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4 h r 07 July 2000 AGE-NC Project No 98-0448 I ' Page 3 of 12 ' evaluate aquifer characteristics such as hydraulic conductivity,transmissivity and draw-down at various pumping rates • In August 1999, a 48-hour In-Situ Air Sparge (IAS) pilot test was performed at the site to ' assess feasibility of IAS as a remediation technique • In November 1999,two soil vapor extraction(SVE)wells (VW- 1 and VW-2)were installed at the site to accommodate an SVE pilot test Soil samples collected from VW-1 at a depth ' of 30 feet bsg contained TPH-g and BTEX compounds at concentrations as high as 590 mg/kg Analytical results of soil samples are summarized in Table 1 ' In December 1999, an 8-hour SVE pilot test was performed at the site to provide data to assess SVE as a potential component for the final remediation system Analytical results of ' vapor samples collected during the pilot test are shown in Table 3 • Between October 1994 and September 1999, thirteen ground water monitoring and sampling events were performed at the site TPH-g was detected in samples collected from wells MW-1,MW-2, MW-3, MW-4A, MW-4B and MW-6 at concentrations as high as 170,000 µg/l, BTEX compounds were detected from all wells at the site at concentrations as high as 40,000 kcg/l Fuel oxygenating compounds(methyl tertiary butyl ether,di-isopropyl ether and tert butanol) were detected from wells MW-1, MW-2, MW-4B, MW-6 and MW-8 at concentrations as high as 91 µg11 ' Additional background information, prepared by John P Cummings & Associates, is summarized 3 in the Report 4`h Quarterly Monitoring, dated 21 November 1997 and submitted to the PHS-EHD ' Additional background information for the site was prepared by AGE and submitted to the PHS-EHD in the following reports Quarterly Report, June 1998 (dated 20 July 1998), Quarterly ' Report, September 1998 (dated 29 October 1998), Quarterly Report, December 1998 (dated 29 January 1999), Quarterly Report, March 1999 (dated 04 June 1999), Quarterly Report, June 1999 1 (dated 25,August 1999) and Quarterly Report, September 1999 (dated 08.November 1999) , 2 3 REGIONAL GEOLOGIC SETTING The property is situated within the Great Valley Geomorphic Province of California, a large, 1 elongate, northwest trending,,asymametric structural trough The Great Valley Province has been filled with thick sequences of sediment ranging in age from Jurassic to Recent, creating a nearly flat- lying alluvial plain,extending from the Tehachapi Mountains in the south to the Klamath Mountains in the north The western and eastern boundaries of this province are comprised of the California Coast Range and the Sierra Nevada, respectively Rocks composing the basement complex of the province have not been completely defined but are believed to be metamorphic and igneous in origin Advanced GeoEnvironmental,Inc