Acute toxicity of copper oxide nanoparticles to Daphnia magna under different test conditions

作者：Thit Amalie; Huggins Krista; Selck Henriette; Baun Anders

来源：Toxicological and Environmental Chemistry, 2017, 99(4): 665-679.

DOI：10.1080/02772248.2016.1249368

• Copper oxide nanoparticles
• crustacean
• dissolved organic matter
• speciation
• toxicity

The acute toxicity of monodispersed 6nm and <100nm poly-dispersed copper oxide nanoparticles toward Daphnia magna was assessed using 48h immobilization tests. CuSO4 was used as a reference. Four different exposure conditions were tested, to study whether the toxicity of the nanoparticle suspensions changed in a way similar to what is known for dissolved Cu: first in ISO standard test conditions (pH 7.8), second with slight acidity (pH 6.5), third in the presence of citric acid, and fourth in the presence of humic acid. For all four exposure conditions, the toxicity of Cu employed in the three forms followed the same sequence, i.e., CuSO4 > monodispersed 6nm CuO >> poly-dispersed CuO. The toxicity of all Cu forms decreased from pH 6.5, >> pH 7.8, > pH 7.8 + citric acid, to >> pH 7.8 + humic acid. This pattern is in agreement with concentrations of Cu2+ calculated using the equilibrium model MINTEQ. These findings show that the acute toxicity of copper oxide nanoparticles is governed by test water composition and the chemical species Cu2+.

• 出版日期2017