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

Area of Science:

• Environmental Science
• Urban Ecology
• Polymer Science

Background:

• Pavement sediments are a key source of microplastics (MPs) in urban settings.
• MPs in road runoff contribute significantly to stormwater pollution.
• Understanding MP pollution in urban road networks is crucial for environmental management.

Purpose of the Study:

• To investigate the abundance and characteristics of MPs in Beijing's road sediments.
• To assess the ecological risks associated with MPs in urban pavement.
• To map the spatial distribution of MP pollution and associated risks.

Main Methods:

• Collection of road sediment samples from major road networks and functional zones in Beijing.
• Analysis of MP abundance, color, shape, size, and polymer type.
• Application of the Polymer Risk Index (PRI) to evaluate ecological risks.

Main Results:

• Average MP abundance in Beijing pavement sediments was 960.9 items/kg, highest in commercial areas (1505.7 items/kg).
• Predominant MP characteristics: black color (22.4%), fibrous shape (55.29%), small to medium size (10-500 µm, 46.95%), and polyethylene (PE) polymer (30.69%).
• The Polymer Risk Index identified 5 low-risk, 8 medium-risk, and 15 high-risk sites.

Conclusions:

• Beijing's road sediments contain significant levels of microplastics, posing ecological risks.
• Commercial areas exhibit higher microplastic contamination.
• The Polymer Risk Index effectively differentiates spatial risk patterns, aiding targeted mitigation efforts.