Hydrochemical Assessment of Groundwater Quality and Seawater Intrusion in the Coastal Aquifers of Limbe, Cameroon: Implications for Industrial Use

Abstract: The increasing dependence on groundwater in coastal urban settings such as Limbe, Cameroon, has raised concerns about seawater intrusion and its impact on water quality. This study investigates the hydro-chemical characteristics of groundwater at New Age found in an industrial estate in the Limbe II Municipality. This estate is located along the Atlantic coast where major industrial activities like the lone oil refinery in Cameroon is found. Twenty-five water samples were collected from November 2020 to May 2021 and assessed for their suitability for industrial use. Multifunctional pocket probes were used for in-situ measurements of temperature, pH, electrical conductivity, and total dissolved solids. Major ions were analyzed using ion chromatography (Metrohm 761 Compact IC), after passing samples through a 0.2 μm cellulose filter. Physicochemical parameters, including EC, TDS, and chloride (Cl⁻) increased towards the coast, indicating progressive salinization. Ionic ratios: Na⁺/Cl⁻, Cl⁻/HCO₃⁻, SO₄²⁻/Cl⁻, Mg²⁺/Ca²⁺, Piper plots, and correlation matrices were employed to decipher the origin and extent of saline water mixing. Na–Cl facies, low Na⁺/Cl⁻ (