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l5� <br /> • <br /> ATTACHMENT A <br /> FIELD AND LABORATORY PROCEDURES <br /> Sampling Procedures <br /> The sampling procedure for each well consists first of measuring the water level and checking for the presence <br /> of separate-phase hydrocarbons (SPE), using either an electronic indicator and a clear Teflon® baiter or an oil- <br /> water interface probe Wells not containing SPH that do not have submerged screens are then sampled without <br /> purging Wells that have submerged screens are purged of approximately three casing volumes of water(or to <br /> dryness) using a clean centrifugal pump,gas displacement pump,or bailer The equipment and purging method <br /> used for the current sampling event is noted on the attached field data sheets During purging,temperature,pH, <br /> and electrical conductivity are monitored in order to document that these parameters are stable prior to <br /> collecting samples After purging, water levels are allowed to partially recover Groundwater samples (both <br /> purge and no purge) are collected using a clean Teflon bailer, placed into appropriate EPA-approved <br /> containers, labeled, logged onto chain-of-custody documents, and transported on ice to a California State- <br /> 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 LUFf Methods Fuel <br /> oxygenates were analyzed for by EPA Method 8260B The methods of analysis for the groundwater samples <br /> are documented in the certified analytical report The certified analytical report, chain-of-custody documenta- <br /> tion,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 (IWM) to Seaport Environmental in <br /> Redwood City,California for disposal <br />