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July 16, 1998 <br />Page 2 <br />Site Assessment <br />PPSDEF Power Company <br />Project No. 98-4535 <br />Technical Approach <br />The technical approach to this project is to conduct a horizontal and vertical investigation of the tank site. <br />Hand augered soil borings will be advanced for soil and groundwater-grab sampling at the locations <br />shown on Figure 1. This should provide an assessment of the approximate contaminant impact to soil <br />and groundwater at the tank site. <br />Field Activities and Methods <br />Exploratory Soil Borings for Reconnaissance Sampling <br />Two exploratory borings will be advanced to the uppermost groundwater bearing strata to collect soil <br />samples, depth to water measurements, and collect reconnaissance groundwater samples. The <br />boreholes will be temporarily cased and developed. The ground water samples collected from the <br />boreholes will be used for a rapid reconnaissance of the site groundwater contamination. All sampling, <br />drilling, and sealing will follow the Geoscience Protocols (Attachment C) of Wright. <br />The borings will be drilled under an approved PHS-EHD permit. The boreholes will be drilled with hand <br />auger tools. All drilling equipment and sampling tools will be cleaned prior to arriving, and before leaving <br />the site. The augers will be advanced to the desired sampling depth interval, and a drive split spoon <br />sampler will be driven into undisturbed soil. Each borehole will be advanced into the aquifer and <br />temporarily cased. The water entering the borehole will be sampled using a clean bailer, and carefully <br />poured into the appropriate laboratory prepared container with minimum cavitation. The sampler will then <br />be retrieved and dissembled, and the soil filled brass liner will be sealed with Teflon® paper and plastic <br />endcaps, labeled, logged onto chain-of-custody forms and place in a chilled ice chest. <br />The boreholes will be logged using the Unified Soil Classification System under the supervision of a <br />registered geologist. Additional lithologic information will be collected to describe the subsurface geology. <br />The samples will be collected at five-foot intervals, at intervals of obvious contamination and at <br />stratigraphic features of interest. Upon completion of the borehole drilling and collection of information, <br />the boreholes will be backfilled with grout, placed from the bottom to top of the borehole leaving room to <br />replace asphalt or concrete surfaces as required. <br />Chemical Analysis <br />One sample (soil or groundwater-grab) from each of the two soil borings will be submitted for analysis to a <br />state of California certified analytical laboratory. Selected samples will be tested on a normal turn-around <br />for the following; Total Petroleum Hydrocarbons as Gasoline (TPHG), Total Petroleum Hydrocarbons as <br />Diesel (TPHD), Benzene (B), Toluene (T), Ethylbenzene (E), Xylene (X), using Modified EPA Methods <br />8015/8020, Chlorinated Hydrocarbons by EPA 8240, Metals (Cadmium, Chromium, Lead, Zinc and <br />Nickel) by EPA 6010 and PCBs by EPA Method 8080.