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GEOMATRIX <br /> grab groundwater sample collected from within the affected soil at GB-1 and in the sample <br /> affected by sheen at TW-2 are likely the result of interference from non-dissolved petroleum <br /> entrained within the sample. Even with this worst-case scenario, petroleum hydrocarbon <br /> constituents (BTEX and PAHs) are not present in these samples at concentrations greater than <br /> WQOs. <br /> Soil and groundwater conditions at the Surland Homes Property can be compared to those at <br /> ' the adjacent Dividend Property (Figure 2), which was investigated by CPL due to the presence <br /> of residual OVP petroleum in soil and was granted regulatory closure by the RWQCB in 1996 <br /> ' (Geomatrix, 1995; RWQCB, 1996). Monitoring well MW-13 at the Dividend Property, like <br /> well TW-2 at the Surland Homes Property, was screened within petroleum-affected soil, <br /> contained a petroleum sheen, and had "detections"of constituents in samples collected from the <br /> well. The TPH concentrations at MW-13 were up to 10 times greater than samples affected by <br /> sheen collected from temporary well TW-2. The BTEX and PAH results are similar between <br /> MW-13 (Dividend) and TW-2 (Surland), which were non-detect or well below WQOs. <br /> QGroundwater samples collected from monitoring wells downgradient of the affected soil at the <br /> ' Dividend Property (MW-25) did not contain dissolved petroleum constituents. A similar <br /> condition exists at the Surland Homes Property where no dissolved petroleum constituents have <br /> tbeen detected in the well located just downgradient of the affected soil and sheen (TW-1). <br /> Because it was demonstrated that the petroleum-affected soil and sheen at the Dividend <br /> Property was not a source of dissolved petroleum constituents to groundwater, the RWQCB <br /> granted site closure. Likewise, because the petroleum-affected soil at the Surland Homes <br /> Property does not pose an environmental or human health risk, we recommend that the Surland <br /> Homes Property be closed by the SJCPHS. Outlined in the following section is a comparison <br /> of site conditions to the RWQCB's "Low Risk"closure criteria. <br /> M <br /> ' \\s0\dep[da[a\Doc Safe\4780.01\clsrrpt.doc 5 <br />