The Issue of Groundwater Salinization in Coastal Areas of the Mediterranean Region: A Review

Abstract

The Mediterranean area is undergoing intensive demographic, social, cultural, economic, and environmental changes. This generates multiple environmental pressures such as increased demand for water resources, generation of pollution related to wastewater discharge, and land consumption. In the Mediterranean area, recent climate change studies forecast large impacts on the hydrologic cycle. Thus, in the next years, surface and ground-water resources will be gradually more stressed, especially in coastal areas. In this review paper, the historical and geographical distribution of peer-review studies and the main mechanisms that promote aquifer salinization in the Mediterranean area are critically discussed, providing the state of the art on topics such as actual saltwater wedge characterization, paleo-salinities in coastal areas, water-rock interactions, geophysical techniques aimed at delineating the areal and vertical extent of saltwater intrusion, management of groundwater overexploitation using numerical models and GIS mapping techniques for aquifer vulnerability to salinization. Each of the above-mentioned approaches has potential advantages and drawbacks; thus, the best tactic to tackle coastal aquifer management is to employ a combination of approaches. Finally, the number of studies focusing on predictions of climate change effects on coastal aquifers are growing but are still very limited and surely need further research.

Assessment of Groundwater Quality and Pollution in the Songnen Plain of Jilin Province, Northeast China

“…At the same time, the possibility of pollution cannot be excluded. The high Fe content in this area is mainly caused by the primary sedimentary environment [50,51]. The underground rocks in this area contain a large number of iron compounds that enter the groundwater during the deposition process.…”

Special Issue “Focus on the Salinization Issue in the Mediterranean Area”

“…The main goal of this Special Issue of Water is to focus on different methodological approaches to improve the understanding of salinization mechanisms of both groundwater and soil water, which may derive from actual seawater intrusion, paleo-seawater intrusion, an increase in atmospheric temperatures that in turn drives evapoconcentration and agricultural return flows. From its first announcement, and after being thoroughly peer reviewed, six papers have been accepted for publication [10][11][12][13][14][15]. To gain an overview of the ideas collected by this Special Issue, a brief summary of each published paper is reported below.…”

“…In a different line of research, the study presented by Kasim et al [14] analyzed the salt-affected land which is predominant in the Keriya River area of Northwestern China via satellite band reflectance and newly optimum spectral indices (OSIs) based on two-dimensional and three-dimensional data. Finally, a review paper closes this Special Issue discussing the new advances and challenges that still must be faced in the Mediterranean with a special focus on predictions of climate change effects on coastal aquifers, which surely deserve additional research [15].…”

Hydrochemical, Isotopic, and Geophysical Studies Applied to the Evaluation of Groundwater Salinization Processes in Quaternary Beach Ridges in a Semiarid Coastal Area of Northern Patagonia, Argentina

“…This determines that, in many coastal areas of the world, the only freshwater available sources are in the shape of lenses related to beach ridges and dune deposits [11][12][13][14][15][16]. These freshwater resources are usually relatively small, but significant for the development of coastal populations [17][18][19][20][21].…”