Atmospheric resuspension of insoluble radioactive cesium bearing particles found in the difficult-to-return area in Fukushima

Tang, P.*; Kita, Kazuyuki*; Igarashi, Yasuhito*; Satou, Yukihiko; Hatanaka, Kotaro*; Adachi, Koji*; Kinase, Takeshi*; Ninomiya, Kazuhiko*; Shinohara, Atsushi*

Progress in Earth and Planetary Science (Internet), 9(1), p.17_1 - 17_15, 2022/03

https://doi.org/10.1186/s40645-022-00475-6

Role of advection in atmospheric ammonia; A Case study at a Japanese lake basin influenced by agricultural ammonia sources

Kubota, Tomohiro; Kuroda, Hisao*; Watanabe, Mirai*; Takahashi, Akiko*; Nakazato, Ryoji*; Tarui, Mika*; Matsumoto, Shunichi*; Nakagawa, Keita*; Numata, Yasuko*; Ouchi, Takao*; et al.

Atmospheric Environment, 243, p.117856_1 - 117856_9, 2020/12

https://doi.org/10.1016/j.atmosenv.2020.117856

The dry and wet depositions of atmospheric ammonia (NH) is one of the important pathways of nitrogen loads to aquatic ecosystems. Crop and livestock agriculture, one of the largest emitters of NH in Asian countries, are known to cause high spatial and seasonal variation of NH and influence the surrounding lake basin areas via its dry and wet deposition. However, the spatial characteristics of the NH concentration in basin scale are not completely understood for regulation in NH emission. Here we aim to clarify dominant factors of spatial and seasonal variations of the NH concentration in a eutrophic lake basin surrounded by agricultural areas in Japan. Passive sampling over various land use categories in the basin was conducted at 36 sites in total from October 2018 to January 2020. Interestingly, the observed NH concentration near the livestock houses were higher in winter than summer, which was inconsistent with knowledge of seasonal changes of current NH emission inventory based on temperature-driven volatilization process. Comparing monthly NH concentrations with various meteorological factors, we suggested the importance of seasonal advection of NH from high emission sources to which has been rarely paid attention by the previous past studies. As for this, should be considered for lake ecosystem management since deposition of NH is known to be closely related to the ecological processes such as phytoplankton blooming.

A Review of Cs-bearing microparticles in the environment emitted by the Fukushima Dai-ichi Nuclear Power Plant accident

Igarashi, Yasuhito*; Kogure, Toshihiro*; Kuribara, Yuichi; Miura, Hikaru*; Okumura, Taiga*; Satou, Yukihiko; Takahashi, Yoshio*; Yamaguchi, Noriko*

Journal of Environmental Radioactivity, 205-206, p.101 - 118, 2019/09

https://doi.org/10.1016/j.jenvrad.2019.04.011

Scientists face challenge in identifying the radioactive materials which are found as dotted images on various imaging plate (IP) autoradiographic photos of radioactively contaminated materials by the Fukushima Dai-ichi Nuclear Power Plant (F1NPP, or FDNPP) accident, such as air filter, fugitive dust, surface soil, agricultural materials, and water-shed samples. It has been revealed that they are minute particles with distinct morphology and elemental composition with high specific radioactivity, and different from those of the so-called Chernobyl hot particles. Basically, they are glassy particles once molten, composed of Si, O, Fe, Zn etc. with highly concentrated radiocaesium, which can be called as radiocaesium-bearing microparticles (CsMP). At present, CsMP can be classified into two types, Types-A and -B, which are characterized by different specific radioactivity, Cs/Cs ratio, size and morphology, and geographic distribution around F1NPP. Such studies on the CsMP from various aspects have provided valuable information about what happened in the nuclear reactors during the F1NPP accident and fates of the CsMP in the environment. This review first provides a retrospective view on the research history of the CsMP, which is helpful to understand the unique character of the CsMP. Subsequently, more details about the current understanding of the natures of these hot particles, such as origin, morphology, chemical compositions, thermal properties, water-solubility, and secondary migration of CsMP in river and ocean systems are described with future prospects.

Investigation of the chemical characteristics of individual radioactive microparticles emitted from reactor 1 by the Fukushima Daiichi Nuclear Power Plant accident by using multiple synchrotron radiation X-ray analyses

Ono, Takahiro*; Iizawa, Yushin*; Abe, Yoshinari*; Nakai, Izumi*; Terada, Yasuko*; Satou, Yukihiko; Sueki, Keisuke*; Adachi, Koji*; Igarashi, Yasuhito*

Bunseki Kagaku, 66(4), p.251 - 261, 2017/04

https://doi.org/10.2116/bunsekikagaku.66.251

no abstracts in English

Characteristic of radioactive particles discovered from the near of Fukushima Dai-ichi Nuclear Power Plant

Satou, Yukihiko*; Sueki, Keisuke*; Sasa, Kimikazu*; Minowa, Haruka*; Yoshikawa, Hideki; Fujiwara, Kenso; Nakama, Shigeo; Adachi, Koji*; Igarashi, Yasuhito*

no journal, , 

Radioactive particle including high density cesium were released caused by the Fukushima Daiichi nuclear disaster. In this study, we analyzed distribution of radioactive particle and its characteristic about obtained soils and dusts. As a result, radioactive particles were confirmed from soil sample. In particular, 100 micro meter in diameters particles were found at the point of north-northwest direction approximately 7km from the nuclear power plant. Found particles resembled an elementary composition and surface state of the particle found in the 20km northwest from nuclear power plant and Tsukuba.

Measuring of surface potential of radiocaesium-bearing microparticles by Kelvin Probe Force Microscopy

Kurosawa, Keiichi*; Iwata, Ayumu*; Satou, Yukihiko; Abe, Yoshinari*; Igarashi, Yasuhito*; Okuda, Tomoaki*

no journal, , 

The Fukushima Daiichi Nuclear Power Plant accident caused serious emission of radionuclides into the atmosphere. After several years, insoluble radiocaesium-bearing microparticles (CsMP) have been found in some regions in Japan. These insoluble solid particles remain as a particle in human airways and continue emitting radiation when they are inhaled. Therefore, these particles have a potentially significant adverse effect on human health. Because of the continuous emission of the -rays, which is energetic electron beam, previous studies reported that the radioactive particles would have specific electrostatic charging characteristics. Also, several laboratory experiments and numerical simulations have shown that the electrostatically charged particles are more deposited on the human respiratory airway. Therefore, the electrostatic charging characterization of the CsMP is important for the accurate evaluation of its health effects. In this study, we used Kelvin Probe Force Microscopy to measure the surface potential of CsMP. The obtained mapping image was shown that the radioactive particle has a certain distribution of surface potential ranged between +0.3 V and -0.3 V. This distribution of the surface potential within the particle may be associated with the distribution of radioactive Cs in the surface layer of the particle.

Role of advection in atmospheric ammonia; A Case study at a Japanese lake basin influenced by agricultural ammonia sources

Katata, Genki*; Kubota, Tomohiro; Kuroda, Hisao*; Watanabe, Mirai*; Takahashi, Akiko*; Nakazato, Ryoji*; Tarui, Mika*; Matsumoto, Shunichi*; Nakagawa, Keita*; Numata, Yasuko*; et al.

no journal, , 

no abstracts in English

Can fungal spores explain atmospheric resuspension of radiocesium during warm season in Fukushima forest area?

Kita, Kazuyuki*; Hayashi, Naho; Igarashi, Yasuhito*; Hama, Kenzo*; Zaizen, Yuji*; Sekiyama, Tsuyoshi*; Adachi, Koji*; Yoshida, Naohiro*; Toyoda, Sakae*; Hosaka, Kentaro*; et al.

no journal, , 

no abstracts in English