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Site Background Information - Guardino and Crawford Page 4 of 6 • TPH-g and BTEX compounds were detected in soil samples collected from probe boring P9. TPH-g was detected in samples from 15 and 20 feet bsg at 11 mg/kg and 76 mg/kg, respectively. TPH-g and BTEX compounds were not detected in soil samples collected from probe boring P9. BTEX compounds were detected in soil samples collected from probe boring P10 at 30 feet bsg at concentrations as high as 0. 12 mg/kg (xylenes). Benzene was detected in two soil samples, 1`9-20 and P10-30, at concentrations of 0. 14 mg/kg and 0.021 mg/kg, respectively. MTBE was not detected in the soil samples analyzed by EPA Method 8020. • TPH-g and BTEX compounds were detected in each of the grab ground water samples collected and analyzed. TPH-g was detected in the ground water samples collected from probe boring P9 at a concentration of 35,000µg/1, at a concentration of 760 µg/1 from the grab groundwater sample collected from boring P10, and at a concentration of 660 µg/1 from the grab ground water sample collected from boring P11 . BTEX compounds were detected at concentrations as high as 3 ,400 gg/l (xylene) in the grab ground water sample collected from P9. Benzene was detected at concentrations as high as 380 µg/l in the grab ground water sample collected from P9. MTBE was detected in one ground water sample analyzed by EPA Method 8020 at a concentration of 7. 7 µg/1. MTBE was detected by EPA Method 8260 in grab water samples P9, P10, and P11 at concentrations of 21 µg/1, 1 . 6 µg/1, and 5 .3 µg/1, respectively. TBA was also detected EPA Method 8260 in the grab ground water sample collected from boring Pl l at a concentration of 22 µg/l. On 20 September 2004, two additional ground water monitoring wells (MW-7 and MW-8) were installed at the site. Pilot borings MW4 and MW- 8 were completed as ground water monitoring wells ofthe same designations using 2-inch diameter, Schedule 40 polyvinylchloride (PVC) casing; 0.020-inch slotted screen was installed from approximately 10 feet to 25 feet bsg in both borings with blank casing extending to the surface. A total of seven soil samples were collected from the borings and analyzed for the petroleum hydrocarbon constituents; no petroleum hydrocarbon constituents were detected at or above laboratory reporting limits. On 12 October 2004, one soil boring (CPT- 1 ) was advanced on-site utilizing cone penetrometer testing (CPT) technology. A total of three grab ground water samples were collected (one sample each from HU1 , HU2, and HU3) and submitted for laboratory analysis for petroleum hydrocarbon constituents; no petroleum hydrocarbons were detected at or above laboratory reporting limits. STRATIGRAPHY In general, brown, dry to damp silty clay, clayey silt, and clay was encountered from surface grade to approximately 15 feet bsg. From 15 feet to approximately 33 feet bsg, sandy material was encountered; grain size increased with depth, and sub-rounded pebbles were present with diameters as large as %Z inch. From 33 feet to 41 feet bsg, clay, silty clay, and clayey silt were primarily Advanced GeoEnviron ental, Inc.