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' 17 September 2003 <br /> • AGE-NC Project No 98-0448 <br /> Page 5 of 9 <br /> 1 <br /> I , <br /> 4.0 FINDINGS <br /> AGE determined ground water flow direction and gradient from the field data collected on 17 June <br />' 2003, the contaminant impact to ground water was assessed from the laboratory data <br /> From field data collected at the SVE remediation system between 20 March 2003 and 23 June 2003, <br />' AGE determined the average TPH-g concentration and the average flow rate and calculated the <br /> approximate mass and volume of hydrocarbons removed <br />' 4 1 GROUND WATER ELEVATION AND GRADIENT <br /> I Th6 depths to ground water were measured at between 17 77 and 20 68 feet below the tops of the <br /> well casings (Table 2) Ground water elevations at the site were calculated to be between 9 01 feet <br /> (MW-7) and 1127 feet (MW-4B) below mean sea level (Table 2), ground water elevations are <br /> depicted in Figure 3 Ground water elevation at the site increased an average 0 64 feet between the <br /> March 2003 and the June 2003 ground water monitoring events <br />'• The ground water flow direction at the site was inferred to be southwest, at approximate gradients <br /> between 0 006 ft/ft and 0 016 ft/ft <br /> I <br /> 4 2 LABORATORY RESULTS OF GROUND WATER SAMPLES <br /> ITPH-g was detected in water samples collected from wells MW-1,MW-2,MW-4A and MW-4B at <br /> k' concentrations as great as 38,000 micrograms per liter (�ig/1) from MW-2 The inferred extent of <br /> I dissolved TPH-g is depicted in plan view in Figure 4 x <br /> 4 , <br /> Various BTEX compounds were detected in water samples collected from MW-I,MW-2,MW-4A <br /> I and MW-4B at concentrations as high as 4,000 µg/1 xylene (MW-2), the maximum benzene <br /> concentration was detected in the sample collected from MW-2 at a concentration of 160 µg/1 <br /> I MTBE was detected by EPA Method 8260 in a water sample collected from wells MW-4B at a <br /> concentration of 2 7 µg/1, DIPE was detected in a water sample collected from MW-1 at a <br /> concentration of 12 µg/1 <br /> No other fuel components were detected by laboratory analysis Previous and current analytical <br /> results of ground water monitoring well samples are summarized in Tables 3 and 4 The laboratory <br /> I <br /> Advanced CeoEnvironmental,Inc <br /> I <br /> s <br />