Atmospheric Fallout of 129I in Japan before the Fukushima Accident: Regional and Global Contributions (1963鈥?005)

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• 作者：Chiaki Toyama ; Yasuyuki Muramatsu ; Yasuhito Igarashi ; Michio Aoyama ; Hiroyuki Matsuzaki
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2013
• 出版时间：August 6, 2013
• 年：2013
• 卷：47
• 期：15
• 页码：8383-8390
• 全文大小：421K
• 年卷期：v.47,no.15(August 6, 2013)
• ISSN：1520-5851

文摘

Atmospheric ¹²⁹I deposition was studied in different locations of Japan (Akita, Tsukuba, Tokyo, and Ishigaki Island) with samples collected between 1963 and 2005 in order to understand the distribution and sources of this nuclide and provide a reference deposition level prior to the Fukushima accident. Over this time period, the deposition pattern of ¹²⁹I in Tsukuba and Tokyo (on the Pacific side) differed from that of Akita (on the Japan Sea side). The primary source of deposition in Tsukuba and Tokyo is related to the ¹²⁹I discharge from domestic reprocessing in Tokai-mura. In contrast, the time-series pattern of deposition in Akita seems to have been influenced by ¹²⁹I discharges from reprocessing facilities in Europe and the transport of this radionuclide by westerly winds to coastlines of the Japan Sea. The ¹²⁹I deposition in Ishigaki (one of the southernmost islands in Japan) is influenced primarily by oceanic air masses (easterly winds), and deposition was 1 order of magnitude lower than that observed in Tsukuba and Tokyo. Cumulative ¹²⁹I deposition in Tokyo before the Fukushima accident was estimated at 13 mBq/m². The results of this study on deposition contribute to understanding the deposition levels of ¹²⁹I prior to the accident.