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• 3.2 Well Completion <br /> The vapor extraction well was completed with 4-inch-diameter PVC casing, screened from 15-30 <br /> feet Two-inch casing was used in the sparging well, and the screened interval is 28-30 feet Details <br /> of the well construction are shown in the boring logs <br /> 3.3 Groundwater Monitoring <br /> Groundwater monitoring took place on October 6, 1999 Upon arrival at the site, the wells were <br /> opened and allowed to equalize with atmospheric pressure A Solinst water level meter was used to <br /> measure the depth to groundwater in the wells, and the depth measurements were recorded on the <br /> Well Monitor Report(Appendix B) The data are shown in Table 1 The new wells (VT-1 and SW- <br /> 1) were dry <br /> After water depths were measured, a Grundfos submersible pump was used to purge the four <br /> monitor wells of between thirteen and sixteen gallons of water, which was stored to a DOT- <br /> approved drum in the southwest corner of the site During purging, a Corning meter was used to <br /> measure pH, conductivity, and temperature, and these parameters were recorded on the Well <br /> Monitor Report <br /> After purging, samples were collected Three 40-m1 vials were collected from each well, labeled, <br /> • and placed in a cooled ice chest These samples were later transported to Excelchem Environmental <br /> Laboratory for analysis <br /> 3.4 Laboratory Procedures <br /> Eight soil samples were transported to Excelchem and analyzed for Total Petroleum Hydrocarbons <br /> as gasoline (TPH-g) by EPA method 8015m, benzene, toluene, ethylbenzene, and xylene (BTEX) <br /> by EPA method 8020, and seven gasoline oxygenates (MTBE, ETBE, D1PE, TAME, TBA, <br /> ethanol, and methanol) by EPA methods 8260 and 8015m All samples came from within the <br /> contaminated zone (depth interval 15-30 feet) <br /> The four water samples were also transported to Excelchem, and analyzed for TPH-g, BTEX, five <br /> gasoline oxygenates, and 1,2-DCA These samples were not analyzed for methanol or ethanol <br /> 4.0 RESULTS <br /> 4.1 Soil Stratigraphy <br /> Both new borings penetrated the expected stratigraphic sequence (Appendix A) From the surface <br /> to a depth of approximately 14 feet, the site is underlain by fine-grained material The material <br /> • vanes from silt to clay in gram size and from dark brown to medium brown in color Below this <br /> 4 <br />