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a <br /> . Because of the apparent extent of subsurface contamination, only two of the six soil samples <br /> collected from beneath the gasoline storage tanks were analyzed for TPHg and BTEX <br /> Additionally, the sample with the higher concentration TPHg was analyzed for soluble lead and <br /> ethylene dlbromlde (EDB) Laboratory analyses of the soil samples indicated that TPHg (70 <br /> ppm) was present beneath the 4,000-gal tank formerly located at the northwest corner of the site, <br /> the laboratory analyses, however, indicated that the sample collected from beneath the 8,000-gal <br /> tank, formerly located at the southeast corner of the site, contained a nondetectable (<0 5 ppm) <br /> concentration of TPHg (Table 2) Benzene was not detected in either sample analyzed by the <br /> laboratory These results however, are not likely representative of in situ contaminant <br /> concentrations because of the volatile nature of the contaminants, the sandy consistency of the <br /> soils, and the sampling and laboratory methodologies Soluble lead and EDB were not detected <br /> in soil sample S-13-3N <br /> TABLE 2 <br /> LABORATORY RESULTS OF SOIL SAMPLES <br /> TANK REMOVAL AND STOCKPILE <br /> 1766 MONTE DIABLO <br /> STOCKTON, CALIFORNIA <br /> i Sample TPHg Benzene Toluene Ethyl- Total WET <br /> Number benzene Xylenes Lead <br /> . Tank Removal <br /> S-13-3N 70 <0 125 4 17 74 <0 05 <br /> S-14-2S <0 5 <0 005 0 077 <0 005 0 054 NA <br /> Stockpile <br /> S-SP1-A,B,C 32 <0125 <0125 <0125 19 NA <br /> S-SP2-A,B,C 23 <0 005 <0 005 <0 005 3 2 NA <br /> S-SP3-A,B,C 4 5 <0 005 <0 005 <0 005 <0 015 NA <br /> S-SP4-A,B,C 37 <0 005 <0 005 099 11 NA <br /> S-SP5-A,B,C <0 5 <0 005 <0 005 <0 005 <0 015 NA <br /> Laboratory analyses performed by Matrix Environmental Laboratories <br /> Laboratory results reported In mg/kg (parts per million) <br /> TPHg = Total Petroleum Hydrocarbons as gasoline <br /> NA = Not Analyzed <br /> <0 5 = Less than the laboratory method detection limits „ <br /> LOCAL GEOLOGY <br /> The site is situated in the central part of the Great Valley Physiographic Province approximately <br /> 0 35 mi north of the Port of Stockton deep water channel turning basin (San Joaquin River) and <br /> + approximately 14 mi south of the Calaveras River The site Is flat-lying with zero relief Soil <br /> 9114193 3 1685-030 scw <br /> &Associates, Inc <br /> Mrw <br /> Environmental Scientists and Engineers <br />