Xu'an research group of Hefei Institute of material science, Chinese Academy of Sciences made progress in the biological effect of nano titanium dioxide combined with heavy metals

With the wide application of titanium dioxide nanomaterials, especially in sewage treatment, it will inevitably enter the water ecosystem, and can adsorb, gather, settle and enrich to the biological phase with coexisting pollutants Recently, Xu an research group of Institute of technology and biology has made new progress in the biological effects of combined exposure of titanium dioxide nanoparticles (TiO2 NPs) and heavy metals (CD, as and Ni) based on the model of elegans elegans The related achievements have been accepted for online publication by Elsevier journal ecology and environmental safety (DOI: 10.1016 / j.ecoenv 2018.06.051) The team found that TiO2 NPs could effectively adsorb and agglomerate three heavy metals in the water environment The rapid agglomeration and deposition of TiO2 NPs changed the distribution of heavy metals in the whole water layer, resulting in the decrease of free heavy metal ions and the increase of biological exposure The toxicity evaluation of Caenorhabditis elegans to different water layers further proved that the mixture of TiO2 NPs (non-toxic concentration) and heavy metals could reduce the toxicity of the upper solution and increase the toxicity of the lower layer The accumulation level of heavy metals in nematodes showed consistent results However, the effect of TiO2 NPs on as (III) is not as obvious as that on CD and Ni, which may be related to the special valence state of as (III) in water environment To sum up, the settling behavior of TiO2 NPs in water environment changed the toxicity and bioaccumulation level of heavy metals to elegans elegans, and the agglomeration size of particles and ionic strength of solution were important factors affecting the settling effect This study provides new evidence for the joint exposure toxicity of TiO2 NPs and environmental pollutants, and also shows that the interaction and common fate of TiO2 NPs and heavy metals need to be an important part of ecological risk assessment The research is supported by national major research plan 973, leading project B of Chinese Academy of Sciences, National Natural Science Foundation of China and other topics.