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• 23 July 2002 AGE-NC Project No 97-0249 Page 3 of 8 as 3,400 gg/l(benzene in MW-3),and MTBE at concentrations as high as 38 gg/l Analytical results of soil and ground water samples are summarized in Tables 2 and 4, respectively, results of the March 1999 investigation were reported in Quarterly Report - April 1999, dated 17 May 1999 • January and November 2001 - AGE advanced nine cone penetrometer testing (CPT) soil borings(P-10 through P-18) at the site to depths between 120 and 150 feet bsg to assess the extent of petroleum-impact and to identify potential hydrologic units TPH-g was detected in grab water samples at concentrations as high as 7,500 pg/1 (P-12), TPH-d at concentrations as high as 2,300 µg/l (P-12), BTEX compounds at concentrations as high as 2,100 µg/1 (P-12), MTBE concentrations as high as 32 gg/l, and 1,2-dichloro ethane (1,2-DCA) at concentrations as high as 6 8 µg/1 Analytical results of grab ground water samples are summarized in Table 3 Based on CPT data, AGE interpreted the CPT data to identify a vadose zone and five potential hydrologic units informally identified as Hydrologic Unit I (HUI), located between 10 and 35 feet bsg,Hydrologic Unit 2 (HU2), located between 35 and 60 feet bsg, Hydrologic Unit 3 (HU3), located between 60 and 90 feet bsg, Hydrologic Unit 4 (HU4), located between 90 and 110 feetbsg,and Hydrologic Unit S(HUS), located between 110 feet and at least 135 feet bsg Geologic cross sections D-D', E-E'and F-F'were generated from the CPT data (Figures 3 ,4 and 5), depicting the informal hydrologic units and petroleum hydrocarbon concentrations beneath the site Results of the January 2001 investigation were reported in Cone Penetrometer Testing Site Investigation - First Quarter 2001, dated 23 March 2001, results of the November 2001 investigation were reported in Cone Penetrometer Testing Site Investigation - Fourth Quarter 2001, dated 15 March 2002 Between April 1999 and March 2002,eleven ground water monitoring events were performed at the site to monitor dissolved petroleum hydrocarbon concentrations in ground water and to characterize ground water flow direction and gradient on the site (Table 4) Generally, elevated TPH-g, TPH-d, and BTEX concentrations were detected in water samples collected from wells MW-1, MW-2, MW-3 and MW-6, lesser concentrations were detected at wells MW-4 and MW-5 at isolated occurrences Generally, low concentrations of MTBE were detected from wells MW-1, MW-2, MW-4 and MW-6 Analytical results of ground water sampling events performed at the site are summarized in Table 4 Advanced GeoEnvironmental,Inc