Accumulation and Retention of Ingested Ruthenium-106 by Genuine Goby

Although there are a number of reports concerning the uptake of various radioactive nuclides from surrounding water by aquatic organisms1), the quantitative informations on the transfer of radioactive substances through aquatic food chains have been scarcely obtained until now. In near future, in accordance with the rapid developement of the peaceful utilization of atomic energy in Japan, the problem of radioactive contamination of marine organisms may arise from the radioactive waste disposal into the sea. Radioactive ruthenium is known to be one of the most abundant radio-isotopes to be released from the nuclear fuel reprocessing plant. In recent extensive studies by MAUCHLINE et al.2,3,4) and LONGLEY et al.5) based on the results of survey on the biological distribution of the radioactivity in the Irish sea due to the discharge of the radioactive effluent from Windscale Works, it is reported that 106Ru is frequently the major radioactive contaminant found in seaweeds, marine invertebrates and marine fishes. Radioactive ruthenium in these marine organisms should originate from both contaminated sea water and food. The present paper deals with the accumulation and retention of ingested 106Ru by coastal sea fish when fed on the contaminated food, and the transfer of this radionuclide through a food chain in coastal sea environment is discussed in order to give some information on the possible role of food chain transfer of the nuclide in radioactive contamination of marine organisms.