Evaluation of heavy metal contamination and associated health risks in dumpsites soils of Idah and Igalamela/Odolu in Kogi State, Northcentral, Nigeria.

Abstract

This study assessed the concentration and environmental implications of heavy metals in soils from selected dumpsites in parts of Idah and Igalamela/Odolu in Kogi State, North-Central Nigeria. Twenty soil samples were collected at depths of 10–50 cm from major dumpsites in the study area. The samples were air-dried, digested using aqua regia, and analyzed for lead (Pb), cobalt (Co), nickel (Ni), copper (Cu), manganese (Mn), cadmium (Cd), zinc (Zn), and chromium (Cr) using Atomic Absorption Spectrophotometer (AAS). The measured concentrations were compared with WHO/DUTCH permissible limits to evaluate contamination levels and potential risks. Results revealed that Pb (12.413–150.761 mg/kg), Mn (0.121–3.423 mg/kg), Cd (0.002–14.463 mg/kg), and Zn (1.875–126.795 mg/kg) recorded average concentrations above recommended limits, indicating substantial contamination. Although Co, Ni, Cu, and Cr showed mean values below permissible limits, elevated concentrations were observed at specific locations, suggesting localized pollution hotspots. The order of metal abundance was Cd > Mn > Zn > Pb > Cr > Ni > Cu > Co, reflecting the dominance of toxic metals in the studied soils. The elevated heavy metal levels were primarily attributed to anthropogenic activities such as improper waste disposal, vehicular emissions, and dumping of agricultural and industrial residues. The findings highlight significant ecological and public health concerns, particularly due to the cultivation of edible crops on these contaminated soils. This study underscores the urgent need for continuous monitoring, improved waste management practices, and remediation strategies to mitigate soil degradation and safeguard human health in the study area.