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concentrations suggestive of a vapor encroachment condition (VEC) related to the residential <br /> structures south of the Site. <br /> Decision Statement: <br /> Conduct a soil gas assessment by analyzing five-foot deep soil gas samples collected from shallow <br /> unsaturated zone soils along the southern boundary of the Site immediately south and southwest <br /> of the Quality Cleaners. This work will be conducted to assess the potential for the lateral <br /> migration of PCE and TCE in soil gas and to assess the potential for VI into the residential <br /> structures along the southern boundary of the subject property. <br /> Inputs to Decision: <br /> Qualitative evaluation of air permeability of shallow unsaturated soils, depth, lateral distance of <br /> residential structures and residential exposure scenarios. <br /> Boundaries of the Task Investigation: <br /> Geographical: An area approximately 100 foot in length along the southern boundary of the Site <br /> approximately 50 feet south of the Quality Cleaners <br /> Temporal:This task will be conducted as the first work related to implementing the Workplan and is <br /> anticipated to be conducted in July 2016. <br /> Decision Rule.- <br /> If VOCs concentrations in the proposed soil gas samples contain VOCs at concentrations greater <br /> than applicable residential screening levels, than the following may apply: <br /> • Shallow soil gas samples proximate to the residential structures. <br /> 1.4.3 PCE Groundwater Plume Assessment <br /> Problem Statement: <br /> Limited groundwater sample data indicate that PCE was present in a groundwater sample located <br /> approximately 100 feet southwest of the dry cleaning machine location. A screening level <br /> assessment of groundwater in May 2015 suggests the lateral extent of the plume may be limited <br /> to groundwater to the south-southwest of the dry cleaners suite. <br /> Decision Statement: <br /> Assess the potential lateral extent of PCE and other VOCs in groundwater. Assessment would <br /> consist of installing and monitoring groundwater monitoring wells. <br /> The vertical characterization of the PCE plume will occur following the confirmation of the <br /> groundwater flow direction using continuously cored soil borings and the collection of grab <br /> Sampling and Analysis Plan <br /> Tracy Corners Shopping Center <br /> 3225 North Tracy Boulevard <br /> Tracy,California 95376 <br /> Partner Project Number SM14-129814 <br /> Docket Number HAS-VCA 14/15-108 <br /> August 15,2016 <br /> Page 5 <br />