AN ANALYSIS OF SPATIAL VARIATION OF GROUNDWATER QUALITYIN FEDERAL CAPITAL TERRITORY NIGERIA

ABSTRACT:This study was carried out to determine the spatial variation of groundwater qualityin Federal Capital Territory, Nigeria, acrossthe major lithological regions which include: the older granite, the migmatite gneiss complex, and the metasediment.Fifteen (15) groundwater samples (Borehole and well water)were collected for two years (2019 and 2020)using stratified sampling technique; five (5) samples from each lithological unitfor physico-chemical analysis which include; pH, Temperature, Electrical Conductivity (EC), Turbidity, Dissolved Oxygen (DO), Nitrate, Total Dissolved Solids (TDS), Colour, Total Alkalinity, Total Harness, Calcium, Magnesium, Copper, Iron, and Bicarbonate, with mean values ranging from 3.51 - 6.58, 17.0 - 22.20C, 13.4 - 842uS/cm, 0.63 - 32.6NTU, 5.46 - 8.82mg/l, 0.5 - 26.0mg/l, 13.1 - 591.0mg/l, 71.2 - 178mg/l, 17.8 -285.0mg/l, 13.0 - 282.0mg/l, 0.7 - 10.0mg/l, 0.02 - 0.34mg/l, 0.08 - 0.32mg/l, 7.48 - 306.2mg/l respectively. The physico-chemical parameters were all determined according to procedures outlined in the Standard Methods for the Examination of water and Wastewater (APHA, 2012) and the result revealed that all the physico-chemical parameters from the different lithological regions were within the World Health Organization (WHO) standards and Nigerian Standards for Drinking Water Quality (NSDWQ) guidelines, except for pH which had values below the standards set by both WHO and NSDWQ at 6.5-8.5. There was also elevated concentrations of nitrate recorded in two samples (HDW1 and HDW2). However, there were wide variations in the concentration of all the physicochemical attributes of the groundwater across the three major lithological regions. The result of the inferential statistics carried out using ANOVA showed that there was no significant variations in the physiochemical attributes of groundwater quality between the three major lithological regions. It was recommended therefore that that there should be further study and constant monitoring of groundwater in the study area, as the quality of the groundwater changes with time, especially in areas where there is incessant anthropogenic (human)activities.

0 08 Feb, 2022

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