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§eofogicaf7ecknics 2nc. Page 4 <br /> City of Escalon <br /> Soil&Groundwater Report <br /> Project No. 750.2 <br /> f March 15, 1999 <br /> 2.2.1 Chemical Distribution in the Soil <br /> The analytical results for the soil samples collected during the February 12 & 23, 1999 <br /> drilling by GTI are summarized as follows: <br /> HP-1 <br /> • Contained high levels of BTEX, TPH-G, MTBE and TBA in the 11 and 20-foot <br /> intervals. ; <br /> • Contained moderate to low levels of these compounds from 30 feet down to the <br /> groundwater,interface at 61 feet. <br /> HP-2, HP-3, HP-4, & HP-6 <br /> • Were non-detect for BTEX, TPH-G and the fuel oxygenate compounds except for low <br /> levels of MTBE detected in HP-2 at 60 feet and HP-4 at 10 feet. <br /> 1 <br /> HP-5 <br /> • Contained low levels of BTEX in the 21, 35 and 45-foot samples. <br /> + Contained moderate to low levels of MTBE and TBA from 21 to 61 feet. <br /> • Contained a low amount of PCE (6.9 ug/Kg) in the 56 foot interval. <br /> 2.2.2 Chemical Distribution in the Ground Water <br /> The analytical results for the groundwater grab samples collected during the February 12 & <br /> 23, 1999 drilling by GTI are summarized as follows: <br /> HP-1 <br /> • Moderate levels of BTEX, TPH-G and MTBE , <br /> HP-2 <br /> • Low levels of BTEX, TPH-G and MTBE <br /> HP-3 <br /> • Non-detect for all analytes <br /> HP-4 <br /> • Low levels of BTEX, TPH-G and MTBE <br /> HP-5 <br /> „ Low levels of BTEX, TPH-G and MTBE <br /> HP-6 <br /> • Non-detect for all analytes <br /> 3.0 DISCUSSION <br /> The probable source for the majority of this contamination was either the dispenser island or <br /> piping near HP-1. <br /> It appears that the contamination primarily moved vertically in the soil with very little lateral <br /> spread. Supportive evidence is the elevated concentrations in HP-1 contracted to the non- <br /> detects in boreholes HP-2, HP-3, HP-4 and HP-6, which are only a short distance from HP-1. <br />