Transuranium and other alpha-emitting nuclides in the marine environment

Marine environment contains naturally occurring alpha-emitting transuranium nuclides which are discharged from nuclear fuel reprocessing plants into the marine environment. Calculation of their potential of both the inhalation pathway and ingestion pathway to man, their residence time in the oceans, their loss to sediments, the chemical state in which they exist in sea water, their oxidation states in sea water, and their biological availability to sea organisms are discussed. The areas where data are lacking are indicated. Studies on the Windscale Site (U.K.) are extensively referred to in the discussion of above-mentioned aspects. It is brought out that the study of the naturally occurring actinides can be useful in the understanding of behaviour of man-made radionuclides in the marine environment, because many of the former are good analogues of the latter. (M.G.B.)