RADON AS A NATURAL TRACER TO STUDY TRANSPORT PROCESSES IN A KARST SYSTEM - AN EXAMPLE IN THE SWISS JURA

Several observations we have made during the last few years show that infiltrating rainwater does not simply dilute the radon in an aquifer. High radon concentration in limestone caves, radon peaks in spring waters after storms and a positive correlation between radon and discharge for different Swiss springs sampled monthly for 2 years rather show that infiltrating rainwater takes up a considerable amount of radon during its passage through permeable layers at shallow depth. The radon signal from these layers is most clear in waters emerging from a karstic aquifer. These results show that most radon in the spring water stems from layers covering the aquifer.