Aquatic toxicology, 2013, Vol.126, pp.163-168
The increasing use of titanium dioxide nanoparticles (nTiO₂) inevitably results in their release into the environment, raising concerns about potential adverse effects in wildlife. By following standard test protocols, several studies investigated the ecotoxicity of nTiO₂ among others to Daphnia magna. These studies indicated a large variability – several orders of magnitude – in the response variables. However, other factors, like nanoparticle characteristics and test design, potentially triggering these differences, were largely ignored. Therefore, the present study assessed the chronic ecotoxicity of two nTiO₂ products with varying crystalline structure (A-100; P25) to D. magna. A semi-static and a flow-through exposure scenario were compared, ensuring that both contained environmentally relevant concentrations of dissolved organic carbon. Utilizing the semi-static test design, a concentration as low as 0.06mg/L A-100 (∼330nm) significantly reduced the reproduction of daphnia indicating environmental risk. In contrast, no implication in the number of released offspring was observed during the flow-through experiment with A-100 (∼140nm). Likewise, P25 (∼130nm) did not adversely affect reproduction irrespective of the test design utilized. Given the present study's results, the particle size, the product composition, i.e. the crystalline structure, and the accumulation of nTiO₂ at the bottom of the test vessel – the latter is relevant for a semi-static test design – may be suggested as factors potentially triggering differences in nTiO₂ toxicity to D. magna. Hence, these factors should be considered to improve environmental risk assessment of nanoparticles. ; p. 163-168.
Particle Size ; Progeny ; Titanium Dioxide ; Dissolved Organic Carbon ; Exposure Scenario ; Wildlife ; Crystal Structure ; Reproduction ; Daphnia Magna ; Risk ; Ecotoxicology ; Toxicity ; Adverse Effects ; Nanoparticles
AGRIS (Food and Agriculture Organization of the United Nations)
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