Spatial distribution, contamination levels, source identification and human health risk assessment of potentially toxic elements in street dust in urban area in Libya

Street dust samples were collected from 31 sampling sites which were classified into four different groups in Zawiya, Libya, covering different traffic, city center, junkyards, oil refinery, farming, and household activities. Since the potentially toxic elements (PTEs) in street dust have a non-negligible impact on health, the aim of this study is to investigate the sources, pollution level and human health risk of PTEs. In this study, wavelength distribution X-ray fluorescence device was used to determine the concentration of PTEs. The spatial distribution, contamination levels, sources, and human health risks of PTEs in road dust were evaluated. The PTEs content of the street dust were found as Cr>Mn>Zn>Pb>Cu>Ni>Co. The average concentration of most PTEs (Co, Cu, Mn, Ni and Zn) was higher in junkyards and heavily traffic areas than in other areas. Cobalt and Cu has the highest geo accumulation index (Igeo) values, and due to these values, the study area was evaluated as moderately to heavily contaminated. Enrichment factor (EF) values of Cr, Pb and Zn exhibited a significant enrichment, indicating that some sampling sites were affected by anthropogenic sources. There was no lifetime cancer risk for exposure to PTEs in street dust by inhalation in Zawiya. Each hazard quotient (HQ) and hazard index (HI) for all PTEs were less than 1, indicating that exposure to PTEs in street dust did not have significant non-carcinogenic risks for both adults and children. In conclusion, Zn, Pb, Cu, Mn, and Cr were represented by the largest portion of the total data variance in the principal component analysis (PCA), and they were positively correlated. It was seen that study area was influenced by anthropogenic sources rather than natural sources, but there was no health risk.