Microplastics in soil: a review on research status, sources, methods, and remediation strategies

Microplastics (MPs) are persistent pollutant distributes in sea, soil, and atmosphere widely. Nowadays, there has been an increasing awareness of negative impact of MPs on the environment, especially focusing on extensive research in the aquatic environment. However, there is still a significant research gap in the study of MPs in soil, despite the serious harm to soil.

This review conducts literature analysis by Citespace software, counting the distribution of MPs in different soils, analyzing the sources and types of MPs, integrating the accumulation and fate of MPs, and summarizing methods of separation and identification MPs in soil.

The research on MPs in soil is sparse, with limited funding. Importantly, the annual average growth rate of MPs discharge into farmland exceeds into marine, and the comparability of detection results is poor. Research has found, synthetic textiles, tyres, and urban dust are the main sources, which mainly introduce through atmospheric sedimentation, sewage irrigation, sludge farming, and the use of agricultural film. What’s more, MPs in soil may have the risk of leaching from groundwater and contaminating it. Therefore, it is essential to establish a standard quantitative method for extracting and identifying microplastics in soil to better control their impact on the planting industry.

The MPs in soil seriously affect the growth of plants. Nutrient transfer and intergenerational transmission effects pose potential risks to human health. Consequently, the degradation of MPs by microorganisms in soil is an environmentally friendly and economically worthy topic for in-depth research.