Sources, pollution, and ecological impacts of soil microplastics-A review

Soil is widely recognized as the primary environmental source and sink for microplastics within terrestrial ecosystems, with soil microplastics contamination attracting an increasing attention. The rapid growth in relevant literature underscores the rising research interest in this field. This review systematically summarizes the direct and indirect sources of microplastics in soil, focusing on their two primary migration pathways: horizontal and vertical migration pathway. The global distribution characteristics of microplastics across different land use types and in deep soil layers is examined, revealing the dual role as both independent pollutants and carriers of other pollutants. The ecological impacts of microplastics aging and degradation processes are critically assessed from the perspectives of soil fauna, flora, and microbial communities. Finally, the current lack of effective source tracing methods and limitations in existing ecological risk assessment are acknowledged, and future research directions are presented to advance mechanisms understanding and risk evaluation. This work provides a comprehensive foundation for understanding the ecological impacts of soil microplastics and supports the development of soil environmental protection strategies.