Ionic Ratios and Geochemical Characterization of Groundwater System in Parts of Port Harcourt, Nigeria

T. C. Dikeogu¹, J. I. Onyewudiala², A. C. C.Ezeabasili³, O.N.K. Swift⁴

^1,Department of Geosciences, Federal University of Technology, P.M.B. 1526,Owerri, Nigeria

²Department of Mechanical Engineering Federal University of Technology Owerri

⁴Anambra State University Uli

*Corresponding author. E-mail address: dikeogut@yahoo.comonyewudialajulius@yahoo.com, accezeabasili@yahoo.com

Tel: +2348060114036, +2348063314201

Accepted 16 December 2013

Abstract

Geochemical processes of aquifer systems in Port Harcourt were investigated using hydrochemicalfacies and ionic ratios determined using hydrogeochemical analysis of groundwater samples collected from ten (10) representative boreholes.  Emphasis were placed on Electrical Conductivity, P^H, and major ion concentrations such as Ca, Mg, Na, K, Cl, HCO₃ and SO₄. Results of the analysis show that the concentrations of these cations and anions in the groundwater system exhibit spatial and temporal variations. Abundance of these ions is in the following order: Ca> Mg > Na > K >Cl> HCO₃ > SO₄> NO₃. The dominant facies of the area are Ca, Mg, Cl, HCO₃ and Ca, Mg, Cl, SO₄. Carbonate and silicate weathering as well as ion exchange processes are mechanisms controlling groundwater chemistry in the area. Minimal marine influence and low-salt inland waters were inferred on the basis of ionic ratios (Mg/Ca and Cl/HCO₃) and Cationexchange values. Two (2) principal water types; calcium-Magnesium-Chloride-Bicabonate and Calcium-Magnesium-Chloride-Sulphate were delineated.

Keywords:Groundwater, Hydrogeochemistry, Cations, Anions, ionic ratios, Facies