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i <br /> 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 <br /> for the presence of separate-phase hydrocarbons (SPH), using either an electronic indicator <br /> and a clear Teflon® bailer or an oil-water interface probe Wells not containing SPH that do <br /> not have submerged screens are then sampled without purging Wells that have submerged <br /> screens are purged of approximately three casing volumes of water (or to dryness) using a <br /> centrifugal pump, gas displacement pump, or bailer Equipment and purging method used for <br /> the current sampling event is noted on the attached field data sheets During purging, <br /> temperature, pH, and electrical conductivity are monitored in order to document that these <br /> parameters are stable prior to collecting samples After purging, water levels are allowed to <br /> partially recover Groundwater samples (both purge and no purge) are collected using a <br /> Teflon bailer, placed into appropriate EPA-approved containers, labeled, logged onto chain- <br /> 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 <br /> calculated as gasoline, benzene, toluene, ethylbenzene, xylenes, and methyl tertiary butyl ether <br /> by EPA Methods 8015 (modified), 8020, and 5030 These analyses were performed by <br /> utilizing a purge and trap extraction technique, with final detection was by gas <br /> chromatography using flame- and photo-ionization detectors The methods of analysis for the <br /> groundwater samples are documented in the certified analytical report The certified analytical <br /> report, chain-of-custody documentation, and field data sheets are presented as Attachment B <br /> 7G000-019-01/1Q98 A - 1 June 30, 1998 <br />