Assessment of sub-surface water corrosion and encrustation potentials in parts of Eastern Dahomey Basin, Southwestern Nigeria

Understanding hydro-geochemical parameters and corrosion-encrustation tendencies in coastal aquifers is crucial for sustainable water quality management. In the eastern Dahomey Basin of southwestern Nigeria, rapid deterioration of metal pipes, surface tanks, and boreholes has been observed, leading to significant infrastructure damage and failure. This study evaluates groundwater quality and assesses corrosion and encrustation potentials using multiple geochemical indices. Twenty groundwater samples were collected and analyzed for physicochemical parameters (pH, Electrical Conductivity (EC), Temperature (°C), Total Dissolved Solids (TDS)) and chemical constituents including hardness, chloride, manganese, and iron using Atomic Absorption Spectrophotometry (AAS) and titration. Physicochemical and ions concentration analysis results were further adopted to compute corrosion and encrustation indices including; Langelier Index (LSI), Ryznar Stability Index (RSI), Larson-Skold Index (LS), and Aggressive Index (AI) were computed. Results indicate LSI values of the samples were corrosive while they exhibited higher scaling tendency. AI indicated moderately corrosive and scaling-prone; RSI results ranging from high corrosive to severely corrosive nature; LS indicated high concentration scaling-prone with mild corrosive status. Spatial analysis revealed higher corrosion tendencies near coastal zones due to seawater intrusion influences. The study highlights the need for corrosion-resistant materials and preventive measures in groundwater infrastructure development.