The applications of ionizing radiation also make this type of discovery possible.
The physicists who carried out the study used the small nuclear reactor at the University of Pavia, and applied techniques created for the project called 'Cuore' (heart), which is being developed in the Italian INFN laboratories in Gran Sasso.
The research, the results of which are published in the journal Il Nuovo Saggiatore, was carried out on hair samples taken during different stages of Napoleon Bonaparte's life, from his childhood in Corsica, through his exile on the island of Elba, to the day of his death (May 5, 1821) on the island of Santa Elena, as well as the day after his death.
Samples taken from the King of Rome (Napoleon's son) in the years 1812, 1816, 1821 and 1826, and samples from the Empress Josephine collected after her death in 1814, were also analysed. The hair samples were provided by the Museo Glauco-Lombardi Parma, the Malmaison Museum in Paris and the Napoleonic Museum in Rome. In addition to these “historical” hair samples, ten hairs from living people were examined for comparison purposes.
The hairs were placed in capsules and introduced into the core of the Pavia nuclear reactor. The technique used is known as “neutron activation”, which has two important advantages: it does not destroy the sample and it offers extremely accurate results even on samples with a very small mass, such as human hair samples.
Using this technique, the researchers established that all the hair samples contained traces of arsenic. The researchers decided to test with arsenic in particular since for a number of years historians, scientists and writers have hypothesized that Napoleon was poisoned by guards during his imprisonment in Saint Helena after the Battle of Waterloo. .
The examination produced surprising results. First, the level of arsenic in all hair samples from 200 years ago is 100 times higher than the average level detected in samples from people alive today. In fact, the emperor's hair had an average arsenic level of about 10 parts in a million while the arsenic level of hair samples from people alive today was about one-tenth in a million. In other words, at the beginning of the 19th century, arsenic present in the environment was evidently ingested in amounts that are now considered harmful.
The other surprise lies in the discovery that there are no significant differences in Napoleon's arsenic levels as a child and during his last days on Saint Helena. According to the researchers, especially the toxicologists who participated in the study, it is clear that this is not a case of poisoning, but the result of a constant absorption of arsenic.