Hydrogeochemical Assessment of Groundwater Quality in Makarfi and Environs, Kaduna State, Nigeria

Abstract

Groundwater serves as a vital and often primary source of drinking and domestic water, particularly in the rural areas of northwestern Nigeria. Despite its critical importance, the quality of this essential resource is frequently inadequately characterized. This study undertakes a comprehensive assessment of the hydrogeochemical characteristics and overall groundwater quality within Makarfi and its surrounding areas in Kaduna State. To achieve this, five (5) groundwater samples were systematically collected from both hand-pump boreholes and open wells. These samples were subsequently subjected to rigorous analysis for various physicochemical parameters, a suite of selected major ions (Na+, K+, NO3-, SO42-, HCO3-, Cl-), and crucially, potentially hazardous heavy metals (Pb2+, As3+). The Analytical results revealed that the concentrations of most major ions were generally within the permissible limits established by the World Health Organization (WHO) for drinking water. Specifically, sodium concentrations ranged from 9.2 to 32.0 mg/L, potassium from 2.5 to 9.1 mg/L, nitrate from 0.007 to 0.025 mg/L, and chloride from 0.7 to 3.0 mg/L. However, a significant concern emerged regarding the heavy metals: Lead (Pb2+) concentrations, ranging from 0.023 to 0.922 mg/L, and Arsenic (As3+) concentrations, ranging from 0.017 to 0.077 mg/L, consistently exceeded the WHO permissible limits in the majority of the analyzed samples. This alarming finding strongly indicates potential health risks for the local population relying on these water sources. The hydrogeological context of the study area indicates that groundwater occurrence is predominantly controlled by the weathered and fractured basement rocks, which include coarse-grained granite, migmatite gneiss, and laterite. Furthermore, the hydrogeochemical facies analysis identified the water as predominantly Na-HCO3 and NaCl types, suggesting that rock weathering and precipitation are the primary controlling factors influencing the groundwater chemistry. Based on these findings, the study strongly recommends regular monitoring of groundwater quality and the implementation of appropriate treatment measures before consumption to safeguard public health.