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ATTACHMENT A <br /> FIELD AND LABORATORY PROCEDURES <br /> Sampling Procedures <br /> Sampling equipment is thoroughly cleaned prior to each sampling event The sampling procedure for each well <br /> includes measuring the water level and checking for the presence of separate-phase hydrocarbons (SPH), using <br /> either an electronic indicator and a clear Teflon® bailer or an oil-water interface probe Wells not containing <br /> SPH that do not have submerged screens are then sampled without purging Wells that have submerged screens <br /> are 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 cham- <br /> 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, and xylenes by EPA Methods 8015 (modified) and 8020 Methyl <br /> tertiary butyl ether was analyzed by EPA Method 8260A One sample was analyzed for oil and grease using <br /> EPA Method 5520 The methods of analysis for the groundwater samples are documented in the certified <br /> laboratory analytical report The certified laboratory analytical report, chain-of-custody documentation, and <br /> 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 />