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• <br /> ATTACHMENT <br /> FIELD AND LABORATORY PROCEDURES <br /> Sampling Procedures <br /> 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 TeflonO bailer or an oil-water interface probe Wells not containing <br /> SPH are thea 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 California 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)by EPA Method 8015, benzene, toluene, ethylbenzene, and <br /> xylenes (BTEX)by EPA Method 8020, and total petroleum hydrocarbons calculated as diesel <br /> (TPH-d)by EPA Method 8015 In addition, groundwater samples were analyzed for the <br /> presence of methyl tertiary butyl ether(MtBE)by EPA Method 8020 Selected samples were <br /> also analyzed for oxygenates by EPA Method 8260 with the exception of methanol which <br /> was analyzed by EPA Method 8015 Duplicate water samples from Wells MW-1, MW-3, <br /> MW-7, and MW-15 were filtered by a 0 7 micron filter to remove particulates from the <br /> sample pnor to TPH-d and TPH-let analysis The methods of analysis for the groundwater <br /> samples are documented in the certified analytical report The certified analytical report, <br /> chain-of-custody documentation, and Field data sheets are presented as Attachment B <br /> 40 <br /> 920-002 2EIIQ99 DOC Apnl 6, 1999 <br />