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; Naoki Shirai; Yoshiyasu Nagakawa; Nomoru Sakurai; Hiromitsu Haba; Hiroyuki Matsuzaki; Haruo Tsuruta; Yuichi Moriguchi

doi:10.1016/j.jenvrad.2019.106000

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

J Environ Radioact. 2019 Nov:208-209:106000. doi: 10.1016/j.jenvrad.2019.106000. Epub 2019 Jul 3.

Authors

Mitsuru Ebihara¹, Yasuji Oura², Naoki Shirai², Yoshiyasu Nagakawa³, Nomoru Sakurai³, Hiromitsu Haba⁴, Hiroyuki Matsuzaki⁵, Haruo Tsuruta⁶, Yuichi Moriguchi⁷

Affiliations

¹ Department of Chemistry, Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo, 192-0397, Japan; Department of Earth Sciences, Waseda University, 1-6-1 Nishi-waseda, Shinjuku-ku, Tokyo, 169-8050, Japan. Electronic address: ebiharamitsuru@aoni.waseda.jp.
² Department of Chemistry, Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo, 192-0397, Japan.
³ Biotechnology Group, Tokyo Metropolitan Industrial Technology Research Institute, 2-4-10 Aomi, Koto-ku, Tokyo, 135-0064, Japan.
⁴ Nishina Center for Accelerator-Based Science, RIKEN, Wako, Saitama, 351-0198, Japan.
⁵ Department of Nuclear Engineering and Management, School of Engineering, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan.
⁶ Remote Sensing Technology Center of Japan, 3-17-1 Toranomon, Minato-ku, Tokyo, 105-0001, Japan.
⁷ Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.

PMID: 31279226
DOI: 10.1016/j.jenvrad.2019.106000

Abstract

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.

Keywords: (129)I; (131)I; Airborne particulate matter; Fukushima nuclear accident.

MeSH terms

Air Pollutants, Radioactive / analysis*
Fukushima Nuclear Accident
Iodine Radioisotopes / analysis*
Particulate Matter / analysis*
Radiation Monitoring

Substances

Air Pollutants, Radioactive
Iodine Radioisotopes
Particulate Matter