Influence du mode de contamination sur l'élimination du cobalt 60 par une phanérogame, un mollusque, un crustacé et un téléostéen dulçaquicole

Abstract

⁶⁰Co enters the environment with radioactive wastes from nuclear power reactors and fuel reprocessing plants as well as a component of fallout from nuclear tests.

A study of ⁶⁰Co in freshwater organisms has been carried out in order to compare the influence of different modes of uptake (immersion in contaminated water, ingestion of radioactive food, contamination by both food and water) upon the subsequent elimination.

The loss of ⁶⁰Co by Canadian pondweed Elodea canadensis is monophasic. For animal species, this phenomenon is biphasic, independently of the mode of uptake.

On the other hand, the biological half-life changes in relation to the vector of contamination. The same result is observed for the relative importance of the different compartments. This is easily explained because the mode of uptake determines the distribution of ⁶⁰Co in the organisms.

The turnover of ⁶⁰Co in the organisms is slow and the physical half-life of this radionuclide is relatively important (T_p = 5·27 years). Thus, the possible consequences of the release of this pollutant on freshwater life must not be neglected.