Hydrogeological Controls of Radon in a few Hot Springs in the Western Ghats at Ratnagiri District in Maharashtra, India

Geological structures (faults, fractures and weak zones) and high heat flow in geothermal areas allow easy passage for release of radon gas to the atmosphere. Radon is constantly transported from the Earth's interior and vented out through exhalation points at permeable fault zones. ²²²Rn concentrations were measured in a few hot springs and nearby groundwater using RAD7 at Tural and Rajwadi, Ratnagiri district, Maharashtra. The ²²²Rn concentrations in the hot springs vary from 1087 7± 132 to 1655 ± 177 Bq/m³ at Tural and from 152 ± 67 to 350 ± 82 Bq/m³ at Rajwadi. Groundwaters from wells within a radius of 200 m around the geothermal fields have radon concentration between 1087 ± 132 and 5445 ± 337 Bq/m³. We have assessed the radon activity in the vicinity of the hot springs to understand their hydrogeological control, origin of heat source and possible effect on the tourist and the human population residing nearby.