LAUSR

ABSTRACT This research investigated on the hydrochemistry and salt-fresh mixing of the groundwater in the aquifers nearby Sirjan salt playa near Sirjan city, Kerman province, Iran. Therefore, 62 groundwater samples were collected from Sirjan salt playa, Kheyrabad plain, Chahderaz plain and Golgohar mining area. Chemical diagrams, ion ratios, statistical method and mixing applied to hydochemical investigation. The water samples were then categorised into four water types; i.e. NaCl, Na-Ca-Cl, Na-SO4 and Ca-HCO3. The presence of salt playa in the area has led to the phenomenon of mixing between saline and freshwater. Saltwater intrusion occurred from 0.01 to 29% in the groundwater and it destroyed the quality of groundwater in the study area. Most percentages of intrusion were seen in Golgohar mine area and which is due to overexploitation of groundwater by dewatering process in the pit, where the saltwater intrudes from hard rock aquifer by upconing phenomena. Results showed that the actual concentrations of Na+ are less than expected concentrations; while for Mg2+ and Ca2+ their actual concentrations have been increased versus expected concentrations and it suggests cation exchange of Na+ by Mg2+ and Ca2+ in the aquifers of the study area.