Space-time hydrochemical variations and water quality of Euphrates river

The study of hydrochemical variations and water quality assessment of the Euphrates river was performed in eight water points and two rainfall sites, during a boundary condition of rainy weather. The hydrochemical variations are determined, using the analysis results of 14 physico-chemical variables in 26 water samples. The study examined the depletion and attenuation processes during a rainstorm and the re-enrichment of the concentrations after rain event by using the statistical information of the major ions (HCO3−, SO4−2, Cl−, Mg+2, Ca+2, Na+, and K+). The lowest values of Cl−, SO4−2 were observed (94.7 and 202 mg/L) during the rain storm period, while the highest value of Cl− (114 mg/L) and SO4−2 (254 mg/l) were recorded before and after rain storm, respectively. The values K+, Na+, Mg+2, and Ca+2 are (3.3, 73.5, 35.8, and 83 mg/L). The hydrogeochemical indices confirm the role of irregular processes of chemical balance resulting from the propagation of mixing, ion exchange, and water-rock interaction between river and rainstorm water during high flow period. The results that derived from water quality assessment indicate that there are no serious geogenic pollution cases, with the absence of thermal pollution sources which is degradation of water quality by any process that changes ambient water temperature such as domestic sewage, hot springs, and soil erosion that forms serious impact on the biological diversity of the Euphrates water system. The total dissolved solids (TDS) and electrical conductivity (EC) measurements ranging from 484 to 778 mg/L and from 770 to 985 μScm−1, respectively. © 2021, Saudi Society for Geosciences.