Concentration of Microplastics in Road Dust as a Function of the Drying Period—A Case Study in G City, Korea

Abstract

Microplastics (MPs) are plastic particles < 5 mm in diameter, which are detected in air, soil, and water, causing various environmental problems. In total, 37.3% of MPs are generated from point pollution sources and 62.7% from non-point sources; most of the non-point-source MPs are from vehicles tires, road-marking paint, and bitumen used in road pavements. In this study, the concentrations of MPs generated from roads in Goyang city, South Korea, were examined in terms of the drying period (0, 1, 2, or 3 d). Road dust sampling was performed at the kerb and quantitative and qualitative analyses were conducted for each sample. The MP concentrations were 552 (±39) MPs g−1 for a 0 d drying period and 1530 (±602) MPs g−1 for a 3 d drying period, confirming that the MP concentration in road dust increased with the increase in drying period. Among the detected substances, black particles accounted for the highest proportion (72%) and were found to be bitumen and tyre particles. This study also confirmed that the MPs accumulated on roads were washed away when rainfall exceeded a certain amount.