Assessment of Hydrochemical Characteristics and Groundwater Suitability for Drinking and Irrigation Purposes in Garmsar Plain, Iran

Groundwater is an important water supply for irrigation and drinking purposes in semi-arid regions. In the Garmsar Plain, Iran, groundwater has severely deteriorated during recent years due to human activities and environmental changes. Hence, the main purpose of the current research is to investigate the chemical processes that control hydrochemistry and assess the groundwater quality to determine its suitability for irrigation and drinking uses and potential human health risks. Analysis results of the groundwater samples revealed that the most common water type is the sodium chloride type (82%) in the Garmsar Plain, followed by the mixed Ca-Mg-Cl type (18%). The main processes that contribute to groundwater chemistry are the dissolution along the flow path, evaporation, rock water interaction, ion exchange, and the mixing processes. According to the Irrigation Water Quality Index (IWQI), 51% of samples represent a severe restriction category and the remaining 49% constitute a high restriction class which reveals moderate to high salt tolerance, indicating that salt plants under some irrigation conditions can be cultivated in the Garmsar Plain. Based on human health considerations, 33%, 31%, 46%, 44%, 95%, and 77% of the groundwater samples are classified as poor water because of their high concentrations of Ca2+, Mg2+, Na+, HCO3-, Cl-, and SO42-, respectively. Drinking this water may cause a risk to human health, therefore management strategies are required for sustainable groundwater quality protection in the Garmsar Plain before using it for irrigation and drinking purposes.