Ten-year temporal changes in the supply source of Cs released by the Fukushima Daiichi Nuclear Power Plant to the coastal area

Sato, Shun; Wakiyama, Yoshifumi*; Takahashi, Fumiaki; Takata, Hyoe*

Science of the Total Environment, 1000, p.180380_1 - 180380_14, 2025/10

https://doi.org/10.1016/j.scitotenv.2025.180380

We compared the ongoing direct release of Cs from the Fukushima Daiichi Nuclear Power Plant (FDNPP) and riverine inputs of Cs that have contributed to the persistent elevated Cs in coastal waters around the plant since 2012. The direct release of Cs clearly decreased from 17.5 TBq during 20122014 to 0.6 TBq during 20192021 because of measures implemented by the FDNPP. The riverine input decreased slightly from 2.2 TBq during 20122014 to 2.0 TBq during 20192021. The ratio of direct release to the total Cs flux into the coastal water around the FDNPP decreased from 89% during 20122014 to 23% during 20192021. This change resulted in part from a lowering of the limit of detection of Cs activities to avoid overestimation of Cs fluxes from the facility, but also from installation of an impermeable seaside wall. The trend of decreasing riverine Cs input might have been due entirely to environmental remediation. Our results indicate that the contribution of riverine input to the coastal waters will continue for a long time. Precise prediction of the long-term distribution of Cs in the marine environment will require consideration of a variety of environmental factors and anthropogenic effects.

Impacts of freeze-thaw processes and subsequent runoff on Cs washoff from bare land in Fukushima

Igarashi, Yasunori*; Onda, Yuichi*; Wakiyama, Yoshifumi*; Yoshimura, Kazuya; Kato, Hiroaki*; Kozuka, Shohei*; Manome, Ryo*

Science of the Total Environment, 769, p.144706_1 - 144706_9, 2021/05

https://doi.org/10.1016/j.scitotenv.2020.144706

Radionuclides from the Fukushima Daiichi Nuclear Power Plant in terrestrial systems

Onda, Yuichi*; Taniguchi, Keisuke*; Yoshimura, Kazuya; Kato, Hiroaki*; Takahashi, Junko*; Wakiyama, Yoshifumi*; Coppin, F.*; Smith, H.*

Nature Reviews Earth & Environment (Internet), 1(12), p.644 - 660, 2020/12

https://doi.org/10.1038/s43017-020-0099-x

Effect of topsoil removal and selective countermeasures on radiocesium accumulation in rice plants in Fukushima paddy field

Yang, B.*; Onda, Yuichi*; Omori, Yoshihiro*; Sekimoto, Hitoshi*; Fujiwara, Toru*; Wakiyama, Yoshifumi*; Yoshimura, Kazuya; Takahashi, Junko*; Sun, X.*

Science of the Total Environment, 603-604, p.49 - 56, 2017/12

https://doi.org/10.1016/j.scitotenv.2017.06.026

Behavior of accidentally released radiocesium in soil-water environment; Looking at Fukushima from a Chernobyl perspective

Konoplev, A.*; Golosov, V.*; Laptev, G.*; Namba, Kenji*; Onda, Yuichi*; Takase, Tsugiko*; Wakiyama, Yoshifumi*; Yoshimura, Kazuya

Journal of Environmental Radioactivity, 151(Part 3), p.568 - 578, 2016/01

https://doi.org/10.1016/j.jenvrad.2015.06.019

Seasonality of Cs-137 concentration of sediments eroded from a slope in Fukushima

Wakiyama, Yoshifumi*; Manome, Ryo*; Onda, Yuichi*; Yoshimura, Kazuya

no journal, , 

The Impact and fate of fallout radionuclides by Fukushima Daiichi Nuclear Power Plant Accident in hydrological systems and post-accident environmental recovery

Onda, Yuichi*; Taniguchi, Keisuke*; Yoshimura, Kazuya; Wakiyama, Yoshifumi*

no journal, , 

Spatial and vertical distribution of radiocesium in marine sediment cores of Fukushima Prefecture

Chaboche, P.-A.*; Wakiyama, Yoshifumi*; Takata, Hyoe*; Wada, Toshihiro*; Misono, Toshiharu; Shiribiki, Takehiko; Funaki, Hironori

no journal, , 

The Fukushima Daiichi Nuclear Power Plant (FDNPP) incident, triggered by the Great East Japan Earthquake and subsequent tsunami in March 2011, resulted in the release of significant quantities of radionuclides into the terrestrial and marine environments of Fukushima Prefecture. While the activity of radiocesium (i.e., Cs and Cs) in these environments has decreased since the accident, continuous inputs through rivers draining and eroding the main terrestrial radioactive plume have been measured, maintaining elevated levels of Cs in riverine and coastal sediment deposited off the Prefecture's coast. Consequently, identifying the sources of sediment is required to elucidate the links between terrestrial and marine radiocesium dynamics and to anticipate the fate of persistent radionuclides in the environment.

Cesium-137 wash-off associated with soil erosion on various land uses in Fukushima

Yoshimura, Kazuya; Wakiyama, Yoshifumi*; Onda, Yuichi*; Takase, Tsugiko*

no journal, , 

Identifying the riverine sources of sediment and associated radiocaesium deposited off the coast of Fukushima Prefecture

Chaboche, P.-A.*; Wakiyama, Yoshifumi*; Takata, Hyoe*; Wada, Toshihiro*; Evrard, O.*; Misono, Toshiharu; Shiribiki, Takehiko; Funaki, Hironori

no journal, ,