Internal exposure of the staff involved in the cleanup after the accident at the Chernobyl nuclear power plant in 1986.

This article presents the results of our work from 1987 to 1994 on the reconstruction of internal exposure of the witnesses to the Chernobyl accident with respect to inhalation of airborne particles of nuclear fuel. Our results eliminate the hypothesis that inhalation intake of radioactive aerosols was a considerable pathway of exposure for staff at the Chernobyl nuclear power plant. It would conceivably lead to a nonuniform dose distribution in the body. Under that condition, actual equivalent doses in some organs, e.g., in lungs and in the wall of the lower large intestine are much higher than the actual effective dose. Therefore it is impossible to correctly assess the health risk for certain cohorts of the Chernobyl accident witnesses if the inhalation pathway is neglected. In that case not only the actual effective dose, but the actual equivalent doses too play a role in radiological measurement, when evaluating the hazard for less-exposed accident witnesses. That conclusion is of great importance to radiation protection policy, the planning of epidemiological studies and the carrying out of medical remedial actions for the different cohorts of accident witnesses. The findings should be taken into consideration in planning protective measures and in assessing health effects following the Chernobyl accident.