Biokinetic and bioaccumulation studies in rats after a chronic exposure to uranium by contaminated water ingestion. Preliminary results.
Workshop on Internal Dosimetry of Radionuclides - Occupational, Public and Medical Exposure - 9-12 September 2002 - New College, Oxford, United Kingdom
M. DONNADIEU-CLARAZ, V. CHAZEL, P. HOUPERT, F. PAQUET
Chronic exposure to radionuclides at low level may induce biological responses that are different from those observed after acute exposure at high dose because of the processes of bioaccumulation in target organs. A bioaccumulation of radionuclides may have an impact on the biokinetics of incorporated compounds and on the radiation doses delivered to organs. In the same time, the phenomena of bioaccumulation, if evidenced, could lead to biological disturbances of organism mainly on the functioning of central nervous, reproductive and immune systems.
The aim of this work that form part of ENVIRHOM research programme for the radioprotection from environment to man, is to study the consequences in term of biokinetics and bioaccumulation induced by a low level chronic ingestion of uranium in rats. Research focused at first on maximal radionuclide doses encountered in environmental situations and determined on the basis of concentrations found in particular situations. The preliminary results obtained from rats exposed to a chronic intake of uranium contaminated water (40 mg/l) are detailed. The measurement of absorption rates and kinetics were done by radiometric measurements of excreta and retention organs. The influence of the chronicity of exposure on the excretion kinetics of coumpounds are discussed. The microlocalisation studies were performed by using transmission electron microscopy coupled with an X-ray electron dispersion analysis. These studies allowed to determine for the target organs, whether the uranium is homogeneously distributed in the tissues and cells or whether, on the contrary, it is localised in particular structures.