Characterization of factors influencing water quality in Federal University of Agriculture Abeokuta and its Environ, Southwestern Nigeria

Quality of water is as important as its quantity, because it determines the state of health of man to a large extent. To maintain sustainable human development and public health of students’ community, water quality assessment was conducted by characterizing the influence of anthropogenic and natural processes on thirty-one (31) water samples from boreholes, hand-dug wells and surface water from Federal University of Agriculture Abeokuta and its environs. Physico-chemical data, statistical data, ionic-ratios, Gibb’s plot etc. were employed in delineating dissolved ions’ sources in the water from the study-area. Some physicochemical parameters were determined insitu with a potable multimeter, while the others were determined in the laboratory using standard methods. Various ionic plots showed that both carbonate dissolution and silicate weathering were the major contributors of ions in the water samples. Chloro-Alkaline Indices 1 and 2 values of samples collected were positive indicating direct ion exchange predominance. Factor analysis produced three factors accounting for 76% of the total variance. Factor-1 had high loadings (45.9%) on calcium, magnesium, bicarbonate, sulphate, potassium, pH, electrical conductivity and total dissolve solids suggesting water–rock interaction within the aquifer as the primary influence on groundwater quality and a common geogenic source. This was also corroborated by Gibb’s plot. Factors 2 and 3 revealed a moderate-high loading on NO3−, Cl− and pH suggesting that anthropogenic activities influence on water quality was quite significant especially in shallow and uncovered wells and surface water but minimal in borehole samples. Due to intense anthropogenic activities (farming and septic tank placement) and poor well management (open wells, poorly completed wells), groundwater drawn from shallower wells and surface-water appeared to be more polluted compared to those from boreholes. Generally, groundwater quality ranged from fairly to well suitable for drinking purpose except in shallow and poorly constructed hand-dug wells bordering farm areas.