Assessment of plutonium in lung for both chronic and acute exposure conditions

The assessment of plutonium oxide in the lungs of a specific group of workers in an Experimental Fuels Laboratory is done on a routine basis for chronic exposure and on demand following suspected incidents. This assessment is based on both direct and indirect methods. Such methods are briefly discussed and a summary of the results of the programme during the past five years is presented. Acute intakes, after the early clearance phase, appear to be removed from the lung according to a two-term exponential pattern; the intermediate phase is of the order of 30-day half period and the long-term phase has a half period in excess of 200 days. Chronic levels of activity in the lung, not associated with known intakes, were low. The correlations of data from air sampling, bioassay, nose blows, faeces and urine samples with direct lung counting are briefly discussed together with the accuracy of the procedure. (author)