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19 November 2009 AGE-NC Project No. 02-0950 Page 10 of 13 wells MW-1 and MW-3 through MW-6;these wells are considered non detect wells for constituents of concern. Additionally, following the July 2007 corrective action measures at the site, dissolved TPH-d and BTEX concentrations decreased at wells MW-2 and MW-7 to non detectable levels, while TPH-g concentrations declined to 520 µg/1 and 300 gg/1, respectively. Based on plots of TPH-g, TPH-d and benzene versus time (Appendix E), a definitive trend of decreasing dissolved concentrations has been evident at the site from monitoring wells MW-2 and MW-7. At various times between September 2007 and May 2009, all dissolved TPH-d and BTEX concentrations declined to non detect levels. Additionally, based on the plots of TPH-g concentrations versus time, a trend line was utilized to project that TPH-9 concentrations should reach non detect levels at well MW-2 by October 2010, and should reach non detect levels at well MW-7 by August 2010. The estimated maximum extent of dissolved petroleum hydrocarbons is depicted in Figure 12, and is representative of ground water conditions prior to corrective action. From the well of greatest impact(i.e.MW-2),the dissolved plume extends 50 feet toward the north-northwest,52 feet toward the south-southeast, 19 feet toward the west and 33 feet toward the east. Based on the data, the dissolved extent can be separated into three contour zones of 10,000 gg/1, 1,000 gg/l and 50 gg/1(i.e non detect). The volume of each contour zones can be determined by utilizing the formula for an elliptical cylinder.Based on the estimated volumes of the above three contoured zone,the apparent maximum volume of TPH impacted ground water at the site yielded approximately 11.41 pounds of TPH(equivalent to 1.83 gallons).Maximum dissolved mass-volume calculations are included in Appendix J. The estimated remaining extent of dissolved petroleum hydrocarbons is depicted in Figure 13, and is representative of the most recent ground water monitoring conditions (i.e. May 2009). From the well of greatest impact(i.e.MW-2),the dissolved plume extends 30 feet toward the north-northeast, 10 feet toward the south-southwest,nine feet toward the west and 7 feet toward the east. Based on the low concentrations (i.e. 300 gg/1 and 520 gg/1) detected at wells MW-2 and MW-7, the distribution of dissolved TPH concentrations at the site can be estimated utilizing an elliptical cylinder and an average concentration of 410 gg/1. Based on the above assumptions at the site, the apparent remaining volume of TPH impacted ground water yielded approximately 0.09 pounds of TPH(equivalent to 0.014 gallons).Remaining dissolved mass-volume calculations are included in Appendix J. 7.0. DISCUSSION AND CONCLUSIONS Based on data collected during site assessment and ground water monitoring events at the Masonite site, AGE concludes: Advanced GeoEnvironmental,Inc.