239,240Pu and 137Cs concentrations in some marine biota, mostly from the seas around Japan

Recent 239,240Pu and 137Cs concentrations in some marine biota collected mostly from the seas around Japan were determined. Ash samples were digested with hot nitric acid, and the radionuclides were purified by ion exchange processes, then their alpha and beta radioactivities were measured. 239,240Pu concentrations were in levels of 1/10 to 1/100 of 137Cs concentrations, and showed values of some pCi/100 kg-raw in muscles. No clear difference was observed in the contents of the radionuclides of muscles between shallow waters and deep bottom inhabitants. Considerable variation in 239,240Pu concentrations were shown among organs and tissues, but 137Cs showed no such discrepancy. Apparent high concentration factors (CF) for 137Cs of the deep water inhabitants were supposed to be caused by the contribution of the food chain in the deep sea. Concentrations of the radionuclides in krill and fur seal were also discussed. (author)