Factors controlling the variability of 137 Cs concentrations in 5 coastal rivers around Fukushima Dai-ichi power plant.

The Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident led to the contamination by radiocesium (137Cs) of large drained areas. Cesium-137 concentrations in rivers result from complex transfer processes, depending on multiple forcings. Better knowledge of the factors controlling these concentrations is therefore a prerequisite to improve predictions of 137Cs transfers within river catchments. This study aimed at analyzing the spatial and temporal variability of 137Cs concentrations in rivers and identifying the key factors controlling their variability.