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Research article - Peer-reviewed, 2022

Nanosized titanium dioxide elevates toxicity of cationic metals species for Daphnia - have aging and natural organic matter an unexpected impact?

Roy, Rajdeep; Kandrapu, Vinod Kumar; Kempter, Lucas; Islam, Rezaul; Kalcikova, Gabriela; Schulz, Ralf; Bundschuh, Mirco


In aquatic ecosystems, nanosized titanium dioxide particles (nTiO(2)) likely interact with natural organic matter (NOM) and may alter the ecotoxicity of co-occurring metals. The magnitude of changes in toxicity may be modulated by the duration of interactions (i.e. aging) between these factors. As those interactions are hardly addressed in literature, the present study aimed at assessing the impact of aging durations (0, 1, 3 and 6 days) on metals with mainly cationic (silver (Ag), cadmium (Cd)) or anionic (arsenic (As)) toxic ions in combination with three nTiO(2) levels (0.0, 0.6 and 3.0 mg/L) and two NOM levels (0 versus 8 mg TOC/L). The interaction of these factors was additionally investigated for two aging scenarios: in one scenario nTiO(2) were aged together with one of the metals, while in other scenario metals were added to aged nTiO(2). Subsequently, their combined acute effects on Daphnia magna were assessed. The results uncovered that nTiO(2) elevate the toxicity of metals with mainly cationic species (i.e. Ag+ and Cd2+) with the effect size depending on their valence electron. Contrary, nTiO(2) have no impact on the metal with mainly anionic species (i.e. HAsO42-). Furthermore, NOM reduced metal toxicity only for Ag and aging duration had a limited impact on the test outcome suggesting that relevant interactions between metal and nTiO(2) occur rather quick (below 24 h). These findings suggest that the charge of metals' most toxic species is the determining factor for its interaction with nanoparticles and the resulting ecotoxicological effect assessment.


Aging; nanoparticles; natural organic matter; toxic metal species; ecotoxicity

Published in

2022, volume: 16, number: 1, pages: 16-28

Authors' information

Roy, Rajdeep
University of Koblenz and Landau
Kandrapu, Vinod Kumar
University of Koblenz and Landau
Kempter, Lucas
University of Koblenz and Landau
Islam, Rezaul
University of Koblenz and Landau
Kalcikova, Gabriela
University of Ljubljana
Schulz, Ralf
University of Koblenz and Landau
Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment
University of Koblenz-Landau

UKÄ Subject classification

Environmental Sciences

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