Ecological and health risk assessment and anthropogenic sources analysis of heavy metals in different types of urban road dust

Abstract

In aerosol science, heavy metal pollution is a hot issue, particularly when it comes to road dust in densely populated cities. Herein, 65 different types of road dust samples from Xiangtan City were examined for their degree of heavy metal pollution and associated ecological risks using the Geo-accumulation Index (IGEO), Pollution Load Index (PLI), and Potential Ecological Risk Index (PERI). The health risks of heavy metals were quantified and analyzed using human exposure and health risk assessment models. Heavy metal pollution sources and their contribution rates were determined using the Positive Matrix Factorization (PMF) model. The average contents of Cu, Pb, Zn, Cd, and Cr in road dust samples from Xiangtan were 91.295 mg/kg, 549.631 mg/kg, 536.799 mg/kg, 0.432 mg/kg, and 115.596 mg/kg, respectively. In different types of road dust, Cd content was the lowest, and Pb content was the highest except for samples from the main road. Furthermore, Pb had the highest IGEO value, with all sample sites exhibiting strong pollution levels or higher. The combined PERI categorized the heavy metals under moderate ecological risk. The health risk assessment of the heavy metals showed that the noncarcinogenic risk of road dust to adults was within acceptable limits. Conversely, the noncarcinogenic risk of Pb to children was notable, the carcinogenic risk of Cd to humans was < 10−6, and the carcinogenic risk of Cr surpassed the human body’s tolerable range. Finally, the primary sources of heavy metals in road dust were industrial activities (32.05 %), transportation (34.90 %), and a combination of transportation, industrial, and construction activities (33.05 %).