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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 <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 centrifugal pump, gas <br /> displacement pump, or bailer The equipment and purging method used for the current sampling event are <br /> noted on the attached field data sheets During purging, temperature, pH, and electrical conductivity are <br /> 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 Teflon® bailer, placed into appropriate EPA-approved containers, labeled, logged onto chain-of- <br /> 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 (TWNI) to Seaport Environmental in <br /> Redwood City,California for disposal <br />