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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 the <br /> presence of separate-phase hydrocarbons (SPH), using either an electronic indicator and a clear <br /> TeflonO bailer or an oil-water interface probe Wells not containing SPH that do not have submerged <br /> screens are then sampled without purging Wells that have submerged screens are purged of <br /> approximately three casing volumes of water (or to dryness) using a centrifugal pump, gas <br /> displacement pump, or bailer Equipment and purging method used for the current sampling event is <br /> noted on the attached field data sheets During purging, temperature, pH, and electrical conductivity <br /> are monitored in order to document that these parameters are stable prior to collecting samples After <br /> purging, water levels are allowed to partially recover Groundwater samples (both purge and no purge) <br /> are collected using a Teflon bailer, placed into appropriate EPA-approved containers, labeled, logged <br /> onto chain-of-custody documents, and transported on ice to a California State-certified laboratory <br /> Laboratory Procedures <br /> The groundwater samples were analyzed for the presence of total petroleum hydrocarbons calculated as <br /> gasoline, benzene, toluene, ethylbenzene, xylenes, and methyl tertiary butyl ether by EPA <br /> Methods 8015 (modified), 8020, and 5030 These analyses were performed by utilizing a purge and <br /> trap extraction technique, with final detection was by gas chromatography using flame- and photo- <br /> ionization detectors The methods of analysis for the groundwater samples are documented in the <br /> certified analytical report The certified analytical report, chain-of-custody documentation, and field <br /> data sheets are presented as Attachment B <br /> 7G600-026-01/2Q98 A-1 September 24 1998 <br />