Assessment of Heavy Metal Contamination in Soils of Gashaka Local Government Area, Nigeria Using Geo-Accumulation Index

Abstract

Anthropogenic activities such as mining, improper waste disposal, and agricultural practices have contributed significantly to heavy metal contamination in soils, posing substantial ecological and public health risks. This study assessed the levels of heavy metal contamination in soils across four locations: Lambangudu, Maijankasa, Gidan Kara Bodel, and Quentin Gate in Gashaka Local Government Area (LGA), Taraba State, Nigeria. Using the Geo-accumulation Index (Igeo), soil samples were analysed for nine heavy metals: cadmium (Cd), lead (Pb), cobalt (Co), copper (Cu), chromium (Cr), zinc (Zn), nickel (Ni), manganese (Mn), and iron (Fe). The results revealed that Mn, Pb, and Fe exhibited extreme contamination (Igeo > 6) across all sites, indicating strong anthropogenic influence, likely from artisanal mining and unregulated waste disposal. Ni and Co also recorded high contamination levels, falling within the heavily to extremely contaminated class (Igeo Class 5), while Zn showed moderate contamination. Cd, Cu, and Cr remained within uncontaminated levels (Igeo Class 0), suggesting limited anthropogenic inputs for these metals. The findings highlight serious ecological threats and potential public health hazards due to the bioaccumulative nature of these metals. Urgent remediation, policy enforcement, and public health interventions are recommended to mitigate the risks in these vulnerable communities.