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gg <br /> w - <br /> 1. H. KLEINFELDER &ASSOCIATES <br /> To minimize the potential for cross-contamination, all augers and <br /> associated equipment were steam cleaned prior to use and between borings. <br /> Thee sampler was also cleaned with a trisodium phosphate wash and a <br /> distilled water rinse between subsequent samples. All brass tubes were <br /> new and were steam cleaned prior to their use. <br /> is <br /> All samples were collected under the direct field supervision of a <br /> Kleinfelder geologist. The geologist was also responsible for classifying <br /> the subsurface soils using the Unified Soil. Classification syste. and <br /> preparing a field log of the boreholes. The Unified Soils Classification <br /> system is displayed on Plate 3 and the soil encountered in the borings are <br /> described on the drilling legs, Platb3 4 through 26. <br /> 3.3 QUALITATIVE FIELD SCREENING <br /> #Y <br /> To provide a qualitative indication of contamination, a portable organic <br /> vapor detection instrument was utilized in the investigation. The <br /> instrument is a Photovac TTP utilizing a 10.6 eV photoionization lamp. A <br /> 25 ppm benzene calibration gas was sei'ated and.used to set a reference <br /> for relative comparison of the field; raadings. Calibration of the <br /> instrument using the reference gas was conducted prior to and during its <br /> field use. <br /> The field screnning consisted of scraping the top soil layer of the sample ; <br /> collected in the middle tu'e to expose ..fresh soil, and measuring the <br /> relz_ive vapor concentration indicated by the PID. These qualitative <br /> " measurements provided relative indications of soil, contamination and were I <br /> used to select apparently contaminated samples for chemical analysis. <br /> Results of the PID screening are summarized on Table 1. <br /> 3.4 SOIL SAMPLE ANALYSIS <br /> 4 <br /> Forty-four suil samples collected at 11, 16, 21, and 26 feet below the <br /> sy ground surface from each of the 11 boreholes, were submitted to California <br /> _Analytical Laboratories,- Inc. for chemical analysis.- Each sample was T - <br /> analyzed for total petroleum hydrocarbons by modified EPA Method 8415. <br /> 38-87-43 . <br /> r <br />