Abstract
The Fukushima accident released a large amount of 137Cs into the environment.In this study,we used a sediment core collected from the Chukchi Sea during the 2018 Arctic Xuelong Scientific Expedition to investigate the Fukushima accident-derived 137Cs.Using 210Pb(210Pbex)and 137Cs chronology,we find that the 137Cs peak at 2 cm corresponds to the year 2011±1.This implies that the Fukushima accident-derived137Cs arrived in the Chukchi Sea much earlier than that by oceanic current transport.Our three calculation results(sediment core deposition flux:(4.0±0.4)× 10-6 Bq cm-2 d-1;atmospheric deposition flux:(1.4-2.5)× 10-5 Bq cm-2 d-1;biological deposition flux:(4.0±0.9)×10-6 Bq cm-2 d-1)suggest that atmospheric deposition and biological transport could cause such peak records.The results indicate that the 2011 peak of 137Cs can serve as a new temporal marker for estimating the sedimentation rate in the region affected by the Fukushima accident.We state that assessing the impact of coastal accidents and subsequent wastewater discharge in marine environments needs more consideration of biological carryover in addition to physical oceanography transport.
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