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• <br /> ATTACHMENT C <br /> GROUNDWATER SAMPLING FIELD AND LABORATORY <br /> PROCEDURES <br /> Sampling Procedures <br /> The sampling procedure for each well will consist of first of measuring the water level and <br /> checking for the presence of separate-phase hydrocarbons (SPH), using either an electronic <br /> indicator and a clear Teflon® bailer or an oil-water interface probe. The development proce- <br /> dure for each well consisted of pumping or bailing water from the well until the water is <br /> visibly clear, the well goes dry, or until a maximum of ten casing volumes have been <br /> removed. Equipment used for the current sampling event were noted on the field data sheets. <br /> During purging, temperature, pH, and electrical conductivity were monitored in order to <br /> document that these parameters are stable prior to collecting samples. After purging, water <br /> • levels were allowed to partially recover. Groundwater samples were then collected using a <br /> Teflon bailer, placed into appropriate EPA-approved containers, labeled, logged onto chain- <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 TPH-g, BTEX, MtBE by <br /> EPA Method 8020, and total petroleum hydrocarbons calculated as diesel (TPH-d) by EPA <br /> Method 3510. In addition, groundwater samples were analyzed for the presence of fuel <br /> oxygenates by EPA Method 8260. These analyses were performed by utilizing a purge and <br /> trap extraction technique, with final detection by gas chromatography using flame- and <br /> photo-ionization detectors. The methods of analysis for the groundwater samples were docu- <br /> mented in the certified analytical report. <br /> 920-078.1A/SOLGWAPT B-1 November24, 1997 <br />