Mapping radon risk in Ireland using airborne geophysics

Radon is a radioactive element that occurs naturally in rocks and soils as a daughter product of Uranium 238 and Radium 226. Exposure to high concentrations is known to increase the risk of lung cancer (UNSCEAR 2009; WHO,... [ view full abstract ]

Radon is a radioactive element that occurs naturally in rocks and soils as a daughter product of Uranium 238 and Radium 226. Exposure to high concentrations is known to increase the risk of lung cancer (UNSCEAR 2009; WHO, 2009). Accurate mapping of its occurrence can help identify households that are at risk of exposure to high radon levels and highlight areas where buildings require radon mitigation measures.

The Tellus Project is a geochemical and airborne geophysical survey programme, managed by the Geological Survey of Ireland (GSI). As part of the airborne geophysical survey, gamma-ray spectrometry data is employed to measure concentrations of potassium, thorium and uranium in soils and rocks. Using this data in conjunction with groundwater datasets (aquifer classification and vulnerability) can help model radon risk potential. This is different to geogenic radon modelling carried out in other counties where the source rather than the pathway is the main controlling variable analysed. GSI’s models have been constructed and evaluated using indoor radon measurements made available by the EPA. They use multivariate linear regression based on 1km grid squares. The airborne and geological data is assigned to grid squares and correlated with existing indoor radon measurements. Good agreement has been found and new detailed maps of radon risk produced. New anomalous zones have been found and are subject to further investigation. An improved way of communicating these findings from the model and highlighting the risk of radon exposure are also being discussed with the EPA.