Iodine isotopes in precipitation: Four-year time series variations before and after 2011 Fukushima nuclear accident. (May 2016)

• Record Type: Journal Article
• Authors: Xu, Sheng; Zhang, Luyuan; Freeman, Stewart P.H.T.; Hou, Xiaolin; Watanabe, Akira; Sanderson, David C.W.; Cresswell, Alan; Yamaguchi, Katsuhiko
• Is Part Of: Journal of environmental radioactivity. Volume 155/156(2016:May)
• Page Start: 38
• Page End: 45
• Publication Date: 2016-05
• Subjects: Fukushima-derived 129I -- 129I/127I -- Long-term variation -- Rainwater -- Fukushima nuclear accident; Radioactivity -- Periodicals; Radiation, Background -- Periodicals; Radioecology -- Periodicals; Radioactive pollution -- Periodicals; Environmental Pollutants -- Periodicals; Radioactive Pollutants -- Periodicals; Radioactivity -- Periodicals; Radioécologie -- Périodiques; Pollution radioactive -- Périodiques; Fond de rayonnement -- Périodiques; 539.752
• DOI: 10.1016/j.jenvrad.2016.02.011
• Languages: English
• ISSNs: 0265-931X

Abstract

Abstract: Rainwater samples were collected monthly from Fukushima, Japan, in 2012–2014 and analysed for 127 I and 129 I. These are combined with previously reported data to investigate atmospheric levels and behaviour of Fukushima-derived 129 I before and after the 2011 nuclear accident. In the new datasets, 127 I and 129 I concentrations between October 2012 and October 2014 varied from 0.5 to 10 μg/L and from 1.2 × 10 8 to 6.9 × 10 9 atoms/L respectively, resulting in 129 I/ 127 I atomic ratio ranges from 3 × 10 −8 to 2 × 10 −7 . The 127 I concentrations were in good agreement with those in the previous period from March 2011 to September 2012, whereas the 129 I concentrations and 129 I/ 127 I ratios followed declining trends since the accident. Although 129 I concentrations in five samples during the period of 2013–2014 have approached the pre-accident levels, 129 I concentrations in most samples remained higher values in winter and spring-summer. The high 129 I levels in winter and spring-summer are most likely attributed to local resuspension of the Fukushima-derived radionuclide-bearing fine soil particles deposited on land surfaces, and re-emission through vegetation taking up 129 I from contaminated soil and water, respectively. Long-term declining rate suggests that contribution of the Fukushima-derived 129 I to the atmosphere would become less since 2014. Graphical abstract: Highlights: We measured 127 I and 129 I in rainwater samples from Fukushima in 2012–14. 129 I and 129 I/ 127 I followed declining trends since the 2011 accident. High 129 I was attributed to resuspension and re-emission of deposited 129 I. Fukushima-derived 129 I contributes less to the atmosphere since 2014.