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SITE CLOSURE EVALUATION REPORT <br /> Beacon Station No. 502 <br /> r 35 North Cherokee Lane <br /> Lodi, California <br /> Delta Project Pio. D093-907 <br /> approximate vertical extent of soil containing petroleum hydrocarbons in concentrations greater than <br /> 100 mg/kg prior to site remediation is shown on cross-section A-A' presented in Figure 4. <br />' Based on the analytical results for soil samples collected from soil borings SB-1, SB-2, and SB-3, sampled <br />' by Delta in April 1993, and on the analytical results for soil samples collected in February 1995 from <br /> the maximum depths of the tank and pump island excavations, it would appear that virtually all soil <br /> containing detectable concentrations of total petroleum hydrocarbons (TPH) as gasoline, TPH as diesel, <br /> and benzene have been remediated or removed. Some relatively low concentrations of toluene {0.0071 <br /> mg/kg), ethylbenzene (0.016 mg/kg), and total xylenes (0-2 mg/kg) may remain beneath the north end <br /> of the tank pit at a depth of approximately 26 feet bsg. <br />' 3.4 Distribution of Petroleum Hydrocarbons in Ground Water <br /> A summary of available analytical results for ground water samples is presented in Table 3. The highest <br /> concentrations of petroleum hydrocarbons were detected in a ground water sample collected from <br /> monitoring well MW-1 on October 14, 1986. This sample reportedly contained benzene at a <br />' concentration of 331 micrograms per liter (µg/L) and TPH as gasoline at a concentration of 3,750 µg/L. <br /> Liquid-phase petroleum hydrocarbons have never been detected in the site monitoring wells. A map <br /> showing the approximate extent of TPH as gasoline in ground water prior to site remediation (based on <br /> analytical results for samples collected March 3, 1989) is presented in Figure 7. <br /> Detectable concentrations of petroleum hydrocarbons have not been present in any ground water samples <br />' collected from wells at the site since December 1989, with the exception of a sample collected from j <br /> monitoring well MW-1 on June 29, 1990 which contained benzene at a concentration of 0.6 ,ug/L, and <br /> a sample collected from monitoring well MW-4 on May 20, 1992 which contained TPH as gasoline at j <br />' a concentration of 68Itg/L. <br /> 1 RPT 139.5Js <br />