Inferred Industrial and Agricultural Activities Impact on Groundwater Quality of Skhira Coastal Phreatic Aquifer in Southeast of Tunisia (Mediterranean Region)

Abstract

In Tunisia, it has been proven through various previously published studies that agricultural overexploitation and urban and industrial activities increase the risk of groundwater quality deterioration. The present study is a new research to be added to groundwater appraisal and comes to assess groundwater quality of the phreatic Skhira aquifer in relation to surrounding anthropic activities and also tries to evaluate potential risk threatenings of the local population. For that, 20 water well samples covering the phreatic aquifer were analyzed for physical and chemical parameters, major cations and anions, nutrient elements, fluorine, and some trace metal elements. Results show that the area close to the phosphogypsum storage site is the zone which is the most affected by industrial activity. This area corresponds to the upstream part of the aquifer, in terms of the trending flow, and records the highest conductivity values, high H2PO4-, F-, SO42-, and Zn2+ concentrations. Groundwater samples in this area are also characterized by a relatively low hydrogen potential (acid pH). High NO3- are recorded especially upstream of the aquifer and are thought to be caused by high fertilizer use. Overall, most analyzed samples do not meet the World Health Organization norms and therefore are not suitable as drinking waters. In addition, well water use for irrigation represents a medium to high sodicity and alkanization risk. The current study sheds light on the increasing deterioration risk of the aquifer and is an awakening call for decision-makers to imply means for urgent solutions.