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(VYATC former wastewater treatment system. No other constituents tested were detected above their respective MCLS including 1,1,1 trichloroethane (90 ppb) detected in MW-3. The MCL for 1,1,1 trichloroethane is 200 ppb. • July 1992 - Groundwater Monitoring and Sampling - In July 1992, groundwater samples and water level measurements were collected from the six on-site monitoring wells. The groundwater gradient was determined to be northwest. Groundwater analytical results indicated the presence of nitrate (45-64.6 ppm) and sulfate (390 ppm) above MCLS of 45 ppm and 250 ppm, respectively. Additionally, VOCs including bromodichloromethane (0.8-1.1 ppb), chloroform (2.2-3.9 ppb) and 1,1,1 trichloroethane (24 ppb) were detected but were below their MCLS of 100 ppb, 100 ppb, and 200 ppb, respectively. No other constituents tested were detected. • December 1995 - Wastewater Treatment System Closure - The final volume of wastewater was treated on September 18, 1995 by the former MQUAD anodization and wastewater treatment system. Treatment equipment was subsequently dismantled and water washed by Olin Interconnect Technology (OIT) personnel to remove residues. Tanks and associated equipment were then moved to 555 Carnegie Street in Manteca, California and reassembled. Advanced Environmental Technical Services (AETS) of Hayward, California performed initial decontamination of the former wastewater treatment compound (WWTC) on November 8, 1995. On December 4, 1995, scrubbing and rinsing of the compound walls was repeated by AETS to remove cleaning residues that remained on the walls. Water generated by the decontamination procedure was subsequently transferred to the nearby on-site wastewater treatment system for treatment and disposal. On November 9, 1995, Smith Technology personnel, under contract with OIT, collected 4 soil samples from test pits located around the perimeter and inside the WWTC. Three soil samples were collected around the asphalt perimeter of the WWTC at depths from 2.5 to 3.0 feet below ground surface (bgs). One soil sample (TP-4) was collected inside the WWTC at the bottom of the deepest sump. The depth of the sump was 7.5 feet below the top of the retaining wall (4.5 feet bgs) and the sample was collected an additional 1.9 feet below this depth. The soil did not exhibit any evidence of contamination and no staining or odor was observed in the field. Samples were collected in clean brass tubes, immediately capped on both ends with Teflon tape and plastic caps, and put on ice in a cooler. The samples were analyzed for pH, aluminum, lead, sulfate, calcium, and sodium. A review of the analytical data indicates metals were not detected above typical of San Francisco Bay area concentrations (USGS Professional Paper 1270, April 1992). WA16962\REP0RT8\W0RK_PLN.D0C 3