isolation, nonmanipulation, and protective nondisturbance may be an adequate treatment of Pu-contaminated areas. treatment will, however, This hypothetical be restricted to those contaminated areas of NTS which are within closed drainage basins as, for example, both Yucca and Frenchman basins. Some arguments may be applicable, however, to other nearby areas with similar adaphic and environmental conditions. The position of this paper is that the present hazards of Pu in the NTS environment are minor and are diminishing, that protecting these areas from further disturbance will accelerate the rate of diminishing hazards. in the long term, That is, the bioenvironmental processes will, contribute to the continued decrease in the availability of Pu to the biotic cycles. In the very long term, a combination of environmental, geochemical, and geological processes will reduce the hazard in insignificance. Wallace and Romney (1975) have reviewed the literature and decontam- ination procedures as a basis for a report on the feasibility of decontamination of Pu-contaminated areas in Nevada. They have also suggested the alternative that the areas not be further disturbed, and have provided support for that alternative. In order to avoid duplication of their material, this paper attempts to provide further support not given by Wallace and Romney and to provide further discussion of some points not detailed in their report. The Wallace and Romney report should therefore be used as a supplement to information provided herein. BIOENVIRONMENTAL PARAMETERS AFFECTING PU AVAILABILITY TO FOOD CHAINS Movement of Pu within ecosystems is determined by many factors. Because of the distribution of Pu on or near the soil surfaces at NTS, and because it is thought to be in the metallic or oxide state, its movement is determined by wind and weather within the 168