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1 <br /> ' 23 November 1998 <br /> AGE-NC Project No 95-0103 <br /> Page 3 of 7 <br /> ' • Total petroleum hydrocarbons quantified as gasoline (TPH-g) in accordance with EPA <br /> method 8015m, <br /> ' • Volatile aromatic compounds(benzene,toluene, ethyl-benzene and total xylenes BTEX) in <br /> accordance with EPA method 8020 j <br /> i <br /> ' Based on the low concentrations VOC and BTEX extracted over the previous quarter, the Catalytic <br /> Oxidizer was removed from the soil-vapor extraction system The change in the design was agreed <br /> upon with Mr Chapin and Mr Harlin Knoll of the San Joaquin County Health Department to reduce <br /> ' the overall cost of the extraction operation and maintain an extraction potential on the site The soil- <br /> vapor concentrations have been measured with an OVM and analyzed to confirm the reduced <br /> concentrations of vapor emissions <br /> ' 3.0. FINDINGS <br /> 3 1 RELATIVE GROUND WATER ELEVATION <br /> Ground water elevation decreased approximately 1 5 feet between June and September 1998 The <br /> relative ground water elevation at the site appears to be depressed on the northern portion of the <br /> ' property (Figure 3) The ground water on the site is inferred to be moving toward the ground water <br /> depression <br /> 1 <br /> 3 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES <br /> ' TPH-g was detected in samples from wells MW-1, MW-3, MW4 and MW-5 at concentrations of <br /> 1,200 micrograms per literµg11, 7,000 µg/l, 21,000 µg/1 and 910µg11,respectively <br /> ' Benzene was detected in wells MW-1, MW-3 and MW4 at concentrations of 67µg/l, 150µg/l and <br /> 3,300µg11,respectively Benzene was not detected in wells MW-2,MW-5,MW-6 and MW-7 Other <br /> ' BTE&X compounds were detected in wells MW-1, MW-3, MW-4 and MW-5 at concentrations as <br /> high as 3,800µg11 <br /> ' Petroleum hydrocarbons were not detected In the samples collected from wells MW-2, MW-6, and <br /> the eastern most well MW-7 <br /> ' MTBE was detected in the samples collected from wells MW-1 and MW-3 at concentrations of 13 <br /> µg/1 and 1 5µg/l,respectively,DIPE was detected in samples collected from wells MW-3 and MW- <br /> 5 at concentrations of 40µg/1 and 32µg/l, respectively; TBA was detected in the samples collected <br /> Advanced GeoEnvironmentol,Inc <br />