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lie 24 April 2006 AGE-NC Project No 95-0137 Page 3 of 4 M The fuel additive MTBE was detected in monitoring well MW-8 (off-site) at a concentration of ' 200 µg/l The lead scavenger 1,2-DCA was the detected in the samples from wells MW-4, MW-9, and MW-10 at concentrations of 53 µg/l, 54 µg/l,and 71 µg/1,respectively TAME was detected in well MW-8 at a concentration of 18 µg/1 The distribution of dissolved 1,2-DCA is depicted in Figure 4 No additional contaminants of ' concern were detected in the ground water samples The analytical results are summarized in Tables 2 and 3 A copy of the laboratory report (CTEL Project Number CT214-0602080), quality assurance/quality control (QA/QC)report, and chain of custody form are included in Appendix C ' Documents confirming the upload of soil and ground water laboratory reports in electronic deliverable format (EDF) files and depth to water measurements to GeoTracker are included in Appendix D 4.0. SUMMARY AND CONCLUSIONS Based on the data collected from the site, AGE finds ' • • The average depth to ground water decreased approximately 1 18 feet between the fourth quarter 2005 and first quarter 2006 ground water monitoring events The ground water flow direction was generally northwest across the site, at a hydraulic gradient of approximately 0 001 ft/ft at the farmer UST release area to 0 039 ft/ft upgradient of the site • Dissolved petroleum hydrocarbon concentrations on-site and directly down-gradient of the former UST area were below detection limits in the first quarter 2006, except for TPH-d off-site Diesel was not detected in on-site samples for approximately two-annual monitoring cycles, with detections in well MW-4 never greater than 1,000 micrograms per liter +rV-A - ' Additionally,the detections of TPH-d did not occur in samples from well MW-2 and MW-3, the former UST location and the prior location of the most significant detections of TPH-d detections A new source of TPH-d may have been discharged off the site ' Dissolved 1,2-DCA concentrations generally have been declining, although concentrations increased since the last quarterly monitoring event in November 2005 1,2-DCA has not been ' detected in wells MW-1 and well MW-2 for six and five consecutive quarters,respectively However, the concentrations in well MW-4, MW-9, and MW-10 remain and are currently undefined by the monitoring well network ' The detections of 1,2-DCA in wells MW-4, MW-9, and MW-10 are above the DHS's Maximum Contaminant Level (MCL) of 0 5 µg/1 in drinking water The lateral extent of dissolved 1,2-DCA is undefined west and down-gradient of the site, beyond the recently installed ground water monitoring wells ' Advanced GeoEnvironmental,Inc