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*.r' <br /> Mr. Harlin Knoll, REHS 2 September 6, 1991 <br /> containing petroleum hydrocarbons. During over-excavation, a Field Engineer or Scientist <br /> will visually inspect and screen the soil with a Photoionization Detector (PID) to evaluate <br /> the presence of petroleum hydrocarbons. Once a field determination is made that over- <br /> excavation is complete, verification samples will be taken to confirm that soils containing <br /> petroleum hydrocarbons have been removed. Recommended soil sampling locations are <br /> shown on Figure 1. These sampling locations take into consideration the coverage <br /> provided by the original 17 soil samples collected following removal of the underground <br /> storage tanks. <br /> Canonie will also re-excavate the southern end of the former service island to the <br /> approximate original excavation limits. The soils near the Sample No. 16 location will be <br /> over-excavated and screened as described above. Recommended soil sampling <br /> locations are shown on Figure 1. <br /> Soil samples will be retrieved from the bottom of the excavations using a backhoe. <br /> Approximately three inches of the soil will be scraped away from the surface of the soil <br /> retrieved in the backhoe bucket and a clean brass tube will be driven into the soil for <br /> sample collection. The ends of the tube will be wrapped with aluminum foil, covered with <br /> plastic caps, and sealed with a suitable tape. The brass tubes will be labeled and sealed <br /> in a ziplockTm bag. <br /> Samples will be labeled with the sample location, depth interval, date, job number, and <br /> samplers initials. Each sample will be recorded on a chain-of-custody form which will be <br /> maintained with the cooler. Samples collected will be placed immediately in a cooler with <br /> ice, or equivalent, and transported the same day to the laboratory for analysis. <br /> Soil samples will be analyzed for TPH-G and benzene, toluene, ethyl benzene, and xylene. <br /> The method of analysis and detection limits will conform to the Tri-Regional Board staff <br /> Recommendations for Preliminary Evaluation and Investigation of Underground Tank Sites <br /> (August, 1990). The samples will be analyzed overnight by Western Environmental <br /> Science and Technology's state certified laboratory located in Davis, California. The <br /> results will be available the following morning to determine if additional excavation is <br /> required. Upon approval of closure cleanup by a representative of San Joaquin County <br /> Public Health Services, Environmental Health Division, the excavation will be backfilled <br /> with imported soil and clean backfill from the original excavation. <br /> Excavated soil containing petroleum hydrocarbons will be stockpiled on-site. Two <br /> composite soil samples will be taken from the stockpile to characterize the soil for <br /> treatment (In the event the soil stockpile exceeds 50 cubic yards a maximum of four <br /> composite samples will be collected). The soil will be treated using on-site aeration. <br /> CanonleEnvironmental <br />