Hydrogeochemical Assessment of Mbanabor Area, Anambra Basin, Southeastern Nigeria

Abstract

Surface and groundwater resources evaluation of Mbanabor was done to assess the quality for human consumption and agricultural purposes. This was achieved through physicochemical and bacteriological analysis of twenty one (21) water samples from both surface and groundwater sources in the area. The result reveals that the concentration of Ca²⁺(mg/l), Mg²⁺(mg/l), Na⁺(mg/l), K⁺(mg/l), Fe²⁺(mg/l), Pb²⁺(mg/l), Cd²⁺(mg/l), Zn²⁺(mg/l), and Cu⁺(mg/l), range between: 0.12 – 27.21, 0.05 – 3, 3.23 – 7.06, 0.1 – 7.31, 0.05 – 3.62, 0.002 – 0.28, 0 – 0.02, 0.04 – 2.5 and 0.001 – 3.0 respectively. The range of SO₄^2- (mg/l), NO₃^- (mg/l), and HCO₃^- (mg/l), are between: 1.0 – 13.1, 0.27 – 49.0 and 8.00 – 20.5 respectively. The average of pH (mg/l), colour (Hz), temperature (⁰C), conductivity (us/cm), turbidity (NTU), TDS (mg/l), TSS (mg/l), BOD (mg/l), DO (mg/l) and hardness (mg/l), are: 6.19, 61.43, 24.7, 63.57, 4.48, 21.44, 5.05, 0.69, 4.64 and 6.4 respectively. Classification of the water samples shows the predominance of Ca(Mg)Cl(SO₄) and Na(K)Cl(SO₄) water types that are largely soft. The values of the Sodium Adsorption Ratio (SAR) range between 0.24 – 2.86 indicating prevalence of good water for agricultural uses. The surface water sources are predominantly infected with microbial contamination, indicating significant input of organic (Faecal) wastes in the flow system. Water resources development programmes in the area requires elaborate qualitative assessment, to ensure that any necessary pre-use treatment is effected.

Keywords: Water Quality, Water Classification, Hydrogeochemistry, Sodium Adsorption Ratio.