Quantifying the dilution of the radiocesium contamination in Fukushima coastal river sediment (2011-2015).
Fallout from the Fukushima Dai-ichi nuclear power plant accident resulted in a 3000-km2radioactive contamination plume. Here, we model the progressive dilution of the radiocesium contamination in 327 sediment samples from two neighboring catchments with different timing of soil decontamination. Overall, we demonstrate that there has been a ~90% decrease of the contribution of upstream contaminated soils to sediment transiting the coastal plains between 2012 (median - M - contribution of 73%, mean absolute deviation - MAD - of 27%) and 2015 (M 9%, MAD 6%). The occurrence of typhoons and the progress of decontamination in different tributaries of the Niida River resulted in temporary increases in local contamination. However, the much lower contribution of upstream contaminated soils to coastal plain sediment in November 2015 demonstrates that the source of the easily erodible, contaminated material has potentially been removed by decontamination, diluted by subsoils, or eroded and transported to the Pacific Ocean.
Laboratoire des Sciences du Climat et de l'Environnement (LSCE/IPSL), Unité Mixte de Recherche 8212 (CEA/CNRS/UVSQ), Université Paris-Saclay, Gif-sur-Yvette (France).
Olivier
O
Evrard
Laboratoire des Sciences du Climat et de l'Environnement (LSCE/IPSL), Unité Mixte de Recherche 8212 (CEA/CNRS/UVSQ), Université Paris-Saclay, Gif-sur-Yvette (France).
J Patrick
JP
Laceby
Center for Research in Isotopes and Environmental Dynamics (CRIED), University of Tsukuba, Tsukuba (Japan).
Yuichi
Y
Onda
Institute of Environmental Radioactivity (IER), University of Fukushima, Fukushima (Japan).
Yoshifumi
Y
Wakiyama
Laboratoire des Sciences du Climat et de l'Environnement (LSCE/IPSL), Unité Mixte de Recherche 8212 (CEA/CNRS/UVSQ), Université Paris-Saclay, Gif-sur-Yvette (France).
Hugo
H
Jaegler
Laboratoire des Sciences du Climat et de l'Environnement (LSCE/IPSL), Unité Mixte de Recherche 8212 (CEA/CNRS/UVSQ), Université Paris-Saclay, Gif-sur-Yvette (France).
Irène
I
Lefèvre
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26051754
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26026933
Environ Pollut. 2016 Jan;208(Pt B):562-70
26561453
J Environ Radioact. 2015 Oct;148:92-110
26142817
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24694549
J Environ Radioact. 2015 Jan;139:362-9
25113169
J Environ Radioact. 2013 Apr;118:96-104
23274616
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22084070
J Environ Radioact. 2013 Oct;124:121-9
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23000550
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24429978
J Environ Radioact. 2009 Sep;100(9):774-8
18950908
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23995073
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24165695
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