Evaluation of Groundwater Quality for Drinking Purposes using Water Quality Index, in Keffi Central Town of Nasarawa State

Abstract

In Nigeria, access to fresh drinking water has become serious challenges to both rural and urban areas.The aim of this study was to evaluate groundwater quality in Keffi central town of Nasarawa State for drinking purposes using the water quality index technique. Eight groundwater samples (four from both boreholes and dug wells) were collected from the study areaduring the wet season in October 2019. The water quality index is a mathematical method used to facilitate water quality explanation. The pH, Electric Conductivity, Total Dissolved Solids, Total Hardness, Calcium, Magnesium, Sodium, Chloride, Sulphate and Bicarbonate were determined according to standard methods. pH ranged from 5.7 to 7.1(mg/l), Electric conductivity ranged from 256 to 1591(µs/cm), Magnesium ranged from 2.6 to 29(mg/l), Calcium ranged from 3.7 to 34(mg/l), Sodium ranged from 22 to 56(mg/l), Chloride ranged from 8.4 to 63(mg/l), Bicarbonate ranged from 54.3 to 219.6(mg/l), Sulphate ranged from 0.1 to 32.4(mg/l), Total Dissolved Solids ranged from 95.2 to 302.94(mg/l) and Total Hardness ranged from 23.8 to 204.23(mg/l). The water quality index obtained from different locations was found to vary from 44.32 to 61.60 for boreholes and 72.55 to 97.77 for dug wells. The results for the water quality index indicated that borehole locations 2, 4, and 8were safe for human consumption, while dug well locations 3,5,6 and 7were not suitable for drinking purposes, compared with Nigerian industrial standard drinking water. The reasons for the high water quality index values of some study areas were attributed to the lithological variation and anthropogenic activities in the region. Therefore, some of the well water required treatment such as demineralization.