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' 06 April 2005 AGE-NC Project No 98-0448 iPage 5 of,9 i4.0. FINDINGS AGE determined ground water flow direction and gradient from the field data collected on 07 iDecember 2004, the contaminant Impact to ground water was assessed from the laboratory data - From field data collected at the SVE remediation system between 23 September 2004 and 22 i December 2004, AGE determined the average TPH-g concentration and the average flow rate and calculated the approximate mass and volume of hydrocarbons removed i4 1 GROUND WATER ELEVATION AND GRADIENT i On 07 December 2004,the depths to ground water were measured at between 20 27 feet and 23 31 feet below the tops of the well casings(Table 2) The December 2004 ground water elevations at the site were calculated to be between 11 23 feet(MW-3)and 14 18 feet(MW-4B)below mean sea level i (Table 2), ground water elevations are depicted on Figure 3 Generally, ground water elevation at the site decreased an average of 0 48 foot between the September 2004 and the December 2004 ground water monitoring events i The December 2004 ground water flow direction at the site was inferred to be southwest, at an i approximate gradient of 0 010 ft/ft (Figure 3) The flow direction this quarter was consistent with historical flow directions i4 2 LABORATORY RESULTS OF GROUND WATER SAMPLES i During the December 2004 monitoring events, TPH-g was only detected in the water sample collected from well MW-2 at a concentration of 1,300 micrograms per liter (ggh) The inferred extent of dissolved TPH-g during the December 2004 ground water monitoring event is depicted in iplan view in Figure 4 Toluene,ethylbenzene and total xylenes were detected at concentrations of 12 µg/1 toluene, 120 gg/l iethylbenzene and 720 µg/1 xylenes,respectively, from well MW-2,benzene was not detected in any water samples iNo other fuel components were detected by laboratory analysis Previous and current analytical results of ground water monitoring well samples are summarized in Tables 3 and 4 The laboratory i reports (Cal Tech Environmental Laboratories I D 0412-050), quality assurance/quality control (QA/QC)and chain of custody forms are presented in Appendix C,GeoTracker confirmation pages of the submitted laboratory electronic deliverable format (EDF) files are included in Appendix G ' Advanced GeoEnvironmental,Inc