Superfund Record of Decision Savannah River Site (USDOE) Operable Unit 15 Aiken SC


                                    EPA/ROD/R04-97/027
                                    1997
EPA Superfund
     Record of Decision:
     SAVANNAH RIVER SITE (USDOE)
     EPA ID: SC1890008989
     OU15
     AIKEN, SC
     03/27/1997

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United States Department of Energy

Savannah River Site

Record of Decision
Remedial Alternative Selection for the
D-Area Burning/Rubble Pits (431-D and 431-1D)(U)

WSRC-RP-96-867
Revision 1
February 1997

Westinghouse Savannah River Company
Savannah River Site
Aiken, SC 29808
Prepared for the U.S. Department of Energy under Contract No. DE-AC09-96SR18500

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RECORD OF DECISION
REMEDIAL ALTERNATIVE SELECTION (U)
D-Area Burning/Rubble Pits (431-D and 431-1D)
WSRC-RP-96-867
Revision 1
February 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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DECISION SUMMARY
TABIiE OF CONTENTS

Section Page

I. Site Operable Unit Name, Location, and Description 1
II. Operable Unit History and Compliance History 1
III. Highlights of Community Participation 5
IV. Scope and Role of Operable Unit Within the Site Strategy 6
V. Summary of Operable Unit 6
VI. Summary of Operable Unit Risks 9
VII. Description of the Considered Alternatives 16
VIII. Summary of Comparative Analysis of the Alternatives 18
IX. The Selected Remedy 20
X. Statutory Determinations 26
XI. Explanation of Significant Changes 26
XII. Responsiveness Summary 27
XIII. Post-ROD Document Schedule ,
XIV. References

List of Figures

Figure 1. Location of the D-Area Burning/Rubble Pits in relation to major facilities
at the Savannah River Site 2

Figure 2. Topography of the D-Area Burning/Rubble Pits and surrounding area 3

Figure 3. Topography and Water Table Potentiometric Map of the D-Area Burning/Rubble Pits 4

Figure 4. Schedule for the Corrective Measures Implementation/Remedial Action Report 28

List of Tables

Table 1. Summary of Cacinogenic Risk and Noncarcinogenic Hazards for Current
On-Site Visitors at the D-Area Burning/Rubble Pits 11

Table 2. Summary of Carcinogenic Risk and Noncarcinogenic Hazards for Future
On-Site Workers at the D-Area Burning/Rubble Pits 12

Table 3. Summary of Carcinogenic Risk and Noncarcinogenic Hazards for Future
On-Site Resident Adults and Children at the D-Area Burning/Rubble Pits 13

Table 4. Summary of the Evaluation of Alternative 1 No Action under the Nine
CERCLA Criteria 21

Table 5. Summary of the Evaluation of Alternative 2 Institutional Controls under the
Nine CERCLA Criteria 22

Table 6. Summary of the Evaluation of Alternative 3 Native Soil Cover (4') under the
Nine CERCLA Criteria 23

Table 7. Summary of the Evaluation of Alternative 4 Thermal Desorption/Incineration
under the Nine CERCLA Criteria 24

Table 8. Summary of the Evaluation of Alternative 5 Offsite Soil Disposal under the
Nine CERCLA Criteria 25

Appendix

A. Responsiveness Summary A-l
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DECLARATION FOR THE RECORD OF DECISION

Unit Name and Location

D-Area Burning/Rubble Pits (431-D and 431-1D)
Savannah River Site
Aiken, South Carolina

The D-Area Burning/Rubble Pits (DBRP) (431-D and 431-1D) Waste Unit 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 (SRS).

Statement of Basis and Purpose

This decision document presents the selected remedial alternative for the DBRP located at the
SRS in Aiken, South Carolina. The selected alternative was developed in accordance with CERCLA,
as amended, 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.

Description of the Selected Remedy

The preferred alternative for the DBRP source operable unit soils is Institutional Controls
which will restrict this land to future industrial use. Additional groundwater monitoring, as
discussed in Section IX of the ROD, will also be conducted. Based on the groundwater monitoring
history, the probable condition is that no significant groundwater contamination has originated
from the DBRP. Thus, no remedial action and a period of continued monitoring for confirmation
is the only appropriate action for the groundwater at the DBRP. In the event that the probable
condition of the local groundwater is no longer appropriate, DOE will evaluate the need for
remedial action. Implementation of the Institutional Controls alternative will reguire 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 waste unit which indicate that this area was used
for the disposal of waste material and contains buried waste. In addition, existing SRS access
controls will be used to maintain the use of this site for industrial use only.

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 notification disclosing former
waste management and disposal activities as well as remedial action, 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 construction debris and other materials, including 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 Barnwell County recording agency.

The post-ROD document, the Corrective Measures Implementation/Remedial Action Report (CMI/RAR),
will be submitted to the Regulators four months after the issuance of the ROD. The (CMI/RAR)
will contain a detailed monitoring strategy which will outline the submittal schedule and
contents of the periodic monitoring reports to include: an analysis of the data, a conclusion,
and a recommendation. The regulatory review period, SRS revision period, and final regulatory
review and approval period will be 90 days, 60 days, and 30 days, respectively.
The South Carolina Department of Health and Environmental Control has modified the SRS RCRA
permit to incorporate the selected remedy.

Statutory Determination
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Based on the DBRP RCRA Facility Investigation/Remedial Investigation (RFI/RI) Report and the
BRA, the DBRP source operable unit poses no significant risk to the environment and minimal risk
to human health. Therefore, a determination has been made that Institutional Controls are
sufficiently protective of human health and the environment for the remaining contamination in
the DBRP soils and groundwater. The selected remedy is protective of human health and the
environment, complies with Federal and State of South Carolina reguirements that are legally
applicable or relevant and appropriate to the remedial action, and is cost-effective. The
random distribution and low levels of contamination preclude a remedy in which treatment is a
practical alternative. Because treatment of the principal threats of the site was found to be
impracticable, this remedy does not satisfy the statutory preference for treatment as a
principal element.

Institutional Controls will result in hazardous substances, pollutants, or contaminants
remaining in the waste unit. Section 300.430 (f)(4)(ii) of the NCP reguires that a Five Year
Review of the Record of Decision be performed if hazardous substances, pollutants, or
contaminants remain in the waste unit. The three Parties have determined that a Five Year
Review of the Record of Decision for the DBRP will be performed to ensure continued protection
of human health and the environment.

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I. Site and Operable Unit Name, Location, and Description

The Savannah River Site (SRS) occupies approximately 310 square miles of land adjacent to the
Savannah River, principally in Aiken and Barnwell counties of western South Carolina. SRS is a
secured U.S. Government facility with no permanent residents. SRS is located approximately 25
miles southeast of Augusta, Georgia and 20 miles south of Aiken, South Carolina.

SRS is owned by the U.S. Department of Energy (DOE). Management and operating services are
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.

The Federal Facility Agreement (FFA) lists the D-Area Burning/Rubble Pits (DBRP), 431-D and
431-1D, 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 (RI) to determine the actual or Potential
impact to human health and the environment.

The DBRP are located in the western part of the SRS in Barnwell County, approximately 2600 feet
west of D Area and 1.6 miles west of State Highway 125 (Figure 1). The topography of the area
is flat and the surface of the DBRP is at an elevation of 130 feet above mean sea level and 45
feet above the Savannah River (Figure 2). The water table is approximately 10 feet below ground
surface in the area of the DBRP (Figure 3). Surface drainage is to the west-southwest toward a
nearby ephemeral tributary of the Savannah River.

The two contiguous waste pits are designated as 431-D and 431-1D and cover a total area of 0.54
acre. Approximate dimensions of 431-D are 257 feet by 46 feet by 10 feet, and the dimensions of
431-1D are 229 feet by 36 feet by 10 feet. The two pits are separated by a 15-foot wide berm of
undisturbed soil. The total planar area of the DBRP is assumed to be 257 feet by 97 feet
(24,929 ft #). The pits have been backfilled with soil and vegetation has been established on
the resulting surface. The pit cover is raised above the surrounding terrain, which is
essentially level, to enhance drainage.

II. Operable Unit History and Compliance History

Operable Unit History

Between 1951 and 1973, burning pits were used at SRS to burn a variety of hazardous and non-
hazardous waste. The chemical composition and volumes of the disposed waste are unknown
Combustible materials, which were burned monthly, included paper, plastics, wood, rubber, rags,
cardboard, oil, degreasers, and spent organic solvents. No known or suspected radioactive
materials were allowed in the burning pits.

Burning of waste in the SRS pits was discontinued by October 1973. A layer of soil was then
placed over the residue in the pits and they were subsequently used as rubble pits. Materials
allowed in the rubble pits generally included concrete, bricks, tile, asphalt, plastic, metal,
empty drums, wood products, and rubber. When the pits were filled to capacity in 1983 or were no
longer needed a 1 to 3 foot layer of clayey soil was placed over the contents and the surface
was compacted and mounded above the surrounding terrain, which is essentially level, to enhance
drainage. Vegetation was established to reduce erosion.

Compliance History

At SRS, waste material are managed which are regulated 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) on September 5, 1995.

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Part V 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, 1993) with U.S. Environmental Protection Agency
(EPA) and SCDHEC to coordinate remedial activities at SRS into one comprehensive strategy which
fulfills these dual regulatory requirements.

III. Highlights of Community Participation

Both RCRA and CERCLA require that 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)
R61-79.124 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 DBRP 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 involvement in 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
R61-79.124 and Section 117(a) of CERCLA, as amended require the advertisement at 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 D-Area Burning/Rubble Pits (WSRC 1996c), which is part of the
Administrative Record File, highlights key aspects of the investigation and identifies the
preferred action for addressing the DBRP.

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:

U.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

Reese Library
Augusta State University
2500 Walton Way
Augusta, Georgia 30910
(706) 737-1744

Asa H. Gordon Library
Savannah State University
Tompkins Road
Savannah, Georgia 31404
(912) 356-2183

The public was notified of the public comment period through mailings of the SRS Environmental
Bulletin, a newsletter sent to approximately 3500 citizens in South Carolina and Georgia,
through notices in the Aiken Standard the Allendale Citizen Leader, the Augusta Chronicle, the
Barnwell People-Sentinel, and The State newspapers. The public comment period was also
announced on local radio stations.
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The 45-day public comment period began on September 17, 1996 and ended on October 31, 1996. A
public comment meeting was held on October 15, 1996. A Responsiveness Summary was prepared to
address comments received during the public Comment period. The Responsiveness Summary is
available with the final RCRA permit and is also provided in Appendix A of this Record of
Decision (ROD).
The overall strategy for addressing the DBRP was to:

1) characterize the waste unit delineating the nature and extent of contamination and
identifying the media of concern (WSRC, 1994 and WSRC, 1995b);

2) perform a baseline risk assessment to evaluate media of concern, constituents of concern
(COCs), exposure pathways, and characterize potential risks (WSRC, 1995a);

3) evaluate applicable technologies and isolate a preferred technology to remediate the waste
site as needed (WSRC, 1996b and WSRC, 1996c); and

4) perform a final action to remediate the identified media of concern to the remedial
action objectives.

The DBRP is an operable unit located within the Savannah River Floodplain Swamp Watershed.
Several source control and groundwater operable units within this watershed will be evaluated to
determine impacts, if any, to associated streams and wetlands. SRS will manage all source
control and groundwater operable units, to minimize impact to the watershed. Based on
characterization and risk assessment information, the DBRP does not significantly impact the
watershed. Upon disposition of all source control and groundwater operable units within this
watershed, a final, comprehensive evaluation of the watershed will be conducted to determine
whether any additional actions are necessary. The groundwater at the DBRP was investigated
during the RFI/RI conducted in 1993. The Baseline Assessment (BRA) (WSRC, 1995a) found no risks
exceeding 1.0 x 10 -6 for ingestion of the DBRP soil by future industrial workers, but
calculated a risk of 3.0 x 10 -4 for ingestion of groundwater by future industrial workers.
Additional groundwater monitoring of the groundwater for modeled risk and hazard drivers at the
DBRP will be conducted and reported in the five-year ROD reviews.

V. Summary of Operable Unit Characteristics

The SRS burning/rubble pits were excavated in 1951, during the construction of most of the major
facilities at the Savannah River Plant. The DBRP received waste materials produced during
construction of D-Area facilities. The chemical composition and volumes of the disposed waste
are unknown. During the operation of the burning/rubble pits, combustible materials (including
paper, plastics, wood, rubber, rags, cardboard, oil, degreasers, and spent organic solvents)
were burned monthly, as was the practice at that time, for volume reduction. This practice
would have eliminated many of the combustible organic materials while creating combustion
by-products. No known or suspected radioactive materials were disposed in the burning pits.

Open burning of waste material was discontinued at SRS in 1973. At that time, the waste
residue was covered with soil and the pits were used as rubble pits. Materials allowed in the
rubble pits included concrete, bricks, tile, asphalt, plastic metal, empty drums, wood products,
and rubber. When the pits were filled to capacity about 1993, a 1 to 3 foot layer of clayey
soil was placed over the contents and the surface was compacted, mounded, and seeded.

Media Assessment

The Data Summary Report (WSRC, 1994), BRA (WSRC, 1995a), RFI/RI Report (WSRC, 1995b), and
Corrective Measures Study/Focused Feasibility Study) (WSRC, 1996b) contain detailed analytical
data for all of the environmental media samples taken in the characterization of the DBRP.
These documents are available in the Administrative Record (See Section III).

Soils

Analytical data indicate that little or no contamination of the soil outside of the DBRP has
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occurred. Figure 3 shows the sample locations for the Phase I characterized in 1989 and the
Phase II characterization in 1993. The 1989 program included, two locations in each pit, one in
the berm between the pits, and one directly down gradient of the pits. The 1993 progam
consisted of four soil borings in each pit and four borings around the pits.

In the BRA, the analytical data from the 1993 soil samples were divided into two groups:

• surface soils, 0.0 to 2.0 feet (primary direct contact exposure interval for
soils) and

• subsurface soils, 0.0 to 4.0 feed (potential exposure interval for future scenarios
where excavation may occur).

The BRA identified the following constituents of concern:

arsenic,
benzo(a)pyrene,
chromium,
manganese,
octachlorodibenzo-p-dioxin,
PCB-1260, and
total alpha emitting radium.

Dieldrin was identified as a modeled-DBRP-soils-to-groundwater ingestion risk driver to future
residents, 81% of 8x10 -4 in Revision 0 of the BRA. Dieldrin was only detected two times out of
45 soil samples collected in the DBRP. The maximum value reported was JO.0165 mg/Kg in the 4 to
6 foot interval of boring 11, the "J" gualifier indicates that the analyte was recognized below
detection limits and the value was estimated. The risk contribution of dieldrin was
reevaluated in the BRA, Revision 1 and dieldrin was eliminated as a risk driver based on its
high uncertainty of detection and low number of occurrences.

Two times the mean background value for a constituent was used in screening that constituent
for consideration as a constituent of potential concern. The mean background value for arsenic
at the DBRP is 2.3 mg/kg. In the 0-2 foot interval of the DBRP, arsenic only exceeds 2 times
mean background (4.6 mg/kg, parts per million) at one location, boring 7 (7.6 mg/kg). The
levels of arsenic detected are consistent with the levels found throughout SRS. Arsenic may be
naturally occurring, added to the soils as a pesticide, or a constituent of waste materials
disposed in the DBRP. Arsenic in the soil at SRS is believed to be primarily the residue of
pre-SRS agricultural pesticide application. The occurrence of arsenic will be evaluated on a
site-wide scale in the forthcoming SRS background soils study report.

In the near-surface soil at the DBRP, chromium only exceeded 2 times mean background (80.8
mg/kg) in boring 12 (339 mg/kg). The chromium present in the DBRP is believed to be
predominantly CrIII (chromium in the +3 valence state) which is much less mobile and toxic than
the CrVI (chromium+6) assumed in the BRA evaluation. CrVI is thermodynamically unstable in
soils in the region including SRS and is rapidly reduced to CrIII. Manganese only exceeded 2
times mean background (242 mg/kg) in the near-surface interval in boring 11 (260 mg/kg).

Benzo(a)pyrene (BaP) did not exceed detection limits in the 0-2 foot interval at the DBRP.
Octachlorodibenzo-p-dioxin (OCDD), which comprised only 9% of the risk via soil ingestion for
future on-site workers, was detected at low concentrations in all of the shallow soil samples.
Dioxins are common products of incomplete combustion. Polychlorinated Biphenyl-1260 (PCB-1260)
was identified in only one location, soil boring 12; the maximum concentration of PCB-1260, 3.39
mg/kg, was found in the 0.5-2.0 foot interval. Total alpha emitting radium was only detected in
the 0-2 foot interval (1.2 pCi/g) in boring 7; 2 times mean background was 2.49 pCi/g.

Based on the fad that all the soil analytes passed either the simple site-specific or detailed
site-specific method of screening, there is little or no chance for the residual waste at the
DBRP to be a source of future contamination. The remaining soil contaminants pose little, if
any threat for future contamination.

Groundwater
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Groundwater monitoring data indicate that no significant release of hazardous substances to
groundwater from the DBRP has occurred. However, risk evaluation indicates a groundwater
ingestion risk of 3.Ox 10 -4 for future workers and 1.0 x 10 -3 for future residents due to
arsenic (discussed later in this section). There are 5 monitoring wells in the DBF (D-Area
Burning Pit) well series: DBP-1, -2, -3 (installed in September 1983), DBP-4 installed in June
1994), and DBP-5 (installed in June 1993). Figure 3 shows the locations of the monitoring wells
comprising the DBP network and the potentiometric water table map.

Comparison of constituent concentrations, from!984 through 1992 in the four downgradient DBP
wells with concentrations in the upgradient well, DBP-3, indicates little or no constituent
concentration increase in groundwater after flowing beneath the DBRP. The only constituents
which show any apparent increase are iron, manganese, lead, sulfate, and possibly gross alpha
and total radium. Iron, manganese, and sulfate are covered by the Secondary Drinking Water
Standards which deal with the aesthetic properties of public drinking water. The RCRA
groundwater protection standard for lead is 0.05 mg/L. The highest value of lead reported for
the period of interest was 0.013 mg/L.

The measured groundwater risk drivers under the future resident scenario are: arsenic (dermal,
3 x 10 -6 and ingestion, 1 x 10 -3); dichloromethane (inhalation, 2 x 10 -8); Ra-226 and Ra-228
(ingestion, 2 x 10 -5); and tritium (inhalation, 3 x 10 -9). The modeled-DBRP-soils to
groundwater risk drivers are octachlorodibenzo-p-dioxin (OCDD) and heptachlorodibenzo-p-dioxin
(HpCDD)(dermal, 1 x 10 -4); polyaromatic hydrocarbons (PAH) and 1,1,2-trichloroethane
(1,1,2-TCA) (ingestion, 2 x 10 -4); 1,2-dichloroethane (1,2 DCA) , 1,1,2-TCA, and chloroform
(inhalation, 3 x 10 -5); and tritium (ingestion, 2 x 10 -5 and inhalation, 3 x 10 -5). The
measured groundwater hazard drivers are: manganese (dermal, 1.0); arsenic and manganese
(ingestion, 50.0); and toluene (inhalation, 0.005). The modeled-DBRP-soil-to-groundwater hazard
drivers are: OCDD and HpCDD (dermal, 5.0); acetone and naphthalene (ingestion, 20.0); and
carbon disulfide (inhalation, 0.3). Many of these exposure scenarios are well below the 1 x 10
-6 risk and 1.0 hazard levels.

Arsenic was the sole nonradioactive contributor to risk under the measured groundwater ingestion
pathway in the BRA. The risk to the future on-unit worker was 3.0 x 10 -4; to the future
on-unit resident the risk was 1.0 x 10 -3. The maximum contaminent level for arsenic in drinking
water is 0.05 mg/L. Arsenic was only detected twice in the DBP monitoring network; the higher
value in the December 1993 sample from well DBP-5 was reported as 0.044 mg/L. The following
guarter when the well was resampled, arsenic was reported below detection limits of 0.002 mg/L.
Therefore the risks attributed to this single arsenic value are believed to be exaggerated.

Manganese is covered by the secondary maximum contaminant level of 0.05 mg/L. This contaminant
level addresses the aesthetic properties of public drinking water rather than dealing with
health-based concerns. The maximum value of manganese reported in the DBP well series was 1.44
mg/L from well DBP 2 in the fourth guarter of 1993.

Dichloromethane (methylene chloride), a common laboratory artifact, was only reported in three
soil samples in a total of 55 samples collected from the DBRP with a maximum of V0.06 mg/Kg
(boring 7 at a depth of 4.0-6.0 feet). The "V" gualifier indicates that the analyte was also
detected in the associated method blank, indicating laboratory contamination. The risk
attributed to dichloromethane via the groundwater inhalation pathway by future residents was 2 x
10 -8, well below 1 x 10 -6. Dichloromethane was detected in the groundwater in excess of the
0.005 mg/L maximum contaminant level four times since January 1993, two of these exceedances
were in upgradient well DBP 3. Dichloromethane was evaluated and determined to be a laboratory
artifact. Likewise, acetone has been detected in up- and downgradient wells and is a common
laboratory artifact.

Gross alpha and total radium were the only radioactive constituents, in the Unit Assessment
samples (covering three guarters in 1993) for which primary maximum contaminant levels may have
been exceeded. The maximum contaminant level (MCL) for gross alpha is 15 pCi/L, this level may
have been exceeded in the December 1993 sample from well DBP-2 (15 pCi/L " 0.21 pCi/L). This
gross alpha anomaly occurred only once in a single well that had previously contained no
detectable gross alpha and may be due to field or laboratory contamination.

The MCL (regulatory standard) for total radium is 5 pCi/L; an increase to 20 pCi/L is being
considered under proposed regulations (56FR33050). Total radium in the groundwater has only
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exceeded 5 pCi/L once since monitoring began at ther DBRP. This exceedance occurred in the
sample collected from well DBP-2 in December 1993 (the same sample which yielded the gross alpha
anomaly); Ra-226 was 4.8 pCi/L and Ra-228 was 3.5 pCi/L. The relationship of the gross alpha
and Ra-226/228 anomalies in the same sample suggests that these anomalies could be due to
problems with laboratory or field sampling technigues.

During evaluation performed for the BRA, the assumption was made that all the radium present was
Ra-226, the only radium for which slope factors have been determined and the most toxic radium
species. This assumption contributed to an exaggeration of the risk attributed to radium. The
ingestion of radium in the groundwater pathway risks was evaluated at 6.0 x 10 -6 for future
workers and 2.0 x 10 -5 for future residents.

Tritium was recognized as a risk driver in the modeled-DBRP-soil-to-groundwater exposure pathway
as discussed in the preceeding paragraphs. Tritium only exceeded the two times mean background
screening level (5.26 pCi/g) in the DBRP soils seven times in 49 soil samples, the maximum value
reported was 13.5 pCi/g from the 2 to 4 foot interval in boring 8. The maximum, contaminant
level for tritium is 20,000 pCi/L, the highest value of tritium reported from the groundwater
was only 3400 pCi/L, 17% of the MCL. The maximum modeled-soil-to-groundwater concentration was
11,500 pCi/L.

The PAHs, HpCDD, OCDD, 1,1,2-TCA, 1,2-DCA, carbon disulfide and chloroform, have not been
detected in groundwater. These constituents have very low solubilities in agueous system and
tend to be strongly adsorbed to clays and humates in the soil; they are not readily transferred
from soil to groundwater. The modeling in the BRA is conservative in that it assumes that the
contaminant is present at its maximum detected concentration throughout the waste body and that
the contaminant does not suffer degradation or depletion, thus the modeled-DBRP-soil-to-
groundwater risks are exaggerated.

Under current land use (and recommended institutional controls) the on-site visitor is supplied
with drinking water from the SRS drinking water supply system. Under SRS institutional
control, the local groundwater at the DBRP is not used for drinking or hygienic purposes.

VI. Summary of Operable Unit Risks

Human Health Risk Assessment

As part of the investigation/assessment process for the DBRP waste unit, a BRA was performed
using data generated during the assessment phase. Detailed information regarding the
development of constituents of potential concern (COPCs), the fate and transport of
contaminants, and the risk assessment can be found in the BRA (WSRC, 1995a) and the RFI/RI
Report for the D-Area Burning/Rubble Pits (431-D and 431-1D) (U), (WSRC, 1995b) .

COPCs are site- and media-specific, man-made and naturally occurring, inorganic and organic
chemicals pesticides, and radionuclides detected at a unit under investigation. These
constituents are potentially site-related and data treating their distribution and
concentration, are of sufficient guality for use in the risk assessment. The process of
designating the COPCs was based on consideration of background concentrations, freguency of
detection, the relative toxic potential of the chemicals, and chemical nutrient status.

Constituents of concern (COCs) are isolated from the list of COPCs by calculating carcinogenic
(cancer-causing) risks and noncarcinogenic hazard indices. A COG contributes significantly to a
pathway that contributes to either a cumulative site carcinogenic risk greater than 1.0 x 10 -6
or a hazard index greater than 1.0.

An exposure assessment was performed to provide an indication of the potential exposures which
could occur based on the chemical concentrations detected during sampling activities. The only
current exposure scenario identified for the DBRP was for on-site workers, who may perform
environmental research or maintenance activities (such as mowing and inspections) on the DBRP on
a limited and intermittent basis. Conservative future exposure scenarios identified for the
DBRP included future environmental researchers and maintenance workers and future resident
adults and children. The reasonable maximum exposure concentration value was used as the
exposure point concentration.
-------
Per EPA guidance, the carcinogenic risks and noncarcinogenic hazards must be calculated to
determine the appropriate remedial action for a waste unit. Carcinogenic risks are estimated as
the incremental probability of an individual developing cancer over a lifetime as a result of
pathway-specific exposure to cancer-causing contaminants. These risks are expressed as the
increased likelihood that an exposed individual will develop cancer during his lifetime (70
years) because of a 30-year (chronic) exposure to the contaminants at a given waste site.

Cancer risks are related to the EPA target risk range of one in ten thousand (1.0 x 10 -4) to
one in one million (1.0 x 10 -6) for incremental cancer risk at National Priorities List sites.

Remedy selection, addressing significant risks and/or principal threat source material, was
completed in a comprehensive Corrective Measures Study/Feasibility Study (CMS/FS). Alternatives
that are permanent and/or employ treatment as a principal element of the remedy are necessary
for inclusion in the CMS/FS.

Non-carcinogenic effects are also evaluated to identify a level at which there may be concern
for potential health effects other than cancer. The hazard guotient which is the ratio of the
exposure dose to the reference dose, is calculated for each contaminant. Hazard guotients are
summed for each exposure pathway to determine the specific hazard index (BD for each exposure
scenario. If the hazard index exceeds unity (1.0), there is concern that adverse health effects
might occur.

Exposure risks and hazard for the three land use scenarios are presented in Tables 1 through
3. 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.

Current Land Use-Noncarcinogenic Hazards

Under the current land use scenario, human health risks and noncarcinogenic hazards were
characterized for the current on-unit visitor. An on-unit visitor is described as an employee
of SRS who works at the DBRP for short periods on an infreguent basis, (i.e., a few hours per
month performing environmental sampling or maintenance activities). Current on-unit visitors
are supplied with drinking water from the SRS drinking water supply system; the local
groundwater is not used for drinking or hygiene.

The BRA (WSRC, 1995a) shows that potential, adverse noncarcinogenic health effects are not
likely to occur, because none of the hazard indices exceeds a value of one. Table 1 contains
a summary of noncarcinogenic hazards under the current land use scenario.

Current Land Use - Carcinogenic Risks

Under the current land use scenario, human health risks were characterized for the current
on-unit visitor. Table 1 contains a summary of carcinogenic risks. All of the estimated
nonradiological cancer risks were less than 1.0 x 10 -6, indicating that carcinogenic risk from
the unit is not significant. Media evaluated include soil inside the DBRP, soil outside the
DBRP, associated airborne soil particulates, and surface water and sediment in the
stream/wetland.

All of the estimated radiological risks were less than 1.0 x 10 -6. Radiological risks were
estimated for three exposure pathways: ingestion of soil inside the DBRP, inhalation of
particulates from soil inside the DBRP, and ingestion of sediment.

Future Land Use - Noncarcinogenic Hazards

The His were less than one, indicating adverse noncarcinogenic effects are unlikely for the
following pathways:

• direct exposure of on-unit workers to soils inside and outside the DBRP (Table 2)
• direct exposure of adult and child residents to soils inside and outside the DBRP
(Table 3)
• direct exposure of child-only residents to soils inside and outside the DBRP
• exposure of a child to surface water and sediment
-------

The groundwater ingestion and inhalation pathway yielded a HI of 50 from arsenic and
manganese to future resident adults and children. This hazard is reduced to 6 for future
on-unit workers.

Future Land Use - Carcinogenic Risks

Several exposure pathways for the future on-unit resident had estimated nonradiological
carcinogenic risks exceeding the lower bound of the target risk range, 1.0 x 10 -6 (Tables 2 and
3). No contamination was found in concentrations that yielded risks greater than the upper bound
of the risk range of 1.0 x 10 -4 except for arsenic by groundwater ingestion. Under the
groundwater ingestion pathway, the risk due to arsenic to the future on-unit worker was 3.0 x
10 -4; to the future on-unit resident the risk was 1.0 x 10 -3. These risks were based on a
single measured arsenic value in the groundwater which was less than the MCL for drinking
water.

For the future on-unit worker, cancer risks for ingestion of soil from inside the DBRPs were
egual to the EPA point of departure of 1.0 x 10 -6 for the 0-2.0 foot and 0-4.0 foot depth
intervals. Estimated risks for dermal contact with soil and inhalation of soil particulates at
both depths inside the DBRP were egual to 1.0 x 10 -6.

Ecological Risk Assessment

Based on characterization of the environmental setting and identification of potential receptor
organisms, a conceptual site model was developed to determine the complete exposure pathways
through which receptors could be exposed to COPCs.

Interpretation of the ecological significance of the unit-related contamination at the DBRP
indicated that there was essentially no likelihood of unit-related chemicals causing significant
impacts to the community of species in the vicinity of the unit.

Site-Specific Considerations

Site-specific considerations, based on the conclusions of the BRA and RFI/RI, which suggest
limited or no potential, for significant risk include:

1) The DBRP contain a large volume of buried non-hazardous waste material and cover soil.

2) The levels of contamination recognized during Phase II characterization are generally very
low; there is a preponderance of non-detects. The contaminants are very stable chemically and
exhibit limited mobility in the soil.

3) The groundwater monitoring program indicates that there has not been significant impact from
the waste material in the pits.

4) The DBRP are in a remote area which has been recommended as a future industrial zone by the
Citizens Advisory Board (CAB) and in the Savannah River Site Future Use Project Report (DOE,
1996).

Remedial Action Objectives

Remedial action objectives specify unit-specific contaminants, media of concern, potential
exposure pathways, and remediation goals. The remedial action objectives are based on the
nature and extent of contamination, threatened resources, and the potential for human and
environmental exposure. Initially, preliminary remediation goals are developed based upon
Applicable or Relevant and Appropriate Reguirements (ARARs), or other information from the
RFI/RI Report and the BRA. These goals should be modified, as necessary, as more information
concerning the 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.

Risk levels at or above the upper-bound of the target risk range 1.0 X 10 -4 are considered
significant and are expected to undergo remediation.

Location-specific ARARs must consider Federal, State, and local reguirements that reflect the
physiographical and environmental characteristics of the unit or the immediate area. Remedial
actions may be restricted or precluded depending on the location or characteristics of the unit
and the resulting reguirements.

None of the risks associated with the soil in the DBRP was found to be greater than 1.0 x 10 -4.
PCB-1260 from the 0-2 foot soil interval in Pit 431-D was the predominant risk driver for future
residents, contributing 79% of the 1.0 x 10 -5 risk.

The hazard index for this exposure scenario was 0.7. The only guidance that was exceeded for
soil concentrations was for PCB-1260 which had a maximum value of 3.39 mg/kg in the 0-2 foot
interval of boring 12 in Pit 431-D. The to-be-considered guidance for PCBs is recommended soil
action levels of 1.0 mg/kg for residential use and 10-25 mg/kg for industrial use (EPA, 1990).
The PCB-1260 concentration in Pit 431-D is well below the range for industrial land use.

VII. Description of the Considered Alternatives for the DBRP Source Control Operable Unit

The RFI/RI and BRA indicate the DBRP pose minimal risk to the environment. The risk to future
on-unit workers is only 1.0 X 10 -6. Ingestion of soil in the top two foot layer by future
residents poses a risk of 1.0 x 10 -5, primarily from PCB-1260. The Corrective Measures
Study/Focused Feasibility Study (CMS/FFS) was developed to consider possible actions which could
reduce the risks to 1.0 x 10 -6 or less.

A broad suite of treatment alternatives has already been considered in the F-Area Burning/Rubble
Pits (231-F, 231-1F and 231-2F) Corrective Measures Study/Feasibility Study (U) (WSRC, 1996a).
Both sets of burning/rubble pits received similar wastes which were managed under similar
conditions and practices; similar constituents of concern have been recognized for both
facilities. On July 20, 1995, SRS, SCDHEC, and EPA held a scoping meeting for the DBRP CMS/FS.
The agenda of this meeting included discussion of the site specific considerations and
uncertainties, the limited risks associated with the DBRP, and the CAB proposed industrial land
use zones. The conclusion of the scoping meeting was that focusing on a limited suite of
alternatives in the feasibility study for the DBRP would be appropriate. Therefore, SRS
conducted the CMS/FFS (WSRC, 1996b) for the DBRP, reducing the number of treatment options to be
considered to the five alternatives discussed in the following paragraphs.

Five alternatives were evaluated for remedial action at the DBRP source control operable unit.
Each alternative is described below:

Alternative 1 No Action

Under this alternative, no action would be taken at the DBRP. EPA policy and regulations
reguire consideration of a no action alternative to serve as a basis against which other
alternatives can be compared. Because no further action would be taken and the DBRP would
remain in their present condition, there are no costs associated with this alternative and there
would be no reduction of risk. Potential risks of 1.0 x 10 -5 due to soil ingestion and 1.0 x
10 -3 from ingestion and inhalation of groundwater would remain for possible future residents.
However, the groundwater risk is believed to be overestimated based on the groundwater
monitoring history and contaminant concentrations in the DBRP soil as discussed in Section V.

Alternative 2 Institutional Controls

Under this alternative, institutional controls would be implemented at the DBRP. Implementation
of this alternative will reguire both near- and long-term actions. For the near-term, signs
will be posted indicating that this area was used to manage hazardous materials. In addition,
existing SRS access controls will be used to maintain the use of this site for industrial use
only.

In the long-term, if the property is ever transferred to non-federal ownership, the U.S.
-------
Government would create a deed for the new property owner in compliance with Section 120(h) of
CERCLA. The deed would include notification disclosing former DBRP waste management and
disposal activities, results from groundwater monitoring, and remedial actions taken on the
site. The deed notification would, in perpetuity, notify any potential purchaser that the
property has been used for the management and disposal of non-hazardous, inert construction
debris, and that wastes containing hazardous substances, such as degreasers and solvents, were
also managed and burned on the site.

The deed would also include deed restrictions precluding residential use of the property.
However, the need for these deed restrictions could be reevaluated at the time of 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, a survey plat of the area
will be prepared, certified by a professional land surveyor and recorded with the appropriate
county recording agency.

There are no construction costs associated with this alternative. The cost for surveying the
land and filing with the Barnwell County Records is estimated to be $2,000. If five year reviews
of remedy are reguired, the estimated present value for these reviews over the next 30 years is
$8,000. The total present value costs for Alternative 2 are $10,000. Additional groundwater
monitoring and reporting costs would total about $12,000 annually; these costs may not continue
indefinitely and are not included in the total cost used for comparison.

With essentially no further action except for the modest cost of deed notifications and
restrictions upon transfer of the land and five year reviews, under Alternative 2 Institutional
Controls, risks attributable to future workers at the DBRP would be 1.0 x 10 -6.

Alternative 3 Native Soil Cover (4')

A four foot thick cover of natural soil would be installed over the present surface of the DBRP
to reduce the likelihood that future excavation for construction of a typical basement would
expose waste or contaminated soil. If the property is ever transferred to private ownership, in
compliance with CERCLA 120(h), the U.S. Government would create a deed with notifications and
restrictions similar to those identified in Alternative 2. Future deed restrictions on
excavation below four feet would be necessary to prevent potential exposure of future workers or
residents to buried waste which may contain low concentrations of hazardous constituents.

The preparation of a Remedial Design/Remedial Action Work Plan would cost $30,000. The
construction costs associated with this alternative are estimated at $160,000 for the
installation of a four foot thick native soil cover. The cost for surveying the land and filing
with the Barnwell County Records is estimated to be $2,000. Maintenance costs for 30 years are
estimated at $15,000. If five year reviews would be reguired; the estimated present value for
these reviews over the next 30 years is $8,000. Total present value costs for this alternative
are estimated at $235,000.

With deed restrictions upon the transfer of the land to non-federal ownership per Section 120(h)
of CERCLA, the risk to future workers and possible future residents would be reduced to less
than 1.0 x 10 -6. The need for the deed restrictions would be reevaluated prior to transfer.

Alternative 4 Thermal Desorption/Incineration

Under this alternative, the upper two feet of contaminated soil would be excavated for treatment
to eliminate the PCB-1260, BaP, and OCDD. The soil would be fed through a high temperature
rotary kiln to extract the volatile organic contaminants from the soil. The extracted gases
would then be destroyed in the incinerator. The treated soil would be returned to the site and
vegetation would be established to prevent erosion. If the property is ever transferred to
private ownership, in compliance with CERCLA 120(h), the U.S. Government would create a deed
with notifications and restrictions similar to those identified in Alternative 2. Future deed
restrictions (upon transfer of the land to non-federal ownership) on excavation below two feet
would be necessary to prevent potential exposure of future workers or residents to buried waste
which may contain low levels of hazardous constituents. The need for these deed restrictions
could be reevaluated at the time of transfer in the event that contamination no longer poses an
unacceptable risk under residential use.
-------
Preparation of the Remedial Design/Remedial Action Work Plan to implement this alternative
would cost $150,000. A National Emission Standards for Hazardous Air Pollutants permit would be
required at a cost of $150,000 because of the potential for atmospheric releases during
remediation. The treatment cost for this alternative would be $1,500,000 and the deed
restriction on excavation below two feet would cost $2,000 for a total cost of $1,502,000.

This alternative is protective of human health and would permanently reduce risk to less than
1.0 x 10 -6 for ingestion of soil from PCB-1260 for future on-site workers and future residents.

Alternative 5 Offsite Soil Disposal

Under this alternative, the upper two feet of contaminated soil would be excavated and
transported to a licensed offsite disposal facility. The excavation would be filled to grade
with clean native soil and cover vegetation would be established. If the property is ever
transferred to private ownership, the U.S. Government would create a deed with notifications and
restrictions similar to those identified in Alternative 2 in compliance with CERCLA 120(h). The
potential risk for exposure of future workers and possible residents to low concentrations of
hazardous constituents in the remaining waste would necessitate the filing of a deed restriction
on excavation below two feet upon the transfer of the land to non-federal ownership. The need
for these deed restrictions could be reevaluated at the time of transfer in the event that
contamination no longer poses an unacceptable risk under residential use.

The preparation of a Remedial Design Remedial Action Work Plan would cost $150,000. The cost
for excavation, transportation, disposal fees, and backfilling would be $932,000. The total
cost for this would be $1,084,000, including $2,000 for recording the deed notifications and
restrictions.

The risk to future workers and possible future residents would be reduced to less than 1.0 x
10 -6 from ingestion of PCB-1260 contaminated soil.

VIII. Summary of Comparative Analyses of the Alternatives

Description of Nine Evaluation Criteria

Each of the remedial alternatives was evaluated using the nine criteria established by the
National Oil and Hazardous Substances Contingency Plan (NCP). The criteria were derived from
the statutory requirements of CERCLA Section 121. The NCP [40 CFR ° 300.430 (e)(9)] sets forth
nine evaluation criteria that provide the basis for evaluating alternatives and selecting a
remedy. 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 mentioned criteria were used to evaluate the
alternatives developed in the D-Area Burning/Rubble Pits (431-D and 431-1D) Corrective Measures
Study/Focused Feasibility Study (U) (WSRC, 1996b). Seven of the criteria are used to evaluate
all the alternatives, based on human health and environmental protection, cost, and feasibility
issues. The preferred alternative is further evaluated based on the final two criteria: state
acceptance and community acceptance. Brief descriptions of all nine criteria are given below.

Overall Protection of Human Health and the Environment - The remedial alternatives are assessed
to determine the degree to which each alternative eliminates, reduces, or controls threats to
human health and the environment through treatment, engineering methods, or institutional
controls.

Compliance with Applicable or Relevant and Appropriate Requirements - ARARs are Federal
-------
and state environmental regulations that establish standards which remedial actions must meet.
There are three types of ARARs: (1) chemical-specific, (2) location-specific, and (3) action-
specific.

Chemical-specific ARARs are usually health- or risk-based levels or methodologies which, when
applied to unit-specific conditions, result in the establishment of numerical values. Often
these numerical values are promulgated in Federal or state regulations.

Location-specific ARARs are restrictions placed on the concentration of hazardous substances or
the conduct of activities solely because they are in specific locations. Some examples of
specific locations include floodplains, wetlands, historic places, and sensitive ecosystems or
habitats.

Action-specific ARARs are usually technology- or remedial activity-based reguirements or
limitations on actions taken with respect to hazardous substances or unit-specific conditions.
These reguirements are triggered by the particular remedial activities that are selected to
accomplish a remedy.

The remedial activities are assessed to determine whether they attain ARARs or provide grounds
for involving one of the five waivers for ARARs. These waivers are:

• the remedial action is an interim measure and will become a part of a total remedial
action that will attain the ARAR,

• compliance will result in greater risk to human health and the environment than
other alternatives,

• compliance is technically impracticable from an engineering perspective,

• the alternative remedial action will attain an eguivalent standard of performance
through use of another method or approach,

• the state has not consistently applied the promulgated reguirement in similar
or at other remedial action sites in the state.

In addition to ARARS, compliance with other criteria, guidance, and proposed standards that are
not legally binding, but may provide useful information or recommended procedures should be
reviewed as To-Be-Considered when setting remedial objectives.

Long-Term Effectiveness and Permanence - The remedial alternatives are assessed based on their
ability to maintain reliable protection of human health and the environment after
implementation.

Reduction of Toxicity, Mobility, or Volume Through Treatment - The remedial alternatives are
assessed based on the degree to which they employ treatment that reduces toxicity (the harmful
nature of the contaminants), mobility (ability of the contaminants to move through the
environment), or volume of contaminants associated with the unit.

Short-Term Effectiveness - The remedial alternatives am assessed considering factors relevant to
implementation of the remedial action, including risks to the continuity during implementation,
impacts on workers, potential environmental impacts (e.g., air emmissions), and the time until
protection is achieved.

Implementability - The remedial alternatives are assessed by considering the difficulty of
implementing the alternative including technical feasibility, constructability reliability of
technology, ease of undertaking additional remedial actions (if reguired), monitoring
considerations , administrative feasibility (regulatory reguirements), and availability of
services and materials.

Cost - The evaluation of remedial alternatives must include capital and operational and
maintenance costs. Present value costs are estimated within +50/-30 percent, per EPA guidance.
The cost estimates given with each alternative are prepared from information available at the
time of the estimate. The final costs of the project will depend on actual labor and material
-------
costs, actual site conditions, productivity competitive market conditions, final project scope,
final project schedule, and other variable factors. As a result, the final project costs may
vary from the estimates presented herein.

State Acceptance - In accordance with the FFA, the State is required to comment on/approve the
RFI/RI Report, the Baseline Risk Assessment, the Corrective Measures Study/Feasibility Study,
and the Statement of Basis/Proposed Plan.

Community Acceptance - The community acceptance of the preferred alternative is assessed by
giving the public an opportunity to comment on the remedy selection Process. A public comment
period was held and public comments concerning the proposed remedy are addressed in the
Responsiveness Summary of this Record of Decision.

Detailed Evaluation

The remedial action alternatives discussed in Section VII have been evaluated using the nine
criteria just described. Tables 4 through 8 present the evaluation of the soil remedial
alternatives.

IX. The Selected Remedy

Based on the BRA, the DBRP unit soil poses a risk of 1.0 x 10 -6 for future workers in an
industrial land use scenario via ingestion of the soil in the top 2 foot layer. Analysis of the
risk evaluation indicated that calculated risks to future workers and residents under the
inhalation and ingestion of groundwater pathway were exaggerated because of conservative
assumptions in the modeling. The probable condition is that the DBRP source unit is not
contributing to groundwater contamination. As a result, no remedial action for the groundwater
with a period of continued monitoring for confirmation is the only appropriate action.

Institutional Controls (Alternative 2) for the DBRP Source Unit and no remedial action for the
groundwater with a period of confirmatory groundwater monitoring is the preferred action
at the DBRP because:

1) the groundwater history at the DBRP (summarized in Section V) indicates low frequency of
occurrences at low concentrations of gross alpha and total radium,

2) the DBRP soils do not represent a credible threat to the quality of groundwater in the
future.

A plan for continued annual groundwater monitoring, during the second quarter of each calendar
year, for the five wells at the DBRP will be included in the post-ROD document, the Corrective
Measures Implementation/Remedial Action Report (CMI/RAR). The groundwater samples will be
analyzed for following proposed list of constituents many of which have not been detected in the
groundwater at the DBRP since monitoring began in 1983.

arsenic
benzene
benzo(a)anthracene
benzo(a)pyrene
benzo(b)fluoranthene
benzo(k)fluoranthene
chromium
chrysene
1,2-dichloroethane
dichloromethane
endrine
manganese
octachlorodibenzo-p-dioxin
PCB-1260
total radium
1,1,2-trichloroethane
tritium
-------
The CMI/RAR will contain a detailed monitoring strategy which will outline the submittal
schedule and contents of the monitoring reports, which will include an analysis of the data, a
conclusion, and a recommendation. The recommendation section of the CMI/RAR will provide for
appropriate changes to the monitoring program with SCDHEC and EPA concurrence.
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Table 4. Summary of the Evaluation of Alternative 1 No Acton Under the Nine CERCLA Criteria

Alternative 1 No Action
Compliance with
ARARS
Implementability
Community
Acceptance
No actions taken
Will not reduce risks
from those reported
in the BRA.
PCB-1260 exceeds
the TEE guidance
1.0 mg/kg for
residential use.
Not applicable.
remediation
performed.
6 Ability to
construct and
operate the
technology
Not applicable.
action taken.
The site is in
compliance with all
location-specific
TBCs .
6 Compliance with
other criteria,
advisories, and
guidance
No action taken. Not
applicable.
Not applicable.
None destroyed or
treated.
performed.
6 Degree of
expected reduction
in toxicity, mobility,
and volume
No reduction in
toxicity, mobility, or
volume.
Not applicable.

6 Type and guantity
of residuals
remaining after
treatment
Not applicable.
Nothing is changed.
6 Time until
remedial action
obj ectives are
achieved
Not applicable.

6 Contaminants
Not applicable. No
technology applied.

6 Ease of
undertaking
additional remedial
action, if necessary
Very easy.
with
6 Coordination
and ability in
obtaining approvals
from other agencies
Not applicable. No
action taken.
6 Availability of
necessary eguipment
and specialists and
off-site services
Not applicable. No
action taken.
6 Availability of
prospective
technologies
Not applicable.
action taken.
(TBC=To be considered guidance)
No
6 Features of the
alternatives about
which the state has
reservations
Not applicable.
Not applicable. The
state has concurred
with Institutional
Controls.
6 Features of the
alternative about
which the community
has reservations
Not applicable.
6 Elements of the
alternative the
community strongly
opposes
Not applicable. The
community supports
Institutional Controls
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Table 5. Summary of the Evaluation of Alternative 2 Institutional Controls under the Nine CERCLA Criteria.

Alternative 2 Institutional Controls
Compliance with
ARARs
Implementability
Exceedes TBCs for
future residents only.
Precludes residential
use of this property.
DBRP complies with
industrial TEC
guidance 10-25
mg/kg
6 Compliance with
act ion-sped fie
ARARs

No action taken. Not
applicable.
The site is in
compliance with all
loc at ion-sped fie
guidance.
6 Compliance with
other criteria,
advisories, and
guidance
No action taken. Not
applicable.
6 Degree of
expected reduction
in toxicity, mobility,
and volume
No reduction in
toxicity, mobility, or
volume.
Not applicable.
6 Type and guantity
of residuals
remaining after
treatment
All contaninants
remain.
Not applicable.
remediation
performed.
Not applicable.
remediation.
performed.
6 Environmental
impacts
6 Time until
remedial action
obj ectives are
achieved
Not applicable.

6 Contaminants
6 Ability to
construct and
operate the
technology
Not applicable.
action taken.
6 Reliability of the
technology
6 Ease of
undertaking
additional remedial
action, if necessary
Very easy.
6 Coordination with
and ability in
obtaining approvals
from other agencies
Not applicable. No
action taken.
6 Availability of
necessary eguipment
and specialists and
off-site services
Not applicable. No
action taken.
6 Availability of
prospective
technologies
Not applicable. No
action taken.
Compliance with CAB recommendation for future industrial use of thf
6 Features of the
alternative about
which the state has
reservations
State supports
Institutional Controls.
6 Features of the
alternative the
community supports

Risks below 1x10 -4.
6 Features of the
alternative about
wh i c h the c ommu n i t y
has reservations
Community supports
Institutional Controls.

6 Elements of the
alternative the
community strongly
opposes
Community supports
Institutional Controls.
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Table 6. Summary of the Evaluation of Alternative 3 Native Soil Cover (4') under the Nine CERCLA Criteria.

Alternative 3 Native Soil Cover (4')
Compliance with
ARARs
Implementability
Community
Acceptance
Risk below 1x10 -4
Will meet PCB TEC
guidance for
residential 1 mg/kg.
6 Ability to
construct and
operate the
technology
Easy to install cover.
None applicable.
6 Compliance with
other criteria,
advisories and
guidance
Must comply with
OS HA.
Reliable unless
deed restrictions on
deep excavation are
not enforced.
6 Degree of
expected reduction
in toxicity, mobility,
and volume
No reduction in
toxicity or volume,
dust and leaching to
groundwater reduced.
6 Degree to which
treatment is
reversible

Cover is completely
reversible.
6 Type and guantity
of residuals
remaining after
treatment
All contaminants
remain.
Minor risk to workers
during installation
due to heavy
eguipment and dust.
6 Environmental
impacts
Potential impacts to
environmental from
heavy eguipment and
dust.
6 Time until
remedial action
obj ectives are
achieved
Cover can be
installed in <1 year.
6 Contaminants
Cover can be
breached. May be
difficult to prevent
deep excavation.
6 Ease of
undertaking
additional remedial
action, if necessary
Easy, additional
remediation may
reguire removal of
c o v e r .
6 Ability to monitor
effectiveness of the
remedy

Easy to monitor
effectiveness .
6 Coordination with
and ability in
obtaining approvals
from other agencies
Relatively easy to
obtain approval for
installing cover.
Rationale: ARARs are met.
PCB-1260 remains,
but cover provides a
barrier to exposure.
6 Availability of
necessary eguipment
and specialists and
off-site services
Easily available.
6 Availability of
prospective
technologies
Readily available.
Would allow restricted future residential use of property.
6 Features of the
alternative about
which the state has
reservations
Contaminants remain.
industrial use.
6 Features of the
alternative about
which the community
has reservations
Contaminants remain.
CAB recommended
future industrial use.

6 Elements of the
alternative the
community strongly
opposes
None.
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Table 7. Summary of the Evaluation of Alternative 4 Thermal Desorption/Incineration under the Nine CERCLA Criteria.

Alternative 4 Thermal Desorption/Incineration

Compliance with
ARARs
Implementability
Offers complete
protection of human
health and the
environment.
Will meet PCB TEC
for residential use 1
mg/kg.
6 Compliance with
other criteria,
advisories, and
guidance
Must comply with
OS HA.
Reliable unless
deed restrictions on
deep excavation are
not enforced.
6 Degree of
expected reduction
in toxicity, mobility,
and volume
Virtually complete.
6 Type and guantity
of residuals
remaining after
treatment
None .
Community will be
protected from off-
gas and dust by
engineering controls.
6 Protection of
workers during
remedial action

Manageable risk to
workers due to
eguipment, off-gas
and dust.
6 Environmental
impacts
Potential impacts to
environment from
eguipment, gas, and
dust.
6 Time until
remedial action
obj ectives are
achieved
Can be completed in
<1 year.
6 Contaminants
6 Ease of
undertaking
additional remedial
action, if necessary
Easy, no additional
remediation should
be reguired.
Easy to monitor
effectiveness .
6 Coordination with
and ability in
obtaining approvals
from other agencies
Air permits reguired.
6 Availability of
necessary eguipment
and specialists and
off-site services
Somewhat limited.
6 Availability of
prospective
technolgies
Somewhat limited.
Rationale: ARARs are met. Would allow future residential use of property with restrictions on excavation below
6 Features of the
alternative about
which the state has
reservations
None .
6 Features of the
alternative about
which the community
has reservations
CAB recommended
future industrial use .
High cost for alight
risk reduction.
6 Elements of the
alternative the
community strongly
opposes
None.
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Table 8. Summary of Evaluation of Alternative 5 Offsite Soil Disposal under the Nine CERCLA Cr

Alternative 5 Offsite Soil Disposal
Implementability
Will meet PCB TEC
guidance for

residential use, 1
mg/kg.
6 Compliance with
action-specific
ARARs
6 Compliance with
other criteria,
advisories, and
guidance
Must comply with
OSHA.
Reliable unless
deed restrictions on
deep excavation are
not enforced.
PCB contaminated
soil will be removed
and replaced with
clean fill.
6 Degree of
expected reduction
in toxicity, mobility,
and volume.
Virtually complete,
PCB is removed.
Community will be
protected from dust
Irreversible.
6 Type and guantity
of residuals
remaining after
treatment
None .
6 Environmental
impacts
Potential impacts to
environment from
eguipment and dust.
6 Time until
remedial action
obj ectives are
achieved
Can be completed in
six months.
6 Contaminants
6 Ease of
undertaking
additional remedial
action, if necessary
Easy, no additional
remediation should
be reguired.
6 Ability to monitor
effectiveness of the
remedy
Selected (YES/No): Yes
Easy to monitor
effectiveness.
6 Coordination with
and ability in
obtaining approvals
from other agencies
DOT regulations.
6 Availability of
necessary eguipment
and specialists and
off-site services
Readily available.
6 Availability of
prospective
technologies
Readily available.
Rationale: ARARs are met. Would allow future residential use of property with restrictions on excavation below 2 feet.
6 Features of the
alternative about
which the state has
reservations
None.
6 Features of the
alternative about
wh i c h the c ommu n i t y
has reservations
CAB recommended
future industrial use .
High cost for slight
risk reduction.
6 Elements of the
alternative the
community strongly
opposes
None.
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Implementation of this alternative will require both near- and long-term actions. For the near-
term, signs will be posted indicating that this area was used to manage hazardous materials.
In addition, existing SRS access controls will be used to maintain the use of this site for
industrial use only.

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 in compliance with Section 120(h) of
CERCLA. The deed will include notification disclosing former waste management and disposal
activities, results from groundwater monitoring, and remedial actions taken on the site. The
deed notification will in perpetuity, notify any potential purchaser that the property has been
used for the management and disposal of non-hazardous, inert construction debris, and that
wastes containing hazardous substances, such as degreasers and solvents, were also managed and
burned on the site.

The deed will also include deed restrictions precluding residential use of the property.
However, the need for these deed restrictions could be reevaluated at the time of 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, a survey plat of the area
will be prepared, certified by a professional land surveyor, and recorded with the appropriate
county recording agency.

The Institutional Controls Alternative is intended to be the final action for the DBRP Source
Unit. The solution is intended to be permanent and effective in both the long and near terms.
This alternative is considered to be the least cost option which is still protective of human
health and the environment.

Tbe 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 DBRP RFI/RI Report and the BRA, the DBRP source operable unit poses no significant
risk to the environment and minimal risk to human health. Therefore, a determination has been
made that Institutional Controls are sufficiently protective of human health and the environment
for the remaining contamination in the DBRP soils and groundwater.

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 random distribution and low levels of
contamination preclude a remedy in which treatment is a practical alternative. Institutional
Controls will result in hazardous substances, pollutants, or contaminants remaining in the waste
unit. Because treatment of the principal threats of the site was found to be impracticable, this
remedy does not satisfy the statutory preference for treatment as a principal element.

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 three
Parties, DOE, SCDHEC, and EPA, have determined that a Five Year Review of the ROD for the DBRP
will be performed to ensure continued protection of human health and the environment.

XI. Explanation of Significant Changes

The Statement of Basis/Proposed Plan 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 October 15. Comments that were received during the
45-day public comment period (September 17 through October 31, 1996) are addressed in Appendix A
of this Record of Decision and are available with the final RCRA permit.

The only changes to the remedy proposed for the DBRP in the Statement of Basis/Proposed Plan
(WSRC, 1996c) are: (1) that the probable condition is that no significant groundwater
contamination is originating in the DBRP and no remedial action for the groundwater with a
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period of continued monitoring for confirmation of no leaching to groundwater is the only
appropriate action, and (2) it was determined that it was not appropriate to append the
continued groundwater monitoring plan to the ROD as proposed in the Statement of Basis/Proposed
Plan. The plan for continued groundwater monitoring will be included in the CMI/RAR. In the
event that the probable condition is no longer appropriate, DOE will evaluate the need for
remedial action.

XII. Responsiveness Summary

There were three comments received during the public comment period. The Responsiveness Summary
(see Appendix A) of this Record of Decision addresses these comments.

XIII. Post-ROD Document Schedule

The post-ROD document schedule is listed below and is illustrated in Figure 4:

1. Corrective Measures Implementation/Remedial Action Report (CMI/RAR) Revision 0 for the DBRP
will be submitted for EPA and SCDHEC review four months after issuance of the ROD.

2. EPA and SCDHEC review of the DBRP CMI/RAR Revision 0 will last 90 days.

3. SRS revision of the DBRP CMI/RAR Revision 0 will be completed in 60 days after receipt of
all regulatory comments.

4. EPA and SCDHEC final review and approval of the DBRP CMI/RAR Revision 1 will last 30 days.

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XIV. REFERENCES

DOE (U. S. Department of Energy), 1994.
Public Involvement, A Plan for Savannah River Site. Savannah River Operations
Office, Aiken, South Carolina (1994).

DOE, 1996. 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, 1990. (U. S. Environmental Protection Agency). A Guide on Remedial Actions at
Superfund Sites with PCB Contamination. Office of Emergency and Remedial
Response. Directive 9355.4-01 FS (August 1990).

EPA, 1995. Supplemental Guidance to RAGS: Region 4 Bulletins; Development of Risk-
Based Remedial Options; Human Health Risk Assessment Bulletin No.5 (November 1995) .

Federal Facility Agreement 1993. Federal Facility Agreement for the Savannah River
Site, Administrative Docket No. 89-05-FF, (Effective Date: August 16, 1993).

WSRC (Westinghouse Savannah River Company), 1994. Data Summary Report for
the D-Area Burning/Rubble Pits. WSRC-RP-94-709, Rev. 0, Westinghouse Savannah
River Company, Aiken, South Carolina (1994).

WSRC, 1995a. Baseline Risk Assessment for the D-Area Burning/Rubble Pits (U)
WSRC-TR-94-708, Rev. 1, Westinghouse Savannah River Company, Aiken, South Carolina (1995)

WSRC, 1995b. RFI/RI Report for D-Area Burning/Rubble Pits (431-D and 431
ID)(U). WSRC-RP-94-707, Rev. 1, Westinghouse Savannah River Company
Aiken, South Carolina (1995).

WSRC, 1996a. F-Area Burning/Rubble Pits (231-F, 231-1F, and 231-2F) Corrective
Measures Study/Feasibility Study (U). WSRC-RP-95-660, Rev. 1, Westinghouse
Savannah River Company, Aiken, South Carolina (March 1996).

WSRC, 1996b. D-Area Burning/Rubble Pits (431-D and 431-1D) Corrective Measures
Study/Focused Feasibility Study (U). WSRC-RP-95-904, Rev. 1, Westinghouse
Savannah River Company, Aiken, South Carolina (March 1996).

WSRC, 1996c. Statement of Basis/Proposed Plan for the D-Area Burning/Rubble Pits
(431-D and 431-1D) (U). WSRC-RP-95 905, Rev. 1.3, Westinghouse Savannah
River Company, Aiken, South Carolina (August 1996) .
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Appendix A
Responsiveness Summary

The 45-day public comment period for the Statement of Basis/Proposed Plan for the D-Area
Burning/Rubble Pits (431-D and 431-1D)(U) began an September 17, 1996 and ended on October 31,
1996. A public meeting was held on October 15, 1996. Specific comments and responses are found
below. The comments are italicized and the responses are bolded.

Public Meeting Comments

The following comments were received during the Limited Action Proposed Plans/Permit
Modifications presentations. These comments were taken from the October 15, 1996 Public Meeting
as recorded in the Savannah River Site Information Exchange transcript.

Comment 1: Public Citizen: What risk is there for animals or I guess future environmental,
like if you were going to turn this into a park?

Response to Comment 1: As a part of the baseline risk assessment process for the DBRP, an
ecological risk assessment was conducted to assess the potential impacts to biota caused by
exposure to chemical and radiological constituents at the DBRP. A site ecological
reconnaissance survey was conducted in April 1994. No stressed vegetation was observed on or
around the DBRP. No threatened and endangered species were observed in the vicinity of the DBRP
or the adjacent ephemeral stream.

Based on the ecological risk assessment, there is little or no risk of adverse ecological
effects from the DBRP. Therefore, if the unit is turned into a park in the future, the animal
and plant species would not be affected.

Comment 2: Public Citizen: "Are you using like private landfills and private - or I guess
what other communities have developed? I mean it looks like a landfill to me. And it looks like
there are landfills all over the country and there's a whole lot of landfills that have been
turned into like parks and stuff. Is that an opportunity here to turn it into a park or to use
private models and maybe look at who has done this a lot? I guess the EPA guy was talking about
streamlining. Are you guys using private streamlining ideas?"

Response to Comment 2: There is a proposal for the entire Savannah River Site (SRS) to become a
national research park at some time in the future. Even now, the SRS is a national
environmental research park and as such, the site is/will be used for environmental research.
For the institutional control units, the only thing that our remedial decision has done is to
state that on this waste unit there will not be any residential use.

Due to its location, approximately 0.7 mile from the Savannah River and the absence of
remarkable scenery, the DBRP would be unlikely to become a recreational site. The risk levels
for the soils alone barely exceed the threshold for residential use; the presence of buried
waste should not interfere with the use of the DBRP as a park. However, there is groundwater
contamination at the DBRP that could preclude use of the local shallow groundwater as a source
of drinking water. Groundwater risk modeling indicates that there are constituents present which
could exceed primary drinking water standards in the future.

It should also be noted that the use of the DBRP as an environmental research or recreational
park would be evaluated at the time of property transfer if ownership of the land is ever
transferred from the Federal government. DBRP is one of the first burning/rubble pits at SRS to
be evaluated and will contribute to a streamlined process for characterization, technology
evaluation, and determining likely response actions at subsequent burning/rubble pits.

The following comment was received during the Formal Public Comment Session.

Comment 3: Mike Rourak: My name is Mike Rourak and my guestion is directed to Mr. Brian
Hennessey's earlier discussion (unintelligible) Silverton Road property, for example. In the
Future Use Manual that was sent out to some of us about the disposal of close to a million acres
of property for DOE, in your deed restrictions there's things that we cannot do. And we're
going to need a little bit before we can respond back to Washington. Those of us who received
the manual, we almost are going to need to know what those deed restrictions are because if we
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cannot have a subdivision then there's no need to bid the price accordingly or say that's what
we want to use it for. If we cannot graze cattle here like we do in Tennessee at
(unintelligible) or something or grow crops because we cannot put a well in for contamination,
then we are left with only looking at it for the pine trees.

So being federal, you own this property, Even with deed restrictions you've got to give us
either a Phase I, II, or III audit. In this case, it's the seller who has to provide this
liability, not necessarily the buyer's neglect of liability to due diligence. So it would
really help if we knew what deed restrictions would be there to a more extent and also what we
can use the land for. If I want to use it for applying 50 - - under the Code of Federal
Regulations 503, if I want to use it for bio solid disposal, can I do so? Because it's adjacent
to your other property. So the deed restrictions that you brought up were of immense concern
about responding back to the future use and the disposal of roughly 849,000 acres nationwide for
- to be put back into - I understand from Washington, they would like to put it back mainly into
public use to get the off of it. Maybe not so for the government, but for the local entities
who lose the tax base. Thank you.

Response to Comment 3: The SRS Future Use Project Report was distributed to inform citizens of
the planned future uses of the SRS. The recommendations that were presented in the report any
change over time and will be discussed with the stakeholders. Deed restrictions for federal
property are not determined until the land is transferred to non-federal control. At the time
of property transfer, the need for deed restrictions win be evaluated. Due to natural
attenuation, decay, etc, the conditions at specific areas may not warrant any deed restrictions.
All legal requirements will be met at the time of property transfer.
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