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A i e • 03 October 2000 AGE-NC Project No 95-0144 Page 3 of 5 0 63 and 0 91 feet in the other monitoring wells The approximate hydrauhc gradient for the August ' 2000 monitoring event was calculated to be 0 0020 ft/ft with a northerly flow direction Ground water elevation contours derived from data collected on 21 and 22 August 2000 are depicted 1 in Figure 3 Ground water was between approximately 1 34 and 6 76 feet above the screened interval in monitoring wells MW-1, MW-2, MW-4, MW-5,MW-8, MW-11, MW-1 2, MW-13 and MW-1 8 Ground water was within the screened intervals of MW-19A, MW-20A and MW-21A Ground water elevations in nested wells MW-19, MW-20 and MW-21 were between 1 14 and 2 26 feet lower in deeper screened intervals beneath a potentially confining clay layer than in the ' shallower screened intervals Data from the upper screened intervals,established in first-encountered ground water, was utilized for gradient determination ' 3 2 ANALYTICAL RESULTS OF WATER SAMPLES ' During the August 2000 monitoring event, TPH-g was detected in samples from monitoring wells MW-13, MW-21A and MW-21B at concentrations of 72 µg11, 2,900 �Lg/l and 1,200 µg11, respectively BTEX compounds were detected in samples from wells MW-13, MW-21A,MW-20B and MW-21B at concentrations as high as 210 µg/1 (benzene, MW-21A) TPH-d was detected m wells MW 19A,MW-20A,MW-21 A,and MW-2 I B at concentrations ranging from 140µg/1 to 2,900 gg/l TPH-mo was detected in monitoring well sample MW-21A at a concentration of 320 µg/1 Laboratory results of the MW-12 ground water sample were at or below the detection limit for both TPH-g and TPH-d Hydrocarbon concentrations in the other wells generally remained low or non- detect i MTBE was detected in ground water samples from wells MW-2, MW-4, MW-13, MW19A and 1 MW19B at concentrations ranging from 1 1 µg/1 to 1 5 gg/l (EPA Method 8260M) Other oxygenates were not detected in the samples collected at the site during the August 2000 monitoring event Historically, only low concentrations of MTBE and TBA have been detected intermittently ' at the site Analytical results for August 2000 are summarized on Table 2 Historical and recent analytical results from ground water samples are summarized on Tables 2 and 3 The laboratory report (MAI Laboratory I D Nos 45473-45483) and chairs-of-custody forms are included in ' Appendix B ' 4 0. SUMMARY/CONCLUSIONS ' Based upon data collected from the site, AGE concludes • Advanced GeoEnvironmentai,Inc r