A new approach for reconstructing the 131I-spreading due to the 2011 Fukushima nuclear accident by means of measuring 129I in airborne particulate matter

Mitsuru Ebihara*, Yasuji Oura, N. Shirai, Yoshiyasu Nagakawa, Nomoru Sakurai, Hiromitsu Haba, Hiroyuki Matsuzaki, H. Tsuruta, Yuichi Moriguchi

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


To retrieve the diffusion trajectory of the 131I dispersed in the environment by the nuclear power plant accident in Fukushima in 2011, airborne particulate matter (APM) samples collected in the Tokyo metropolitan area were analyzed for their 129I contents by means of accelerator mass spectrometry. In evaluating blank levels of chemicals and filters used for collecting APM, we established the analytical procedure for determining the 129I activity of as low as 10−8 Bq for a small piece of filter samples (about 0.1 cm2). Coupled with 131I data determined just after the accident, activity ratios of 129I/131I were obtained with a mean value of 2.29 × 10−8 (±28% of a standard deviation). This value is systematically smaller than a mean value of soil samples by 16–24% and the inventory data by 27%, suggesting that 129I was partly lost from APM. As 129I can be a proxy of 131I for APM, it is possible to trace how 131I in the particulate phase spread in eastern Japan and, furthermore, evaluate the internal radiation exposure due to 131I by inhalation of 131I-containing airborne particulates.

Original languageEnglish
Article number106000
JournalJournal of Environmental Radioactivity
Publication statusPublished - 2019 Nov


  • Airborne particulate matter
  • Fukushima nuclear accident
  • I
  • I

ASJC Scopus subject areas

  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution
  • Health, Toxicology and Mutagenesis


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