Geologic Migration Potentials of Technetium-99 and Neptunium-237

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Science  30 Mar 1979:
Vol. 203, Issue 4387, pp. 1337-1340
DOI: 10.1126/science.203.4387.1337


Relatively mobile TcO+ and NpO2+ can be chemically reduced to less soluble oxidation states in the presence of igneous rocks, as predicted by oxidation-reduction measurements. Current risk assessments, which consider technetium and neptunium as potentially capable of migrating from high-level radioactive waste repositories, may be overestimating their potential hazard to the public since the Fe(II) content of many subsurface waters may maintain these elements in less soluble oxidation states.