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24 August 2001 <br /> AGE-NC Project No 98-0432 <br />' Page 3 of 4 <br /> (Table 1) Ground water elevation in the momtonng wells decreased an average of 15 5 feet since the <br /> previous monitoring event in March 2001 A ground water elevation contour map for July 2001 is <br /> illustrated on Figure 3 Based on ground water elevation data, ground water flow direction is away <br /> from a ground water high projecting(edge) across the central portion of the site, transversing north <br /> to south, away from the former diesel UST area at a gradient 0 001 toward the southwest and 0 003 <br /> to the east <br /> Theicall ound water flow direction at the site is north to northwest It should be noted that at <br /> tYP Y i� , <br /> this low gradient, small measurement variations can cause significant changes in the inferred ground <br /> 1 water flow direction <br /> T <br /> s <br /> 3 2 GROUND WATER ANALYTICAL RESULTS <br /> TPH-d was detected in the ground water'samples collected from wells MW-1 and MW-2 at <br /> concentrations of 53 microgram per liter(,ug/1) and 140,ug/l, respectively MTBE was detected in <br /> four samples utilizing EPA method 8260 The highest concentration of MTBE detected was in <br /> sample MWA at 19,000 yg/l MTBE was also detected in the samples from wells MW-2 at <br /> 950 /.cg/l, MW-4 at 150 yg/l, and MW-5 at 6 7 µg/l There were no reported detections of fuel <br /> oxygenating compounds in any of the other ground water samples analyzed In addition, there were <br /> ' no reported detections of BTEX, TPH-g or other fuel additives in any of the ground water samples <br /> analyzed` " <br /> ' Analytical results from ground water samples are summarized in Tables 2 and 3 The laboratory ti <br /> reports(MAI Laboratory ID 72643 to 72648, quality assurance and quality control(QA/QC) reports <br /> and chain-of-custody forms are included in Appendix B <br /> 4.0 SUMMARY AND CONCLUSIONS <br /> The following conclusions were drawn from the results of this investigation <br /> ' During this quarter, the prevailing ground water flow direction is towards the southwest and <br /> east This inconsistent flow direction may be due to a surface water release near northern <br /> portion of the site and will be verified by further sampling events or may be due to small <br /> y' measurement variations with ground water at a very low gradient <br /> • TPH-d was detected only in MW-1 and MW-2, and was at low concentrations <br /> ' MTBE was detected in wells MW-1, MW-2, MW-4 and MW-5 during the July 2001 <br /> 4 monitoring event Three of the six ground water samples collected had reported <br /> Advanced GeoEnvoronmentai,Inc <br /> r , <br />