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i 5 <br /> d , <br /> 08 December 1998 <br /> AGE-NC Project No 95-0144 <br /> ' Page 6 of 7 <br /> r <br /> ' Analytical results of ground water samples are summarized on Tables 4 and 6 Analytical results of <br /> historical ground water samples are summanzed on Table 5 The laboratory report(MAT Laboratory <br /> I D Nos 93454-93463) and chain-of-custody forms are included In Appendix D <br /> 4.0 ' SUMMARY/CONCLUSIONS 1 , <br /> r <br /> Based upon data collected from the site, AGE concludes <br /> ' Petroleum hydrocarbons and volatile organic compounds were detected In soil samples <br /> collected during the installation of MW-21, at the former location of UST No 8 TPH-d was <br /> detected in one sample collected from MW-19 at a concentration of 1 2 ppm Petroleum <br /> ' hydrocarbons were not detected in the remaining soil samples collected during the <br /> installation of MW-19 or MW-20 <br /> ' Ground water elevation decreased slightly at the site during the previous quarter Ground <br /> water was between four and six feet above the screened interval in five wells and <br /> approximately one to three feet above the screened Interval in three wells during the August <br /> ' 1998 monitoring event Ground water elevations in wells completed beneath the clay layer <br /> were approximately two feet lower than wells completed within first ground water <br /> • A clay layer, Inferred to be confining, was encountered at depths between 40 and 45 feet bsg <br /> during the advancement of borings MW-19, MW-20 and MW-21 The confining nature of <br /> this layer is suggested by ground water elevation data collected from the dual-completed <br /> wells <br /> • TPH-d was detected in the ground water sample collected from MW-13 at a concentration <br /> of 69 ppb The detected hydrocarbons may represent the down-gradient extent of water <br /> impacted from the former UST No 8 <br /> ' Petroleum hydrocarbons were not detected In water samples collected from MW-1, MW-2 <br /> and MW-4 ' <br /> • Petroleum hydrocarbons were detected in each of the six new monitoring wells Installed near <br /> ' the former UST No 8 location at concentrations as high as 9,000 ppb (TPH-g, MW-21 A) <br /> Low concentrations of MTBE or TBA were detected in each of the new monitoring wells <br /> 5.0. RECOMMENDATIONS <br /> Based upon data obtained during the third quarter of 1998 and previous sainplzng events, AGE <br /> recommends the following <br /> ' Afi anted GeoEn�ironmental,Inc <br />