The characteristics of heavy metal pollution in surface dust in Tangshan, a heavily industrialized city in North China, and an assessment of associated health risks

With the rapid development of industrialization and urbanization, surface dust has an increasing impact on people's living environment and human health. Tangshan is an important heavily industrialized city in North China. To understand the heavy metal pollution associated with surface dust in Tangshan City, and its health risks, a total of 162 surface dust samples were collected in the central downtown area of Tangshan City. The concentrations of eight heavy metals were measured (As, Cd, Hg, Pb, Cr, Cu, Zn, and Ni). The results indicate that the heavy metals show different degrees of enrichment. As, Hg, Cr, and Ni in surface dust are mainly sourced from fuel coal and industrial production activities, while Zn and Cu are mostly sourced from metal smelting and urban transportation. Pb is associated with urban transportation, and Cd is associated with industrial activities such as metal smelting, and urban transportation. The pollution levels of As, Cr, Cu, and Ni in surface dust range from the non-pollution to moderate pollution classifications, while Hg and Pb are classified as moderate pollution, Zn ranges from moderate pollution to strong pollution, and Cd concentrations are classified as strong pollution. The total ecological risk level of surface dust is very high, with a high ecological risk posed by Cd, a very strong ecological risk posed by Hg, and slight ecological risks posed by As, Cr, Pb, Zn, Cu, and Ni. The total non-carcinogenic risk (HI) for children and adults is ranked As > Pb > Cr > Cd > Zn > Ni > Cu > Hg. The HI of children through different exposure pathways is higher than that for adults. Hand-mouth intake is the largest contributor to the HI. The HI of children for hand-mouth intake is higher than adults. Ni, Cr, As, and Cd in surface dust do not pose a carcinogenic risk through respiration pathways.