Groundwater quality and its suitability for domestic and agricultural uses in Wilberforce island, southern Nigeria

Abstract

Hydrogeochemical analysis of groundwater samples collected from parts of the Wilberforce Island in Bayelsa State, Southern Nigeria has been carried out in an attempt to assess the suitability of the groundwater for domestic and agricultural purposes in the area. The study was based on thirteen groundwater samples collected from domestic boreholes analysed for some physical and chemical constituents including electrical conductance, pH, total dissolved solids (TDS), alkalinity, hardness, Na⁺, K⁺, Ca²⁺, Mg²⁺, Fe, Cl^-, SO₄^2-, NO^-₃, and HCO₃. The quality of the groundwater samples was evaluated with reference to WHO standards. The results obtained showed that the concentration of dissolved major cations and anions in the groundwater vary spatially and mass abundance was in the order of: Ca²⁺ > Na⁺ > Fe >K⁺ > Mg²⁺ for cations and Cl^- > HCO₃ ^- > CO₃ ^- -> NO₃ ^- > SO₄^2-for anions. The concentration of these ions as well as such parameters as total hardness and TDS are below the World Health Organisation (WHO) standard for domestic uses of water in over 80% of the samples. However, iron was over 3000% higher than the WHO permissible limits. The groundwater in the area is fresh, high salinity and low sodium in nature. Ca^– HCO₃ and Ca– Cl– HCO₃ are the dominant hydrochemical facies of the study area. Alkali earths metals (Ca²⁺ and Mg²⁺) and strong acids (Cl^- and SO4^2-) are slightly dominating over the alkali metals (Na⁺ and K⁺) and weak acid anions (HCO₃^- and CO₃^2-).

KEYWORDS: Groundwater quality, hydrogeochemical, sodium percent, sodium adsorption ratio, Wilberforce Island