The distribution and characteristics of soil microplastics pollution: Evidences from different land use.

Microplastic pollution in terrestrial ecosystems is a global concern, yet its distribution across land-use types remains poorly understood in plateau regions. To investigate the distribution of microplastics (MPs) across land-use types, 86 soil samples were collected from four land-use types in Yunnan Province: dryland farmland (DF), plantation (P), road greenbelt (RG), and forest (F). MPs abundance was significantly higher in P (6211 ± 6580 items kg-1) and RG (5728 ± 4392 items kg-1) soils than in F (1650 ± 917 items kg-1) (P < 0.05), with DF soils at intermediate levels (3042 ± 2442 items kg-1). Effect size analysis (η² = 0.124 for 0-5 cm; η² = 0.152 for 5-10 cm) indicated that land-use type explains approximately 12-15% of the total variation in MPs abundance. The majority of microplastics were 0-0.5 mm; amongst the extractable microplastics, polyethylene (PE) and polypropylene (PP) are the predominant types. Soil MPs abundance in DF increased with mulching duration (within 0-25 years). In P soils, MPs abundance was significantly higher with organic than chemical fertilizer (P < 0.05). In RG soils, MP abundance from medium-sized cities was significantly higher than that in small cities. These findings provide critical insights for targeted mitigation strategies to safeguard soil quality and ecosystem health in plateau regions.