Department of International Environmental and Agricultural Science, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu 183-0059, Japan.
Environ Sci Process Impacts. 2015 Jun;17(6):1157-63. doi: 10.1039/c5em00063g. Epub 2015 May 15.
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.
在这项研究中，我们使用降雨模拟器研究了降雨对福岛县农田径流量、土壤侵蚀以及放射性铯排放的影响。模拟强降雨（50mm/h）会产生大量的径流量和土壤侵蚀。径流水沉积物中放射性铯（(134)Cs 和 (137)Cs 的总和）的平均浓度约为 3500 Bqkg(-1)干土，是田间土壤中测量浓度的两倍多，这在使用 (137)Cs 损失来估算长期土壤侵蚀的研究中应予以考虑。然而，通过一次径流水排放的铯估计质量不到田间铯库存的 2%。这表明，通过土壤侵蚀排放的铯不是减少福岛县污染土壤放射性的重要因素。然而，携带放射性铯的侵蚀泥沙将沉积到河流系统中，并可能对水生生物构成放射性风险。
