Metallic Constituents, Human Cancer Risk Assessment, and Allium Cepa Genotoxicity Bioassay of a Municipal Dumpsite Soil and Simulated Leachate in Anyigba, Kogi State, Nigeria
DOI:
https://doi.org/10.33003/fjs-2026-1022-6196Keywords:
Dumpsite, heavy metals, health risk, hazard, Allium cepa, genotoxicity, AnyigbaAbstract
This study investigated heavy metal contamination in soil from the Anyigba municipal dumpsite, located within Anyigba Main Market, Kogi State, Nigeria, and assessed associated human health risks and plant-based cytogenotoxicity. Composite soil samples were collected using grid sampling, while simulated leachate was prepared through aqueous extraction. Fifteen metals were analysed using inductively coupled plasma optical emission spectrometry (ICP-OES). Human health risks were evaluated using the Hazard Quotient (HQ), Hazard Index (HI), and Lifetime Cancer Risk (LCR) for ingestion, inhalation, and dermal exposure among children and adults, following the USEPA framework. Leachate cytogenotoxicity was assessed using the Allium cepa root tip assay at 20, 40, and 60% concentrations. Iron (97.42 mg/kg), manganese (66.04 mg/kg), zinc (42.84 mg/kg), silver (31.71 mg/kg), and copper (13.39 mg/kg) were the predominant soil metals. Copper, zinc, iron, manganese, and chromium exceeded permissible limits in both soil and leachate. Children exhibited HI values above unity for manganese (6.73), copper (4.72), iron (3.02), and zinc (2.26), primarily through ingestion, whereas adult HI values remained below 1.0. Chromium presented unacceptable cancer risks for children (TLCR = 7.23 × 10⁻⁴) and adults (TLCR = 1.06 × 10⁻⁴). The Allium cepa assay revealed concentration-dependent toxicity, with root growth inhibition reaching 92.73% and mitotic index decreasing from 11.75% in controls to 2.25% at 60% leachate concentration. These findings identify the dumpsite as a potential source of significant environmental contamination and human health risks, particularly for children, highlighting the urgent need for remediation and effective environmental regulatory enforcement.
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Copyright (c) 2026 Andrew Omachoko Onoja, Patience Omojo Ejembi, Dangana Elizabeth Ojochebo, Azeez Zainab, Momoh Theophilus Boniface
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