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i i13 July 2001 • AGE-NC Project No 96-0232 iPage 10 of 15 iinferred toward the west at an approximate gradient of 0 003 ft/ft or less (Figure 4) Ground water flow direction in the Secondary Aquifer Zone (85 to 105 feet bsg) from Flag City i Chevron monitoring wells MW-8B, MW-9B, MW-10D, MW-11C, MW-12C and MW-13C was inferred toward the west at an approximate gradient of 0 004 ft/ft or less (Figure 5) i Ground water flow direction in the Primary Aquifer Zone (130 to 150 feet bsg) from Flag City Chevron monitoring wells MW-8C, MW-9C, MW-10E, MW-11D, MW-12D and MW-13D was inferred toward the west-northwest at an approximate gradient of 0 001 ft/ft or less (Figure 6) I i3 4 2 Laboratory Results Of Ground Water Samples During the June 2001 sampling event,TPH-g and TPH-mo were detected in water samples collected i from MW-12A at concentrations of 110 µg/l and 2,300µg11, respectively, TPH-d was detected in water samples collected from wells MW-8B, MW-12A and MW-13A at concentrations of 57 µg/1, 4,300 4g/1 and 73 µg/l,respectively The laboratory indicated that the diesel range compounds in the i MW-8B, MW-12A and MW-13A sample chromatograms were significant, but did not have recognizable diesel patterns, the laboratory indicated the sample chromatogram from MW-12A contained significant oil range compounds iBenzene was detected in a water sample collected from well MW-13A at a concentration of 13 µg/l, toluene was detected in water samples collected from wells MW 12A and MW-12B at concentrations i of 18 µg/1 and 0 54 µg/1, respectively, xylene was detected in a water sample collected from MW-12A at a concentration of 0 80 µg/1 No other BTEX compounds were not detected in any samples during the June 2001 laboratory analysis MTBE was detected in water samples collected i from wells MW-1, MW-7, MW-9A,MW-11A, MW-11B and MW-13A at concentrations between 6 7 and 210µg/1 by the EPA 8020 analysis iMTBE(utilizing EPA Method 8260)was detected in water samples collected from monitoring wells MW-1,MW-7,MW-9A,MW-11A,MW-11B, MW-12A and MW-13A at concentrations between 2 4µg/1 and 190µg/l(MW-11B),isoconcentration maps displaying the estimated extent of dissolved iMTBE in First Zone and Second Zone aquifer are depicted in Figures 7 and 8 MTBE was detected in water samples collected from extraction wells EW-2, EW-4, EW-5, EW-6, EW-8, EW-9 and i EW-10 at concentrations as high as 140 µg/1 (EW-4), an isoconcentration map displaying the estimated extent of dissolved MTBE in the area of the ground water extraction wells is depicted in Figure 9 iNo other constituents of concern were detected above laboratory reporting limits in the water samples collected during the second quarter 2001 sampling event Site investigation and the current i Advanced GeoEavimamental,Inc