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GRANITE CONSTRUCTION, FRENCH CAMP WKA No. 2088.04 December 2, 1993 Page 5 CONCLUSIONS AND RECOMMENDATIONS Laboratory test results for soil samples obtained during the construction of the three new monitoring wells (MW4, MW5 and MW6) indicate that soil contamination does not extend laterally to the locations of these wells. Additionally, laboratory test results for water samples obtained from the three new wells indicate that ground water contamination does not extend in the northerly and northeasterly directions to these wells. Analysis of the samples obtained from soils beneath the former dispenser area island following the removal of approximately 700 cubic yards of diesel contaminated soil reveal only trace �. concentrations of diesel and motor in soils of the northerly and easterly sidewalls of the excavation. Based on this information, we do not believe additional excavation at the former �. dispenser location is necessary and recommended backfilling the excavation. The excavation was backfilled by Granite Construction Company using clean fill, following authorization from San Joaquin County EHD. The soil removed from the excavation has been sampled and is being �� evaluated for disposal or on-site treatment. The former diesel and gasoline UST excavations were lined with plastic and also backfilled following authorization from San Joaquin County EHD. The stockpiles of soil removed from the +� excavation were moved to another on-site location. Based on the large volume of soil estimated in our April 29, 1993 Report of Findings to require remediation in the vicinity of the former diesel and gasoline USTs (6,000 to 6,500 cubic yards), LW we recommend that three vapor extraction wells be constructed in this area. Subsequent to the installation of these wells, we recommend that a five day pilot study be completed to evaluate the effectiveness of a soil and ground water vapor extraction remediation system. WAUACE•KUHL av 6A590C1ATEIA INC.