Authors : Praise Adenike Alli; Samuel Opeyemi Kayode; Oyewumi Tolulope Ajao; Oluwatunmise Peter Abolarin; Joseph Dare Adekunle

Volume/Issue : Volume 11 - 2026, Issue 9 - September

Google Scholar : https://tinyurl.com/yye7ucs8

DOI : https://doi.org/10.38124/ijisrt/26sep070

Note : A published paper may take 4-5 working days from the publication date to appear in PlumX Metrics, Semantic Scholar, and ResearchGate.

Abstract : Freshwater rivers are critical for human livelihoods, agriculture, industry, and ecosystem services, yet they face increasing pressure from urbanization, industrialization, and agricultural runoff. The Ona River in Ibadan, Nigeria, serves multiple domestic, industrial, and ecological functions but is increasingly compromised by anthropogenic inputs, including industrial effluents, untreated sewage, and urban runoff. This study assessed spatio-temporal variations in heavy metal concentrations along the Ona River at three sampling stations during wet and dry seasons. Water samples were analyzed for potentially toxic elements (Fe, Zn, Cu, Cr, As, Cd, Ni, Pb, and Mn) using Atomic Absorption Spectrophotometry, and pollution indices (Geo-accumulation Index, Enrichment Factor, Contamination Factor, Pollution Load Index) and health risk assessments (carcinogenic and non-carcinogenic) were computed. Results indicated seasonal variations, with higher concentrations of Cr, Pb, Cd, and Ni during the dry season exceeding WHO and Nigerian drinking water standards at certain sites. Pollution indices and health risk metrics revealed moderate to high contamination levels, particularly near industrial and urban discharge points. The findings highlight significant ecological and public health risks, emphasizing the urgent need for targeted pollution management strategies to safeguard water quality and community well-being.

Keywords : Ona River, Heavy Metals, Water Quality Assessment, Pollution Indices, Spatio-Temporal Variation, Ecological Risk, Human Health Risk, Urbanization Impact.

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