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k <br /> ATTACHMENT A <br /> FIELD PROCEDURES AND LABORATORY ANALYSIS <br /> Groundwater Sampling Procedures <br /> The groundwater sampling procedure consisted of first measuring the water <br /> level in each well with an electronic water level indicator, and checkiog each <br /> well for the presence of separate-phase hydrocarbons using a clear Teflon <br /> bailer. If the wells did not contain separate-phase hydrocarbons, they were <br /> then purged of approximately four casing volumes of water (or to dryness) <br /> using a 2-inch diameter centrifugal pump. During purging, temperature, pH, <br /> and electrical conductivity were monitored in order to document that these <br /> parameters were stable prior to collecting samples. After purging, the water <br /> levels were allowed to partially stabilize. Groundwater samples were <br /> collected using a Teflon bailer, placed into appropriate EPA-approved <br /> containers, labelled, logged onto ebain-of-custody documents, and transported <br /> on ice to a State-certified laboratory. Chain-of-custody documentation is <br /> attached. <br /> Laboratory Analysis <br /> Groundwater samples were analyzed in the laboratory for the presence of <br /> total petroleum hydrocarbons calculated as gasoline (TPH-gasoline), and <br /> benzene, toluene, ethylbenzene, and xylenes (BTEX compounds). Analysis <br /> for BTEX compounds was by EPA Method 5030/8020, aI'd analysis for TPH- <br /> gasoline was performed according to the DHS LUFT method. Extraction was <br /> performed by the purge-and-trap technique with final detection by gas <br /> chromatography using a flame-ionization detector and a photo-ionization <br /> detector. Groundwater samples were also analyzed for total petroleum <br /> hydrocarbons calculated as diesel by modified EPA method 8015. All <br /> analyses were performed by a State-certified laboratory. <br /> 1 <br /> 3100102/3091 0d0ber 15,1991 <br />