Site Name: SAVAGE MUNICIPAL WATER SUPPLY
EPA ID: NHD980671002 EPA Region: 01 Metro Statistical Area: 5350
NEAR RT 101, MILFORD, NH 03055
Operable Unit:
ROD ID: EPA/ROD/R01-91/059 ROD Date: 09/27/91
Contaminant: VOCS; BENZENE; PCE; TCA; TCE; METALS; ARSENIC; CHROMIUM; LEAD
Keys: NONE
Abstract:
THE SAVAGE MUNICIPAL WATER SUPPLY SITE IS LOCATED IN MILFORD, NEW HAMPSHIRE. THE SITE AND SURROUNDING PROPERTIES ENCOMPASS THE SAVAGE MUNICIPAL WELL, FOUR MAJOR INDUSTRIAL FACILITIES, AND TWO FISH HATCHERIES. LAND USE INCLUDES RESIDENTIAL, AGRICULTURAL, HEAVY AND LIGHT INDUSTRIAL, AND COMMERCIAL AREAS. THE SITE IS LOCATED WITHIN THE 100 YEAR FLOODPLAIN OF THE SOUHEGAN RIVER, WHICH IS THE PRINCIPAL STREAM FLOWING THROUGH THE SITE. FROM THE 1940'S TO THE 1980'S, PROCESS AND WASTE WATERS FROM THE INDUSTRIAL FACILITIES WERE RELEASED UNTREATED TO THE GROUND WATER OR TO THE SURFACE WATERS FLOWING THROUGH THE SITE. IN 1983, THE STATE IDENTIFIED CONCENTRATIONS OF SEVERAL VOCS THAT WERE ABOVE DRINKING WATER STANDARDS IN WATER FROM THE SAVAGE MUNICIPAL WELL AND WATER DRAWN FROM THE WELL SUPPLYING A NEARBY TRAILER PARK. AT THE STATE'S REQUEST, EPA CONDUCTED A REMOVAL ACTION IN 1983. THIS INCLUDED TEMPORARILY SUPPLYING BOTTLED WATER TO AFFECTED RESIDENCES IN THE TRAILER PARK, AND CONNECTING THE RESIDENCES TO THE EXISTING MUNICIPAL WATER SUPPLY SYSTEM. THIS REMEDIAL ACTION ADDRESSES POTENTIAL RISKS TO FUTURE USE OF THE AQUIFER CAUSED BY GROUND WATER CONTAMINATION AT THE SITE, WITHIN A 6,000 BY 2,500-FOOT CONTAMINATED GROUND WATER PLUME. THIS GROUND WATER PLUME WAS DIVIDED INTO TWO ZONES; THE CONCENTRATED PLUME, WHICH CONTAINS THE HIGHEST CONCENTRATIONS OF CONTAMINANTS; AND THE EXTENDED PLUME, WHICH HAS THE REMAINDER OF THE CONTAMINATED GROUND WATER. THE PRIMARY CONTAMINANTS OF CONCERN AFFECTING THE GROUND WATER ARE VOCS INCLUDING BENZENE, PCE, TCA, AND TCE; AND METALS INCLUDING ARSENIC, CHROMIUM, AND LEAD. THE SELECTED REMEDIAL ACTION FOR THIS SITE INCLUDES ONSITE PUMPING AND TREATMENT OF THE CONCENTRATED AND EXTENDED PLUME AREAS USING AIR STRIPPING AND ULTRAVIOLET OXIDATION; DISCHARGING THE TREATED GROUND WATER ONSITE; USE OF NATURAL ATTENUATION TO AID IN CONTAMINATED GROUND WATER REMEDIATION UNTIL CLEAN-UP LEVELS ARE MET; IMPLEMENTING GROUND WATER, SURFACE WATER, AND SEDIMENT MONITORING PROGRAMS DURING REMEDIATION; AND IMPLEMENTING INSTITUTIONAL CONTROLS INCLUDING DEED AND GROUND WATER USE RESTRICTIONS. THE ESTIMATED PRESENT WORTH COST FOR THIS REMEDIAL ACTION IS $15,500,000, WHICH INCLUDES AN ANNUAL O&M COST OF $1,400,000 FOR 30 YEARS. PERFORMANCE STANDARDS OR GOALS; INTERIM GROUND WATER CLEAN-UP LEVELS FOR CARCINOGENIC COMPOUNDS HAVE BEEN SET AT THE MORE STRINGENT OF MCLS, NON-ZERO MCLGS, OR AN EXCESS CANCER RISK OF (10-6). CLEAN-UP LEVELS FOR NON-CARCINOGENIC COMPOUNDS HAVE BEEN SET AT THE NON-ZERO MCLG OR AN HI=1. GROUND WATER CLEAN-UP LEVELS INCLUDE BENZENE 5 UG/L (MCL), PCE 5 UG/L (MCL), TCE 5 UG/L (MCL), ARSENIC 50 UG/L (MCL), CHROMIUM 100 UG/L (MCL), AND LEAD 15 UG/L (ACTION). FINAL PROTECTIVE CLEAN-UP LEVELS WILL BE DEVELOPED AFTER INTERIM LEVELS HAVE BEEN ATTAINED OR THE REMEDY IS OTHERWISE DEEMED PROTECTIVE.
Remedy:
THIS ROD SETS FORTH THE SELECTED REMEDY FOR SAVAGE MUNICIPAL WATER SUPPLY SITE, WHICH ADDRESSES MANAGEMENT OF MIGRATION TO MEET CLEANUP GOALS. THE SELECTED REMEDY IS A COMPREHENSIVE REMEDY SINCE NO SOURCE CONTROL COMPONENT IS NECESSARY. THIS REMEDY ADDRESSES THE POTENTIAL RISKS TO THE FUTURE USES OF THE AQUIFER CAUSED BY THE GROUNDWATER CONTAMINATION AT THE SITE. THE REMEDIAL MEASURES TO ADDRESS THE GROUNDWATER CONTAMINATION INCLUDE:
* INSTALLATION OF A GROUNDWATER EXTRACTION AND TREATMENT SYSTEM AT THE CONCENTRATED PLUME AREA. THE SYSTEM WILL CONTAIN AND REMOVE HIGHLY CONTAMINATED GROUNDWATER FOR TREATMENT USING AIR STRIPPING AND ULTRAVIOLET OXIDATION.
* INSTALLATION OF A GROUNDWATER AND TREATMENT SYSTEM WITHIN THE EXTENDED PLUME AREA. THE SYSTEM WILL REMOVE CONTAMINATED GROUNDWATER FROM TWO LOCATIONS NEAR THE MIDDLE OF THE PLUME AND TWO LOCATIONS NEAR THE END OF THE PLUME FOR TREATMENT USING ULTRAVIOLET OXIDATION.
* RELIANCE ON NATURAL ATTENUATION OF CONTAMINATED GROUNDWATER TO LOWER CONTAMINANT CONCENTRATIONS THROUGH PHYSICAL, CHEMICAL AND BIOLOGICAL PROCESSES UNTIL GROUNDWATER CLEANUP LEVELS ARE MET.
* UTILIZATION OF INSTITUTIONAL CONTROLS TO REDUCE THE RISK TO PUBLIC HEALTH FROM CONSUMPTION OF THE GROUNDWATER. INSTITUTIONAL CONTROLS MAY INCLUDE DEED RESTRICTIONS AND ZONING ORDINANCES TO RESTRICT THE USE OF CONTAMINATED GROUNDWATER. INSTITUTIONAL CONTROLS SHALL BE IMPOSED IN THE AREA WHERE THE RISK TO PUBLIC HEALTH IS OUTSIDE EPA'S ACCEPTABLE RISK RANGE.