Program of the Environment and Sustainability, Department of Environmental and Occupational Health, Texas A&M University, College Station, TX, 77843, USA.
Zachery Department of Civil and Environmental Engineering, Texas A&M University, College Station, TX, 77843, USA.
Chemosphere. 2021 May;271:129597. doi: 10.1016/j.chemosphere.2021.129597. Epub 2021 Jan 8.
The release of plastics in nature is an increasing global concern due to their degradation from microplastics (MPs) and even to nanoplastics (NPs), which are being recognized as a potential global threat to humans and environment. This paper summarizes the current knowledge on the effect of different environmental factors on the aggregation of MPs and NPs in aquatic environment. Stability (or extent of aggregation) of MPs and NPs varies with pH, ionic strength, ion type (monovalent, divalent, and trivalent), kind of minerals, and natural organic matter (NOM) of the aquatic environment. Electrostatic interactions between particles at different pH and ionic strength caused by salts of different valents govern the aggregation. In the presence of minerals (or inorganic colloids), net surface charge of mineral and surface potential of MPs and NPs (i.e., positive or negative surface functionality) play important roles in the heteroaggregation of MPs and NPs. In the presence of NOM, additional complex interactions including hydrophobic interactions and bridging are also involved in the aggregation of particles. Understanding the interactions of MPs and NPs of different surface charge with diverse environmental factors at a wide range of environmental conditions is pivotal to assess the mobility and the fate of degraded plastic particles and their risk to human health and ecological systems.
由于微塑料（MPs）甚至纳米塑料（NPs）的降解，塑料在自然界中的释放正成为一个日益严重的全球性问题，人们开始认识到它们可能对人类和环境构成全球性威胁。本文总结了目前关于不同环境因素对水环境污染中 MPs 和 NPs 聚集的影响的相关知识。 MPs 和 NPs 的稳定性（或聚集程度）随 pH 值、离子强度、离子类型（单价、二价和三价）、矿物质种类和水相中的天然有机物（NOM）而变化。不同价态盐引起的不同 pH 值和离子强度下颗粒间的静电相互作用决定了聚集。在矿物质（或无机胶体）存在的情况下，矿物质的净表面电荷和 MPs 和 NPs 的表面电势（即正或负的表面功能）在 MPs 和 NPs 的异质聚集中起着重要作用。在 NOM 存在的情况下，还涉及包括疏水相互作用和桥接在内的其他复杂相互作用。了解不同表面电荷的 MPs 和 NPs 与广泛环境条件下各种环境因素的相互作用，对于评估降解塑料颗粒的迁移性和归宿及其对人类健康和生态系统的风险至关重要。
