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�= <br /> � 1 <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 checking 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 Ln 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 chain-of-custody documents, and transported I <br /> s' 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 xylen.;'($TEX compounds`.. Analysis <br /> for BTEX compounds was by EPA Method 5030/&020, and analy.,;for TPH- <br /> gasolinr was performed according to the DHS LUFI'method. Extraction was <br /> performed by the purge-and-trap technique with final detection by gas <br /> f 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 /> 3100102/3091 October 15,_1991 <br /> i� <br /> �i <br />