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Appendix A - Historical Background AGE-NC Project No 02-0964 Page 5 of 7 Hydrologic Units 1, 3, 5, 7 and 9 (HU1, HU3, HU5, HU7 and HU9) are fine-grained intervals composed of clay, silty clay, clayey silt, silt, and stiff, fine grained soil These intervals are characterized by low to moderately low pore pressure in the clay and silt, generally moderate pressures for the clayey silt to silty clay, and variable pore pressure, from moderately low to high, in the stiff, fine-grained soil Hydraulic conductivities based on SBT should range between I x 1010 to 1 x 10`m/s for clay to silt, and between. I x 10' to 1 x 10"'m/s for stiff, fine-grained soil ANALYTICAL RESULTS A total of seventeen `grab' ground water samples and two soil samples were collected from on- and off-site and submitted for laboratory analysis The concentrations of TPH-g, TPH-d and benzene were non-detect in the soil sample collected from CPTI at 55 feet bsg, however, ethylbenzene and xylene and were detected at maximum concentrations of 0 025 mg/kg TPH-g was detect in a soil sample collected from CPTI at 78 feet bsg at a concentration of 4,800 mg/kg, in addition, toluene, ethylbenzene and xylene and were detected at maximum concentrations of 350 mg/kg TPH-d and benzene were not detected in the sample from 78 feet bsg HU1 One sample (CPT5-60) was collected from off-site CPT5, target analytes were not detected in this sample HU2 One sample(CPT3-60)was collected from the westernmost boring CPT3,target analytes were not detected in this sample HU4 Samples CPT 1-100, CPT2-97,CPT3-108,CPT4-105 and CPT5-108 were collected from this HU TPH-g was detected at concentrations of 1,500 micrograms per liter(µg/1)in CPT 1-100 and 210 µg11 in CPT2-97 The BTEX compounds toluene, ethylbenzene and xylenes were detected at maximum concentrations of 14 µg/1 (CPT2-97), 13 µg/I (CPTI-100) and 80 µg/1 (CPTI-100), respectively No other analytes were detected in the samples analyzed HU5 One sample (CPT3-124)was collected from westernmost boring CPT3, target analytes were not detected in this sample HU6 Samples CPTI-124, CPT2-124 and CPT4-124 were collected from this HU TPH-g was detected in samples CPTI-124 and CPT2-124 at a maximum concentration of 14,000 µg/1 (CPT2-124),in addition,TPH-d was detected in sample CPT2-124 at 5,200µg/1 BTEX compounds were detected at maximum concentrations of 55 µg/1 benzene, 840 µg/1 toluene, 460 µg/I ethylbenzene and 2,000 4g/1 xylenes, in sample CPT2-124 In addition, the fuel additive 1,2-DCA was detected in sample CPTI-124 at 2 1 µg/1 No other analytes were detected in the samples analyzed Advanced GeoEnvironmental