NORTH BELMONT PCE SITE - United States Environmental ...

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NORTH BELMONT PCE SITE

NORTH BELMONT, GASTON COUNTY NORTH CAROLINA

RECORD OF DECISION

REGION IV ATLANTA, GEORGIA SEPTEMBER, 1997

DECLARATION FOR THE RECORD OF DECISION

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SITE NAME AND LOCATION

North Belmont PCE Site North Belmont, Gaston County, North Carolina

STATEMENT OF BASIS AND PURPOSE

This decision document presents the selected remedial action for the North Belmont PCE Site in North Belmont, Gaston County, North Carolina, chosen in accordance with the Comprehensive Environmental Response, Compensation and Liability Act of 1980 (CERCLA), as amended by the Superfund Amendments and ReauthorizationAct of 1986 (SARA) and, to the extent practicable, the National Contingency Plan (NCP). This decision is based on the administrative record file for this Site.

The State of North Carolina concurs with the selected remedy.

ASSESSMENT OF THE SITE

Actual or threatened releases of hazardous substances from this Site, if not addressed by implementing the response action selected in this Record of Decision, may present an imminent and substantial endangerment to public health, welfare, or the environment.

DESCRIPTION OF THE SELECTED REMEDY

This remedy addressees the principle threat posed by the Site. The major threat is the contaminated groundwater emanating from beneath the Site.

The major components of the selected groundwater remedy include:

4 Installation of an in-well vapor stripping system to treat contaminated groundwater that is above Maximum Contaminant Levels or the North Carolina Groundwater Standards, whichever are more protective for each particular contaminant;

4 In-situ bioremediation;

North Belmont PCE Site Record of Decision North Belmont, Gaston County, NC September, 1997

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Connection of affected residences, businesses, churches, etc currently not on city water to the City of Belmont or Gaston County public water supply;

Optional wellhead treatment for affected private wells; and Continued analytical monitoring for contaminants in groundwater.

STATUTORY DETERMINATIONS

The selected remedy is protecl^ rif ^firian health and the environment, complies

with Federal and State requiremeillljfii^

or relevant and appropriate

to the remedial action, and is cQ|t||||6t!^. This rerti^iy utilizes permanent solutions and

alternative treatment technoloo^|||i|)ipmaximum exteirtt practicable, and satisfies the

statutory preference for remed|||||||i^rriploy treatrfieiit that reduces toxicity, mobility, or

volume as a principal element. Since this remedy may result in hazardous substances

remaining on-site above health:base||ley^

conducted within five years

after commencemer^of remedi||^^

continues to provide

adequate protection ijf Human

Richard D. Green, Act|rjgQire^Q|or

Date

Waste

North Belmont PCE Site Record of Decision North Belmont, Gaston County, NC September, 1997

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TABLE OF CONTENTS______________________________________

SECTION

PAGE NO.

1.0 SITE NAME, LOCATION AND DESCRIPTION

1-1

A. Introduction

1-1

B. Site Description

1-1

C. Demography

1 -4

D. Surrounding Land/Water Use

1-4

E. Topography

1-4

F. Climate

1-4

G. Geology

1-5

H. Hydrogeology

1-6

I. Hydrology

1-7

2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES

2-1

A. Site History

2-1

B. Previous Investigations

2-1

C. Site Regulatory Actions

2-3

3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION

3-1

4.0 SCOPE AND ROLE OR RESPONSE ACTION

WITHIN SITE STRATEGY

4-1

5.0 SUMMARY OF SITE CHARACTERISTICS

5-1

A. Source Area/Soil Investigation

5-1

B. Surface Water and Sediment Investigation

5-3

C. Residential Well Survey

5-3

D. Private Well Sampling

5-3

E. Shallow Groundwater Investigation

5-7

F. Top-of-Bedrock Groundwater Investigation

5-7

G. Bedrock Groundwater Investigation

5-12

H. Other Constituents in Groundwater

5-12

I. Ecological Survey

5-16

6.0 SUMMARY OF SITE RISKS

6-1

A. Chemicals of Concern

6-1

B. Exposure Assessment

6-4

C. Toxicity Assessment

6-4

D. Risk Characterization

6-7

F. Conclusions

6-9

North Belmont PCE Site Record of Decision North Belmont, Gaston County, NC September, 1997

TABLE OF CONTENTS CONT'D

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SECTION

PAGE NO.

7.0 APPLICABLE OR RELEVANT AND

APPROPRIATE REQUIREMENTS (ARARS)

7-1

8.0 REMEDIAL ACTION OBJECTIVES

8-1

9.0 DESCRIPTION OF ALTERNATIVES

9-1

A. Alternative 1 - No Action

9-1

B. Alternative 2 - Limited Action

9-2

C. Alternative 3 - Groundwater Exposure Abatement

9-2

D. Alternative 4 - Groundwater Exposure Abatement

and Groundwater Treatment

9-2

10.0 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES A. Alternative 1 - No Action B. Alternative 2 - Limited Action C. Alternative 3 - Groundwater Exposure Abatement D. Alternative 4 - Groundwater Exposure Abatement and Groundwater Treatment E. Comparative Analysis of Alternatives

10-1 10-2 10-4 10-6

10-8 10-10

11.0 THE SELECTED REMEDY

11-1

A. Groundwater Remediation

11-1

B. Additional Sampling Requirements

11-5

12.0 DOCUMENTATION OF SIGNFICANT CHANGE

12-1

APPENDIX A- RESPONSIVENESS SUMMARY APPENDIX B - AUGUST 7, 1997 PUBLIC MEETING TRANSCRIPT APPENDIX C - STATE CONCURRENCE

North Belmont PCE Site Record of Decision North Belmont, Gaston County, NC September, 1997

TABLE OF CONTENTS CONT'D

FIGURES 1-1 Site Location Map 1-2 RI/FS Study Area

2-1 1991 Investigation 2-2 1996 Residential Well Sampling 5-1 Soil Sampling Locations

5-2 SW/Sed Sampling Locations 5-3 Residential Well Survey 5-4 Shallow Temporary Well Locations 5-5 Shallow PCE Isopleth 5-6 Monitoring Well Locations

5-7 Top of Bedrock PCE Isopleth 5-8 Bedrock PCE Isopleth 5-9 1 ,1 -DCE Concentrations in Top of Bedrock 5-10 1,1 -DCE Concentrations in Bedrock 5-1 1 Trichlorofluoromethane Concentrations in Bedrock

5-12 Ecological Survey Locations ? \ .. ? .

TABLES

5-1 1996 Residential Well Sampling Results 5-2 Main Contaminants in the Shallow GW Plume 5-3 Main Contaminants in the Temp Top of Bedrock Plume 5-4A Main Inorganic Contaminants in Perm TOB Plume 5-4B Main Organic Contaminants in Perm TOB Plume 5-5A Main Organic Contaminants in Bedrock Plume 5-5B Main Inorganic Contaminants in Bedrock Plume 6-1 Exposure Point Concentrations in GW 6-2 Exposure Point Concentrations in Soil 6-3 Carcinogenic Toxicity Assessment 6-4 Noncarcinogenic Toxicity Assessment 6-5 Cancer and Noncancer Risks 6-6 Quantified Risk for Each Chemical of Concern 7-1 Chemical-specific ARARs 7-2 Location-specific ARARs 7-3 Action-specific ARARs 8-1 Remediation Goals for Groundwater 9-1 Remedial Action Alternatives for Groundwater 10-1 Comparative Analysis for Groundwater 11-1 Capital Costs for Selected Remedy 11-2 Remedial Action Operation Costs

North Belmont PCE Site Record of Decision North Belmont, Gaston County, NC September, 1997

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PAGE NO. 1-2 1-3 2-2 2-4 5-2 5-4 5-5 5-8 5-9 5-11 5-13 5-15 5-17 5-18 5-19 5-20

PAGE NO.

5-6 5-7 5-11 5-11 5-12 5-14 5-14 6-2 6-3 6-5 6-6 6-8 6-10 7-2 7-4 7-5 8-1 9-1 10-11 11-2 11-3

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1.0 SITE NAME, LOCATION, AND DESCRIPTION__________________

A. Introduction

The North Belmont PCE Site (hereinafter referred to as the "Site" or the "North Belmont Site") consists of two closed dry cleaning operations located in North Belmont, Gaston County, North Carolina (latitude 35?16'24.5" and longitude 81?03'04.5"). These two areas are referred to as "Source Area A" and "Source Area B" (Figure 1-1).

B. Site Description

Source Area A is located at Roper's Shopping Center in Land Lot 5, Parcel 15-18A

on Woodlawn Avenue. The shopping center includes Roper's Furniture Store, a Baptist

church, and a cabinet manufacturing shop. The former dry cleaner facility is approximately

0.75 acres in size and is bounded to the east and west by residential neighborhoods; to the

north by a cemetery and an undeveloped wooded tract; and to the south by North Belmont

Elementary School.

,

Two mobile homes are located on the property in the back of the shopping center, each occupied by one tenant. There was believed to be a buried septic tank behind the

shopping center building near the mobile homes. A flea market is held on the lawn between the shopping center and the elementary school five days per week. The shopping center is fenced along the southern and eastern boundary. The western portion of the shopping center is covered with an asphalt parking lot, and the eastern portion is covered with soil and grass. The terrain is relatively flat with a gentle slope toward the northeast to

an unnamed tributary of Fites Creek,

Source Area B is located at the northeastern corner of Acme Road and Suggs Road in Land Lot 11, Parcel 15-18. This parcel has been converted to residential property. The majority of the area surrounding Source Area B is residential with a few small businesses. A cabinet shop is located to the north.

In addition, a previous refrigerator repair shop and a machine shop were also suspected to be potential sources of contamination. The refrigerator repair shop, now closed, is located at the intersection of Julia Street and Acme Road in land lot 15-18A parcel #32. This is a small commercial strip area with residential property surrounding the

Site, except for a cabinet shop and a well drilling company located to the east. The machine shop is located at the corner of Acme and Centerview Roads and is encompassed by residential neighborhoods. Figure 1-2 shows the approximate RI/FS study area.

North Belmont PCE Site

Record of Decision

North Belmont, Gaston County, NC

September, 1997

1-1

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SOURCE AREA

CoxEten. Grore

' NORTH BELMONT PCE

SOURCE: DeLORME MAP EXPERT

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FIGURE 1-1. SITE LOCATION MAP

NOTE: NOT TO SCALE

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