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09 December 2021 <br />Project No. 14-3002 <br />Page 8 of 9 <br /> <br />All soil boring locations are depicted in Figure 5. Soil boring locations where samples will <br />be collected for PCB analysis at the surface, 3, 5, 7, and 10-15 feet bsg are depicted in <br />Figures 12 through 16, respectively; and soil boring locations where samples will be <br />analyzed for TPH are depicted in Figure 18. Some soil borings will be advanced only to <br />locate waste or collect groundwater samples. Additionally, only soil collected at the <br />surface and at 3, 5, 7, 10, 15, and 20 feet bsg will be preserved for laboratory analysis; <br />wastes will be logged and described but will not be analyzed during this investigation. <br /> <br /> <br />4.3.2. Groundwater Sampling <br /> <br />Groundwater samples will be collected from 21 of the proposed soil borings. Once <br />groundwater has been encountered, five-foot long, pre-cleaned, one-inch diameter, <br />0.020-slotted temporary well screen and casing will be inserted into the borings. Each <br />groundwater sample will be extracted using a peristaltic pump and disposable ¼-inch <br />Teflon tubing through the temporary well screen. Groundwater samples will be collected <br />into laboratory-supplied, preserved 40-ml Volatile Organic Analysis (VOA) vials and into <br />1-liter amber glass and polyethylene containers. The samples will be placed in a chilled <br />container under ice for subsequent transport under chain-of-custody procedure to a <br />California ELAP-certified laboratory and selected samples will be analyzed for the <br />following constituents: <br /> <br /> TPH-g/d/o in accordance with EPA Method 8015 Modified. <br /> Dissolved lead in accordance with EPA Method 200.7. <br /> Dioxins in accordance with EPA Method E1613. <br /> <br />Proposed groundwater sampling boring locations are illustrated in Figure 5, and soil <br />boring locations depicting which constituent(s) will be analyzed at each location is <br />presented in Figure 24. <br /> <br /> <br />4.3.3. Boring Abandonment <br /> <br />All soil borings will be permanently sealed to prevent vertical migration of potential <br />contaminants. Soil borings shall be abandoned by backfilling with cement grout from the <br />total depth to surface grade. The top three to six inches of the boring abandonments will <br />be completed flush to surface grade with native soils or concrete. The EHD will be notified <br />for grout inspection at least five days prior to conducting grouting procedures. <br /> <br /> <br />4.4. CONCRETE SAMPLE COLLECTION <br /> <br />Concrete samples will be collected from two locations in the former transformer area <br />located in the southwestern corner of the power plant area. Concrete samples will be