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LLEEDSHILL•HERKENHOFF. INC. <br /> during Task 2, water/sludge samples will be collected from appropriate <br /> sanitary sewer manholes, again to establish background sewage inflow water <br /> quality conditions from upgradient sources. <br /> Confirmation samples will be obtained from previously sampled locations to <br /> ensure that the sanitary sewer conveyance system is not a continuing source <br /> of contamination. Approximately four (4) soil samples will be collected by <br /> j slant boring beneath selected sanitary sewers. Every effort will be made to <br /> collect these .samples from the material beneath the sanitary sewer (worst <br /> i case condition) ; however, our success will depend on the accuracy of the <br /> available "as-built" drawings. One soil sample each will be collected from <br /> the following locations: <br /> - between previously sampled MH#2 and #3; <br /> - west of MH#3; <br /> between previously sampled MH#1 and #4; and, <br /> between MH#1 and LV Well #1. <br /> If these soil samples show no contamination, it will imply that the material <br /> in and around the sewer pipeline is not a continuing source of contamina- <br /> tion. <br /> In addition, several soil samples have been collected from beneath the <br /> concrete slab of the former Norge Cleaners building. These samples were <br /> collected in the vicinity of former floor drains located at the east end of <br /> the building. These analytical results indicated detectable PCE concentra- <br /> tions in all samples. (Analytical results were forwarded in a separate <br /> transmittal .) To determine whether a similar situation exists at both <br /> Finest Care and Village Cleaners, it is proposed to install three, 3-inch <br /> diameter holes through the existing concrete slabs of these facilities and <br /> collect samples from depths of 0 to 4 inches and 18 to 24 inches, and ana- <br /> lyze for PCE. These samples will be collected in the vicinity of existing <br /> floor drains serving the solvent filtration unit, and the solvent recovery <br /> unit ("cooker") . <br /> Task 2: Evaluation of Existing Data <br /> As discussed in our original Workplan, information available from various <br /> agencies, including but not limited to the San Joaquin County Public Works <br /> Department and San Joaquin Local Health Department, will be obtained and <br /> evaluated. Chevron USA, Inc. will also be contacted in an attempt to obtain <br /> additional data. Information collected and evaluated as discussed in Tasks <br /> 1 and 2 will be used to better focus or redefine specifics of this Workplan. <br /> Depending on availability and applicability of data from Chevron, LH's <br /> proposed monitoring well locations may be adjusted. Prior to implementing <br /> the Phase I field work, final proposed monitoring well locations will be <br /> provided to the Central Regional Water Quality Control Board (RWQCB) . <br /> • -2- <br />