[M-AG44] Dynamics of radionuclides emitted from Fukushima Dai-ichi Nuclear Power Plant in the environment

[MAG44-P03] Contribition of bioaerosols to the atmospheric resuspension of radioactive cesium in summer and autumn

*Kazuyuki Kita¹, Naho Hayashi¹, Koutaro Minami¹, Teruya Maki², Kentaro Hosaka³, Yasuhito Igarashi⁴ (1.Faculty of Science, Ibaraki University, 2.Kanazawa university, 3.National musium of nature and science, 4.Institute for Integrated Radiation and Nuclear Science, Kyoto University)

Keywords:radioactive cesium, atmospheric resuspension, bioaerosols

Radio-cesium emitted by the TEPCO FDNPP accident has been deposited on soil and vegetation after transpiration in the atmosphere. Re-suspension of the deposited radio cesium is increased atmospheric concentration of its radioactivity even now. Quantitative understanding of re-suspension processes of radio-cesium is essential for the modelling of radio-cesium transition from soil and vegetation via the atmosphere.
Our group showed the seasonal variation of atmospheric radio-cesium sampled in a polluted area in Fukushima (Kinase et al., 2018) and possibility that bioaerosols such as fungal spores bring radioactive cesium into the atmosphere especially in summer and autumn near forest area (Igarashi et al., 2019). In this study, quatitative estimation of contribution of bioaerosol to the atmospheric resuspenstion of atmospheric radio-cesium.
Atmospheric radio-cesium samples were obtained at a site in polluted area in Fukushima in september, 2017, on a quartz fiber filters using high volume air samplers. The radioactivty were measured with Ge-detercters, and number and volume of bioaerosols were estimeted using optical/fluorescence microscope. Radioactivity of cesium included in fungal spore was measured with fungi sampled around the observation sites. The atmospheric radio-cesium activity showed a good positive colleration with the nu,ber and volume of the bioarerosols.