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1 J. N. KLEINFELDER &ASSOCIATES File: 24-2045-2/29:795 December 31, 1986 Page 2 appear to be present. The locations of the underground storage tank and proposed soil borings are shown on Plate No, 2. The locations of the proposed soil boxings may have to be revised in the field depending on the locations of surface and underground obstructions.- The soil borings will be drilled using a truck mounted drill rig equipped with 6-inch or 8-inch hollow stem augers. During the drilling, an experienced environmental geologist will classify the subsurface soils, collect soil samples, and log the borelioles. To minimize cross--contamination all augers and associated equipment will be steam cleaned prior to the drilling of each borehole. The sampling equipment will be cleaned with a trisodium phosphate wash and a distilled water rinse prior to the collectica of each soil sample. .2 Soil Sampling Proc dur s t Soil samples will be collected for chemical analysis and to complete a lithologic log. Samples will be collected at five foot intervals starting at a depth of five feet below the ground surface down to just above the iground water table. Soil samples will be collected by advancing the boring to a point immediately above the sampling depth and then driving a Modified � California Sampler linea with three brass tubes into the undisturbed soil. The sampler will then be removed from the bottom of the boring and the bottom (third) tube sealed w?th aluminum foil and tight fitting plastic caps. The sealed tube will be immediately stored in at., iced cooler. At the end of drilling operations, select soil samples will be delivered under chain-of-custody to a state/EPA.certified laboratory. The = remaining soil samples will be retained in refrigerated storage for future reference or analysis. 3.3 Oualitative, Field5creening A Photovac TIP using a photoionization detector (PIA) will be used to screen each soil sample collected from the soil borings. The PID measures total' ionizable compounds in air in parts per million by volume (ppmv) in relation to P. select standard. The standard proposed ' for this investigation , will, be s 25 or 50 ppm benzene calibration gas. Calibration ------------- -be---Performed--- -- ------- __... __._.__.. will prior-to-rise-in the--field--The-PID-field screening of-- — -the soil samples should provide a qualitative indication of the presence . of petroleum hydrocarbons. Selection of soil samples to be submitted for chemical analysis will be based on . the PID results. The screening procedure will consist of scraping the top soil layer collected in the middle tube to expose fresh soil and scanning the vapors emitted from the soil. The vapor reading will be noted and evaluated aL-the completion of the field investigation to,• select samples for chemical analyses. Rationale for selection of soil samples and analytical parameters is S—�-F, presented in Section 4.0. !� n�i IL