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! 06 October 1997 AGE-NC Project No 95-0144 Page 2 of 4 ! The samples were analyzed for total petroleum hydrocarbons quantified as gasoline(TPH-g), diesel (TPH-d), and motor oil (TPH-mo) in accordance with EPA Method 8015 modified for each hydrocarbon range, for volatile aromatic compounds (benzene,toluene, ethylbenzene and xylenes, ! BTE&X) with methyl tertiary-butyl ether (MTBE) in accordance with EPA Method 602, and fol oxygenated volatile organics in accordance with EPA Method 8240/8260 3.0 FINDINGS ' 3 1 RELATIVE GROUND WATER ELEVATION AND GRADIENT The relative elevation of ground water in each well was calculated by subtracting the depth to water from the surveyed casing elevation(Table 1) Ground water elevation increased an average of 0 31 feet between May and August 1997 The approximate hydraulic gradient for the current monitoring ' period was calculated to be 0 004 ft/ft on the northern portion of the monitored area, and 0 015 ft/ft on the southern portion of the monitored area, both with a northerly flow direction Ground water elevation contours derived from data collected on 05 August 1997 are depicted in Figure 3 32 ANALYTICAL RESULTS OF WATER SAMPLES During the August 1997 monitoring, TPH-g was detected in well MW-1 at a concentration of 65 parts per billion (ppb, reported as micrograms per liter), TPH-d was detected in wells MW-2, MW-5 ' and MW-13 at concentrations of 130 ppb, 71 ppb and 64 ppb, respectively TPH-mo was not detected in samples collected during the August 1997 monitoring event Ethylbenzene and xylenes were detected in the sample collected from MW-1 at concentrations of 6 6 ppb and 4 7 ppb, respectively Petroleum hydrocarbons were not detected in samples collected ! from wells MW-4, MW-8, MW-11, MW-12 or MW-18 Analysis of the ground water samples by EPA Method 8240/8260 detected similar concentrations ' of toluene and xylenes as did EPA Method 8020, and also detected chloroform at concentrations of 1 1 ppb, 3 5 ppb and 14 ppb in MW-2, MW-13 and MW-18, respectively Oxygenated volatile organic compounds were not detected in any ground water samples ! Analytical results of ground A ater samples are summarized on Tables 2 and 3 The laboratory report (MAI Laboiatory I D Nos 79499 - 79507) and chain-of-custody forms are included in Appendix B Adtairced CeoEnNrronmental,Inc