TiO2 nanoparticles in the marine environment: Impact on the toxicity of phenanthrene and Cd2 + to marine zooplankton Artemia salina

The impact of manufactured nanoparticles on the toxicity of co-existing pollutants in aquatic environments has raised increasing concerns. However, the toxicity of polycyclic aromatic hydrocarbons or metal ions in the presence of titanium dioxide nanoparticles (nTiO 2 ) to marine zooplankton has been rarely reported. In the present study, the impacts of nTiO 2 on the toxicity of phenanthrene (Phe) and cadium (Cd 2   + ) to Artemia salina , a model marine zooplankton, were investigated. Although nTiO 2 alone exerted a limited toxicity to A. salina within 48   h of exposure, nTiO 2 strongly altered the toxicity of Phe and Cd 2   + to A. salina . Compared with the individual toxicities of pollutants to A. salina , the toxicities of Phe and Cd 2   + increased by 2.0% and 12.2%, respectively, in the presence of 5   mg/L nTiO 2, but decreased by 24.5% and 57.1%, respectively, in the presence of 400   mg/L nTiO 2 . These concentration-dependent impacts of nTiO 2 on the toxicity of Phe or Cd 2   + might be attributed to the concurrent functions of several interrelated factors including the adsorption of pollutants on nTiO 2 , the nTiO 2 -faciliated bioaccumulation of pollutants, the limited gut volume in organisms, and the aggregation and sedimentation behaviors of nTiO 2 . These results presented in the study could help understand the effects of manufactured nanomaterials in marine environments.