ARCHIVED REPORTS_QUARTERLY MONITORING AND REMEDIATION REPORT - FIRST QUARTER 2007

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24 April 2007 AGE-NC Project No. 04-1207 Page 8 of 9 • During the January 2007 ground water monitoring event, ground water at the site was inferred to be flowing from a southeast-trending ground water ridge under a relatively uniform hydraulic gradient of approximately 0.004 ft/ft.This flow pattern is consistent with historically-observed flow directions at the site. • Petroleum hydrocarbons were detected only in monitoring well MW-1.TPH-g was detected at a concentration of 1,200 µg/1. BTEX compounds were detected at the following concentrations: 12 µg/l toluene, 23 µg/1 ethylbenzene, and 117 µg/1 total xylenes. • During the first quarter sampling event, petroleum hydrocarbons were detected only in monitoring well MW-1. TPH-g was detected at a concentration of 1,500 µg/1. BTEX compounds were detected at the following concentrations: 18 µg/1 toluene, 25 µg/1 ethylbenzene, and 127 µg/1 total xylenes. A graph illustrating trends in dissolved TPH-g concentrations in well MW-1 is included in Appendix I. • Ground water extraction activities were initiated on 26 January 2007 utilizing well MW-I as the extraction well.Groundwater is extracted from well MW-1 and routed through plastic tubing to an on-site 21,000-gallon, closed-top, steel Baker Tank. Power to the system is controlled by a timer, currently allowing the compressor to operate between 0615-hr and 2000-hr to minimize noise disturbance to nearby residences. Between 26 January and 28 March 2007, a total of approximately 19,000 gallons of ground water were extracted from well MW-1. • On 05 February 2007, one ground water sample from the ground water extraction effluent line was collected for analysis for petroleum hydrocarbon constituents.No constituents of concern were detected in the sample, which was collected after approximately ten days of ground water extraction. • The SVE system began operation at the site on 05 February 2007, and has been monitored and sampled weekly,thereafter.Between 05 February 2007 and 28 March 2007(the last SVE monitoring ofthe quarter),the SVE unit operated for approximately 580 hours;influent flow rates ranged from approximately 38 scfin to 90 scfin. TPH-g concentrations in soil-vapor samples have ranged from a starting high of 6,600 µg/1 to a low of 280 µg/1. A graph illustrating trends in TPH-g concentrations in extracted soil-vapor is included in Appendix I. • Approximately 255.4 lbs, or 40.9 gallons, of TPH-g were extracted from well VW-1 and processed between 05 February 2007 and 26 March 2007 (last soil-vapor sample collected in the first quarter). • On 17 November 2006,a ground water sample was collected from well MW-5 and analyzed for the petroleum hydrocarbon constituents listed in Section 2.3.;no constituents of concern were detected at or above laboratory detection limits. Advanced GeoEnvironmental,Inc.