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

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

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)1771-1785
Number of pages15
JournalEnvironmental Science: Nano
Volume8
Issue number6
DOIs
Publication statusPublished - Jun 2021
Externally publishedYes

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