TY - JOUR
T1 - Iodine isotopes in precipitation: Four-year time series variations before and after 2011 Fukushima nuclear accident
AU - Xu, Sheng
AU - Zhang, Luyuan
AU - Freeman, Stewart P. H. T.
AU - Hou, Xiaolin
AU - Watanabe, Akira
AU - Sanderson, David C. W.
AU - Cresswell, Alan
AU - Yamaguchi, Katsuhiko
PY - 2016
Y1 - 2016
N2 - Rainwater samples were collected monthly from Fukushima, Japan, in 2012-2014 and analysed for 127I and 129I. These are combined with previously reported data to investigate atmospheric levels and behaviour of Fukushima-derived 129I before and after the 2011 nuclear accident. In the new datasets, 127I and 129I concentrations between October 2012 and October 2014 varied from 0.5 to 10 μg/L and from 1.2 × 108 to 6.9 × 109 atoms/L respectively, resulting in 129I/127I atomic ratio ranges from 3 × 10-8 to 2 × 10-7. The 127I concentrations were in good agreement with those in the previous period from March 2011 to September 2012, whereas the 129I concentrations and 129I/127I ratios followed declining trends since the accident. Although 129I concentrations in five samples during the period of 2013-2014 have approached the pre-accident levels, 129I concentrations in most samples remained higher values in winter and spring-summer. The high 129I 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 129I from contaminated soil and water, respectively. Long-term declining rate suggests that contribution of the Fukushima-derived 129I to the atmosphere would become less since 2014.
AB - Rainwater samples were collected monthly from Fukushima, Japan, in 2012-2014 and analysed for 127I and 129I. These are combined with previously reported data to investigate atmospheric levels and behaviour of Fukushima-derived 129I before and after the 2011 nuclear accident. In the new datasets, 127I and 129I concentrations between October 2012 and October 2014 varied from 0.5 to 10 μg/L and from 1.2 × 108 to 6.9 × 109 atoms/L respectively, resulting in 129I/127I atomic ratio ranges from 3 × 10-8 to 2 × 10-7. The 127I concentrations were in good agreement with those in the previous period from March 2011 to September 2012, whereas the 129I concentrations and 129I/127I ratios followed declining trends since the accident. Although 129I concentrations in five samples during the period of 2013-2014 have approached the pre-accident levels, 129I concentrations in most samples remained higher values in winter and spring-summer. The high 129I 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 129I from contaminated soil and water, respectively. Long-term declining rate suggests that contribution of the Fukushima-derived 129I to the atmosphere would become less since 2014.
KW - 129I/127I
KW - Fukushima nuclear accident
KW - Fukushima-derived 129I
KW - Long-term variation
KW - Rainwater
U2 - 10.1016/j.jenvrad.2016.02.011
DO - 10.1016/j.jenvrad.2016.02.011
M3 - Journal article
C2 - 26913975
SN - 0265-931X
VL - 155-156
SP - 38
EP - 45
JO - Journal of Environmental Radioactivity
JF - Journal of Environmental Radioactivity
ER -