The concentration, characteristics, and probabilistic health risk assessment of potentially toxic elements (PTEs) in street dust: a case study of Kashan, Iran

Exposure to potentially toxic elements (PTEs) via dust inhalation can endanger human health. In this regard, the dust samples from the streets of Kashan, Iran were collected to investigate the concentration of some PTEs such as Fe, Zn, Cu, Pb, Cr, Ni, and Cd by the aid of an inductively coupled plasma mass spectrometry (ICP-MS) while distribution and geoaccumulation analysis also were carried out. Also, the related health risk due to different exposure pathways of PTEs for the inhabitants of this city was assessed. The mean concentration of PTEs in the street dust was summarized as Fe (1.66 × 10⁴ mg/kg)>Zn (2.37 × 10² mg/kg)>Cu (4.56 × 10¹ mg/kg)>Pb (4.52 × 10¹ mg/kg)>Cr (3.71 × 10¹ mg/kg)>Ni (1.36 × 10¹ mg/kg)>Cd (4.30 × 10⁻¹ mg/kg). The rank order of PTEs based on mean geoaccumulation index (GAI) (I _geo) was Pb (2.77)>Zn (1.92)>Cu (1.06)>Fe (−0.64)>Cd (−0.90)>Cr (−0.97)>Ni (−1.15). Also, the rank order of target hazard quotient (THQ) for both adults and children was Fe > Pb > Cr > Zn > Cu > Ni > Cd, while the cancer risk (CR) for both adults and children was Cr > Ni > Cd. The total target hazard quotient (TTHQ) was measured as less than 1.0; therefore, residents of Kashan are not at considerable non-carcinogenic risk. Also, CR of Ni, Cd, and Cr exceeded the threshold value of 10⁻⁶; therefore, residents of Kashan are at considerable carcinogenic risk due to street dust in Kashan city. As a conclusion, approaching some controlling plans to decrease in emission of PTEs to ambient air is necessary.