Étude comparée de la fixation et de la désorption du zinc 65 par un mollusque marin (Mytilus galloprovincialis LmK) et un mollusque dulcicole (Unio requieni Michaud)

Abstract

The kinetics of zinc 65 contamination and distribution was studied in two species of mollusks: a salt water (Mytillus galloprovincialis LmK) and a fresh water (Unio requieni Michaud) species. After 50 days the concentration factor was approximately 500 for Unio requieni, but only 30 for Mytilus galloprovincialis on the 31st day of contamination. Radionuclide retention was essentially localized in the internal organs: 82.5 p. cent for Unio requieni, and 68.1 p. cent for Mytilus galloprovincialis. Zinc 65 desorption was also examined. It was a much slower and gradual process than contamination. Two biological half-lives for zinc 65 were determined for each species. The shorter half-life was similar in both cases (5 days), while the second was somewhat longer for Mytilus galloprovincialis (130 days) than for Unio requieni (80 days). The distribution of zinc 65 remaining in the organism was slightly different from that observed at the end of the contamination period. With respect to the total activity in the animal the radionuclide concentration in the internal organs was higher: 96 p. cent for Unio requieni and 72.6 p. cent for Mytilus galloprovincialis. RADIOPROTECTION

Metabolism of zinc in the mussel, Mytilus edulis (L.): a combined ultrastructural and biochemical study

“…This model can also explain the different excretion rates for zinc in Mytilus reported by previous workers. Thus in whole animals, components with half-lives of < 1 day, 3-4 days and 48-60 days were reported by Van Weers (1973); 5 and 130 days (Foulquier & Baudhuin, 1976); 76 days (Young & Folsom, 1967) and 130 days (Seymour & Nelson, 1973). Both Van Weers (1973) and Keckes et al (1968) found that the relative contribution of these components varied with the length of the uptake periods, the short-lived components only making a significant contribution to the percentage excreted after brief exposure periods (less than 2 weeks).…”

“…Its radioisotope, the neutron-induced radionuclide 65 Zn, is also released into the sea in significant quantities. Many radiological studies have therefore been carried out both on the uptake of 65 Zn by Mytilus (Boroughs, Chipman & Rice, 1957;Brooks & Rumsby, 1965;Chipman, Rice & Price, 1958;Kameda, Shimizu & Hiyama, 1968;Keckes, Ozretic & Krajnovic, 1969;Pentreath, 1973;Van Weers, 1973) and its loss from contaminated animals (Foulquier & Baudhuin, 1976;Keckes, Ozretic & Krajnovic, 1968;Seymour & Nelson, 1973'•> Van Weers, 1973Young & Folsom, 1967). Other studies have been oriented towards the use of Mytilus as an indicator organism by comparison of water and animal zinc concentrations at different collection sites (e.g.…”