Estimation and management of risk for lung cancer induced by radon progeny

Estimation and management of risk for lung cancer induced by radon progeny. Radon is a radioactive gas released form soils and materials containing radium. Once inhaled in the respiratory tract, its decay products irradiate the tissues and provoke a risk of cancer. The estimation of this risk is carried out through an epidemiologic or a dosimetric approach. The former uses data on the mortality of miners who were exposed to radon. Then the results are extrapolated to the general population. More recently, some studies tried to estimate the risk directly on the general population. The latter approach tries to compute the rate of conversion between the radon concentration in the indoor environment and the dose absorbed by the respiratory tract. The risk of cancer is estimated through a coefficient which has been inferred from studies on the Hiroshima and Nagasaki survivors. The risk management requires the definition of general principles and of a set of recommendations. In the past, the ICRP stated that risks provoked by natural sources of irradiation should not be taken into consideration. Since 1984, it has changed its mind and limits of acceptability concerning radon concentration in dwellings have been defined. We should stress that the cancer risk estimations are tainted by uncertainties. 'Experts judgements' play an important part. On the other hand, 'value judgements' are essential in the field of risk management. Obviously, it is a problem which has a trans-disciplinary character and which rises the question of the relationship between science and society. (authors)