Environmental Toxicology and Chemistry, July 2016, Vol.35(7), pp.1766-1774
To purchase or authenticate to the full-text of this article, please visit this link: http://onlinelibrary.wiley.com/doi/10.1002/etc.3325/abstract Byline: Ricki R. Rosenfeldt, Frank Seitz, Ann-Cathrin Haigis, Johanna Hoger, Jochen P. Zubrod, Ralf Schulz, Mirco Bundschuh Abstract Titanium dioxide nanoparticles (TiO.sub.2-NPs) adsorb co-occurring heavy metals in surface waters, modulating their toxicity for freshwater invertebrates. The processes triggering this interaction may be influenced by several environmental parameters; however, their relative importance remains unclear. The present study assessed the implications of aging on the joint acute toxicity of copper (Cu) and TiO.sub.2-NPs for Daphnia magna over a duration of up to 72h. The influences of aging duration as well as ionic strength, pH, and presence of different qualities of organic matter during aging were assessed. The results indicated that the presence of TiO.sub.2-NPs often reduced the Cu-induced toxicity for daphnids after aging (albeit with varying extent), which was displayed by up to 3-fold higher EC50 (50% effective concentration) values compared to the absence of TiO.sub.2-NPs. Moreover, the Cu speciation, influenced by the ionic composition and the pH as well as the presence of organic additives in the medium, strongly modulated the processes during aging, with partly limited implications of the aging duration on the ecotoxicological response of D. magna. Nonetheless, the present study underpins the potential of TiO.sub.2-NPs to modify toxicity induced by heavy metals in freshwater ecosystems under various environmental conditions. This pattern, however, needs further verification using heavy metal ions with differing properties in combination with further environmental factors, such as ultraviolet irradiation. Environ Toxicol Chem 2016;35:1766-1774. [c] 2015 SETAC Supporting information: Additional Supporting Information may be found in the online version of this article This article includes online-only Supplemental Data. CAPTION(S): Supporting Information.
Environmental Parameter ; Adsorption ; Mixture Toxicity ; Factorial Approach ; Crustacean