final ou 1 esd - adminrec · awaiting recoupment at the osa between 1977 and 1980. in 1984, the...

Final

EXPLANATION OF SIGNIFICANT DIFFERENCES OU 1 OPEN STORAGE AREA

DEFENSE GENERAL SUPPLY CENTER RICHMOND, VIRGINIA

Prepared by:

Defense Logistics Agency

Environment and Safety (DES-E)

8725 John J. Kingman Road, Suite 2639

Fort Belvoir, VA 22060-6221

and

Defense Supply Center Richmond

8000 Jefferson Davis Highway

Richmond, VA 23297-5000

June 2007

Final ESD, Operable Unit 1 Defense Supply Center Richmond, Virginia June 2007

i

TABLE OF CONTENTS

1.0 INTRODUCTION........................................................................................................... 1-1

1.1 SITE NAME AND LOCATION AND ADMINISTRATIVE RECORD.............. 1-1

1.2 IDENTIFICATION OF LEAD AND SUPPORT AGENCIES ............................. 1-1

1.3 RATIONALE FOR ESD ........................................................................................... 1-1

1.4 AUTHORIZING SIGNATURES ............................................................................. 1-4

2.0 SITE HISTORY, CONTAMINATION, AND SELECTED REMEDY ........................ 2-1

2.1 SITE HISTORY......................................................................................................... 2-1

2.2 SITE CONTAMINATION........................................................................................ 2-1

2.3 DESCRIPTION OF SELECTED REMEDY .......................................................... 2-3

3.0 DOCUMENT BASIS ...................................................................................................... 3-1

3.1 RATIONALE FOR SIGNIFICANT DIFFERENCES........................................... 3-1

3.2 DESCRIPTION OF SIGNIFICANT DIFFERENCES .......................................... 3-1

3.3 SUPPORT AGENCY COMMENTS AND PUBLIC PARTICIPATION ............ 3-1

3.4 STATUTORY DETERMINATION......................................................................... 3-1

4.0 REFERENCES ............................................................................................................... 4-1

FIGURES

Figure 1-1 - Zone Locations and Operable Units, DSCR, Virginia............................................. 1-2

Figure 2-1 - Recent Photo of OU 1 Showing Compressed Gas Cylinder Storage ...................... 2-2


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ACRONYMS AND ABBREVIATIONS

ARAR Applicable or Relevant and Appropriate Requirements

CERCLA Comprehensive Environmental Response, Compensation and Liability Act

COPC Chemical of Potential Concern

DGSC Defense General Supply Center

DLA Defense Logistics Agency (DLA)

DSCR Defense Supply Center Richmond (DSCR)

ESD Explanation of Significant Differences

FFA Federal Facility Agreement

HHBRA Human Health Baseline Risk Assessment

IC Institutional Controls

NCP National Oil and Hazardous Substances Contingency Plan

NPL National Priority List

OSA Open Storage Area

OU Operable Unit

PAH Polynuclear Aromatic Hydrocarbons

RAO Remedial Action Objectives

RBC Risk-based Criteria

RI Remedial Investigation

ROD Record of Decision

SVOC Semi-volatile Organic Compound

TCE Trichloroethene

USEPA United States Environmental Protection Agency

VDEQ Virginia Department of Environmental Quality

VOC Volatile Organic Compound


1-1

1.0 INTRODUCTION

1.1 SITE NAME AND LOCATION AND ADMINISTRATIVE RECORD

The site is known as Operable Unit (OU) 1, Open Storage Area (OSA) Source Area Contaminated Soils,

located within the Defense Supply Center Richmond (DSCR) (formerly known as Defense General

Supply Center [DGSC]) in Chesterfield County, Virginia. Figure 1-1 shows the site location within

DSCR. The underlying site groundwater is being addressed as part of another site known as OU 6,

OSA/Area 50/National Guard Area Groundwater. Feasibility study activities are currently ongoing for

OU 6.

This Explanation of Significant Differences (ESD) was prepared in accordance with Section 117(c) of the

Comprehensive Environmental Response, Compensation and Liability Act (CERCLA), as amended, and

Section 300.435(c)(2)(i) of the National Oil and Hazardous Substances Pollution Contingency Plan

(NCP). It will become part of the Administrative Record file for OU1 in accordance with the NCP at 40

CFR Section 300.825(a)(2). The Administrative Record for all DSCR sites is maintained at the

Chesterfield Public Library, Central Branch, Local History Department, located at 9501 Lori Road,

Chesterfield, Virginia 23832 (phone number: (804) 748-1603). The Administrative Record is also

available at www.adminrec.com/dla.asp.

1.2 IDENTIFICATION OF LEAD AND SUPPORT AGENCIES

The Defense Logistics Agency (DLA) is the Lead Agency (as defined in the NCP at 40 CFR Section

300.5) for OU 1. The United States Environmental Protection Agency (USEPA) Region III is the lead

regulatory agency and the Virginia Department of Environmental Quality (VDEQ) is the support agency.

In accordance with the 1990 Federal Facility Agreement (FFA) between DLA and USEPA regarding

implementation of CERCLA at DSCR, the USEPA and VDEQ review and comment on draft documents

and decisions. Site remedial response decisions and actions are jointly issued by DLA and USEPA, with

the concurrence of VDEQ.

1.3 RATIONALE FOR ESD

The NCP at 40 CFR Section 300.435(c)(2)(i) requires the Lead Agency to publish an ESD when a

remedial action will differ significantly from the final remedy selected and described in the Record of

Decision (ROD) with respect to scope, performance, or cost.


1-2

Figure 1-1 - Zone Locations and Operable Units, DSCR, Virginia


1-3

The ROD for OU 1 was signed by DLA in April 1992 and by the USEPA Region III in May 1992, with

concurrence from the VDEQ. For two instances, in paragraph 1.2 of the ROD, the remedy is termed as an

“interim” remedy. However, in no other instance in the Proposed Plan for OU 1 nor in the ROD,

including the cover page, is the remedy described as “interim.” This ESD documents that the use of the

term “interim” in the 1992 OU 1 ROD, when describing the remedy, was a typographical error and

declares that the 1992 ROD is the final ROD for OU 1.

The selected remedial action for contaminated soils includes institutional controls (ICs) restricting access

to OU 1 and continued industrial operations within the secured OSA. The ICs, consisting of continued

industrial uses and restricted site access, function to reduce direct contact with semi-volatile organic

compounds (SVOCs) and metals in site soil. The site conditions and remedy have been reviewed every

five years in accordance with CERCLA Section 121 (c) and the NCP at 40 CFR Section 300.430

(f)(4)(ii).

Comprehensive CERCLA five-year reviews conducted for DSCR sites in 1997 and in 2003 determined

that the remedy in place at OU 1 is functioning as designed and protective of human health by restricting

direct contact with soils. Nevertheless, the 2003 CERCLA five-year review concluded that human health

risks associated with indoor vapor intrusion from low levels of volatile organic compounds (VOCs) in

soil should be evaluated, along with the potential for continued leaching of soil VOCs to groundwater and

the impact to groundwater quality. Chemical leaching and impact to groundwater quality is being

addressed in the feasibility study for OU 6.

The December 2006 Revised Human Health Baseline Risk Assessment (HHBRA) for OU 1 determined

that the potential risks to any future indoor workers who might inhale vapors emanating from VOCs in

underlying soils were within the acceptable risk values pursuant to the NCP at 40 CFR 300.430

(e)(2)(i)(A). Therefore, the selected remedial action taken at OU 1 continues to be protective of human

health against risks from direct contact and indoor vapor intrusion.


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1.4 AUTHORIZING SIGNATURES

_____________________________ Date: ___________________

CHARLES R. CARRELL

Director, DES Richmond

Defense Supply Center Richmond (DSCR)

_____________________________ Date: __________________

DENNIS LILLO

Staff Director, Environmental, Safety, and Occupational Health

HQ, Defense Logistics Agency (DLA)

_____________________________ Date: ___________________

JAMES J. BURKE

Director, Hazardous Site Cleanup Division

United States Environmental Protection Agency (USEPA)

Region III

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2.0 SITE HISTORY, CONTAMINATION, AND SELECTED REMEDY

2.1 SITE HISTORY

Since the opening of DSCR in 1942, the 43-acre OSA (which includes OSAs 38 through 47) has been

used for storage of drummed and containerized chemicals (DLA 2003). More recently, the OSA has been

used for storage of compressed gas cylinders as shown in Figure 2-1. With the exception of pathways

between stored containers, the OSA is not paved, and drums and containers are stored directly on the

ground or on wooden skids. Spills and leaks have occurred in the past in this area (DLA 1992).

The northern end of OSAs 39 and 40 was the site of former drum recoupment activities carried out

between the early 1960s and the late 1970s. Drum recoupment involved transferring contents of leaking

drums into new or reclaimed containers. As such, the soils where recoupment occurred are stained from

past releases from leaky drums. Three documented spills of malathion occurred from 55-gallon drums

awaiting recoupment at the OSA between 1977 and 1980.

In 1984, the USEPA proposed that DSCR be placed on the CERCLA National Priorities List (NPL), and

in 1987, the installation appeared on the published NPL. A remedial investigation (RI) was completed for

the OSA/Area 50/National Guard Area in July 1989. DLA entered into an FFA with USEPA in 1990

regarding implementation of CERCLA at DSCR, and a proposed plan for OU 1 OSA source area soils

was released to the public on January 20, 1992. After a public comment period, DLA and USEPA

Region III signed the ROD in May 1992, which required ICs restricting human contact with chemicals in

the OSA source area soils.

2.2 SITE CONTAMINATION

From the historical RI data and more recent sampling events in 1998 and 2002, the 2006 Revised

HHBRA identified the following OU 1 soil chemicals of potential concern (COPCs):

• Arsenic

• Iron

• Thallium

• Polynuclear aromatic hydrocarbons (PAHs), including benzo(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, dibenz(a,h)anthracene, and naphthalene

• Chloroform

• Trichloroethene (TCE)


2-2

Figure 2-1 - Recent Photo of OU 1 Showing Compressed Gas Cylinder Storage


2-3

Although pesticides were detected in the 1988 RI and the more recent 1998 and 2002 sampling rounds,

their concentrations were below the USEPA Region III industrial risk-based criteria (RBCs). Of these

COPCs, arsenic and PAHs are the chemicals of concern potentially affecting human health due to toxicity

and concentration.

Assuming no institutional controls restricting human exposure, the estimated site-related carcinogenic risk

to industrial workers is above the NCP’s threshold value of 1 x 10-6 (DLA 1992 and DLA 2006) but

below 1 x 10-4, the departure value for action. However, the risks posed by potential indoor vapor

intrusion are below the threshold values (DLA 2006). According to the 1992 ROD and subsequent

CERCLA five-year reviews, the levels of soil chemicals do not pose an ecological risk to the

environment.

2.3 DESCRIPTION OF SELECTED REMEDY

Remedial action objectives (RAOs) for OU 1 are:

• Reduce or eliminate human contact with the contaminated media through the use of physical controls

• Comply with Applicable or Relevant and Appropriate Requirements (ARARs) and administrative requirements

• Continue operation of the site as a restricted area.

Ecological risks posed by the site to the environment were determined to be small and warranting no

action because of the low levels of contaminants present (DLA 1992).

The selected remedy described in the 1992 ROD consists of the following major components (DLA

1992):

• Continued operation of the site as a restricted industrial area in which access to the site is controlled

by a duel system of fences and gates. Security personnel also restrict access to the fenced area.

• ICs restricting future development and use of the area. Restrictions include limitations on the transfer

of the property, maintenance protocol, environmental sampling prior to the start of any construction at

the area, and ambient air testing and personnel monitoring during the construction phase.

Because hazardous substances remain in place at OU 1 above levels considered safe for unlimited site use

and unrestricted exposure, five-year reviews of the remedy have been conducted in accordance with

CERCLA Section 121 (c) and the NCP (40 CFR Section 300.430(f)(4)(ii)). The five-year reviews have


2-4

confirmed and will continue to evaluate the effectiveness of the ICs until such time as OU 1 site

conditions are declared suitable for unlimited use and unrestricted exposure, or the statutory requirement

for periodic performance reviews is met. The remedy in place at OU 1 has been reviewed in 1997 and

again in 2003, with the subsequent 2006 Revised HHBRA finding that the remedy continues to be

protective of human health.


3-1

3.0 DOCUMENT BASIS

3.1 RATIONALE FOR SIGNIFICANT DIFFERENCES

The rationale for issuing an ESD to correct the typographical error in the 1992 ROD, and thereby to

clarify that the 1992 ROD selects the final remedy for OU 1, is that the typographical error could have led

to a mistaken expectation that the 1992 ROD was an interim remedy only, and that a final remedy is still

required for OU 1. The Proposed Plan for the OU 1 ROD, presented to the public in January 1992, and

upon which public comments were solicited for the site, did not describe the remedy as “interim.”

Moreover, the 1992 ROD itself describes the remedy selected as a “remedy” or “remedial action” without

the qualifier “interim” a total of 33 times. The term “interim” was used in the ROD only twice, and both

times in the same paragraph. There are no documents made at the time the 1992 ROD was issued to

indicate that the remedy selected in the ROD was not intended to be a final remedy for the operable unit.

Thus, it is concluded by DLA and USEPA that the term “interim” in Section 1.2 of the ROD was merely

a typographical error.

3.2 DESCRIPTION OF SIGNIFICANT DIFFERENCES

This ESD clarifies that the 1992 ROD for OU 1 at DSCR selected a final remedy for the site. The only

difference between the ROD as issued in 1992 and the change embodied in this ESD is removal of the

word “interim” at two instances in Section 1.2 of the Declaration of the 1992 ROD. This difference could

amend the expectation of the public that a final ROD is yet to be issued at the site. There is no expected

change in outcome for the site.

3.3 SUPPORT AGENCY COMMENTS AND PUBLIC PARTICIPATION

USEPA Region III and the VDEQ were consulted on the change from interim to final designation for this

remedy at OU 1. USEPA issues this ESD with DLA; VDEQ concurs with the action. This ESD meets

the public participation requirements set forth in the NCP in 40 CFR 300.435(c)(2)(i).

3.4 STATUTORY DETERMINATION

The 1992 ROD for OU 1, as clarified by this ESD, satisfies the requirements of CERCLA Section 121

regarding cleanup standards.


4-1

4.0 REFERENCES

Defense Logistics Agency (DLA), 1989. Interim Guidance for Construction Site Clearance at U.S. Army Installations. December 27.

DLA, 1992. Final Record of Decision for OU1—Open Storage Area, Defense General Supply Center, Richmond, Virginia. April.

DLA, 1997. Final Five-Year Review Report for Operable Unit 1, Open Storage Area, Defense Supply Center Richmond. August.

DLA, 2003. Final Consolidated Five-year Review Report, Defense Supply Center Richmond, Virginia. July.

Defense Supply Center Richmond (DSCR), 1999. Maintenance and Repair of Buildings and Grounds, Regulation 4150.1. April.

DSCR, 2006. Final Revised Human Health Baseline Risk Assessment for Operable Unit 1, Defense Supply Center Richmond. December.

DSCR, 2006. Environmental Land Use Control Implementation Plan. April.

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