Microlocalization of artificial radionuclides in radiological protection of the environment

Though environmental biological equilibrium seems to be safeguarded as long as the radiological protection of man is assumed, a number of problems raised by environmental protection are not fully solved. In particular, there occur both macroscopic processes of concentration at some levels of the biological chains, and microlocalization at the cellular, subcellular and molecular levels. The long-term consequences of the non-uniform distribution of the radionuclides should therefore be assessed even if the contamination levels of the physical environment are very low. These aspects are of particular significance with alpha-emitters (plutonium and transplutonium elements), beta-emitters (chiefly tritium) and activation products, some of which are radioisotopes of biologically significant elements. The incidence of these processes is discussed in the light of recent and future developments in nuclear energy. This approach might open new avenues for investigations in environmental radiological protection. The concept of a concentration factor between the environment and the total organism must be supplemented by the concept of a localization and concentration factor at the subcellular level. The significance of the physico-chemical forms of the radionuclides and the parameters likely to modify the characteristics of membranes should be emphasized. Finally, an indication is given on priority measures in the area of investigations of the long-term consequences of low doses on environmental organisms.