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Record of Decision System (RODS)

NCR CORP. (MILLSBORO PLANT)

Abstract

Site Name:  NCR CORP. (MILLSBORO PLANT)
Address:  MITCHELL RD POB 607 
City & State:  MILLSBORO  DE  19966
County:  SUSSEX
 
EPA ID:  DED043958388
EPA Region:  03
 
NPL Status:  Currently on the Final NPL
 
ROD Type:  Record of Decision
ROD ID:  EPA/ROD/R03-91/122
ROD Date:  08/12/1991
Operable Unit(s):  01
 
Media:  GROUNDWATER
 
Contaminant:  VOCS, PCE, TCE, OTHER ORGANICS, METALS, CHROMIUM, LEAD, SOIL
 
Abstract:  THE 58-ACRE NCR, MILLSBORO SITE IS A FORMER MANUFACTURING FACILITY IN MILLSBORO, SUSSEX COUNTY, DELAWARE. LAND USE IN THE AREA IS MIXED RESIDENTIAL, AGRICULTURAL, AND INDUSTRIAL WITH A SMALL STREAM, IRON BRANCH, BORDERING THE SITE TO THE NORTH AND NORTHEAST. FROM 1965 TO 1967, DENNIS MITCHELL INDUSTRIES (DMI) CONDUCTED MANUFACTURING OPERATIONS ON-SITE. REPORTEDLY, PLATING ACTIVITIES AND OTHER PROCESSES GENERATED WASTEWATER AND SLUDGE THAT WERE STORED IN AN ON-SITE LAGOON. NCR CORPORATION PURCHASED THE PLANT IN 1967 AND MANUFACTURED MECHANICAL CASH REGISTERS FROM 1967 TO 1975, AND ELECTRONIC TERMINAL EQUIPMENT FROM 1975 TO 1980. NCR'S ACTIVITIES INCLUDED CHROMIUM PLATING, ENAMELING, HEAT TREATING, AND DEGREASING OPERATIONS USING TCE. TCE AND OIL WASTES WERE DISPOSED OF OFF-SITE; AND OIL, GREASE, AND PAINT WASTES WERE DRUMMED AND STORED ON-SITE PRIOR TO OFF-SITE DISPOSAL. WASTE SLUDGE ASSOCIATED WITH THE CHROMIUM PLATING PROCESSES WAS TREATED ON-SITE AND DIRECTED TO ON-SITE LAGOONS FOR SEDIMENTATION AND CLARIFICATION PRIOR TO DISCHARGE TO IRON BRANCH. NCR ALSO DISPOSED OF THE WASTE SLUDGE IN A PIT ALONG THE EASTERN BOUNDARY. FROM 1981 TO 1983 UNDER STATE DIRECTION, NCR CONDUCTED ON-SITE INVESTIGATIONS, WHICH REVEALED GROUND WATER CONTAMINATION BY VOCS AND CHROMIUM ABOVE LEVELS OF CONCERN. IN 1981, NCR EXCAVATED AND DISPOSED OF OFF-SITE APPROXIMATELY 315 CUBIC YARDS OF LAGOON SLUDGE AND OTHER WASTES DURING RCRA CLOSURE OF THE FACILITY. IN 1988, NCR INSTALLED A GROUND WATER RECOVERY WELL AND AIR STRIPPER TO PREVENT CONTINUING MIGRATION OF A TCE GROUND WATER PLUME. THIS RECORD OF DECISION (ROD) ADDRESSES A FINAL REMEDY FOR GROUND WATER CONTAMINATION. THE PRIMARY CONTAMINANTS OF CONCERN AFFECTING THE GROUND WATER ARE VOCS, MAINLY TCE; AND CHROMIUM.

THE SELECTED REMEDIAL ACTION FOR THIS SITE INCLUDES PUMPING AND TREATMENT OF CONTAMINATED GROUND WATER USING AIR STRIPPING, FOLLOWED BY CARBON ADSORPTION, AND COAGULATION AND FILTRATION, IF NECESSARY, TO REMOVE CHROMIUM; CONTROLLING AIR EMISSIONS FROM THE GROUND WATER TREATMENT SYSTEM, IF NECESSARY; DISCHARGING THE TREATED WATER ON-SITE TO SURFACE WATER AND/OR THROUGH GROUND WATER INFILTRATION GALLERIES; CONDUCTING A WELL SURVEY TO IDENTIFY ALL WELLS LOCATED WITHIN A ONE-MILE RADIUS OF THE SITE; CONDUCTING SEDIMENT, GROUND WATER, AND SURFACE WATER MONITORING; AND IMPLEMENTING INSTITUTIONAL CONTROLS INCLUDING GROUND WATER USE AND DEED RESTRICTIONS. THE ESTIMATED PRESENT WORTH COST FOR THIS REMEDIAL ACTION IS $4,749,000, WHICH INCLUDES AN ANNUAL O&M COST OF $859,000.

PERFORMANCE STANDARDS OR GOALS; CHEMICAL-SPECIFIC GROUND WATER CLEAN-UP GOALS ARE BASED ON SDWA MCLS AND NON-ZERO MCLGS, AND INCLUDE TCE 5 UG/L (MCL) AND CHROMIUM 100 UG/L (MCL). DISCHARGE LIMITATIONS ARE SDWA MCLS AND NON-ZERO MCLGS, SDWA UNDERGROUND INJECTION CONTROL LIMITS; CWA-NPDES; CWA-AWQC AND STATE REQUIREMENTS.
 
Remedy:  THIS RECORD OF DECISION ADDRESSES THE GROUND WATER CONTAMINATION IN THE AQUIFERS UNDERLYING THE SITE. THE REMEDY FOR THIS SITE WAS SELECTED AFTER CAREFUL EVALUATION OF THE OVERALL CONDITIONS AT THE SITE. THE GROUND WATER AT THE SITE IS HIGHLY CONTAMINATED WITH VOLATILE ORGANIC COMPOUNDS (VOCS), PRIMARILY TRICHLOROETHYLENE, AND TO A LESSER EXTENT CHROMIUM. THE CONTAMINATED GROUND WATER CONTINUES TO MIGRATE AND POSES A POTENTIAL THREAT TO HUMAN HEALTH AND POTENTIAL DRINKING WATER SOURCES IF NOT ADDRESSED BY THIS REMEDIAL ACTION. THE SELECTED REMEDY CALLS FOR TREATMENT OF VOCS AND ALSO INCLUDES A CONTINGENCY FOR PROVIDING TREATMENT FOR CHROMIUM IN GROUND WATER. INCLUDING CHROMIUM TREATMENT AS A CONTINGENCY IS BASED ON THE LIMITED NUMBER OF WELLS (2) ON-SITE WHICH HAVE CHROMIUM CONCENTRATIONS ABOVE THE MAXIMUM CONTAMINANT LEVEL (MCL). THESE WELLS ARE BELIEVED TO BE WITHIN THE CONE OF INFLUENCE OF THE PRESENT GROUND WATER RECOVERY WELL WHICH PUMPS GROUND WATER TO AN AIR STRIPPER WHICH HAS BEEN IN OPERATION SINCE JULY 1988. ANALYSIS OF THE AIR STRIPPER EFFLUENT HAS CONSISTENTLY SHOWN CHROMIUM CONCENTRATIONS BELOW MCLS. FURTHER STUDIES WILL BE PERFORMED DURING THE PREDESIGN PHASE TO DETERMINE IF THE CHROMIUM TREATMENT WILL BE NECESSARY.

THE MAJOR COMPONENTS OF THE SELECTED REMEDY ARE;
* EXTRACTION OF CONTAMINATED GROUND WATER USING ADDITIONAL RECOVERY WELLS UNTIL CLEAN UP LEVELS ARE ACHIEVED
* TREATMENT OF VOC CONTAMINATION IN GROUND WATER USING AN AIR STRIPPER FOLLOWED BY CARBON ADSORPTION OF THE AIR STRIPPER EFFLUENT UNTIL THE CLEANUP LEVELS (MCLS AND NON-ZERO MCLGS) ARE ACHIEVED
* A PROVISION FOR CHROMIUM TREATMENT USING COAGULATION AND FILTRATION, IF DETERMINED NECESSARY BY EPA TO ACHIEVE EFFLUENT LIMITATIONS
* A PROVISION FOR AIR EMISSIONS CONTROLS, IF DETERMINED NECESSARY BY EPA, DURING PREDESIGN STUDIES
* A COMBINED DISCHARGE TO SURFACE WATER AND/OR ON-SITE GROUND WATER INFILTRATION GALLERIES
* CONDUCTING A WELL SURVEY TO DETERMINE THE LOCATION OF ALL WELLS WITHIN A ONE MILE RADIUS OF THE SITE, IN ORDER TO UPDATE THE PREVIOUS WELL SURVEY
* CONTINUED QUARTERLY MONITORING OF GROUND WATER UNTIL THE CLEAN UP LEVELS (MCLS AND NON-ZERO MCLGS) ARE ACHIEVED
* INSTITUTING AN ANNUAL MONITORING PROGRAM FOR SURFACE WATER AND SEDIMENTS OF IRON BRANCH UNTIL THE CLEAN UP LEVELS (MCLS AND NON-ZERO MCLGS) ARE ACHIEVED
* INSTITUTIONAL CONTROLS RESTRICTING GROUND WATER USE UNTIL CLEAN UP LEVELS (MCLS AND NON-ZERO MCLGS) ARE ACHIEVED THROUGHOUT THE ENTIRE GROUND WATER PLUME BY ESTABLISHING AND ENFORCING A STATE GROUND WATER MANAGEMENT ZONE AND PROPERTY DEED RESTRICTIONS REGARDING THE INSTALLATION OF WELLS IN THE GROUND WATER MANAGEMENT ZONE.
 
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