Microplastic Pollution in Pavement Sediments of Beijing: Abundance, Characteristics, and Ecological Risk.

Pavement sediments are a significant source of microplastics (MPs) in urban environments and a major contributor to stormwater runoff pollution. In this study, we investigated the abundance and characteristics of microplastics in Beijing's major road networks and functional zones by collecting road sediment samples, and assessed the ecological risks posed by microplastics in road surface sediments in Beijing. The results showed that the average abundance of microplastics in Beijing pavement sediments was 960.9 items/kg, with the highest abundance observed in commercial areas (1505.7 items/kg). The main characteristics of microplastics were black in color (22.4%), fibrous in shape (55.29%), small to medium in size (10-500 µm, 46.95%), with polyethylene (PE) being the most abundant polymer type (30.69%). The Polymer Risk Index (PRI) method showed clearer differentiation of spatial risk patterns in the Beijing study area, with 5 low-risk sites, 8 medium-risk sites and 15 high-risk sites among the sampling sites.