Groundwater is required for continuity of life and sustainability of ecosystem. Hence, this study
aimed at assessing the groundwater quality in Abeokuta with respect to drinking and irrigation uses. In-situ
parameters (pH, EC, Temperature and TDS) were measured using a multiparameter portable meter (model
Testr-35). Major cations-trace metals and anions were subsequently determined in the laboratory using ICPMS
and titration methods respectively. Bacteriological analysis was carried out using Nutrient agar
medium.Electrical conductivity, pH and TDS had average concentrations of 504.9µS/cm, 6.5 and 379mg/L, Ca,
Mg, Na and K had average concentrations in mg/L of 30.5, 8.83, 46.65 and 11.78 while HCO3, SO4, Cl and NO3
average concentrations in mg/L were 99.8, 40.3, 61.3, and 13.7 respectively. Trace metals; Al, Si, Fe and Mn
average concentrations in mg/L were 0.37, 21.98, 24.3 and 0.07 while those of Li, Cu, Pb, Co, Cd and As in
µg/L were 11.69, 3.50, 2.95, 0.98, 0.52 and 0.78 respectively. Total Bacteria Count (TBC) that ranged from 2 to
190cfu/100ml and coliform count from 1 to 120cfu/100ml had high positive correlation with NO3 indicating
similar source possibly from waste/faeces dumps. The concentrations of ions in the groundwater fell within
acceptable limits of both WHO and NAFDAC standards. Estimated water quality index revealed that 22% of the
water samples fell in good water quality category while 72.2% and 5.5% were in the medium and bad water
quality categories respectively.This study has revealed the effectiveness of hydrochemical and bacteriological
evaluations in groundwater quality assessment. Groundwater in the study area was not potable but had good
irrigation quality.