Human Health Risk Assessment of Heavy Metals in Surface Soil

Background and Soil heavy metal contamination is a major environmental concern. Contaminants in urban soils can directly pose significant human health risks through oral ingestion, particle inhalation, and dermal contact. The purpose of this study was to determine the health risk of heavy metals in surface soils in Aran-Bidgol, Iran.
A descriptive cross-sectional study was performed in which 135 topsoil samples were collected from Aran-Bidgol (in Isfahan province) and the metal concentrations of Cd, Pb, Ni, Zn and Cu were determined. Carcinogenic and non-carcinogenic human health risks of heavy metals in surface soils through oral ingestion, inhalation and dermal contact pathways for children and adults were evaluated using the US Environmental Protection Agency (EPA) approved method.
The mean concentrations of Cd, Pb, Ni, Zn and Cu, were 0.72, 11.41, 29.87, 48.59, and 14.82 mg/kg, respectively, which all exceeded the background values. The highest non-cancer risks for both children and adults were found in Pb (12.63 and 0.82, respectively) while the lowest values were observed in Zn (0.3 and 0.04, respectively). The total accumulated non-cancer risk (HI) of all heavy metals for children and adults were more than 17 and 2, respectively. The cancer risk values were 6.37E-06 (Cd), 6.78E-06 (Pb), and 3E-04 (Ni) for children and 1.12E-06 (Cd), 1.19E-06 (Pb), and 6.19E-05 (Ni) for adults.