The Kuroshio radiocesium stream

Chen-Tung Arthur Chen; Ting-Hsuan Huang; Wei-Jen Huang; Yiing-Jang Yang; Sen Jan; Ming-An Lee; Ming-Ta Lee

doi:10.1016/j.marpolbul.2022.114026

The Kuroshio radiocesium stream

Mar Pollut Bull. 2022 Sep:182:114026. doi: 10.1016/j.marpolbul.2022.114026. Epub 2022 Aug 10.

Authors

Chen-Tung Arthur Chen¹, Ting-Hsuan Huang², Wei-Jen Huang³, Yiing-Jang Yang⁴, Sen Jan⁴, Ming-An Lee⁵, Ming-Ta Lee⁶

Affiliations

¹ Department of Oceanography, National Sun Yat-sen University, Kaohsiung 804, Taiwan. Electronic address: ctchen@mail.nsysu.edu.tw.
² Taiwan Ocean Research Institute, National Applied Research Laboratories, Kaohsiung 801, Taiwan.
³ Department of Oceanography, National Sun Yat-sen University, Kaohsiung 804, Taiwan.
⁴ Institute of Oceanography, National Taiwan University, Taipei 106, Taiwan.
⁵ Department of Environmental Biology and Fisheries Science, National Taiwan Ocean University, Keelung 202, Taiwan.
⁶ Radiation Monitoring Center, Atomic Energy Council, Kaohsiung 833, Taiwan.

PMID: 35963224
DOI: 10.1016/j.marpolbul.2022.114026

Abstract

The Fukushima accident released short-lived Cs-134 and longer-lived Cs-137 to the ocean. The amount, although substantial, is much less than that produced during the atomic bomb tests 60 years ago. But, the latter has received little attention. Here we found only Cs-137 in waters near the origin of the Kuroshio. The speed of the Kuroshio current generally decreases with water depth, yet, the Cs-137 activity increases with depth to reach a subsurface maximum of 2.4 Bq m^-3. As a result, a core of high Cs-137 flux, or a radiocesium stream, exists at approximately 200-400 m in depth. In total, the Kuroshio transports about 1 PBq year^-1 Cs-137 northward between 121 and 123°E, 1000 times more than the 0.73-1.0 TBq year^-1 discharged to the ocean at Fukushima in 2016-2018.

Keywords: Cs-137; Fukushima accident; Kuroshio; Kuroshio Recirculation; Radiocesium stream; Subtropical Mode Water.

MeSH terms

Cesium Radioisotopes / analysis
Fukushima Nuclear Accident*
Japan
Radiation Monitoring*
Rivers
Water Pollutants, Radioactive* / analysis

Substances

Cesium Radioisotopes
Water Pollutants, Radioactive
Cesium-137
Cesium-134