Japan Geoscience Union Meeting 2014

Presentation information

Print

Oral

Symbol M (Multidisciplinary and Interdisciplinary) » M-AG Applied Geosciences

[M-AG38_2AM2] Dynamics of radionuclides emitted from Fukuchima Dai-ichi Nuclear Power Plant in the environment

Fri. May 2, 2014 11:00 AM - 12:45 PM 501 (5F)

Convener:*Kazuyuki Kita(Faculty of Science, Ibaraki University), Yuichi Onda(Center for Research on Isotopes and Environmental Dynamics, University of Tsukuba), Teruyuki Nakajima(Atmosphere and Ocean Research Institute), Yasuhito Igarashi(Atmospheric Environment and Applied Meteorology Research Department, Meteorological Research Institute), Jun Matsumoto(Deaprtment of Geography, Tokyo Metropolitan University), Masatoshi Yamada(Institute of Radiation Emergency Medicine, Hirosaki University), Chisato Takenaka(Graduate School of Bioagricultural Sciences, Nagoya University), masayoshi yamamoto(Low Level Radioactivity Laboratory, Kanazawa University), jota kanda(Tokyo University of Marine Science and Technology), atsushi shinohara(Osaka university), Chair:Kimikazu Sasa(Faculty of Pure and Applied Sciences, University of Tsukuba)

12:30 PM - 12:45 PM

[MAG38-14] Desorption behavior of intrinsic cesium in smectite: Effect of aggregation on the cesium fixation in clay particles

*Keisuke FUKUSHI1, Haruka SAKAI2, Taeko ITONO3, Akihiro TAMURA3, Shoji ARAI3 (1.Institute of Nature and Environmental Technology, Kanazawa University, 2.College of Science and Engineering, Kanazawa University, 3.Graduate School of Natural Science and Technology, Kanazawa University)

Keywords:cesium, smectite, desorption, fixation, aggregation

The radiocesium from the Fukushima Daiichi nuclear power plant accident is retained at the surface soils around the power plant. The expandable fine grained clay minerals such as smectite and vermiculate are the candidates for the host phases of radiocesium. The sorption mechanism of cesium in the clay minerals is expected to be cation exchange reaction in the interlayer of the clay minerals. Therefore, the retained Cs must be desorbed to the solutions in the presence of high concentrations of major cations. On the other hand, some natural observations after the Fukushima accident have shown that the radiocesium in the contaminated soils or sediments is merely desorbed to the water even in saline solutions (e.g. Aoi et al 2013 JPGU meeting). The purpose of the study is to reproduce the unexpected fixation of cesium in clay minerals from the laboratory experiment by using standard well characterized smectite (Kunipia-F). The desorption behavior of intrinsic trace Cs (10 nmol/g from LA-ICP-MS) in smectite by major cations were systematically examined. The results of the present study showed that the aggregation of smectite by the presence of the divalent cations or high concentration of monovalent cations lead to the fixation of cesium in the clay aggregates.