Hydrochemistry and Water Quality Index of groundwater resources in Enugu north district, Enugu, Nigeria.

The physicochemical parameters of groundwater in 12 cluster boreholes in Enugu North district/region, southeast Nigeria, were studied. Twelve physicochemical parameters were determined in triplicates at monthly intervals for 3 months in dry season and then repeated in rainy season in 120 boreholes grouped into 12 clusters for 2 years. The range of values obtained during dry season include phosphate (0.12-0.87 mg/L), nitrate (1.24-8.72 mg/L), sulfate (20.10-24.34 mg/L), pH (4.9-7.5), E.C. (10.0-410.0 μS/cm), total acidity (0.06-1.24 mg/L), total alkalinity (28.0-22.10 mg/L), total hardness (100.0-140.1 mg/L), TSS (70.0-270.0 mg/L), TDS (0.00-210.0 mg/L), TS (70.0-390.0 mg/L), and turbidity (3.4-50.0 mg/L) while rainy season values were phosphate (0.30-10.60 mg/L), nitrate (1.20-120.0 mg/L), sulfate (0.0-100.0 mg/L), pH (4.9-7.5), E.C. (10.0-360.0 μS/cm), total acidity (0.10-10.5 mg/L), total alkalinity (10.0-52.1 mg/L), total hardness (100-130 mg/L), TSS (100.0-280.0 mg/L), TDS (0.0-260.0 mg/L), TS (110.0-560.0 mg/L), and turbidity (3.80-56.0 mg/L). When compared with standard guideline values recommended by regulatory bodies, rainy season nitrate values in some samples and phosphate mean values were higher than recommended values. Seasonal variations of the parameters in the samples were observed. Statistical analysis showed statistically significant variations between the 12 borehole water physicochemical parameters in dry and rainy seasons. Water quality index (WQI) analysis categorized all the water samples within the range of good to excellent.