Toxic effects of different types of zinc oxide nanoparticles on algae, plants, invertebrates, vertebrates and microorganisms

Concerns about the potential environmental risks of zinc oxide nanoparticles (ZnO NPs) are becoming an important issue because of their rapid growth in different fields. ZnO NPs are inevitably released in the environment during the production, transport, use and disposal process. Therefore, it is necessary to understand their toxicities and mode of actions. This review summarizes the toxic effects of ZnO NPs with different properties and exposed conditions on different species. The mechanisms of ZnO NPs on living organisms could be mainly attributed to one or more of the following aspects: the physical damage of direct contact, the dissolved zinc ions and the ROS-mediated mechanism. This paper systematically reviews the toxic effects of ZnO NPs on organisms and puts forward the existing problems, which are helpful for the safe and efficient use of ZnO NPs, providing the basis for further study of the toxic effects of ZnO NPs and establishing a comprehensive and safe evaluation system.