PROBLEMES QUE POSE LE CONCEPT DU SEUIL DANS L'EVALUATION DU RISQUE RADIOACTIF

ABSTRACT In the case of exposure to ionizing radiation a distinction is generally made between somatic effects with a threshold, such as the acute radiation exposure syndrome, cataract and radiodermatitis, and random effects , such as cancer or radiation-induced changes, in the case of which the principle that a “no threshold level” exists, is applied. It is important to specify to what extent and for what purpose it has been assumed that the quantitative relationship between dose and effect is linear and can be used to evaluate the hazard or damage. Models other than the linear model could be considered but there is still no general agreement on the ideal representation of radiation hazards. The idea of a practical threshold must be considered, inasmuch as the pure and simple application of absolute linearity leads to an overestimation of the possible damage, the potential and random elements of which must be remembered. This is a calculated and theoretical risk and not a real effect connected with radiation exposure. The application of the “no threshold level” principle, as used in radiological protection, may be considered for other environmental pollutants, provided that the conditions under which the model was suggested and adopted as regards radiation exposure are borne in mind.