Hydrochemical and isotopic characterization of groundwater in the southeastern part of the Plateaux Region,Togo     

Kossitse Venyo Akpataku  Shive Prakash Rai  Masamaéya Dadja-Toyou Gnazou  Lallébila Tampo  Limam Moctar Bawa  Gbandi Djaneye-Boundjou 《水文科学杂志》2019,64(8):983-1000

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.  相似文献