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The following conclusions were drawn from the results of this investigation The site stratigraphy is composed predominantly of fine-grained soil consisting of silt,clayey silt, silty clay and clay, with the exception of five significant sand lenses or laycis at depths of approximately 50 feet bsg, between 60 and 75 feet bsg, between 95 and 110 feet bsg, between 120 and 130 feet bsg and between 140 and approximately 160 feet bsg CPT pore pressure dissipation tests in the sandy silt, sand and gravelly sand indicated that hydraulic conductivities were typical for sand mixtures • TPH-g and BTEX impacted soil was detected at low concentrations at 55 feet bsg, but at significant concentrations at 78 feet bsg Based on the vertical distribution of contaminants to soil from the present and previous site investigations,AGE delineated two distinct zones of contaminated soil, in fine-grained soil (HUI) at between 30 and 40 feet bsg beneath the Chevron (northeastern-most) former dispenser island, and in fine-grained soil (HU3) at 80 feet bsg The soil contamination at 30 to 40 feet bsg, which included diesel as well as gasoline products,may have originated from the overlying former Chevron dispenser island area However,based on the available data,the source for the deeper contamination at 80 feet bsg is uncertain, the former Standard Oil USTs cannot be ruled out Petroleum hydrocarbons were detected in grab ground water samples collected from the northeastern portion of the site,in the area of CPT1, CPT2 and CPT5,to approximately 180 feet bsg Based on the vertical distribution of contaminants to ground water from the present and previous site investigations, the highest concentration of contaminants appears to be at between the upper ground water surface at boring AIMW-1 and at 40 and 60 feet bsg to the 0 area of CPT1 and CPT2 The concentrations of contaminants appear to decrease vertically, towards a minimum in clay-rich fine grained soil at a depth of between 80 and 100 feet bsg Flow-,ver,petroleum hydrocarbons increase again below 100 feet bsg,to high concentrations of between 11,000 pg/1 and 14,000 p.g/l TPH-g at depths of between 120 and 150 feet bsg The vertical dzstnbution of 7PH-g concentrations suggests that the primary source of contammation may be the Chevron(northeastern)dispenser island,but does not rule out the former Standard Oil UST s as an additional source The un-gradient and cross-gradient (south) limits of petroleum hydrocarbon-impacted soil and ground water have been determine The vertical and down-gradient lateral extent of petroleum hydrocarbon-impacted soil and ground water has not been defined, at this time Advanced GeoEnvironrnentat