Spatial heterogeneity of EPS-mediated microplastic aggregation in phycosphere shapes polymer-specific Trojan horse effects

IF 11.4 1区环境科学与生态学 Q1 ENGINEERING, ENVIRONMENTAL

Water Research Pub Date : 2025-04-20 DOI:10.1016/j.watres.2025.123686

Xuan Fan , Chen Wang , Lingyu Kong , Jingyi Wang , Yixiao Tan , Zhuodong Yu , Xiangyang Xu , Liang Zhu

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Abstract

The pervasive contamination of aquatic ecosystems by microplastics represented a critical environmental challenge. While algal-bacterial symbiosis systems demonstrated potential for microplastic aggregation via extracellular polymeric substances (EPS), prior studies have focused on temporal dynamics rather than spatial heterogeneity in phycosphere. This study systematically investigated the adsorption mechanisms of Polyvinyl chloride (PVC), polyethylene terephthalate (PET), polyethylene (PE) and polystyrene (PS) across stratified EPS fractions, tightly bound (TB-EPS), loosely bound (LB-EPS), and soluble (S-EPS), in phycosphere. Combining controlled aggregation assays with multimodal characterization, we revealed a hierarchical spatial framework governing EPS-microplastic interactions. Adsorption efficiency governed by polymer-specific interfacial energies and EPS organic composition. EPS at distinct hierarchical levels exhibited material-specific adsorption preferences for microplastics. PVC and PET demonstrated higher affinities for hydrocarbon components, while PE and PS were preferentially captured through interactions with polysaccharides and amide I groups, respectively. The adsorption and aggregation behaviors between EPS and microplastics in the phycosphere promoted eco-corona formation and induced the Trojan horse effect. However, the energy barrier of interaction forces and EPS spatial configurations jointly governed the hierarchical stabilization of polymer-specific microplastics. PVC and PET primarily colonized the outermost S-EPS layer, PS preferentially accumulated in the intermediate LB-EPS layer, and PE penetrated into the innermost TB-EPS layer. These findings addressed a key knowledge gap by delineating the ecological niche-specific distribution of EPS-microplastic binding, offering novel insights for optimizing bioremediation strategies and informing regulatory measures targeting particulate plastic pollution in hydrologic systems.

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eps介导的微塑料聚集在藻球中形成聚合物特异性特洛伊木马效应的空间异质性

微塑料对水生生态系统的普遍污染是一项严峻的环境挑战。虽然藻类-细菌共生系统通过胞外高分子物质（EPS）展示了微塑料聚集的潜力，但之前的研究主要集中在时间动态上，而不是植物圈的空间异质性上。本研究系统地研究了聚氯乙烯（PVC）、聚对苯二甲酸乙二酯（PET）、聚乙烯（PE）和聚苯乙烯（PS）在植物体中的分层 EPS（紧密结合型（TB-EPS）、松散结合型（LB-EPS）和可溶性（S-EPS））吸附机制。通过将受控聚集试验与多模式表征相结合，我们揭示了支配 EPS 与微塑料相互作用的分层空间框架。吸附效率受聚合物特定界面能和 EPS 有机成分的制约。不同层次的发泡聚苯乙烯对微塑料表现出特定材料的吸附偏好。聚氯乙烯（PVC）和聚对苯二甲酸乙二酯（PET）对碳氢化合物成分具有更高的亲和力，而聚乙烯（PE）和聚苯硫醚（PS）则分别通过与多糖和酰胺I基团的相互作用而被优先捕获。EPS 和微塑料在植物圈中的吸附和聚集行为促进了生态电晕的形成，并引发了特洛伊木马效应。然而，相互作用力的能量障碍和EPS的空间构型共同制约了聚合物特异性微塑料的分层稳定。聚氯乙烯（PVC）和聚对苯二甲酸乙二醇酯（PET）主要定殖在最外层的S-EPS层，聚苯硫醚（PS）优先在中间层的LB-EPS层积聚，而聚乙烯（PE）则渗透到最内层的TB-EPS层。这些发现填补了一个关键的知识空白，划定了 EPS 与微塑料结合的生态位特异性分布，为优化生物修复策略提供了新的见解，并为针对水文系统中微粒塑料污染的监管措施提供了信息。

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来源期刊

Water Research 环境科学-工程：环境

CiteScore

20.80

自引率

9.40%

发文量

1307

审稿时长

38 days

期刊介绍： Water Research, along with its open access companion journal Water Research X, serves as a platform for publishing original research papers covering various aspects of the science and technology related to the anthropogenic water cycle, water quality, and its management worldwide. The audience targeted by the journal comprises biologists, chemical engineers, chemists, civil engineers, environmental engineers, limnologists, and microbiologists. The scope of the journal include: •Treatment processes for water and wastewaters (municipal, agricultural, industrial, and on-site treatment), including resource recovery and residuals management; •Urban hydrology including sewer systems, stormwater management, and green infrastructure; •Drinking water treatment and distribution; •Potable and non-potable water reuse; •Sanitation, public health, and risk assessment; •Anaerobic digestion, solid and hazardous waste management, including source characterization and the effects and control of leachates and gaseous emissions; •Contaminants (chemical, microbial, anthropogenic particles such as nanoparticles or microplastics) and related water quality sensing, monitoring, fate, and assessment; •Anthropogenic impacts on inland, tidal, coastal and urban waters, focusing on surface and ground waters, and point and non-point sources of pollution; •Environmental restoration, linked to surface water, groundwater and groundwater remediation; •Analysis of the interfaces between sediments and water, and between water and atmosphere, focusing specifically on anthropogenic impacts; •Mathematical modelling, systems analysis, machine learning, and beneficial use of big data related to the anthropogenic water cycle; •Socio-economic, policy, and regulations studies.