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r12 February 2003 AGE-NC Project No 95-0128 fPage 4 of 7 ' 3.0 FINDINGS Ground water elevations were determined by subtracting the measured depths-to-water from the surveyed casing elevations Ground water flow directions were determined by contouring the water elevations on a scaled site plan Contaminate impact to ground water samples was assessed by laboratory analysis The mass of hydrocarbons removed by ground-water extraction was calculated ' from the volume of water treated and the concentrations of contaminants from laboratory analysis ' 31 GROUND WATER ELEVATION AND GRADIENT The ground water elevation on 25 November 2002 ranged from 21 10 feet (MW-10) to 22 70 feet ' (MW-14) below mean sea level (MSL), the average ground water elevation was approximately 1 3 feet lower than the average ground water elevation during the August 2002 monitoring event The ground water table occurred within the screened interval of the shallow-screened monitoring wells(Table 1),wells MW-1 to MW-3,MW-11B and MW-12B were deeper-screened wells and are currently drowned The depth to ground water and ground water elevation data is summarized in • Table 1 The areal ground water flow direction was inferred to be northeast at gradients of between 0 003 ft/ft ' to 0 004 ft/ft An approximately 90-foot diameter cone of depression was observed at the northeast corner of the site due to drawdown of the water table by extraction well EW-1 (Figure 3), ground water gradients greater than 0 05 ft/ft were observed within this depression near EW-1 1 3 2 ANALYTICAL RESULTS OF MONITORING WELL GROUND WATER SAMPLES ITPH-g was detected in ground water samples MW-4, MW-5 and VW-1 at concentrations of 1,400 micrograms per liter(µg/1), 17,000 µg/l, and 5,800 µg/1,respectively, TPH-d was detected in ' the same samples plus MW-6 at concentrations of 770 µg11, 7,200 µg/l, 5 0 µg/1 (MW-6) and 2,800 µg/l, respectively Various BTEX compounds were detected in samples MW-1 through MW-5 and VW-1,at maximum concentrations of 140 µg/1 benzene, 1,900 µg/1 ethylbenzene and 4,100 µg/1 xylenes from sample MW-5 and 320 µg/1 toluene from sample VW-1 MTBE was detected in ground water samples MW-2 through MW-6, MW-8, MW-11A, MW I IB, MW12A, MW-12B, MW-15 and VW-1 at concentrations ranging from 0 67 µg/1 in MW-6 to ' Advanced GeoEnviroamental Inc t