RESUMEN
The aquifer system of Menzel Bourguiba, located in northeastern Tunisia, is an important groundwater resource that, for the last decades, has been a subject of excessive use by agricultural and industrial activities leading to the degradation of its water quality. To better understand the hydrochemistry of these aquifers, identify the main factors controlling their mineralization, and assess their suitability for drinking and agricultural purposes, 35 groundwater samples collected during the campaign of October 2019 were analyzed by different physicochemical methods. The results showed that the hydrochemical facies of the study area is characterized by two major types SO4-Cl-Ca and Na-Cl. The total dissolved solids (TDS) values range from 0.5 to 1.9 g/L in the shallow aquifer and from 0.6 to 2 g/L in the deep aquifer. The high rates are recognized downstream of the studied basin. The interpretation of multivariate statistical analysis and geochemical approaches revealed that rock-water interaction, dissolution and precipitation process, ionic exchange mechanisms, water irrigation return, and marine intrusion are the main factors controlling the mineralization of the study area groundwater. The comparison of the analytical data to the Tunisian and World Health Organization (WHO) standards unveiled that the majority of groundwater samples are unsuitable for drinking because of high nitrate contents, elevated electrical conductivity (EC), TDS values, and high concentrations of some chemical parameters. In addition, the sodium absorption ratio and the sodium percent parameters indicated that most of the analyzed samples are inappropriate for irrigation uses.
Asunto(s)
Agua Subterránea , Contaminantes Químicos del Agua , Monitoreo del Ambiente/métodos , Agua Subterránea/química , Sodio/análisis , Túnez , Contaminantes Químicos del Agua/análisis , Calidad del AguaRESUMEN
Temperature, pH and trace elements (F, P, Cr, Cu, Zn, Cd, and Pb) contents were determined in 16 stations as well as in 2 industrial and 2 domestic discharge sources, in the central coastal area of the Gulf of Gabes. Compared to the northern and southern areas of the study area, the highest contents of contaminants were reached in the central area which hosts the coastal industrial complex. The seawater in this central area was also found to be acid and of higher temperature. Based on the Water Pollution Index results, an increasing degradation gradient of the seawater quality was revealed from northern and/or southern stations to central ones, categorized as 'strongly to seriously affected'. Phosphogypsum wastes dumped by the Tunisian Chemical Group (GCT) seem to have continuously degraded the seawater quality in the study area. A rapid intervention is needed to stop the effects on the marine environment.