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�I I ' 26 June 2002 • AGE-NC Project No 95-0144 Page 4of5 ' Utilizing EPA Method 8260B,MTBE was detected in ground water samples from MW-19A,MW- 19B,MW-20B,MW-21 A and MW-21 B at concentrations ranging from 0 74µg/l in MW-21 A to 1 7 gg/1 in MW-19A TCE was not detected at or above the laboratory reporting limit In addition,no other target analytes were detected In the samples analyzed Analytical results for the second quarter 2002 monitoring event are summarized on Tables 2 and 3 Analytical results of recent and historical ground water samples are summarized on Tables 4 and 5 ' The laboratory report(MAI Lab IDs 0205255-001A through 0205255-015C)and chain-of-custody forms are Included in Appendix B ' 4.0. SUMMARY/CONCLUSIONS Based upon data collected during the ground water monitoring event, AGE concludes ' • The average ground water elevation at the site was 6 91 feet below MSL, a decrease of approximately 0 04 feet from the previous ground water monitoring event Ground water elevations in wells completed beneath the clay layer(approximately 35 to 45 feet bsg)were ' between 1 59 to 1 84 feet lower than in wells completed within first ground water • Ground water remained above the screened interval in seven of the shallow-screened wells sampled during the second quarter of 2002 ' • Ground water was inferred to flow towards the northeast in the shallow-screened wells,but was inferred to flow towards the east-southeast in deep-screened wells ' • Petroleum hydrocarbons were detected in six of the fourteen wells sampled during the May 2002 monitoring event Concentrations of TPH-g, TPH-d and TPH-mo have remained ' relatively stable since the August 2001 monitoring event • TPH-g and TPH-d were detected in wells MW-20A,MW-21A and MW-21B located within the former UST No 8 pit The plume of ground water Impacted by TPH-d is larger than the ' TPH-g plume, extending north of MW-19 and north of MW-20 • Various BTEX compounds were detected In samples MW-21A and MW-21B, the benzene ' concentration(130µg/l)is above the DHS Maximum Contaminant Level(MCL)of 10µg/1 in drinking water • Low concentrations of MTBE were detected in ground water samples collected from monitoring wells MW-I9A,MW-19B,MW-20A,MW-20B and MW-21B located north of . the former UST No 8 pit Historically,only low concentrations of MTBE and TBA have been Advanced GeoEnvironmental,Inc r