222Rn in Greek spa waters: correlation with rainfall and seismic activities

In our previous research, the natural radioisotopes (including 222Rn) present in the waters of the Greek spas Ikaria, Kamena Vourla, and Loutraki, were determined by gamma-spectroscopy, laboratory method. Large variations of 222Rn were found in different samples from the same spa. In order to explain these variations, the effect of rainfall before the sampling date was examined. It was concluded that rainfall decreased (or drought increased) the 222Rn concentrations in most cases. The explanation for the exceptions may be the effect of earthquakes. Characteristics considered include time, depth, magnitude, and distance of the epicenters from the spa. From the results, it can be concluded that the earthquakes increased 222Rn concentrations.