Assessment of hydrochemical evolution of groundwater and its suitability for drinking and irrigation purposes in Al-Khazir Gomal Basin, Northern Iraq

This study evaluates the groundwater suitability for drinking and agricultural purposes and assesses the hydrochemical evolution in Al-Khazir Gomal Basin, north of Iraq. Sixty groundwater samples and 10 river water samples were collected in the dry season (October) and wet season (April). The samples were analyzed to determine major and some minor ions, trace elements, and physicochemical properties. All surface and groundwater samples are considered as fresh water (TDS < 794 mg/L) and slightly vary in chemical composition. The abundance of the major ions is as follows: Ca2+ > Mg2+ > Na+ > K+ = HCO3 − > SO4 2− > NO3 − > Cl−. Interpretation of analytical data showed predominance, the water type of Ca–HCO3 and Ca–Mg–HCO3 indicated young and renewable groundwater. Total dissolved solid, total hardness, major ions, and trace elements are all within permissible limits of the potable and domestic purposes according to the European and WHO standards. The parameters of irrigation suitability showed that all of the samples are fit for irrigation purpose. Moreover, cluster and factor analyses were applied to the large data set (70 samples and 25 variables) to unravel the hidden relationships between the parameters, and to reveal the main factors affecting the water quality. The samples collected from the same well during the wet and dry season were clustered together indicating that the seasonal variability is negligible. Factor analysis showed that the rainfall leaching processes (recharge), carbonate minerals dissolution, aluminosilicate weathering, and ionic exchange are the dominant factors involved in controlling the groundwater chemical composition.