Spatial and Temporal Variations of Water Quality of Mateur Aquifer (Northeastern Tunisia): Suitability for Irrigation and Drinking Purposes

Abstract

The present study aims to assess the spatial and temporal variations of the hydrochemical characteristics of Mateur aquifer groundwaters, a crucial water resource in the northeast of Tunisia. The aquifer was subject to water quality deterioration due to salinization and nitrate contamination, and a new assessment of water quality was needed. For this purpose, 40 groundwater samples were collected during wet and dry seasons and analyzed for salinity, pH, T, O2, major cations and anions, and nutrient elements using standard methods and Water Quality Index (WQI). The results showed that most of the groundwater parameters were not within the permissible limits set by the World Health Organization in both seasons. The geochemical data were interpreted using WQI for drinking water. The spatial distribution maps of Water Quality Index showed that the highest quality was found, during both seasons, in the northwest and the southeast part of the aquifer, corresponding to the recharge zone, whereas the poor and very poor water quality was found in the outflow part of the aquifer. According to sodium adsorption ratio (SAR) and Na% values, most of the groundwater samples were not suitable for irrigation purposes and characterizing the eastern part of the aquifer and the outflow part of the aquifer, around the Ichkeul marshes.