Initial uptake, distribution and loss of soluble¹⁰⁶Ru in marine and freshwater organisms in laboratory conditions

The early uptake, distribution and loss by some freshwater and marine organisms of¹⁰⁶Ru in solution in the water and originating from nitrosyl nitrate complexes, were studied during short periods (1-10 days) in laboratory conditions. Freshwater animals used were: Anodontaanatina (mussel), Lymnaeastagnalisand Viviparuscontectus (snails), and Albumus lucidus (the bleak: A fish); marine organisms were: Fucus vesiculosus (an alga), Mytilus edulis (the mussel), Littorina littorea and Purpura lapillus (two gastropods). The initial uptake and distribution of 108Ru is similar when one compares the marine and the freshwater lamellibranch {Mytilus and Anodonta); but the fixation of Ru is much higher in the freshwater snail Viviparus than in the fish Albumus. Surface adsorption is likely to play an important role in the radiocontamination of the organisms by soluble Ru. This is suggested by the high Ru content of thin structures in direct contact with water such as the byssus, the border of the shell and the operculum. The temperature-dependance (Q,₁₀≈1.8) of the initial uptake of Ru in the marine organisms suggests some metabolic interference, although it is striking that, both in the alga and in the animals studied, this temperature-dependance as well as the general kinetics of the uptake (sequence of two exponentials) are similar.