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1 ' 19 December 2005 AGE-NC Project No 99-0645 ' Page 3 of 8 ' TPH-g was detected in excavation soil samples F-1, WW, EW, and NW at concentrations of 6 0 mg/kg, 23,000 mg/kg, 29 mg/kg, and 32 mg/kg,respectively BTEX compounds were detected in all excavation samples, except SW, at maximum concentrations in sample WW of 56 mg/kg ' benzene, 1,700 mg/kg toluene, 470 mg/kg ethylbenzene, and 2,900 mg/kg xylenes MTBE was detected in all excavation samples at concentrations ranging from 0 028 mg/kg (SW)to 140 mg/kg (WW) Tertiary-amyl methyl ether (TAME) was detected only in sample WW at 9 2 mg/kg, TBA ' was detected in samples F-1 and NW at 6 100 mg/kg and 0 10 mg/kg, respectively The composrted 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 at concentrations as high as 3 0 mg/kg, 0 24 mg/kg, and 3 5 mg/kg,respectively Analytical results of soil samples are summarized in Table 2 AGE calculated that approximately 126 gallons of gasoline were removed in the soil excavated ' during the interim remediation activities (Appendix A) The highest concentrations of petroleum hydrocarbon compounds left in place were detected in the sample collected from the western wall of the former excavation Lower concentrations of TPH-g 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 ' 24 PREVIOUS SITE ASSESSMENTS ' On 15 through 17 October 2001, six soil borings(B 1 through B6)were advanced at the site by AGE, three soil borings,B 1 through B3,were established as ground water monitoring wells MW-1 through MW-3, respectively Soil in the area of boring BI (MW-1) and borings B4 and B5 was found to ' contain high concentrations of petroleum hydrocarbons at depths of 15 feet bsg, with reduced concentrations encountered at depths to 70 feet bsg Ground water monitoring data from the initial ' ground water monitoring event on 02 November 2001 indicated that ground water was flowing toward the northeast, and was locally impacted by MTBE Analytical results of soil samples are summarized in Table 2, analytical results of quarterly monitoring event ground water samples ' collected between November 2001 and July 2005 are summarized in Table 3 On 27 September 2002,monitoring well MW-1 was destroyed by drilling out the entire boring length and backfilling with neat cement and bentonite in the upper 15 feet of the excavation Additionally, the domestic on-site well was destroyed by percussion explosion and backfilled with a sand and cement mix IOn 09 through 11 September 2003,a total of seven soil borings were advanced at the site boring 136' • was advanced north of the excavation area at a 20 degree angle, to an extent of 80 feet, B7 was Advanced GeoEnvironmental,Inc