Characteristics of heavy metals in road dust: An overview of South Korean cases

The urbanization and industrialization of our society necessitate the extension of road traffic systems. Road dust generated by road traffic is harmful to the human respiratory system. In particular, heavy metals adsorbed on road dust can pose substantial risks to human health owing to their toxicity, environmental longevity, and ability to accumulate in the human body. Although the evaluation of the concentration of heavy metals in road dust is essential for understanding their sources and risks to human health, there is a lack of comprehensive information on the heavy metal content in road dust in South Korea. In this review, sampling methods and analytical techniques for characterizing the contents of various heavy metals in road dust collected from different regions of South Korea are discussed. Cu, Zn, Cd, Pb, Ni, Cr, As, and Hg are the most frequently found heavy metals in road dust, and their concentrations are strongly associated with the sampling locations (e.g., industrial vs. residential sites and rural vs. urban areas) and particle size of the road dust. Road dust samples collected from more industrialized regions tend to contain more heavy metals. Further, smaller dust particles are likely apt to contain more heavy metals. The application of non-destructive analytical techniques is also necessary for the accurate characterization of heavy metals in road dust.