Hydrogeochemical Appraisal of Groundwater Quality and Its Suitability for Drinking and Irrigation Purposes in the West Central Senegal

Abstract

Groundwater has been the main resource used for drinking, domestic and agricultural activities in West central Senegal for the past few decades. Thus, this study investigates the quality of groundwater and assesses its suitability for drinking and irrigation purposes. To this end, 42 samples were collected and analyzed for various chemical parameters (major ions, fluoride, pH, total dissolved solids (TDS)). Chemical data were interpreted using water quality indexes, Wilcox and USSL salinity diagrams, bivariate plots, ionic ratios and by comparing with the WHO standards. Results indicated that the groundwater is neutral to slightly alkaline with pH values between 7.1 and 8.2. Piper diagram shows that mixte-Ca-Na-Mg-HCO3 is the dominant hydrochemical facies. TDS and water quality index (WQI) values indicated respectively that 69% and 64.3% of samples were suitable for drinking. Moreover, major ions concentrations were found below the desirable limits in most of groundwater samples. However, for fluoride, 69% of samples exceed the WHO guideline, limiting their use for drinking. The computed index of irrigation water quality and Wilcox diagram reveal that 87% and 78% of samples belong, respectively, to excellent to good category and excellent to good and good to permissible. Similarly, according to the US salinity classification, the majority of samples were acceptable for irrigation. Gibbs plots illustrate that water-rocks interaction with some extent evaporation is the main hydrochemical process controlling groundwater chemistry while bivariate plots and ionic ratios indicate that mineral dissolution and ion exchange play important role in groundwater chemistry.

Investigating Seawater Intrusion in Republic of South Africa’s Heuningnes, Cape Agulhas Using Hydrogeochemistry and Seawater Fraction Techniques

“…The high content of TDS in water can be due to anthropogenic sources such as domestic sewage, septic tanks, and agricultural activities. Higher concentrations of TDS cause gastrointestinal irritation in humans and may also lead to laxative effects [5]. The maximum permissible limit of TDS in drinking water is 1000 mg/L [28].…”

“…The behavior of saline groundwater flow has been described in previous research using a mixture of chemical and isotopic markers, defining flow patterns, and identifying groundwater salinization processes [5][6][7]. Their application includes studying how the freshwater-saltwater interface moves and comprehending how various coastal aquifers' saline water bodies and surrounding freshwater interact with one another.…”