SEASONAL CHARACTERIZATION OF GROUNDWATER QUALITY IN MINNA METROPOLIS USING WATER QUALITY INDEX

Abstract

This study is aimed at assessing and characterization of groundwater seasonally in Minna metropolis using water quality index (WQI) with the aid of weighted arithmetic index method. 90 groundwater samples from four sub-areas within Minna metropolis were collected and subjected to comprehensive physicochemical analyses during dry and wet seasons. Parameters considered included pH, total hardness, calcium, magnesium, bicarbonate, chloride, nitrate, sulphate, total dissolved solids, iron, manganese and fluorides. Correlation analysis was used to check the relationships among all the parameters for both the dry and wet seasons. In all the study areas, the WQI of the samples ranged from 334.27 to 535.88 and 242.51 to 404.19 in both dry and wet seasons respectively which has been attributed to the higher values of Manganese, sulphate, total hardness, total alkalinity, and particularly total dissolved solids in the groundwater. Significant correlation was observed in all sampling areas between electrical conductivity, chloride, magnesium, sodium, and total hardness at 0.01 level and with manganese at 0.05 level. The analysis of the results showed non-compliance with World Health Organization (WHO) and Nigerian Industrial Standard (NIS) standards which reveals that the groundwater of the study areas is not safe for consumption and therefore needs serious degree of treatment before consumption. This present study thus suggests the use of water quality index as a very helpful tool that will enable the public and stakeholders to evaluate the quality of groundwater.