JpGU-AGU Joint Meeting 2020

Presentation information

[J] Poster

A (Atmospheric and Hydrospheric Sciences ) » A-OS Ocean Sciences & Ocean Environment

[A-OS27] Chemical and Biological Oceanography

convener:Kazuhiro Misumi(Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry), Sayaka Yasunaka(Japan Agency for Marine-Earth Science and Technology)

[AOS27-P03] Radiocesium in the Kuroshio region and the Taiwan Strait from 2017 to 2018

*Wei-Jen Huang1, Chen-Tung Arthur Chen1, Ming-An Lee2, Sen Jan3, Yiing-Jang Yang3 (1.National Sun Yat-sen University, 2.National Taiwan Ocean University, 3.National Taiwan University)

Keywords:cesium-137, cesium-134, Fukushima

Anthropogenic radiocesium, such as, long half-lives 137Cs (30.2 yr) and short half-lives 134Cs (2.06 yr), were exported to the Pacific Ocean through atmospheric deposition and direct discharge by the global fallout from atmospheric nuclear weapons testing (which peaked in the early 1960s) and the Fukushima Daiichi nuclear power plants (FDNPPs) accident in 21 century. However, the spatial distribution of 137Cs and 134Cs around the Kuroshio Current and the Taiwan Strait is still unclear. This study collects near-surface waters (shallower than 5 m depth) and subsurface to deep waters (10 m to deeper than 200 m) to analyze 134Cs and 137Cs in the region among 116-123°E and 20-27°N from 2018 to 2019. The result displays that 134Cs activity in all samples was below the detection limit (0.6 Bq·m-3). The average of 137Cs activity in the near-surface water was 1.2±0.3 Bq·m-3 and was among the range reported by previous studies in the near-surface water at the western North Pacific Ocean. A maxima value of 137Cs in the subsurface water was 2.2 mBq·m-3 at 200 m depth. We analyze the water temperature, salinity, and density with 137Cs activity and suggest that the distribution of 137Cs activity was related to the water mass transportation in this study area.