Impact of the virgin and aged polystyrene and polypropylene microfibers on the soil enzyme activity and the microbial community structure

Abstract

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. © 2021, The Author(s), under exclusive licence to Springer Nature Switzerland AG.