Exposure and health Risk Assessment of PHEs (Pb, Cd, Cu, Fe) in Agricultural Soil in Kerman City,Southeast of Iran

Abstract

Abstractpotentially harmful elements (PHEs) are essential among environmental pollutants due to their non-degradability and physiological effects on living organisms in low concentrations, which gradually accumulate in the soil due to low mobility. These elements eventually enter the food cycle and threaten the health of humans and other organisms through their accumulation in the soil. Therefore, studying the distribution of concentration PHEs and examining soil pollution is necessary to maintain environmental quality. The contaminants in agricultural soils can, directly and indirectly, pose significant risks to human health through several paths, including ingestion, inhalation, and skin contact. In this research, the human health risk assessment of PHEs in the agricultural soils of Kerman City has been carried out. It is a descriptive-cross-sectional study in which 620 soil samples were taken from the agricultural lands and 40 samples including 20 samples of rock (lime, conglomerate) and 20 samples (wind sediments, alluvium and platy sediments) as well as 41 soil samples including 20 samples from residential areas and 20 samples from polluting areas (car repair shops, gas stations, battery productions, car painting shops and landfills) have been taken in Kerman City in 2019, The concentrations of cadmium, lead, iron, and copper have been determined by the graphic furnace atomic absorption system. The Nemrow comprehensive index method has been applied for the qualitative and quantitative assessment of soil pollution to determine the toxic source and artificial effects. The carcinogenic and non-carcinogenic risk of agricultural soil PHEs for human health has been assessed for both groups of children and adults using the recommended method proposed by the US Environmental Protection Agency (USEPA). The results have shown that the mean concentration of PHEs except for copper in the studied agricultural soils is higher than the natural background. In addition, the obtained results, based on the Nemrow index [contamination factor (CF) and pollution loading index (PLI)], have shown that the studied agricultural soils have been heavily contaminated by lead (CF > 3), and the contamination levels of the target PHEs in all areas have been in the range of low pollution (PLI ≤ 1). Furthermore, the results obtained by the geo-accumulation index (Igeo) showed that the accumulation of lead in agricultural soils of Kerman City has been in the range of low pollution (0 < Igeo < 1) to medium (1 < Igeo < 2). The other metals are within the limits of non-contaminated values. The hazard index (HI) for children and adult groups is lower than one in the studied agricultural soils. The ingestion is the main pathway of carcinogenic risk for lead and cadmium in both children and adult groups. Correspondingly, the total carcinogenic risk for children and adults (TCR)is within the acceptable level (1×10-4- 1×10− 6). In general, values of both carcinogenic and non-carcinogenic risks in the children group are higher than that of the adults.