Health risk assessment of heavy metals in roadside soil along the Hemmat Highway of Tehran, Iran, in 2014

Background: The present study investigated the impact of land use on health risks (cancerous and non-cancerous) of heavy metals in soil along the Hemmat Highway of Tehran, Iran. Materials and Methods: A total of 28 soil samples were collected in August 2014 from the roadside soil of the Hemmat Highway. The collected samples were air-dried and digested, and then, analyzed for heavy metals using an atomic absorption spectrophotometer (AAS). Non-carcinogenic and carcinogenic health risks were calculated for different land uses (green space, residential area, under construction, and natural) along the Hemmat Highway. Results: The hazard index (HI) of Pb, Zn, Cd, Cr, and Ni was, respectively, 0.28, 0.19 × 10-2, 0.032, 0.043, 0.006 for children, and was 0.037, 0.24 × 10-3, 0.014, 0.012, 0.76 × 10-3 for adults. Carcinogenic risk of metals was analyzed for Cd, Cr, and Ni. The carcinogenic risk ‎of Pb, Ni, Zn, and Cd was 0.144 × 10-7, 0.427 × 10-6, and 9.41 × 10-2, respectively. Conclusions: The carcinogenic risk levels of the three studied metals were < 10-6 with higher values attributed to Cr‎. HIs for all metals were lower than their threshold values, indicating nil health hazards. The results of risk assessment showed that the highest risk value was related to ingestion of Pb.