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18 September 1998 AGE-NC Project No 95-0173 Page 6of8 laboratory reports (Castle Analytical Laboratory Reference No 1662 and McCampbell Analytical Inc Lab I D No 91874 through 91882) and chain-of-custody forms are included in Appendix D 3 5 ANALYTICAL RESULTS OF GROUND WATER SAMPLES A total of fifteen ground water samples were submitted to DTSC-certified laboratories for analysis TPH-g was detected in ground water samples collected from wells MW-1 through MW-4, MW-6, MW-8, MW-9, MW-11, VW-1, AW-1B and AW-213 at concentrations ranging as high as 390,000 parts per billion (ppb, reported as micrograms per liter), TPH-d was detected in ground water samples collected from wells MW-i through MW-5, MW-9, MW-11, MW-12, VW-1, AW-1B and AW-213 at concentrations ranging as high as 23,000 ppb, however the laboratory reported that the chromatograms for the samples did not have typical diesel characteristics It was noted in the laboratory reports that the diesel sample container from MW-6 was broken when received by the laboratory and therefore was not analyzed Utilizing EPA Method 8020, BTEX were detected in ground water samples collected from wells �. MW-1 through MW-4, MW-6, MW-8, MW-9, MW-11, VW-1, AW-1B and AW-2B at concentrations ranging as high as 69,000 ppb(toluene, VW-I) The greatest benzene concentration was detected in the sample collected from well VW-1 at a concentration of 35,000 MTBE was not detected above laboratory reporting limits from any of the analyzed samples Utilizing EPA Method 8260, none of the fuel oxygenates were detected at concentrations equal to or greater than laboratory reporting limits However, the laboratory reported the detection of tetrachloroethene (PCE) from wells MW-10 and MW-I I at concentrations of 20 ppb and 1 6 ppb, respectively The analytical results of quarterly ground water samples are summarized in Table 3 The laboratory reports (Castle Analytical Laboratory Reference No 1677 and McCampbell Analytical Inc Lab No 92546 to 92560) and chain-of-custody forms are included in Appendix E I 4.0. SUMMARY AND CONCLUSIONS Based upon data collected during the July 1998 drilling activities and the July 1998 ground water monitoring, AGE concludes • Ground water was inferred to be flowing generally east-northeast at a calculated gradient of 0 002 ft/ft, or approximately 13 feet per mile (Figure 6) Due to the low gradient at the site, slight variations in ground water measurements or changes of recharge/discharge of the local ground water could greatly modify the inferred ground water flow direction The low gradient implies that ground water is moving quite slowly Advanced GeoEnvironmental,Inc