Ecological Risk Evaluation of Heavy Metal Contamination in Soil Due to Abattoir Activities in Akinyele, Oyo State, Nigeria

Various organs of cattle have been found to contain heavy metals, and most abattoirs in Nigeria lack or have inadequate waste management methods. Soil samples were collected from both Akinyele abattoir in Oyo State to determine the presence of heavy metals using Atomic Absorption Spectrophotometry (AAS - model 210/211 VGP). Lead (Pb) concentrations were higher in Sample 1 (5.8 ± 0.4 mg/kg) than in Sample 2 (2.6 ± 0.2 mg/kg), indicating pollution from industrial and slaughterhouse waste. Levels of Cadmium (Cd), Chromium (Cr), Zinc (Zn), and Copper (Cu) were also consistently higher in Sample 1 compared to Sample 2, with Cd at 1.4 ± 0.1 mg/kg versus 0.6 ± 0.1 mg/kg, Cr at 3.7 ± 0.2 mg/kg versus 1.8 ± 0.1 mg/kg, Zn at 112.4 ± 5.7 mg/kg versus 79.2 ± 3.9 mg/kg, and Cu at 34.5 ± 2.3 mg/kg versus 21.7 ± 1.5 mg/kg. The contamination factor (CF) for all heavy metals exceeded their respective background levels; Cd (2800) and Cu (434) had the highest and lowest values, respectively. The overall Pollution Load Index (PLI) was much higher for sample 1 (499.42) than for sample 2 (264.19). The total Ecological Risk Index (ERI) for sample 1 was 42,757.59, and for sample 2, 47,625.56, indicating a greater overall ecological risk and emphasising the need for proper treatment of abattoir waste before disposal to prevent environmental imbalance and loss of biodiversity.