Determining the indicators of carcinogenic risk assessment of heavy elements in the water resources of the Torbat-e Jam city in 2022

Background and Heavy metals are among the most critical contaminants in drinking water, owing to their stability and accumulation capability in living tissues and the food chain. Consequently, this study was conducted to determine the carcinogenic and non-carcinogenic risk assessment indices for heavy metals in the water sources of Torbat-e Jam City in 2023. Samples were collected from 16 groundwater sources and the surrounding soil of Torbat-e Jam City during the summer and autumn of 2023. Concentrations of five heavy metals - arsenic, mercury, lead, cadmium, and copper - were measured using a Varian atomic absorption spectrometer. Finally, the health risk levels for three different groups were calculated using indices provided by the Environmental Protection Agency (EPA) of the United States. The average concentrations of heavy metals in water during summer were as follows: arsenic: 0.0027 ± 0.0035 mg/L, mercury: 0.00019 ± 0.00035 mg/L, lead: 0.0011 ± 0.0023 mg/L, cadmium: 0.0002 ± 0.0002 mg/L, and copper: 0.0046 ± 0.0078 mg/L. In autumn, the concentrations were arsenic: 0.0082 ± 0.0081 mg/L, mercury: 0.0018 ± 0.0008 mg/L, lead: 0.0056 ± 0.0058 mg/L, cadmium: 0.00084 ± 0.00083 mg/L, and copper: 0.0091 ± 0.0068 mg/L. In soil, the concentrations were arsenic: 0.011 ± 0.053 mg/L, mercury: 0.0086 ± 0.0068 mg/L, lead: 0.131 ± 0.186 mg/L, cadmium: 0.0002 ± 0.00047 mg/L, and copper: 0.12 ± 0.24 mg/L. The study found the non-carcinogenic risk levels of the examined heavy metals to be low. However, the carcinogenic risk level for arsenic was very high in both seasons, for cadmium was moderate in autumn, and for the other elements, it was within the standard limits. Given the high carcinogenic risk of arsenic for women, men, and children in both summer and autumn, continuous monitoring of arsenic levels should be a priority for regulatory agencies.