Radon occurrence in soil–gas and groundwater around an active landslide

This paper presents the results of investigation of radon levels in the soil–gas and groundwater of Uttarkashi, India within the distance of 5 km in vertical and horizontal directions from the landslide of Varunawat hill. Radon release from the soil and groundwater was found higher than the normal values. Radon concentration in groundwater over and around the landslide was found to vary from 0.51 to 86kBqm-3. The soil–gas radon concentration was found to vary from 219 to 3kBqm-3 along the slope of landslide. Radon exhalation rate in collected soil samples was found to vary from 2.28×10-52.28×10-5 to 9.01×10-5Bqkg-1h-1. Radon values were not found correlated with major and trace element contents in the upper soil of the area, which indicate that the migration of radon from deeper part of the earth along with landslide contribute to the surface radon concentration. Recorded values show a close association with local geology and Varunawat eruptions.