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' 15 December 2003 • AGE-NC Project No 95-0173 ' Page 5 of 9 ' 41 GROUND WATER ELEVATION AND GRADIENT During the September 2003 ground water monitoring event,depths to ground water ranged between 30 20 and 33 70 feet below the tops of well casings, ground water elevations we're calculated to be between 21 58 feet(MW-8)and 23 61 feet(MW-13C)below mean sea level Generally, the ground water elevation at the site decreased an average 3 20 feet between the June 2003 and the September ' 2003 ground water monitoring events The ground water elevation data for the September 2003 ground water monitoring event is depicted ' in Figure 3 Ground water flow direction at the site was inferred to be oriented northeast across the site, at approximate gradients of 0 007 ft/ft or less, or approximately 37 feet per mile ' 4 2 LABORATORY RESULTS OF GROUND WATER SAMPLES A total of nineteen ground water samples were submitted to CAL for analysis TPH-g was detected from rune ground water samples collected from wells MW-2 through MW-4, MW-13 (A and B), AW-1 (A and B) and AW-2 (A and B) at concentrations as high as 73,000 micrograms per liter • (Vg/1) in the sample from AW-2A Various BTEX constituents were detected from 10 ground water samples collected from wells ' MW-2 through MW-4,MW-13 (A-C), AW-1 (A and B) and AW-2 (A and B) at concentrations as high as 16,000 ug/l (xylene, AW-2A) The maximum benzene concentration was detected from ' sample AW-2B at a concentration of 2,300 ug/l MTBE was only detected in the water sample collected from MW-4 at a concentration of 1 6 ug/l, ' 1,2-DCA was detected in water samples collected from wells MW-3, MW-4, MW-5, AW-1B and AW-2B at concentrations as high as 6 2 µg11 No other fuel components were detected in the samples analyzed Previous and current analytical results of ground water monitoring well samples are summarized in Tables 3 and 4, respectively The laboratory report (CAL Reference No 6143) and charm-of-custody forms are presented in Appendix C 43 RESULTS OF SOIL VAPOR EXTRACTION 1 Between 23 June 2003 and 09 September 2003, the SVE remediation system was operational for approximately 1,877 hours(Tables 6 and 7) The IAS system cycled or operated contemporaneously with the SVE system During this operational period, SVE inlet flow rates were observed to average approximately 101 cubic feet per minute, from a differential pressures observed at approximately 3 9 inches of water, with induced vacuum measurements observed between 34 and 62 inches of ' Advanced GeoEn"ron mental,Inc