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Influential factors of long-term and seasonal 137 Cs change in agricultural and forested rivers: Temperature, water quality and an intense Typhoon Event.

Authors :
Tsuji H
Nishikiori T
Ito S
Ozaki H
Watanabe M
Sakai M
Ishii Y
Hayashi S
Source :
Environmental pollution (Barking, Essex : 1987) [Environ Pollut] 2023 Dec 01; Vol. 338, pp. 122617. Date of Electronic Publication: 2023 Sep 25.
Publication Year :
2023

Abstract

In this study, the effect of temperature, water quality, and the impact of an intense typhoon event on change in <superscript>137</superscript> Cs concentration in the water of agricultural and forested rivers near the Fukushima Daiichi nuclear power plant (Japan) was evaluated using monthly stationary observations obtained under baseflow conditions 2.8-10.6 years after the nuclear accident in 2011. The dissolved <superscript>137</superscript> Cs concentration fluctuated seasonally with water temperature in all rivers, and the increase in dissolved <superscript>137</superscript> Cs concentration for unit increase in temperature was higher in forested rivers than in agricultural rivers. The relationship between water temperature and the apparent distribution coefficient of <superscript>137</superscript> Cs well followed the van 't Hoff equation in the two agricultural rivers, where the enthalpy of reaction was estimated as -15.6 and -19.6 kJ mol <superscript>-1</superscript> . The van 't Hoff equation was not well followed for a forested river, where the suspended solids mainly comprised organic matter, suggesting that the dominant process determining dissolved <superscript>137</superscript> Cs concentrations in forested rivers is not only water temperature effect on ion exchange, but rather the input of <superscript>137</superscript> Cs and K <superscript>+</superscript> (competing with <superscript>137</superscript> Cs for exchange sites on mineral particles) into the water phase via litter leaching. Suspended solids concentrations in agricultural rivers correlated negatively with <superscript>137</superscript> Cs concentrations in suspended solids, suggesting an increased proportion of coarse particles or the input of soils with low <superscript>137</superscript> Cs concentration from decontaminated agricultural land. At some sites, <superscript>137</superscript> Cs concentrations in dissolved form and in suspended solids were reduced sharply in association with the passage of Typhoon Hagibis in October 2019, suggesting that Typhoon Hagibis caused large-scale surface erosion that removed the source of <superscript>137</superscript> Cs.<br />Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.<br /> (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Details

Language :
English
ISSN :
1873-6424
Volume :
338
Database :
MEDLINE
Journal :
Environmental pollution (Barking, Essex : 1987)
Publication Type :
Academic Journal
Accession number :
37757931
Full Text :
https://doi.org/10.1016/j.envpol.2023.122617