Globally, the studies carried out at the IRSN have shown that the chronic ingestion of caesium 137 can trigger biological effects on certain major physiological functions.
In most cases (central nervous system, digestive system and steroid metabolism) these effects remain limited and do not trigger disease onset. As regards the cardiovascular system, the results obtained are an initial indication of the potential effects of caesium 137, although the effects observed contradict those observed in an earlier study (Bandazhevsky, 2003). In fact, our study highlights a reduction in arterial pressure in contaminated rats whereas hypertension was observed in Belarus children. In addition, no cardiac arrhythmia was observed in our animals.
The EPICE programme1 should provide some answers. In the case of haematopoietic and immune systems, the absence of any observed effect suggests that the model used must develop by applying experimental conditions that resemble the post-accidental situation more closely. Changes in the model must therefore include the use of radionuclide combinations typical of those detected in the food of populations living in contaminated areas and also increase the quantity of radionuclides ingested on a daily basis by the animals.
Thus laboratory studies are currently underway on strontium 90, which was also released into the atmosphere at the time of the Chernobyl accident. Its physical period of 28 years means that it can still be detected, albeit at much lower concentrations, in the food of populations living in contaminated regions (Cooper et al., 1992, Handl et al., 2003). Finally, the results of this research programme on a post-accidental situation model should lead to a more realistic evaluation of the risks to human health associated with the chronic ingestion of low concentrations of radionuclides.