Microplastics abundance associated with farmland use types and the impact on soil microbial communities: A case study in Southern China

To investigate the impact of various farmland use types on the spatial distribution of microplastics (MPs) and their correlation with microbial communities, 78 soil samples from distinct farmland use types (orchard, paddy field, and vegetable field) in Southern China were examined. Results revealed that the abundance of MPs ranged from 528 to 39,864 items/kg with a mean abundance of 10,562 items/kg, which were primarily 0-30 µm in size. A total of 32 polymer types were identified, with the main polymer being polyethylene terephthalate (PET, 28.8 %), followed by polyvinyl chloride (PVC, 13.5 %) and fluororubber (FKM, 9.5 %). The abundance of MPs was highest in orchard field (8896 ± 5745 items/kg), followed by paddy field (4176 ± 2976 items/kg) and lastly vegetable field (2967 ± 3698 items/kg). Results of 16 S rRNA gene amplicon sequencing showed that the presence of MPs affected the bacterial distribution patterns. Compared with soil bacterial communities, the spatial dispersion and dissimilarity of plasticsphere communities were less variable. Notably, the predicted sequences related to xenobiotics biodegradation and metabolism became more abundant, thereby affecting the ecological function of soil. Overall, this study provides important data for further research on MP ecosystem risks associated with farmland use types.