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t <br /> r <br /> 26 November 2003 <br /> AGE-NC Project No 98-0465 <br /> Page 3'of 4 " <br />' The relative ground water elevation at the site decreased an average of 0 81 feet between the August <br /> 2003 and October 2003 monitoring events <br />' Wells MW1 through MW4 and wells MW2 through MW4, MW6 and MW7, on the adjacent site <br /> were used to Infer ground water flow direction and gradient The ground water flow direction was <br /> inferred to be northernly at the former UST location to northwest in the northwestern portion of the <br />' site The hydraulic gradient was determined to be 0 002 feet/feet or less Figure 3 illustrates the <br /> contoured ground water elevations as measured on 15 October 2003 <br /> 3 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES <br />' TPH-d and BTE&X were not detected at concentrations at or above the laboratory reporting limits <br /> in any of the ground water samples TPH-g was detected in ground water samples collected from <br /> MWl at concentrations of 500�tg/l This is the second consecutive monitoring event that TPH-g was <br />' detected in any of the four monitoring wells located on the site <br /> MTBE was detected in samples collected from MW 1 and MW3 at concentrations of 500 �L g/1 and <br /> 10 µg/l, respectively No other fuel oxygenated compounds were detected in the ground water <br /> analyses at or above laboratory detection limits Figure 4 illustrates the approximate extent of <br />' MTBE-impacted ground water <br /> Analytical results of water samples collected during August 2003 are summarized on Table 2 The <br />' laboratory report (CTEL Lab IDs 0308-138-1 through 0308-138-4), QA/QC report and chain-of- <br /> custody form are included in Appendix C <br /> 4.0. SUMMARY AND CONCLUSIONS <br />' Based on the findings from this investigation, AGE concludes <br /> • 'The ground water elevations on--site ranged from 9 91 to 10 06 feet below MSL Ground <br />' water flow was inferred to range between the north and northwest under a gradient of 0 002 <br /> feet/feet or less The ground water gradient and direction varied significantly between the <br /> August 2003 and October 2003 monitoring,events The variation is most likely due to <br />' dewatering of trenches on Country Club boulevard by the city of Stockton during the ' <br /> previous quarterly monitoring event <br /> • TPH-d and BTE&X were not detected in the ground water samples collected and analyzed <br />' during the fourth quarter 2003 <br /> Advanced GeoEnviranmental,Inc <br />