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are unexpected, and far exceed the levels found in the soil above <br /> and at the interface during the placement of the wells. <br /> Although the presence of residual gasoline components in the <br /> water was not unexpected, the high levels of BTEX, (especially <br /> benzene, ) encountered is not consistent with a site that has been <br /> inactive for many years. <br /> 2. The highest levels of comtaminants have been measured in <br /> monitoring well #1, which is the farthest from the site of the <br /> removed tanks, and has not been in a consistent down-gradient <br /> position since we started sampling. Between the July and <br /> November sampling, the level of benzene measured increased by <br /> 23%. <br /> 3. Monitoring well #3, although closest to the removed UST' s, <br /> and never in a down-gradient position, has shown inureatsaug <br /> levels of benzene each time it was sampled; it increased 50% <br /> between the last two samplings. <br /> CONCLUSIONS: <br /> Based on data obtained to date, the following conclusions appear <br /> Justified; <br /> 1. The evidence for an offsite source of contamination discussed <br /> in the prior report is supported by the latest data, especially <br /> because of the increased levels of benzene detected in MW-1 & <br /> MW-3. The change in the hydraulic gradient from east Lu north- <br /> east may be the cause of some of the increase noted in MW-1, but <br /> cannot be the reason for the higher levels of benzene found in <br /> MW-3, which has never been measured in a down gradient position <br /> from the removed DST' s or pump islands. <br /> 2. Soil remediation at this time is not justified until the <br /> additional source, or sources, of contamination have been <br /> identified. <br /> 3. The placement of additional monitoring wells, as requested by <br /> the ESD, is not recommended at this time. Until the offsite <br /> investigation has been completed, and possible further sl Le <br /> assessment work is done, the locations of any future wells QannuuL <br /> be accurately determined. <br /> URECOMMENDATIONS: <br /> 1. Conduct a limited offsite investigation in an attempt to <br /> locate & identify any suspected sources of contamination. Such <br /> 2 <br />