UPTAKE FROM WATER, DEPURATION AND TISSUE DISTRIBUTION OF AG-110M IN A FRESH-WATER FISH, CYPRINUS-CARPIO L

Radionuclide accumulation was studied on a group of 20 fish maintained at 20 +/- 1 degrees C in spring water containing 30 Bq mL(-1) of Ag-110m. Because of a very significant radionuclide adsorption onto available surfaces and in order to simulate chronic exposure, the water was completely renewed three times a week. Accumulation of Ag-110m was slow, with an estimated time to maximum contamination level of 180 days. The concentration factor, calculated from the ratio of the integrals of the curves representing the radionuclide concentration in filtered water and in whore fish reached a maximum value of 106 (w.w.). After 41 days exposure, 10 fish were placed in non-labelled water, renewed daily, to follow Ag-110m depuration. A two-compartment exponential model was fitted to the depuration data. The corresponding radionuclide half-lives were relatively short, 0.8 (Tb-1) and 30 days (Tb-2), and after 6 weeks the fish retained about 30% of their initial Ag-110m content. The liver and digestive tract retained most Ag-110m Although they only represented respectively about 4 and 10% of the total body mass, these two organs accounted for 30-40% of the total radionuclide body burden.