210Po behaviour in terrestrial environment: a review.
F. COPPIN*, S. ROUSSEL-DEBET (* post doc fellow at IRSN)
Radioprotection, vol.39, n°1 : 39-58
This bibliographical review illustrates the behaviour of 210 polonium in the terrestrial environment. Sources of 210Po in the atmosphere vary especially with the geographical localisation and the occurrence or the absence of mining activities. In soils, polonium, because of its atmospheric origin, is concentrated in the first upper centimetres. 210Po is rather immobile and adsorbed on minerai surfaces; it can (co)precipitate with metallic (oxi)hydroxides or in the form of sulphide. The main transfer pathway of 210Po to vegetation is foliar deposit, which is not, or only slightly, followed by incorporation or translocation. 210Po is transferred to animais mainly by ingestion, with relatively high transfer factors. In freshwaters, 210Po is generally immobile in the form of insoluble Po(IV) and/or associated with the particulate or colloidal phase. Plankton, invertebrates and fish concentrate the 210Po, especially in soft tissues. Polonium, which is an omnipresent natural radionuclide, is likely to occasion a significant exposure to man, compared with other natural or artificiel radioisotopes. Nearly ail studies derive from in situ measurements and are very descriptive, therefore experimental work aiming at a better knowledge and modeling of its behaviour in the terrestrial environment would be useful