Rethinking nano-TiO(2) safety: overview of toxic effects in humans and aquatic animals

Abstract

Titanium dioxide nanoparticles (nano-TiO2) are widely used in consumer products, raising environmental and health concerns. An overview of the toxic effects of nano-TiO(2)on human and environmental health is provided. A meta-analysis is conducted to analyze the toxicity of nano-TiO(2)to the liver, circulatory system, and DNA in humans. To assess the environmental impacts of nano-TiO2, aquatic environments that receive high nano-TiO(2)inputs are focused on, and the toxicity of nano-TiO(2)to aquatic organisms is discussed with regard to the present and predicted environmental concentrations. Genotoxicity, damage to membranes, inflammation and oxidative stress emerge as the main mechanisms of nano-TiO(2)toxicity. Furthermore, nano-TiO(2)can bind with free radicals and signal molecules, and interfere with the biochemical reactions on plasmalemma. At the higher organizational level, nano-TiO(2)toxicity is manifested as the negative effects on fitness-related organismal traits including feeding, reproduction and immunity in aquatic organisms. Bibliometric analysis reveals two major research hot spots including the molecular mechanisms of toxicity of nano-TiO(2)and the combined effects of nano-TiO(2)and other environmental factors such as light and pH. The possible measures to reduce the harmful effects of nano-TiO(2)on humans and non-target organisms has emerged as an underexplored topic requiring further investigation.