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4 Site Background Information: Stallworth Auto Sales Page 6 of 9 On 31 January 2006, soil probe borings P-521 - 1 , P-521 -2 and P-521 -3 were advanced off-site at 521 East Oak Street, the dirtparking areato 537 East Oak Street, utilizing avan-mounted Geoprobe 5400 direct-push probing unit. All borings were advanced to 44 feet bsg, and a grab groundwater sample was collected at total depth of each boring. Ground water was encountered at approximately 42 feet bsg and stabilized at approximately 37 feet bsg in each soil boring. No analytes of concern were detected in the grab ground water samples collected from CPT-5 and probe borings P-521 - 1 , P-521 -2 and P-521 -3 . On 18, 19 and 20 Apri12007, two additional groundwater monitoring wells (MW-7 andMW-8) and four vapor extraction wells (V W- 1 through V W-4) were installed at the site. Pilot borings V W 1 and VW3 were completed as vapor extraction wells with slotted screen installed from approximately 20 to 30 feet bsg; pilot borings VW2 and VW4 were completed as vapor extraction wells with slotted screen installed from approximately 10 to 20 feet bsg; pilot boring MW7 was completed as a ground water monitoring well with slotted screen installed from approximately 60 to 70 feet bsg; and pilot boringMW8 was completed as a ground water monitoring well with slotted screen installed from approximately 59 to 69 feet bsg. • A total of fifteen soil samples collected frompilot soilborings VWl through VW4 and MW7 were analyzed; constituents of concern were detected in eight of the soil samples analyzed. • TPH-g was detected in three soil samples collected from V W l ( 20 feet, 25 feet and 30 feet), three soil samples collected from VW3 ( 20 feet, 25 feet and 30 feet), and two soil samples from MW7 (60 feet and 70 feet); concentrations ranged from 1 . 1 mg/kg (MW7-70) to 6,800 mg/kg (VW3-20). • BTEX constituents were detected in three soil samples collected from V W 1 ( 20 feet, 25 feet and 30 feet), three soil samples collected from VW3 ( 20 feet, 25 feet and 30 feet), and one soil sample from MW7 (70 feet); maximum concentrations were 0. 024 mg/kg benzene (MW7-70), 270 mg/kg toluene (VW1 -30), 220 mg/kg ethylbenzene (VW1 -20), and 950 mg/kg xylenes (VW3 -20). On 17 July2007, an 8-hour pilot test was conducted using lower vadose-screened vaporwell V W- 1 , screened from 20 feet to 30 feet bsg, as the extraction well. On 18 July 2007, an 8-hour pilot test was conducted using upper vadose-screened vapor well VW-2, screened from 10 feet to 20 feet bsg, as the extraction well. Based upon a vacuum of 0. 1 inches ofwater, the projected radius of influence (ROI) of lower and upper vadose SVE at the site will be approximately 24 feet. TPH-g was detected at a maximum concentration of 90,000 gg/l in vapor during the lower vadose SVE pilot test. Advanced GeoEnvironnnental, Inc.