Hydrogeochemical Characterisation and Assessment of Mineral–water Interaction in Aquifer Systems of the Niger Delta, Nigeria

Abstract

Groundwater is an important source of water supply in the Niger Delta, and its chemistry reflects interactions between recharge water and aquifer materials. This study characterised the hydrogeochemistry of selected Niger Delta aquifer systems and assessed mineral–water interaction processes using physicochemical parameters, major dissolved ions and diagnostic ionic relationships. Groundwater was sampled from ten boreholes representing different hydrogeological settings. The samples were analysed for pH, electrical conductivity, total dissolved solids, hardness, . Groundwater pH ranged from 5.82 to 7.21, indicating slightly acidic to neutral conditions, while electrical conductivity ranged from 186 to 842 µS/cm and total dissolved solids from 121 to 548 mg/L. Sodium and calcium were the principal cations, whereas bicarbonate and chloride were the dominant anions. Higher dissolved-ion concentrations and hardness at selected locations indicated greater mineralisation, whereas lower values at other locations suggested comparatively dilute groundwater. The combined hydrochemical evidence indicates that mineral dissolution, silicate weathering and cation exchange contribute to groundwater evolution, with localised chloride enrichment at some sampling locations. Overall, the groundwater chemistry reflects spatially variable interaction between recharge water, aquifer materials and groundwater flow. These findings provide a hydrogeochemical basis for interpreting groundwater quality and supporting groundwater-resource assessment in the Niger Delta.