deer and antelope are protected against hunting. These are attractive possibilities under present drives for preservation of native species. Surface waters in the area of interest to this proposal all empty into closed basins as has been pointed out previously, and these receiving points for runoff generally are close; a few to tens of kms. In addition, that is, within the rates of movement of soil particles and Pu particles, possibly because of the greater density of the latter, will undoubtedly be different. It seems reasonable that Pu will likely move much slower than clay fractions, and possibly less rapidly than the silt fractions. into the dry lakes (the playas), Movements if this occurs, leave some unaswered questions, but the movement will undoubtedly be very slow and dilutions of the Pu contaminant will likely bring it nearer to worldwide fallout concentrations. However, the character- stics of rainfall in this region of NTS, which often occurs as intense, local, and short-lived storms, provide some further uncertainties. There appear to be natural forces at work which will further reduce Pu movement. Pu, on the soil surfaces, will undoubtedly continue to reach greater depths in the soils with weathering, primarily wetting and freeze-thawing. et al. As pointed out by Essington (1975), this will continue to reduce the quantities of material available for wind distribution and, in fact, may be the primary factor in the reduction of airborne material noted by Phelps and Anspaugh (1975), previously mentioned. Within the soils, if Pu is in the oxide or hydroxide, as suggested by Tamura then there is a possibility of chemical inacti- (1975), vation over intermediate time periods as suggested by Wallace and Romney (1975), a process which may further reduce the amounts of Pu for wind dispersion and plant and animal uptake. 176