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I ' 13 April 2005 AGE-NC Project No 01-0827 Page 6 of 7 ' No additional analytes were detected at or above laboratory reporting limits in the samples analyzed The laboratory report (CTEL Project No CT214-0502035), QA/QC reports and chain of custody forms are included in Appendix F GeoTracker confirmation pages of the submitted laboratory EDF ' files are included in Appendix E ' 4.0. SUMMARY AND CONCLUSIONS Based on the data collected from the site, AGE finds ' • On 31 March 2005,ground water was encountered at a depth of approximately 22 feet btoc, an increase of approximately 2 5 feet since the December sampling event ' • The ground water flow direction was inferred to be towards the east, at a gradient of approximately 0 009 ft/ft on-site and 0 01 ft/ft west of the site ' • The detections of TPH-g and BTEX compounds in the ground water sample collected from deep vapor well VW-2d demonstrate a contamination trend increase (Appendix D) Detections of TPH-g m the deepest well(MW-6)confirms the vertical extent of the dissolved ' hydrocarbons Upward fluctuations in TPH-g and BTEX concentrations during the remediation period suggest continued desorption of hydrocarbons from soil into ground water,likely due to hydrocarbon mass attached to saturated soil re-mobilized faster than the ozone is capable of destroying hydrocarbons and now is dissolved in the ground water A trend of increasing TPH-g concentrations was also documented during the start of air ' sparging and ozone-enriched sparging at the site • MTBE was the only fuel additive detected in the sample from VW-2d The concentrations of MTBE and benzene are above their respective DHS Maximum Contaminant Levels ' (MCL) for drinking water • Low ORP values, detected in the source area, demonstrate the presence of a generally ' reduced environment in the saturated zone near the source area Ideally, the introduction of oxygen rich air (ozone air sparging) in the source area should produce an oxidizing environment which will lead to a reduction in contaminant levels Dissolved oxygen ' concentrations collected from wells at the site,since operation of the ozone air sparge system commenced, indicate an adequate migration of ozone-rich sparged air into the subsurface 1 5.0. RECOMMENDATIONS Based on the findings of the remediation activities recounted in this report, AGE recommends • ' Advanced GcoEnvironmental,Inc