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Movement of toxic and radioactive substances in aquifer systems occurs in all three phases and is controlled by both hydrologic and chemical forces. Solute movement can be greatly affected not only by physical dispersion, but by other factors such as exchange sorption, chemical kinetics, and ionic distributions. Movement of gases and particulate material in the unsaturated zone are controlled by many additional factors. Knowledge of how these physical and geochemical factors affect prediction of movement of toxic and radioactive wastes is only generally known for ideal systems. This project's objective is to develop field methods and techniques that will yield values for physical and geochemical factors of regional...
Stable and radioactive isotopes such as oxygen, hydrogen, carbon, nitrogen and sulfur have proved to be extremely useful tracers of hydrologic pathways, biogeochemical processes, and residence times of waters and solutes. However, use of these isotopes as tracers is presently hampered by our limited understanding of the physical processes and chemical reactions influencing isotopic compositions. The unsaturated zone, particularly the soil zone and the top of the water table, is probably the portion of the hydrologic system most responsible for alteration of the isotopic compositions of potential isotope tracers, this environmental component is also one of the least studied. The overall goal of this project is to...
Categories: Project; Tags: Isotopic Tracers, Radioisotopes
Uranium mill tailings and related forms of low-level radioactive waste contain elevated contents of naturally occurring radionuclides that have been brought to the surface, processed for the recovery of uranium and/or other components and then disposed of in near-surface impoundments. The long-term fate of the tailings and their constituents will be determined by surficial earth processes. Project objectives are to study the chemical form in which radionuclides and selected stable elements are retained in surficial earth materials, particularly uranium mill tailings, and to identify processes operating in natural aqueous and terrestrial systems that may influence the transport of these constituents from these earth...