Concentrations of90Sr and137Cs/90Sr activity ratios in marine fishes after the Fukushima Dai-ichi Nuclear Power Plant accident

Strontium-90 (90Sr) was released together with radioactive cesium (Cs) from the Fukushima Dai-ichi Nuclear Power Plant (FNPP) accident. Although the total amount of 90Sr released into the marine environment from the FNPP was estimated to be a factor of 100 lower than that of 137Cs, the public have been concerned about the safety of commercial species because of the tendency of accumulation in bones of organisms, its long physical half-life and less information about 90Sr concentrations in commercial species. In this study, we investigated the concentrations of 90Sr in marine fishes off Japan before and after the FNPP accident. Except for within a 20-km radius from the FNPP, 90Sr concentrations higher than the background level (