Microplastics (MPs) are substrates available for biofilms colonization in natural water environments. The biofilms formation may enhance the ability of MPs to adsorb harmful contaminants. Herein, we investigated the biofilms formation of three different MPs (PVC, PA and HDPE) in simulated natural environment, and observed the chemical structure, charge property, hydrophobicity and other properties of MPs affect microbial biomass and community composition. More importantly, potential pathogens were found in all three MPs biofilms. Furthermore, the adsorption capacities of original MPs and biological aging MPs for norfloxacin (NOR) was compared. HDPE has the largest adsorption capacity for NOR, while PA has the smallest adsorption capacity for NOR. It was concluded that the formation of biofilms enhanced the adsorption of NOR by 50.60%, 24.17% and 46.02% for PVC, PA and HDPE, respectively. In addition, hydrogen-bond interaction, electrostatic interaction and hydrophobic interaction were found to dominate the adsorption of NOR by MPs. Our study contributed to improve the understanding of the interactions between aging MPs and contaminants in the natural water environments, and provided essential information for ecological risk assessment of MPs.

微塑料 (MP) 是可用于在天然水环境中进行生物膜定植的基材。生物膜的形成可以增强 MPs 吸附有害污染物的能力。在此，我们研究了三种不同 MPs（PVC、PA 和 HDPE）在模拟自然环境中的生物膜形成，并观察了 MPs 的化学结构、电荷性质、疏水性等性质对微生物生物量和群落组成的影响。更重要的是，在所有三个 MPs 生物膜中都发现了潜在的病原体。此外，比较了原始 MPs 和生物老化 MPs 对诺氟沙星 (NOR) 的吸附能力。HDPE对NOR的吸附量最大，而PA对NOR的吸附量最小。得出的结论是，生物膜的形成使 NOR 的吸附增加了 50.60%，24。PVC、PA 和 HDPE 分别为 17% 和 46.02%。此外，氢键相互作用、静电相互作用和疏水相互作用被发现在 MPs 对 NOR 的吸附中占主导地位。我们的研究有助于提高对老化 MPs 与天然水环境中污染物之间相互作用的理解，并为 MPs 的生态风险评估提供必要的信息。