Assessment of Groundwater Quality of Ilorin Metropolis using Water Quality Index Approach

Abstract

Groundwater as a source of potable water is becoming more important in Nigeria. Therefore, the need to ascertain the continuing potability of the sources cannot be over emphasised. This study is aimed at assessing the quality of selected groundwater samples from Ilorin metropolis, Nigeria, using the water quality index (WQI) method. Twenty two water samples were collected, 10 samples from boreholes and 12 samples from hand dug wells. All these were analysed for their physico – chemical properties. The parameters used for calculating the water quality index include the following: pH, total hardness, total dissolved solid, calcium, fluoride, iron, potassium, sulphate, nitrate and carbonate. The water quality index for the twenty two samples ranged from 0.66 to 756.02 with an average of 80.77. Two of the samples exceeded 100, which is the upper limit for safe drinking water. The high values of WQI from the sampling locations are observed to be due to higher values of iron and fluoride. This study reveals that the investigated groundwaters are mostly potable and can be consumed without treatment. Nonetheless, the sources identified to be unsafe should be treated before consumption.KEYWORDS: groundwater, water quality index, potability, physico - chemical, parameter