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INFORMATION SHEET DEFENSE LOGISTICS AGENCY DEFENSE DISTRIBUTION REGION WEST TRACY INTERIM GROUND WATER CLEANUP SYSTEM SAN JOAQUIN COUNTY The Defense Logistics Agency, Defense Distribution Region West, Tracy (DDRW Tracy) owns and operates a ground water extraction and remediation system to cleanup pollution caused by past practices. Originally installed in 1990, the Interim Remediation System incorporated six extraction wells, an air stripping tower, and disposal to reinjection wells, infiltration galleries, and evaporation/percolation ponds. DDRW Tracy has initiated procedures to increase the effectiveness and expand the treatment capacity of the initial Ground Water Cleanup System by adding wells and disposal trenches. Beginning in November 1994, the air stripper began treating at a rate of approximately 450 gpm from an original capacity of 250 gpm. The total flow for the OU 1 is approximately 1250 gpm. The monthly median effluent limits for volatile organic compounds were set at the Best Available Technology, Economically Feasible (BAT) limit which is also the method detection limit(MDL). Daily maximum limits allow for limited excursions above the MDL. These limits are consistent with similar limits at other facilities. The monthly median Dieldrin limit is set at the MDL which is the U.S. E.P.A. 10 day SNARL, and the daily maximum allows for brief excursions above the monthly limit. DDD, DDE, and DDT monthly limits are set at the one-in- a-million cancer risk levels, and the daily limits are the California Proposition 65 trigger level. Chlordane, Monuron, and Diuron have monthly median limits which represent the background concentrations found at the facility, and the daily maximums allow for brief excursions above the monthly limit. Planning and design of a second phase to complete the Full Scale Ground Water Cleanup System began in May of 1995. A second air stripper and wastewater disposal area are expected to be constructed. The focus of this final phase of cleanup is the volatile organic constituents (VOC) ground water plume extending off-site of the main facility to Annex property to the north and northeast of the main facility. The Annex property is owned by DDRW Tracy and is leased out for agricultural use. Discharge from the ground water cleanup system at DDRW Tracy is currently regulated by Order No. 90-275. Surface water drainage is to the Old River.