Feng Simin, Yao Runfang, Chen Yuyun, Zhang Hongli
School of Water and Environment, Chang'an University, Middle South Second Ring Road, Xi'an, 710061, Shaanxi Province, China.
Key Laboratory of Subsurface Hydrology and Ecological Effect in Arid Region of the Ministry of Education, Chang'an University, Xi'an, China.
Environ Geochem Health. 2025 Jun 18;47(7):275. doi: 10.1007/s10653-025-02584-9.
Microplastics (MPs) in ecosystems have garnered attention, yet their effects on the environmental behavior of organic pollutants in river sediments remain poorly understood. This study investigated how polyethylene (PE) and polyvinyl chloride (PVC) MPs influence the adsorption and migration of Phenanthrene (Phe) in sediments via batch and column experiments. Results revealed that sediment adsorption capacity for Phe followed: sediment containing 2% PE (120.27 μg g) > sediment without MPs (111.93 μg g) > sediment containing 2% PVC (104.79 μg g), attributed to PE's looser, more elastic structure with larger free volume compared to glassy PVC. Humic acid (HA) inhibited Phe adsorption by occupying sites and solubilizing all sediments. pH effects showed a non-linear trend due to MPs' zero-charge points, with adsorption increasing and decreasing as pH rose. Migration was influenced by Phe's initial concentration, MP type/proportion, and HA levels: higher initial Phe increased maximum penetration rate from 0.36 to 0.44, enhancing mobility, while migration ability ranked: sediment without MPs > sediment containing PE > sediment containing PVC. These findings highlight that PE increased phenanthrene adsorption by 26% compared to PVC, enhancing pollutant retention in sediments and posing risks to downstream ecosystems. Our study provides critical insights into the role of polymer properties and environmental factors in regulating contaminant behavior, advancing the understanding of MPs as vectors for hydrophobic organic pollutants in aquatic environments, and bridging the knowledge gap between microplastic interactions and organic pollutant behavior in river sediments.
生态系统中的微塑料（MPs）已引起关注，但其对河流沉积物中有机污染物环境行为的影响仍知之甚少。本研究通过批量实验和柱实验，研究了聚乙烯（PE）和聚氯乙烯（PVC）微塑料如何影响沉积物中菲（Phe）的吸附和迁移。结果表明，沉积物对菲的吸附能力顺序为：含2% PE的沉积物（120.27 μg g）＞不含微塑料的沉积物（111.93 μg g）＞含2% PVC的沉积物（104.79 μg g），这归因于与玻璃态PVC相比，PE结构更松散、更具弹性且自由体积更大。腐殖酸（HA）通过占据位点和溶解所有沉积物来抑制菲的吸附。由于微塑料的零电荷点，pH效应呈现非线性趋势，随着pH升高，吸附先增加后减少。迁移受菲的初始浓度、微塑料类型/比例和HA水平的影响：较高的菲初始浓度使最大穿透率从0.36提高到0.44，增强了迁移性，而迁移能力顺序为：不含微塑料的沉积物＞含PE的沉积物＞含PVC的沉积物。这些发现突出表明，与PVC相比，PE使菲的吸附增加了26%，增强了污染物在沉积物中的滞留，并对下游生态系统构成风险。我们的研究为聚合物性质和环境因素在调节污染物行为中的作用提供了关键见解，推进了对微塑料作为水生环境中疏水性有机污染物载体的理解，并弥合了河流沉积物中微塑料相互作用与有机污染物行为之间的知识差距。
