Zinc pollution in zones dominated by algae and submerged macrophytes in Lake Taihu
Zinc (Zn) contamination in lake zones dominated by algae and macrophytes in Lake Taihu was analyzed through diffusive gradient in thin films (DGT) and dialysis (HR-Peeper) methods. It was found that in both zones Zn contamination varied by season. In July and October, dissolved Zn was present in hig...
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Veröffentlicht in: | The Science of the total environment 2019-06, Vol.670, p.361-368 |
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Sprache: | eng |
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Zusammenfassung: | Zinc (Zn) contamination in lake zones dominated by algae and macrophytes in Lake Taihu was analyzed through diffusive gradient in thin films (DGT) and dialysis (HR-Peeper) methods. It was found that in both zones Zn contamination varied by season. In July and October, dissolved Zn was present in high concentrations, and in July, high concentrations of labile Zn were found in sediments. In July, reductive dissolutions of Fe/Mn oxides likely played a key role in the release of Zn, which was confirmed by both zones having the lowest percentage of the reducible fraction of Zn in July. Complexation of dissolved organic matter (DOM) with Zn may be responsible for the observed increase in the dissolved Zn concentration in October. This conclusion was supported by noting that October had the highest percentages of Zn-DOM complexes (25.3% and 34.4%) in the algae- and macrophytes-dominated zones, respectively. However, in January, low dissolved and labile Zn contents were observed in sediments in the two zones, suggesting that the decrease of Zn in sediments was caused by the adsorption of Fe/Mn oxides.
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•Zinc mobility showed a seasonal variation in both algae- and macrophyte-dominated zones.•In summer, Fe/Mn redox reduction increased Zn mobility in two different zones.•In autumn, DOM complexation increased Zn mobility in two different zones.•In winter, the Zn mobility was decreased by Fe/Mn oxide absorption in two different zones. |
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ISSN: | 0048-9697 1879-1026 |
DOI: | 10.1016/j.scitotenv.2019.03.167 |