Objective The study was conducted to explore the effects of microplastics and polycyclic aromatic hydrocarbons(PAHs) on microbial community structure, biological functions and metabolic pathways in agricultural soil so as to provide a theoretical basis for ecological risk assessment and remediation of combined microplastics-PAHs pollution.

Method Polyvinyl chloride(PVC) and pyrene(PY) were selected as the representatives of microplastics and PAHs, respectively. The responses of abundance, composition and function of microbial communities in agricultural soil to the combined pollution of PVC-PY were studied by using metagenomic techniques and PICRUSt function prediction.

Result Modifications of soil microbial community structure were found with the addition of PVC and PY. The relative abundance of Acidobacteria, Betaproteobacteria, Gemmatimonas, Nitrososphaera and Burkholderia were decreased in the presence of PVC-PY. Addition of PVC-PY improved the relative abundance of Sphingomonas, Nocardioides, Lysobacter, Marmoricola, Streptomyces, Mycobacterium, Sphingopyxis, Sphingobium, Novosphingobium and Luteimonas. According to the analysis of GO function, KEGG metabolic pathway and CAZy enzyme function, PVC-PY showed positive effects on the development, reproduction and self-regulation of soil microorganisms, and then accelerated the metabolic process of bacteria flora and the transport/excretion process of harmful products.

Conclusion The addition of PVC-PY induced the changes in the structure and function of soil microbial communities, which increased their antioxidant capacity. Thus, the soil microbes had better adaptability to polluted environment.