Hydrogeochemical and salinity appraisal of surficial lens of freshwater aquifer along Lagos coastal belt, South West, Nigeria

摘要: In order to determine the hydrogeochemical processes and salinity status of the surficial lens of freshwater aquifer in the Lagos coastal basin, physicochemical parameters and hydrogeochemical tools were employed in this study. These tools include existing methods such as Piper diagram, Durov diagram, Gibb's diagram, statistical analysis and geochemical modelling, and the newly proposed cationic contribution evaluation and ionic ratio bivariate plots. The Piper plot revealed that chemical facies is rich in (Ca, Mg, Cl and HCO3) and (Ca and HCO3) for the groundwater in both wet and dry seasons while Mg–Cl and Na–Cl water types characterised the lagoon and the Ocean, respectively. The surficial aquifer is an essentially freshwater in the dry season and partly saline in the wet season due to flash flood, marine aerosol precipitation and infiltration from the surrounding brackish surface waters. The Ca2++Mg2 …