Health risk assessment of heavy metals in water consumed by families living in some villages of Mazandaran

In some villages of Mazandaran, drinking water may be polluted with various pollutants, especially heavy metals (HMs), due to the shallow depth of drinking water sources and the proximity of these sources to farmlands. Therefore, this study aimed to measure the HM pollution level of drinking water in some villages of Mazandaran province and to assess the attributed health risks.

HMs content of drinking water in 30 villages with separate water sources in Mazandaran province was measured. Concerning the HMs concentration and toxicity, and exposure route through water drinking, carcinogenic and non-carcinogenic risks were assessed using a Monte-Carlo simulation-based method.

The concentration values of arsenic, cadmium, chromium, nickel and lead in water were <1/0-4.26, < 0.05, <0.15-3.74, <0.3-10.89, and <0.8-4.68 µg/L, respectively. The hazard index (HI) values for non-carcinogenic risk due to the exposure to HMs through drinking of water in various age groups ranged from 3.04E-04 to 9.94E-04. Values of cumulative excess lifetime cancer risk (ELCRT) for As and Cr were 9.72E-08 and 6.13E-08, respectively.

The results of this study showed that, fortunately, the concentration of metals in drinking water in the studied area was much lower than the national standards and the attributed health risk. Therefore, the drinking water sources in the studied villages had acceptable quality. However, due to the existence of rice paddies in some villages of Mazandaran province, continuous monitoring of pollution levels in the drinking water sources of these areas is essential.