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ATTACHMENT B <br /> FIELD AND LABORATORY PROCEDURES <br /> Sampling Procedures <br /> The sampling procedure for each well consists first of measuring the water level and checking for <br /> the presence of separate-phase hydrocarbons (SPH), using either an electronic indicator and a clear <br /> Teflon® bailer or an oil-water interface probe Wells not containing SPH that do not have <br /> submerged screens are then sampled without purging Wells that have submerged screens are <br /> purged of approximately three casing volumes of water (or to dryness) using a centrifugal pump, <br /> gas displacement pump, or bailer Equipment and purging method used for the current sampling <br /> event is noted on the attached field data sheets During purging, temperature, pH, and electrical <br /> conductivity are monitored In order to document that these parameters are stable prior to collecting <br /> samples After purging, water levels are allowed to partially recover Groundwater samples (both <br /> purge and no purge) are collected using a Teflon bailer, placed into appropriate EPA-approved <br /> containers, labeled, logged onto chain-of-custody documents, and transported on ice to a California <br /> State-certified laboratory <br /> Laboratory Procedures <br /> The groundwater samples were analyzed for the presence of total petroleum hydrocarbons <br /> calculated as gasoline, benzene, toluene, ethylbenzene, xylenes, and methyl tertiary butyl ether by <br /> EPA Methods 8015 (modified), 8020, and 5030 These analyses were performed by utilizing a <br /> purge and trap extraction technique, with final detection was by gas chromatography using flame- <br /> and photo-Ionization detectors The methods of analysis for the groundwater samples are docu- <br /> mented in the certified analytical report The certified analytical report, chain-of-custody <br /> documentation, and field data sheets are presented as Attachment B <br /> 7G500-019-0113Q98 A 1 December 11 1998 <br />