Ecological and human health risk assessments of Potentially Toxic Metals in soils around a private University in Ogun State, Nigeria

Abstract

The environments are polluted with Potentially Toxic Metals (PTMs) due to natural and anthropological activities thereby leading to ecological threats to air, water, soil, plants, animals and humans. This research focuses on ecological and human health risk assessment of potentially toxic metals (Fe, Cr, Cd, Ni and Pb) around a private University in Ogun State. Fifty (50) top soils (0-15cm) were sampled from ten locations within the university. The physicochemical parameters were determined using standard methods, and the concentra-tions of the PTMs were determined using a Flame Atomic Absorption Spectrophotometer (FAAS; Buck Scientific, model 210) after digestion. The results obtained for physicochemical parameters indicated that they were within permissible limits. The mean concentration values of PTMs were: Fe 11805.65±1327.95mg/kg) > Cr (22.89±1.94 mg/kg) > Pb (15.41±1.40 mg/kg) > Ni (1.43±0.67 mg/kg) > Cd (0.04±0.01 mg/kg). The average values of ecological risk for Enrichment Factor, Contamination Factor, Geochemical Index, Pollution Load Index PLI, and Potential Ecological Risk Index are 2.64, 2.69E+01, 1.52E+00, 1.42E-01, and 8.08E+02 respectively. Hazard Quotient (HQ ≤ 1) and Hazard Index (HI ≤ 1) for non-carcinogenic risk suggest that the soils are safe for lifetime exposure. The carcinogenic (10-6 – 10-4) showed an associated risk for both adults and children. The study confirmed that the studied soil sample is pristine and poses neither an ecological nor human health risk. These scientific findings have provided valuable information for making suitable ecological management approaches to ameliorate the influence of potentially toxic metal pollution.

Keywords

• potentially toxic metals
• university
• pollution index
• carcinogenic
• health risk