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26 July 2002 AGE-NC Project No. 97-0326 Page 3 of 10 • TPH-g was detected in initial ground water samples collected from MW-1 through MW-3 at a maximum concentration of 330,000 micrograms/liter(µg/1) in the sample from MW-3. BTEX compounds were detected at concentrations as high as 29,000µg/1, 54,000 gg/l,6,500 µg/1 and 36,000 µg/l,respectively(MW-3).MTBE was detected in all three well samples at a maximum concentration of 510µg/l(MW-1).In addition,TBA was detected in MW-1 and MW-2 at a maximum concentration of 830 µg/1 (MW-1). • Monitoring well installation and initial monitoring activities were described in the AGE- prepared Monitoring Well Installation Report, dated 02 June 1999. • Between February and November 2001,AGE advanced five paired cone penetrometer testing (CPT) soil borings (CPT-1 through CPT-5) at the site to depths between 100 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 14,000 gg/l(CPT-4); BTEX compounds at concentrations as high as 4,000 µg/1 benzene (CPT-4); MTBE concentrations as high as 1.3 gg/l (CPT-4); and TBA at concentrations as high as 5.0 µg/l (CPT-2). Analytical results of grab ground water samples are summarized in Table 1. • Based on CPT data, AGE identified a vadose zone and six potential hydrologic units informally identified as: Hydrologic Unit 1 (HUI), located between 30 and 70 feet bsg; Hydrologic Unit 2 (HU2), located between 70 and 85 feet bsg; Hydrologic Unit 3 (HU3), located between 85 and 95 or 100 feet bsg;Hydrologic Unit 4(HU4), located between 95 or 100 feet and 120 feet bsg; Hydrologic Unit S (HUS), located between 120 feet and approximately 135 feet bsg; and Hydrologic Unit 6 (HU6), located between 135 feet and at least 150 feet bsg. Geologic cross sections A-A'and B-B'were generated from the CPT data (Figures 3 and 4), depicting the informal hydrologic units and petroleum hydrocarbon concentrations beneath the site. • Results of the February 2001 investigation were reported in Cone Penetrometer Testing (CPT) Report - February 2001, dated 19 June 2001; results of the November 2001 investigation were reported in Cone Penetrometer Testing(CPT) Report-November 2001, dated 25 March 2002. Between December 1998 and May 2002,ten 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 2). Elevated TPH-g, BTEX and MTBE concentrations have been detected in water samples collected from all the wells. Analytical results of ground water sampling events performed at the site are summarized in Table 2. Advanced GcoEnvironmcntal.Inc.