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J �pu ves . x a � a m N 7821; extend to groundwater, with the highest TPH concentration noted occurring at a depth of approximately 19 feet, in boring BB-20. No TPH was detected in groundwater from 1313-20, or the up and down-gradient borings, and a maximum of 0.92 µg/L toluene was present. 6.2.5 Area B5 Area B5 (Figure 4b) is centered on boring BB-32,where TPH-cr was 900 mg/kg and TPH-d was I 170 mg/kg. Neither hydrocarbon odor nor hydrocarbon staining were observed in the soil cores. Area B5 is delineated laterally to 7.1 mg/kg TPH-d by BB-31, BB-33, BB-152, and BB-167. The vertical extent of the impacted soil is less than 9 feet bgs. No hydrocarbon impact was Idetected in groundwater. 6.2.6 Area B6 Area B6 (Figure 4b)is centered on BB-40, where up to 80,000 mg/kg TPH-cr and 36,000 mg/kg TPH-d were detected in the soil. Hydrocarbon staining,hydrocarbon odor, and separate phase hydrocarbons were observed between 4.5 feet and 14 feet bgs. No benzene was detected in this area. The TPH concentrations attenuate sharply between 9.5 and 16.5 feet, from 80,000 mg/kg TPH-cr at 9.5 feet to 52 mg/kg TPH-cr at a depth of 15.5 feet. Impacted soil in Area 6 is defined laterally to a TPH of 44 mg/kg or less by BB-39 and BB-41 through BB-43. Groundwater samples were collected from borings BB-40, BB-41, and BB-42. Groundwater at BB-40 contained 5,200 µg/L TPH-cr, 3,000 µg/L TPH-d, and 0.42 µg/L benzene. However, TPH and benzene were not detected in groundwater from BB-41 and BB-42; low concentrations of other BTEX compounds were noted. The lateral extent of groundwater impact is therefore . Idefined. r 6.2.7 Area B7 Area B7 (Figure 4b) is centered on BB-46, BB-50, and BB-51. In BB-46, hydrocarbon staining was present in the soil cores between 4.5 feet and 7 feet; hydrocarbon odor was present between 4.5 feet and 10 feet bgs. Neither hydrocarbon odor nor staining was observed in BB-50 or BB- I 51. The maximum TPH-cr in soil in Area B7 is 29,000 mg/kg, and the maximum TPH-d is. 9,400 mg/kg. No BTEX was detected in any of the soil samples. A sharp decrease in petroleum hydrocarbon concentrations in BB-46 at 11.5-12 feet bgs (TPH-cr decreased to 58 mg/kg, and TPH-d decreased to 27 mg/kg)provides vertical definition(to 58 mg/kg TPH-cr) to the impacted soil in Area B7. Area B7 is defined laterally by BB-45, BB-47, BB-48/BB-49, BB-52,BB-153, and BB-168. No more than 47 mg/kg TPH was detected in these bounding borings. The maximum hydrocarbon concentration in groundwater from area B-7 was 250 µg/L in BB- 49, approximately 25 feet upgradient from the pipeline alignment. However BB-48, immediately adjacent to BB-49, contained no TPH in groundwater. Along the pipeline alignment, BB-181 contained only 75 µg/l,TPH-d. No benzene was detected in the groundwater, though low concentrations of the remaining BTEX components are present. Impacted groundwater in this area is defined. 6 IA WSNHROJ8CTS1W3W3959 Shell Mountain HaneWeigh IS.g aWeighb BWelgh 8 RepanV eumnmry Fepo Jaa