In this study, we focused on investigating the plastic microfibers and how their aging due to UV irradiation could be further aggravating their negative effects on the environment. Hence, we examined the microfibers of polypropylene (PP) and polystyrene (PS) as model microplastics to observe the induced surface changes caused by aging through UV irradiation when the plastic is discarded in the environment. We also observed the enzymatic activity and microbial community changes in the soil when microplastics are added. Increases in the stretching vibrations of the –OH and C=O groups in the aged microplastic samples were observed using the attenuated total reflection Fourier-transform infrared spectroscopy analysis, confirming photo-oxidation on the microplastic surface. The soil enzyme activity was significantly reduced with the addition of virgin PP and PS, with a further reduction when adding aged PP and PS. Furthermore, the comparison of the microbial community analysis results before and after aging indicated that a slight decrease in Alphaproteobacteria and an increase in Betaproteobacteria were at the class level. Overall, the findings of this study can be used to understand the functional changes in the soil environment as a result of microplastic accumulation.

在这项研究中，我们专注于研究塑料微纤维以及它们因紫外线照射而老化如何进一步加剧它们对环境的负面影响。因此，我们检查了聚丙烯 (PP) 和聚苯乙烯 (PS) 的微纤维作为模型微塑料，以观察塑料在环境中丢弃时通过紫外线照射老化引起的表面变化。我们还观察了添加微塑料时土壤中酶活性和微生物群落的变化。使用衰减全反射傅里叶变换红外光谱分析观察到老化微塑料样品中 –OH 和 C=O 基团的伸缩振动增加，证实了微塑料表面的光氧化。添加原生PP和PS后土壤酶活性显着降低，添加陈化PP和PS时进一步降低。此外，老化前后微生物群落分析结果的比较表明，α-变形菌，并增加了β-变形菌是在类级别。总体而言，本研究的结果可用于了解微塑料积累导致土壤环境的功能变化。