Naturally Occurring Arsenic and Boron in Geothermal Systems and Their Health Effects: a Case Study From Turkey

Abstract

Human beings have benefited from geothermal energy for different uses since the dawn of civilization in many parts of the world. However, the highest concentrations of naturally occurring aqueous arsenic (As) and boron (B) are found in certain types of geothermal fluids, generally those related to faults and volcanic activity which have caused wide-ranging alteration from argillic type to silica type. The argillic alteration zones are typically enriched in sulfur in volcanic rocks. Also, epithermal systems, which have a high concentration of As in the form of realgar and orpiment along the fracture zones of metamorphic and carbonate aquifers. On the other hand, B can easily rise to the surface by hydrothermal activity or concentrate in residual magma fluids or coexisting liquid and gas phases depending on the geology. The concentration of As and B in geothermal fluids changes in each geothermal field because of the geological properties of the region. For example, the concentration of As in geothermal fluids ranges from 10 μg/L to 50 mg/L in different parts of world whereas the concentration of B ranges from 0.04 to 119 mg/L. This chapter describes the sources and behavior of As and its relationship to elements such as B and chlorine (Cl−) using data from the samples taken from boiling and warm hot springs and geothermal wells in different geothermal fields in Turkey to evaluate their environmental impacts. © Springer Nature Switzerland AG 2021.