Progress of caesium 137 in the human body:
The activity of caesium 137 in the human body has been continuously monitored by the Mol laboratory in Northern Belgium for the past half century. Despite being far removed from the sites of nuclear tests and of the Chernobyl accident, we can see very clearly the peaks in activity caused by the tests and, at a quarter of the magnitude, the peak caused by Chernobyl. In both cases, the decay of caesium 137 found in the body is much quicker than the natural radioactive decay with a period of 30 years. Even though caesium slowly enters the soil, the rapid decay of the activity in humans has made it unnecessary for the Belgians to decontaminate their soil: as they could do through treating with Prussian blue.