Assessment of the suitability of groundwater quality for drinking and irrigation purposes using water quality indices: a case study of the Ghardimaou shallow aquifer, North-western Tunisia

• Published in: Arabian journal of geosciences 2021-12, Vol.14 (23), Article 2584
• Main Authors: Moussa, Amor Ben, Guerchi, Amal, Salem, Sarra Bel Haj
• Format: Article
• Language: English
• Subjects: Agricultural land; Agricultural production; Anhydrite; Aquifers; Cation exchange; Cation exchanging; Cations; Chemical composition; Crop yield; Drinking water; Earth and Environmental Science; Earth science; Earth Sciences; Economic development; Economics; Evaluation; Evaporites; Global Changes and Groundwater Responses; Groundwater; Groundwater irrigation; Groundwater management; Groundwater quality; Gypsum; Halite; Hydrodynamics; Ion concentration; Irrigation; Irrigation water; Land use; Mineralization; Original Paper; Quality assessment; Socioeconomic aspects; Sodium; Soil; Soil contamination; Soil structure; Sulphates; Sustainable development; Tracers; Water demand; Water monitoring; Water pollution; Water Quality; Water resources
• ISSN: 1866-7511; 1866-7538
• DOI: 10.1007/s12517-021-08712-w

During the last few decades, climate and land use change has induced an over-pumping of groundwater resources to meet the growing demand for water to provide irrigation and potable supplies. The impact of such practices on the aquifer hydrodynamics and groundwater quality should be evaluated by using a set of tracers. Furthermore, in the Ghardimaou plain, North-eastern Tunisia, groundwater is the major water resource for sustainable socio-economic development. Therefore, continuous groundwater monitoring is essential to maintain its quality and increase agricultural productivity. The present study, which reports the first hydrochemichal investigation of the Ghardimaou shallow aquifer groundwater, aims to explore its chemical composition and to evaluate its suitability for drinking and irrigation purpose. Physico-chemical parameters and major ion concentration were used to distinguish the main mineralization processes and to assess the groundwater quality. Groundwater suitability for irrigation was evaluated basing on water quality indices (WQI) such as percentage of sodium (%Na), ratio of sodium adsorption (SAR), and Kelly ratio (KR). It has been demonstrated that the Ghardimaou groundwater is mainly of Cl-SO 4 -Ca type, highlighting the impact water–rock interaction processes related to the dissolution of evaporite minerals (halite, gypsum, and anhydrite) and cation exchange. These mineralization processes have resulted in high ion concentrations exceeding, generally, the World Health Organization (WHO) threshold value for drinking water. The calculated WQI suggest that a major part of the Ghardimaou shallow groundwater is unsuitability for irrigation. However, the irrigation with this contaminated water in long term may affect soil structure, i.e., reduce the hydraulic conductivity of irrigated soil and reduction in crop yield. Consequently, groundwater management will allow farmers to be meaningfully involved in decisions defining the future of their agricultural land and the quality of water resources.