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' 24 November 1997 AGE-NC Project No 95-0112 ' Page 2 of 4 ' (benzene,toluene, ethylbenzene and xylenes, BTE&X) with methyl tertiary-butyl ether(MTBE) in accordance with EPA methods 602 and 8020, and for volatile organic compounds with oxygenated compounds in accordance with EPA method 8260 3.0. FINDINGS t3 1 GROUND WATER ELEVATION AND FLOW DIRECTION ' Between July and October 1997, ground water elevation decreased an average of 0 85 feet Ground water continues to remain below the tops of the screened intervals in all monitoring wells at the site ' The relative ground water elevation data is given in Table 1 The ground water flow direction remained southerly Relative ground water elevations for October 1997 are depicted in Figure 3 ' 3 2 LABORATORY ANALYSIS OF GROUND WATER SAMPLES ' • TPH-g was detected in the ground water sample collected from MW-4 at a concentration of 430 parts per billion(ppb,reported as micrograms per liter) Benzene, ethylbenzene and xylenes were detected in MW4 at concentrations of 0 92 ppb,23 ppb and 4 9 ppb,respectively This was the first detection of petroleum hydrocarbons in MW-4 since July 1995 Petroleum hydrocarbons were not detected in any other samples collected from the site during the October 1997 monitoring event ' BTE&X were confirmed in MW-4 at concentrations of 1 8 ppb, 0 65 ppb, 25 ppb and 4 79 ppb, respectively, using EPA method 8260 Eight additional analytes, sec-butylbenzene, 1,2- ' dichloroethane(DCA), isopropylbenzene, p-isopropyltoluene, naphthalene, n-propylbenzene, 1,2,4- tnmethylbenzene, and 1,3,5-tnmethylbenzene were detected in MW-4 at concentrations as high as 17 ppb (DCA) ' Dichlorodifluoromethane was detected in MW-1 and MW-6 at concentrations of 1 7 ppb and 13 ppb, respectively A concentration of 6 3 ppb of 1,2-dichloroethane was detected in MW-5 i' Tetrachloroethene was detected in MW-6 at a concentration of 0 68 ppb No other volatile organic compounds were detected in the samples collected Oxygenated compounds, including MTBE were not detected in any ground water samples collected from the wells on the site The analytical results ' of current and previous water samples are summarized in Tables 2 and 3 The laboratory report_ (AAL, Batch No 97-1028-012) and chain-of-custody form are included in Appendix B 1 Advanced GeoEnvironmental,Inc