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SM CLOSURE EVALUATION REPORT Ultramar Station No. 696 2448 West Kettleman Lane Lodi, California Delta Project No. D093-916 Page 3 1 elevation data is presented in Table 1. Ground water has typically flowed toward the southeast across the site. 3.3 Distribution of Petroleum H drocarbons in Soil iA summary of available analytical results for soil samples collected from soil borings is presented in Table 2, and a summary of analytical results for soil samples collected during tank and product line ' replacements is presented in Table 3. Locations of the soil borings are shown in Figure 3, and tank pit and product line sampling locations are shown In Figure 7. Analytical results indicate that the highest concentrations of petroleum hydrocarbons in soil were detected ' in a sample collected from the northeast corner of the former tank pit location (Sample SS-1) in March 1989. The initial analysis of this sample indicated that benzene was present at a concentration of 150 milligrams per kilogram (mg/kg) and total petroleum hydrocarbons (TPH) as gasoline was present at a concentration of 23,000 mg/kg. The approximate lateral and vertical extent of petroleum hydrocarbons in soil as of May 1987 is illustrated in diagrams prepared by J.H. Kleinfelder and Associates (Kleinfelder) which are presented in Appendix B. The approximate lateral and vertical extent of petroleum hydrocarbons currently remaining in soil as assessed by soil borings drilled by Delta in August and September 1994 is shown in Figures 8 and 9, respectively. 3.4 Distribution of Petroleum Hydrocarbons in Ground Water A summary of available analytical results for ground water samples is presented in Table 4. The highest ' concentrations of petroleum hydrocarbons were detected in a ground water sample collected from monitoring well MW-19 on November 23, 1987. This sample reportedly contained benzene at a concentration of 7,900,000 micrograms per liter (µg/1..) and TPH as gasoline at a. concentration of 30,000,000 ug/L. Liquid-phase petroleum hydrocarbons were reportedly present in some monitoring wells from 1987 to 1989 but records of product thicknesses are not available. RPT134.SJS