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° M& of Automotive August 31 1000 Toluene (T), Ethylbenzene (E) and Xylene (X), Methyl-tert-butyl-ether (MTBE) and fuel oxygenates, 1,2 Dichloroethane and Ethylene Dibromide using EPA Methods 3510/8015, 8020, 8240 and 8260 The analyses were run on a "normal" turnaround (five to ten working days) The results are tabulated and presented in Tables I and 2 below Discussion Soil Data The exploratory boring data show that very low concentrations of contaminants were observed in soil samples from l I- and 16-feet (see Figure 2) These are interpreted to be residual contaminants in soil and effectively immobile Contaminants were not observed in soil samples at 23-feet, 28-feet and 32-feet, and MTBE and oxygenate, EDB and 1,2- DCA compounds were not observed in any B-14 soil sample This is a decrease in MTBE from 420 parts per billion (ppb) in soil and 58 ppb in water from the tank pit excavation, to none detected at 1I-feet or deeper in soil The laboratory reports that TPHG in soil samples did not match the laboratory gasoline standard In our opinion these data strongly suggest a fuel absorbed in soil in a highly degraded state Shallow Groundwater Data • The groundwater data were collected at the 16-foot to 20-foot (shallow) interval and 28- foot to 32-foot (deeper) interval in the uncased borehole TPHG at 6,600 ppb and Benzene at 540 ppb were observed in the shallow interval, and TPHG at 360 ppb and Benzene at 5 9 ppb were observed in the deeper interval It is possible that water mixing in the borehole may contribute to observing contaminants in the deeper sample MTBE and oxygenates, EDB and 1,2-DCA were not observed in either groundwater sample This contaminant distribution is interpreted as displaying strong attenuation with depth, and the low overall depleted volatile content is typical of degraded petroleum plumes in our opinion The underground tank source was removed years ago These data indicate that previous soil excavation removed petroleum contaminants although low concentrations of highly degraded contaminants remain in soil and groundwater as observed in the tank pit excavation This type of contaminant distribution is typical for underground release site in our experience The previous groundwater monitoring data indicate that the dissolved plume was historically centered on the former UST pit and MW-1, and has attained a `stable" state This is interpreted to represent a dissolved plume degrading at a rate, which results in a net non-movement of the dissolved contaminants Page 4 St7/mso/cusum&m