Behavior of radioactive caesium in the environment; Understanding based on observation and analysis

Iijima, Kazuki  

Behavior of radioactive cesium in the environment from the forest to the estuary was discussed by comparing the data obtained from observations and laboratory experiments with the analytical results for the eight river systems in coastal area of Fukushima Prefecture. Concentration of dissolved radioactive cesium in river water decreased with time, with seasonal variations that became higher in summer and lower in winter. The behavior was analyzed with a simulation tool based on the water circulation simulator GETFLOWS. The behavior of particulate radioactive cesium was well reproduced. On the other hand, in case of dissolved fraction, although the concentration level could be roughly reproduced, the seasonal variation and the temporary concentration increase at the beginning of heavy rain could not be reproduced. In the current simulation, only the desorption is considered as the dissolving process, so that the contribution of other processes was considered.