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• <br />ATTACHMENT A <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 Teflon® 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 clean submersible pump, <br />centrifugal pump, gas displacement pump, or bailer The equipment and purging methods used for the current <br />sampling event are noted on the attached field data sheets During purging, temperature, pH, and electrical <br />conductivity are monitored in order to document that these parameters are stable prior to collecting samples <br />After purging, water Ievels are allowed to partially recover Groundwater samples (both purge and no -purge) <br />are collected using a clean Teflon® bailer, placed into appropriate EPA -approved containers, labeled, logged <br />onto Cham -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, and fuel oxygenates using EPA Method <br />8260B The methods of analysis for the groundwater samples are documented in the certified laboratory <br />analytical report The certified laboratory analytical report, chain -of -custody documentation, and field data <br />sheets are presented as Attachment B <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 />