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24 May 2021 <br />Project No. 14-3002 <br />Page 18 of 23 <br /> <br />Dissolved lead was not detected above the laboratory reporting limit in the groundwater <br />samples collected from B31, B35, and B40. Total lead was detected in groundwater <br />samples collected from B46, B48, and B65 at concentrations of 0.37 mg/l, 0.00075 mg/l, <br />and 0.017 mg/l (Table 3). Two of the concentrations exceeded the MCL of 0.015 mg/l. <br />However, total lead and not dissolved lead was inadvertently analyzed in these samples. <br /> <br /> <br />DIOXIN EXTENTS <br /> <br />Limited dioxin testing was performed due to the exorbitant cost of the lab analysis. The <br />scopes of work during the previous investigations proposed dioxin analysis mainly when <br />waste was encountered. However, adequate data was collected to indicate that the glass <br />processing waste is the likely source of the dioxins. The elevated levels of dioxins were <br />detected only in waste samples, and concentrations decreased significantly in samples <br />collected at the base and beneath the waste cells (B35-14 and B40-17). Dioxin <br />concentrations exceeding the RSL of 22 pg/g are confined to the waste cells but are <br />generally undefined by the limited sampling points (Figures 15 and 17 through 21). <br /> <br />Dioxins were only analyzed in groundwater samples collected beneath waste, and all <br />dioxin concentrations were detected significantly below the MCL of 30 pg/l. The extent of <br />dioxins in groundwater exceeding the MCL is generally defined (Figure 22). <br /> <br /> <br />LEAD EXTENTS <br /> <br />Lead was not detected above the RSL of 800 mg/kg in the soil and waste samples <br />collected form AOC2. Elevated lead concentrations were detected in waste samples and <br />from soil samples collected beneath waste. However, much lower concentrations were <br />detected in soil samples outside the waste cell limits. The data indicates that the glass <br />processing waste is the likely source of the elevated lead concentrations and the extent <br />of elevated lead in soil and waste is generally defined (Table 2). <br /> <br />Lead concentrations in groundwater samples collected from B46, B48 and B65 need to <br />be confirmed for the dissolved component. But based on non-detect concentrations of <br />dissolved lead in B35, B40 and B31, collected below or adjacent to a waste cell, the extent <br />of dissolved lead is defined (Figure 22). <br /> <br /> <br />5.5.3. TPH Results <br /> <br />A total of 63 soil and waste samples (nine waste samples) and eight groundwater samples <br />were analyzed for TPH in AOC2. The samples were collected from borings B31, B33 <br />through B36, B38, B40, B41, B43 through B51, B56, B58, B63 through B68 and B79. <br />Soil and waste samples were mostly analyzed between 5 and 20 feet bsg. The following <br />is a summary of the results: <br />