Ecotoxicology and Environmental Safety, Jan, 2015, Vol.111, p.263(8)
To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ecoenv.2014.09.031 Byline: Frank Seitz, Ricki R. Rosenfeldt, Katharina Storm, George Metreveli, Gabriele E. Schaumann, Ralf Schulz, Mirco Bundschuh Abstract: Studies assessing the acute and chronic toxicity of silver nanoparticle (nAg) materials rarely consider potential implications of environmental variables. In order to increase our understanding in this respect, we investigated the acute and chronic effects of various nAg materials on Daphnia magna. Thereby, different nanoparticle size classes with a citrate coating (20-, ~30-, 60- as well as 100-nm nAg) and one size class without any coating (140nm) were tested, considering at the same time two pH levels (6.5 and 8.0) as well as the absence or presence of dissolved organic matter (DOM; 〈0.1 or 8.0mg total organic carbon/L). Results display a reduced toxicity of nAg in media with higher pH and the presence of DOM as well as increasing initial particle size, if similarly coated. This suggests that the associated fraction of Ag species 〈2nm (including Ag.sup.+) is driving the nAg toxicity. This hypothesis is supported by normalizing the 48-h EC.sub.50-values to Ag species 〈2nm, which displays comparable toxicity estimates for the majority of the nAg materials assessed. It may therefore be concluded that a combination of both the particle characteristics, i.e. its initial size and surface coating, and environmental factors trigger the toxicity of ion-releasing nanoparticles. Author Affiliation: (a) Institute for Environmental Sciences, Group of Ecotoxicology & Environment, University of Koblenz-Landau, Fortstrasse 7, 76829 Landau, Germany (b) Institute for Environmental Sciences, Group of Environmental and Soil Chemistry, University of Koblenz-Landau, Fortstrasse 7, 76829 Landau, Germany (c) Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Lennart Hjelms Vag 9, 75007 Uppsala, Sweden Article History: Received 10 July 2014; Revised 26 September 2014; Accepted 30 September 2014
Ph -- Analysis ; Toxicity -- Analysis ; Soil Chemistry -- Analysis
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