Evaluation of drinking water quality and non-carcinogenic and carcinogenic risk assessment of heavy metals in rural areas of Kurdistan, Iran

Abstract Heavy metals and nitrates are important causes of groundwater pollution and threaten human health worldwide, so the purpose of this study is to determine the concentration of anions cations, and heavy metals in rural drinking water resources and to estimate the health risks (non-carcinogenic and carcinogenic) for children, women, and men Chemical analysis and testing were performed on 138 water samples taken from rural drinking water resources in Kurdistan, Iran. The health risk assessments were evaluated using hazard quotient (HQ), hazard index (HI), and lifetime cancer risk (CR) according to the methods recommended by the United States Environmental Protection Agency. It was found that, except for arsenic (max. concentration 54 mg/l) and nitrate (max. concentration 225 mg/l), the contents of other parameters were lower than the allowable standard levels assigned for drinking water. It should be mentioned that the amount of arsenic and nitrate in 10.8% and 14.5% of the samples exceeded the standard limit, respectively. Regarding fluoride, its concentration was lower than the minimum recommended standard in 80% of the samples with average concentration of 0.55 mg/l. The maximum HQ values for arsenic in men, women, and children in the study area were 4.73, 5.5, and 11, respectively. Similarly for nitrate were 0.55, 0.83, and 1.65, respectively, so that 40% of the water resources of some villages can have non-carcinogenic effects for children. The findings show that in a number of villages, consumers are at the carcinogenic risk of Arsenic. It can be concluded that arsenic and nitrate have been the cause of adverse health effects in the study areas. Therefore, various control programs such as reducing and monitoring the application of chemical fertilizers and pesticides, controlling agricultural runoff, replacing water resources, and household water treatment are recommended to protect the health of consumers.