Contribution to the Hydrochemical Study of Groundwater from the Continental Terminal in Saloum

Abstract

This paper focuses on the study of the aquifer of the Continental Terminal in the south of Saloum river. This study aims to participate in the knowledge of the physicochemical quality and to help understand the origins and processes of the mineralization of the water of the Continental Terminal (CT). Physicochemical treatments show an average pH of 6.61 indicating a slightly acidic water overall. The electrical conductivity varies between 37.4 and 12,320 µS·cm −1 with an average of 729.3 µS·cm −1 . High conductivities are recorded around the ocean and the Saloum River, indicating higher mineralized waters in these areas. The geochemical study and multivariate statistical analysis indicate three groups of the sampled waters. Group 1 is mainly formed of the Ca-HCO 3 , Na-HCO 3 , Ca-Cl and Na-Cl facies. This group is the most common one and is found throughout the southern Saloum area. Group 2, mainly made up of the Ca-HCO 3 and Na-HCO 3 facies, is located in the center, east, west and north of the zone. The mineralization of these two groups is believed to be of carbonate, evaporitic and/or anthropogenic origin. Group 3 is formed from the Na-Cl facies. This group is located in the north and west of the area (near the ocean and the Saloum river). This group 3 suggests pollution of marine and anthropogenic origin. The calculated base indices suggest cationic exchanges between the waters and the formations of the water table of the terminal continental.