Two and a half years of natural radioactivity ...
. The nuclear atmospheric tests have dispersed huge quantities of radioactive elements, as has been shown by the estimates of the total activities of the main radioactive elements released. For reason of radioactive decline, the contaminations (in red) which still subsists 40 years after the end of these trials concerns tritium, carbon-14, strontium-90 and caesium-137. It is considered that humanity has been exposed to the equivalent of two and a half years of natural radioactivity as a result of these tests. (NB: the unity used for these very strong activities is the “etabecquerel”).
IN2P3