Nanotoxicology. 2016 Sep;10(7):902-12.
In this study, 25 µg/L and 250 µg/L of the food color additive titanium dioxide (TiO2) nanoparticles were added to outdoor mesocosms* placed in a lake. The control mesocosm was not treated with any TiO2.
* A mesocosm is a biological system that contains the physical features and organisms of an entire ecosystem but is smaller so it can be used in scientific experiments.
Results were dose-related, in that the biomass of Rotifera was reduced by 32% and 57% compared to the control, and soluble reactive phosphorus was reduced by 15% and 23% respectively. Other monitored biologicals, such as pytoplankton and fish, were not affected.
CONCLUSION: “environmentally relevant concentrations of TiO2 nanoparticfles may negatively affect certain parameters and taxa of the freshwater lentic aquatic ecosystem. However, these negative effects are not significant enough to affect the overall function of the ecosystem…”