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Research article - Peer-reviewed, 2021

Distribution of engineered Ag nanoparticles in the aquatic-terrestrial transition zone: a long-term indoor floodplain mesocosm study

Metreveli, George; Kurtz, Sandra; Rosenfeldt, Ricki R.; Seitz, Frank; Kumahor, Samuel K.; Grun, Alexandra; Klitzke, Sondra; Vogel, Hans-Jorg; Bundschuh, Mirco; Baumann, Thomas; Schulz, Ralf; Manz, Werner; Lang, Friederike; Schaumann, Gabriele E.

Abstract

The fate of engineered nanoparticles in the aquatic-terrestrial transition zone is decisive for their effect in the environment. However, our knowledge on processes within this interface is rather low. Therefore, we used a floodplain stream mesocosm to enhance our understanding of the long-term distribution and biological effects of citrate-coated silver nanoparticles (Ag-NPs) in this ecosystem. Parallel to pulsed dosing of Ag-NPs, we observed fluctuating but successively increasing concentrations of aqueous Ag, 88-97% of which was categorized as particles. The remaining dissolved fraction was mainly complexed with natural organic matter (NOM). The major Ag fraction (50%) was associated with the uppermost sediment layer. The feeding activity of benthic amphipods was largely unaffected, which could be explained by the low Ag concentration and complexation of released Ag+ with NOM. According to our hypothesis, only a small nanoparticle fraction (6%) moved to the terrestrial area due to aquatic aging and enrichment of Ag-NPs in sediments and biota. Nanoparticle infiltration in deeper sediment and soil layers was also limited. We expect that a small fraction of nanoparticles remaining in the water for several weeks can be transported over large distances in rivers. The Ag-NPs accumulated in the top layer of sediment and soil may serve as a source of toxic Ag+ ions or may be remobilized due to changing physico-chemical conditions. Furthermore, the high enrichment of Ag-NPs on algae (up to 250 000-fold) and leaves (up to 11 000-fold) bears risk for organisms feeding on those resources and for the transfer of Ag within the food web.

Published in

Environmental Science: Nano
2021, number: 6, pages: 1771-1785
Publisher: ROYAL SOC CHEMISTRY

    Sustainable Development Goals

    SDG6 Clean water and sanitation

    UKÄ Subject classification

    Environmental Sciences

    Publication identifier

    DOI: https://doi.org/10.1039/d1en00093d

    Permanent link to this page (URI)

    https://res.slu.se/id/publ/112111