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I08 July 2004 • AGE-NC Project No 95-0184 IPage 3 of 5 s , 3 1 GROUND WATER GRADIENT AND FLOW DIRECTION The elevation of ground water in each well was calculated by subtracting the depth to ground water from the surveyed casing elevations (Table 1) Depths to ground water ranged from 35 47 feet to 36 07 feet below the tops of the well casings The average ground water elevation at the site was 23 02 feet below mean sea level (MSL), Indicating an average Increase of 147 feet below MSL ' between the Fourth Quarter 2003 and First Quarter 2004 monitoring events The ground water levels were as high as approximately 19 feet above the screened Intervals in wells MW-1 through MW-41� YV and MW-7 < 0.l-0 The ground water appears to flow generally east-northeast across much of the site under and average hydraulic gradient of approximately 0 0065 foot/foot (Figure 3 and Table 4) Well VW-5 was not Iused in calculating gradient, however the ground water elevation was calculated to be near the average ground water elevation (Appendix D) - ' 32 ANALYTICAL RESULTS OF WATER SAMPLES TPH-g was detected in all of the sampled monitoring wells, with the exception of well MW-7, at concentrations ranging from 1,100 micrograms per liter (gg/1) in MW-1 to 290,000 µg11 in_V-W-4Ai W`4 ' (Figure 3) TPH-d was detected in the sample from MW-4 at a concentration of 44,000 µg/1 A map of TPH concentrations is provided in Figure 4 ' Various BTEX compounds were detected in all,er� d�wa samples analyzed The maximum concentrations detected were 64,000 µg/l benzenes 6, (fµg/l toluene,_4,500 µg/1 ethylbenzene _(VAV- , and 22,800 gg/l total xylenes (VW-5B) A map of benzene concentrations is provided in ' Figure 5 , MTBE was detected In samples from wells MW-4, VW-2B, VW-3 and VW-4 at concentrations ' ranging from 67 gg/1 (MW-4) to 770 gg/1 (VW-4)` A map of MTBE concentrations is provided in Figure 6 ' The lead scavenger 1,2-dichloroethane (1,2-DCA) was detected in MW-2, MW-4 and VW-213 through VW-5C at concentrations ranging from 6 2 µg11 (MW-2) to 470 gg/1 (VW-4), 1,2-dibromoethane (EDB) was detected in MW-4 and VW-213 at a maximum concentration of ' 140 gg/l (VW-2B) A map of 1,2-DCA concentrations is provided in Figure 6 Six additional VOCs were detected at the following maximum concentrations naphthalene at ' 490 gg/1 (VW-2B), 1,2,4-tnmethylbenzene at 7,500 gg/i (VW-5B), n-propylbenzene at 630 µg/1 • ' v Advanced GeoEnvironmental,Inc