ABSTRACT
The purpose of below-ground nuclear waste disposal is to protect the safety and health of the public by limiting or preventing radioactive wastes from reaching the accessible environment. The interactions between an indigenous microbial population and radioactive wastes are more subtle in the far-field. The attached microbial population would occupy a percentage of the total matrix surface area with both cells and exopolymers. The energy required for minimal microbial metabolism in the vadose zone can be derived from a variety of sources, such as endogenous metabolism, metabolism of exogenous organic material, or metabolism of diffused, gaseous substrates. Many microorganisms in a subsurface vadose zone environment may be attached to the matrix. The degree of relative metabolic activity in the vadose zone determines the amount of small molecular weight complexing agents. Complexed/chelated radionuclides may therefore be transported to a new region of the vadose zone, and would become subject to microbial degradation.
