Carcinogenic and Non-Carcinogenic Human Health Risk Assessment of Heavy Metals in Tap Drinking Water from Rural Communities in Northern Iran Using the United States Environmental Protection Agency Model

Background: Chronic exposure to heavy metals (HMs) in drinking water poses a significant environmental risk globally and may have serious implications for human health. Objectives: This study focuses on assessing the carcinogenic and non-carcinogenic health risks associated with six heavy metals in the Anzali lagoon area of northern Iran. Methods: We evaluated the average concentrations of cadmium (Cd), lead (Pb), chromium (Cr), nickel (Ni), copper (Cu), and zinc (Zn) in tap drinking water collected from eleven rural communities. Additionally, we measured pH, total dissolved solids, and temperature. The health risks related to HM ingestion were assessed for both adults and children based on U.S. Environmental Protection Agency (EPA) guidelines. A total of ninety water samples were analyzed using inductively coupled plasma atomic emission spectroscopy (ICP-AES). Carcinogenic and non-carcinogenic health risks were evaluated through the incremental lifetime cancer risk (ILCR) and hazard quotient (HQ), respectively. Results: The average level of Pb exceeded the permissible limits set by WHO and Iranian national standards in five communities, affecting ۴۸.۸% of the samples. Furthermore, one community had Pb levels surpassing U.S. EPA standards in ۲۲.۲% of its samples. The concentrations of other heavy metals were within acceptable limits established by the U.S. EPA, WHO, and Iranian standards. Conclusion: The carcinogenic risk of heavy metal ingestion for both adults and children was estimated to be between ۱۰^-۶ and ۱۰^-۴, indicating a generally tolerable cancer risk. However, this risk was notably higher in children compared to adults. The non-carcinogenic risk associated with selected heavy metals was below the safe limit (<۱) across all communities for both age groups. Nonetheless, one community's concentrations of heavy metals and associated non-carcinogenic risks warrant further investigation, particularly concerning children's exposure.

کلیدواژه ها:

heavy metal ، health risk ، drinking water ، drinking water ، carcinogenic risk ، non-carcinogenic risk