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09 December 2021 <br />Project No. 14-3002 <br />Page 7 of 9 <br /> <br />If waste is encountered, trenches will be expanded laterally and vertically, if necessary, <br />to define the limits of the waste. Additionally, soil samples will be collected in native soil <br />beneath waste to assess PCB impact. Soil samples will be collected from the backhoe or <br />excavator bucket as described above if appropriate. If not appropriate, the waste locations <br />will be marked/staked at the surface. Following trenching activities, AGI will return to the <br />locations and soil samples will be collected beneath the waste using a direct-push drill <br />rig. Proposed trench locations are illustrated in Figure 4. <br /> <br /> <br />4.3. SOIL BORING ADVANCEMENT <br /> <br />AGI proposes to advance approximately (70) soil borings within and around the former <br />power plant area to delineate the extent of buried waste and to define COC-impacted soil <br />and groundwater. Soil borings will be advanced to total depths of 20 feet bsg utilizing a <br />direct-push drilling rig equipped with 1.85-inch diameter hollow probing rods advanced <br />inside 3.25-inch diameter outer casing. Proposed boring locations are illustrated in <br />Figure 5. <br /> <br /> <br />4.3.1. Soil Sampling <br /> <br />Soil samples and waste samples (if encountered) will be collected from the borings using <br />a Geoprobe soil sampling assembly loaded with 1.85-inch diameter five-foot long acetate <br />liners. Soil samples will be collected continuously between the surface and the total depth <br />of all borings. Soil and waste encountered in the borings will be visually classified by AGI <br />personnel in accordance with the USCS or type of materials encountered. Additionally, <br />soil samples will be field screened for the presence of VOCs using an organic vapor meter <br />(OVM) equipped with a photo-ionization detector (PID) calibrated to isobutylene. <br /> <br />Upon sample retrieval, the acetate sleeve will be cut open to expose the entire soil core <br />to classify the soil and inspect the core for waste. Soil samples collected at 6 inches bsg <br />and at 3, 5, 7, 10, 15, and 20 feet bsg will be hand-packed into sample jars. Sample jars <br />will be labeled with soil boring location, depth, time, date, and sampler's initials and then <br />placed in a container with sufficient ice and transported under chain-of-custody procedure <br />to a California ELAP-certified laboratory and selected soil samples will be analyzed for <br />the following constituents: <br /> <br /> Percent (%) moisture in accordance with ASTM D2216-05. <br /> PCBs (dry weight) in accordance with EPA Method 8082 (Ultrasonic EPA SW 846 <br />Method 3550C extraction method). <br /> Total petroleum hydrocarbons quantified as gasoline, diesel, and oil range <br />compounds (TPH-g/d/o) in accordance with EPA Method 8015 Modified. <br />