Hydrochemical and isotopic characterization of groundwater in the southeastern part of the Plateaux Region,Togo |
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| Authors: | Kossitse Venyo Akpataku Shive Prakash Rai Masamaéya Dadja-Toyou Gnazou Lallébila Tampo Limam Moctar Bawa Gbandi Djaneye-Boundjou |
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| Institution: | 1. Laboratory of Water Chemistry, Faculty of Sciences, University of Lomé, Lomé Togo;2. Department of Geology, Cheikh Anta DIOP University, Dakar, Senegal;3. Hydrological Investigations Division, National Institute of Hydrology, Roorkee, India;4. Department of Geology, Faculty of Science, University of Lomé, Lomé, Togo |
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| Abstract: | Hydrochemical, inverse geochemical modelling and isotopic approaches are used to assess the hydrogeochemical evolution of groundwater from the basement aquifers in the southeastern part of the Plateaux Region, Togo. Groundwater originates from present-day rainwater infiltration and is mostly fresh and slightly acidic to neutral. Hydrochemical facies are predominantly mixed cations-HCO3 associated with Ca/Mg-Cl, Na-HCO3 and Na-Cl water types in equilibrium with kaolinite and Ca/Mg-smectites. They are related to silicates hydrolysis, anthropogenic contamination, nitrification/denitrification, mixing along flowpaths and dissolution/precipitation of secondary minerals. The pattern of flow paths is in accordance with an increasing trend in total dissolved solids (TDS) toward the potentiometric depression located in the central and southern parts of the aquifer system. Inverse geochemical modelling using the NETPATH-WIN model showed the relative importance of biotite, plagioclase and amphibole weathering and dissolution of secondary carbonate minerals along the flowpath, suggesting that an abundance of minerals is not necessarily the main factor controlling the groundwater chemistry evolution. |
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| Keywords: | hydrochemistry isotopes basement aquifers Plateaux Region Togo |
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