Distribution of 137Cs and 90Sr in various tissues and organs of freshwater fish in Finnish lakes

The degree of radiocontamination in fish is usually analysed to estimate doses to fish consumers, for which the radionuclide contents in the edible parts of fish are needed. Recently increasing attention has been focused on radiation protection in plants and animals. To estimate the effects of radiation on fish, the distribution of radionuclides in various organs and radiosensitivity of the organs must be known. A step towards this was taken when the Radiation and Nuclear Safety Authority (STUK) of Finland determined the distribution of 137Cs and 90Sr in muscle tissue, skin + fins, and bones in perch samples, in muscle and bones or in muscle, skin + fins, and bones in pike samples and in muscle + skin + fins and bones in vendace samples. Accumulation of 137Cs in fish liver, spawn and sperm was also studied and compared with respective values in the edible parts. The importance of skin and fins was evident as a source of 90Sr to fish. Fish sperm showed somewhat higher activity concentrations of 137Cs than muscle.