Chemical speciation and bioavailability of uranium in freshwaters: Illustration for a bivalve biological model used as contamination radioindicator.

F. Denison, J. Garnier-Laplace, C. Adam and J.T. Smith Actes du congrès ECORAD, 3-7 sept 2001, Aix en Provence, France Radioprotection - Colloques, volume 37, C1-599/ C1-604.

The transfer of contaminants from the environment to the biota depends on the abundance and availability of the contaminant in its various physico-chemical forms. To assess the bioavailability of uranium in the environment it is necessary to characterise the relative contributions of its physico-chemical fractions. A reductionistic approach has been employed to precise the system specific factors that regulate the uptake of uranium from the dissolved fraction by the freshwater bivalve species Corbicula fluminea in well defined conditions. Results from preliminary experiments are presented which demonstrate that it is possible to apply this methodology to investigate which uranium solution species are able to be transferred to the biota.