 3) nfO
sediment and subsurface soil. Some LAACB sediment samples were reported with oil and grease.
Petroleum hydrocarbons were reported in low concentrations in one sample. Sodium concentrations
exceed screening limits in 90 percent of the samples analyzed and are attributed to the discharge of caustic
soda (NaOH) solutions to the basin. In addition, reported pH measurements are alkaline (11.24 to 11.50)
as would be expected for soils in contact with caustic solutions.
Surface and subsurface soil were collected from four locations adjacent to the LAACB (see Figure 3).
Radionuclide analyses of these samples did not indicate the presence of man-made radionuclides. Based
on these results, there is no radionuclide contamination of soils adjacent to the LAACB. Acetone and
carbon disulfide were the only VOCs reported at concentrations exceeding screening values. However, all
occurrences of these two VOCs were determined to be laboratory artifacts. Bis(2-ethylhexyl)phthalate was
the only SVOC detected above screening limits. All detections were near the detection limit and exhibit no
apparent trends in distribution. No pesticide/PCBs are reported above screening limits in soils adjacent to
the LAACB. No furans and no significant dioxin contamination were reported for soil samples. Based on
these results, there is no organic compound contamination of soils adjacent to the LAACB. Zn, Sb, As, Pb,
Mn, K, and V were the only metals reported at concentrations above screening limits, with Zn being the
only metal reported to exceed screening levels in more than 25 percent of samples analyzed. The
occurrence of metals is consistent with metals detected in the soils adjacent the LAOCB and LAOCB
pipeline, and their presence is not attributed to unit operations. Soil pH measurements generally range
from 5.73 to 7.29 (typical for SRS soils). Lower pH values (2.01 to 2.12) were reported for soils on the
v
east side of the basin, however, follow-up sampling indicated that these low values were due to analytical
error and there is no unit impact to soils on the east side of the basin.
Sixteen metals were detected in the vegetation samples collected in the LAACB. Of the 16 metals that
were analyzed and detected at the basin and that have a significant potential for toxicity, only Cd levels
may be unit-related and elevated above reference levels. Cd concentrations in soils of the LAACB are not
elevated with respect to unit specific soil background. The presence of Cd in unit vegetation at
concentrations above the reference area vegetation concentrations may be a function of soil differences
between the waste unit and the reference area or the natural range of Cd in vegetation, and not due to unit
specific contamination. In addition, if the Cd present in vegetation at the unit was unit related, the
ecological impact of this vegetation would be very low because the vegetation of the unit would represent a
very small percentage of the diet of any potential ecological receptors, and the intake of Cd by any
potential ecological receptors would be negligible. All other detected metal concentrations from vegetation
samples collected from the LAACB are either at or below those observed in the reference area, within
acceptable background ranges for SRS, and/or ecologically insignificant.
-------
Record of Decision for (he LAOCB/I.AACB (904-83G and 904-79G) (U) WSRC-RP-97-M3
Savannah River Site Revision 1
July 1997 Paac 35 ol 92
No radionuclide, VOC, or SVOC contamination is indicated in soils along the LAACB pipeline and
effluent drainage ditch. PCB-1254 and octachlorodibenzo p-dioxin isomers were reported at very low
concentrations and are considered insignificant. Nineteen metals were reported above screening levels
along the pipeline and drainage ditch. Cr, Pb, Se, Mn, V, and Zn are the only metals detected above
screening limits in more than 35 percent of samples analyzed. With the exception of Pb, Mn, and V, all
reported concentrations of the metals are below RBCs. LAACB pipeline and drainage ditch soil sample pH
measurements typically range from 5 to 7.
Secondary release mechanisms associated with these sources include volatilization from soil and basin
water, fugitive dust generation from exposed surface soil, biotic uptake, and leaching to groundwater. The
most significant of these secondary release mechanisms are the current release of unit contaminants to the
air through fugitive dust generation and leaching to unit groundwater. The quantified risks associated with
these and other exposure routes are summarized in Section VI.
Summary of LAACB Primary and Secondary Sources
With the exception of consistently elevated Na concentrations in the LAACB surface/subsurface soil and
the elevated Cd levels in LAACB vegetation, the environmental media associated with the LAACB have
not been impacted by unit operations. No man-made radionuclides, organic compounds, or metals were
consistently identified in unit soils at concentrations above screening levels that would indicate
contamination from unit operations.
•
VI. SUMMARY OF OPERABLE UNIT RISKS
As part of the investigation/assessment process for the LAOCB/LAACB waste unit, a BRA was performed
using data generated during the assessment phase. Detailed information regarding the development of
COPCs, the fate and transport of contaminants, and the risk assessment can be found in the RF1/RJ Report
(WSRC, 1996a) and the Baseline Risk Assessment (WSRC, 1996b).
An exposure assessment was performed to provide an indication of the potential exposures which could
occur based on the chemical concentrations detected during unit-specific sampling activities. The current
land use scenario is an inactive industrial site. The only current exposure scenario identified for the
LAOCB/LAACB was for on-unit visitors, who may perform environmental research such as groundwater
sampling on a limited and intermittent basis at the LAOCB/LAACB. Conservative future exposure
-------
Record of Decision for Ihe LAOCB/l.AACB (904-83G and 904-79G) (U) WSRC-RP-97-143
Sav;mnah Kivcr Silc Revision. I
July 1997 Page 36 of 92
scenarios identified for the LAOCB/LAACB included future on-unit industrial workers and future on-unit
resident adults and children. The future residential scenario includes homegrown produce as an exposure
point, which is not considered under the current on-unit visitor or future industrial worker scenarios. Risks
and hazards from exposures under the three land use scenarios at LAACB and LAOCB are presented in
Tables 2 and 3, respectively. The unit-specific risks for the LAACB and LAOCB are further explained
below.
L-Area Acid/Caustic Basin
The media evaluated in the BRA include soil inside the LAACB, soil adjacent to the LAACB, soil along
the LAACB pipeline, and soil along the LAACB overflow drainage ditch. The BRA concluded that the
LAACB, adjacent area, overflow drainage ditch, and associated pipeline represent low to non-existent risk
(less than 1 x 10* and His less than 1.0) under the current and future on-unit worker scenarios. For the
future on-unit resident, all estimated nonradiological cancer risks were less than 1x10"* except for two
pathways, ingestion of soils 0-2 ft adjacent to the LAACB and ingestion of soils 0-4 ft at the LAACB
pipeline. These risks are very low (approximately 3 x 10"6), and are attributed solely to arsenic and one
dioxin that are not unit related. Therefore, a No Action alternative is proposed for the LAACB. The No
Action alternative will be protective of human health and the environment.
The LAACB will be backfilled with native soil and vegetation will be established in a similar fashion, to the
clean closure of the F-, H-, K-, and P-Acid/Caustic Basins (WSRC, 1995a). Final grade will be sloped to
promote drainage and conform with surrounding terrain. The No Action alternative will be protective of
human health and the environment, and no post ROD documentation or reviews will be necessary.
L-Area Oil A Chemical Basin
The media evaluated in the BRA include soil inside the LAOCB, surface water inside the LAOCB, and soil
adjacent to the LAOCB. Exposure to basin soils represents the greatest risk at the LAOCB. Direct
radiation exposure is the primary risk pathway. The primary contributors to this risk are *°Co and 137Cs.
Results of the BRA are summarized below.
-------
Table 2. Current and Future On-Unit Risks - LAACB
LAACB
Exposure Point
Exposure Route
Soil (0-4 n inside LAACB)
dermal
ingeslion
inhalation
Soil (0-2 n outside LAACB)
dermal
ingeslion
inhalation
Soil (0-4 ft LAACB Pipeline)
dermal
ingeslion
inhalation
Soil (0-1 2 ft LAACB Pipeline)
dermal
ingestion
inhalation
Nonradiological
Current On-Unit
Visitor Risk
NA
NA
NA
2.4E-IO
I.OE-9
I.2E-IO
NA
NA
NA
NA
NA
NA
Nonradiological
Risk Drivers
OCDD95%,As5%
As88%,OCDDI2%
As 100%
Nonradiological
Current On-Unit
Visitor Hazard
NA
NA
NA
3.9E-5
2.8F.-4
38E-5
NA
NA
NA
NA
NA
NA
Nonradiological
Hazard Drivers
OCDD 56%, Pb 22%, Sb 10%
Pb 47%, Sb 22%, Tl 17%
Mn 98%, Pb 2%
Soil was the only media with exposure pathways which were quantified.
NA • Not applicable for this receptor.
NC - Could not quantify due to limited (oxicily information.
Values Tor inhalation of dust and volatiles In air are estimated from COPC concentrations in soil.
?: o
>
I
-*.
73
O
-------
— -J> ja
Table 1 (continued) Current and Future On-Knit Risks - LAACB
LAACB
Exposure Point
Exposure Route
Soil (0-4 A inside LAACB)
dermal
Ingcstion
Inhalation
Soil (0-2 ft outside LAACB)
dermal
Ingestion
inhalation
Soil (0-4 A LAACB Pipeline)
dermal
Ingestion
Inhalation
Soil (0-1 2 ft LAACB Pipeline)
dermal
ingestion
inhalation
Nonradiological
Future On-tlnlt
Worker Risk
NA
NC
NA
NA
3.2E-7
3.8E-8
NA
3.4E-7
5.IE-8
NA
7.9E-8
4.2E-IO
Nonradiological
Risk Drivers
As88%,OCDDI2%
As 100%
As 100%
As 100%
OCDD 100%
OCDD 100%
Nonradiological
Future On-Unit
Worker Hazard
NA
2.0E-2
7.2E-5
NA
1.8E-2
2.4E-3
NA
I.5R-2
I.5C-3
NA
I.5P.-2
I.5E-3
Nonradiological
Hazard Drivers
I'b 100%
Pb 100%
Pb 47%, Sb 22%, Tl 1 7%, As 8%
Mn 98%, Pb 2%
Pb61%.Sh25%. As 12%
Mn 97%, Pb 3%
I'b 39%, Sb 19%, V 17%, llg 14%
Mn95%. Ilg3%, Pb2%
Soil was the only media with exposure pathways which were quantified.
NA • Not applicable Tor this receptor.
NC • Could not quantify due to limited loxicity information.
Values Tor inhalation of dust and volatile* in air are estimated from COPC concentrations in soil.
*1
5
o
r
•a
o
-------
Table 2. (continued) Current and Future On-Unlt Risks - LAACU
a a.
^ O
I.AACO
Exposure Point
Exposure Route
1 Snil (0-4 11 Inside I.AACD)
dermal
ingcslion
inhalation
Soil (0-2 n outside LAACD)
dermal
ingcslion
inhalation
Soil (0-4 n LAACD Pipeline)
dermal
Ingcslion
Inhalation
Soil (0-1 2 l\ LAACD Pipeline)
dermal
Ingeilion
Inhalation
Ingestton of Produce
(0-4 ft Inside LAACB)
leafy
tuberous
fruit
Ingcstion of Produce
(0-2 ft ouuide LAACO)
leafy
tuberous
fruit
NonradioloKical
Future Oii-Unlt
Resident Risk
NC
NC
NC
2.6E-7
2.9E-6
S.5E-8
I.6E-8
3.0E-6
I.IE-7
4.9E-7
7.0E-7
9.3E-IO
NC
NC
NC
4.IE-7
3.9I--7
6.9G-7
,Non radiological
Risk Drivers
OCDD95V.,As5V.
Ai88V,,OCDDI2%
As 100%
As 100%
As 100%
AslOOV.
OCDD 100%
OCUD 100%
OCDD 100%
As 100%
As 100%
As 100%
Nonradiologic.il
Future On-Unil
Resident Hazard
Adult Child
3.6E-3 6.9I--3
I.SE-I 5C-I
I.3E-4 4.2I--4
6.9E-3 I3H-2
I.3E-I 46R-I
4.4E-3 I.4I--2
2.JE-3 27UO
I.IE-I 3.8IM
2.7E-3 SfiL'O
I.OE-2 2.0E-2
I.2E-I 4.013-1
2.8n-3 • 86I--3
3.JE-3 5.3I--3
I.2E-2 I.8I--2
6.IE-2 9IF.-2
I.OE-2 I.6H-2
I.9E-2 2.9I--2
3.6F.-2 54IJ.2
Nonradinlogical
Hazard Drivers
Pn 100%
Pb 100%
Ph 100%
OCDD $6%. Pb 22%, Sb 10%
Pb 47%. Sb 22%. Tl 1 7%, As 8%
Mn 98%, Pb 2%
Pb 65%. Sb 26%. Mn 6%, As 3%
Pb6l%, Sb25%. As 12%
Mn 97%. Pb 3%
OCDR 73%, Pb 1 1%
Pb 39%, Sb 19%. V 17%. MB 14%
Mn9J%. H63%, Pb2%
Ph 100%
Pb 100%
Pb 100%
Mn 65%. As 17%. Pb 14%
Mn6l%. Pb27%.As9%
Ph7l%. Mnl9%. As 9%
(-
o
Soil was the only nxdla with exposure pathways which were quantified.
NA • Not applicable for this receptor.
NC • Could not quantify due 10 limited loxlclly Information.
Values for Inhaurflon of dust and volatile! In air are estimated from COPC concentrations in soil.
VI
73
O
•c ~:
o ='
-------
Table 3. Current and Future On-Unlt Risks - LAOCO
LAOCB
Exposure Point
Exposure Route
Soil (0-2 ft Inside LAOCB)
direct external
Ingesiion
Inhilallon
Soil (0-2 ft outside LAOCB)
direct external
ingestion
Inhalation
Soil (0-4 ft LAOCB Pipeline)
direct external
Ingestion
Inhalation
Soil (0-12 A LAOCB Pipeline)
direct external
Ingestion
inhalation
Radiological
Current On-Unll
Visitor Risk
2.7E-6
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
Radiological Risk Drivers
Co-6091%. Cs-137 5%, Cu-152 3%. Eu-154 1%
LAOCB
Exposure Point
Exposure Route
Soil (0-2 A Imlde LAOCB)
dermal
Ingesiion
inhalation
Soil (0-2 ft outside LAOCB)
dermal .
ingestion
inhalation
Soil (0-4 ft LAOCB Pipeline)
dermal
ingestion
Inhalation
Soil (0-12 11 LAOCB Pipeline)
dermal
Ingestion
inhalation
Nonradiologlcal
Current On-Unlt
Visitor Risk
NA
NA
NA
3.7E-II
I.7E-9
S.4E-9
NA
NA
NA
NA
NA
NA
Nonradiologlcal
Risk Drivers
A»S9%,OCDD4IV.
Ai99%.OCDDI%
CrVI95%,Ai5%
Nonradlological
Current On-Unlt
Visitor Hazard
NA
NA
NA
5.6E-5
3.IU-4
30H-5
NA
NA
NA
NA '
NA
NA
Nonradiologicat
Hazard Drivers
CrVI 72%, Pb 12%, V 6%. Tl 5%
Pb 33%. CrVI 20%. VI 7%,
As 14V., Tl 14%
Mn 98V.. Pb 2%
-.8 2
t'
f
8
?
o
i
Soil was the only media with exposure pathway* which were quantified.
NA • Not applicable Tor this receptor.
NC • Could not quantify due to limited toxlclty information,
Values for inhalation of dust and vol.nloj in air art eillmated from COPC concentrations In soir.
.
I/I
s
-------
Table 3. (continued) Current and Future On-Unit Risks - LAOCO
LAOCB
Exposure Point
Exposure Route
Soil (0-2 ft Inside LAOCB)
direct external
Ingestlon
Inhalation
Soil (0-2 ft outside LAOCB)
direct external
Ingestlon
Inhalation
Soil (0-4 ft LAOCB Pipeline)
direct external
Ingejtlon
Inhalation
Soil (0-12 ft LAOCB Pipeline)
direct external
Ingestlon
Inhalation
Radiological
Future On-Unlt
Worker Risk
2.4E-2
I.5E-4
7.8E-6
NA
NA
NA
NA
NA
NA
2.7E-6
8.9E-9
7.8E-6
Radiological Risk Drivers
Co-6084%.Cs-l37 ll%,Eu-IS24%, Eu-IS4 1%
Am-241 39%, Sr-90 15%. Pu-239 1 1%, U-238 9V., Cm-244 7%. U-234 7%, Cs-137 5%. Co-60 5%
Tc-9997%. U-234 1%, U-238 1%
IUO 77%, 71-20823%
MO 100%
Te-99 97%. U-234 1%, U-238 1%
LAOCB
Exposure Point
Exposure Route
Soil (0-2 ft Inside LAOCB)
dermal
Ingesllon
inhalation
Soil (0-2 ft outside LAOCB)
dermal
Ingesllon
Inhalation
Soil (0-4 ft LAOCB Pipeline)
dermal
Ingestlon
inhalation
Soil (0-12 ft LAOCB Pipeline)
dermal
Ingestlon
Inhalation
Nonradlological
Future On-Unlt
Worker Risk
NA
4.8E-6
I.6E-4
NA
S.2E-7
I.7E-6
NA
2.4E-*
I.IE-7
NA
I.SE-6
I.IE-7
Nonradlological
Risk Drivers
Be 100%
CrVI 95%. As 5%
As99%.OCDDI%
CrVI 9$%. A$ 5%
Be 77%. As 23%
As 72%, Be 17%, Cd 12V.
At 50%, Be 50%
At 88%. Be 6%, Cd 5%
Nonradiological
Future On-Unlt
Worker Hazard
NA
6.6IM
6.8E-3
NA
2.0R-2
I.9E-3
NA
3.6E-I
2.IE-3
NA .
I.5E-1 *
I.3E-3, '
Nonradiological
Hazard Drivers
CrVI 78%. Pb 17%, Al 2%. Nl IV.
Mn 93%, Pb 7%
Ph 33%. CrVI 20%, V 17%,
As 14V.. Tl 14%, Mn IV.
Mn 98%, Pb 2%
Tl 90%, Pb 6%, Al 2%. As 1%
Mn 95%, Pb 5%
Tl 82%, Pb 9%, Al 3%, As 3%
Mn 95%, Pb 5%
Soil was the only media with exposure pathways which were quantified.
NA - Not applicable for this receptor.
NC - Could not quantify due to limited toxlclty Information. '
Values Tor Inhalation of dust and volatile* In air are estimated from COPC concentrations in soil.
>
>
12 3
— - i
o 5' T1
—13 —
-------
Table 3. (continued) Current and Future On-Unit Risks - LAOCB
LAOCB
Exposure Point
Exposure Route
Soil (0-2 ft inside LAOCB)
direct external
Ingcstlon
Inhalation
Soil (0-2 ft outside LAOCB)
direct external
ingestion
Inhalation
Soil (0-4 ft LAOCB Pipeline)
direct external
ingestlon
Inhalation
Soil (0- 12 A LAOCB Pipeline)
direct external
Ingestlon
inhalation
Ingestion of Produce
(0-2 ft Inside LAOCB)
leafy
tuberous
fruit
Radiological
Future On-Unlt
Resident Risk
I.8E-I
6.0E-4
8.9E-6
NA
NA
NA
NA
NA
NA
2.3E-5
3.6E-S
3.4E-I4
9.2E-4
2.9E-3
I.5E-3
Radiological Risk Drivers
Co-6083%,Cs-l2%. Eu-152 4%, Eu-154 1%
Atn-241 40%, Sr-90 14%, Pu-239 1 1%, U-238 9%, Cnt-2-14 7%. U-234 7%. Cs-l 37 5%. Co-60 4%
Tc-99 97%, U-234 1%, U-238 1 %
K-40 82.71-20818%
K-40 100%
MO 100%
Sr-90 96%, Cs-137 3%, U-238 1%
Sr-90 96%, Cs-137 2%. U-234 1%. U-238 1%
Sr-90 69%. Cs-137 30%
V -K
- r.
7>
? 0
"8 £2
2,2
•O
-------
Table 3. (continued) Current and Future On-Unit Risks - LAOCB
LAOCB
Exposure Point
Exposure Route
Soil (0-2 A inside LAOCB)
dcnrml
ingestion
inhalation
Soil (0-2 ft outside LAOCB)
dermal
ingestion
inhalation
Soil (0-4 ft LAOCB 'Pipeline)
dermal
Ingestion
Inhalation
Soil (0-1 2 ft LAOCB Pipeline)
dermal
Ingestion
inhalation
Ingestion of Produce
(0-2 ft Inside LAOCB)
leafy
tuberous
fruit
Ingeslion of Produce
(0-2 ft outside LAOCB)
Icnfy
tuberous
fruit
Nonradiological
Future On-Unlt
Resident Risk
I.IE-6
4.3E-5
3.6E-4
4.0E-8
4.6E-6
3.8E-6
4.4E-7
2.2E-3
2.4E-7
2.1E-7
I.4E-5
2.7E-7
I.8E-6
I.7E-6
3.0E-6
7.5E-7
7.II--7
I.3E-6
Nonradiological
Risk Drivers
Be 100%
Be 100%
CrVI 100%
As59%,OCDD4l%
As99%,OCDDI%
CrVI 95%, As 5%
Be 94%, As 6%
Be 77%, As 23%
As 72%, Be 17%, Cd 12%
Be 83%. As 17%
As 50%, Be 50%
As 88%, Be 6%, Cd 5%
Be 100%
Be 100%
Be 100%
As 100%
As 100%
As 100%'
Nonradiological
Future On-Unit
Resident Hazard
Adult Child
9.7E-I 1 .911+0
4.9E+0 I.7E+I
I.3E-2 4E-2
I.OE-2 I.9E-2
I.5E-I 5.IE-I
3.5E-3 I.II--2
6.5E-2 I.3E-I
2.7E+0 931£+0
3.9E-3 1. 211-2
2.6E-2 5.IE-2
I.IE+0 3.8U+0
2.SE-3 7.7E-3
2.4E-I 3.6E-I
6.7E-I 1.00+0
I.4E+0 2.IOO
I.On-2 lf,P.-2
I.9E-2 2.8i;-2
3.7E-2 5.5E-2
Nonradiological
Hazard Drivers
CrVI 97%, Ph 2%
CrVI 78%. Pb 1 7%, Al 2%
Mn 93%. Pb 7%
CrVI 72%, Pb 12%, V 6%, Tl 5%
Pb 33%, CrVI 20%. VI 7%.
As I4%,TI 14%. Mn 1%
Mn9K%. l'r.2%
Tl 90%. Pb 6%. A 1 l'%. Cd 1%
Tl 90%. Ph 6%. Al 2%. As 1%
Mn 95%, Pb 5%
Tl 84%. Pb 9%, Al 3%, Cd 2%
Tl 82%, Pb 9%. Al 3%. As 3%
Mn 95%, Pb 5%
CrVI50%,Cdl8%,Ni 14%
CrVI66%,Cdll%. Pb 10%
CrVI57%,Pb26%,CdlO%
Mn 44%. As 32%, Pbll%
Mn42%. Pb 22%, CrVI 18%.
Asl7%,TI 1%
Pb 55%, CrVI 16%, As 15%, Mn
I2%,TI 1%
o.
•£
Soil was the only media with exposure pathways which were quantified.
NA - Not applicable for this receptor. ,
NC • Could not quantify due to limited toxlclty Information.
Values for Inhalation of dust and volatile! In air are estimated from COPC concentrations in soil.
•si
c *'
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Record of Decision for Ihc I.AOCH/1.AACH (9IM-83G and 904-79G) (U) W.SRC-Rlp-97-l-T5
-Savannah KIVCI Silc . Revision I
July 1997 Pace 44 ol 92
Current Land Use - Carcinogenic Risks (LAOCB)
Under the current land use scenario, human health risks were characterized for the current on-unit visitor
(see Table 2). The highest estimated radiological cancer risk for any pathway was 3 x 10 from direct
radiation exposure to soils (primarily *°Co) from the LAOCB soil. This risk level is low and within the risk
range for NPL sites. All of the estimated nonradiological cancer risks were less than 1.0 x 10"*.
Current Land Use - Noncarcinogenic Hazards (LAQCB)
Under the current land use scenario, noncarcinogenic hazards were characterized for the current on-unit
visitor. The BRA (WSRC, I996b) shows that potential adverse noncarcinogenic health effects are not
likely to occur, because none of the hazard indices exceed a value of 1.0 (see Table 2).
Future Land Use - Carcinogenic Risks (LAOCB)
For the future on-unit worker, cancer risk from radiological constituents exceeded the 1 x 10~* risk level for
soil ingestion and direct radiation. The highest risk was 2 x 10~2 for direct radiation from LAOCB soils due
principally to MCo and l37Cs (see Table 2). Cancer risks for nonradiological carcinogens were all below
1 x 10"6, except for ingestion and inhalation of the LAOCB soil. The risk from soil ingestion was 4.8 x-10~*
(primarily Be) and the risk from soil inhalation was 1.6 x 10"4 (primarily CrVI).
For the future on-unit resident, cancer risks from radiological exposure exceeded the risk threshold for
exposure to LAOCB soils from direct radiation, ingestion, and ingestion of produce grown in LAOCB
soils. Risks are estimated at approximately 2 x 10'' (primarily *°Co and l37Cs) for direct radiation
exposure, 5 x 10"3 (primarily *°Sr and 137Cs) for exposure from ingestion of produce grown in LAOCB
soils, and 6 x 10"4 (primarily "'Am, *°Sr, and a9Pu) for exposure from LAOCB soil ingestion. Cancer
risks for nonradiological carcinogens exceeded 1 x 10"6. The risk of 4 x Iff4 from inhalation of LAOCB
soils is due primarily to CrVI, the risk of 43 x 10'5 from ingestion of LAOCB soils is due to Be, and the
risk of 3.0 x 10"6 from ingestion of produce inside the basin is due to Be.
Future Land Use - Noncarcinogenic Hazards (LAOCB)
For the future on-unit worker, the His were less than 1.0 for all constituents and exposure pathways.
-------
l-Vo",l ol IVciMon ;.-r ihc I.A« X'li. I..-\At"» C«)4-SW and > "I ''2
For the future on-unit resident, the His exceeded 1.0 for soils at the LAOCB and pipeline. The highest His
for these pathways were for the ingestion of soils, 20 at the LAOCB (primarily from CrVl) and 9 at the
pipeline (primarily from Tl).
Ecological Risk Assessment Results for the LAOCB/LAACB OU
The ecological risk assessment evaluated die likelihood of occurrence for adverse ecological effects from
exposure to chemicals associated with die LAOCB/LAACB OU. The ecological setting of die unit is not
unique. There are no known endangered, threatened, or special concern species on die unit, nor are die
species that inhabit the unit rare in die region or considered to be of special societal value. The area of die
unit is small and the habitat is low in diversity and productivity.
Based on characterization of die environmental setting and identification of potential receptor organisms, a
CSM was developed to determine the complete exposure pathways dirough which ecological receptors
could be exposed to COPCs. The focused evaluation addressed small mammals inhabiting die unit
(represented by the cotton mouse) and amphibians inhabiting die LAACB (represented by die spring
peeper frog). The ultimate assessment endpoint was die biodiversity and health of die ecological
community encompassing die unit.
Interpretation of die ecological significance of die unit-related contamination at me LAOCB/LAACB
indicated diat there was no likelihood of unit-related radiological or nonradiological constituents causing
significant impacts to die community of species in tin vicinity of die unit No constituents of potential
concern identified in die soil ct the LAOCB or LAACB are estimated to pose significant ecological risk
based on dieir toxkhy at dw«QQCcatration at which they are present
COCs and Human Health Risk-Based RGs
The LAOCB soil poses a potential direst to human bealm dirough exposure to sixteen primary COCs (>1 x
10"* risk) and five secondary COCs (1 x 10*4 to 1 x 10~* risk), and die LAOCB pipeline soil poses a
potential threat to human health dirough exposure to four primary COCs and two secondary COCs. The
primary and secondary COCs for die LAOCB soil and LAOCB pipeline soil are presented in Table 4.
RGs were developed for die primary COCs (primarily radtonuclides) which represent greater dian 99 percent
of the total unit risk. RGs are human health risk-based calculations performed on COCs which are primary
contributors of potential risk and/or adverse effects for the future resident scenario. 'B-xz.ix die
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Kcccml o( Decision lor ilic I.AOCH/I.AACH <<>
S.IV .HIM.ill Knot Slle
Julv I9'I7
<•; ;in<1 V04-7')
WSRC-RI'-97-|4%
Revision I
Table 4
Operable Unit COCs and Risk Based RCs
Contaminants of
Concern (COCs)
«&ssem^$&&m^
Americium-241
Antimony- 125
Cesium- 137
Cobalt-60
Curium-244
Europium- 152
Europium- 154
Plutonium-238
Plutonium-239
Potassium-40
Strontium-90
Uranium-238+D
Uranium-234
Uranium-235+D
Aluminum
Cadmium
Chromium
Lead
Nickel
Vanadium
Units
rimary*X>C
pCi/g
PCi/g
PCi/g
pCi/g
pCi/g
pCi/g
pCi/g
pCi/g
pCi/g
pCi/g
PCi/g
pCi/g
pCi/g
pCi/g
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
mg/kg
RGs to Achieve
1E-06 Risk
and HI of 1
Future Resident
Adult and Child
fe
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Record oflX-cision lor I he I A(X'H.'l AAC'H <*M-X3<~i .in4 404-7O<-;) (tj) WSKC-RI'-VT-I JJ
Savannah Ri\cr Sue i'oiMon I
July I'N7 • I'.isc-«?i>f92
hypothetical future scenarios usually yield the most conservative RG, future resident and on-unit worker
RGs are presented in Table 4 for the primary COCs identified for the LAOCB soil and LAOCB pipeline
soil.
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Kt-oir.l ul'Decision lot ilic I.Afx 'H.'I.AAi 'H fXM-XUi .im) «WM-7<»G)
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Kcc •:.! .if [XxKi..n Sir Hie I..-V n H'MAOH (VfW-!T,G .
•i.!i.--:-:-jti Rivci Silc Kcviii.ui I
Jul> I--97 Page -»V of 92
unit and potential remedial technologies becomes available. Final remediation goals will be determined
when the remedy is selected and shall establish acceptable exposure levels that are protective of human
health and the environment
ARARs are those cleanup standards, standards of control, and other substantive requirements, criteria, or '
limitations promulgated under Federal, State, or local environmental law that specifically address a
hazardous substance, pollutant, contaminant, remedial action, location, or other circumstance at a
CERCLA site. Three types of ARARs (action*, chemical-, and location-specific) have been developed to
simplify identification and compliance with environmental requirements. Action-specific requirements set
controls on the design, performance, and other aspects of implementation of specific remedial activities.
Chemical-specific requirements are media-specific and health-based concentration limits developed for
site-specific levels of constituents in specific media. Location-specific ARARs must consider Federal,
State, and local requirements that reflect the physiographical and environmental characteristics of the unit
or the immediate area. There were no action-specific, location-specific, or chemical-specific ARARs
relevant to establishing remedial action objectives for the LAOCB/LAACB source unit
The RF1/RJ and BRA indicate that the secondary sources (i.e., LAOCB soil) associated with die LAOCB
pose significant carcinogenic risk (approximately 2 x 10*1) to human health. Threatened, endangered, or
sensitive species are not found at the LAOCB/LAACB and the unit does not offer attractive or unique
v
cover or forage opportunities for wildlife. Thus, ecological receptors are not at significant risk from the
LAOCB/LAACB OU. In addition, although limited risk b associated with the LAOCB pipeline soils
(approximately 2 x 10"5), radioactivity -detected inside the LAOCB pipelines does pose potential future
risks associated with this source. The RFI/RI ar.d BRA further indicate that risk and hazards to future
residents for the LAACB and its pipeline ire at or below I x 10"* and 1.0, respectively. Therefore, No
Action is warranted ar die LAACB or the LAACB pipeline. Based on these conclusions, the CMS/FS was
conducted to consider possible actions which could reduce the risks associated with die LAOCB soils and
LAOCB pipeline. Since No Action is appropriate for die LAACB, no evaluation of alternatives in die
CMS/FS was warranted for die LAACB.
Based on die risks posed by die radionuclides in die LAOCB soil, die general remedial action objectives
for the LAOCB/LAACB OU are as follows:
I) to reduce risks to human health and die environment associated with:
a) external exposure to radiological constituents
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Ki-o-vr.l ol'Ik-LiMim li'i rli.- I A< X"H/I.AA<"H (O04-«.l(i ami ')().J-7W;) <|J) \VSKC-KP-97-M-''
Vn.inn;ih Kuci Sue Revision I
July 19V7 |>3!:c 50 ol 92
b) inhalation of radiological constituents
c) ingestion of soil or produce grown in soil with radiological constituents, and
d) prevent or mitigate the leaching and migration of COCs to unit groundwater
2) Achieve RGs established for unit soils
The predominant risk drivers at the LAOCB/LAACB OU are radionuclides in the LAOCB soils. Table 3
summarizes the risk posed by LAOCB soil, and illustrates that a majority of the risk is attributed to direct
external radiation from ^Co and lj7Cs, ingestion of 24lAm, '"Sr, and 239Pu, and inhalation of "Tc.
Radionuclides are unique contaminants with a limited selection of remedial responses/technologies.
Consequently, a preliminary list of treatment technologies that are potentially applicable to contamination
associated with radioactive basins at SRS was developed at the Remediation Technology Roundtable,
conducted on January 17 and 18, 1995 (WSRC, 1995c). The Remediation Technology Roundtable
consisted of a panel of technical experts assembled to initiate critical, objective dialogue concerning
potentially feasible remedial technologies and general response actions that could be used at radioactive
waste sites such as the LAOCB. Technical merits and limitations of each technology and general response
action were discussed in the open forum. The results of this forum indicate mat the preferred remedial
responses/technologies are stabilization and containment. The results of this forum, coupled with current
guidance, provided the basis for screening and identifying technologies applicable to radioactive
contaminants, and facilitated the selection of a preferred remedial alternative for the LAOCB in the
CMS/FS and SB/PP.
RGs were developed for the primary COCs (see Table 4) which represent greater man 99 % of the total
unit risk. These target risk based concentrations are for the industrial receptor based on the land-use
determination for the area, and are the acceptable levels of COCs for unit soils that will not pose
unacceptable risk to human health and the environment In general, RGs for radionuclides (activity base)
in soil can only be achieved through off-unit removal/disposal alternatives. Although the preferred
stabilization or containment alternatives will not achieve activity based RGs, these alternatives meet the
remedial action objectives of eliminating the risks posed by direct external radiation, ingestion, and
inhalation of radionuclides and preventing or mitigating the leaching and migration of COCs to unit
groundwater.
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Kt,,.rj .tncCKH.Mt: i li.c l.,V>ru/I.AA< "II <"l|.J-N-,ri .-ind'>i).l--'.« ;),ll) ' \VSKC-Kr-97-UJ
N.:\ .1;.•:.::; Kiv-.T SlU' Kc\ i-.i«'-ll I
JnK r-')~i ^ I'agc 5 I •'< c>2
LAOCB Alternatives
The primary sources associated with the LAOCB (i.e., residual wastewater inside the LAOCB pipeline and
piping associated with the drainage pad) are described in Section V. Residual wastewater is no longer
present in the LAOCB, and its presence in the pipeline is unlikely because all piping was constructed as
gravity feed, and no wastewater has been discharged through the piping for approximately 30 years.
Consequently, remedial alternatives were not developed specifically for these sources.
The secondary sources pose a majority of the unit risk and include the LAOCB soil and LAOCB pipeline.
The CMS/PS included detailed analyses for four LAOCB pipeline and six LAOCB soil alternatives which
are described below. Included with the secondary source alternatives are remedial activities to address the
contaminated vegetation in the LAOCB, the contaminated concrete and associated piping of the drainage
pad on the north end of the LAOCB, and the existing monitoring wells around the basin that are potential
contaminant migration conduits. Since primary and secondary COCs for the LAOCB soil and LAOCB
pipeline soil are radionuclides and metals with very similar physical and chemical properties, the remedial
alternatives identified in the CMSFS are applicable to all unit primary and secondary COCs. These
alternatives do not include discussion of the soil/debris consolidation facility (SCCF), a bulk disposal
option currently under evaluation for the disposal of radiotogically contaminated soils/debris at the SRS. If
built, the SDCF would be located at the SRS and would accommodate low level radioactive soil and debris
* «
from many waste units at the SRS. The feasibility of constructing a SDCF is currently being evaluated and
it is not known if disposal at the SDCF will be a viable option in the future. Therefore, this disposal option
was not considered during the CMS/FS. If, after the ROD has been issued, DOE, EPA, SCDHEC, and
stakeholders decide the LAOCB soil or pipeline should be disposed of at the SDCF, the ROD would be
revised at that time.
Secondary Sear :•• Alternatives (LAOCB)
Alternative S-l. No Action
Under this alternative, no action would be taken at the LAOCB soils. EPA policy and regulations require
consider: -n of the No Acti-rn r'remative to serve as a basis against which other alternatives can be
compared. Because No Action would be taken and the LAOCB soils would remain in their present
condition, there are minimal costs .-slated to normal SRS maintenance activities. The only reduction pf
risks resulting from the No Action alternative would be due to natural radioactive decay. Natural decay of
"Co and i:'Cs, which pose 95% of the risk in the primary risk pathway (external radiation to hypothetical
future resident), would -educe the external radiation risk by nearly 100% and 88%. respectively, over.
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K<.v->iiini ivciM.ni i
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r i::c I ,\< K'H 1 AAO? ("J04-S3O and 9O4-7'X})97 ___^_ I-age 53 of 92
Alternative S-5. Backfill. Install Slurrv Cut-Off Walls around the LAOCB. and Cap
This alternative involves the placement of clean backfill in the LAOCB followed by installation of a
vertical cut-off wall around the LAOCB cap area and construction of a cap over the LAOCB. Initially. th«
waste unit would be prepared by abandoning the existing monitoring wells around the basin and clearing
any vegetation, fencing, and other physical obstructions immediately surrounding the LAOCB area, (n
addition, the contaminated soils, vegetation, and debris on the wails of the basin and the staging area on the
north end of the basin would be pushed into the bottom of the basin. The basin would then be backfilled
and compacted,to grade. After sufficient compaction, a vertical cut-off wall (slurry wail) would be
installed by excavating a trench around the LAOCB down to the hardpan clay layer located just below the
bottom of the LAOCB, and filling with a low permeability soil-ben ton itc or cement-bentonite slurry. An
engineered cap would be constructed over the LAOCB to minimize surface infiltration and reduce the
potential for contaminant migration. Coupled with the hardpan clay layer located just below the .bottom of
the LAOCB, this slurry wall/cap would form a complete low-permeability containment unit.
The tow permeability engineered cap would have the same characteristics as identified in Alternative S-2.
The capped area will be maintained and Institutional Controls will remain in place as long as the waste
remains a threat to human health or die environment.
Under this alternative, remedial action objectives would be satisfied by: (1) limiting infiltration into the
area and thereby preventing the migration of primary and secondary COCs to groundwater, and <2)
preventing hum j; or ecological access and thereby reducing risks to human health and the environment
This alternate e, assuming an approximate backfill/cap thickness of four feet, is estimated to reduce the
radioactive dose (direct radiation exposure) received from *°Co and ""Cs at the LAOCB by nearly 100
percent T-« total present value estimate for this t'rsm;:::-. * is $3,430,000. The-:? costs include operation
and maintenance of die cap for 30 years, and review of remedy every five yea;., for 30 years, as required
by the NC?.
Alternative S-4. In-situ Solidif
This alternative invcives the in-shu solidification/sC^ilization (S/S) of the top two feet of soil in the bottom
of the LAOCB, placement of clean backfill in the LAOCB to grade, followed by construction of a cap over
the LAOCB. Initially, the waste unit would be prepared by abandoning the existing monitoring wells
arouno the basin a.- •• clearing any vegetation, fencing, and other physical obstructions immediately
surrounding the LAOCB area. In addition, the contaminated soils, vegetation, and debris on the walls of
the basin and the staging area on the north end of the basin would be pushed into the bottom of the basin.
The soil and debris would then be solidified/stabilized to a depth of approximately two feet below the
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Record ollX-cision for the I.AOCII/J.AACH <90-J-83<"i and 90-1-79G) (U) wSKC-KI'-97-l«»l
Savannah River Site • Revision I
July 1997 |'a»e 54 ol 92
cun-ent basin bottom. In-situ S/S would involve mixing the S/S reagents into the waste by some
mechanical means such as a jet-grouting system or a long-reach backhoe fitted with a rotary tine. A
treatabiliry study has been conducted on LAOCB soils to identify S/S reagents that effectively immobilize
unit-specific contaminants. A mixture of Portland Cement, bentonite, and sodium silicate was found to
effectively immobilize LAOCB contaminants of concern and would be used to in-situ S/S LAOCB soils.
Following S/S, the remaining depression would be backfilled to grade and a low permeability engineered
cap sufficient to minimize infiltration, intrusion, and surface erosion would be constructed over the basin.
The cover design would be approved by the EPA and SCDHEC prior to construction. The capped area will
be maintained and Institutional Controls will remain in place as long as the waste remains a threat to
human health or the environment.
In-situ S/S does not reduce the total mass of COCs and cannot in itself achieve RGs. However, it is a
proven performance based engineering approach that reduces the mobility of primary and secondary
COCs. Based on results of a literature search and a treatability study performed on LAOCB soils, the in-
situ S/S reagents are considered effective at reducing the teachability of contaminants. Specifically, the
various S/S reagent samples (with LAOCB soil) were subjected to toxicity characteristic leaching
procedure (TCLP) and the extended American National Standard (ANS) 16.1 procedure to simulate
leaching of contaminants over time. Analysis of the two leaching tests performed on LAOCB soil samples
amended with S/S reagents demonstrated that all of the samples released 0.41 % and 1.61 % or less of
gross alpha and gross beta, respectively (WSRC, 1996c).
Under this alternative, contamination in the basin would be immobilized and covered with clean soil and a
cap. These actions would meet remedial action objectives by: (1) preventing infiltration into the area
through capping and immobilizing contaminants present in the basin via in-situ S/S, and thereby
preventing migration of primary and secondary COCs to groundwater, and (2) preventing human or
ecological access and thereby reducing risks to human health and the environment. In addition, assuming
an approximate backfill/cap thickness of four feet, mis alternative is estimated to reduce the radioactive
dose (direct radiation exposure) received from MCo and 137Cs at the LAOCB by nearly 100%. The total
present value estimate for this alternative is $3,580,000. These costs include operation and maintenance of
the cap for 30 years, and review of the remedy every five years for 30 years, as required by the NCP.
Alternative S-S. Ex-situ Stabilize. Backfill. & Cap
This alternative involves the ex-situ S/S of the top two feet of soil in the bottom of the LAOCB, placement
back in the LAOCB, placement of clean backfill in the remaining depression, followed by construction of a
cap over the LAOCB. Initially, the waste unit would be prepared by abandoning the existing monitoring
-------
Kix-ordof IX-rKi.in fftr Ilic l.A IW I'agr 55 of 92
wells around the basin and clearing any vegetation, fencing, and other physical obstructions immediately
surrounding the LAOCB area. Due to radiological control concerns with the excavation of the radioactive
contamination in the basin, the soil would be stabilized prior to excavation for ex-situ S/S. The soil would
be solidified/stabilized to a depth of approximately two feet below the current basin bottom as described
for Alternative S-4. The top two feet of soil in the bottom of the basin would then be excavated and ex-situ
S/S. Following placement of the treated basin soil back in the LAOCB, contaminated soils, vegetation, and
debris on the walls of the basin and the staging area on the north end of the basin would be pushed into the
bottom of the basin on top of the stabilized soil. The basin would be backfilled with clean soil and
compacted to original grade. After sufficient compaction, an engineered cap would be constructed over the
LAOCB. The treated soil and the engineered cap would minimize surface infiltration and reduce the
potential for contaminant migration. The low permeability engineered cap would have the same
characteristics as identified in Alternative S-2. The capped area will be maintained and Institutional
Controls will remain in place as long as the waste remains a threat to human health or the environment
As discussed under Alternative S-4, this alternative does not reduce the total mass of COCs and cannot in
itself achieve RGs. However, it is a proven performance-based engineering approach that reduces the
mobility of primary and secondary COCs. In addition, as discussed under Alternative S-4, results of a
literature search and a treatability study performed on LAOCB soils indicate S/S reagents *--r considered
effective at reducing the mobility of primary and secondary COCs. Under this alternative, contamination
in the basin would be excavated, immobilized, replaced in the LAOCB, and a cap constructed v
This alternative would meet remedial action objectives by: (1) preventing infiltration into the area through
capping and immobf':—rig contamination present in tfae basin 'through ex-shu S/S, thereby preventing
migration of-primary and secondary COCs to groundwater, and (2) preventing human •••r ecological access
and thereby reducing risks to human health and the environment. In addition, assuming an approximate
backfill cap thickness of four feet, this alternative is ^inmted to reduce tfae radioactive dc-.e (direct
radiation exposure) received from *°Co and UTCs at the LAOCB by nearly 100%. Tt-.t *otal present value
estimate for this alternative is 54370,000. "bese costs include operation and maintenance of the cap for 30
years, and tr.e review of remedy every five yeirs for 30 years, as required by the NCR.
Alternative S-6. Excavation & Off-Unit Disposal
This alternative involves the excavation and off-unit disposal of the top two feet of soil from the bottom of
the LAOCB, and contaminated soils, vegetation, and debris on the walls of the basin and the staging area
on the north end of the basin. Treatment (i-e. stabilization) of the LAOCB soils would first be conducted
to ensure optimal waste handling characteristics. Following pretreatment, a backhoe or trackhoe would be
-------
Record ofDccision for ihc LAOCH/LAAOH (904-83G and904-79Ti) (U) U'SKC-RP-97-143
Sjv.iMnali River Stli: Revision. I
July I9V7 I'agc56oi~92
used to excavate contaminated material in the LAOCB to a depth of approximately two feet below the
current basin bottom. Confirmation soil samples would be collected and analyzed periodically during
excavation to verify that all soil exceeding concentration-based remediation goals was recovered.
Following excavation, the soil may require farther treatment for waste handling purposes and packaging
and disposal requirements. The contaminated material would then be placed directly into lined haul trucks
for transport from the waste unit to the disposal facility [Nevada Test Site (NTS) near Mercury, Nevada].
Upon completion of contaminated material removal, the LAOCB would be backfilled with clean soil and
compacted to grade.
By removing the source of contamination, this alternative would eliminate all risks associated with the
LAOCB soils and meet the remedial action objectives by eliminating any risk of contaminant migration to
groundwater and risk to human health and the environment. Since the source term is removed under this
alternative, review of remedy every five years for 30 years would not be required. The total present value
estimate for this alternative is $9,100,000.
Secondary Source A Iternatives (LA OCB Pipeline)
Alternative P-l. No Action
Under this alternative, no action would be taken at the LAOCB pipeline. EPA policy and regulations
*
require consideration of the No Action alternative to serve as a basis against which other altematiyes-can
be compared. Because no action would be taken and the LAOCB pipeline would remain in its present
condition, there are minimal costs related to normal SRS maintenance activities. Under the No Action
alternative, there would be no reduction or mitigation of current or future risks associated with the
pipelines. Since five year reviews of me remedy would be in conjunction with the reviews for the LAOCB
soil remedy, the estimated cost for these reviews for the next 30 years is $0. The total present value
estimate for this alternative is SO.
Alternative P-2. Capping
This alternative involves the construction of a low permeability cap over the LAOCB pipeline area.
Initially, the waste unit would be prepared by clearing any vegetation, fencing, and other physical
obstructions immediately surrounding the LAOCB pipeline area. After the area is prepared, an engineered
cap would be constructed over the LAOCB pipeline to minimize surface infiltration and thereby reduce the
potential for contaminant migration. The low permeability engineered cap would be designed to minimize
infiltration, intrusion, and surface erosion. The cover design would be approved by the EPA and SCDHEC
prior to construction. The cap would cover an area of approximately 0.5 acres (21,780 square feet). The
-------
Kcc. *•! ot'Occr. H'li !"f IW7 I'j^c j7ol'V2
capped area will be maintained and Institutional Controls will remain in place as long as the waste remains
a threat to human health or the environment.
This alternative would meet the remedial action objectives by: (I) minimizing infiltration into the pipeline
area, thereby preventing migration of contaminants to groundwater, and (2) preventing intrusion to the
pipeline area, thereby reducing risk to human health and the environment. Since five year reviews of the
remedy would be in conjunction with the LAOCB soil, the additional estimated present value for these
reviews for the next 30 years is SO. The total present value estimate for this alternative is 5730,000.
Alternative P-3. In-situ Solidification/Stabilization and Disposal in the LAOCB
This alternative involves the in-situ S/S, excavation, and on-unit disposal of the LAOCB pipeline and
associated soils in the LAOCB. The pipelines would first ?e filled with grout to minimize the potential
release of residual contaminants from inside the pipelines during excavation. A backhoe or trackhoe would
then be used to excavate the LAOCB pipeline. The pipelines would be cut into manageable sections for
the purpose af moving and minimizing required disposal space. Confirmation soil samples would be.
collected and analyzed periodically during excavation to verify that all soil exceeding concentration-based
remediation goals was recovered. The pipeline sections and associated soils would be placed directly into
the LAOCB and subsequently solidified/stabilized o create a monolith and further reduce the mobility of
pipeline contaminants. When pipeline and soil removal and disposal are completed, the LAOCB pipeline
area would be backfilled with clean soil and compacted to grade. "
Because the source of contamination would be removed under this alte—ative, remedial action objectives
would be met by eliminating any risk to groundwater, human health, or the environment caused by the
LAOCB F- seline area. Since five year reviews of the remedy would be in conjunction vim the LAOCB
soil, the additional estimated present value for these reviews for the next 30 years is SO. The total present
vilue estimate for tnis alternative is $990,000.
Alternative P-4. [n-situ Solidification/Stabilization and Disposal at the Nevada Test She
This alternative involves the in-situ S/S, excavation, and off-unit disposal of the LAOCB pipeline and
associated soils. The pipelines would first be filled with grout to minimize the potential release of residual
contaminants from inside the pipelines during excavation. A backhoe or trackhoe would be used to
excavate the LAOCB pipeline. The pipeline sections would then be cut into manageable sections for the
purpose of moving and minimizing required disposal space. Confirmation soil samples would be collected
and analyzed periodically during excavation to verify that all soil exceeding concentration-based •
remediation goals was recovered. The pipelines and associated soil would t:-:n be placed directly into
-------
Rccotd of Decision for ihc LAOCH/I.AACH (904-X3G and W-l-7'Kj) X ,if"2
lined haul trucks for transport from the waste unit to the disposal facility (NTS near Mercury, Nevada).
Upon the completion of the excavation of contaminated pipeline and soil, the LAOCB pipeline area would
be backfilled with clean soil and compacted to grade.
Because the source of contamination would be removed under this alternative, remedial action objectives
would be met by eliminating any risk to groundwater, human health, or the environment caused by the
LAOCB pipeline area. Since five year reviews of the remedy would be in conjunction with the LAOCB
soil, the additional estimated present value for these reviews for the next 30 years is $0. The total present
value estimate for this alternative is $4,630,000.
VIII. SUMMARY OF COMPARATIVE ANALYSIS OF THE ALTERNATIVES
Each of the remedial alternatives was evaluated using the nine criteria established by the NCK The criteria
were derived from the statutory requirements of CERCLA Section 121. The criteria are:
overall protection of human health and the environment,
compliance with ARARs,
long-term effectiveness and permanence,
• reduction of toxicity, mobility, or volume through treatment,
short-term effectiveness, ,. >•
implementability,
cost,
state acceptance, and
• community acceptance.
In selecting the preferred alternative, the above criteria were used to evaluate the alternatives developed in
the focused CMS/FS (WSRC, 1997b). Seven of the criteria were used to evaluate all die alternatives,
based on human health and environmental protection, cost, feasibility, and implementability issues. The
preferred alternative was further evaluated based on the final two criteria: state acceptance and community
acceptance.
Tables 5 and 6 present the evaluation of the soil and pipeline remedial alternatives, respectively.
Summaries of the comparative analysis of alternatives are provided below.
-------
Table 5
Comparative Analysis of Soil/Sediment Alternatives
LAOCB
£• -'
r" ?
Criterion
LAOCB Soil Remedial Alternatives
Alternative S-l
No Action
Alternative S-2
Capping
Alternative S-3
Slurry Cut-Off Wall
& Capping
Alternative S-4
In situ S/S &
Capping
Alternative S-5
Ex situ S/S &
Capping
Alternative S-6
Disposal at the
Nevada Test Site
Chemical-specific
Location-specific
Meets
TSCA/UMTRCA
levels; would not
meet 40 CFR 191 or
DOE Order 5400.5
(TBC) under
hypothetical future
conditions
Not Applicable
Meets
TSCA/UMTRCA
levels; Complies
with 40 CFR 191
and DOE Order
5400.5 (TBC)
None
Meets
TSCA/UMTRCA
levels; Complies
with 40 CFR 191
and DOE Order
5400.5 (TBC)
f
r
None
Meets
TSCA/UMTRCA
levels; Complies
with 40 CFR 191
and DOE Order
5400.5 (TBC)
None
Meets
TSCA/UMTRCA
levels; Complies
with 40 CFR 191
and DOE Order
' ,5400.5 (TBC)
None
Meets
TSCA/UMTRCA
levels; Complies
with 40 CFR 191 and
DOE Order 5400.5
(TBC)
!
None
>
n
CO
O o
-------
Table 5 (continued)
Comparative Analysis of Soil/Sediment Alternatives
•LAOCB
Criterion
Action-specific
Long||M
Magnitude of
residual risks
LAOCB Soil Remedial Alternatives
AlternativeS-l
No Action
None
Alternative S-2
Capping
Requires
NESHAPs air
modeling &
permitting; RCRA
cap performance
standards; erosion
control plan;
OSHA worker
health & safety
plan
Alternative S-3
Slurry Cut-Off Wall
& Capping
Requires NESHAPs
air modeling &
permitting; RCRA
cap performance
standards; erosion
control plan; OSHA
worker health &
safety plan
Alternative S-4
In situ S/S &
Capping
Requires
NESHAPs air
modeling &
permitting; RCRA
cap performance
standards; erosion
control plan;
OSHA worker
health & safety
plan
Alternative S-5
Ex situ S/S &
Capping
Requires
NESHAPs air
modeling &
permitting; RCRA
cap performance
standards; erosion
control plan;
OSHA worker
health & safety
plan
Alternative S-6
Disposal at the
Nevada Test Site
Requires NESHAPs
air modeling &
permitting; RCRA
cap performance
standards; erosion
control plan; OSHA
worker health &
safety plan
£»&i&NBMttHHBBIMlflHttttHISfci> ^£2flffift&& >
jjsg^^^^^^^^^^^gggg^jjlfiggj^p ., _ •!;^x,.... ... ... • •'&;•. "i^fi&k .:•
Residual risks could | Much reduced | Residual risks would
be high, particularly
in the absence of
institutional
controls; clay layer
beneath Basin could
retard impact to
groundwater
over current
conditions;
capping and clay
layer would retard
migration of
COCs
be lower than
Alternative 2, total
encapsulation of
COCs
Residual risk
lower than
Alternatives 2 and
3 due to grouting
of the
contaminants
(protection of the
environment)
Residual risk would
be the same as
Alternative 4
Residual risk would
be minimal;
contaminated soils
would be
permanently
removed
>
PC
S.S.?
O yi ^
-------
Table 5 (continued)
Comparative Analysis of Soll/Sedlmcnt Alternatives
LAOCB
Criterion
LAOCD Soil Remedial Alternatives
Alternatives-1
No Action
Alternative S-2
Capping
Alternative S-3
Slurry Cut-Off Wall
&. Capping
Alternative S-4
In situ S/S &
Capping
Alternative S-5
Ex situ S/S &
Capping
Alternative S-6
Disposal at the
Nevada Test Site
3-
r,
>
Adequacy of
controls
Existing
institutional controls
are effective for the
protection of human
health, but cannot
be guaranteed;
adequacy of the clay
layer has proven
effective, but can
not be verified
Existing and
supplemental
institutional
controls would be
effective; cap and
the clay Lycr
beniMth the Haiin
would retard
migration of
COCs
Existing and
supplemental
Institutional controls
would be effective;
slurry wall, cap and
the clay layer
beneath the hasin
would retard
migration of COCs
Existing and
supplemental
institutional
controls would be
effective and
grouting of the.
contaminated soils
would further
limit risk to the
environment
Existing and
supplemental
institutional
conlrols^would be
effective and
grouting of the
contaminated soils
would further limit
risk to the
environment
No controls required;
could be released for
unrestricted land use
I--.. • \-Tt-.fAij
,'lV?,v>:;^'"^.- .
SBi'v':-";"!?--.-..-*."^..-; ;•
Treatment type
No active treatment
No active
treatment
No active treatment
Stabilization/
solidification of
the contaminated
soil
Stabilization/
solidification of the
contaminated soil
None
.
— 1 -c
O ;' T1
-------
Table 5 (continued)
Comparative Analysis of Soil/Sediment Alternatives
LAOCB
's. T:
— •; •*.
Criterion
Reduction of
toxicity, mobility
or volume
Short-Term Effectiv
•1-1. • -IV &
Risk to remedial
workers
Risk to
community
Construction
schedule
AlternativeS-l
No Action
None through
treatment
Alternative S-2
Capping
Capping and the
clay layer beneath
the Basin would
effectively reduce
contaminant
mobility as long as
cap integrity is
maintained; not a
permanent
reduction in
contaminant
mobility
None; would
involve no handling
of contaminated
media
Negligible
Immediately
implementable
Minimal
Minimal
3 months
LAOCB Soil Remedial Alternatives
Alternative S-3
Slurry Cut-Off Wall
& Capping
Slurry wall, capping,
and the clay layer
beneath the Basin
would effectively
reduce contaminant
mobility as long as
cap integrity is
maintained; not a
permanent reduction
in contaminant
mobility
Alternative S-4
In situ S/S &
Capping
Permanently
reduce
contaminant
mobility in the
soils
Alternative S-5
Ex situ S/S &
Capping
Permanently reduce
contaminant •
mobility in the soils
Alternative S-6
Disposal at the
Nevada Test Site
Contaminated soils
removed, and
relocated
.^K&JM&V-
Minimal
Minimal
r
6 months
Low
Minimal
i
t
12 months
Medium; volume of
soils excavated:
760 mj (27,000 ft3,
1,000yd3)
Minimal
15 months
Medium to high;
volume of soils
excavated and
transported: 760 mj
(27,000ft3, 1,000
yd3)
Medium; would
involve transport of
soils to the NTS
3 months
f
•s.
-------
Table 5 (continued)
Comparative Analysis of Soll/Sedimcnl Alternatives
LAOCB
Criterion
LAOCB Soil-Remedial Alternatives
Alternative S-l
No Action
Alternative S-2
Capping
Alternative S-3
Slurry Cut-Off Wall
& Capping
Alternative S-4
In situ S/S &
Capping
Alternative S-5
Ex situ S/S &
Capping
Alternative S-6
Disposal at the
Nevada Test Site
Implemei
Potential concerns
Potential for public
concern if no action
is implemented
Potential for
public concern
since no treatment
is performed
Potential for public
concern since no
treatment is
performed
None
Medium; would
require pre-
excavation
treatment for waste
handling purposes
High; would involve
transport of soils
outside SRS
boundaries; would
require pre- & post-
excavation treatment
for waste handling &
packaging purposes
>
>
Relative
implcmentability
Readily
implementable
Readily
implementable,
but would require
much more effort
than No Action
Readily
implementable;
would require more
effort than capping
alone (Alt 2)
Readily
implementable;
would require
more effort than
capping alone
(Alt 2)
Implementable;
however, waste
handling may cause
down time during
remediation; also
requires pre-
excavation
treatment
Implementable;
however, waste
handling may cause
down time during
remediation; also
requires pre- & post-
excavation treatment
~3
O
-------
Table 5 (continued)
Comparative Analysis of Soil/Sediment Alternatives
LAOCB
Criterion
Basis for O&M
costs
Present worth
capital costs
Present worth
O&M costs
Total present
worth costs
LAOCB Soil Remedial Alternatives
Alternative S-l
No Action
tt^HriUHl
ffi^BH^H
30 years
$0
$280,000
$280,000
Alternative S-2
Capping
30 years
$1,000,000
$430,000
$1,430,000
Alternative S-3
Slurry Cut-Off Wall
& Capping
Alternative S-4
In situ S/S &
Capping
Alternative S-5
Ex situ S/S &
Capping
Alternative S-6
Disposal at the
Nevada Test Site
•^•Bi^iiP :- : ;-.^'--t^iS' ''•••• *
30 years
$3,000,000
$430,000
$3,430,000
30 years
$3,150,000
$430,000
. $3,580,000
30 years
$3,940,000
$430,000
$4,370,000
Not applicable
$9,100,000
$0
$9,100,000
>
X
s
c
•Costs are developed for comparison purposes only and are not intended to forecast actual expenditures.
S/S = Stabilization/Solidification
c- '• ?
* *
-------
Table 6
Comparative Analysis of Pipeline Alternatives
LAOCB
Criterion
r^.crMl Protect, venelv^M^
• •-<«» ••»!• • 'an: *«*?*Sl
Human Health
Environment
Complian^^p^^^^JH
Chemical-specific
Location-specific
Action-specific
Long-Term Effectiveness and
Magnitude of residual risks
LAOCB Pipelines Remedial Alternatives
Alternative P-l No Action
^^^[•^^•••^^•^^••••••••^••M
BHHHH^HHH
Not Protective
Not Protective 1
•i^^^^^^^H^H^BI
Compliance with DOE Order
S400.S cannot be determined
until further investigation is
conducted
None
None
Alternative P-2 Capping
Alternative P-3 In situ S/S
Excavation & Disposal in the
LAOCB
Alternative P-4 In situ S/S
Excavation and Disposal
at the Nevada Test Site
mamm&.-&M.- ^- .
Protective
Protective
lEttAUi* .,'.
Would comply with DOE
Order 5400.5
None
Requires compliance with
RCRA cap performance
standards; erosion control
plan; OSHA worker health &
safety plan
Protective
Protective
Protective
Protective
Ai.-'ij'/Y .-' ' •..•' •••;•••• ;;:.' •''•'•
*£'&•.' •' •. .. ::'.••'•'•.,'
Would comply with DOE
Order 5400.5
None
Requires NESHAPs air
modeling & permitting;
erosion control plan; OSHA
worker health & safety plan
Would comply with DOE
Order 5400. 5
None
Requires NESHAPs air
modeling & permitting;
erosion control plan;
OSHA worker health &
safety plan
fmj^^-^^^- -^^^' •• ••'•
Risk would include intrusion
into the pipeline, and future
release of contaminants due
to degradation of the pipeline
integrity
Residual risks would be
lower than Alternative 1 ;
capping would decrease
access, migration, and
extemaf exposure potential
r
Residual risk would be
minimal; the pipeline would
be grouted \in place and
permanently removed;
contaminants would be
transferred to the basin to be
stabilized further
Residual risk would be
minimal; the pipeline
would be permanently
removed
73
« 0
')» 73 ~
• *~. —•
-------
Table 6 (continued)
Comparative Analysis of Pipeline Alternatives
JLAOCB
Criterion
Adequacy of controls
LAOCB Pipelines Remedial Alternatives
Alternative P-l No Action
Existing pipeline appears to
prevent migration of
radionuclides, but migration
or protection against human
intrusion cannot be
guaranteed
Alternative P-2 Capping
Capping would further
reduce migration of
contaminants by limiting
infiltration
Alternative P-3 In situ S/S
Excavation & Disposal in the
LAOCB
No 'controls required; could
be released for unrestricted
land use
Alternative P-4 In situ S/S
Excavation and Disposal
at the Nevada Test Site
No controls required;
could be released for
unrestricted land use
Reduct^^^>^^^||^^Q^^^^^^^Bffii^Hl^^^bM^%^;: :..:...'::':'•:.
Treatment type
Reduction oftoxicity,
mobility, or volume
No active treatment
None through treatment
No active treatment
None through treatment, but
capping would decrease the
mobility of contaminants
In-Situ S/S
Grouting the pipeline would
reduce mobility
ish6iM^pg^^i^^HlilliiiilHniBii':'f$-i; '
Risk to remedial workers
Risk to community
Construction schedule
None; would involve no
handling of pipelines
Negligible
Immediately implementable
Minimal; would involve no
contact with pipelines
Negligible
f
2 months
Medium; excavation would
require contact with the
pipelines, however residual
contaminants would be
immobilized before handling
Minimal
2 months
In-Situ S/S
Grouting the pipeline
would reduce mobility
• ... .• rt. . .'.•'. .
High; excavation and
loading would require
intimate contact with the
pipelines, however,
residual contaminants
would be immobilized
before handling
Medium; would involve
transport of contaminated
media to the NTS
3 months
-Z =. 3
-------
Table 6 (continued)
Comparative Analysis of Pipeline Alternatives
LAOCR
Criterion
1 m p 1 c rhentabi ljty- •])"••• i;i^;m
Potential concerns
Relative implementability
Cosl^V^;. $;%$£$
IH.isis for O&M costs
Present worth capital costs
Present worth O&M costs
Totiil present worth costs
LAOCB Pipelines Remedial Alternatives
Alternative P-l No Action
mmmmmm
May prompt public concern
Readily implememable
^^"•*™^i|>— "p™**™***^""*"^™**™™"***1
30 years
See Note 2 below
See Note 2 below
See Note 2 below
Alternative P-2 Capping
^^•^^•"•••:t
None
Readily Implementable;
capping would require
significantly more effort than
Alternative 1
Alternative P-3 In situ S/S
Excavation & Disposal in the
LAOCB
•-.'i ;
Medium; would involve
grouting, excavation, rutting
pipeline to manageable
lengths, and exposure to
pipelines
Im'plemcnlable; however,
would require more effort
than Alternative 2 due to
pottnlial for worker
exposure
Alternative P-4 In situ S/S
Excavation and Disposal
at (he Nevada Test Site
i '£'"£•; ' •
High; would involve
grouting excavation,
cutting pipeline to
manageable lengths,
loading, and transport of
pipelines long distance
Implementable; however,
would require more cffori
than Alternative 3 due to
transport
plSMHfflBSt'^''1-;-^.'''!'--^ '- ?'••-'••••.• '•
1 30 years
$560,000
$170,000
$730,000
Not applicable
$990,000
$0
$990,000
Not applicable
$4,630,000
$0
$4,630,000
I. Costs are developed for comparison purposes only and are not Intended to forecast actual expenditures.
2. The cost of remedy reviews would be included in those for the J*AOCB OU, depending on the remedy selected for the LAOCB.
S/S - Stabilization/Solidification
•s.
7:
-------
Record of Decision for ihc LAOCM/I.AACB (90-1-83G and904-79T,) (U) WSRC-RP-97-H3
Savannah River Sue Revision 1
July 1991 I -age t>X of 92
LAOCB Soil Alternatives
Overall Protection of Human Health and the Environment (LAOCB Soil)
The No Action alternative would not be protective of human health and the environment. The existence of
the clay layer (hardpan) beneath the .Basin adequately retards the migration of COGs through the vadose.
zone, however, it provides no means of verifying whether contaminants would impact groundwater in the
future.
Remaining alternatives being considered would all be protective of human health and the environment.
With the exception of Alternative S-6 (Disposal at NTS), all other alternatives would involve capping,
which would: (1) act as a barrier that would deter human access to contaminated media; (2) minimize
infiltration and leaching of contaminants from soil to groundwater; (3) act as shielding to reduce radiation
exposure to hypothetical receptors to within acceptable levels; and (4) serve as redundant protective feature
for those alternatives that involve treatment as a primary means of remediating contaminated soil.
Compliance with ARARs (LAOCB Soil)
The chemical-specific ARARs associated with die LAOCB include concentration-based standards for Ra
and Th in surface and subsurface soil specified in Uranium Mill Tailings Radiation Control -Act
(UMTRCA). No detectable activities of """"Ra, 23*Th, or *3ITh were present in the basin soil. 234Th (a
daughter of niU) was present in significant activities in the basin soil
EPA regulation 40 CFR 192 and DOE Order 5400.5 are considered relevant and appropriate and to-be-
considered information, respectively. The EPA standard specifies an allowable annual effective dose to
any member of the public resulting from nuclear power plant operations. The allowable effective dose rate
is 25 mrem/year. The DOE Order specifies an allowable annual effective dose to any member of the public
resulting from all DOE operations of 100 mrem/year. With the exception of the No Action alternative
(Alternative S-l), an evaluation of remaining alternatives using very conservative assumptions indicates
that implementation of the alternatives would meet the allowable effective dose rates under 40 CFR 192
and DOE Order 5400.5.
Action-specific ARARs identified for the evaluated alternatives are generally similar, however, no ARARs
are identified for the No Action alternative. All remaining alternatives require National Emissions
Standards for Hazardous Air Pollutants (NESHAPs) air modeling, county erosion control plans, and OSHA
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Rv,..:.i.-| IVC.M.MI f,., ilio I ,vX:»/I.AAfli(V04-XjO.!nd9 !9V7 Page 69 of 92
health and safety plans. RCRA capping performance standards are required for all alternatives except No
Action and off-unit disposal. Alternative S-6 requires transportation of radioactive materials within SRS
boundaries and off site to the NTS facility, which would require adherence to DOE Order 5480.3 and 49
CFR 172 through 203.
Long-Term Effectiveness and Permanence (LAOCB Soil)
\
Long-term effectiveness and permanence can be measured in broad terms by (I) the magnitude of residual
risks associated with the waste unit, and (2) the adequacy of controls after implementation of the remedial
alternative. Of the alternatives being considered, the No Action alternative is the least effective alternative
in terms of the magnitude of residual risks after implementation sirce it would leave all,contaminated
media in place without the benefit of treatment. Alternatives S-2 and S-3, which involve the-capping of all
contaminated media and vertical barriers, would significantly reduce the magnitude of residual risks over -
No Action since they would minimize infiltration reaching the waste, nowever, Alternatives S-2 (Capping)
and S-3 (Capping and Slurry Wall) do not involve any form of treatment that would permanently reduce
the magnitude of residual risk. With the exception of No Action (Alternative 5-1) and Alternative S-6
(Disposal at NTS), all other alternatives involve capping and treatment of contaminated media. Alternative
S-6 involves off-unit disposal of all contaminated soil above concentration-based remediation goals but
does not involve capping. Alternatives S-4 (In-shu S/S), S-3 (Ex-situ S/SX and S-6 (Disposal at NTS) offer
a greater reduction in the -nagnhude of residual risks than would Alternatives S-2 (Capping) and S-3
(Capping and Slurry Wall).
Alternatives S-4 (In-situ S/S) and S-3 (Ex-situ S/S) involve some form of meatmen, .hat would
permanently reduce the magnitude of on-unrt residud risks by reducing contaminant mobility and/or
volume. Alternative S-6 involves no form of treatment to reduce the magnitude of residual risk associated
with contaminated media, however, this alternative involves the disposal of ccncaminated soil at die NTS
facility and would ef. Actively remove all residual risk at the unit
With respect co contaminated soil, Alternative S-6 (Disposal at NTSt offers the greatest reduction in
residual rilk since h would permanently remove all contaminated soil at concentrations above
concentration-based remediation goals from the LAOCB waste unit Residual concentrations left in soil
would not pose a significant risk to human health or the environment. Alternatives S-4 (In-situ S/S) and S-
5 (Ex-siru S/S) would immobilize soil-borne contaminants. The residual risks associated with Alternative
S-5 would be slightly less than that of Alternative S-4 because the treatment of all known soil-borne
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Itui-oid ol'IK-cKion lor ilic I.A(K'I!.'I A7-M.>
S.iv.niii:ih Km;i Sue Revision I
July IW7 Page 70 of 92
contamination at the LAOCB waste unit would be verified by confirmation sampling under Alternative S-
5, whereas treatment of all known soil-borne contamination would not be confirmed under Alternative S-4.
Existing SRS institutional controls would be adequate for the protection of human health as long as the
institutional controls are maintained. In the absence of existing controls, the No Action alternative would
not be protective of human health. Based upon the hypothetical scenario that institutional controls cannot
be guaranteed and/or proposed caps could be allowed to fail, the need for controls to maintain
protectiveness would decrease corresponding to the extent to which contaminated media are treated to
permanently reduce the magnitude of residual risks. Consequently, the need for controls is greatest for
alternatives that do not treat or remove any of the contaminated media (Alternatives S-l - No Action, S-2 -
Capping, and S-3 - Capping and Slurry Wall) followed by alternatives that treat all known contaminated
soil at the LAOCB waste unit (Alternatives S-4 - In-situ S/S and S-5 - Ex-situ S/S). Alternative S-6
(Disposal at NTS) would require the least controls of all alternatives being considered since it would
involve the permanent removal of all contaminated soil known to exceed concentration-based remediation
goals. With the exception of restrictions on groundwater use, no controls would be required for the
LAOCB waste unit under Alternative S-6.
Reduction of Toxicitv. Mobility, or Volume (LAOCB Soil)
Alternatives S-l (No Action), S-2 (Capping), S-3 (Capping and Slurry Walls), and S-6 (Disposal at NTS)
offer no form of active treatment and, therefore, do not satisfy the NCP preference for remedial alternatives
that offer a reduction in contaminant toxichy, mobility, or volume. All other alternatives being considered
offer some form of active treatment that would permanently reduce contaminant toxicity, mobility, or
(contaminated media) volume. The treatment technology being considered for treating LAOCB
contaminated soil is stabilization/solidification by grouting (soil only), which reduces contaminant
mobility.
Short-Term Effectiveness (LAOCB Soil)
The short-term risks to remedial workers increases with the volume of contaminated media directly
handled or processed and project duration. Handling (e.g., excavating, moving) and/or processing (e.g.,
treating) contaminated media increases the risk of remedial worker exposure to radiation effects. In
addition, remedial workers are exposed to potential construction-related risks (e.g., falls, cuts, heavy
equipment operation) which increase with corresponding increases in project duration, however, potential
short-term risks to remedial workers should be manageable for all alternatives being considered. With
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Kccordol"Decision l".>r ihc I. A'win \ \( ',', ^alJ-XVi .ni<1 >'04-7
-------
Record of Decision for the I.AOCH/1 .A.ACH (904-830 and 904-79
-------
Kccmd of Decision I'm ihc I.A«~)Cn/I.A.AOt (904-S3G and 90J-79G) (II) WSRC-RP-97-MJ
Sjx aniui:; Ri\\-t Siic . KcvKi.m I
Julj IV9? I'jgc 73 of VJ
The state and Federal regulatory agencies have accepted and approved Alternative S-4 primarily because it
is the least expensive alternative that provides a permanent reduction in contaminant mobility and poses
minimal risk to remedial workers and the community. In addition, based on the public comments received
from the community and the Citizens Advisory Board, Alternative S-4 has met community acceptance.
Comparative Analysis Summary (LAOCB Soil)
The results of the comparative analysis for the LAOCB soil indicate that with the exception of S-l (No
Action), all considered alternatives are comparable with respect to overall protectiveness of human health
and environment, meeting chemical-specific and action-specific ARARs, and relative implementability
(see Table 5). The primary balancing criteria are cost, long-term effectiveness and permanence, and
reduction of toxicity, mobility, or volume. Alternatives S-5 and S-6, although effective in- reducing the
toxicity, mobility, or volume permanently, are estimated in excess of S4 million. In addition, both these
alternatives include significant waste handling and/or transport which increase the potential for remedial
worker and public exposure. Alternative S-3 has an estimated cost comparable to Alternative S-4, but its
ability to reduce contaminant mobility and migration to groundwater over the long-term is not adequate. In
addition, although the estimated cost of Alternative S-2 is significantly less than Alternative S-4, its ability
to reduce contaminant mobility and migration to ground^&ier over the long-term is also not adequate.
%
LAOCB Pipeline Alternatives .
Overall Protection of Human Health and the Environment (LAOCB Pipeline)
Toe No Action Alternative (P-l) would not be protective of human health and toe environment. According
to data gathered during the RF1/KJ, the internal surface of the pipelines exhibit a relatively .ugh
radioactivity «svel (approximately 300,000 dpm cr. internal surface), however, radioisotopes have not been
detected in the pipeline soil or in groundwater from the pipeline areas. This suggests radionuclides have
not migrated from the pipeline to unit soil and groundwater. The No Action Alternative does not prohibit
access to the pipeline areas, and the potential exists for human or wildlife intrusion and subsequent
exposure to the pipelines. Furthermore, based on the s.iallow depth of the pipeline (within three feet of the
ground surface), its relatively high radioactivity level on the internal surface, the age (>30 years) i-id
material of the pipe (steel which could degrade over time and release radioisotopes), Alternative P-l (No
Action) would not be protective of human health or the environment.
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Record of Decision f..r Hie l.AOTB/I./VACH (904-83G and 904-79G) (U) WSRC-RI'-97-l43
S.tvjiiiialt River Silo • Revision I
July 1997 I'aft 7-1 of
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Ki-cori1iirDoci 1^97 IMgj 7? al'V2_
access to the pipelines. Neither Alternatives P-l or P-2 would prevent the potential release of contaminants
to the environment upon the deterioration of the steel pipelines. Alternatives P-3 and P-4 would result in
the least residual risk because they involve removing pipeline contamination from the area.
The adequacy of controls under Alternative P-l cannot be ascertained since the continued maintenance
under institutional controls would not be guaranteed. Alternative P-2 would include the construction of a
cap over the pipeline areas which would require maintenance, but would limit the radiation exposure
potential, decrease the potential for migration, and limit access to the pipelines. Alternatives P-3 and P-4
involve the removal of pipeline contamination and would, therefore, not require any controls following
remediation.
Reduction of Toxicitv. Mobility, or Volume (LAOCB Pipeline) • •_ .
Alternatives P-l and P-2 offer no form of active treatment and, therefore, do not satisfy the NCP preference
for remedial alternatives that offer a reduction in contaminant toxicity, mobility, or volume. However,
Alternative P-2 offers capping which would reduce the mobility of contaminants by minimizing surface
water infiltration, thereby reducing leaching of contaminants to unit groundwater. Alternatives P-3 and P-4
would offer activeMotment through grouting that would reduce contaminant mobility.
Short-Term Effectiveness (LAOCB Pipeline} » »•
The short-term risks to remedial workers increases with project duration. Handling (e.g., excavating,
moving) and/or processing (e.g., treating) contaminated media increases the risk of remedial worker
exposure to radiation effects. In addition, remedial workers are exposed to potential construction-related
risks (e.g., falls, cuts, heavy equipment operation) which increase with corresponding increases in project
duration. Potential short-term risks to remedial workers 4toald be marigeable for all alternatives being
considered. With strict adherence to project hrcidi and vifety plans, h should be possible to maintain
jhort-terro risks of all considered alternatives within acceptable limits.
The potential risk to remedial workers would be lowest for the No ACC.JH alternative, followed by
Alternatives P-2, P-3, and P-4. Alternative P-2 (capping) would not involve any contact with the pipelines.
Alternatives P-3 and P-4 would involve in-shu S/S and excavation and disposal of the pipelines.
Alternative P-4 involves more waste handling due to cutting and packaging of the pipeline for transport.
The risk to remedial workers would be medium under Alternative P-3 and high under Alternative P-4.
Alternative P-3 is estimated to take two months and Alternative P-4 three months.
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Record of Decision f«u the I.AOCn/I.AAOl (901-83G and 904-79G) (U) WSRC-RP-97-U3
S.i\ .inn.ill River Sue Revision. I
July I9>)7 Pa«c76of92
All alternatives would pose negligible or low short-term risks to the community. The risks posed to the
community from Alternatives P-l, P-2, and P-3, would be negligible since they would not include off-unit
transport of contaminated media. Since Alternative P-4 involves transport of contaminated soil to the NTS
facility near Mercury, Nevada, 2,200 miles from the LAOCB waste unit, this alternative involves more risk
than the other alternatives.
Implementability (LAOCB Pipeline)
Alternative P-l (No Action) would be the most implementable alternative being considered since it would
not involve any type of construction or remedial actions beyond existing institutional controls. However,
the No Action Alternative could potentially arouse public concern since it does not involve treatment or
removal of the contamination. Alternative P-2 (Capping) would involve the construction of a cap, but
should be relatively easy to implement. Alternative P-2 should not elicit major public concerns since a cap
would provide a physical barrier between receptors and the pipelines, however, the geometry of the cap
(approximately 450 ft long by 10 ft wide) would cause traffic control and maintenance problems under
current and future land use scenarios. Alternatives P-3 (In-siru S/S and disposal in the LAOCB) and P-4
(In-situ S/S and disposal at NTS) could be readily implementable. S/S is a commonly applied technology
for remediating low-level wastes and should not elicit public concerns. There may be potential public
concern regarding the off-site transportation of low-level waste under Alternative P-4. „ v
Cost (LAOCB Pipeline)
Total estimated present worth costs range between $730,000 for Alternative P-2 (Capping) to $4,630,000
for Alternative P-4 (In-situ S/S, excavation, and disposal at the NTS). The cost of Alternative P-l, No
Action, would be included under the No Action alternative for the LAOCB soils (S-l). Alternative P-2
($730,000) includes capping only. Alternative P-3 ($990,000) involves the grouting, excavation, and
disposal of the pipelines in the LAOCB. Alternative P-4 ($4,630,000) would involve grouting, excavation,
and disposal of the LAOCB pipelines at the NTS.
Alternatives P-l and P-2 would require a remedy review every five years for 30 years because they do not
result in unrestricted use of the pipeline areas. The cost for remedy review would be included with that of
the LAOCB soils, depending on the remedy selected for the LAOCB. Alternative P-2 includes the
operation and maintenance costs of a cap.
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Kccnrd oi Dtcivion lor ihc LAOCI1/1.AACH (tm::li KI\I-I Nile . Revision I
M\ IW7 I'jgc 77 of 92
State and Community Acceptance (LAOCB Pipeline)
Alternative P-I does not provide short or long term proiectiveness of human health and the environment
and consequently has not met state and Federal regulatory acceptance. Alternative P-2 does provide for
reduced contaminant mobility, however, this alternative does not provide a permanent reduction in
contaminant mobility and has not met state and Federal regulatory acceptance. Alternative P-4 does
provide for a permanent reduction in contaminant mobility, however, this alternative includes significant
waste handling and/or transport and is estimated in excess of S4 million. Consequently, Alternative P-4
has not met state and Federal acceptance or community acceptance.
The state and Federal regulatory agencies have accepted and approved Alternative P-3 primarily because it
is the least expensive alternative that provides a permanent reduction in contamir i.it rnobiliry.and poses
minimjl risk to remedial workers and the community. In addition, based on die public comments received
from the community and the Citizens Advisory Board, Alternative P-3 has met community acceptance.
Comparative Analysis Summary (LAOCB Pipeline)
The results of the comparative analysis for the LAOCB pipeline indicate that with the exception of S-l (No
Action), all considered alternatives are comparable with respect to overall protectiveness of hurcan health
and environment, meeting chemical-specific and action-specific ARARs, and relative hnplemercabtliry
(see Table 6). The primary deciding criteria are cost, long-term effectiveness and permanence, and
reduction of toxicfty, mobility, or volume. Alternative P-4, although effective in reducing the toxktty,
mobility, or volume permanently, is estimated in excess of $4 million. In addition, this alternative would
include significant waste transport which would increase die potential for public exposure. Alternative P-2
has an estimated cost comparable to Alternative P-3, however, its ability to reduce contaminant mobility
and migration to grounc. «nuer over the long-term may not be adequate. Alternative P-3 provides a
reduction in contaminant nobility through in-situ stabilization, removal, and further stabilization/disposal
in the LAOCB, is more cost effective than Alternative P-4, and has met state and community acceptance,
IX. THE SELECTED REMEDY
Based on the risks identified in Section VI. the LAOCB soil poses significant risks to human health and the
environment. Significant carcinogenic risks to the potential future worker or resident are driven by
exposure from direct radiation, ingestion of soil, and ingestion of produce grown in the LAOCB soils
contaminated with radionuclides (primarily *°Co and <3?Cs) to a depth of less than rwo feet. In aduition.
-------
Record of Decision for I he I.A
-------
of TVci-.imi lor tlic I.A«XTn/I.AACH fMt-
ili Ri\rr No
remedial action is required; however, the LAACB will be backfilled with native sofl and vegetation will be
established in a similar fashion to the clean closure of the F-. H-, K-, and P-Acid/Caustic Basins (WSRC,
1995a). Final grade will be sloped :o promote drainage and conform with surrounding terrain. The No
Action Alternative will be protective of human health and the environment, and no post ROD
documentation or reviews will be necessary.
In the long-term, if the piupcity is ever transferred to non-Federal ownership, 'Jie U.S. Government will, in
compliance with Section I20(h) of CERCLA. create a deed for die new property owner. The deed shall
include notification disclosing former waste management and disposal activities as well as remedial actions
taken on 3ie site. The deed notification shall, in perpetuity, notify any potential purchaser that the property
has been used for the management and disposal of radioactive oil and chemical wastewater. The deed shall
also include deed restrictions precluding residential use of the property. However, the need for these deed
restrictions may be reevaluated at the time cf transfer in the event that contamination no longer poses an
unacceptable risk under residential use. In addition, if the site is ever transferred to non-Federal ownership,
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Rccordof Decision for the I.AOCH/I-AACH (904-83G and 904-79G) (U) WSRC-Rr-97-H.I
Savannah River Sue Revision I
Jul) 1997 |'.,»c x.) ol •>?.
a survey plat of the area will be prepared by a certified professional land surveyor and recorded with the
appropriate county recording agency.
These selected remedies and the No Action are intended to be the final action for the LAOCB/LAACB
source unit. The solution is intended to be permanent and effective in both the long and short terms. These
. alternatives are considered to be the least cost options which are still protective of human health and the
environment. Further assessment of the groundwater contamination will be conducted to define the extent
of groundwater contaminant plumes under the comprehensive L-Area Southern Groundwater OU. This
assessment will provide the data necessary to conduct a risk assessment, Feasibility Study, Proposed Plan,
and ROD for groundwater in the vicinity of the unit. The SCDHEC has modified the SRS RCRA permit to
incorporate the selected remedy. This proposal is consistent with EPA guidance and is an effective use of
risk management principles.
X. STATUTORY DETERMINATIONS
Based on the LAOCB/LAACB RFI/R1 Report and the BRA, the LAOCB source OU poses significant risk
to human health. Therefore, a determination has been made that in-situ S/S of the pipeline, excavation and
placement of pipeline in the LAOCB, and in-situ S/S and capping of the LAOCB is protective of human
health and environment for the residual contamination in the LAOCB pipeline and LAOCB soil.
v v
The selected remedy is protective of human health and the environment, complies with Federal and State of
South Carolina requirements that are legally applicable or relevant and appropriate to the remedial action,
and is cost-effective. The high levels of radioactive contamination in the LAOCB warrant a remedy in
which in-situ S/S and capping is a practical alternative. In-situ S/S and capping will result in the protection
of unit groundwater through the S/S of unit COCs, and will be protective ofon-unit human and ecological
receptors by shielding radiation exposure and preventing the ingestion of unit COCs.
Based on characterization and risk evaluations, h has been determined that the LAACB source OU poses
no significant risk to human health and the environment A No Action alternative is appropriate for the
LAACB and will be protective of human health and the environment The LAACB will be backfilled with
native soil and vegetation will be established in a similar fashion to the clean closure of the F-, H-, K-, and
P- Acid/Caustic Basins (WSRC, 1 995a).
Section 300.430 (fX^X") of $*e NCP requires that a five year review of the ROD be performed if
hazardous substances, pollutants, or contaminants remain in the waste unit. The three Parties, DOE,
-------
Ki-coi.l of'IVcr.i.m fur tin- I.A'^'IVI.A/VCU ('HM-XVi .in-l >«IJ-~':<~i) (I i) \VSKC-K P-''~-l-) 3
Vi\ ,t:m:ih l»'i\c: "MIC Koi-u'n I
JuK I'/J7 I'jiiv; .SI ..I tl
SCDHEC, and EPA, have determined thai a five year review of the ROD for the LAOCB/LAACB will be
performed to ensure continued protection of human health and the environment.
XI. EXPLANATION OF SIGNIFICANT CHANGES
The SB/PP and the draft RCRA permit modification provided for involvement with the community through
a document review process and a public comment period. A public meeting was advertised and held on
May 7, 1997. Comments that were received during the 45-day public comment period (April 4 - May 18,
1997) are addressed in Appendix A of this Record of Decision and are available with the final RCRA
permit. There were no significant changes to the selected remedy as a result of public comments.
In selecting the remedy in this Record of Decision, a Savannah River Site bulk disposal alternative was not
evaluated in the feasibility study but is currently being developed and evaluated for radiologically
contaminated soils/debris as a SDCF. Should the SDCF concept become a Savannah River Site remedial
option for radiologically contaminated soils prior to implementation of the selected LAOCB and LAOCB
pipeline remedy, then the bulk disposal SDCF alternative will be evaluated for the LAOCB. This
evaluation will fully consider the nine criteria established by the NCP in determining if the SDCF
alternative is an appropriate remedy for the LAOCB and if the SDCF remedy is determined appropriate for
the LAOCB, the change in remedy will cause no significant loss of monetary resources.
v
Should use of the SDCF concept be deemed appropriate for the LAOCB, this Record of Decision would
require modification.
XJL RESPONSIVENESS SUMMARY
There were eight comments received during the public comment period. The Responsiveness Summary
(se* Appendix A) of this Record of Decision addresses these comments.
XIII. POST-ROD DOCUMENT SCHEDULE
The post-ROD document and implementation schedule is summarized below and is illustrated in Figure 13:
1. Corrective Measures/Remedial Design Work Plan (CM/RDWP) (Rev. 0) will be submitted for EPA
and SCDHEC review within approximately I month after issuance of ROD.
2. The combined CM/Rerredial design Report (RDRyRemedial Action Work Plan (RAWP) (Rev. 0)
will be submitted within approximately 4.5 months after issuance of ROD.
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ACTIVITY
DESCRIPTION
EARLV tARLY ORIG
START FINISH DDR
RECORD OF DECISION
EPA/SCOHEC ROD REV. 1 ISSUANCE
17SEPH , 0
CORRECTIVE MEASURE/REMEDIAL DESIGN WORKPLAN
DEVELOP CH/RO WORKPLAN
SRS 9UBHITTAL OF REV.O CN/RDWP
EPA/SCDHtC REVIEW
SRS INCORPORATE tPA/SCHDtC COMMENTS
SRS 6U6HITTAL OF RBV.1 CM/RDWP
EPS/SCHDEC FINAL REVIEW 1 APPROVAL
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CPA/SCOHEC REVIEW
SRS INCORPORATE EPA/SCHOEC COMMEHT3
SRS SUBHITTAL OF RSV.l CM/RDR/RA
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AOCIM.AACB ««*»-*?<; and 904-790.) ,| !)
WSKC-RP-97-141
Rcvi>ion. I
3 Connive Measures/Remcdia, Action start on
LAOCB soi.s and LAOCB pipelines will begin
following EPA and SCDHEC approval of the RDR and RAWP.
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Rccon) of Decision f«rilic LAOOI/l./VACmW-JWi .ind W-i-TH',) (U) WSRC-KI'-''7-M3
^.iv.innnh Riier Nile Kcx KIDII f
XIV. REFERENCES
DOE (U. S. Department of Energy), 1994. Public Involvement. A Plan for Savannah River Sim. Savannah
River Operations Office, Aiken, South Carolina (1994).
DOE, 1 996. Savannah River Site Future Use Project Report. Stakeholder Recommendations for SRS Land
and Facilities (U). Savannah River Operations Office, Aiken, South Carolina (January 1996).
EPA, 1988. Guidance for Conducting Remedial Investigations and Feasibility Studies Under CERCLA,
Interim Final. EPA/540/G-89-004, U.S. EnvironmentaJ Protection Agency, Washington, DC.
Fay, W.M. and J.B. Pickert, 1 987. Documentation of 1982 Soil Analyses to Determine the Natural
Background Radioactivity inSRP Surface Soils. Technical Memorandum to D.E. Gordon, DPST-87-
260. £J. du Pont de Nemours and Company, Savannah River Plant, Aiken, SC.
Fenimore, J.W., J.H. Morton, Jr., K.B. Broom, and N.M. Park, 1988. Radionudides in the Ground at the
Savannah River Plant. DPST-74-319, Rev. I. E.I. du Pont de Nemours and Company, Savannah
River Laboratory, Ajken, SC. — ' '"."*.
WSRC, I993a. Federal Facility Agreement for the Savannah River Site. Appendix C. Docket No. S9-05-
FF, WSRC-RP-94-42, Westinghouse Savannah Rjver Company, Savannah River Site, Aiken, SC.
WSRC, I993b. RCRA Facility Invesligation/R] Program Plan. WSRC-RP-89-994, Revision I.
Westinghouse Savannah River Company, Savannah River Site, Aiken, SC
WSRC, I995a. Closure Plan for the F-. H-. K-. and P-Area Acid/Caustic Basins (U). WSRC-RP-94-J2S9
(Q-CLP-G-00003) Revision 6. Westinghouse Savannah River Company, Savannah River Site, Aiken,
SC.
WSRC, 1 995b. Data Summary far the Data Interpretation and Baseline Risk Assessment of the L-Area Oil
and Chemical Basin, and the Acid/Caustic Basin. WSRC-RP-95-387. Westinghouse Savannah River
Company, Savannah River Site, Aiken, SC. . .
WSRC, I995c. Remediation Technology. Rovndtable Meeting Summary for the Old F-Area Seepage Basin
and L-Area Oil and Chemical Basin. January 17-18. 1995. WSRC-TR-95-0308. Westinghouse
Savannah River Company, Savannah River Site, Aiken, SC.
WSRC, 1996a. RCRA Facility Investigation/Remedial Investigation Report for the L-Area Oil and
Chemical Basin. WSRC-RP-95-305, Revision I. Westinghouse Savannah Riier Company, Savannah
River Site, Aiken, SC.
WSRC, 1996b. Baseline Risk Assessment for the L-Area Oil and Chemical Basin. WSRC-RP-95-387,
Rev. 1. Westinghouse Savannah River Company, Savannah River Site, Aiken, SC.
WSRC, I996c. Laboratory-Scale Immobilization Study Report for the L-Area Oil and Chemical Basin.
WSRC-RP-96-IS, Rev. 0. Westinghouse Savannah River Company, Savannah River Sirs, Aiken, SC.
WSRC, 1997a_ Statement of Basis/Proposed Plan for the L-Area Oil ~nd Chemical Basin and L-Arca
Acid/Caustic Basin. WSRC-RP-96-85 1 , Revision I. Westinghouse Savannah River Company.
Savannah River Site, Aiken. SC.
WSRC, I997b. Phase I Focused Corrective Measures Study/Feasibility Study far the L-Area Oil and
Chemical Basin (U). WSRC-RP-96-106, Rev. I.I. Westinghouse Savannah River Company,
Savannah River Site, Aiken. SC.
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Recoid of Decision for (he LAOCH/LAACB (904-83G and 904-79G) (U) WSRC-RP-97-1-J-;
SavaniKtli River Nile Kcxision I
July 1997 I'a-jcK/ofV:
APPENDIX A
RESPONSIVENESS SUMMARY
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KccorJ olOccisi
N.t\
Julv
on Inr ihc I..-\99
percent) at the LAOCB, the risk posed by the long-lived radionuclides
(e.g., Pu-239) identified in the LAOCB soils is unacceptable.
Since the LAOCB poses unacceptable risk and a remedial action is appropriate, a
CMS/FS was performed to identify appropriate remedial alternatives. The
alternatives were screened in accordance with CERCLA guidance and a detailed
analysis of select alternatives, using the nine evaluation criteria, was performed as
required by the NCP.
The No Action alternative was fully evaluated and rejected, as presented in the
administrative record (CMS/FS), because it would not provide a permanent
reduction hi contaminant mobility. In addition, The No Action alternative may
result in continued groundwater contamination that would require more funding to
address than if the source term (LAOCB soil) were remediated.
EPA and SCDHEC have approved the Statement of Basis/Proposed Plan whkh
recommends in-situ stabilization and capping. In-situ stabilization and capping was
determined to be the least expensive alternative that would provide permanent
reduction of contaminant mobility and meet the statutory requirements of
CERCLA.
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Kccoid of DcciMon for ihc I.AOCH/I.AACH (904-X3G and 90-l-79("i) (U)
S:t\ ;itin.:li KIVCI Sit.
Julv I-J-J7
WSKC-Rr-97-143
Revision I
Comment 2: Groundwater remediation should be considered as pan of the general L-Area
groundwater situation.
Response 2: An area Groundwater Operable Unit (GOU) is proposed in the current FFA
Appendix C and is entitled the L-Area Southern GOU. A schedule for addressing
this GOU is currently under development DOE, EPA, and SCDHEC concur on this
strategy or addressing the groundwater as a separate OU.
Comment 3: Deed restrictions should be placed on the land records now instead of waiting until some
possible future land disposal action by the Federal Government.
Response 3: Deed restrictions are not appropriate or needed at this time and would not apply
until the property is transferred from government ownership. If the property is
ever transferred to non-Federal ownership, a deed will be created and will have
deed notification and deed restrictions. As stated on page 16 of 21 in the Statement
of Basis/Proposed Plan, the need for the restrictions may be reevaluated at the time
of property transfer.
Public Meeting Comments
The following comments were taken from the May 7, 1997 LAOCB Public Meeting transcript. The
following comments are paraphrased from the public meeting transcript during the presentation of the
proposed remedy for this waste unit.
Comment 4: My name is Lee Poe from Aiken, South Carolina, and based on the data provided, my
conclusion is that it is unnecessary, as long as institutional controls are maintained at
SRS. to spend $4.5 million on the remediation of the LAOCB. This conclusion is based
on the following reasons:
1) The remedial action would expose the -workers at SRS to unnecessary fisks.
2) The current risk at the basin is minimal and comparable to risks at other
areas on and off the site.
3) Delaying an action at LAOCB until there is a decision on the land use in the
vicinity of the LAOCB is appropriate.
4) The $4.5 million that we are talking about spending on this remedial activity
should be applied to things at the SRS that have more immediate and real risk
than the risk from this basin to some future population that is a tenuous
situation at best.
These comments are consistent with the Mr. Poe's formal written comments on the
Statement of Basis/Proposed Plan for the LAOCB/LAACB, Revision 1 (February 1997)
submitted to WSRC Public Involvement on April 7. 1997.
Response 4: See response to Comment #1.
Comment 5: My name is Trish McCracken from Augusta. Georgia, and I think it is important to
prioritize projects of this nature at the SRS. The cost and spending are very important
from the taxpayers' standpoint. If my understanding of the data is correct, the current
risk at the LAOCB is low and comparable to many sites across the country. I find it very
surprising that Region IV EPA and the State of South Carolina would impose more cost
at this site than they do at other industrial sites which probably present the same level of
risk. If the regulatory agencies are going to impose these measures at this site, then they
should be imposed across the country.
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Ktcord of IX-cin f.«- i
S.IX .WILlfl Ki\o 7
I AOTH/I.A.
W-S "G and 'MU-7Ofi) (|l)
WSRC-RP-97-I4J
Kct r.ioii t
Page 91 ol V2
Response 5: The LAOCB is the second highest ranking unit with respect to risk as defined in the
FFA. The FFA has been approved and agreed upon by the DOE, EPA, and
SCDHEC. This action is consistent with current environmental laws (i.e., RCRA
and CERCLA) that are enforced by EPA and SCDHEC. DOE concludes that there
is significant risk to the environment and the worker as outlined in Response #1, and
a remedial action is appropriate.
Comment 6: My name is Sam Booher from Augusta. Georgia, and if the decision is to proceed with
the backfill and grouting of the LAOCB. t would like to request that DOB give serious
consideration to removing the liquids, whether it's rainwater, oil, I don't care what the
liquid is, . ^re you pour dirt in there.
Response 6: DOE will consider removal and disposal of the liquids prior to backfilling. These
activities will be detailed in the Remedial Design Report and Remedial Action Work
Plan.
Comment 7: My name is Suzanne Matthews from Aiken, South Carolina, and I do believe that No
Action at this no risk L-Basin is appropriate because the funding is not going to be there.
Now speaking maybe for CAB, the CAB is going to emphasize the priority luting of waste
units at SRS, and they will support the remediation of high risk waste'areas and not the
waste areas with low risk.
Response 7: See response to comment 5. .
CommentS: This is Sam Booher again, and 1 would like to make a suggestion for future public
meetings of this type. I would like to have heard at least a brief summary on each of the
remedial alternatives considered for the LAOCB before presenting the selected remedy.
It seems that of the six considered alternatives, three of them consisted of filling/capping
the basin.
* v
Response 8: A detailed screening and summary of all alternatives considered for the LAOCB is
presented in the CMS/FS and also presented in the SB/PP. These documents have
been approved by EPA and SCDHEC, and are available in the Administrative
Record. P^dionuclides are unique contaminants with a very limited selection of
remedial responses/technologies, with stabilization and containment being the
preferred technologic-. DOE will in the future provide a brief overview of the
alternatives consider.i .it public meetings of this type so that the public may have a
better understanding . t" the rationale for choosing the selected remedies.
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