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ATTACHMENT B <br /> FIELD AND LABORATORY PROCEDURES <br /> Sampling Procedures <br /> Sampling equipment is thoroughly 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 (SPIT), using either an <br /> electronic indicator and a clear Teflon@O 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 are 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 chain-of-custody documents, and <br /> transported on ice to a California state-certified laboratory <br /> Laboratory Procedures <br /> The groundwater samples are analyzed for the presence of TPHg, benzene, toluene, ethylbenzene, and xylenes <br /> (total), using EPA Methods 8015 (modified)and 8020, and methyl tent-butyl ether(MtBE) and tert-butyl alcohol <br /> (TBA) using EPA Method 8260B The methods of analysis for the groundwater samples are documented in the <br /> certified laboratory analytical report The certified laboratory analytical report, chain-of-custody <br /> 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 in <br /> Redwood City,California for disposal <br />