Xu Liheng, Wang Yuhao, Wei Fang, Dai Zhixi, Zhang Ming
Department of Environmental Engineering, China Jiliang University, Hangzhou, 310018, China.
Department of Environmental Engineering, China Jiliang University, Hangzhou, 310018, China.
Environ Pollut. 2024 Apr 1;346:123542. doi: 10.1016/j.envpol.2024.123542. Epub 2024 Feb 12.
Microplastic (MP) pollution has become a global concern, and the transport behavior of MPs in soil-water systems is vital in determining their distribution and potential risks to the subsurface environment. To reveal the role of various soil components on MP migration, the downward transport behavior of polystyrene (PS) MPs were explored in this study via column experiments with mono or multi-soil components as porous media. Compared with the selected soil mineral volcanic rock (VR) and fine river sand (RS), condensed soil organic matter (SOM) resulted in higher transport efficiencies for PS microparticles, with greater than 90% total mass recovery under the experimental conditions. The more surface charges of SOM than minerals contribute to the high migration efficiency of PS MPs, and electrostatic repulsion is assumed a significant driving mechanism in the migration of negatively charged PS particles in soils. The ionic strength of porewater influenced the PS migration behaviors by altering the electrostatic interactions between the MPs and soil grains. The uniform mixing of SOM with mineral grains significantly enhanced the transport efficiency of PS MPs in the columns. The results provide supports for the prediction and prevention of the risks of MPs to the subsurface environment.
微塑料（MP）污染已成为全球关注的问题，微塑料在土壤-水系统中的迁移行为对于确定其分布以及对地下环境的潜在风险至关重要。为揭示各种土壤成分对微塑料迁移的作用，本研究通过以单一或多种土壤成分作为多孔介质的柱实验，探究了聚苯乙烯（PS）微塑料的向下迁移行为。与所选土壤矿物质火山岩（VR）和细河砂（RS）相比，凝聚态土壤有机质（SOM）使PS微粒具有更高的迁移效率，在实验条件下总质量回收率大于90%。SOM比矿物质具有更多的表面电荷，这有助于PS微塑料的高迁移效率，并且静电排斥被认为是带负电的PS颗粒在土壤中迁移的重要驱动机制。孔隙水的离子强度通过改变微塑料与土壤颗粒之间的静电相互作用来影响PS的迁移行为。SOM与矿物颗粒的均匀混合显著提高了柱中PS微塑料的迁移效率。研究结果为预测和预防微塑料对地下环境的风险提供了支持。
