Consequences of atmospheric contamination by radioiodine: the Chernobyl and Fukushima accidents.

ABSTRACT

PURPOSE: After the accidents of nuclear power plants at Chernobyl and at Fukushima, huge amounts of radioactive iodine were released into the atmosphere. METHODS: We reviewed data on the health consequences of these accidents with a focus on thyroid consequences. RESULTS: Among the 2 million children who were living in highly contaminated regions in Belarus, Ukraine and Russia, 7000 cases of thyroid cancer had occurred in 2005. This is the most significant radiation-induced consequence of the Chernobyl accident. The increased incidence of thyroid cancer observed in adult population who lived in these highly contaminated regions is at least in major part related to screening and it is not possible to individualize among these thyroid cancers those that are potentially caused by radiation exposure. For populations who lived outside these regions at the time of the accident, there is no detectable consequence of the radiation exposure on the thyroid gland. Among children who lived nearby the Fukushima power plant in 2011, there is currently no evidence of an increased incidence of thyroid cancer. Ultrasonography screening in these individuals detected a number of thyroid cancers that are probably not related to the accident. Because thyroid cancer is frequent, studies have been carried out to distinguish radiation-induced from their sporadic counterparts, and genomic signatures might be helpful. CONCLUSIONS: The consequences of the Chernobyl accident clearly demonstrate that populations living nearby a nuclear power plant should be protected in case of accident by sheltering, food restrictions and prophylaxis of thyroid irradiation by potassium iodine administration, if the predicted estimated dose to the thyroid gland of children might be >50 mGy. These countermeasures should be applied in priority to children, adolescents and pregnant women; they are safe and effective.