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I07 March 2002 AGE-NC Project No 99-0645 Page 2 of 9 I2 2 INTERIM SOIL REMEDIATION On 21 March 2000, 195 metric tons of impacted soil were excavated from the former tank pit by AGE, utilizing an excavator outfitted with a 2 45 cubic-yard bucket Following the removal of the roriginal spoil backfill material,the excavation was enlarged and deepened to an approximate depth of 22 feet bsg On 22 March 2000, the impacted soil was transported from the site and disposed at ' Forward Landfill TPH-g was detected in soil samples collected from the excavation floor(F-1), and walls(WW,EW ' and NW)at 6 0 mg/kg,23,000 mg/kg,29 mg/kg and 32 mg/kg,respectively TPH-g was not detected in sample SW ' Elevated concentrations of BTEX compounds were detected in sample WW at concentrations ranging from 56 mg/kg of benzene to 2,900 mg/kg of xylenes Samples F-1, EW and NW also contained BTEX at concentrations ranging from below detection limits(benzene in sample NW)to ' 4 1 mg/kg of xylenes in sample EW BTEX compounds were not detected in sample SW Elevated concentrations of MTBE were detected in samples F-1, WW and EW at concentrations of 10 19,000 gg/kg, 140,000 µg/kg and 15,000 gg/kg,respectively MTBE was also detected in samples SW and NW at 28 µg/kg and 91 µg/kg, respectively TAME was detected only in sample WW at 9,200 pg/kg and TBA was detected only in samples F-1 and NW at 6,100 gg/kg and 100 gg/kg, respectively The composited stockpile soil samples contained TPH-g at concentrations ranging from 1,900 mg/kg to 2,100 mg/kg BTEX compounds ranged from below laboratory detection limits (benzene in sample SPA-D) to 280 mg/kg(xylenes in sample SPH-L) MTBE, TAME and TBA were detected as high as 3,000 pg/kg, 240 gg/kg and 3,500 gg/kg, respectively, in the stockpile soil samples Analytical results of soil samples are summarized on Table 1 AGE calculated that approximately 126 gallons of gasoline were removed in the soil excavated during the interim remediation on the site The highest concentrations of petroleum hydrocarbons compounds left in place were detected in I samples collected from the western wall of the former excavation Lower concentrations of petroleum hydrocarbons as gasoline were also detected in the floor sample and samples collected from the north and west sidewalls Fuel oxygenates, including MTBE, TAME and TBA were detected in all samples ' 23 SITE HYDROGEOLOGIC CONDITIONS • The closest surface water feature to the site is the Calaveras River (Diverting Canal), located ' advanced CeoEnvironmental,Inc