Groundwater Quality Assessment for Drinking Water using Water Quality Index (WQI): A Case Study of Eastern Obolo, Southeastern Nigeria

Abstract

Groundwater, an important source of drinking water for coastal communities of the world including Eastern Obolo, South eastern Nigeria has been adversely affected by both natural and anthropogenic activities. Understanding the quality of this resource for proper management is pertinent. Consequently, this project aims at assessing the groundwater quality of the study area using Water Quality Index (WQI). Eleven (11) groundwater samples from different locations were collected in 120ml plastic bottles and transported to the laboratory for analyses.  Physiochemical and chemical analysis including EC, TDS, temperature, pH, Ca²⁺, Mg²⁺, K⁺, Na⁺, Mn²⁺, Fe²⁺, NH₄⁺, PO₄^-, NO₃^-, NO₂^-, Cl^-, F^-, SO₄^2-, HCO₃^2- were analysed for in the water samples. The result of the physicochemical analysis reveals that the groundwater in the area is slightly acidic to alkaline. The chemical analysis result showed concentration of major cations and anions in order of Fe²⁺> Mg²⁺> Na⁺> Ca²⁺> Mn²⁺> K and Cl^-> HCO₃^-> NO₃^-> NO₂^-> F^-> SO₄^2-> PO₄^2- respectively. The dominant hydrochemical facies in the study area are; Ca-Mg-Cl-HCO₃^-, and Na+K-Cl-HCO₃^- with Na+K-Cl as minor water type. The Water Quality Index (WQI) for the different samples in the study area range from 191.2171 to 1309.489. The Index reveals that the groundwater in this area has poor water quality and are unsuitable for drinking purposes. Hence, treatment before consumption due to high concentration of chloride, bicarbonates, magnesium, iron and manganese is recommended.

Keywords: Water Quality Index, Eastern Obolo, Coastal Region