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i Site Background Information Cherokee Truck Stop . AGE-NC Project No 97-0312 Page 4 of 5 13 February 1998 • June 1999- Soil through borings B 14 B 17 and monitoring well UST-6 were installed at the g site and soil and grab water samples were collected The borings were advanced to further define the hydrocarbon-impacted soil plume, UST-6 was installed to delineate the northern extent of hydrocarbon-impacted ground water Borings B 14 through B 17 were advanced to a vertical depth of approximately 100 feet below surface grade (bsg), boring UST-6 was drilled to a vertical depth of 75 feet bsg TPH-g was detected in samples B14-20 and BI 5-15 at concentrations of 570 mg/kg and 540 mg/kg, respectively TPH-d was detected in six of the 24 samples analyzed (B14-20, B14-30, B15-15, B15-20, B17-25 and B17-40) at concentrations as high as 13,000 mg/kg(B 14-20) Benzene was detected in sample B 14-20 at a concentration of 4 1 mg/kg Toluene,ethylbenzene and xylenes were detected in samples B14-20 and B15-15 at concentrations as high as 9 8 mg/kg Other petroleum hydrocarbons were not detected in the 24 soil samples analyzed MTBE was detected by EPA Method 8260 in samples B 14-20,B 17-25 and B 17-40 at concentrations of 0 41 mg/kg, 12 mg/kg and 8 1 mg/kg, respectively Tert-butanol was detected in sample B14-20 at a concentration of 0 3 mg/kg Other oxygenates were not detected in these three samples or in sample B15-15 MTBE was detected by EPA Method 8020 in samples B 14-30 and B 17-50 at concentrations ' 0 of 0 051 mg/kg and 0 54 mg/kg,respectively Additionally,grab ground water samples were collected from borings B-14, B-15 and B-17 TPH-g, TPH-d, MTBE and BTEX were detected in each sample MTBE concentrations ranged from 6 4 µg/l in the sample from B- 14 to 9,700 pg/l in the sample from B-17 September 1999-Twelve soil borings were advanced at the site to further define the lateral ' and vertical extent of hydrocarbon-impacted soil Borings B 18 through B29 were advanced to vertical depths between 30 and 70 feet bsg TPH-g was detected in only one sample (B21-10) at a concentration of 6 7 mg/kg TPH-d was detected in 11 of the 39 samples ' analyzed at concentrations as high as 660 mg/kg(B21-10) Benzene was detected in four of the 39 samples at concentrations as high as 0 057 mg/kg Toluene was detected in sample B21-10 at a concentration of 0 091 mg/kg Ethylbenzene and xylenes were not detected in ' the soil samples analyzed from the September 1999 drilling MTBE was detected in three of seven soil samples analyzed by EPA Method 8260 at concentrations as high as 2 7 mg/kg Other oxygenates were not detected ' 30 July 2002-Ground water monitoring well UST-1 was destroyed by over-drilling to total depth Following over-drilling, the boring was backfilled to surface grade with portland cement in accordance with EHD regulations,the grout mixture was prepared utilizing a ratio ' of six gallons water for every 94-pound sack of portland cement • 06 December 2002-One ground water monitoring well (UST-7)was installed to a depth of ' 90 feet bsg, the well screen of UST-7 was recorded as placed between 85 feet and 90 feet bsg Soil samples were collected at 25 feet bsg and 45 feet bsg The physical properties of • soil samples MW7A-25 and MW7A-45 were described as a brown silt and a brown clay with Advanced GeoEnvironmentai,inc 1