With the development of nanotechnology, extensive applications of nanomaterials have caused considerable attention of their potential environmental risks to aquatic organisms. Meanwhile, some traditional environmental stressors are also increasing. The present study investigated the interactions of burgeoning nanomaterials with traditional environmental stressors on one model freshwater organism Daphnia magna, including carbon nanotubes (CNTs) with Cd, and TiO₂ nanoparticles (TiO₂-NPs) with UVB radiation. In the first study on CNTs interaction with Cd, we found that different lengths of functionalized multi-walled nanotubes (F-CNTs) both slowed down the accumulation rate of Cd in D. magna over 8 hours of exposure, and further reduced the accumulation thereafter. The LC₅₀ of D. m...[ Read more ]

With the development of nanotechnology, extensive applications of nanomaterials have caused considerable attention of their potential environmental risks to aquatic organisms. Meanwhile, some traditional environmental stressors are also increasing. The present study investigated the interactions of burgeoning nanomaterials with traditional environmental stressors on one model freshwater organism Daphnia magna, including carbon nanotubes (CNTs) with Cd, and TiO₂ nanoparticles (TiO₂-NPs) with UVB radiation. In the first study on CNTs interaction with Cd, we found that different lengths of functionalized multi-walled nanotubes (F-CNTs) both slowed down the accumulation rate of Cd in D. magna over 8 hours of exposure, and further reduced the accumulation thereafter. The LC₅₀ of D. magna in the presence of Cd and shorter CNTs was almost the same as the control group without CNTs, whereas normal CNTs significantly reduced the toxicity of Cd on D. magna. However, both types of CNTs decreased the tolerance of D. magna to Cd. In the second study on TiO₂-NPs interaction with UVB radiation, we investigated the influences of ambient and tissue TiO₂-NPs on the UVB toxicity to D. magna. We for the first time demonstrated that the mortality of D. magna decreased significantly in the presence of TiO₂-NPs both in the water and in the body, indicating that TiO₂-NPs had some protective effects on D. magna against UVB light. Although reactive oxygen species (ROS) were produced during the UVB radiation, they were not sufficient to cause D. magna mortality compared to the protective effects underlying the blockage of UVB by TiO₂-NPs. Overall, our study highlighted the potential benefit effects of nanomaterials to D. magna against environmental stresses.