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Page 2 May 9, 1994 BAE31604.AS.T8 As reported in the RI/FS, benzene was found to exceed the hazardous waste Toxicity Characteristic Leaching Procedure (TCLP) level for benzene of 500 14g/1 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 µg/1 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 April 14, 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 1 indicate that the direction of groundwater flow is westerly in the vicinity of the former gasoline tanks. The groundwater flow, north of the Disco property, is inconclusive. The small groundwater elevation differences between all the monitoring wells indicated a shallow gradient. The ground water elevations increased by nearly 2 feet in all wells since the previous quarter. Historical groundwater elevation data is 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 Quality Analytical Laboratory, Redding CA, for total petroleum hydrocarbons (TPH) as gasoline; and benzene, toluene, ethylbenzene, and xylenes (BTEX) (EPA method 8015/8020). Results of the April 14, 1994 sampling event and results from previous sampling events are summarized in 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, except for low levels (below MCLs) of toluene and xylenes in MW-DIS-7D.. SCHEDULE The current schedule of activities is presented on Table 3. The schedule for construction of the planned AS/SVE system has been delayed until July 1994 to provide adequate time for public notification and permit review by the San Joaquin Valley Unified Air Pollution