Characteristics and health risk assessment of heavy metals in street dust for children in Jinhua, China.

Street dust and soil samples were collected from three study areas in Jinhua, China: a commercial area and two urban districts. The concentrations of nickel (Ni), lead (Pb), copper (Cu), cadmium (Cd), and particularly zinc (Zn) in street dust exceeded soil background values and Chinese soil screening safe levels in some areas. Zn and Cd concentrations in street dust appeared to pose health concerns in the majority of sample sites, but their levels in soils were noticeably lower, indicating possible contamination from atmospheric deposition. Of the three areas, the most severe pollution occurred in Jindong (JD) District. Practically all the samples from JD District showed contamination to some degree. Based on pollution indices, the contamination levels of heavy metals among the studied sites were ranked in the following descending order: JD District > commercial area (CA) > Wucheng District. Source metal identification assessment revealed that the majority of metals in street dust from Jinhua were significantly related to industrial and traffic activities. Health risk assessment was performed based on the US-Environmental Protection Agency model, and the results showed that virtually, no health risk existed from exposure to individual metals in dust particles. However, the noncarcinogenic risk exponentially increased through exposure to various metals in dust. Thus, the majority of hazard index values surpassed the acceptable level. For carcinogens, the carcinogenic risks of each metal did not supersede the acceptable range for children. This observation demonstrates that although the carcinogenic risk is acceptable, the noncarcinogenic risk remains a genuine health concern for local children.