DOI: 10.11648/j.ajese.20261002.13 ISSN: 2578-7993

GIS-Based Assessment of Soil Heavy Metal Contamination in Asa Dam Industrial Area Ilorin, Nigeria

Isiaka Alage, Ebeiyamba Ekpo, Seyi Olatoyinbo, Ojo Gbenga
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Industrial activities are among the major sources of heavy metal accumulation in soils, posing significant threats to environmental quality, ecosystem stability, and public health due to the persistence and bioaccumulative nature of toxic metals. Among these pollutants, lead (Pb) and cadmium (Cd) are widely recognized as critical indicators of industrial contamination because of their potential mobility through soil–water–plant systems and subsequent entry into the food chain. In response to increasing industrialization around the Asa Dam area in Ilorin, Kwara State, Nigeria, this study evaluated the spatial distribution and concentration of Pb and Cd in soils within selected industrial zones. A total of ten soil samples were systematically collected from each industrial site at a depth of 20 cm during the wet season, and sampling locations were georeferenced using a Garmin Global Positioning System (GPS) receiver. The concentrations of Pb and Cd were determined using Atomic Absorption Spectrophotometry (AAS), while spatial distribution patterns were analyzed and mapped using the Inverse Distance Weighting (IDW) interpolation technique within a Geographic Information System (GIS) environment. The results showed that the concentrations of Pb and Cd across all sampled locations remained below the permissible limits recommended by the World Health Organization (WHO). Comparatively higher concentrations were observed around KAM Industries relative to Doyin Investments, although these values were still within acceptable environmental thresholds. The spatial distribution maps further indicated localized variations in heavy metal concentrations without evidence of severe contamination hotspots. Overall, the findings suggest that soils within the Asa Dam industrial corridor are presently not significantly contaminated by Pb and Cd and therefore pose minimal immediate ecological and human health risks. Nevertheless, continuous environmental monitoring is recommended to ensure early detection of potential future contamination associated with ongoing industrial expansion in the area.

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