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September 26, 1996 <br /> Page 2 <br /> Organic Vapor Procedures <br /> Soil samples collected at 5-foot depth intervals during drilling will be analyzed in the <br /> field for ionizable organic compounds using a photo-ionization detector (PID) with a <br /> 10.2 eV lamp or flame ionization detector (FID). The test procedure will involve <br /> measuring approximately 30 grams from an undisturbed soil sample, placing this <br /> subsample in a clean glass jar, and sealing the jar with aluminum foil secured under a <br /> ring-type threaded lid. The jar will be warmed for approximately 20 minutes (in the <br /> sun), then the foil will be pierced and the head-space within the jar will be tested for <br /> total organic vapor, measured in parts per million as benzene (ppm; volume/volume). <br /> The instrument will be calibrated prior to drilling using a 100-ppm isobutylene standard <br /> (in air) and a sensitivity factor of 55 which relates the photo-ionization potential of <br /> benzene to that of isobutylene at 100 ppm. The results of the field testing will be noted <br /> on the boring logs. PID and FID readings are useful for indicating relative levels of <br /> contamination, but cannot be used to evaluate hydrocarbon levels with the confidence of <br /> laboratory analyses. <br /> Laboratory Procedures <br /> Selected soil samples collected from the soil borings will be analyzed by a California <br /> state-certified laboratory for the presence of total petroleum hydrocarbons calculated as <br /> gasoline, benzene, toluene, ethylbenzene, and xylenes using modified EPA <br /> Methods 8015 and 8020. <br /> Soil Cuttings and Purge Water <br /> Soil cuttings generated during drilling operations will be temporarily stored on and <br /> covered with plastic sheeting pending characterization and disposal. Soil cuttings will <br /> be removed by Chevron's disposal contractor to an appropriate disposal facility. Water <br /> generated during steam cleaning, and development and sampling of the new wells will <br /> be temporarily stored in DOT-approved 55-gallon drums pending transport by <br /> Chevron's disposal contractor to an appropriate disposal or treatment facility. <br /> 920-078.1 A/WPLAN <br />