The effect of polyvinyl chloride microplastics on soil properties, greenhouse gas emission, and element cycling-related genes: Roles of soil bacterial communities and correlation analysis.

Different shapes (membranes and particles) and concentrations (1 % (w/w) and 2 % (w/w)) of polyvinyl chloride (PVC) microplastics (MPs) were investigated to determine their impact on the soil environment. The incorporation of MPs can disrupt soil macroaggregates. Compared with 1 % (w/w) MPs, 2 % MPs resulted in a significant increase in soil organic carbon content. MP particles significantly increased soil CO emissions, and CH emissions were enhanced by both membrane and particle MPs at high concentrations. Microplastics can alter the abundance of Actinobacteria, Proteobacteria, Chloroflexi, Acidobacteriota, and Firmicutes at the phylum level, and Nocardioides, Rhodococcus and Bacillus at the genus level. MP particles had a more significant impact on soil bacterial communities than MP membranes. The relative abundances of genes involved in the C, N, and P cycles were detected by qPCR, and more remarkable changes were observed in MP membrane treatments. The relative abundance of Vicinamibacteraceae and Vicinamibacterales exhibited a positive correlation with most C/N/P cycle-related genes, whereas Pseudarthrobacter and Nocardioides demonstrated a negative correlation. This study highlights that the influence of MPs on soil parameters is mediated by soil microorganisms, providing insight into the effects of MPs on the soil microenvironment.