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Sources of salinity and boron in the Gaza strip: Natural contaminant flow in the southern Mediterranean coastal aquifer
Author(s) -
Vengosh Avner,
Kloppmann Wolfram,
Marei Amer,
Livshitz Yakov,
Gutierrez Alexis,
Banna Mazen,
Guerrot Catherine,
Pankratov Irena,
Raanan Hadas
Publication year - 2005
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2004wr003344
Subject(s) - aquifer , groundwater , geology , soil salinity , saline water , salinity , evaporite , groundwater flow , hydrology (agriculture) , gypsum , hydrogeology , halite , carbonate , geochemistry , sedimentary rock , chemistry , oceanography , paleontology , geotechnical engineering , organic chemistry
Salinization in coastal aquifers is a global phenomenon resulting from the overexploitation of scarce water resources. The Gaza Strip is one of the most severe cases of salinization, as accelerated degradation of the water quality endangers the present and future water supply for over 1 million people. We investigate the chemical and isotopic ( 87 Sr/ 86 Sr, δ 11 B, δ 18 O, δ 2 H, and δ 34 S SO4 ) compositions of groundwater from the southern Mediterranean coastal aquifer (Israel) and the Gaza Strip in order to elucidate the origin of salinity and boron contamination. The original salinity in the eastern part of the aquifer is derived from discharge of saline groundwater from the adjacent Avedat aquitard (Na/Cl < 1, 87 Sr/ 86 Sr ∼ 0.7079, and δ 11 B ∼ 40‰). As the groundwater flows to the central part of the aquifer, a dramatic change in its composition occurs (Na/Cl > 1, high B/Cl, SO 4 /Cl, and HCO 3 , 87 Sr/ 86 Sr ∼ 0.7083; δ 11 B ∼ 48‰), although the δ 18 O‐δ 2 H slope is identical to that of the Avedat aquitard. The geochemical data suggest that dissolution of pedogenic carbonate and gypsum minerals in the overlying loessial sequence generated the Ca‐rich solution that triggered base exchange reactions and produced Na‐ and B‐rich groundwater. The geochemical data show that most of the salinization process in the Gaza Strip is derived from the lateral flow of the Na‐rich saline groundwater, superimposed with seawater intrusion and anthropogenic nitrate pollution. The methodology of identification of multiple salinity sources can be used to establish a long‐term management plan for the Gaza Strip and can also be implemented to understand complex salinization processes in other similarly stressed coastal aquifers.