Geochemical assessment of groundwater pollution from sewage effluents in the University Campus of Ibadan, southwestern Nigeria

Abstract

Sewage effluent is often rich in toxic constituents leading to environmental hazard. Continuous discharge of sewage effluents into an agricultural training farm in University of Ibadan is polluting groundwater used for cultivation of vegetables and cereals, as also for drinking, thus posing risk to human health. The study area is underlain by Precambrian banded gneisses. The study is based on seven groundwater samples and twenty-three soil samples collected from seven trial pits. The samples have been analysed using AtomicAbsorption Spectrophotometric and Inductively Coupled Plasma- Emission Spectroscopy respectively.Water analyses data show that the concentrations of Fe, Pb and Cd have exceeded the WHO (2006) drinking-water quality guidelines. Correlation coefficient of water shows that the coefficient corresponding to zero has a percentage of 29, whereas 71 % of correlation is either from the same source or from different source of enrichment. The correlation analysis of soil samples shows that 92.9% of the elements have the same source. The enrichment factor and geo-accumulation analyses confirm enrichment of Cu, Cd, Fe, Pb, Zn, Sr, Ba, Mn, Ni and La concentrations contributing to the pollution. All the metals analysed in the soil sample from the farm have anthropogenic influence.