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1 i ' 29 July 2005 AGE-NC Project No 01-0827 ' Page 4 of 5 ' 3 2 ANALYTICAL RESULTS OF GROUND WATER SAMPLES Based on analysis of the 15 June 2005 ground water samples, TPH-g was detected in the ground ' water samples collected from wells VW-2d and MW-6 at concentrations of 360 micrograms per liter (µg/1) and 190 µg/1, respectively Of the BTEX compounds, only 8 6 µg/1 of ethylbenzene and 7 4 µg/1 of xylenes were detected in the ground water sample collected from well MW-6 No ' additional analytes were detected at or above laboratory reporting limits in the samples analyzed The analytical results are summarized in Tables 2 and 3 A copy of the laboratory report (CTEL ' Project No CT214-0506158), quality assurance/quality control (QA/QC) reports, and chain of custody forms are included in Appendix D GeoTracker confirmation pages of the submitted laboratory electronic deliverable format (EDF) files are included in Appendix E I 4.0. SUMMARY AND CONCLUSIONS ' Based on the data collected from the site AGE finds • • On 15 June 2005, ground water was encountered at a depth of approximately 22 feet btoc, indicating an increase of approximately 0 5 feet since the March 2005 sampling event • The ground water flow direction was inferred to be toward the southeast, at a gradient of approximately 0 003 ft/ft on-site The historical ground flow direction has been north and typically east,with this quarter's event representing a 45 degree change to the south from the typical flow direction • The detections of TPH-g compounds in the ground water sample collected from deep vapor well VW-2d demonstrate a contamination trend decrease to the lowest concentration detected (Appendix D) Detections of TPH-g in the deepest well(MW-6)confirms the vertical extent of the dissolved hydrocarbons, however, concentrations have been demonstrated as stable over the monitoring events Decreased TPH-g and BTEX concentrations during the remediation period may suggest decreased sources for the desorption of hydrocarbons from soil into ground water and the Iikely destruction of hydrocarbon mass by the ozone contact oxidation • Fuel additives were not detected in the samples collected • 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 Since operation of the ozone air sparge system commenced, dissolved oxygen concentrations in samples collected from wells at the IAdvanced GeoEnrnronmental,Inc