Effects of TiO 2 nanoparticles on the life‐table parameters, antioxidant indices, and swimming speed of the freshwater rotifer Brachionus calyciflorus

Titanium dioxide nanoparticles (nTiO 2 ) have raised environmental concerns and display potential hazards to aquatic organisms and even humans. However, only a few reports tested the toxicity of nTiO 2 to rotifers. In the present study, acute and chronic toxicity of nTiO 2 to the freshwater rotifer Brachionus calyciflorus was investigated at different temperatures. At 25°C, the 24 and 48‐hr LC 50 was 117.14 and 60.11 mg/L, respectively. At 15°C, 20°C, 25°C, and 30°C, exposure to nTiO 2 significantly decreased life expectancy at birth, net reproductive rate, generation time, average lifespan, and/or intrinsic rate of population increase of B. calyciflorus ( p  < .05). High temperature enhanced the toxicity of nTiO 2 to rotifers. The swimming linear speed of rotifers significantly increased ( p  < .05) in treatments with 200 µg/L nTiO 2 , compared with the control. In addition, treatments with 8 µg/L to 5 mg/L nTiO 2 significantly increased superoxide dismutase activity ( p  < .05). Glutathione content and catalase activity increased significantly after exposure to 8 µg/L nTiO 2  but decreased significantly in treatments with nTiO 2 concentrations ranging from 40 µg/L to 5 mg/L ( p  < .05). There were no significant changes in malondialdehyde contents among nTiO 2 treatments and control. Overall, the present study indicated that nTiO 2 revealed high toxicity to rotifers, displaying high environmental risks to aquatic ecosystems.