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0 <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 <br />includes measuring the water level and checking for the presence of liquid -phase hydrocarbons (LPH), <br />using either an electronic indicator and a clear Teflon® bailer or an oil -water interface probe Wells not <br />containing LPH that do not have submerged screens are then sampled without purging Wells that have <br />submerged screens are purged of approximately three casing volumes of water (or to dryness) using a <br />clean submersible pump, centrifugal pump, gas displacement pump, or bailer The equipment and <br />purging methods used for the current sampling event are noted on the attached field data sheets During <br />purging, temperature, pH, and electrical conductivity are monitored in order to document that these <br />parameters are stable prior to collecting samples After purging, water levels are allowed to partially <br />recover Groundwater samples (both purge and no -purge) are collected using a clean Teflon® bailer, <br />placed into appropriate EPA -approved containers, labeled, logged onto chain -of -custody documents, and <br />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, <br />Xylenes (total), and MtBE using EPA Methods 8015 (modified) and 8021, and fuel oxygenates using EPA <br />Method 8260B 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 <br />water tank The water is transported to ARCO's holding facility in West Sacramento, California, for <br />temporary storage Water is then transported by Integrated Waste Management (IWM) to Seaport <br />Environmental in Redwood City, California for disposal <br />