AUTHOR=Lin Wuhui , Zhang Yibang , Du Jinqiu , Xuan Jiliang , Tuo Fei 

TITLE=Deciphering decadal observation of Fukushima-derived radiocesium in the most polluted port near the Fukushima Daiichi Nuclear Power Plant: from seawater to marine fish

JOURNAL=Frontiers in Marine Science

VOLUME=Volume 11 - 2024

YEAR=2024

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2024.1382229

DOI=10.3389/fmars.2024.1382229

ISSN=2296-7745

ABSTRACT=Biological concentration effect of radionuclides in marine fish has exacerbated public anxiety of seafood security in the context of Fukushima nuclear contaminated water discharging into the ocean. However, the most polluted port nearby Fukushima Daiichi Nuclear Power Plant (FDNPP) was seldom investigated, especially for radioactivity in marine fish. In this study, decadal observations of radiocesium in marine fish and seawater from the most polluted port were simultaneously established after Fukushima Nuclear Accident. We found a generally decreasing trend of historical 137 Cs activity in seawater with season variations that modulated by precipitation. Seasonal variations were delicately revealed and divided into exponential decline in dry season and steady variation in wet season. A novel method to estimate continuing source term of 137 Cs derived from FDNPP was proposed to be 3.9 PBq in 2011 and 19.3 TBq during 2012~2022 on the basis of historical 137 Cs.Biological concentration effect of marine fish is quantitatively emphasized according to higher ratio of over-standard for radiocesium in marine fish relative to that in seawater. Long-term observation and analysis of radiocesium in marine fish and seawater from the most polluted port would provide insights into scientific evaluation 2 of effectiveness of decommissioning of FDNPP in the past and share lessons on the fate of Fukushima-derived radionuclides in the future.