Hydrochemical Characterization of Groundwater of Chanchaga and Its Environ, Minna North Central Nigeria

Abstract

This research study focuses on hydro-geochemistry of Chanchaga area which is an integral part of Minna North Central, Nigeria. The area is underlain by the Precambrian Basement Complex such as Schist, Migmatite Gneiss and Granites. These rocks are dominantly structured in NE – SW and N – S directions. These structures have effect on both surface drainage pattern and influence the groundwater flow directions. The Hydrogeological mapping entailed the measurement of groundwater table of hand-dug wells and subsequent sampling exercises. Twenty one (21) water samples were taken for physicchemical analysis from both hand-dug wells and hand pump bore holes including one sample from Bosso dam for standard laboratory analysis at the Federal Ministry of Agriculture, Water Quality Laboratory, Minna-Niger State. The chemical analysis revealed the concentrations of hydrochemical parameters in the following range order: Temperature (28.1 – 31.3 °C), TDS (0.06 – 0.47ppm), Electrical conductivity (0.01 – 0.96 µs/cm), pH (5.55 – 7.2), salinity (1.1 – 1.9Mg/l), Turbidity (0.8 – 37NTU), Na+ (19.74 – 92.8Mg/l), K+ (0.94 – 54.4Mg/l), Ca2+ (8.02 – 92.8Mg/l), Mg2+ (0.49 – 55.6Mg/l), Cl- (11 – 156Mg/l), SO4 (0 – 69Mg/l), HCO3 (0 – 429Mg/l), CO4 (0 – 98Mg/l), Cu2+(0 – 13.9Mg/l) and Fe2+ (0 – 2.6Mg/l). From parametric comparism with WHO standards all the parameters under considerations fall below the maximum permissible limit except some very few parameters that revealed maximum concentration slightly higher to the recommended limits in some of the area. From correlation matrix Na+ shows positive significant correlation between TDS, Cl-, and SO4 (r = 0.542, 0.698, 0.594) respectively, which suggest that the aquifer chemistry is control by those elemental constituents. In the same vein Mg2+ depict significant positive correlation between Cl- and SO4 (r = 0.586 and 0.461). Piper diagram revealed three different facies which can be grouped into two zones: Earth alkali freshwater and area of alkali freshwater, it can be subdivided into bicarbonate type of water and sulphate type including sulphate-chloride type. The presence of bicarbonate in the water indicates that the twenty one wells were variously sunk in Calcium bearing granite gneiss while the Carbonates are the products of reaction between Carbon dioxide and rain water. Also some location has sulphate – Chloride type which might be the resultant influence of the pollution from municipal water and waste products. Despite the low-medium enrichment of the ionic parameters present in the groundwater of the study area, still there is need for further treatment before use especially for domestic purposes.