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Groundwater Sampling Prior to sample collection, three well volumes of groundwater were purged from seven monitoring wells (MW-1, MW-2, MW-3, MW-4, MW-6, MW-7, MW-9, and MW-10) to induce flow of groundwater representative of the surrounding formation of each well Purging and sampling was conducted using single-use polyethylene bailers or a submersible Grundfos pump Groundwater samples were collected by slowly filling the laboratory-supplied containers in such a manner as to reduce aerr, ion of the water Sample containers were completely filled so that no headspace remained Samples were placed in coolers and packed in ice to keep samples at approximately 4° C for delivery to the laboratory Field forms and sampling documentation are included in Attachment C Eight groundwater samples, including a quality control duplicate sample (MW-13) from ' MW-1, were collected and submitted to Sequoia Analytical, located in Sacramento, California The samples were analyzed for TPH-G, BTEX, and fuel oxygenates (including 1,2-DCA) by EPA Method ' 8260B ' Analytical Results The following is a summary of analytical results 0 TPH-G was detected in monitoring well MW-1 at a concentration of 120 µg/L TPH-G was not detected above laboratory reporting limits in any of the other monitoring wells during this sampling event ' 0 Benzene was detected in monitoring well MW-1 at a concentration of 2 5 µg/L Benzene was not detected above laboratory reporting limits in any of the other monitoring wells during this sampling event 0 Ethylbenzene was detected in monitoring well MW-1 at a concentration of 1 3 µg/L ' Ethylbenzene was not detected above laboratory reporting limits in any of the other monitoring wells during this sampling event 0 Total xylenes were detected in monitoring well MW-1 at a concentration of 1 1 µg/L Total ' xylenes were not detected above laboratory reporting limits in any of the other monitoring wells during this sampling event ' 0 The following constituents were not detected above laboratory reporting limits in any of the samples during this sampling event toluene, tert-butyl alcohol, MTBE, di-isopropyl ether, ethyl tert-butyl ether, tert-amyl methyl ether, 1,2-DCA, and 1,2-dibromoethane ' Benzene, ethylbenzene, and total xylenes concentrations in MW-1 were below the calculated Tier ' 1 and Tier 2 risk based screening levels for the site (Secor 2005) ' 11/11/05 \\Edmdata\pra3ec1s\231\030\003 Loekefbrd\FllefWR\Final Closure Letter doc 3 LANDAU ASSOCIATES