Top soil radioactivity assessment in a high natural radiation background area: The case of Vinaninkarena, Antsirabe-Madagascar

The village of Vinaninkarena, Antsirabe, Madagascar (47°02′40″E, 19°57′17″S) is located in a high natural radioactivity area. In order to evaluate the natural radionuclide content in soil, sampling was done on-site by the transect method (85 soil samples) and off-site through transects across and beyond the region (up to a range of 100 km), to determine the natural radioactivity variation within vs. outside the region, and to detect significant differences, taking into account spatial variability.