Distribution of Arsenic in Hot Springs and Geothermal Wells in Sabalan Geothermal Field, N-W Iran

Abstract

Sabalan geothermal field is a high temperature area under development which is rich in geothermal manifestation at the surface with a temperature in the range of 25–85°C. Most of the hot springs have their outlet into the river. Distribution of Arsenic in geothermal waters in Sabalan area has been studied. High As concentration (up to 3500 µg/l) was recorded in geothermal well fluids with sodium-chlorate type.Concentration of As in hot spring waters in the range of 0.8-890 µg/l. Concentrations of As are higher in the chloride hot springs than in the acid-sulfate features and increase with increasing temperature and salinity. Positive correlation As with Cl has been detected that validate for most geothermal fields in the world. In all samples concentration of As exceed the WHO limit for drinking water (10 µg/l) except one sample from Agh-su hot spring.