Odosa OTUBU

The indiscriminate disposal of solid waste and the proliferation of open dumpsites pose serious threats to soil quality, groundwater integrity and plant health. This study evaluated the ecological risk associated with heavy metals in soils collected around open dumpsites in Oluku, Benin City, Edo State, Nigeria. Ten soil samples were randomly collected using an auger and analyzed for heavy metal concentrations using Atomic Absorption Spectrophotometry (AAS). The mean concentrations of the analyzed metals ranged from 1.22 mg/kg for Cu to 3.05 mg/kg for Mn, following the decreasing order: Mn > Cd > Pb > Cr > Ni > Co > Zn > Fe > Cu. The contamination factor (CF) values for Fe, Zn, Cu, Pb, Cd, Mn, Ni, Cr and Co were 1.23, 1.26, 1.22, 1.95, 2.48, 3.05, 1.36, 1.42 and 1.29, respectively, indicating moderate contamination by Cd and considerable contamination by Mn. The ecological risk factor (Eir) of individual metals revealed that Cd (mean = 74.4) contributed the highest ecological risk, followed by Mn (30.58) and Pb (9.77). The overall potential ecological risk index (RI) was 133.92, suggesting a moderate level of ecological risk in the study area. The findings imply that uncontrolled dumping and anthropogenic activities contribute significantly to the accumulation of toxic metals in the soil, which may pose long-term environmental and health risks. Proper waste management strategies and periodic monitoring of soil quality are therefore recommended to mitigate further contamination and safeguard environmental health.