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- Groundwater vulnerability to nitrate contamination in an arid areaPublication . Abdelkarim, Bilel; antunes, Isabel Margarida; Agoubi, BelgacemABSTRACT: One of the major challenges in assessing groundwater vulnerability is the factors number and weight assigned. Therefore, to improve groundwater vulnerability assessment, a model independent of weight assignment errors must be considered. Groundwater specific vulnerability index (SVI) was applied in the region of Gabès (Tunisia). Intrinsic vulnerability index (IVI) assessment was firstly determined by the arithmetic mean calculation of index overlay method (IOM), based on the Depth of aquifer (D), annual average Precipitation (P), Lithology of the vadose zone (L) and percent of Slope (DPLS). Then SVI was assessed by linking new factors (Land Use and NO3-) to IVI. A total of one hundred groundwater samples were analysed for NO3-, exceeding 50 mg L-1. The spatial distribution of IVI shows four vulnerability classes: low (15%), moderate (35%), high (23%) and very high (27%). About 95% of the area registered high SVI values. This situation reinforces water-saving irrigation actions for adequate groundwater management.
- Assessment of groundwater vulnerability of fractured aquifers from arid regionsPublication . Abdelkarim, Bilel; antunes, Isabel Margarida; ABAAB, Nabil; Tounekti, Abdelbasset; Agoubi, BelgacemABSTRACT: Groundwater is the main water source of semi-arid regions. In these areas, it’s crucial to establish appropriate strategies for evaluating the vulnerability of aquifer systems and their potential exposure to contamination, especially in fractured aquifers, which possess a naturally high vulnerability. The aquifer system from Gabès region, southeastern Tunisia, is a fractured medium exposed to intensive agricultural activities with excessive fertilizer use. This study introduces a novel vulnerability index by incorporating the contribution of medium into the DRASTIC vulnerability method. The obtained results reveal the presence of zones with different degrees of vulnerability: very low (9.6%), low (15%), moderate (22.9%), high (21.5%), and very high vulnerability (31%). The spatial distribution of this new vulnerability index proves to be a valuable tool for effective groundwater management and the identification of suitable locations for new wells and boreholes in the region of Gabès.
- Copiapite group: occurrence and properties in mining contamination scenariosPublication . Barroso, Ana; Valente, Teresa; antunes, Isabel Margarida; Reis, Amelia; Correia Neves, IsabelABSTRACT: The copiapite group shows a wide range of chemical compositions, allowing the identification of several mineral phases (e.g., aluminocopiapite and magnesiocopiapite). These minerals, typically observed in mining environments, are formed from evaporation and acid mine drainage (AMD) precipitation. In these areas, the copiapite has been studied to comprehend its ability to store some potentially toxic elements (PTE), specifically the As. Therefore, the present work aims to characterize mineral samples of copiapite using different techniques (binocular microscope, XRD, SEM-EDS, and FTIR) to understand their morphology, mineralogical and chemical composition, and environmental role. Copiapite samples were collected in two abandoned mining areas of the Iberian Pyrite Belt (IPB): São Domingos (Portugal) and Trimpancho (Spain). The results from the mining areas showed differences corresponding to two phases of the copiapite group, expressed by distinct occurrence modes and variations in morphology and chemical composition.