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

Abstract

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 (nTiO2) to marine zooplankton has been rarely reported. In the present study, the impacts of nTiO2 on the toxicity of phenanthrene (Phe) and cadium (Cd2+) to Artemia salina, a model marine zooplankton, were investigated. Although nTiO2 alone exerted a limited toxicity to A. salina within 48h of exposure, nTiO2 strongly altered the toxicity of Phe and Cd2+ to A. salina. Compared with the individual toxicities of pollutants to A. salina, the toxicities of Phe and Cd2+ increased by 2.0% and 12.2%, respectively, in the presence of 5mg/L nTiO2, but decreased by 24.5% and 57.1%, respectively, in the presence of 400mg/L nTiO2. These concentration-dependent impacts of nTiO2 on the toxicity of Phe or Cd2+ might be attributed to the concurrent functions of several interrelated factors including the adsorption of pollutants on nTiO2, the nTiO2-faciliated bioaccumulation of pollutants, the limited gut volume in organisms, and the aggregation and sedimentation behaviors of nTiO2. These results presented in the study could help understand the effects of manufactured nanomaterials in marine environments.