Watershed‐Geochemical Model to Simulate Dissolved and Particulate ¹³⁷Cs Discharge From a Forested Catchment

Abstract

The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident occurred owing to the earthquake and tsunami on 11 March 2011, and caused environmental radioisotope pollution in terrestrial areas (Ministry of Education, Culture, Sports, Science and Technology, 2011). Cesium-137 ( 137 Cs) is a critical radioisotope remaining from the fallout owing to its high activity, long half-life (30.1 y), and potential impacts on humans and ecosystems.Approximately 70% of all land in Fukushima Prefecture is forest (Ministry of Agricultural, Forestry, and Fisheries, 2012), and 137 Cs is deposited predominantly in forest areas (Nakanishi et al., 2021). The affected forests have not been decontaminated (Ministry of the Environment, 2012). Around 65%-91% of the 137 Cs in the forests was