The general public's concerns regarding the quality of the environment, and the risks to which it is exposed, have been fuelled by several health crises illustrated in the nuclear domain by the accident in Chernobyl in 19861. Following this disaster, caesium 1372 released in large quantities into the atmosphere, was detected in abnormal levels in the food chain over 20 years later.
The consequences of chronic exposure to low concentrations of caesium 137 have not been fully elucidated. Some studies carried out on populations living in the contaminated areas suggest significant health repercussions and the onset of non-cancerous diseases. Reproduction and neurological disorders have been reported in the population residing in the immediate vicinity of the Chernobyl plant (Kryzhanovskaya, 1997; Goncharov et al ., 1998; Yablokov, 2009).
An increase in the frequency of electrocardiography and blood pressure disorders has also been reported in children living in the contaminated regions (Bandazhevskaya et al., 2004). It is nevertheless very difficult to make a direct link between the diseases observed and the levels of caesium 137 recorded in subjects living in these areas. The question therefore remains as to whether caesium 137 is solely responsible for the onset of these disorders. Given the lack of sufficiently relevant data in humans and animals concerning its effects at low doses, the IRSN has launched a series of experimental studies within the framework of the ENVIRHOM-Santé programme. The aim of these studies is to determine whether the chronic ingestion of caesium 137 alone could be responsible for the biological and clinical effects observed in the populations living in the contaminated regions.
The purpose of the first studies, carried out in an animal model (adult rat), was to describe the effects of caesium 137 on the central nervous system (Lestaevel et al., 2006; 2008), and the cardiovascular (Gueguen et al., 2008) and digestive systems (Dublineau et al., 2007) as well as on the principal metabolisms such as vitamin D (Tissandié et al., 2006; 2009), cholesterol (Souidi et al., 2006) and steroidal hormones (Grignard et al., 2008; 2010). The animals were contaminated by ingesting water with a concentration of 6500 Bq.L-1 caesium 137. Thus the dose ingested per animal, per day, corresponded to a post-accident environmental dose comparable to that detected in the area close to Chernobyl (Handl et al. 2003). The results show subtle yet significant changes in several physiological systemsThe question arising from these essentially genic effects is, whether the molecular changes are the precursors of the onset of a disease that can be observed at clinical level, or whether they instead reflect the ability of the body to adapt to this chronic exposure.