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i• <br /> ATTACHMENT A <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 presence <br /> of separate-phase hydrocarbons (SPH), using either an electronic indicator and a clear Teflon® bailer or an <br /> oil-water interface probe Wells not containing SPH that do not have submerged screens are then sampled <br /> without purging Wells that have submerged screens are purged of approximately three casing volumes of <br /> water (or to dryness) using a centrifugal pump, gas displacement pump, or bailer Equipment and purging <br /> method used for 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 parameters are <br /> stable prior to collecting samples After purging, water levels are allowed to partially recover Groundwater <br /> samples (both 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 State- <br /> 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 Methods 8015 <br /> (modified), 8020, and 5030 These analyses were performed by utilizing a purge and trap extraction <br /> technique, with final detection was by gas chromatography using flame- and photo-ionization detectors The <br /> methods of analysis for the groundwater samples are documented in the certified analytical report The <br /> certified analytical report, chain-of-custody documentation, and field data sheets are presented as Attach- <br /> ment B <br />