Effects of environmental factors on the growth and microcystin production of Microcystis aeruginosa under TiO2 nanoparticles stress.Sci Total Environ. 2020 Sep 10; 734:139443.ST
Due to the growing use and release of nanomaterials, their toxic impacts on aquatic ecosystems have drawn widespread attention in recent years. In this study, we exposed Microcystis aeruginosa to 5 mg/L titanium dioxide nanoparticles (nTiO2) under different culture conditions (pH 6, 7, 8, 9; 20 °C, 25 °C, 30 °C). The results showed that algae had the worst growth status with lowest biomass, lowest photosynthetic activity and highest reactive oxygen species (ROS) generation under 5 mg/L nTiO2 at pH 6 and 20 °C. Images by scanning electron microscopy (SEM) revealed that nTiO2 hindered light absorption by algal cells by wrapping the algal surface, which led to obvious cell surface deformation at pH 6 or 20 °C. In addition, microcystin-LR (MC-LR) production increased as temperature or pH decreased when exposed to nTiO2 at 5 mg/L, demonstrating that falling pH or temperature enhanced the adverse effects toward algal cells under nTiO2 stress and the potential risk of algae to the environment.