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

Amalie Thit Jensen, Krista Huggins, Henriette Selck, Anders Baun

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

The acute toxicity of monodispersed 6 nm and <100 nm poly-dispersed copper oxide nanoparticles toward Daphnia magna was assessed using 48 h 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 6 nm 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+.
Original languageEnglish
JournalToxicological and Environmental Chemistry
Volume99
Issue number4
Pages (from-to)665-679
ISSN0277-2248
DOIs
Publication statusPublished - 2017

Keywords

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

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