90Sr Activity in the High Seas and Coastal Regions of Korea-Japan-Russia-China Compared with Exponential Decay of 90Sr Global Fallout

Concentration and activity of 90Sr in the high seas and coastal regions of Korea-Japan-Russia- China from the global fallout to 2000 were studied. The variation of 90Sr in these study areas decreased continuously from 1964 when global fallout radioactive was started to 2000. Suggesting that from 1964 to present the 90Sr activity from any local resources at Korea-Japan-Russia-China doesn’t significant, because the 90Sr activities much lower compared with the exponential decay, it caused by effective environmental half-lives. In conclusion, the activity of 90Sr in the high seas and coastal regions of Korea-Japan-Russia-China originated entirely from the global fallout rather than from any local point sources.