Site Name: MOTTOLO PIG FARM
EPA ID: NHD980503361 EPA Region: 01 Metro Statistical Area:
BLUEBERRY HILL RD, RAYMOND, NH 03077
Operable Unit:
ROD ID: EPA/ROD/R01-91/054 ROD Date: 03/29/91
Contaminant: VOCS; TCE; TOLUENE; XYLENES; VINYL CHLORIDE; METALS; ARSENIC
Keys: NONE
Abstract:
THE 50-ACRE MOTTOLO PIG FARM SITE IS IN RAYMOND, NEW HAMPSHIRE. SURROUNDING LAND IS PRIMARILY RURAL RESIDENTIAL AND UNDEVELOPED. THE SITE INCLUDES A WOODED AREA, AN INACTIVE PIGGERY AREA COMPRISED OF SEVERAL STRUCTURES, A BUILDING DRUM DISPOSAL AREA, AND WETLANDS. AN ONSITE BROOK (BROOK A) ORIGINATING IN THE WETLANDS DISCHARGES INTO THE EXETER RIVER. PRIOR TO 1975, A PIGGERY OPERATION WAS LOCATED ONSITE. FROM 1975 TO 1979, THE OWNER DISPOSED OF 1,600 DRUMS AND PAILS CONTAINING HAZARDOUS WASTES IN A DISPOSAL AREA NORTH OF THE PIGGERY BUILDING, AND SUBSEQUENTLY FILLED IN THE AREA. IN 1979, THE STATE IDENTIFIED ONSITE BURIED DRUMS SOME OF WHICH WERE CRUSHED AND LEAKING. CONSEQUENTLY IN 1980, EPA BEGAN EXCAVATION AND STAGING OF THESE DRUMS. FROM 1981 TO 1982, EPA REMOVED AND CHARACTERIZED DRUMMED WASTE, THEN TRANSPORTED THE WASTE OFFSITE ALONG WITH 160 CUBIC YARDS OF CONTAMINATED SOIL, DRUM PARTS, AND PLASTIC SHEETING. THE AREA WAS THEN REGRADED AND SEEDED. THIS RECORD OF DECISION (ROD) ADDRESSES CONTAMINATED ONSITE SOIL, DEBRIS, AND THE ASSOCIATED GROUND WATER PLUME. THE PRIMARY CONTAMINANTS OF CONCERN AFFECTING THE SOIL, DEBRIS, AND GROUND WATER ARE VOCS INCLUDING TCE, TOLUENE, VINYL CHLORIDE AND XYLENES; AND METALS INCLUDING ARSENIC.
THE SELECTED REMEDIAL ACTION FOR THIS SITE INCLUDES INSTALLING A GROUND WATER INTERCEPTOR TRENCH UPGRADIENT OF THE FORMER DRUM DISPOSAL AREA TO REDUCE MIGRATION OF CONTAMINANTS AND FACILITATE TREATMENT OF CONTAMINATED SOIL; CAPPING THE DRUM DISPOSAL AND SOUTHERN BOUNDARY AREAS WITH TEMPORARY WATERPROOF CAPS TO IMPROVE TREATMENT EFFICIENCY; TREATING APPROXIMATELY 3,400-4,000 CUBIC YARDS OF VOC-CONTAMINATED SOIL AT THESE AREAS USING IN-SITU VACUUM EXTRACTION AND ACTIVATED CARBON TO CONTROL OFF-GASES, FOLLOWED BY ONSITE OR OFFSITE CARBON REGENERATION AND DISPOSAL; ALLOWING THE CONTAMINATED GROUND WATER PLUME TO BE RESTORED THROUGH NATURAL ATTENUATION; MONITORING GROUND WATER AND SURFACE WATER; AND IMPLEMENTING INSTITUTIONAL CONTROLS INCLUDING DEED AND GROUND WATER USE RESTRICTIONS, AND SITE ACCESS RESTRICTIONS SUCH AS FENCING. THE PRESENT WORTH COST FOR THIS REMEDIAL ACTION IS $690,000, WHICH INCLUDES A PRESENT WORTH O&M COST OF $280,000.
PERFORMANCE STANDARDS OR GOALS; SOIL CLEANUP LEVELS WERE ESTABLISHED TO PROTECT GROUND WATER FROM SOIL LEACHATE. GROUND WATER INTERIM CLEANUP LEVELS WERE BASED ON FEDERAL SDWA MCLS AND MCLGS, OR STATE HEALTH ADVISORY LEVELS. THE ESTIMATED TIME FRAME FOR THE RESTORATION OF THE OVERBURDENED GROUND WATER AFFECTED BY THE DRUM DISPOSAL AREA SOIL AND THE BEDROCK GROUND WATER AFFECTED BY THE SOUTHERN BOUNDARY SOIL TO ACCEPTABLE LEVELS BY NATURAL ATTENUATION IS 6 YEARS AND 2 YEARS, RESPECTIVELY.
Remedy:
THE SELECTED REMEDY FOR THE MOTTOLO SUPERFUND SITE INCLUDES BOTH SOURCE CONTROL AND MANAGEMENT OF MIGRATION COMPONENTS TO OBTAIN A COMPREHENSIVE REMEDY. THE SOURCE CONTROL REMEDIAL MEASURES INCLUDE:
* INSTALLATION OF A GROUNDWATER INTERCEPTOR TRENCH UPGRADIENT OF THE FORMER DISPOSAL AREA. LOWERING OF THE UPGRADIENT OVERBURDEN WATER TABLE IN THIS AREA WILL SIGNIFICANTLY REDUCE GROUNDWATER FLOW THROUGH CONTAMINATED SOILS AND, ACCORDINGLY, MIGRATION OF CONTAMINANTS FROM THE FORMER DRUM DISPOSAL AREA. DEWATERING WILL FACILITATE VES TREATMENT OF THAT PORTION OF CONTAMINATED SOILS THAT IS CURRENTLY SATURATED BY GROUNDWATER, SIGNIFICANTLY INCREASING THE EFFECTIVENESS OF SOURCE CONTROL. NO DEWATERING WILL BE REHIRED FOR THE SOUTHERN BOUNDARY AREA SINCE THE OVERBURDEN SOILS REMAIN UNSATURATED FOR MOST OF THE YEAR.
* SEALING THE GROUND SURFACE IN BOTH THE FORMER DRUM DISPOSAL AREA AND THE SOUTHERN BOUNDARY AREA WITH TEMPORARY CAPS CONSISTING OF FOUR OR SIX-MIL THICK VISQUEEN SHEETING COVERED WITH A SIX INCH LAYER OF SEEDED LOAM. THIS WILL IMPROVE THE OPERATIONAL EFFICIENCY OF THE YES BY LIMITING SHORT-CIRCUIT AIR FLOW FROM THE GROUND SURFACE TO THE EXTRACTION WELLS AND SIGNIFICANTLY REDUCING PRECIPITATION INFILTRATION. THE CAPS WILL REMAIN IN PLACE AND BE EFFECTIVE FOR THE EXPECTED OPERATIONAL PERIOD OF THE YES, BUT THEY WILL NOT BE DESIGNED TO MAINTAIN THEIR INTEGRITY ON A PERMANENT BASIS.
* INSTALLATION AND OPERATION OF A VACUUM EXTRACTION SYSTEM (VES) TO REMOVE AIR AND VAPOR PHASE VOCS PRESENT IN THE SOIL PORE SPACE (SOIL GAS) IN THE FORMER DRUM DISPOSAL AND SOUTHERN BOUNDARY AREAS. VOCS SORBED ONTO SOILS WILL PARTITION FROM THE SOILS INTO THE REPLACEMENT AIR AND BE REMOVED BY THE VACUUM SYSTEM.
THE MANAGEMENT OF MIGRATION REMEDIAL MEASURES INCLUDE:
* NATURAL ATTENUATION OF CONTAMINATED GROUNDWATER TO LOWER CONTAMINANT CONCENTRATIONS THROUGH PHYSICAL, CHEMICAL AND BIOLOGICAL PROCESSES UNTIL GROUNDWATER CLEANUP LEVELS ARE MET. AFTER COMPLETION OF SOURCE REMEDIATION AT EACH OF THE TWO AREAS, NO FURTHER CONTAMINATION WILL BE ADDED TO THE GROUNDWATER AT LEVELS WHICH WOULD PREVENT ATTAINMENT OF THE GROUNDWATER CLEANUP LEVELS. IT HAS BEEN ESTIMATED THAT OVERBURDEN GROUNDWATER WHICH HAS BEEN AFFECTED BY THE FORMER DRUM DISPOSAL AREA SOILS WILL CLEAN ITSELF TO THE GROUNDWATER CLEANUP LEVELS WITHIN APPROXIMATELY SIX YEARS AFTER COMPLETION OF SOURCE REMEDIATION. BEDROCK GROUNDWATER SHOULD ATTAIN GROUNDWATER CLEANUP LEVELS EARLIER. FOR THE BEDROCK GROUNDWATER AFFECTED BY THE SOUTHERN BOUNDARY AREA SOIL CONTAMINATION (NO APPRECIABLE OVERBURDEN GROUNDWATER WAS FOUND IN THIS AREA), APPROXIMATELY TWO YEARS WILL BE NEEDED TO ACHIEVE GROUNDWATER CLEANUP LEVELS.
ADDITIONAL MEASURES INCLUDE:
* A SECURITY FENCE CONSISTING OF APPROXIMATELY 1,300 LINEAR FEET OF GALVANIZED CHAIN LINK FENCE, TEN FEET HIGH, TO BE INSTALLED TO CONTROL ACCESS TO THE FORMER DRUM DISPOSAL AND SOUTHERN BOUNDARY AREAS AND TO PROVIDE SECURITY FOR THE VACUUM EXTRACTION SYSTEM.
* GROUNDWATER AND SURFACE WATER MONITORING INITIATED DURING REMEDIAL DESIGN AND CONTINUING FOR THREE YEARS AFTER ATTAINING GROUNDWATER CLEANUP LEVELS TO ASSESS THE EFFECTIVENESS OF REMEDIATION AND TO CONFIRM THAT CONTAMINANT CONCENTRATIONS IN GROUNDWATER ATTAIN CLEANUP LEVELS.
* INSTITUTIONAL CONTROLS TO BE IMPLEMENTED WHICH WOULD RESTRICT THE USE OF CONTAMINATED GROUNDWATER AND PREVENT DISTURBANCE OF ON-GOING REMEDIAL ACTIONS. THE OBJECTIVES OF THE INSTITUTIONAL CONTROLS SHALL BE TO ENSURE THAT NO ACTIVITIES TAKE PLACE AT THE SITE OR IN PROXIMITY TO THE SITE WHICH WOULD EITHER AFFECT IMPLEMENTATION OF THE SELECTED REMEDY OR CAUSE EXPOSURES TO HAZARDOUS SUBSTANCES. EXAMPLES OF ACCEPTABLE INSTITUTIONAL CONTROLS INCLUDE USE RESTRICTIONS IMPOSED ON DEEDS AND ZONING ORDINANCES, AMONG OTHERS.