Lei Cheng, Sun Yuqing, Tsang Daniel C W, Lin Daohui
Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
Environ Pollut. 2018 Jan;232:10-30. doi: 10.1016/j.envpol.2017.09.052. Epub 2017 Sep 28.
The increasing application of iron-based nanoparticles (NPs), especially high concentrations of zero-valent iron nanoparticles (nZVI), has raised concerns regarding their environmental behavior and potential ecological effects. In the environment, iron-based NPs undergo physical, chemical, and/or biological transformations as influenced by environmental factors such as pH, ions, dissolved oxygen, natural organic matter (NOM), and biotas. This review presents recent research advances on environmental transformations of iron-based NPs, and articulates their relationships with the observed toxicities. The type and extent of physical, chemical, and biological transformations, including aggregation, oxidation, and bio-reduction, depend on the properties of NPs and the receiving environment. Toxicities of iron-based NPs to bacteria, algae, fish, and plants are increasingly observed, which are evaluated with a particular focus on the underlying mechanisms. The toxicity of iron-based NPs is a function of their properties, tolerance of test organisms, and environmental conditions. Oxidative stress induced by reactive oxygen species is considered as the primary toxic mechanism of iron-based NPs. Factors influencing the toxicity of iron-based NPs are addressed and environmental transformations play a significant role, for example, surface oxidation or coating by NOM generally lowers the toxicity of nZVI. Research gaps and future directions are suggested with an aim to boost concerted research efforts on environmental transformations and toxicity of iron-based NPs, e.g., toxicity studies of transformed NPs in field, expansion of toxicity endpoints, and roles of laden contaminants and surface coating. This review will enhance our understanding of potential risks of iron-based NPs and proper uses of environmentally benign NPs.
铁基纳米颗粒（NPs）的应用日益广泛，尤其是高浓度的零价铁纳米颗粒（nZVI），这引发了人们对其环境行为和潜在生态影响的担忧。在环境中，铁基纳米颗粒会受到pH值、离子、溶解氧、天然有机物（NOM）和生物群等环境因素的影响而发生物理、化学和/或生物转化。本文综述了铁基纳米颗粒环境转化的最新研究进展，并阐明了它们与所观察到的毒性之间的关系。物理、化学和生物转化的类型和程度，包括聚集、氧化和生物还原，取决于纳米颗粒的性质和所处环境。越来越多的研究观察到铁基纳米颗粒对细菌、藻类、鱼类和植物的毒性，并特别关注其潜在机制进行评估。铁基纳米颗粒的毒性是其性质、受试生物耐受性和环境条件的函数。活性氧诱导的氧化应激被认为是铁基纳米颗粒的主要毒性机制。文中讨论了影响铁基纳米颗粒毒性的因素，环境转化起着重要作用，例如，表面氧化或被NOM包覆通常会降低nZVI的毒性。提出了研究空白和未来方向，旨在推动对铁基纳米颗粒环境转化和毒性的协同研究，例如，对现场转化纳米颗粒的毒性研究、毒性终点的扩展以及负载污染物和表面涂层的作用。这篇综述将增进我们对铁基纳米颗粒潜在风险的理解以及对环境友好型纳米颗粒的合理使用。
