Superfund Record of Decision Savannah River Site USDOE Operable Unit 4 Aiken SC


                                    EPA/ROD/R04-97/024
                                    1997
EPA Superfund
     Record of Decision:
     SAVANNAH RIVER SITE (USDOE)
     EPA ID: SC1890008989
     OU04
     AIKEN, SC
     03/27/1997

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DECLARATION FOR THE RECORD OF DECISION

Unit Name and Location

Gunsite 720 Rubble Pit Unit
(SRS Building 631-16G)
Savannah River Site
Aiken, South Carolina

The Gunsite 720 Rubble Pit Unit (631-16G) is listed as a Resource Conservation and Recovery Act
(RCRA) 3004(u) Solid Waste Management Unit/Comprehensive Environmental Response, Compensation,
and Liability Act (CERCIA) 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 action for the Gunsite 720 Rubble Pit Unit
located at the Savannah River Site near Aiken, South Carolina. The selected action was
developed in accordance with CERCLA, as amended, and to the extent practicable, the National Oil
and Hazardous Substances Pollution Contingency Plan (NCP). The selected remedy satisfies both
CERCLA and RCRA 3004 (u) reguirements. This decision is based on the Administrative Record File
for this specific RCRA/CERCLA Unit.

Description of the Selected Remedy

The results of the Resource Conservation and Recovery Act Facility Investigation/Comprehensive
Environmental Response, Compensation, and Liability Act Remedial Investigation, indicate that
the Gunsite 720 Rubble Pit Unit poses no risk to human health or the environment. Therefore, no
action is needed at the Gunsite 720 Rubble Pit Unit. This is the final RCRA/CERCLA action for
the Gunsite 720 Rubble Pit Unit. The South Carolina Department of Health and Environmental
Control has modified the SRS RCRA permit to incorporate the selected remedy.

Declaration Statement

Based on the results of the remedial investigation, no action is necessary at the Gunsite 720
Rubble Pit Unit to ensure the protection of human health and the environment. Since the Gunsite
720 Rubble Pit Unit poses no threat to human health or the environment, and no action is needed,
the CERCLA Section 121 reguirements are not applicable. This action is protective of human
health and the environment and is meant to be a permanent solution, final action, for the
Gunsite 720 Rubble Pit Unit. No five-year remedy review is needed or will be performed.

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                  DECISION SUMMARY
          REMEDIAL ALTERNATIVE SELECTION  (U)
         The Gunsite 720 Rubble Pit  (631-16G)
             Operible Unit:  Final Action
                   WSRC-RP-96-00832
                      Revision 1
                     January 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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                    Table of Contents

SECTION

I.     Site and Operable Unit Names, Locations,
       and Descriptions 	 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 Characteristics 	 6
VI.    Summary of Operable Unit Risks	7
VII.    Description of the No Action Alternative	 8
VIII.  References	9

List of Figures

1.  Location of the Gunsite 720 Rubble Pit Unit in Relation to
    Major SRS Facilities	2

2.  Layout of the Gunsite 720 Rubble Pit Unit Showing Sample
    Locations and Location and Concentration of Metals which
    Exceed the Unit-Specific Background Level 	 3

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

Introduction

The Savannah River Site (SRS) occupies approximately 803 square kilometers (310 square miles) of
land adjacent to the Savannah River, principally in Aiken and Barnwell Counties of South
Carolina. SRS is a secured U.S. qovernment facility with no permanent residents. SRS is
located approximately 40 kilometers (25 miles) southeast of Auqusta, GA and 32 kilometers (20
miles) south of Aiken, SC. Fiqure 1 shows the location of the Gunsite 720 Rubble Pit Unit in
relation to other facilities at SRS.

SRS is owned by the Department of Enerqy (DOE). Manaqement and operatinq services are provided
by Westinqhouse Savannah River Company (WSRC). SRS has historically produced tritium,
plutonium, and other special nuclear materials for national defense. SRS has also provided
nuclear materials for the space proqram and for medical, industrial, and research efforts.
Chemical and radioactive wastes are byproducts of nuclear material production processes.

The Federal Facility Aqreement (FFA, 1993) for SRS lists the Gunsite 720 Rubble Pit Unit
(631-16G) as a RCRA/CERCLA Unit that required further evaluation. An investiqation/assessment
process that inteqrates and combines the RCRA Facility Investiqation (RFI) with the CERCLA
Remedial Investiqation (RI) to determine the actual or potential impact to human health and the
environment was performed.

The Gunsite 720 Rubble Pit Unit is located within SRS and is approximately 305 meters (1000
feet) west of South Carolina Hiqhway 125, 168 meters (550 feet) north of SRS Road A-2, and 2.5
kilometers (1.5 miles) from the nearest SRS boundary (see Fiqure 1).

The topoqraphy of the area is relatively flat with an elevation of about 95.7 meters (150 feet)
above mean sea level. The unit consists of an open area covered with natural shrub qrowth and
surrounded by native pine trees. The unit encompasses an area of approximately 2,250 square
meters, (25,000 square feet). Two concrete slabs and an old well are located on the east side
of the unit (see Fiqure 2). Surface drainaqe in the area is to Upper Three Runs Creek,
approximately 1,200 meters (4000 feet) south of the unit. The water table in the area is
approximately 10 feet below qround surface.

Section II. Operable Unit History and Compliance History

Operable Unit History

Durinq the period from 1955 to 1960, to defend SRS in the event of an air attack, the U.S. Army
established onsite anti-aircraft artillery qun emplacements at several locations near the
perimeter of SRS. The Gunsite 720 was one of those emplacements. There is no documentation or
record of any hazardous substance manaqement or disposal at this unit. There is no evidence
that any recent disposal activity has occurred. Also, them is no evidence of any burninq or
excavation at this waste unit.

In the early to mid 1980s, while work was beinq performed in the area, nine (9) empty, partially
buried drums, labeled "duPont Freon 11", were found at the qunsite. The drums were excavated in
July 1987, and placed on a pallet at the qunsite. The area around the drums was screened durinq
excavation and the liquid (rainwater) that collected in the excavated drums was sampled prior to
disposal. No evidence of hazardous substances was found. In October 1989, the drums were
removed from the unit. A review of SRS plans and maps indicated that an underqround fuel
storaqe tank was at the qunsite. An above-qround tank was also noted on the maps. However,
there is no physical evidence that the tanks still exists at this unit. No contamination, other
than household trash (bottles, wrappers, etc.), was noted in the area. Currently, the unit
consists of two concrete slabs and an old well.

Compliance History

At SRS, certain waste materials are manaqed in accordance with the requirements of the Resource

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Conservation and Recovery Act  (RCRA).   To comply with the requirements of RCRA, certain SRS
activities have required treatment, storaqe, or disposal, closure or post closure RCRA permits.

Non-requlated units, called solid waste manaqement units  (SWMU),  include any activity where
hazardous constituents may remain uncontrolled and may potentially release to the environment.
Investiqation and potential corrective action for these SWMU(s) are mandated under RCRA 3004(u).

In 1995, SRS received a hazardous waste permit from the South Carolina Department of Health and
Environmental Control (SCDHEC, which includes corrective action requirements.  Specifically,
Part V of the permit mandates that SRS establish and implement a RCRA Facility Investiqation
(RFI) proqram to fulfill the requirements specified in Section 3004(u).

Hazardous substances, as defined by CERCLA, are also present in the environment at SRS.  On
December 21, 1989, SRS was placed on the National Priorities List  (NPL).   A site placed on the
NPL comes under the requirements of CERCLA.  In accordance with Section 120 of CERCLA, DOE has
entered into an FFA with EPA and SCDHEC to coordinate cleanup activities at SRS into one
comprehensive strateqy that fulfills RCRA Section 3004(u) and CERCLA assessment, investiqation,
and response action requirements.

The remedial investiqation for the Gunsite 720 Rubble Pit Unit was conducted from March 1988 to
early 1993.  The results of the RFI/RI Report completed in 1996 (WSRC, 1996a) indicate that the
Gunsite 720 Rubble Pit Unit poses no current or future risk to human health or the environment.
Therefore, no action is warranted.

Accordinq to EPA quidance, if there is no current or potential risk to human health and the
environment and no action is warranted, the CERCLA 121 requirements are not triqqered.  This
means that there is no need to evaluate other alternatives.

To fulfill the public participation requirements of CERCLA, RCRA,  and the South Carolina
Hazardous Waste Manaqement Requlations (SCHWMR), a Statement of Basis/Proposed Plan (WSRC,
1996b) presentinq the no action alternative and the rational for selectinq the alternative was
prepared and submitted for public comment.  The public was provided an opportunity to
participate in the remedy selection process and was stronqly encouraqed to submit comments  (see
Section III).  Followinq the public comment period, all the comments submitted were reviewed and
considered.  DOE, in consultation with EPA-Reqion IV and SCDHEC,  selected the final action for
the Gunsite 720 Rubble Pit Unit.  Final selection of the remedial alternative satisfies FFA
requirements.  SCDHEC has modified the SRS RCRA permit to incorporate the selected remedy.

Section III.  Highlights of Community Participation

Public participation requirements are listed in CERCLA Sections 113 and 117.  These requirements
include the establishment of an Administrative Record File that documents the selection of
remedial alternatives and allows for review and comments by the public reqardinq those
alternatives.  The Administrative Record File must be established "at or near the facility at
issue".  The SRS Public Involvement Plan  (DOE, 1994)  is desiqned to facilitate public
involvement in the decision-makinq process for permittinq, closure, and the selection of
remedial alternatives.  Section 117 (a) of CERCLA requires publication of a notice of any
proposed remedial action and provides the public an opportunity to participate in the selection
of a remedial action.  The Statement of Basis/Proposed Plan for the Gunsite 720 Rubble Pit Unit,
which is part of the Administrative Record File, hiqhliqhts the aspects of the investiqation and
identifies the preferred action for addressinq the Gunsite 720 Rubble Pit Unit.

RCRA provides opportunities for the public to comment on draft permit modifications. Public
participation requirements are also listed in SCHWMR R.61-79.124 and require publication of the
draft permit modifications.  SCHWMR R.61-79.124 requires a brief description and response to all
siqnificant comments be made available to the public as a part of the Administrative Record.
The preferred alternative proposed in the Statement of Basis/Proposed Plan was also proposed as
a draft permit modification under RCRA.  Therefore, any comments received on the Statement of
Basis/Proposed Plan wore also applicable to the draft RCRA permit modification, proposinq the
same remedy for the Gunsite 720 Rubble Pit Unit.

The Administrative Record File, which contains the Statement of Basis/Proposed Plan and all the
documents  (unabridqed) listed in the reference section of this document,  is available at the EPA

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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, SC 29801
(803) 641-3465

Thomas Cooper Library
Government Documents Department
University of South Carolina
Columbia, SC 29208
(803) 777-4866

Similar information is available through the repositories listed below:

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

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

The public was notified of a public comment period by mailing the SRS Environmental Bulletin, a
newsletter sent to approximately 3500 citizens in South Carolina and Georgia, and through the
Aiken Standard, the Allendale Citizen Leader, the Barnwell People-Sentinel, the State, and the
Augusta Chronicle newspapers.  The public comment period was also announced on local radio
stations. The 45-day public comment period began on September 17, 1996 and ended on October 31,
1996.  No public comments were received.

Section IV.    Scope and Role of Operable Unit within the Site Strategy

The overall strategy for addressing the Gunsite 720 Rubble Pit Operable Unit was to:  (1)
determine if there had been a release of hazardous substances; (2)  determine the nature and
extent of any contamination;  (3) perform a baseline risk assessment; and  (4) evaluate the need
for remedial action to address any potential risks to human health and the environment.

The investigation and risk assessment have been completed for the Gunsite 720 Rubble Pit Unit.
Since the results of the investigation indicate that the unit poses no risk to human health or
the environment, no action was recommended.

The field investigations and soil sampling conducted during 1990 and 1993 also indicate that
there are no hazardous substances at the Gunsite 720 Rubble Pit Unit that would impact the
groundwater.

The Gunsite 720 Rubble Pit Unit is an operable unit located within the Upper Three Runs Creek
watershed.  All the source control and groundwater operable units located within this watershed
will be evaluated to determine their impacts, if any, to the associated streams and wetlands.

SRS will manage all source control units to prevent impact to the watershed.  Upon disposition
of all source control and groundwater operable units within this watershed, a final
comprehensive ROD for the Upper Three Runs Creek watershed will be pursued.

Section V.  Summary of Operable Unit Characteristics

The Gunsite 720 Rubble Pit Unit was one of the anti-aircraft artillery gun emplacements the U.S.

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Army established at several locations near the perimeter of SRS. There is no documentation or
record of any hazardous substance management or disposal at this unit. There is no evidence
that any recent disposal activity has occurred. Also, there is no evidence of any burning or
excavation at this waste unit.

Media Assessment

The RFI/RI Work Plan (WSRC, 1990) and RFI/RI Report (WSRC, 1996a) contain detailed information
and analytical data for all the investigations conducted and samples taken in the media
assessment of the Gunsite 720 Rubble Pit Unit. These documents are part of the Administrative
Record File. The results of the RFI/RI Report are summarized below.

In 1986, a magnetic survey was conducted to locate underground tank(s) believed to be
buried at the unit. However, the results of the magnetometer survey were inconclusive.

In March 1988, four soil gas samples were analyzed for chlorinated hydrocarbons. No chlorinated
hydrocarbons (chlorinated solvents) were detected.

In March 1989, a ground penetrating radar survey was also conducted. The survey indicated that
there were no buried or underground objects in the area. Trenches were also excavated at the
unit to visually characterize buried waste and to locate and identify any underground storage
tanks that might be present (see Figure 2). No evidence of burial pits was found. No trenches
were backfilled with the excavated materials and leveled.

Soils

During 1990, 12 soil samples were obtained from various locations and depth intervals within the
Gunsite 720 Rubble Pit Unit area and at one background location(see Figure 2). The
concentrations detected for al] the hazardous substances were below their respective EPA
risk-based concentration levels.

In early 1993, SCDHEC expressed some concerns regarding the existence of the underground storage
tanks at the unit and potential releases from the tanks and the drums that were located at the
Gunsite 720 Rubble Pit Unit. SRS performed additional ground penetrating radar and magnetometer
surveys, and also obtained additional soil samples from the areas where the drums had been found
and the underground storage tank was believed to have been located. Samples were collected at
various depths ranging from 1.2 meters (4 feet) down to 5.5 meters (18 feet). Figure 2 shows
the locations of samples collected in the 1993 survey.

The ground penetrating radar and magnetometer surveys did not indicate the existence of an
underground storage tank or any other buried debris. It was concluded that the tank had been
removed.

No hazardous substances were detected in the underground storage tank area. In the drum area
also, the maximum concentration of all the hazardous substances detected (except for chromium)
were lower than the maximum concentrations found in the 1990 sampling. Hence, the only metal
detected in 1993 sampling exceeding the 1990 maximum concentration was chromium. However, the
concentration was significantly less than EPA risk-based concentrations for chromium (Cr +6 and
Cr +3).

Based on comparison of analytical results to risk-based concentrations and two times unit
specific concentrations, it was evident that there had been no environmental impact due to
hazardous substance disposal at or release from the Gunsite 720 Rubble Pit Unit.

Groundwater

Since preliminary investigations conducted in 1988 and soil samples collected in 1990 and 1993
concluded that there was no evidence of contamination, no groundwater investigations were
conducted.

Surface Water/Sediment

No surface water or sediment sampling was conducted because the nearest surface water feature

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(the Upper Three Runs Creek) is located approximately 1.2 kilometers (3/4-mile) from the Gunsite
720 Rubble Pit Unit.

Section VI. Summary of Operable Unit Risks

Human Health Risks

As part of the RCRA/CERCIA process for the Gunsite 720 Rubble Pit Unit, a risk assessment was
performed using data generated during the assessment phase. Detailed information regarding the
development of constituents of potential concern, fate and transport of contaminants and risk
assessment can be found in the RFI/RI Report for the Gunsite 720 Rubble Pit Unit (631-16G) (U),
WSRC-RP-95-360, Rev. 1 (WSRC, 1996) .

After combining analytical data and eliminating those analytes; not detected in any samples, the
data were evaluated on the basis of quality with respect to sample guantitation limits,
frequency of detection, relative toxic potential of the constituent, laboratory qualifiers and
codes, and blanks. The remaining data (constituents detected) were compared to two times the
unit-specific background and EPA developed Risk-Based Concentrations (RBCs).

RBCs developed by EPA Region III (EPA, 1995) were used to screen the constituents of potential
concern for the Gunsite 720 Rubble Pit Unit. This guidance provides reference doses and
carcinogenic potency data for nearly 600 chemicals. These toxicity constants have been combined
with "standard" exposure scenarios to calculate RBCs (i.e., chemical concentrations
corresponding to fixed levels of risk; a hazard quotient of 1, or a lifetime cancer risk of one
in one million). The RBCs are very similar to preliminary remediation goals which are
concentration goals for individual chemicals for a specific medium and land use combinations at
CERCLA Units.

Following the comparison to background and RBCs, it was concluded that the concentrations of all
hazardous materials analyzed were below any EPA risk-based concentration action levels. Hence,
there are no constituents of potential concern for evaluation in a CERCLA baseline risk
assessment (BRA), and there is no determinable risk associated with the Gunsite 720 Rubble Pit
Unit.

Current Land Use

Since there is no current activity at the Gunsite 720 Rubble Pit Unit the current land use
scenario is not applicable.

Future Land Use

Since there is no constituents of concern and no determinable risk associated with the Gunsite
720 Rubble Pit Unit, the future land use scenario is not applicable.

Ecological Risks

Based on the physical and analytical data pertaining to this unit, there is no evidence that
waste materials were managed or disposed of at the Gunsite 720 Rubble Pit Unit. Therefore, it
is reasonable to conclude that this unit presents no significant ecological risk.

Section VII. Description of the No Action Alternative

Based on the unit characterization and risk assessment, the Gunsite 720 Rubble Pit Unit poses no
risk to human health and the environment. Therefore, the unit requires no cleanup activities
and the no action alternative is recommended for this unit. No additional alternatives were
considered for evaluation.

The no action alternative means that no remedial action will be performed at the Gunsite 720
Rubble Pit Unit. There is no waste to treat, no institutional or engineering controls are
required, and there are no applicable or relevant and appropriate requirements (ARARs). Because
no further action would be taken, the Gunsite 720 Rubble Pit Unit would remain in its present
condition. No costs will be involved for this action.

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Since the Gunsite 720 Rubble Pit quit poses no risk to human health or the environment and no
action is warranted at this unit, the CERCLA Section 121 requirements are not applicable.  The
no action alternative will be the final action for the Gunsite 720 Rubble Pit Unit and there
will be no five-year  (ROD) reviews.  This solution is meant to be permanent and effective in
both the lonq and short term, and protective of human health and the environment.

Section VIII.  References

DOE  (U.S. Department of Enerqy), 1994,
Public Involvement, A Plan for the
Savannah River Site, Savannah River
Operations Office, Aiken, SC.

EPA  (U.S. Environmental Protection
Aqency),  1995, Risk-Based Concentration
Table, EPA-III, January-June 1995, dated
March 7,  1995.

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

WSRC, 1990, RCRA Facility
Investiqation/Remedial Investiqation Plan
for the Gunsite 720 Rubble Pit Unit,
WSRC-RP-90-1049, Westinqhouse
Savannah River Company, Aiken, SC.

WSRC, 1996a, RCRA Facility
Investiqation/Remedial Investiqation Report
for the Gunsite 720 Rubble Pit Unit  (631-
16G)  (U), WSRC-RP-95-360, Rev. 1,
Westinqhouse Savannah River Company,
Aiken, SC.

WSRC, 1996b, Statement of
Basis/Proposed Plan for the Gunsite 720
Rubble Pit Unit (631-16G) (U), WSRC
RP-96-217, Rev. 1, Westinqhouse
Savannah River Company, Aiken, SC.

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