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1 <br /> ' ATTACHMENT A <br /> FIELD AND LABORATORY PROCEDURES <br /> Sampling Procedures <br /> L The sampling procedure for each well consists first of measuring the water level and <br /> checking for the presence of separate-phase hydrocarbons (SPH), using either an electronic <br /> indicator and a clear Teflon® bailer or an oil-water interface probe Wells not containing <br /> ' SPH are then purged of approximately three casing volumes of water (or to dryness) using a <br /> centrifugal pump, gas displacement pump, or bailer Equipment used for the current <br /> sampling event is noted on the attached field data sheets During purging, temperature, pH, <br /> 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 <br /> recover Groundwater samples are collected using a Teflon bailer, placed into appropriate <br /> EPA-approved containers, labeled, logged onto chain-of-custody documents, and transported <br /> on ice to a Califorma State-certified laboratory <br /> Laboratory Procedures <br /> The groundwater samples were analyzed for the presence of total petroleum hydrocarbons <br /> calculated as gasoline(TPH-g),benzene, toluene, ethylbenzene, and xylenes(BTEX)by <br /> EPA Method 8020, and total petroleum hydrocarbons calculated as diesel (TPH-d)by EPA <br /> Method 3510 In addition, groundwater samples were analyzed for the presence of methyl <br /> tertiary butyl ether(MtBE)by EPA Method 8020 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 <br /> the groundwater samples are documented in the certified analytical report The certified <br /> analytical report, chain-of-custody documentation, and Field data sheets are presented as <br /> Attachment B <br /> f <br /> 920-002 2D/2Q98 DOC July 30, 1998 <br />