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Mr. Michael Collins Page 2 �. February 21, 1994 BAE31604.AS shallow groundwater. The shallow groundwater surface was found to exist at approximately 75 feet below ground surface within fine sandy silts, clayey silts and sand. Groundwater was observed to flow northwesterly at a gradient between 0.0005 and 0.0013. As reported in the RI/FS, benzene was found to exceed the hazardous waste Toxicity Characteristic Leaching Procedure (TCLP) level for benzene of 500 µgll in Monitoring Wells MW-DIS-1 and -2. Benzene concentrations in Monitoring Wells MW-DIS-1, -2, -3, and -7D have exceeded the California Maximum Contaminant Level (MCL) for benzene of 1 µg11 Del Monte submitted a conceptual remediation plan to Michael Collins of San Joaquin County Public Health Services (PHS) on August 19, 1993. The remediation plan specifies air sparging combined with soil vapor extraction (AS/SVE) to remediate the source of gasoline constituents in the subsurface beneath the Disco Property. GROUNDWATER MONITORING/QUALITY The quarterly monitoring event conducted on January 11 and 12, 1994 consisted of water level measurements and groundwater sampling. Water level depths were measured in monitoring wells MW-DIS-1 through MW-DIS-7S and MW-DIS-7D. Monitoring well locations and groundwater elevation contours are shown on Figure 1. The groundwater elevation contour lines shown on Figure I indicate that groundwater is flowing in a westerly direction with a shallow gradient. Water level elevations from this quarter and previous monitoring events are summarized on Table 1. Monitoring wells MW-DIS-3, -4, -6, -7S, and -7D were sampled as part of the quarterly groundwater quality monitoring program. Monitoring well purge and sampling data are attached. The groundwater samples were analyzed by the CH2M HILL Analytical Laboratory for total petroleum hydrocarbons (TPH) as gasoline; and benzene, toluene, ethylbenzene, and xylenes (BTEX) (EPA method 801518020). Results of the January 1994 sampling event and results from previous sampling events are summarized on Table 2. The laboratory report is also attached. The analytical results indicate that petroleum hydrocarbons were not present in any of the monitoring well samples. SCHEDULE The current schedule of activities is presented on Table 3. As discussed with Michael Collins/PHS on February 16, 1994, the schedule for construction of the planned ASISVE system has been delayed until May or June 1994 to provide adequate review time of the air permit by the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD). quarterly.rep