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ORC will stop releasing when dry and begin to release again when rehydrated; however, it is stable at 2-3% moisture, which facilitates storage and handling. The release rate of oxygen, in systems evaluated thus far, starts out as pseudo-first order as in: - d[Mg02]/dt = d(%02)Idt = k M9 0 I ( 2] The amount of oxygen released is therefore given by: 102JA021ta = 1-IM9021AM90211 = 1-e' where the subscript "t" refers to the amount of oxygen produced by time t which equates f to the fraction of M902 reacted. After several hours to several days, the release kinetics change to a pseudo-zeroth order expression where the release is simply a linear function R of time. E The by-products of the reaction as presented in the equation are oxygen and a magnesium hydroxide slung which is essentially Milk of Magnesia. The oxygen is consumed and the insoluble magnesium hydroxide remains. When formulated as ORC-concrete, the spent material can be easily removed before recharging with fresh ORC. The issue of whether or not any significant chemical oxidation occurs with ORC merits review. Although there is a widely held belief that magnesium peroxide first degrades to hydrogen peroxide, which then releases oxygen upon decomposition, a detailed examination of the thermodynamics involved shows this is false; the full technical detail is submitted as Exhibit 3. Essentially, the driving force for the release of oxygen is the reaction which forms magnesium hydroxide which releases the oxygen directly. Therefore, ORC is a source of slowly released molecular oxygen which finds its way into biological oxidation processes and does not have a significant ability to chemically oxidize compounds or remediating organisms by powerful free-radical mechanisms as is the case with hydrogen peroxide and peroxide hydrates. 3. Proof of Effic icy Product/Method The first field evaluations of oxygen barriers were made by the University of Waterloo and the results entered the peer-reviewed literature (Bianchi-Mosquera et al. 1994. Enhanced degradation of dissolved benzene and toluene using a solid oxygen releasing compound. GWMR, Winter, pp.120-128). This is provided as Exhibit 4. The study clearly demonstrated the effectiveness of ORC, particularly with respect to the fact that the results in all cases were achieved with sub-optimal applications of product. In future applications, the amount of ORC in the barrier could be increased considerably and/or be made with a higher percentage of active oxygen. Regenesis clearly recognizes it is in a engineering phase, that has just followed a period in which the validity of the basic • concept has been proven. Oxygen can be delivered to the subsurface in a passive, low cost time release manner, which can be effective in the remediation of modest levels of