Fukushima-derived radiocesium in the western subarctic area of the North Pacific Ocean, Bering Sea, and Arctic Ocean in 2019 and 2020

Yuichiro Kumamoto; Michio Aoyama; Yasunori Hamajima; Mutsuo Inoue; Shigeto Nishino; Takashi Kikuchi; Akihiko Murata; Kazutoshi Sato

doi:10.1016/j.jenvrad.2022.106949

Fukushima-derived radiocesium in the western subarctic area of the North Pacific Ocean, Bering Sea, and Arctic Ocean in 2019 and 2020

J Environ Radioact. 2022 Oct:251-252:106949. doi: 10.1016/j.jenvrad.2022.106949. Epub 2022 Jun 21.

Authors

Yuichiro Kumamoto¹, Michio Aoyama², Yasunori Hamajima³, Mutsuo Inoue⁴, Shigeto Nishino⁵, Takashi Kikuchi⁶, Akihiko Murata⁷, Kazutoshi Sato⁸

Affiliations

¹ Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, 2-15 Natushima-cho, Yokosuka, Kanagawa, 2370061, Japan. Electronic address: kumamoto@jamstec.go.jp.
² Center for Research in Isotopes and Environmental Dynamics, University of Tsukuba, Tsukuba, 3058577, Japan; Institute of Environmental Radioactivity, Fukushima University, Fukushima, 9601296, Japan. Electronic address: michio.aoyama@ied.tsukuba.ac.jp.
³ Low Level Radioactivity Laboratory, Kanazawa University, Wake, Nomi, Ishikawa, 9231224, Japan. Electronic address: hamajima@se.kanazawa-u.ac.jp.
⁴ Low Level Radioactivity Laboratory, Kanazawa University, Wake, Nomi, Ishikawa, 9231224, Japan. Electronic address: i247811@staff.kanazawa-u.ac.jp.
⁵ Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, 2-15 Natushima-cho, Yokosuka, Kanagawa, 2370061, Japan. Electronic address: nishinos@jamstec.go.jp.
⁶ Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, 2-15 Natushima-cho, Yokosuka, Kanagawa, 2370061, Japan. Electronic address: takashik@jamstec.go.jp.
⁷ Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, 2-15 Natushima-cho, Yokosuka, Kanagawa, 2370061, Japan. Electronic address: murataa@jamstec.go.jp.
⁸ Faculty of Engineering, Kitami Institute of Technology, Kitami, 0908507, Japan. Electronic address: satokazu@mail.kitami-it.ac.jp.

PMID: 35749953
DOI: 10.1016/j.jenvrad.2022.106949

Abstract

We measured dissolved radiocesium (¹³⁴Cs and ¹³⁷Cs) in surface seawater collected in the western subarctic area of the North Pacific Ocean, Bering Sea, and Arctic Ocean in 2019 and 2020. The radiocesium released from the accident of the Fukushima Dai-ichi nuclear power plant (FNPP1) in 2011 was still observed in these areas (∼2 Bq m^-3 decay-corrected to the date of the accident). In 2019/2020, the FNPP1-derived radiocesium concentrations in the Bering Sea and the Chukchi Sea, which is a marginal sea of the Arctic Ocean connecting the Bering Sea to the Arctic Ocean, were within the range of those observed in 2017/2018. On the other hand, the FNPP1-derived radiocesium was detected in the Arctic Ocean farther north of the Chukchi Sea in 2019/2020 for the first time. This was probably derived from the long-range transport of the FNPP1-derived radiocesium from the North Pacific coastal area of Japan to the Arctic Ocean through the Bering Sea during the past decade. The transport of the FNPP1-derived radiocesium from the Bering Sea to the western subarctic area in 2019/2020 is not clear, which implies the retainment of the FNPP1-derived radiocesium within the Bering Sea.

Keywords: (134)Cs; (137)Cs; Fukushima Dai-ichi nuclear power plant accident; Subarctic gyre; Surface currents.

MeSH terms

Cesium Radioisotopes / analysis
Fukushima Nuclear Accident*
Japan
Nuclear Power Plants
Pacific Ocean
Radiation Monitoring*
Water Pollutants, Radioactive* / analysis

Substances

Cesium Radioisotopes
Water Pollutants, Radioactive