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01 August 2011 <br /> AGE-NC Project No. 07-1536 <br /> Page 3 of 4 <br /> • Tertiary butyl alcohol (TBA) was reported in the ground water samples collected <br /> from wells MW-2, MW-4 and EW-1 at concentrations of 2,900 pg/I, 170 pg/I and <br /> 34,000 pg/I, respectively. <br /> No additional analytes were reported above laboratory detection limits in the ground water <br /> samples analyzed. Ground water analytical results are summarized in Table 3. <br /> Iso-concentration maps illustrating the approximate distribution of dissolved TPH-g, MTBE <br /> and TBA are depicted on Figures 5 through 7. <br /> The laboratory report(CTEL Project No. CT214-1106240, quality assurance/quality control <br /> (QA/QC) report and chain of custody forms are included in Appendix D. Depth to water <br /> measurements were uploaded to the State GeoTracker online database; the confirmation <br /> number is 5720212578. The Electronic deliverable format (EDF) file was not available at <br /> the time of report publication and will be uploaded upon receipt. <br /> 4.0. CONCLUSIONS <br /> Based upon the findings of this investigation, AGE concludes: <br /> • Ground water elevations at the site generally decreased approximately 2.59 feet in <br /> shallow zone wells, and decreased approximately 1.92 feet in deep zone wells <br /> between the first and second quarter 2011 monitoring events. <br /> • The ground water flow for the shallow water zone was consistent with historical flow <br /> directions and the hydraulic gradient was similar to previous monitoring events in <br /> the levee area. The flow direction of the deeper ground water zone was southeast <br /> and the calculated gradient were typical of previous observations at the site. <br /> • The current dissolved TPH-g plume continues to be located near wells MW-2, <br /> MW-4 and EW-1 (Figure 5). <br /> • MTBE concentrations in wells MW-2, MW-4, MW-5 and EW-1 increased slightly <br /> between the first quarter 2011 and the second quarter 2011 monitoring events. <br /> • TBA was reported in shallow zone wells MW-2, MW-4 and EW-1 located in the <br /> eastern portion of the site, at relatively high concentrations. The lateral extent of the <br /> dissolved TBA is not currently defined, downgradient of extraction well EW-1. <br /> Advanced GeoEnvironmental,Inc. <br />