Assessment of occupational doses from internal contamination with 241Am

A group of workers with occupational intakes of 241Am, which occurred a long time ago, has been followed for some time. Results of in vivo measurement and bioassay of excreta are compared with the values predicted by the ICRP Publication 78 model. The observed skeletal content is, as a rule, higher than the predicted one. The ratio of excreted activity in urine to that in faeces is in very good agreement with the model prediction. Another group of workers from a waste management department, who were internally contaminated in July 2001, has also been followed. In some cases, there is quite a large difference in calculated intake between excretion by urine and that by faeces. The contaminant was presumably the same as that in the group of workers with old intakes, but its physical and chemical form could be influenced by a fixating lacquer used to prevent the spread of contamination.