Determination of Physico-chemical Parameters of Well Water in the Central Niayes Area of Mboro (Senegal)

The Niayes of Mboro zone has significant hydro-agricultural potential and is marked by a diversity of crops. It is Senegal's main market-garden production zone. The Mboro area is characterized by a landscape of depressions and dunes resting on a shallow water table. There are generally no permanent watercourses, and the region's only significant water resource is the water table located in the quaternary coastal aquifers, which is influenced by several anthropogenic factors. The aim of this study was to determine the physico-chemical quality of water from four wells in the Mboro region, located in the hydromorphic zone of the Niayes. pH, temperature, total dissolved solids (TDS) and electrical conductivity (EC) were measured using a portable multiparameter, and chemical parameters by UV-visible spectrophotometry. The results show that the physical parameters comply with WHO standards (2000 for EC, 1000 for TDS and between 6.5 and 8.5 for pH), with the exception of the temperature of wells P2, P3 and P4, which varied between 25.9 and 28.4°C. The chemical study shows the presence of phosphate, sulfate, nitrate, fluoride and chloride ions at levels ranging from 0.1 mg/L (F<sup>-</sup>) to 400 mg/L (Cl<sup>-</sup>). The chloride content (400 mg/L) and CaCO<sub>3</sub> hardness (284.8 mg/L) in well P2 exceed WHO standards of 250 and 200 mg/L respectively. Phosphate (PO<sub>4</sub>-P) ion levels in all four wells are equal to 0.8 mg/L. This value is higher than the recommended guide. This value is higher than the recommended guide value of 0.5 mg/L. Spatio-temporal variations in physico-chemical parameters appear to depend on the direction of water flow, the geological nature of the terrain crossed, the geographical position of the wells, the depth of the water tables tapped, industrial activities, the intrusion of marine water and the use of fertilizers. On the whole, the water from the wells studied is of good quality and suitable for irrigation and human consumption.