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Y '4 • 07 December 1999 AGE-NC Project No 95-0142 I Page 3 of 4 r s 32 ANALYTICAL RESULTS OF GROUND WATER SAMPLES I TPH-g was reported in samples collected from wells MW-6 and VW-1 through VW-4 at concentrations ranging from 65 micrograms per liter(µg/l,VW-2) to 170,000,ug/l(VW-1) Benzene was reported in samples collected from wells MW-6 and VW-1 through VW-4 at concentrations ranging from 0 68µg11(VW-2)to 25,000µg/l(VW-1) Toluene,ethylbenzene and xylenes were also ' reported in wells MW-4, MW-6 and VW-1 through VW-4 at concentrations as high as 39,000 µg/1 (toluene, VW-2) TPH-g was not reported in samples collected from MW-4 or MW-5, BTEX constituents were not reported in the sample collected from MW-5 ' MTBE was the only fuel oxygenating compound reported in water samples collected during the September 1999 monitoring event MTBE was reported using EPA method 8260 Modified in the ground water samples collected from wells MW-5, MW-6, VW-1', VW-2, VW-3 and VW-4 at concentrations of 2 7 µg/l, 6 0 ug/l, 1,000µg11, 12 4g/1, 46 ug/l, 50µg/1, respectively ' Analytical results for ground water samples analyzed by EPA Methods 8015 Modified and 8020 are summarized in Table 2 Analytical results for the ground water samples as analyzed by EPA Method ' 8260 Modified are summarized in Table 3 The laboratory report(MAI Laboratory I D Nos 22313 through 22319), quality assurance and quality control (QA/QC) report and chain-of-custody form are included in Appendix B 4.0. CONCLUSIONS 1 Based on data collected from the site, AGE concludes ' 0 Ground water flow direction appeared to be somewhat easterly, at a very low gradient • Ground water levels remained above the screened Intervals of wells MW-1, MW-2, MW-3, and therefore, these wells may not accurately characterize the shallow dissolved-phase hydrocarbon'plume ' - • TPH-g and BTEX were not reported in samples collected from the down gradient well MW- ' 5 However, low concentrations of MTBE have been reported in MW-5 five times during the last seven sampling events This may Indicate that the dissolved hydrocarbon plume is, unstable and migrating ' The highest concentration of dissolved petroleum hydrocarbons continues to be in the area of the documented release (vapor well VW-1), located immediately adjacent to the former ' location of TK1-90 UST ' Advanced GeoEnvironmental,Inc 1