Pollution and health risk assessment of heavy metals in agricultural soil, atmospheric dust and major food crops in Kermanshah province, Iran.

A total of 167 samples of agricultural soil, atmospheric dust and food crops (wheat and maize) were collected, and four heavy metals, including Zn, Cu, Ni, and Cr, were analyzed for their concentrations, pollution levels and human health risks. The mean heavy metal contents in the agricultural soil and atmospheric dust were exceeds background values and lower than their IEQS (Iranian Environmental Quality Standard) with an exception of Ni. A pollution assessment by Geo-accumulation Index (Igeo) showed that the pollution levels were in the order of Ni> Cu> Cr> Zn for agricultural soils and Ni> Cu> Zn> Cr for atmospheric dust. The Ni levels can be considered "moderately to heavily contaminated" status. The human health risk assessment indicated that non-carcinogenic values were below the threshold values (1), and main exposure pathway of heavy metals to both children and adults are ingestion. The carcinogenic risks values for Ni and Cr were higher than the safe value (1â€¯× 10-6), suggesting that all receptors (especially wheat) in Kermanshah province might have significant and acceptable potential health risk because of exposure to Ni and Cr. The carcinogenic risk for children and adults has a descending order of Ni> Cr, except for wheat. These results provide basic information on heavy metal contamination control and human health risk assessment management in the Kermanshah province.

Mapping of human health risks arising from soil nickel and mercury contamination.

Elevated contents of mercury (Hg) and nickel (Ni) in soils and foodstuffs can threaten human health. As contents of these metals in soil, water and food vary from place to place, the associated risks will also be different in various parts of a region and it should be considered for environmental decision making and human health management. The objective of this study was to map the variation of human health risks related to Ni and Hg in soil, water and foodstuffs across an entire region, in province of Hamedan western Iran as an example case. Risks were calculated using the methods proposed by USEPA. The risk maps showed that total non-cancer relative risks of Ni and Hg were much higher than 1 (critical level). Risk of Ni in Razan and Kaboudarahang was higher than other counties. For some areas, relative non-cancer risks associated with exposure to Hg were estimated up to 7 and 11 in children and adults respectively. Consumption of plant foods particularly wheat was found to be the major route of human exposure to Ni and Hg. Soil ingestion was found to be another important route of human exposure to these metals.