Source of 226Ra in Ramsar spring water, Iran: implication of water–rock interaction and stable isotopes

This study was carried out primarily to understand the hydrogeochemical processes controlling 226Ra anomalies in Ramsar area. Analyses revealed two types of water: (1) non-thermal Ca–HCO3 type and (2) thermal Na–Cl type, mainly meteoric hydrothermal origin, respectively. Non-thermal springs have higher concentrations U due silicate weathering. Thermal are characterized by high 226Ra, As, Fe, Li, Cs, Rb, Sr, Ba, B, Br−, F−, NO3−, PO43− SiO2 resulting from high-temperature water–rossck interaction mixing with fluids. manifestations an old system subsurface reservoir temperatures varying between 83 100 °C. Radium activity is negatively correlated pH positively TDS, Cl−, Ca, reflecting competitive ion effects alkaline-earth metals, complexing co-precipitation barite calcite. These thought be dominant factors mobility spring water.