Geochemistry and Water Quality Assessment of Continental Intercalary Aquifer in Ouargla Region (Sahara, Algeria)

Abstract

Groundwater is vital for all living beings and the socio-economic development of arid regions. The present study evaluated the pertinence of groundwater of the continental intercalary (CI) aquifer in the Ouargla region for domestic and agricultural purposes. Sixteen (16) water samples were collected and analyzed for physical parameters, major cations and anions. The appreciation of groundwater potability was compared with the WHO (2017) standards. Agricultural water quality was evaluated using the Irrigation Water Quality Index (IWQI) method and the study of irrigation parameters: EC, SAR, SSP, PI, KR, PS and MAR. The results show that the CI waters are dominated by mixed Ca-Mg-Cl type (56.3%) and Ca-Cl type (43.7%). Natural rock-water interactions, including silicate weathering, evaporite dissolution and cation exchange, were the dominant processes controlling the mineralization of CI waters. According to WHO (2017), EC (100%), T (100%), TDS (100%), Na + (87.5%), K + (100%), Ca 2+ (12.5%), Mg 2+ (18.75%), SO 4 2-(100%), and TH (100%), samples exceed the permissible limit, indicating that most of the groundwater samples do not have good quality for drinking purposes. The calculated IWQI showed that 31.25% of the water samples were in the good category and 68.75% in the doubtful category.

Application of Water Quality Index to Assess the Potability of the Phreatic Aquifer in Ouargla (Algeria)

“…In the study area, the interpretation of logs of water and oil drilling shows that the basement contains three aquifers (Boussaada et al, 2023;Kharroubi et al, 2022;ANRH, 2004;OSS, 2003;UNESCO, 1972) these are from top to bottom, phreatic aquifer, the aquifer of the terminal complex (CT), and the aquifer of the intercalary continental (CI). The phreatic aquifer is unconfined, Quaternary and Mio-Pliocene age, represented by sands, sandstones, and gravels with gypsum and tuff levels (calcareous concretion) in chotts and sebkhas (Satouh et al,.…”

“…Because there is no natural outlet, the piezometric level at the surface has risen throughout the years of deep aquifer mining. The rising phenomena has had major environmental implications, such as oases degrading and groundwater quality changing (Boussaada et al, 2023;Satouh et al, 2021;Bouselsal et al, 2015). This phenomena has harmed most lower Saharan regions' water tables (Kharroubi et al, 2022) (the Ouargla basin, the valley of Oued Souf, and the valley of Oued Righ), resulting in major economic losses for the rehabilitation of degraded areas.…”

Evaluating Water Quality, Mineralization Mechanisms, and Potential Health Risks of Nitrate Contamination in the Continental Intercalaire Aquifer of Reggane, Algeria

“…The estimation of long-term, chronic health risks related to nitrate in groundwater for varying age groups followed the computational methodology proposed by the USEPA (Adimalla 2020; Zhang et al 2019;Egbueri et al 2023a, b), a method that quanti es potential risks associated with groundwater contaminants and provides scienti c guidance for water supply and treatment strategies. In evaluating the appropriateness of groundwater for irrigation, the Irrigation Water Quality Index method was implemented (Meireles et al 2010), complemented by analysis of factors impacting soil, plant, and water quality, such as the Kelly's ratio (KR), percentage of sodium (Na%), magnesium hazard (MH), and permeability index (PI) (Alum et Boussaada et al 2023). The analyses of mineralization processes and the contaminant sources in the Reganne groundwater are lacking in literature.…”