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Environmental Technology Inc .,_. Their report states that the soil sample "appears to contain a mineral spirit, Stoddard solvent, paint thinner, or an er li t dr based solvent. Me- -QW further states that the release occurred between four and twe ve years ' ago (i e.. 1984 to 1992) (Friedman & Bruya, 1995) Friedman & Bruya utilized capillary gas chromatography using a flame ionization detector (FID) to analyze the sample Using the FID, to analyze the soil sample, 10 ppm of TPH-d (EPA ' 8015M) was found in the sample. Their report notes that the material present is lighter than diesel #2 TPH-g and BTEX are also present in the soil sample (Table 2). A copy of the laboratory report is presented in Appendix C. 5.0 QUARTERLY M0MTORING ' As a part of on-going quarterly monitoring plan. SOTA s engineer measured the depth to groundwater at all eight monitoring wells (MW-1 through MW-8) on February 8, 1996 The depth to the water level and the corresponding surface elevations, with respect to mean sea level, are presented in Table 3 SOTA's engineer informed San Joaquin County Environmental Health Division of the proposed sampling event, in advance, on January 31, 1996 The sampling program was conducted as described below A minimum of 4 well casing volumes, which was calculated to be approximately 16 gallons, was purged from each of the eight wells During purging operations the temperature, pH, and conductivity were measured with the water flowing through a continuous flow chamber. The pumping was carried on until the temperature, pH, and conductivity values stabilized within at least 5% of previous readings Monitoring wells MW-1 through MW-8 were purged of ' approximately 25-gallons of water per well using a 2-inch submersible pump Copies of the field observation which includes temperature, pH, and conductivity values are enclosed in Appendix F Proper decontamination procedures which included flushing the pump and hose with a solution of detergent and water, followed by clean tap water, with a final rinse using deionized water were employed. The purged water is stored in 55-gallon DOT approved drums which have been labeled and stored on-site for subsequent treatment/disposal. Adequate time was allowed for recovery after purging All monitoring wells were allowed to recover to 95 percent or more of their static water level condition. At the time of groundwater sampling, neither free ' product nor sheen was noticed in any of the monitoring wells Dedicated bailers were used for sampling activities at each of the wells, in order to prevent possible cross contamination. The eight water samples were collected and stored in an ice chest maintained at 4° C. Appropriate chain of custody was prepared prior to transporting to a State certified laboratory. Del Mar Analytical, Irvine, CA performed the 1 laboratory analyses All the water samples were analyzed for Total Petroleum Hydrocarbons (TPH) as gasoline (Volatile Fuel Hydrocarbons) and Benzene, Toluene, Ethylbenzene, and Total Xylenes (BTEX) following EPA Methods 8015M/8020. The analytical results are presented in Table 4 7