Assessment of the health risk and geo-accumulation of toxic metals in agricultural soil and wheat, northern Iran

The current work was conducted to study the concentrations of heavy metals (HMs) in farming soil and wheat and compute their geological and health indexes, including geo-accumulation index (I_geo), chronic daily intake (CDI), hazard index (HI), hazard quotient (HQ), and cancer risk (CR). In general, 256 samples were collected from agriculture soil (AS) and wheat in Kalaleh and Aq Qala areas, northern Iran. The average rates of Cd, Cu, Pb, and Zn were detected to be 0.28, 25.24, 15.44, and 60.33 mg·kg⁻¹, respectively, for AS and 0.01, 8.85, 0.73, and 33.81 mg·kg⁻¹ for wheat, respectively. Based on the results, the HQ and HI levels for investigated HMs were lower than l. So, the health risk of HMs exposure for adults and children was low. CR levels for Pb in AS for both children and adults were observed greater than the threshold value. Accordingly, lead-contaminated soil will be carcinogenic if ingested by children. On the other hand, the exposure to Pb (through wheat) and Cd (through both soil and wheat) had the acceptable CR level for all groups. As a result, for an extended period, there are no significant health consequences for children and adults.