Study on the environmental behavior of Chernobyl-derived radionuclides in Kyushu Island, Japan

The environmental behavior of Chernobyl-derived radionuclides in Kyushu Island was investigated for one month after the accident. The radioactivity level in airborne dusts was two orders of magnitude lower than that observed in Western Europe. The distribution of 131I in airborne dusts shifted to a larger particle size compared with other radionuclides. The radionuclide concentration in seaweeds varied depending on the geographical situation where the sampling was done. The biological half-lives in red algae were calculated to be 17.4 d and 32.9 d for 131I and 103Ru, respectively. The concentration factors in red algae were estimated to be 3 x 10(3) and 5 x 10(3) for 131I and 103Ru, respectively. The cooking effect of 131I in seaweeds and the committed effective dose equivalent through ingestion of seaweed were also evaluated.