title: Export of radioactive cesium from agricultural fields under simulated rainfall in Fukushima.
abstract: In this study, we investigated the impact of rainfall on runoff, soil erosion and consequently on the discharge of radioactive cesium in agricultural fields in Fukushima prefecture using a rainfall simulator. Simulated heavy rainfalls (50 mm h(-1)) generated significant runoff and soil erosion. The average concentration of radioactive cesium (the sum of (134)Cs and (137)Cs) in the runoff sediments was ∼3500 Bq kg(-1) dry soil, more than double the concentrations measured in the field soils which should be considered in studies using the (137)Cs loss to estimate long-term soil erosion. However, the estimated mass of cesium discharged through one runoff event was less than 2% of the cesium inventory in the field. This suggested that cesium discharge via soil erosion is not a significant factor in reducing the radioactivity of contaminated soils in Fukushima prefecture. However, the eroded sediment carrying radioactive cesium will deposit into the river systems and potentially pose a radioactivity risk for aquatic living organisms.
authors.affiliation: Department of International Environmental and Agricultural Science, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu 183-0059, Japan. pochi@cc.tuat.ac.jp.
authors.forename: Phong K
authors.initials: PK
authors.lastname: Thai
authors.forename: Yuma
authors.initials: Y
authors.lastname: Suka
authors.forename: Masaru
authors.initials: M
authors.lastname: Sakai
authors.forename: Kazuki
authors.initials: K
authors.lastname: Nanko
authors.forename: Jui-Hung
authors.initials: JH
authors.lastname: Yen
authors.forename: Hirozumi
authors.initials: H
authors.lastname: Watanabe
mesh_terms: D000383:Agriculture; D002588:Cesium Radioisotopes / Q000032:analysis*; D062406:Fukushima Nuclear Accident; D007564:Japan; D008956:Models, Chemical; D011834:Radiation Monitoring; D011847:Radioactive Fallout; D011891:Rain; D012990:Soil Pollutants, Radioactive / Q000032:analysis*; D014875:Water Pollutants, Radioactive / Q000032:analysis
chemical_list: D002588:Cesium Radioisotopes; D011847:Radioactive Fallout; D012990:Soil Pollutants, Radioactive; D014875:Water Pollutants, Radioactive