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1 ' 27 October 2003 AGE-NC Project No 98-0450 Page 6 of 17 ' • The plume of impacted ground water above 10 µg11 of benzene is constrained on its eastern and southeaster edge of the former USTs by wells BMW-5 and somewhat on the south by well MW-5 • Significant concentrations of dissolved benzene and MTBE reside in former UST area • The ground water flow direction has been generally south and slightly southwest over the past two years of ground water monitoring ' ' The inferred pre-remediation, on-site extent of petroleum hydrocarbon-impacted ground water was presented in the Corrective Action Plan An initial mass of dissolved TPH was not generated The petroleum hydrocarbon-impacted ground water was localized beneath the northeast portion of the ' site The core of the dissolved petroleum hydrocarbons appeared to be limited to the site by wells MW-5, BMW-2 and BMW-5, as well as `grab' ground water sample from soil boring SB2 The greatest concentrations of petroleum hydrocarbon compounds detected in ground water were in the ' sample collected from former UST area Reported concentrations of BTEX compounds in ground water collected from wells exceeded the MCLS for benzene of 10 µg/l, toluene of 150 µg/l, ethylbenzene of 700 µg/1,and total xylenes of 1,750µg/l The distribution of maximum contaminate ' concentrations is depicted in Figure 4 ' 24 SENSITIVE RECEPTOR SURVEY ' A survey was performed to identify potential receptor wells near the subject property The City of Lodi Municipal Service Center and the Department of Water Resources (DWR) was contacted for the location and construction specifications for municipal wells near the site A database from the ' California Department of Water Resources (DWR), driller's well log files and a well location map prepared by the San Joaquin County Flood Control and Water Conservation District(SJCFCWCD) were examined to locate wells near the site A 2,000 foot search radius from the site was used ' Owners/residents of nearby properties of the site were contacted regarding wells near the site One active receptor well were readily located within the 2,000 foot search radius The City of Lodi Well #3, located east to northeast 1,600 feet from the site, was taken out of service due to tetrachloroethene contamination This well was subsequently destroyed The City of Well #3R, located 1,100 feet northwest of the site,was installed in 1992 to replace Well#3 The casing for Well #3R was installed from 210 feet to 340 feet in depth, with the total depth of the well boring at _ 360 feet 1 Advanced GeoEnvironmental,Inc