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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 (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 submersible pump, centrifugal <br /> pump, gas displacement pump, or bailer The equipment and purging methods used for the current sampling <br /> event are noted on the attached field data sheets During purging, temperature, pH, and electrical conductivity <br /> are monitored in order to document that these parameters are stable prior to collecting samples After purging, <br /> water levels are allowed to partially recover Groundwater samples (both purge and no-purge) are collected <br /> using a disposable Teflon@) bailer, placed into appropriate EPA-approved containers, labeled, logged onto <br /> chain-of-custody documents,and 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, xylenes <br /> (total), and MtBE using EPA Methods 8015 (modified) and 8020 The methods of analysis for the groundwater <br /> samples are documented in the certified laboratory analytical report The certified laboratory analytical report, <br /> 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 in <br /> Redwood City,California for disposal <br /> • <br />