Effects of Microplastics Migration on Farmland Soil Physical and Chemical Properties Under Leaching Conditions

Microplastics (MPs) in soil can affect soil quality, and interfere with the material cycle and energy flow of terrestrial ecosystem. To explore the migration of MPs in soil and its effect on farmland soil quality, a soil column experiment was conducted to simulate the migration of MP particles in soil under rainful condition. The results showed that at a mass ratio of 2%, the migration capacity of polystyrene, polyethylene, polypropylene, polyvinyl chloride, and polylactic acid MPs in the soil columns was similar. The presence and type of MPs had no significant effect on soil bulk density. The influence of MPs on the quantity of water stable macro-aggregates (> 0.25 mm) was more significant in the top soil layer (0–5 cm) where the MPs were added than in the middle and bottom layers (5–20 cm). Under leaching, MPs decreased the available phosphorus concentration in soil.The results of this study can improve the understanding of the effects of MPs on the soil quality and provide reference information for the environmental risk assessment of MPs in farmland soils.