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27 June 2002 <br /> . AGE-NC Project No 98-0448 <br /> Page 4 of 8 <br /> I4.0. FINDINGS <br /> AGE determined ground water flow direction and gradient from the field data collected on 12 <br /> February 2002, the contaminant impact to ground water was assessed from the laboratory data <br /> From field data collected at the SVE remediation system during the first quarter 2002, AGE <br /> determined the average TPH-g concentration and the average flow rate and calculated the <br /> approximate mass and volume of hydrocarbons removed <br /> I4 1 GROUND WATER ELEVATION AND GRADIENT <br />' The depths to ground water in wells MW-1, MW-4A, MW-4B, MW-6 and MW-8 were measured <br /> between 18 06 and 19 31 feet below the tops of the well casings (Table 2) Ground water elevations <br /> at the site were calculated to be between 8 86 feet(MW-7) and 10 30 feet (MW-5)below mean sea <br /> level (Table 2), ground water elevations are depicted in Figure 3 Ground water elevation at the site <br /> increased an average 1 79 feet between the November 2001 and the February 2002 ground water <br /> • monitoring events <br /> The general ground water gradient at the site was calculated to be approximately 0 02 ft/ft or less, <br /> or approximately 125 feet per mile, directed towards the southwest (Figure 3) <br /> 4 2 LABORATORY RESULTS OF GROUND WATER SAMPLES <br /> TPH-g was detected in water samples collected from wells MW-1, MW-2, MW-4A, MW-4B and <br /> MW-6 at concentrations as high as 34,000 micrograms per liter (ug/1), the highest TPH-g <br /> concentration In first water was detected from MW-4B The laboratory reported that the sample <br /> chromatograms all contained significant unmodified or weakly modified gasoline The inferred <br /> Iextent of dissolved TPH-g is depicted in plan view in Figure 4 <br /> Various BTEX compounds were detected in water samples collected from MW-1, MW-2, MW-4A, <br /> MW-4B and MW-6 at concentrations as 1mgh as 5,500,ug/l xylene(MW-2), the maximum benzene <br /> concentration was detected in the sample collected from MW-4B at a concentration of 4,100,Ag/1 <br /> IMTBE was detected in water samples collected from MW-4B at a concentration of 28 ,ug/l, <br /> respectively, DIPE was detected in a samples collected from MW-1 and MW-4B at concentrations <br /> of 2 1 ,ugn and 6 2141,respectively No other fuel components were detected by laboratory analysis <br /> Previous and current analytical results of ground water monitoring well samples are summarized in <br /> Advanced GeoEnvironmental,Inc <br /> I <br />