Abstract

Aim: This study aimed to determine the concentrations of heavy metals (Pb, Cr, Zn, and Hg) in drinking water sources in Maiduguri, Nigeria, and compare the results with World Health Organisation (WHO) and Standard Organisation of Nigeria (SON) standards to assess public health risks.
Method: A total of 90 water samples from various borehole types and surface sources were analyzed using spectrophotometry. Non-carcinogenic health risks were evaluated using the Hazard Index (HI) based on the Chronic Daily Intake (CDI) for both adults and children.
Result: The analytical results showed that Lead (mean: 0.63 ± 0.12 mg/L; range: 0.00-0.60 mg/L) and Chromium (mean: 0.33 ± 0.16 mg/L; range: 0.14-0.58 mg/L) concentrations significantly exceeded the World Health Organisation (WHO) and Standard Organisation of Nigeria (SON) permissible limits of 0.01 mg/L and 0.05 mg/L, respectively. The Hazard Index (HI) exceeded 1.0 across all water source types (Surface Dam: 1.27; Shallow Borehole: 1.32; Deep Borehole: 1.52), with children at particularly elevated risk.
Conclusion: The study reveals that drinking water in the investigated areas is heavily contaminated with Pb and Cr relative to international and national standards. These findings necessitate immediate water quality management strategies to protect the local population, particularly children, from long-term heavy metal toxicity.

Key words: Heavy Metals; Health Risk; Drinking water; Maiduguri; Hazard Quotient