Cancer and Non-Cancer Risk of Arsenic in Drinking Water: A Case Study

: Arsenic is a toxic element, which is found naturally in water sources. Due to its high toxicity it has become a serious problem in drinking water sources and also affects the health of communities. Therefore, in the present study, risk estimation and the probability of adverse health effects of exposure to arsenic from drinking water was evaluated in the rural areas of Qom province. Water samples were taken from 44 rural areas with regard to the number of rural areas and also the type of water distribution systems. The intensity, duration and frequency of exposure to arsenic in drinking water were determined. Then the hazard quotient and cancer risks ware calculated. Results showed that more than 16% of the rural population was exposed to arsenic with level above 10 μg/L in the rural regions of Kahak County (10 ± 6.29 μg/L). Results of risk assessment showed that hazard quotient (HQ) were 1.7 and 2, while the cancer risk (CR) were 76 × 10-5 and 42 × 10-4 for 2 groups of age 1 and 2, respectively. The results indicated that the hazard quotient is higher than 1 (HQ > 1) for group 1 and group 2. For carcinogenic effects, the study indicated that the population in the Kahak region are exposed to arsenic in drinking water with the concentration of > 10 µg/L and they are at a very high risk for cancer, due to the fact that the cancer risk for the 2 groups are more than 7.6 and 42 times the environmental protection agency (EPA) criteria, respectively. Therefore it is recommended that at first, the source and water supply system in Kahak region is to be substituted with safe drinking water and to provide health facilities and screening tests for exposed populations.