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27 October 2005 AGE-NC Project No. 96-0235 Page 4 of 11 TPH(g) hydrocarbons were diminished by >-90% in the soil by day 5 of ozonation. Individual hydrocarbon compounds decreased by 10-100x in both 8260 and 8020 soil analyses. TPH(g) hydrocarbons in the aquifer water phase increased— 30x after ozonation. This is probably simple mass transfer from the soil to water phase due to the oxidative loss of organic sorption sites in the soil. A decrease of 317 mg/kg TPH(g) occurred in the soil, with an increase of 2.7 mg/L in the aquifer water. Looking at the reaction vessel soil and water as though it comprised a section of the subsurface being ozonated, there was a 340/(33+3) or a 94% decrease in TPH(g) after 5 days, indicating that ozonation is an effective means of decomposing hydrocarbons. MTBE was `absent' from the Initial (and Final) soil presumably due to its high water solubility; MTBE decreased from 91 to <5 ppb in the aquifer water due to ozonation. The amount of hydrocarbon lost to purging by ozone was negligible compared to that oxidized by ozone,as evidenced by the"Ozone degassed front and back samples".As expected,simple purging alone, using a much higher gas to soil ratio in a U-shaped purge and trap sparge vessel, was completely effective. 1200 ppb acetone and 360 ppb MEK were observed in the Final water(but not Final soil) sample and small amounts of MEK were found in the front and back organic liquid traps downstream from the sample reaction vessel.The trace benzene found in the liquid traps may be an artifact of the tygon tubing used to connect them to the ozone destroying cartridges. Our lab has observed trace benzene arising from the degassing of tygon tubing in the past.Trace amounts of acetone and MEK were also found in the"N2 Sparged Sample".This discourages their description as ozonation by-products and their explanation remains unresolved. Acetone is ambient laboratory contaminant,but MEK is not. Acetone's diffusion through Teflon tubing, induced by flowing gas on the receiving side, with its partial breakdown to MEK is a possible explanation. Metals: Major AND Trace Elements Water The Initial water contained a fairly high sediment content, 1-3%,but the Final Water had negligible to low sediment,and the sediment content and precipitation reactions are believed to be responsible V for some difficulties in reconciling some metals data.This led to our reliance on"Total Recoverable" metals (TRM) values, for which data trends were clear. TRM determinations for the Initial and Final aquifer water were performed as follows. The Initial water including its suspended sediment was acidified with—2%HNO3 and remained in contact for a minimum of 16 hours.The aliquot of water withdrawn from the reaction vessel for the Final water was treated similarly. This is equivalent to "Total Recoverable Metals" as described by the EPA in method 200.8. This procedure was used because it was found that the amount of time that the water stood unpreserved prior to filtering and preserving dramatically affected the recovered �.. "dissolved" metals content. Advanced GeoEnvironmental,Inc.