Ten-year radiocesium fluvial discharge patterns from watersheds contaminated by the Fukushima nuclear power plant accident

• DOI: 10.1016/j.jenvrad.2021.106759
• Publication Date: 2021-10-25T13:45:36Z
• Authors: Shinji Ueda; Hidenao Hasegawa; Yoshihito Ohtsuka; Shinya Ochiai; Takashi Tani
• Keywords: Deposition; Fukushima Nuclear Accident

After the Fukushima Dai-ichi nuclear power plant accident in March 2011, fluvial discharge of 137Cs from watersheds to rivers was analyzed between 2011 and 2021. The concentrations dissolved particulate were measured river water samples collected two (the Hiso Wariki rivers, mainly draining farmlands forests, respectively) approximately 4-7 km2 a montane area areal deposition 134+137Cs; 1-3 MBq·m-2 2011) Iitate Village, Fukushima. Over 10 yr analysis, decreased by 70 50 times, respectively, that form 150 130 respectively. Moreover, apparent Kd (distribution coefficient) for both have increased gradually over these periods. In rates through 0.63% 0.46% per year total amount deposited their catchments, respectively; however, 2021, had 0.09% 0.03% year. cumulative farmland- forest-dominated 1.95% 1.33%, These farmland-dominated ∼1.4-fold greater than those river. ∼90% occurred while remaining ∼10% form. Thus, within due discharged 10-yr period; majority remains stored soils litters etc. catchment area. results indicate outflow land-to-ocean will be limited future, as export is expected continue decreasing.