Radiocesium sorption in relation to clay mineralogy of paddy soils in Fukushima, Japan

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• 作者：Atsushi Nakao ; Sho Ogasawara ; Oki Sano ; Toyoaki Ito ; Junta Yanai
• 关键词：Cs-fixation capacity ; Micaceous minerals ; Radiocesium Interception Potential (RIP) ; Native K content ; XRD
• 刊名：Science of the Total Environment
• 出版年：15 January, 2014
• 年：2014
• 卷：468-469
• 期：Complete
• 页码：523-529
• 全文大小：712 K

文摘

Relationships between Radiocesium Interception Potential (RIP) and mineralogical characteristics of the clay fraction isolated from 97 paddy soils (Hama-dori, n = 25; Naka-dori, n = 36; Aizu, n = 36) in Fukushima Prefecture, Japan were investigated to clarify the mineralogical factors controlling the ¹³⁷Cs retention ability of soils (half-life 30.1 y). Of all the fission products released by the Fukushima accident, ¹³⁷Cs is the most important long-term contributor to the environmental contamination. The RIP, a quantitative index of the ¹³⁷Cs retention ability, was determined for the soil clays. The composition of clay minerals in the soil clays was estimated from peak areas obtained using X-ray diffraction (XRD) analyses. The predominant clay mineral was smectite in soils from Hama-dori and Aizu, while this was variable for those from Naka-dori. Native K content of the soil clays was found to be an indicator of the amount of micaceous minerals. The average RIP for the 97 soil clays was 7.8 mol kg^鈭?#xA0;1, and ranged from 2.4 mol kg^鈭?#xA0;1 to 19.4 mol kg^鈭?#xA0;1. The RIP was significantly and positively correlated with native K content for each of the geographical regions, Hama-dori (r = 0.76, p < 0.001), Naka-dori (r = 0.43, p < 0.05), and Aizu (r = 0.76, P < 0.001), while it was not related to the relative abundance of smectite. The linear relationship between RIP and native K content not only indicate a large contribution of micaceous minerals to the ¹³⁷Cs retention ability of the soil clays, but also could be used to predict the ¹³⁷Cs retention ability of soil clays for other paddy fields in Fukushima and other areas.