Assessment of the water quality of the Téboulba aquifer: contamination risk for agricultural soils
This study focuses on the groundwater quality of Téboulba, a very important region for Tunisian agriculture. Groundwater samples were taken from five wells used for irrigation in three farms. Well water had basic pH and a high salinity (3.61-7.26 dS∙m-1) dominated by Na+ and Cl- ions. The concentrations of Pb, Zn, Cu, and Mn were below the limits, those of Cr, Cd and Co were close to or exceeded the limits. To assess the long-term consequences of irrigation with polluted groundwater, the quality of the irrigated soils was tested with a micronucleus test by means of an exposure of Vicia faba roots to the soil leachates. The tests did not show significant differences in their mitotic index and in the number of micronuclei compared to control leachates from non-irrigated soils. However, chromosome and nuclear aberrations were found in all leachates . Despite the contamination of well waters, probably caused by industrial and agricultural activities, the soils did not show signs of genotoxicity. A more detailed study would be needed to find the origins of the contamination in order to prevent further deterioration of the groundwater quality.