Chemical and isotopic evaluation of groundwater salinization processes in the Djebeniana coastal aquifer, Tunisia

Moussaoui, Ilhem; Rosa, Éric; Cloutier, Vincent; Neculita, Carmen Mihaela; Dassi, Lassâad

doi:10.1016/j.apgeochem.2022.105555

Cited by 10 publications

(5 citation statements)

References 38 publications

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“…Figure 6 demonstrates the proximity of brine samples to the evaporation line, while Figure 8 showcases negative δ 37 Cl values in the brine, signifying a substantial evaporation process during its formation. Typically, as the proportion of fresh groundwater increases, both Cl − concentration and δ 37 Cl decrease [94]. The negative δ 37 Cl values observed in brine, when compared to seawater, provide clear evidence of brine's interaction with ancient atmospheric precipitation during its genesis [93].…”

Section: Genesis Of Brine: Seawater Evaporation Halogen Precipitation...mentioning

confidence: 96%

Unraveling the Complexities of Groundwater Salinization in Coastal Environments: Insights from Laizhou Bay’s Eastern Coast, China

Huang,

Ma,

Zhou

2023

Water

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Coastal areas have made substantial contributions to global economic development but are plagued by challenges such as groundwater salinization. Groundwater serves as the primary source for drinking, industrial, and domestic purposes in these coastal areas. Therefore, understanding the causes and processes of groundwater salinization holds paramount significance for effective groundwater management. The coastal area of Laizhou Bay in northern China serves as a quintessential example of such a scenario. With substantial groundwater extraction and severe groundwater salinization issues, it exacerbates the disparity between water-resource supply and demand. Currently, our understanding of the processes and influencing factors related to groundwater salinization in this region remains limited. In this study, employing hydrochemical and stable chlorine isotope analyses on 35 groundwater and seawater samples, an in-depth investigation into the complex mechanisms underlying groundwater salinization in the Quaternary aquifers of the eastern coastal plain of Laizhou Bay was conducted. The test results of the samples indicate that brine and saline groundwater are primarily of the Na-Cl type, exhibiting a hydrochemical composition similar to that of seawater. Brackish groundwater exhibits a diverse hydrochemical composition. The hydrogen and oxygen isotope characteristics of brackish and fresh groundwater resemble atmospheric precipitation, while brine, seawater, and saline groundwater show hydrogen and oxygen isotope depletion. Compared to seawater, brine exhibits significant δ37Cl depletion. The analysis of the test results reveals that the formation of brine aquifers results from a complex interplay of climate change, tectonic movements, and sea–land evolution, involving lagoon development during seawater regression, salt concentration through evaporation, and subsequent water–rock interactions. The genesis of saline groundwater involves a complex interplay of brine–seawater mixing, significant evaporation, and potential input of fresh groundwater from atmospheric precipitation and river sources. The formation of brackish groundwater is predominantly influenced by atmospheric precipitation, and agricultural activities, with significant variations in NO3− concentrations attributed to varying intensities of fertilizer application in the northern plain area. These insights contribute to a deeper understanding of the origins of groundwater and can inform the development of policies for groundwater protection in this area.

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Section: Genesis Of Brine: Seawater Evaporation Halogen Precipitation...mentioning

confidence: 96%

Unraveling the Complexities of Groundwater Salinization in Coastal Environments: Insights from Laizhou Bay’s Eastern Coast, China

Huang,

Ma,

Zhou

2023

Water

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“…Unplanned management of these groundwater resources can lead to deterioration of lens water quality. Among the main management problems are the intensive exploitation that causes the salinization of the lenses due to marine intrusion (Alfarrah et al, 2017; Askri et al, 2016; Moussaoui et al, 2023; Ruffine et al, 2021), and the presence of contamination sources such as septic tanks and garbage dumps (Lutterodt et al, 2021; Wu et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Hydrogeochemical processes as a conditioner of freshwater lenses associated with coastal deposits

Julieta,

Álvarez,

Carolina

et al. 2024

Hydrological Processes

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The aim of this work was to study the processes and factors conditioning the hydrochemistry of freshwater lenses associated with Holocene coastal deposits in an area of the Argentinean Atlantic coast. For this purpose, geomorphological units were mapped and a shallow groundwater monitoring network was established, including pre‐existing boreholes and shallow exploration wells. During the construction of the shallow exploration wells, sediment samples were extracted to determine the texture and mineralogical characteristics. Four samplings were carried out to measure in situ physicochemical parameters and to determine majority ions in the water. The chemical data were analysed considering the associated geomorphology, lithology, water balance and hydrodynamics. The geomorphological and lithological characteristics are the combined factors that favour the preferential rainwater recharge processes. Geoforms with greater topography and extension (continental and coastal dunes) tend to store freshwater lenses, while those with lower topography and little areal extension (sand sheets and beach ridges) have very thin lenses and tend to become salinized. Climate and local water balance are factor that determines that groundwater recharge occurs preferentially in winter. This causes increases in groundwater levels and a decrease in the groundwater EC. On the other hand, mineralogy is a factor that conditions the geochemical processes associated with the water–sediment interaction. Within the main geochemical processes, the dissolution and/or mineral weathering, the dissolution of CO2(g) and ion exchange determine the presence of different hydrochemical facies, where Ca‐HCO3 facies dominates in elevated geoforms, while Na‐Cl in lower ones. The results obtained in this work have provided an understanding of the factors and processes that condition groundwater chemistry in coastal deposits, being of vital importance for the management of water resources.

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“…Additionally, high salinity levels in groundwater, particularly in arid and semi-arid regions, can increase soil salinity through capillary action, affecting agricultural productivity. Global groundwater salinization has gained significant attention from the international community (Yakirevich et al, 1998;Moussaoui et al, 2023;Parisi et al, 2023). The main mechanisms contributing to groundwater salinization are: (1) Modern seawater intrusion due to rising sea levels caused by global warming (Laattoe et al, 2013;Agossou et al, 2022;Balasubramanian et al, 2022;Sathish et al, 2022); (2) Modern seawater intrusion resulting from excessive groundwater extraction and hydraulic reclamation (Chen et al, 2021;Lio et al, 2015); and…”

Section: Introductionmentioning

confidence: 99%

Groundwater salinization under the influence of paleo sea-level fluctuation: a case study in southern Laizhou Bay, China

Cui,

Chen,

Chen

et al. 2024

Front. Mar. Sci.

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The groundwater environment in low-lying coastal regions is significantly impacted by global sea-level fluctuation. In Laizhou Bay, three large-scale transgressions have occurred since the late Pleistocene, resulting in the transformation of ancient seawater into brine. This brine has become a major contributor to groundwater salinity in the area. This study establishes a correlation between groundwater occurrence and paleoclimate changes in Laizhou Bay using borehole sediment data. The source and mechanism of groundwater salinity are analyzed based on sediment pore water characteristics and hydrogen and oxygen isotopes. The study reveals that the stratigraphic structures in the area consist of four layers: a Holocene transgressive layer, a continental confining bed from the late Pleistocene, a Cangzhou transgressive layer from the late Pleistocene, and a fluvial aquifer from the middle Pleistocene. All aquifers in the study area have been infiltrated by modern seawater, with the uppermost Holocene aquifer influenced by evaporation and leaching processes, the central late Pleistocene aquifer remaining relatively stable, and the lower middle Pleistocene aquifer affected by subsurface low salinity runoff and exhibiting an increasing trend with depth. Given the presence of numerous hydrogeological environments globally that are similar to the study area, the obtained mechanisms of groundwater salinization in this study will provide theoretical support for groundwater management in similar regions worldwide.

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Chemical and isotopic evaluation of groundwater salinization processes in the Djebeniana coastal aquifer, Tunisia

Cited by 10 publications

References 38 publications

Unraveling the Complexities of Groundwater Salinization in Coastal Environments: Insights from Laizhou Bay’s Eastern Coast, China

Unraveling the Complexities of Groundwater Salinization in Coastal Environments: Insights from Laizhou Bay’s Eastern Coast, China

Hydrogeochemical processes as a conditioner of freshwater lenses associated with coastal deposits

Groundwater salinization under the influence of paleo sea-level fluctuation: a case study in southern Laizhou Bay, China

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