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17 April 1996 <br /> ' AGE-NC Project No 95-0120 <br /> Page 5 of 7 <br /> ! fuels and 602/8020, respectively In addition, ground water samples were analyzed for methyl tertiary <br /> butyl ether(MTBE) in accordance with EPA method 602/8020 for February's monitoring event <br /> 4.0. FINDINGS <br /> ' 4 1 SOIL PROFILE <br /> ' The prevailing soil profile consisted of gray to brown, damp, fine sandy, clayey silt from surface grade <br /> to approximately 30 feet bsg Gray to brown, damp, silty clay was encountered from 30 to 45 feet <br /> bsg Gray to brown, silty, fine sand was encountered from 45 to 50 feet bsg Gray to brown, damp, <br /> ' sandy, clayey silt was encountered from 50 feet bsg to approximately 70 feet bsg Hydrocarbon odors <br /> were detected in soil from B 12 at depths between 15 to 60 feet bsg, from B 13 at depths between 30 <br /> to 65 feet bsg, and from B14 at depths between 35 to 65 feet bsg Organic vapors were detected in <br /> ' soil samples from B 12 at concentrations up to 50 parts per nullion (ppm), in B 13 at concentrations <br /> up to 376 ppm, and from B14 at concentrations up to 1,760 ppm <br /> 4 2 RELATIVE GROUND WATER ELEVATION AND GRADIENT <br /> ' The relative ground water elevations for 31 October 1995, and 08 February 1996 are depicted in <br /> Figures 6 and 7 Between October 1995 and February 1996, ground water elevation rose <br /> ' approximately 1 83 feet in MW1, 1 87 feet in MW2, and 1 78 feet in MW3 I <br /> In February 1996, the ground water gradient at the site was calculated to be 0 001 ft/ft <br /> ' (approximately 5 feet per mile) directed S 69° E (Figure 6) In October 1995, the gradient was <br /> calculated to be 0 002 ft/ft (approximately 11 feet per mile) directed N 73'E Between October <br /> 1995, and February 1996, ground water flow direction beneath the site rotated approximately 38° <br /> ' from the northeast toward the southeast <br /> ' 43 ANALYTICAL RESULTS OF GROUND WATER SAMPLES <br /> In October 1995, TPH-g was detected in samples collected from MW 1 through MW3 at <br /> concentrations of 60, 68, and 150 parts per billion (ppb, reported as micrograms per liter) No TPH- <br /> d, benzene, toluene, ethyl benzene, or xylenes, were detected from samples collected in October <br /> 1995 The analytical results from the ground water samples are included in Table 2 The laboratory <br /> ' report and chain-of-custody are included in Appendix C <br /> In February 1996, TPH-g was detected in a sample collected from MW at a concentration of 170 <br />