Iodine isotopes in precipitation: temporal responses to 129I emissions from the Fukushima nuclear accident

Xu, S., Freeman, S. P.H.T. , Hou, X., Watanabe, A., Yamaguchi, K. and Zhang, L. (2013) Iodine isotopes in precipitation: temporal responses to 129I emissions from the Fukushima nuclear accident. Environmental Science and Technology, 47(19), pp. 10851-10859. (doi:10.1021/es401527q)

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The Fukushima Dai-ichi Nuclear Power Plant accident in 2011 has released a large amount of radionuclides to the atmosphere, and the radioactive plume has been dispersed to a large area in Europe and returned to Asia. To explore long-term trend of the Fukushima-derived radioactive plume and the behavior of harmful radioiodine in the atmosphere, long-term precipitation samples have been collected over 2010–2012 at Fukushima, Japan for determination of long-lived 129I. It was observed that 129I concentrations of 1.2 × 108 atom/L in 2010 before the accident dramatically increased by 4 orders of magnitude to 7.6 × 1011 atom/L in March 2011 immediately after the accident, with a 129I/127I ratio up to 6.9 × 10–5. Afterward, the 129I concentrations in precipitation decreased exponentially to 3 × 109 atom/L by October 2011 with a half-life of about 29 days. This declining trend of 129I concentrations in precipitation was interrupted around October 2011 by a new input of 129I to the atmosphere following a second exponential decrease. Such a cycle has occurred three times until the present. This temporal variation can be attributed to alternating 129I dispersion and resuspension from the contaminated local environment. A 129I/131I atomic ratio of 16 ± 1 obtained from rainwater samples is comparable with a value estimated for surface soil samples. 129I results from Denmark suggest an insignificant effect of 129I released from Fukushima to the 129I levels in Europe.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Xu, Dr Sheng and Freeman, Professor Stewart
Authors: Xu, S., Freeman, S. P.H.T., Hou, X., Watanabe, A., Yamaguchi, K., and Zhang, L.
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Environmental Science and Technology
Publisher:American Chemical Society
ISSN (Online):1520-5851

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