Health Canada's approach to manage risks to populations at risk during a radiological emergency

The approach that Health Canada uses to manage risks to individuals and to populations who might be exposed to ionising radiation is based upon the risk management paradigm. The paradigm differs little between an emergency and a non-emergency situations. In both events, technical experts assess the risk by determining the exposure to the source of radiation. They usually calculate the radiation dose and then assess the potential for any health effects. The initial technical assessments often use scoping calculations. The calculations for children recognise that they are smaller and have different metabolic rates and different behaviour from adults. However, most rigorous quantitative models for dosimetry do not differentiate between children and adults. The risk assessments that were conducted to evaluate the contamination of Canadians who were in London during the Litvenenko poisoning are a good example to illustrate this general approach. The scoping risk assessment concluded that the risks to children and adults were low. No Canadian children were exposed to polonium during this event and, to date, there have been no radiation emergencies in Canada where children have been exposed to a significant source of radiation. Therefore, the comparisons between theory and practice are very limited and conclusions are drawn from international experience and other incidents or sources of radiation exposure such as radon and medical exposures.