Behavior of dissolved radiocesium in river water in a forested watershed in Fukushima Prefecture

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• 作者：H. Tsuji ; T. Nishikiori ; T. Yasutaka ; M. Watanabe ; S. Ito ; S. Hayashi
• 刊名：Journal of Geophysical Research: Biogeosciences
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：121
• 期：10
• 页码：2588-2599
• 全文大小：835.5KB
• ISSN：2169-8961

文摘

Dissolved radiocesium concentrations in river water in a high-dose-rate forest watershed in Fukushima Prefecture were investigated under base flow and storm flow conditions. Under base flow conditions, dissolved ¹³⁷Cs concentrations in water (Bq/L) were relatively high in summer, and these levels were higher than particulate ¹³⁷Cs concentrations (Bq/L). Under storm flow, particulate ¹³⁷Cs concentration became dominant as the suspended solid concentration increased. Throughout the monitoring period, dissolved ¹³⁷Cs concentrations in water (Bq/L) were higher under storm flow than base flow conditions and were positively correlated with runoff intensity. Factors influencing changes in dissolved ¹³⁷Cs concentrations were investigated by measuring the ¹³⁷Cs concentration of suspended solid (Bq/kg) and dissolved ¹³⁷Cs of unsaturated soil water, throughfall, and rainfall, together with other main solute concentrations. The ¹³⁷Cs concentration per unit weight of suspended solids in river water was not strongly correlated with runoff intensity. Additionally, dissolved ¹³⁷Cs concentrations of soil water, groundwater, and rainfall were not detected, while higher dissolved ¹³⁷Cs concentrations were detected in throughfall than river water. K⁺ concentrations were higher under storm flow than base flow, and dissolved organic carbon increased toward the peak flow rate. These findings suggested that one main factor influencing generation of dissolved ¹³⁷Cs in the river water was leaching from organic material in flooded areas. However, further investigation is needed to clarify the dominant source of dissolved ¹³⁷Cs in river water.