Groundwater Chemistry of the Mornag Aquifer System in NE Tunisia |
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Authors: | Boutheina Farhat Abdallah Ben Mammou Lamia Kouzana Ismail Chenini Francesca Podda Giovanni De Giudici |
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Affiliation: | 1. Department of Geology, Faculty of Sciences of Tunis, Minerals Resources and Environment Laboratory, Tunis El Manar, Tunisia;2. Earth Science Department, University of Cagliari, Cagliari, Italy |
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Abstract: | The present paper investigates hydrochemical processes and water quality in the Mornag aquifer in NE Tunisia. Groundwater samples were collected during a field campaign, and were analysed for major and trace elements. The collected waters have a chemical facies rich in Ca2+, Na+ and Cl-. Piper diagram shows a progressive increase in chloride ions along with increasing salinity. Saturation indexes calculated by using PHREEQC (USGS) show that the Mornag waters are slightly saturated with respect to carbonates (calcite and dolomite), while undersaturated with respect to gypsum, halite and other evaporitic minerals. The current composition of waters takes place via dissolution of halite and Ca-sulfates, where the increase in calcium is partially balanced by possible calcite precipitation. The relevant recorded pollutant is nitrate, which was likely dispersed from agricultural soils, while heavy metals were generally far below values of pollution thresholds, indicating no influence by mining activity. |
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Keywords: | groundwaters Mornag plain water salinity water-rock interaction |
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