Digital Atlas of Natural Radiation

The human population is continuously exposed to ionizing radiation from several natural sources that can be classified in two categories:

  • Cosmic contribution: high-energy cosmic rays incident on the Earth's atmosphere and releasing secondary radiation
  • Terrestrial contribution: radioactive nuclides generated during the formation of the Earth and still present in the Earth's crust: mostly uranium and thorium radioactive families together with potassium (40K), which is a long-lived radioactive isotope of the elemental potassium. In most circumstances radon, a noble gas produced in the radioactive decay of the Uranium progeny, is the major contributor to the total dose.
The European Atlas of Natural Radiation

The European Atlas of Natural Radiation is a collection of maps displaying the levels of radioactivity caused by different natural sources in Europe.

The Atlas is intended to familiarise the public with the radioactive environment, to give a more balanced view of the annual dose that it may receive from natural radioactivity and to provide reference material and generate harmonised data for the scientific community. The overall goal of the Atlas is to estimate the annual dose that the public may receive from natural radioactivity, combining all the information from the different maps. Indeed, natural ionizing radiation is considered the largest contributor to the collective effective dose received by the world population.

The Atlas is developed and maintained by the Joint Research Centre of the European Commission.

Atlas Maps

    Thorium concentration in bedrock


    The European thorium concentration in bedrock* map displays the arithmetic mean (AM) of the concentration of thorium in bedrock within the geological unit. Geological units homogeneous in thorium content have been identified using OneGeology-Europe data ( Moreover the selection of the geological unit has been supported by lithostratigraphy, petrology and mineralogy knowledge as well as relevant geological literature. Data of thorium concentration in rock samples have been collected from scientific literature. These data have been used to estimate the average value of thorium concentration in bedrock for each geological unit. This map has been developed on a country-by-country basis and could easily be improved if more data were made available.

    *Bedrock is here defined as solid rock underlying loose deposits such as soil or alluvium.


    Braga R., Cinelli G., Tollefsen T., De Cort M. Bedrock U-Th-K signatures in the ongoing European Atlas of Natural Radiation. International Workshop on the European Atlas of Natural Radiation, Verbania, 9-13 November 2015. Download.

    Information about methodology: Manuscript in preparation

    Austria: List of references Download

    Belgium: List of references Download

    Estonia: List of references Download

    Hungary: List of references Download

    Luxembourg: List of references Download

    Netherlands: List of references Download

    Portugal: List of references Download

    Slovenia: List of references Download

    Spain: List of references Download

    Additional Information


    Last Modified: 26/04/2017

    Update frequency: Irregular