Assessment of groundwater quality based on GIS and geochemical methods: coastal aquifer of Bouficha (North-Eastern Tunisia)

• Published in: Journal of coastal conservation 2020-08, Vol.24 (4), p.1-20, Article 45
• Main Authors: Hamzaoui-Azaza, Fadoua, Ameur, Meriem, Chaouch, Refka, Cheikha, Lilia Ben, Gueddari, Moncef, Carrillo-Rivera, José J.
• Format: Article
• Language: English
• Subjects: Anions; Anthropogenic factors; Aquifers; Carbonates; Cations; Coastal aquifers; Coastal Sciences; Contamination; Deterioration; Drinking water; Earth and Environmental Science; Economic activities; Electrical conductivity; Electrical resistivity; Exploitation; Fertilizers; Fluorides; Geochemistry; Geographic information systems; Geographical information systems; Geography; Groundwater; Groundwater data; Groundwater irrigation; Groundwater pollution; Hazard assessment; Health risks; Human influences; Industrial applications; Information systems; Interpolation; Irrigation; Land cover; Land pollution; Land use; Landsat; Landsat satellites; Magnesium; Nature Conservation; Oceanography; Pollutants; Pollution sources; Quality; Quality assessment; Remote sensing; Remote Sensing/Photogrammetry; Satellite imagery; Sodium; Sodium carbonate; Spatial analysis; Statistical analysis; Statistical methods; Sulphates; Water analysis; Water pollution; Water quality; Water quality assessments; Water sampling
• ISSN: 1400-0350; 1874-7841
• DOI: 10.1007/s11852-020-00762-8

In Tunisia, Groundwater is an important water source for domestic, agricultural and industrial uses, but the deterioration of its quality, under the influence of anthropogenic activities and natural factors, limits its suitability for human consumption and irrigation. The present study was carried out to assess groundwater quality in Bouficha aquifer in north-eastern Tunisia using geochemical, geospatial and statistical techniques. The relationship between groundwater quality and Land Use Land Cover (LULC) patterns were also explored using remote sensing, geographic information system (GIS) and Landsat satellite images. Groundwater samples were collected from sixteen wells in April 2015 and analyzed for their physical and chemical characteristics. Concentrations of major cations and anions in the groundwater vary spatially. The dominant water types in the investigation area are Na-Cl and Ca–SO₄. Abasic statistical study, applying hierarchical classification analysis confirms the existence of two groundwater types. To evaluate the suitability of groundwater for irrigation, chemical data were assessed using methods such as Electrical Conductivity, Kelley’s ratio, Sodium Absorption Ratio, Magnesium Hazards, as well as Residual Sodium Carbonate. Regarding drinking groundwater assessment, the World Health Organization (WHO) standards were applied to define sites with drinking water permissible levels. Information was loaded in an ArcGIS software and analyzed with a Spatial Analyst extension using Inverse Spline interpolation methods. Fluoride content in most samples has values as high as 1.97 mg/L, with 53% of the samples showing fluoride concentration higher than the level suggested by the WHO for drinking water of 1.5 mg/L and ratified by the National Society of Exploitation and Drinking Potable Water of Tunisia. Additionally, reported nitrate concentrations are higher than the expected groundwater background level of 10 mg/L; indeed, values are up to 286 mg/L, being hazardous for domestic use and suggesting the presence of anthropogenic sources of water contamination. The Land Use and Land Cover (LULCC) of Bouficha aquifer were changed over seventeen years. The Landsat satellite images have shown that the built-up area increased from 2001 to 2018 to the detriment of water and crop vegetation. The overuse of fertilizers on a total agricultural area of Bouficha aquifer (60%) led to significant pollutants, including nitrate and a deterioration in its water qual