Engineered nanomaterials (NMs) are increasingly released into the environment with the rapid development of nanotechnology. In this review, we present the current understanding on the safety of NMs in the environment from the existing literature. For the four typical NMs selected (i.e., TiO₂, Ag, CuO, graphene), available data on both environmental concentrations and ecotoxicity (e.g., predicted no effect concentrations [PNECs]) were collected from the published literature. All the four typical NMs did not pose a high risk by comparing environmental concentrations and PNECs. Toxicity of NMs as affected by environmental factors was further discussed. It can be concluded that nanotoxicity could be further lowered under environmental conditions for most scenarios. Generally, the environmental risk of NMs is of low concern currently, while the risk in specific scenarios such as surface water and soil near the point sources (e.g., wastewater effluent, sewage sludge) should be paid more attention. Moreover, the NM-induced toxicity could be changed by various environmental factors such as sunlight irradiation, natural organic matter, and mineral particles. In view of the uncertainties on environmental concentrations and ecotoxicity, the challenges on comprehensive understanding on the environmental risks of NMs, and the future research perspectives were addressed and presented.

随着纳米技术的迅速发展，工程纳米材料（NMs）越来越多地释放到环境中。在这篇综述中，我们根据现有文献介绍了目前对环境中NMs安全性的理解。对于所选的四个典型NM（即TiO ₂（Ag，CuO，石墨烯），环境浓度和生态毒性的可用数据（例如，预测的无作用浓度[PNECs]）均从已发表的文献中收集。通过比较环境浓度和PNEC，所有四个典型的NM都不构成高风险。进一步讨论了受环境因素影响的NMs的毒性。可以得出结论，对于大多数情况，在环境条件下纳米毒性可以进一步降低。通常，目前对NMs的环境风险关注不大，而在特定情况下（如点源附近的地表水和土壤）（如废水，污泥）的风险应引起更多关注。此外，NM诱导的毒性可能会受到各种环境因素的影响，例如阳光照射，天然有机物，和矿物颗粒。鉴于环境浓度和生态毒性的不确定性，提出并提出了对NMs的环境风险的全面理解所面临的挑战以及未来的研究前景。