Pollution and health risks assessment of heavy metals of road dust in Korla City, Xinjiang

In order to evaluate the pollution risk of heavy metals in road dust of the oasis city, the authors collected a total of 54 typical road dust samples from Korla, Xinjiang, and analyzed the concentrations of Hg, Cd, As, Pb, Cr, and Cu elements. The pollution and potential health risk of heavy metals in road dust were analyzed on the basis of GIS technology and geostatistical analysis methods and by using the Pollution Load Index and the US EPA health risk assessment model. The obtained results indicate that the average concentrations of Hg, Cd, As, Pb, and Cu elements in the road dust of Korla City are less than the screening values of the Soil Environmental Quality-Control Standard for Soil Contamination of Development Land (GB 36600-2018), but the average concentration of Cr exceeds the corresponding screening value by factor of 9.90 times. The results of pollution assessment indicate that heavy metals in the collected dust samples are heavily polluted by Cr, without pollution by Hg, Cd, As, Pb, and Cu. The Pollution Load Index of heavy metals in road dust varies in the range of 0.0142~0.0522, with an average value of 0.0266, at the no pollution level. The spatial distribution patterns of the six heavy metals in road dust indicate that the high concentrations are distributed mainly in the northeastern and northern areas of Korla City. The results of health risk assessment indicate that the handmouth ingest intake is the dominant pathway of the average daily exposure and health risks of road dusts in Korla, and the health risk of heavy metals in road dust for children are higher than that for adults. The non-carcinogenic and carcinogenic risk of metals such as Hg, Cd, As, Pb, Cr, and Cu in road dust in Korla is within the safe range. As contributes most to non-carcinogenic risk, whereas Cr contributes most to carcinogenic risk of road dust in Korla City.