Source and health risk assessment of arsenic in the water resources of Takab mining area

Arsenic is one of the heavy metals having harmful effects on human health if enters into the environment and water resources, so the major challenge of arsenic exposure is related to drinking water. The study area is Takab watershed in West Azarbaijan, which includes two large Zarshouran and Agh Dareh gold mines in Carlin type. Carlin gold mines are sulphidic that are able to pollute the downstream environmental resources such as arsenic. In this work, the carcinogenic and non-carcinogenic health risks associated with arsenic was evaluated for the human community, who are living in Takab watershed and are exposed to arsenic through oral and dermal pathways with contaminated water sources . 45 water samples were randomly collected from surface and groundwater resources in the study area with regard to expert judgment and the distribution points, analyzed by ICP-MS method. Then, the health risk was assessed using by target cancer risk (TR), risk coefficient (HQ) and index hazard (HI). The total results showed that arsenic contamination is derived from volcanic activities and Quaternary alteration and gold mining activities in the east and north of the region. Most of the samples were revealed a range of 9-10 and -100 to -250 mV as pH and oxidation-reduction potential, respectively, which indicates the predominance of arsenate species (As5+) in the form of H2AsO4-. HQ and HI values are more than 10 in 52% of the samples, which indicate the high health risk in people living in the study area. Carcinogenic risk level varies from 0 to 2×10-7, which shows no carcinogenic risk to very high risk by arsenic contamination in water resources. Overall, there are both risks of carcinogenesis and non-cancerous impact in the east and north of the region for intake by ingestion, drinking and skin contact due to water contamination from the natural and anthropogenic sources. Therefore, it is recommended to pay special attention to continuous monitoring for potential contaminant, different methods for preventing exposure to polluted water resources and treatment methods in order to minimize the health risk of the population.