Human Health Risks Associated with Potentially Harmful Elements from Urban Soils of Hamedan City, Iran

Previous studies have shown that certain urban elements and arsenic are significantly concentrated in the surface soils of Hamedan, the largest city in western Iran. This study was carried out to assess the non-cancer and cancer risks from exposure to these potentially harmful elements (As, Cd, Cr, Cu, Ni, Pb, and Zn) for Hamedan residence. In so doing, thirty-one urban and three background soil samples were analyzed by ICP-MS and the Risk Assessment Model established by the USEPA was applied to assess the health risk. It was found that the hazard index values for all the concerned elements are below 1, which indicates negligible to low non-carcinogenic risk for the exposed population. Nevertheless, some close to threshold values were recognized for As, Cr, and Pb implying that these elements have the potential to cause non-cancer risk for Hamedan citizens in case of long-term overexposure. The contribution of HQ-ingestion to total HI was the highest while the health effect associated with the inhalation exposure was trivial. Children were found to be more susceptible to potentially harmful elements than adults. The cancer risk calculation revealed that both children and adults are at increasing risk of developing cancer over a lifetime through ingestion, inhalation, and skin contact. All of the verified elements exceeded the tolerable level (1 x 10(-6)) of cancer risk however arsenic and chromium were found to be the most carcinogenic elements followed by Pb, Ni, and Cd. The carcinogenic risks were moderate for adults and high for children. This study indicates the necessity of designing effective strategies to reduce elemental pollution and to mitigate adverse human health effects of PHEs in Hamedan.