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! 14 July 2006 . AGE-NC Project No 95-0137 ' Page 3 of 4 The fuel additive MTBE was detected in monitoring well MW-8 (off-site) at a concentration of ' 130 µg/1 The lead scavenger 1,2-DCA was the detected in the samples from off-site wells MW-9 and MW-10 at concentrations of 22 µg11 and 76 µg11, respectively TAME was detected in well MW-8 at a concentration of 11 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 CT214-0605138), quality assurance/quality control (QA/QC) report, and chain of custody form are included in Appendix C ' Documents confirming the upload of 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 0 8 feet between the first and ' second quarters 2006 ground water monitoring events The ground water flow direction was generally northwest across the site, at a hydraulic gradient of approximately 0 0001 ft/ft at the former UST release area to 0 04 ft/ft upgradient of the site ry ' • Dissolved petroleum hydrocarbon concentrations on-site and directly down-gradient of the former Ripon Farm Service UST area were below detection limits in the second quarter ' 2006 • Dissolved 1,2-DCA concentrations have declined on-site to non-detectable levels(MW-4), ' although concentrations in wells MW-9,and MW-10 remain and are currently undefined by the monitoring well network The detections of 1,2-DCA in wells 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 to northwest and down-gradient of the site, beyond the recently installed ground water monitoring wells y 5.0. RECOMMENDATIONS Based on the findings of the environmental activities recounted In this report and previous investigations, AGE recommends • Continuation of the quarterly ground water monitoring program, the next monitoring event • will be scheduled for the third quarter 2006 with the removal of BTEX, fuel oxygenates, Advanced GeoEnvironmentat,Inc