Recently, biodegradable plastics (BPs) as an alternative of conventional plastics have been widely advocated and applied. However, there is still a large research gap between the formation of secondary microplastics (MPs) and colonized microorganisms on their surface under long-term aging in different environments. In this study, the generation of secondary MPs and the formation of surface biofilms on the micro-sized (3-5 mm) biodegradable plastic poly (butyleneadipate-co-terephthalate) (BP-PBAT) and conventional plastic polyvinyl chloride (CP-PVC) under long-term UV aging was investigated. The results showed that hundreds and even thousands of MPs (185.53 ± 85.73 items/g - 1473.27 ± 143.67 items/g) were generated by BP-PBAT and CP-PVC after aged for 90 days, and the abundance of MPs produced by BP-PBAT was significantly higher than that of CP-PVC. Moreover, the α diversities and detected OTU number of biofilm communities formed on MPs increased with MPs-aging. The genes related to the formation of biofilms was significantly expressed on aged MPs and the genes related to human pathogens and diseases were also detected in enriching on MPs surface. Overall, BPs may lead to greater ecological risks as it releases thousands of secondary MPs after being aged, and their environmental behavior needs to be further explored.

近年来，可生物降解塑料（BPs）作为传统塑料的替代品得到了广泛的提倡和应用。然而，在不同环境下长期老化下，次生微塑料（MPs）的形成及其表面定植微生物之间仍存在较大的研究差距。在这项研究中，次级 MPs 的产生和表面生物膜的形成在微米级 (3-5 mm) 可生物降解塑料聚（己二酸-共对苯二甲酸丁二醇酯）（BP-PBAT）和常规塑料聚氯乙烯（CP-PVC）在长期紫外线老化下进行了研究。结果表明，BP-PBAT和CP-PVC在老化90天后产生了数百甚至数千个MPs（185.53 ± 85.73 items/g - 1473.27 ± 143.67 items/g），BP- PBAT明显高于CP-PVC。此外，随着 MPs 老化，在 MPs 上形成的生物膜群落的 α 多样性和检测到的 OTU 数量增加。与生物膜形成相关的基因在老年MPs上显着表达，与人类病原体和疾病相关的基因也在MPs表面富集。总体而言，BPs 可能会导致更大的生态风险，因为它会在老化后释放数千个二级 MP，