Spatial variation of groundwater vulnerability to nitrate pollution under excessive fertilization using index overlay method in central Tunisia (Sidi Bouzid basin)*

Abstract

One of the major challenges in assessing groundwater vulnerability to pollution is the inadequate factors number and weight. Therefore, to carefully improve the assessment of groundwater vulnerability, a model independent of weight assignment errors was used. Moreover, the specific vulnerability index (SVI) of Sidi Bouzid North's groundwater was assessed in this study. Intrinsic vulnerability index (IVI) assessment was determined in the first step by the arithmetic mean calculation by the index overlay method (IOM) based on the D: Depth of aquifer; P: annual average Precipitation; L: Lithology of the vadose zone and S: percent of Slope (DPLS) model. Then SVI was assessed by linking new factors (LU and NO 3 − ) to IVI. Consequently, 83 samples were analysed for NO 3 − , showing high values that exceed 50 mg l¹. The spatial distribution of IVI shows three vulnerability classes in the study area, namely low (8%), moderate (15%)and high (77%). The evaluation of SVI based on the risks associated with the NO 3 − and LU factors using GIS indicates that about 95% of the total study area is classified with high SVI levels. It displayed a good correlation with NO 3 − and provided a high discretization of the groundwater risk from natural and anthropogenic pollution. This alarming situation suggests the necessity to apply water-saving irrigation action for adequate water management.

Groundwater chemistry, pollution and health risk assessment for nitrogen compounds. A case study in a suburban region of Romania

“…The final groundwater quality map was created by overlapping all weighted value to delimit the groundwater quality in the study area [32].…”

Use of Hydro-chemical Tools to Improve Definitions of the North-Western Sahara Aquifer System, Case of Ouargla Groundwater, Algeria

“…The problem of groundwater chemistry has been addressed by innumerable research worldwide (Belkesier et al, 2018;Benmarce et al, 2021;Bouselsal and Saibi, 2022;Brahmi et al, 2021;Hamad et al, 2022Hamad et al, , 2022Ncibi et al, 2021;Nekkoub et al, 2020).…”

Study of Hydrogeological Functioning of Complex Terminal (Ct) Aquifer, Using Hydrogeochemical and Isotopic Tools: Case Study of Oued Souf Region (Southeast of Algeria)

“…This poor-quality water can alter soil physicochemical properties causing soil degradation, reducing the productivity as consequence [7], [8], [9]. For permanent water exploitation, deep aquifers hosted in a large sedimentary series which embodies a huge stock of groundwater regard to climate variability and pollution risks [10], [11], [12]. The Continental Intercalaire (CI) aquifer of North Africa is the CI aquifer in Algeria, Tunisia and Libya, is considered as an area with a large artesian basin, from the west (Grand Erg Septentrional) to the east (to the Fezzan of Libya) as well as to the southern Sahara basins [13].…”