Japan Geoscience Union Meeting 2014

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

[M-AG38_2AM1] Dynamics of radionuclides emitted from Fukuchima Dai-ichi Nuclear Power Plant in the environment

Fri. May 2, 2014 9:00 AM - 10:45 AM 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:Kazuyuki Kita(Faculty of Science, Ibaraki University)

9:45 AM - 10:00 AM

[MAG38-04] Study on the carrier of airborne radiocesium collected for six month in Tsukuba after the Fukushima nuclear accident

*Naoki KANEYASU1, Toshihiro KOGURE2, Hiroki MUKAI2, Hideo OHASHI3, Fumie SUZUKI3, Naofumi AKATA4, Tomoaki OKUDA5, Fumikazu IKEMORI6 (1.National Institute of Advanced Industiral Science and Technology, 2.Graduate School of Science, The University of Tokyo, 3.Tokyo University of Marine Science and Technology, 4.National Institute for Fusion Science, 5.Faculty of Science and Technology, Keio University, 6.Nagoya City Institute for Environmental Sciences)

Keywords:radiocesium, size distribution, re-suspension, electron microscope, autoradiograph

To obtain the knowledge on the physico-chemical properties of airborne radionuclides, we had been collected size-resolved aerosol in Tsukuba, Japan, since April 28, 2011, although the data obtained do not include the first radioactive plumes that reached to Tsukuba on March 15, 2011. From the initial result, we proposed a hypothesis that the sulfate aerosol was the potential carrier of the 134Cs and 137Cs that had undergone the middle- to long-range transport from the damaged reactor. We further inferred that re-suspended soil particles that attached radionuclides were not the major airborne radioactive substances from late April to May, 2011 (Kaneyasu et al., 2012). Nevertheless, there are some issues to be addressed on the nature of airborne radionuclides. Those are, a) until when the sulfate aerosol acted as a carrier of the radiocesium released from the reactor, or the other substances acted as carriers instead, and b) what is the carrier substance when the re-suspension or re-emission of became the dominant source in the airborne radiocesium.In this study, we address these subjects by analyzing the long-term aerosol samples collected later than those presented in the previous study. The temporal change in the activity size distribution of radiocesium for six month will be discussed. In addition, the carrier substance of radiocesium in the coarse mode size range aerosol is investigated by use of the autoradiograph and scanning electron microscope to the aerosol sample collected in 2011 summer.