Aging reconfigures physicochemical inhibition mechanisms of polyamide microplastics on antibiotic transport in saturated soils: Micro-CT based pore characterization coupled with transport modeling

IF 7.3 2区环境科学与生态学 Q1 ENVIRONMENTAL SCIENCES

Environmental Pollution Pub Date : 2025-08-06 DOI:10.1016/j.envpol.2025.126957

Zehua Xu, Yonghui Tu, Liming Dai, Jia Li

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Abstract

Microplastics (MPs) and antibiotics coexist ubiquitously in terrestrial system, yet the mechanistic interplay between MP aging and antibiotic transport remains poorly understood. In this study, the effects of pristine polyamide MPs (PPA-MPs) and aged polyamide MPs (APA-MPs) on trimethoprim (TMP) mobility were investigated through coupled saturated soil column experiments, computed tomography scanning, and mechanistic modeling. Results demonstrate concentration-dependent TMP transport inhibition by both types of MPs, with APA-MPs exhibiting greater inhibitory effect than PPA-MPs at equivalent concentrations. Notably, the two types of MPs elicit distinct influencing mechanisms. The PPA-MPs mitigated TMP adsorption by inducing a dilution effect and enhancing electrostatic repulsion; however, they paradoxically hindered TMP mobility by causing pore occlusion. Aging shifted MP effects from physical blockage to adsorption-occlusion synergy via the following pathways: (i) particle size reduction exacerbates pore clogging and (ii) increased surface roughness and oxygen functionality enhance TMP adsorption. The >10-fold variation in breakthrough times and order-of-magnitude changes in adsorption coefficients under pH modulation far exceeded impacts from flow velocity or ionic strength. These findings reveal the aging-induced transition from physical blockage induced by PPA-MPs to adsorption-hydraulic synergy driven by APA-MPs, providing critical insights for predicting antibiotic fate in MP-contaminated saturated soils under dynamic environmental conditions.

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老化重新配置聚酰胺微塑料对饱和土壤中抗生素运输的物理化学抑制机制：基于Micro-CT的孔隙表征与运输建模

微塑料和抗生素在陆地系统中普遍存在，但微塑料老化与抗生素转运之间的机制相互作用尚不清楚。本研究通过耦合饱和土柱实验、计算机断层扫描和机理建模，研究了原始聚酰胺MPs （PPA-MPs）和老化聚酰胺MPs （APA-MPs）对甲氧苄啶（TMP）迁移性的影响。结果表明，两种MPs对TMP转运的抑制作用与浓度有关，在相同浓度下，APA-MPs比PPA-MPs表现出更大的抑制作用。值得注意的是，这两种类型的MPs产生了不同的影响机制。PPA-MPs通过诱导稀释效应和增强静电斥力来减轻TMP的吸附；然而，矛盾的是，它们通过引起孔隙堵塞来阻碍TMP的迁移。老化通过以下途径将MP效应从物理阻塞转变为吸附-闭塞协同作用：(i)粒径减小加剧了孔隙堵塞；（ii）表面粗糙度和氧功能的增加增强了TMP的吸附。在pH调制下，突破时间的10倍变化和吸附系数的数量级变化远远超过了流速或离子强度的影响。这些发现揭示了衰老诱导的从PPA-MPs诱导的物理阻塞到APA-MPs驱动的吸附-水力协同作用的转变，为预测动态环境条件下mp污染饱和土壤中的抗生素命运提供了重要见解。

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来源期刊

Environmental Pollution 环境科学-环境科学

CiteScore

16.00

自引率

6.70%

发文量

2082

审稿时长

2.9 months

期刊介绍： Environmental Pollution is an international peer-reviewed journal that publishes high-quality research papers and review articles covering all aspects of environmental pollution and its impacts on ecosystems and human health. Subject areas include, but are not limited to: • Sources and occurrences of pollutants that are clearly defined and measured in environmental compartments, food and food-related items, and human bodies; • Interlinks between contaminant exposure and biological, ecological, and human health effects, including those of climate change; • Contaminants of emerging concerns (including but not limited to antibiotic resistant microorganisms or genes, microplastics/nanoplastics, electronic wastes, light, and noise) and/or their biological, ecological, or human health effects; • Laboratory and field studies on the remediation/mitigation of environmental pollution via new techniques and with clear links to biological, ecological, or human health effects; • Modeling of pollution processes, patterns, or trends that is of clear environmental and/or human health interest; • New techniques that measure and examine environmental occurrences, transport, behavior, and effects of pollutants within the environment or the laboratory, provided that they can be clearly used to address problems within regional or global environmental compartments.