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a w The newly installed wells will be surveyed by a California State Licensed Surveyor The well casings will be surveyed to the nearest 0 01 feet in elevation to a known benchmark Organic Vapor Procedures Soil samples collected at 5-foot depth intervals during drilling will be analyzed in the field for ionizable organic compounds using a photo-ionization detector (PID) with a 10 2 eV lamp or a flame ionization detector (FID) The test procedure will involve measuring approximately 30 grams from an undisturbed soil sample, and placing this subsample in a sealed container (either a zip-lock bag or a mason far) The container will be warmed for approximately 20 minutes (in the sun), then the head-space within will be tested for total organic vapor, measured in parts per million as benzene (ppm, volume/volume) The instrument will be calibrated prior to drilling using a 100-ppm isobutylene standard (in air) and a sensitivity factor of 55, which relates the photo-ionization potential of benzene to that of isobutylene at 100 ppm The results of the field testing will be noted on the boring logs PID and FID readings are useful for indicating relative levels of contamination, but cannot be used to evaluate hydrocarbon levels with the confidence of laboratory analyses Groundwater Sampling Procedures The sampling procedure for each well consists first of measuring the water level and checking for the presence of separate-phase hydrocarbons (SPH), using either an elec- tronic indicator and a clear TeflonO bailer or an oil-water interface probe Wells not containing SPH that do not have submerged screens are then sampled without purging Wells that have submerged screens are purged of approximately three casing volumes of water (or to dryness) using a centnfugal pump, gas displacement pump, or bailer The equipment and purging method used for the current sampling event is noted on the attached field data sheets During purging, temperature, pH, and electrical conductivity are monitored in order to document that these parameters are stable prior to collecting samples After purging, water levels are allowed to partially recover Groundwater samples (both purge and no purge) are collected using a Teflon bailer, placed into appropriate EPA-approved containers, labeled, logged onto chain-of-custody documents, and transported on ice to a California State-certified laboratory Laboratory Procedures Selected soil and water samples collected will be analyzed for the presence of total petroleum hydrocarbons calculated as gasoline, benzene, toluene, ethylbenzene, and xylenes, using modified EPA Methods 8015 and 8020 Fuel oxygenates MtBE, DIPE, TBA, TAME, EtBE, 1,2 DCA, and EDB will be analyzed for by EPA Method 8260 077 43029 310/WPL.AN Nov 2000 doe November 30,2000