Terrestrial radiation comes from the natural radioactive substances which exist in various concentrations everywhere on earth. The dose rate resulting from Terrestrial radiation depends on the geological formations of the subsoil and therefore varies from one location to another. In Germany, an average external radiation dose of 0.5 mSv per year results due to Terrestrial radiation; in some parts of Brazil and India these values are ten times higher.

Area

Average effective dose mSv/year

Max. absorbed dose outdoor mGy/year

Germany

0.4

5

India: Kerala, Madras

4

50

Brazil: Espirito Santo

6

800

Iran: Ramsar

6

850

radiation dose due to Terrestrial radiation in various areas