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ATTACHMENT B <br /> FIELD AND LABORATORY PROCEDURES <br /> Sampling Procedures <br /> Sampling equipment is throughly cleaned prior to each sample The sampling procedure for each well includes <br /> measuring the water level and checking for the presence of separate-phase hydrocarbons (SPH), using either an <br /> electronic indicator and a clear TeflonO bailer or an oil-water interface probe Wells not containing SPH that <br /> do not have submerged screens are then sampled without purging Wells that have submerged screens are <br /> purged of approximately three casing volumes of water (or to dryness) using a centrifugal pump, gas <br /> displacement pump, or bailer The equipment and purging method used for the current sampling event is noted <br /> on the attached field data sheets During purging, temperature,pH,and electrical conductivity are monitored in <br /> order to document that these parameters are stable prior to collecting samples After purging, water levels are <br /> allowed to partially recover Groundwater samples (both purge and no purge) are collected using a Teflon <br /> bailer,placed into appropriate EPA-approved containers, labeled, logged onto cham-of-custody documents,and <br /> transported on lee 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, and xylenes by EPA Methods 8015 (modified) and 8020 Tert butyl <br /> alcohol and methyl tertiary butyl ether were analyzed using EPA Method 8260A The methods of analysis for <br /> the groundwater samples are documented in the certified laboratory analytical report The certified laboratory <br /> analytical report,chain-of-custody documentation,and field data sheets are presented as Attachment C <br /> Purge and Rinsate Water Disposal <br /> Water generated during well sampling and equipment cleaning is pumped into a SECOR truck mounted water <br /> tank The water is transported to ARCO's holding facility in West Sacramento,California,for temporary <br /> storage Water is then transported by Integrated Waste Management(IWM)to Seaport Environmental to <br /> Redwood City,California for disposal <br />