Piper Trilinear and Gibbs Description of Groundwater Chemistry in Port Harcourt, Nigeria

Abstract

Several studies have shown that there are high salinity values in the groundwater quality in certain areas within Port Harcourt city. However, a detailed investigation on the cause is not yet documented hence, this research investigated the factors governing the hydro-geochemistry of the said area. This was achieved by analysing concentrations of 7 ions (both cations and anions) and total dissolved solids (TDS) in water samples obtained from 26 drilled boreholes and 4 hand dug wells, evenly distributed within the study area. The examined ions are Ca²⁺, Mg²⁺, Na⁺, K⁺, Cl^-, HCO₃^- and SO₄^2-. Laboratory results were plotted on Piper trilinear and Gibbs diagrams through Aquachem 5.1 software package and it was revealed that 63.33% of the total samples fell in Na-Cl hydrochemical facies while the remaining 36.67% occurred in Ca-Cl facies. It was also revealed that the controlling factors for formation of the analysed ions were precipitation and rock weathering on 76.67% and 23.33% respectively. Hence, it was concluded that Na-Cl facies is the dominance hydrochemical facies in the study area while the main factor governing the formation of ions is precipitation. However, it was recommended that the rate of pumping out water from wells in certain parts of the study area should be reduced in other to avoid seawater intrusion.