干旱区生态环境知识资源中心

Albaji plain is located in the southwestern of Iran, containing groundwater with different chemical characteristics at various points. An understanding of the chemical origin of the groundwater provides insight into the interaction of water with the environment and contributes to a better resource management. To achieve this, 36 samples were collected from groundwater and river from northern part of the plain. The total dissolved solids (TDS), pH, water temperature, and electric conductivity (EC) were measured in the field by a portable multi-parameter analyzer. Major cations and anions were measured by using ion-chromatograph and titration with HCl. Resulted data was used to determine hydrochemical processes that occur in the aquifer media and ion context of waters using piper and combination diagrams, ion exchanges, and saturation indexes. Factor analysis as a statistical method was used to compare and verify the results. Results show that the Karkheh river has a positive impact on the quality of groundwater in the northern part of the aquifer. However, groundwater quality is brackish to high saline, and chemical composition of all samples highly depends on sodium and chloride. The ions in the groundwater are concluded to be mainly from dissolving evaporates, consistent with the dry climate in the region, whereas the ions in the river are mainly from rock weathering. Furthermore, other parameters such as rock-water interaction, mixing, irrigation water, sedimentation basin condition, and hydrogeochemical processes such as dissolution-crystallization and ion exchange are controlling the groundwater chemistry.