Risk assessment of toxic metals in street dust from a medium-sized industrial city of China

• Pb and Co in the dust presented low to moderate ecological risk.
• The comprehensive ecological risks of metals studied in the dust were moderate.
• The non-cancer risks of the studied metals to residents are within the safe level.
• The cancer risks of As, Co, Cr and Ni are within the currently acceptable range.

The concentrations of toxic metals As, Co, Cr, Cu, Mn, Ni, Pb, V and Zn in street dust of Tongchuan, China were determined by wavelength dispersive X-ray fluorescence spectrometry. The risk of the analyzed metals to urban ecosystem and human health were evaluated by potential ecological risk index and human exposure model, respectively. The results show that, in comparison with Shaanxi soil, dust samples have elevated metal concentration as a whole expect for As, Mn, V and Ni. The assessment results of ecological risk indicate that the ecological risks of As, Cr, Mn, Ni, Cu, V and Zn in the dust were in the low level, while Pb and Co presented low to moderate level. Health risk assessment shows that ingestion was the main exposure route of all analyzed toxic metals in street dust to children and adults. The non-cancer risks of the studied metals to children and adults were within the safe range, and the cancer risks of As, Co, Cr and Ni were also within the currently acceptable range.