Studies on clearance of accidentally inhaled 125Sb aerosols in humans

Studies on the clearance of 125Sb oxide aerosols in human lungs have been carried out on seven accidental inhalation exposure cases. Follow up studies have been carried out from day one after the intake to about 2100 days post intake, Studies indicate that the biological lung clearance halftime of this material is more than 500 days. The retention in the lung after 180 days in all the seven cases is found to be more than 51% which is consistent with the present ICRP criteria of assignment to the present lung absorption Type S. Results of these studies suggest that the oxides of 125Sb should be removed from absorption Type M (earlier class W) where these are presently listed by ICRP and be placed in absorption Type S (earlier class Y). (author)