Resumen de Assessment of groundwater quality in the Garmez area (Southeastern Khuzestan province, SW Iran) for drinking and irrigation uses
The Garmez area is located in a semi-arid region with limited water resources. Therefore, maintaining the quality of groundwater and preventing it to be contaminated is of particular importance. In this research, five wells were sampled in the study area to investigate the quality of groundwater for drinking and agricultural purposes. Anions and cations of Cl−, SO42−, HCO3−, CO32−, NO3−, Ca2+, Mg2+, Na+ and K+, as well as important water quality factors including pH, EC and TDS were measured using titration, optical absorption spectroscopy, flame atomic emission spectrometry and drying methods. The analyzed data are compared with guidelines of the World Health Organization (WHO) and Iranian standard for drinking water, and with standard of the Food and Agricultural Organization of United Nations (FAO) for irrigation water. Mean values of anion and cation concentrations reveal that the groundwater in the study area is dominated by sulfate and calcium ions. The high correlation coefficients between TDS and dissolved ions, as well as the Gibbs’s diagram, suggest that rock weathering and evaporation–precipitation processes govern dominantly the chemistry of groundwater. The concentrations of major ions are higher than the permitted levels for drinking water, except for pH, chlorine, sodium and nitrate, indicating that most of the groundwater samples do not have a good quality for drinking purpose. All groundwater samples belong to the “Very hard” water class. According to the Schoeller's diagram, groundwater samples belong to a wide range of water quality classes from “Good” to “Unpleasant”. Most of the groundwater samples are of good quality when compared with the FAO standard for irrigation water, except that their calcium and potassium contents exceed the allowed limits. Based on the analysis of water quality indicators including SAR, PI, SSP, MAR, KR and RSC, most of the groundwater samples from the study area are of “Excellent” to “Good” quality classes, thus suitable for irrigation purpose. According to the Wilcox's diagram, groundwater samples fall in the C4S1 and C3S1 categories, reflecting that they are “Saline-suitable for irrigation with appropriate treatment”.
