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4 <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 levels 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 chain -of -custody documents, and transported on ice 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, xylenes, and Methyl tert-butyl ether by DHS LUFT Methods Fuel <br />oxygenates were analyzed by EPA Method 8260A The methods of analysis for the groundwater samples are <br />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 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 (1WM) to Seaport Environmental in <br />Redwood City, California for disposal <br />