Health risk evaluation of heavy metal levels in drinking water sources across Damaturu, Yobe State, Nigeria

Abstract

Access to safe drinking water is a critical public health concern, particularly in semi-arid regions such as Damaturu, Yobe State, Nigeria, where anthropogenic activities and environmental factors may increase heavy metal contamination. This study aimed to evaluate the levels of selected heavy metals in drinking water sources and assess their potential health risks. Twenty water samples were collected using a simple random sampling technique, each labeled with a unique identification code and georeferenced with GPS coordinates. Heavy metal concentrations were determined using a Micro Plasma Atomic Emission Spectrometer. The mean concentrations obtained were 0.4355 mg/L for arsenic (As), 0.076 mg/L for lead (Pb), 0.0271 mg/L for cadmium (Cd), 0.915 mg/L for chromium (Cr), 0.29615 mg/L for nickel (Ni), 0.01706 mg/L for zinc (Zn), 3.4249 mg/L for manganese (Mn), and 11.0635 mg/L for magnesium (Mg). Risk assessment revealed that the estimated daily intake of As, Pb, Cd, and Cr exceeded the permissible limits set by the World Health Organization (WHO) and United States Environmental Protection Agency (USEPA). Furthermore, hazard quotients (HQ) and hazard indices (HI) were greater than one, indicating significant non-carcinogenic risks, while incremental lifetime cancer risk (ILCR) values surpassed acceptable thresholds, suggesting elevated carcinogenic risks. These findings highlight a substantial threat to public health from long-term consumption of contaminated water in Damaturu. Continuous monitoring, public awareness, and the enforcement of regulatory interventions are therefore essential to mitigate exposure and safeguard water quality in the region.