Article
Oceanography
Ohtsuki Satoru, Shirotani Yuhei, Takata Hyoe
Summary: We investigated the dynamics of tritium (H-3) in the marine environment off Aomori and Iwate prefectures from 2003 to 2012. By comparing H-3 and Cs-137 in collected samples, we found that the concentration of tritium in marine biota was similar to that in seawater, indicating a lack of accumulation in marine biota. However, Cs-137 was found to be accumulated at relatively high levels. The lack of correlation between the dynamics of tritium and Cs-137 in three different species provides convincing evidence for their decoupling in marine ecology.
JOURNAL OF OCEANOGRAPHY
(2023)
Article
Nuclear Science & Technology
Yuhei Shirotani, Naohiko Inatomi, Kiriko Miyamoto, Masatoshi Yamada, Masashi Kusakabe
Summary: Analysis of tritium radioactivity concentration monitoring data in the coastal waters off Rokkasho revealed an increase in H-3 concentration during the active test period from 2006 to 2008, followed by a continuous decline since then, with virtually no impact from the 2011 Fukushima Daiichi Nuclear Power Plant accident.
FUSION ENGINEERING AND DESIGN
(2021)
Article
Water Resources
Li Pu, Pei Xin, Xiayang Yu, Ling Li, D. A. Barry
Summary: Through laboratory experiments and numerical simulations, it was found that cold freshwater recharge performs better in mitigating seawater intrusion compared to hot water, which induces a marked overshoot of salinity distribution.
ADVANCES IN WATER RESOURCES
(2021)
Article
Environmental Sciences
Isak Holmerin, Filip Svensson, Toru Hirawake, Takashi Ishimaru, Yukari Ito, Jota Kanda, Francisco Nascimento, Clare Bradshaw
Summary: After the Fukushima nuclear plant accident, Cs-137 had a longer ecological half-life in demersal fish compared to pelagic fish. This study investigated the hypothesis that an unexplored food web structure could explain the prolonged half-life of Cs-137 in benthic flatfish, and found that benthic organisms could be a continuous source of Cs-137 for demersal fish.
JOURNAL OF ENVIRONMENTAL RADIOACTIVITY
(2022)
Article
Environmental Sciences
Hyoe Takata
Summary: This study compared the spatial and temporal distributions of 137Cs in the European Baltic Sea and the North and Norwegian Seas after the Chernobyl accident, and in Japanese coastal regions after the Fukushima accident. The results showed that the decrease in 137Cs concentrations largely depended on local geography, and the dilution-diffusion effect of seawater was more significant in Japanese coastal waters.
JOURNAL OF ENVIRONMENTAL RADIOACTIVITY
(2022)