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11 June 2002 <br /> AGE-NC Project No. 96-0229 <br /> Page 3 of 5 <br /> a. <br /> the December 2001 and the February 2002 ground water monitoring events. The ground water surface <br /> elevation at the site was within the screened intervals of wells MW-2 through MW-10A, but was <br /> approximately 17 and 19 feet above the screen intervals in wells MW-1 and MW-IOB, respectively. <br /> The ground water elevation data for MW-2 through MW-I OA during the February 2002 ground water <br /> monitoring event is depicted and contoured in Figure 3; elevation data for deep-screened wells MW-1 <br /> and MW-10B were not used to determine ground water gradient because these elevations may be <br /> LM representative of deeper ground water conditions. <br /> The general ground water gradient in the area of wells MW-I through MW-10 was calculated to be <br /> �- approximately 0.003 ft/ft or less, or approximately 15 feet per mile, and inferred to be flowing <br /> towards the northeast. <br /> 3.2. LABORATORY RESULTS OF GROUND WATER SAMPLES <br /> A total of eleven ground water samples were submitted to a DHS-certified laboratory. TPH-g was <br /> detected in water samples collected from wells MW-1, MW-2, MW-3, MW-6, MW-7, MW-9 and <br /> � MW-IOA at concentrations ranging as high as 78,000 micrograms per liter(ygll)in well MW-2. The <br /> laboratory reported each sample chromatogram as having unmodified or weakly modified gasoline <br /> chromatogram patterns. <br /> BTEX constituents were detected in ground water samples collected from wells MW-1, MW-2, <br /> MW-3, and MW-6 through MW-1 OB at a maximum concentration of 20,000 Ezgll (xylene, MW-2); <br /> the highest benzene concentration was detected in sample MW-1 at a concentration of 7,200 yg/l. <br /> ° MTBE was detected by EPA Method 8260 in ground water samples collected from wells MW-1, <br /> MW-2 and MW-6 through MW-IOB at a maximum concentration of 2,200 yg/1 (MW-6). TBA was <br /> detected in sample MW-9 at a concentration of 7.2µg/l. <br /> No other constituents of concern were detected above laboratory reporting limits in the analyzed <br /> samples. Previous and current analytical results of ground water monitoring well samples are <br /> summarized in Tables 3 and 4. The laboratory reports (McCampbell Analytical Inc. Lab I.D. No. <br /> 90528 through 90538) and chain-of-custody forms are presented in Appendix C. <br /> '! 4.0. SUMMARY AND CONCLUSIONS <br /> The implications from the findings of the February 2002 investigation are: <br /> Advanced GeoEnviranmentai,Inc. <br /> L <br />