The release of radionuclides and their persistent presence in the environment1 can lead in the long term to external irradiation or internal contamination via the food chain or of drinking water for populations living in these contaminated areas. This raises scientific and society-led questions about the clinical repercussions of such exposures on public health. Research conducted on external irradiation at low dose levels has focused primarily on cancer-related risks and knowledge gleaned to date is still lacking in terms of the existence of biological effects and the possible onset of non-cancerous diseases.
This lack of knowledge is even more marked in the case of chronic exposure through internal radionuclide contamination. The effects following chronic exposure are, in fact, mostly extrapolated according to a theoretical model designed essentially on the basis of the clinical observations of survivors of Hiroshima and Nagasaki, who suffered acute exposure at high dose levels (CIPR, 2007). It is now acknowledged that the molecular, cellular and tissue processes triggered by both types of exposure (chronic exposure to low doses compared to acute exposure to high doses) are extremely different despite similarities in terms of the initial stages of energy absorption, ionisation and the rupture of biological molecules. Simple extrapolations do not, therefore, seem adequate to grasp the effects of low-dose chronic exposure based on data acquired in a acute exposure situation at high dose level. This lack of knowledge is even more marked in the case of chronic exposure through internal radionuclide contamination.