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. 11 February 2003 AGE-NC Project No. 98-0520 Page 3 of 7 2.4. ASSESSMENT OF HYDROCARBON-IMPACTED SOIL AND GROUND WATER On 05 February 1999,AGE advanced four soil probe borings at the site. Probe borings B-1 and B-2 were advanced within the former UST No.2 and No. 1 excavations to depths of 40.25 and 25.25 feet bsg,respectively.Probe boring B-3 was advanced within the former waste oil UST No.3 excavation -to 20.25 feet bgs. The fourth boring, B-4 was-advanced northwest of the former dispenser islands ' to 20.25 feet bgs. • TPH-g and various BTEX compounds except benzene were detected in the soil samples ' collected from,between 20 and 25 feet bsg from all of the borings, at concentrations as high as 670 mg/kg and 13 mg/kg(xylenes),respectively,in soil saniple 13-2-20.25%TPH-mo was detected in soil samples collected between 20 and 25 feet bsg in borings B-2 through B-4 at ' a maximum concentration of 120.' mg/kg (B-2-20.25'). Fuel oxygenating compounds, including MTBE, were not detected above the elevated reporting limit. • TPH-g and TPH-mo were detected in ground water samples collected from borings B-1 ' through B-4 at concentrations as high as 16,000 micrograms per liter (4g/f) in sample B-1, and 110,000 ug/l in sample B-2, respectively. Various BTEX compounds except benzene were detected in all ground water samples 'at a maximum concentration of 1,400 µg/l zylenes, in sample B-1. The fuel oxygenating compounds MTBE and tert-Butanol were detected in sample B-4 at concentrations of 19 µg11 and 80 µg/l, respectively. The lead scavenger 1, 2-dichloroethane(1,2-DCA)was detected in sample B-4 at 0.59 ug/l. On 09 and 10 December 1999,five soil borings were advanced at-the site to a depth of.35 feet below surface grade (bsg) for installation of monitoring wells MW-1 through MW-5. • TPH-g and TPH-mo were detected in the soil sample collected at 20 feet bsg in pilot boring MW-4 at concentrations of 160 mg/kg and 4.7 mg/kg, respectively; TPH-mo was detected ' in borings MW-1 at 25-feet bsg and MW-5 at 20 feet bsg at concentrations of 5.7 mg/kg,and 7.5 mg/kg, respectively. MTBE and BTEX compounds were not detected above laboratory reporting limits in any of the soil samples collected and analyzed. ' On 30 and 31 October 2001,four soil borings were advanced at the site for installation of monitoring wells MW-6 and MW-8 through MW-10. MW-8 through MW-10 were advanced to a depth of 35 ' feet below surface grade (bsg); MW 5 was advanced to 50 feet bsg. • TPH-g was detected in soil sample MW-8-30'and MW-9-20 at concentrations of 15 and.130 milligrams per kilograms(mg/kg),respectively,TPH-d was detected in soil sample MW-6- ' 35 and MW-9-20 at concentrations of 1.2 and 150 mg/kg, respectively, and TPH-mo was detected in sample MW-9-20 at 10 mg/kg; no. petroleum hydrocarbon compounds were detected in any of the soil samples analyzed from boring MW-10. The BTEX compounds ' toluene, ethylbenzene and xylenes were detected in soil samples MW-6-35, MW-8-30 and • MW-9-20 at maximum concentrations of 0.093 mg/kg, 0.83 mg/kg and 0.7 mg/kg, . Advancer!GeoEnvironmental,Inc. 1 ,