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1 • 30 July 1999 <br /> AGE-NC Project No 95-0144 <br /> ' Page 3 of 4 <br /> was within the screened intervals of MW-19A, MW-20A and MW-21A <br /> ' Ground water elevations in wells MW-19, MW-20 and MW-21 were between 136 and 2 23 feet <br /> lower in the Iower screened intervals beneath the confining clay layer than in the upper screened <br /> ' interval. Data from the upper screened interval, established in first-encountered ground water was <br /> used for gradient determination <br /> 1 <br /> 3 2 ANALYTICAL RESULTS OF WATER SAMPLES <br /> During the May 1999 monitoring, TPH-g was detected in monitoring wells MW-1, MW-2, MW-4, <br /> MW-20B,MW-21 A and MW-21 B at concentrations ranging from 63 parts per billion(ppb,reported <br /> ' as micrograms per liter) to 5,200 ppb BTEX compounds were detected in each well at <br /> concentrations as high as 170 ppb (benzene, MW-21 A) TPH-d was detected in wells MW-19A, <br /> MW-20A, MW-20B,MW-21A and MW-21B at concentrations ranging from 130 ppb to 8,900 ppb <br /> ' TPH-mo was detected in MW-21A at a concentration of 680 ppb Detected concentrations of <br /> hydrocarbons in ground water remained relatively stable during the last quarter Oxygenates were <br /> not detected at the site during the May 1999 monitoring event Historically,only low concentrations <br /> of MTBE and TBA have been detected intermittently at the site Analytical results for May 1999 are <br /> summarized on Table 2 Analytical results of historical ground water samples are summarized on <br /> ' Table 3 The laboratory report (MAI Laboratory I D Nos 10559-10568) and chain-of-custody <br /> forms are included in Appendix B <br /> ' 4 0. SUMMARY/CONCLUSIONS <br /> ' Based upon data collected from the site, AGE concludes ' <br /> • Ground water elevation increased slightly at the site during the previous quarter Ground <br /> water remained above the screened interval in four of the shallow wells sampled during the <br /> current quarter Ground water elevations in wells completed beneath the clay layer were <br /> ' lower than in wells completed within first ground water <br /> • Petroleum hydrocarbons were detected in each well sampled during the May 1999 <br /> monitoring event Concentrations of hydrocarbons generally increased at the site between <br /> February and May 1999 <br /> • Oxygenates were not detected in the samples collected during the May 1999 monitoring <br /> event <br /> ' Advanced GeoEmiron mental,Inc <br /> 1 <br />