A radiochemical procedure for the determination and speciation of radiocobalt in environmental waters

Abstract Radiocobalt can occur in the aquatic environment in two different oxidation states. Under both fresh and saline conditions uncomplexed Co(II) normally predominates, however in certain circumstances anthropogenic Co(III) picolinate, and to a lesser extent, naturally occurring cyanocobalamine may also be present. Some complexed species are sufficiently stable to persist in the environment for considerable periods of time and thus influence the behaviour and distribution of radiocobalt. An analytical procedure has therefore been developed to permit the chemical separation and determination of the concentrations of Co(II) and Co(III) radionuclide species in environmental waters. Details of the scheme are presented along with a discussion of the relative stabilities of the more important cobalt complexes. Decontamination from interfering radionuclides and the radiometric assay of three environmentally important cobalt radionuclides are also considered.