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Former Discovery Chevrolet June 6, 1997 Tracy,California_ Report of Additional Subsurface Investigation The soil underlying the site was found to be predominantly clay and silt to the groundwater interface at about 10 to 11 feet bsg. Below this depth, sandy silt to silty sand was encountered. Gravel was encountered in the first 8 feet of the boring for MW-1, indicating that this well was located at least partially in UST cavity backfill. FIELD WORK Prior to performing the field work, Underground Service Alert was notified and well permits were obtained from the San Joaquin County Public Health Services/Environmental Health Division (SJC PHS/EHD) for all of the soil borings and groundwater monitoring wells (copies are included as Appendix B). The Horizon Field Methods and Procedures are included as Appendix C. On April 3 and 4, 1997, field work was conducted in accordance I f i with the Horizon Site Safety Plan dated April 3, 1997. Drilling, Soil Sampling, and Groundwater Sampling On April 3, 1997, a Horizon geologist observed the drilling of soil borings MW-4 and MW- 5, and hand borings SA through SK. Mr. Steve Sasson of SJC PHSIEHD was also present to witness this portion of the field work. The location of the soil borings and monitoring wells were selected to attempt to delineate gasoline hydrocarbons in the soil and groundwater beneath the site as proposed in the work plan. The soil borings to be completed as monitoring wells were drilled and sampled using a truck-mounted CME-75 drill rig equipped with 8-inch diameter hollow-stem augers. Drilling was performed by Mitchell Drilling Environmental Corporation, a C-57 licensed contractor in Rancho Cordova, California. Groundwater was encountered in the borings at a depth of approximately 8% to 9 feet bsg. During drilling, soil samples were collected from the borings at 5-foot intervals from the ground surface to the total depth of the borings. Soil samples and cuttings were evaluated for the presence of petroleum hydrocarbon vapors with an organic vapor meter 3001-11.rpt 3 HORIZON ENVIRONMENTAL INC.