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Alexakis, D., Gotsis, D., & Giakoumakis, S. (2015). Evaluation of soil salinization in a Mediterranean site (Agoulinitsa district—West Greece). Arabian Journal of Geosciences, 8(3), 1373–1383.
Abstract: Soil salinization is an environmental problem having
significant impacts on the soil–water–plant system. This
problem is more frequent in coastal areas due to seawater
intrusion into the land. Assessing the soil salinization is a
critical issue for the agricultural areas situated in the
Mediterranean basin. This paper examines the deterioration
of soil quality in the cultivated land of a Mediterranean site
(Agoulinitsa district—West Greece). Soil samples were collected
in both pre-irrigation and post-irrigation seasons.
Electrical conductivity (EC), pH and the ions Br−, Ca2+, Cl−,
F−, K+, Li+, Mg2+, Na+, NH4
+, NO2
−, NO3
−, PO4
3− and SO4
2−
were determined by the 1:2 (soil/water ratio on weight basis)
method. The salts which were present in both seasons in the
soils of the area studied are KCl, MgCl2, NaCl, CaSO4 and
K2SO4. The wide spatiotemporal variation of EC in the cultivated
land in both seasons demonstrates that soil salinity is
controlled mainly by seawater intrusion and anthropogenic
factors such as the application of salt-rich water which is
directly pumped from the drainage ditches. Seawater intrusion
provides the affected soil with elevated contents of Ca2+, Cl−,
K+, Mg2+, Na+ and SO4
2−. Classification of the soils by using
criteria given by the literature is discussed. Practices to prevent,
or at least ameliorate, salinization in the cultivated land
of Agoulinitsa district are proposed.
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El Mandour, A., El Yaouti, F., Fakir, Y., Zarhloule, Y., & Benavente, J. (2007). Evolution of groundwater salinity in the unconfined aquifer of Bou-Areg, Northeastern Mediterranean coast, Morocco. Environmental Geology, 54(3), 491–503.
Abstract: The Bou-Areg plain in the Mediterranean coast at the North-eastern of Morocco is characterized by a semiarid climate. The aquifer consists of two sedimentary formations of Plio-quaternary age: the upper formation of fine silts and the lower one of coarse silts with sand and gravels. The aquifer is underlain by marly bedrock of Miocene age that dips toward the coastal lagoon of Bou-Areg. The
hydrodynamic characteristics vary between 10–4 and 10–3 m/s; and transmissivities range between 10–4 and 10–1 m2 /s. The general direction of flow is SW to NE, toward the lagoon. The aquifer is crossed by the river Selouane, which also ends in the lagoon. The groundwater is characterized by a high salinity that can reach 7.5 g/l. The highest values are observed in the upstream and in the downstream sectors of the aquifer. The temporal evolution of the physicochemical parameters depends on the climatic conditions and
piezometric variations. The analysis of the spatio-temporal distribution of the physico-chemical parameters suggests different sources of groundwater salinization: the seawater intrusion, the influence of marly gypsum-bearing terrains, and the influence of anthropogenic products as the agricultural fertilizers, which cause great nitrate concentrations that vary between 80 and 140 mg/l.
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Schmittner, K. - E., & Giresse, P. (1999). The impact of atmospheric sodium on erodibility of clay in a coastal Mediterranean region. Environmental Geology, 37(3), 195–206.
Abstract: Heavy rainfalls, between 25 and 100 mm·h–1, were simulated on Pliocene/Quaternary sediments. To reproduce the heterogeneity of natural environments, 231 small plots of various sizes (between 2.5 and 3.5 m2; mean: about 3 m2) were used. The duration of all simulations was 1 h. We used water that had been collected during natural rainfall. The concentration of clay particles in the sheet wash depended upon the concentration of dissolved sodium in the wash (for about 42%) and of the sheet wash quantity (for about 37%). Under natural water conditions colloidal matter, like clay minerals, is charged negatively and therefore is destabilized by metal cations such as in the case of Na+. Results suggest that relatively higher concentrations of montmorrillonite were related to higher concentrations of sodium as opposed to illite and kaolinite. Microflakes of up to 25 μ were observed to vary between face-to-edge and face-to-face modes (competition between protons and other cations). The concentration of dissolved sodium (Na+) in the runoff water depends on water and sodium balances such as atmospheric input, infiltration, evaporation and surface water runoff. The reduction of vegetation cover increases the amount of salt and amorphous matter in/on the topsoil between heavy rainfall generations. The best predictor to explain montmorillonite, illite and kaolinite in % of mineral clay-sized matter in the surface water runoff (sheet wash) is the percentage of each clay mineral in the topsoil. As opposed to illite and kaolinite, more sheet wash indicate for montmorillonite relatively higher concentrations in the wash. The results of model simulations were confirmed on different field plots of about 1 ha and small catchments during natural heavy rainfall events. Models can also be used to understand and to better simulate sheet, rill and gully erosion, micropedimentation; and pedimentation.
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Demirel, Z., & Güler, C. (2006). Hydrogeochemical evolution of groundwater in a Mediterranean coastal aquifer, Mersin-Erdemli basin (Turkey). Environmental geology, 49(3), 477–487.
Abstract: In this study, hydrogeologic and hydrochemical information from the Mersin-Erdemli groundwater system were integrated and used to determine the main factors and mechanisms controlling the chemistry of groundwaters in the area and anthropogenic factors
presently affecting them. The PHREEQC geochemical modeling demonstrated that relatively few
phases are required to derive water chemistry in the area. In a broad sense, the reactions responsible for the hydrochemical evolution in the area fall into four categories: (1)
silicate weathering reactions; (2) dissolution of salts; (3) precipitation of calcite, amorphous silica and kaolinite; (4) ion exchange. As determined by multivariate statistical
analysis, anthropogenic factors show seasonality in the area where most contaminated waters related to fertilizer and fungicide applications that occur during early summer season.
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Kim, Y., Lee, K. - S., Koh, D. - C., Lee, D. - H., Lee, S. - G., Park, W. - B., et al. (2003). Hydrogeochemical and isotopic evidence of groundwater salinization in a coastal aquifer: a case study in Jeju volcanic island, Korea. Journal of Hydrology, 270(3), 282–294.
Abstract: In order to identify the origin of saline groundwater in the eastern part of Jeju volcanic island, Korea, a hydrogeochemical and isotopic study has been carried out for 18 observation wells located in east and southeast coastal regions. The total dissolved solid contents of groundwaters are highly variable (77–21,782mg/l). Oxygen, hydrogen, sulfur, and strontium isotopic data clearly show that the saline water results from mixing of groundwater with seawater. Strontium isotopic compositions and Br/Cl and I/Cl ratios strongly suggest that the source of salinity is modern seawater intrusion. Hydrogeochemical characteristics based on bivariate diagrams of major and minor ions show that changes in the chemical composition of groundwater are mainly controlled by the salinization process followed by cation-exchange reactions. The highly permeable aquifers at the east coastal region are characterized by low hydraulic gradient and discharge rate and high hydraulic conductivity as compared with other regions. These properties enhance the salinization of groundwater observed in the study area. Based on the Cl, Br, and δ18O data, seawater was determined to have intruded inland some 2.5km from the coastline. Considering the poor correlation of sampling depth and Cl concentrations observed, the position of seawater-freshwater interface is not uniformly distributed in the study area, due to heterogeneities of the basaltic aquifers.
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