title: Nanosized titanium dioxide influences copper-induced toxicity during aging as a function of environmental conditions.
abstract: Titanium dioxide nanoparticles (TiO2 -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 TiO2 -NPs for Daphnia magna over a duration of up to 72 h. 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 TiO2 -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 TiO2 -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 TiO2 -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. © 2015 SETAC.
authors.affiliation: Institute for Environmental Sciences, University of Koblenz-Landau, Landau, Germany.
authors.forename: Ricki R
authors.initials: RR
authors.lastname: Rosenfeldt
authors.affiliation: Institute for Environmental Sciences, University of Koblenz-Landau, Landau, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Seitz
authors.affiliation: Institute for Environmental Sciences, University of Koblenz-Landau, Landau, Germany.
authors.forename: Ann-Cathrin
authors.initials: AC
authors.lastname: Haigis
authors.affiliation: Institute for Environmental Sciences, University of Koblenz-Landau, Landau, Germany.
authors.forename: Johanna
authors.initials: J
authors.lastname: Höger
authors.affiliation: Institute for Environmental Sciences, University of Koblenz-Landau, Landau, Germany.
authors.forename: Jochen P
authors.initials: JP
authors.lastname: Zubrod
authors.affiliation: Institute for Environmental Sciences, University of Koblenz-Landau, Landau, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Schulz
authors.affiliation: Institute for Environmental Sciences, University of Koblenz-Landau, Landau, Germany.|Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden.
authors.forename: Mirco
authors.initials: M
authors.lastname: Bundschuh
mesh_terms: D000327:Adsorption; D000375:Aging / Q000187:drug effects*; D000818:Animals; D003300:Copper / Q000737:chemistry / Q000633:toxicity*; D003621:Daphnia / Q000187:drug effects* / Q000254:growth & development; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D054750:Ecotoxicology / Q000379:methods*; D005618:Fresh Water / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D014025:Titanium / Q000737:chemistry / Q000633:toxicity*
chemical_list: C009495:titanium dioxide; D003300:Copper; D014025:Titanium
keywords: Adsorption; Crustacean; Environmental parameter; Factorial approach; Mixture toxicity