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Abstract

Human health may be at risk if drinking water contains excessive amounts of heavy metals (HMs). To determine risks related to heavy metals, fifteen water samples were taken every month between July and September, 2024 from the communities of Abobo (Site A), Osara (Site B) and Osaragada (Site C) close to Confluence University of Science and Technology, Osara. These samples were tested for ten HMs (Cu, Fe, Ni, Zn, Co, Cd, As, Cr, Hg, Pb) with the aid of Atomic Absorption Spectroscopy. The average concentration ranges as follows: Fe (0.378-0.511 mg/l), Cu (1.643-1.720 mg/l), Ni (0.31-0.556 mg/l), Zn (0.17-0.271 mg/l), Cd (0.153-0.286 mg/l), As (0.122-0.141 mg/l), Cr (0.544-0.730 mg/l), Pb (0.236-0.284 mg/l), Hg (0.083-0.187 mg/l) and Co (0.103-0.251 mg/l). All measured HMs levels exceeded World Health Organization (WHO) guidelines, with the exception of Cu and Zn. For sites A, B, and C, the Heavy Metal Evaluation Index (HEI) readings were 137.7, 142.911, and 174.051, respectively, indicating poor water quality. The computed Hazard Quotient (HQ) and Hazard Index (HI) values (0.238-0.341) for non-carcinogenic risk assessment were below 1, implying no significant non-carcinogenic risk health impact in accordance with USEPA (U.S. Environmental Protection Agency) standard. With the exception of chromium (3.514 x 10⁻³ to 4.715 x 10⁻³), the carcinogenic risk assessment showed that the cancer risk from these metals at all stations was within the permissible range of 1.0 x 10⁻⁶ to 1.0 x 10⁻⁴. The incremental lifetime cancer risk (ILCR) from Cr VI ingestion across all stations warrants further consideration.

Article History

Received: Sep 21, 2025; Accepted: Mar 22, 2026; Published: June 30, 2026.

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