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k'" KLEINFELDER i r . I EXECUTIVE SUMMARY This is a report of Kleinfelder's groundwater monitoring for the former Disco Facility located at 110 Filbert Street in Stockton, California. Mr. Steve Erickson of Del Monte Foods., retained Kleinfelder to conduct this groundwater sampling and analysis. On February 21, 2002, seventeen monitoring wells were sampled by Del-Tech Geotechnical Support Services. The monitoring wells (MW-DIS-1, MW-DIS-2, MW-DIS-4, MW-DIS-7s, MW-DIS-7d, MW-DIS-9, MW-DIS-11s, MW-DIS-lld, MW-DIS-12, MW-DIS-13, MW-DIS- 14s, MW-DIS-14d, SVE-North, SVE-South, and NP-1-70', NP-1-80'and NP-1-90') were sounded for depth to groundwater and sampled. The monitoring wells were sampled generally in accordance with the "Groundwater Monitoring Frequency Decision Tree" established for Del Monte by CH2M Hill (previous consultant). Additional monitoring wells were included at Del Monte Foods' request. The depth to groundwater ranged from 41.14 feet below the top of the well casing (MW-DIS- I ls) to 50.24 feet below the top of the well casing (MW-DIS-12). Groundwater elevations for the monitoring wells ranged from --30.11 feet (MW-DIS-7s/d) to —30.82 feet (MW-DIS-13). Groundwater flow direction at the site is estimated to be towards the southeast at approximately 0.0005 ft./ft. The seventeen groundwater samples were analyzed for the following analysis: benzene, toluene, ethylbenzene, xylene, Total Petroleum Hydrocarbon as gasoline (TPH-g), 1,2-Dichloroethane (1,2-DCA), 1,2-Qibromoethane (EDB), and tert-Butyl Alcohol (TBA). Additionally, MW-DIS- 1, MW-DIS-2, MW-DIS-4, MW-DIS-7s, MW-DIS-7d, SVE-North, SVE-South, and NP-1-70', NP-1-80'and NP-1-90' were analyzed for the oxygenates Di-isopropyl Ether (DIPS); Ethyl t- Butyl Ether(ETRE), Methyl t-Butyl Ether (MTBE), and t-Amyl Methyl Ether(TAME). The detected concentrations of TPH-g found in the groundwater samples collected ranged from } 64 ug/l (MW-DIS-lls) to 180,000 ug/l (NP-1-80'). TPH-g was not detected in nine of the seventeen groundwater samples analyzed above the laboratory detection limit (< 50 ug/1). The concentrations of TPH-g appear to attenuate with distance downgradient of the source area. Benzene was detected in eight of the seventeen groundwater samples analyzed ranging from 0.81 ug/l (MW-DIS-2) to 26,000 ug/l (NP-1-80'). The remaining nine groundwater samples showed non-detect concentrations of benzene above the laboratory reporting limit (ND < 0.3 ug/1). The Primary Maximum Contaminant Level (PMOL) for benzene is 1 ug/l. The detected concentration of benzene is below the PMCL for benzene in water in monitoring well MW-DIS- 2 only. The remaining seven detected concentrations of benzene exceed the MCL for benzene in groundwater. 12280_MON12002R 4 �9 Page 1 of 15 ®2002,Kleinfelder,Inc May 10,2002 }