Soil microbial Taxonomy and functional attributes under the combined stress of MPs and PFASs

This study investigated the effects of combined pollution by MPs (PE/PS/PVC) and PFASs (PFHxA/PFOA) on soil microbial communities via soil culture experiments. Results showed that PFASs significantly reduced bacterial Shannon diversity and evenness, with PS and PVC exerting marked inhibitory effects on bacteria while PE had a weaker impact. Fungal communities maintained high overall stability, but the PFHxA-PS combined treatment significantly decreased fungal diversity, showing a synergistic inhibitory effect. Acting as carriers, MPs in combined pollution enhanced contaminant retention and bioavailability, significantly increasing the number of differential species and simplifying community structure. Functional prediction suggested that bacterial defense mechanisms, secondary metabolite synthesis, and lipid metabolism might have been inhibited, whereas energy metabolism and post-translational protein modification may have been enhanced. Structural equation modeling (SEM) revealed that contaminants influenced microbial community assembly both directly and indirectly by altering environmental factors (pH, EC, C, N), with interactions among these factors increasing the complexity of ecological effects under combined pollution. This study provides a basis for understanding MPs-PFASs combined ecological effects and offers guidance for soil remediation and risk management.