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• 11 February 2003 AGE-NC Project No. 98-0520 ' Page 3-of 21 ' Additional information regarding history of the UST use, tank tests,product inventory and repairs are not known to AGE. { 3.0. 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. I 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 tto 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 sample B-220.25';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(µg11) in sample B-1, ' and 110,000 p.g/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 gg/l zylenes, in sample B-1. The fuel oxygenating compounds MTBE and tert-Butanol were ' detected in sample B-4 at concentrations of 19 gg/l and 80 gg/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 T5 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 Advanced Geo Environmental,Inc.