[Accumulation and Biotransformation in Typical Freshwater Algae Species Influenced by Titanium Dioxide Nanoparticles Under Long-term Exposure].

: In the present study, the accumulation and biotransformation of arsenate in typical freshwater algae species were examined under long-term influence of titanium dioxide nanoparticles (nano-TiO2). Results showed that different algae species had largely varied capacities of accumulation and biotransformation of arsenate. The arsenic accumulation reached (819.66±11.25) μg·g-1 DW in Scenedesmus obliquus, which was higher than that in Microcystis aeruginosa of (355.95±8.31) μg·g-1 DW. Nano-TiO2 increased arsenic accumulation in these exposed algae species, and then reduced arsenic levels in the relative culture media. Furthermore, nano-TiO2 improved arsenic biotransformation in the exposed algae, and the organic arsenic was dimethylarsinous acid (DMA) and monomethylarsonous acid (MMA) in Microcystis aeruginosa and Scenedesmus obliquus, respectively. Additionally, the release of organic arsenic was lower from the exposed algae in nano-TiO2 treatments than in the control, indicating that nano-TiO2 couldn't stimulate the release of organic arsenic from algae under long-term exposure. These results could improve insights on the ecological risk of nano-TiO2 associated with arsenic in the environment.