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Rf[MlCIl-f-tfR1YfR <br /> Mr. Charles Leubner <br /> 23 September 1997 <br /> IPage 4 <br /> Gasoline Tank <br /> Gasoline hydrocarbons were detected in only one soil sample collected from the soil boring located <br /> directly over the tank excavation (SB-1). The sample collected at a depth of 10 feet below the <br /> ground surface (sample 061) was found to contain toluene at 0.005 mg/Kg, ethylbenzene at 0.008 <br /> mg/Kg, and total xylenes at 0.059 mg/Kg. Total petroleum hydrocarbons as gasoline, ethylene <br /> dibromide, and MTBE were not detected above the reporting limits in this sample. The next <br /> deepest sample from SB-1 was collected from a depth of 15 feet below the ground surface, which <br /> was approximately 2 feet below the groundwater surface encountered in the soil boring. <br /> Hydrocarbon analyses on this sample did not detect hydrocarbons at concentrations above <br /> reporting limits; however, the following constituents were detected in the groundwater sample <br /> collected at this depth: total petroleum hydrocarbons as gasoline at 30,600 ug/L, benzene at 20 <br /> ug/L, toluene at 1,400 ug/L, ethylbenzene at 484 ug/L, and xylenes at 6,060 ug/L. These <br /> concentrations exceed the recommended Regional Water Quality Control Board (RWQCB) Water <br /> I Quality Goals for Components of Petroleum-Based Fuels (RWQCB Memorandum dated 13 May <br /> 1993, Water Quality Goals for Components of Petroleum-Based Fuels an "Mun" Designated <br /> Waters) for total petroleum hydrocarbons as gasoline (5 ug/L), benzene (1.0 ug/L), toluene (42 <br /> ug/L), ethylbenzene (29 ug/L)and xylenes(17 ug/L). <br /> Based on these results, the lateral extent of hydrocarbons in soil appears to be defined by the soil <br /> borings located around the tank excavation. The vertical extent of hydrocarbons in soil appears to <br /> be between 10 and 15 feet below the ground surface. <br /> l <br /> Diesel Tank <br /> IDiesel hydrocarbons were not detected above reporting limits in samples from either of the two soil <br /> borings drilled at the site (SB-5 and SB-6). Soil boring SB-5 was located near the southeast comer <br /> of the excavation where diesel product was detected during the sampling conducted as part of the <br /> removal of the tank. This sample from the tank excavation was collected from a depth of 13 feet <br /> below the ground surface and contained diesel at a concentration of 1,200 mg/Kg. This sample can <br /> be compared to the sample collected from a depth of 15 feet in SB-5 which contained no detectable <br /> concentrations of diesel hydrocarbons, benzene, toluene, ethylbenzene, or xylenes. <br /> CThe groundwater sample collected at a depth of 15 feet below the ground surface (just below the <br /> groundwater surface) contained toluene at 1.2 ug/L, ethylbenzene at 1.2 ug/L, and xylenes at 8.3 <br /> ug/L. Total petroleum hydrocarbons as diesel and benzene were not detected above reporting <br /> Climits. The concentrations of hydrocarbons detected in the groundwater sample are below their <br /> respective RWQCB Water Quality Goals. <br />