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05 December 2002 <br /> . AGE-NC Project No. 97-0327 <br />' Page 3 of 5 <br />' 3.1. GROUND WATER ELEVATION AND GRADIENT <br /> The depths to ground water in wells MW-1 through MW-4 were measured between 56.40 and <br /> 5791 feet below the tops of well casings; ground water elevations in wells MW-1 through MW-4 <br /> were calculated to be between 30.96 feet (MW-2 and MW-3) and 31.07 feet (MW-1) below mean <br /> sea level (Figure 3). Ground water elevation at the site decreased an average 2.67 feet between the <br /> March 2002 and the July 2002 ground water monitoring events. Ground water flow direction for the <br /> area bound by wells MW-1 through MW-4 was generally toward the southw,crst at a gradient of 0.002 <br /> ft/ft, or approximately 11 feet per mile. ��gvm 03 <br /> 3.2. ANALYTICAL RESULTS OF MONITORING WELL WATER SAMPLES <br />' TPH-g was detected in a water sample collected from well MW-2 at a concentration of 200 <br /> micrograms per liter (gg/l).TPH-d was detected in water samples collected from wells MW-2, <br />' MW-3 and MW-4 at concentrations as high as 140 gg/l. <br />' Benzene, ethylbenzene and xylene compounds were detected in the ground water sample collected <br /> from well MW-2 at concentrations of 1.5 gg/l, 4.3 µg/1 and 7.4 gg/l, respectively. <br />' Utilizing EPA Method 8260M,MTBE was detected in samples MW-1 and MW-2 at concentrations <br /> of 0.82 gg/l and 15 µg11, respectively. TBA was detected in sample MW-2 at a concentration of 39 <br /> gg/l and 1,2-DCA was detected in the samples collected from wells MW-1, MW-2 and MW-4 at <br />' concentrations of 1.8 gg/l, 1.4 gg/l and 1.7 gg/l, respectively. <br /> No other fuel components were detected above the laboratory reporting limits. Analytical results of <br />' the ground water samples are summarized in Table 3. The laboratory reports (Castle Analytical <br /> Laboratory Reference No. 4868) and chain-of-custody forms are presented in Appendix C. <br />' 4.0. SUMMARY AND CONCLUSIONS <br />' The implications from the July 2002 ground water monitoring event are as follows: <br /> • Ground water elevation decreased approximately 2.67 feet between March 2002 and July �b3 <br /> 2002. <br /> • Ground water flow direction at the site was inferred to be toward the southv)�s`t at a gradient <br /> of 0.002 ft/ft or less. Due to the low gradient at the site, slight variations in ground water <br />' measurements or changes of recharge/discharge of the local ground water could greatly <br /> • modify ground water flow direction. <br />' Advanced GeoEnvironmental,Inc. <br /> 1 <br /> I <br /> I <br />