Exploring the spatial distribution of dissolved heavy metals and health risk assessment of cadmium in groundwater: A case study in Oued M’Zab region, Algeria

Background: Heavy metals are one of the most harmful groundwater contaminants due to their toxicity and persistence in the environment. This study aimed to assess the impacts of heavy metals on the quality of groundwater within the M'Zab Valley used for human consumption and irrigation and its potential impact on public health. Methods: In this study, the samples taken from eight phreatic aquifer wells situated along the M'Zab Valley, from upstream to downstream, were analyzed, and chronic daily intake (CDI) of cadmium, hazard quotient (HQ), and target organ risk (TOR) for the kidney were computed for child, infant, and adult age groups. Results: It was revealed that the superficial aquifer water is of poor quality and frequently exceeds the drinking water standards, particularly for Cd, Cr, and Zn, which poses a health risk for inhabitants. The study found that the CDI values for Cd for each age group (infants, children, and adults) were below the safe limit established by the World Health Organization (WHO), but the data reveals that the concentration of the HQ is considerably greater in infants than in children and adult groups, considering that infants have the highest estimated daily intake of Cd and TOR for the kidney. Thus, infants may be exposed to a greater health risk associated with cadmium exposure. Conclusion: According to the results of the present study, continuous monitoring of water quality and treatment measures to reduce elevated pollutant levels that harm human health are strongly advised to preserve and safeguard groundwater quality from various forms of pollution.