Dissolution Parameters of Pu and Am After Inhalation Exposure of Rats to Different amounts of Mixed (U, Pu)O2 or Industrial PuO2

• Published in: The Annals of occupational hygiene 2002, Vol.46 (suppl-1), p.334-336
• Main Authors: Ramounet-Le Gall, B., Fritsch, P., Abram, M.-C., Grillon, G., Rateau, G., Delforge, J.
• Format: Article
• Language: English
• Subjects: dissolution parameters; lung clearance; plutonium oxide; U/Pu mixed oxides
• ISSN: 0003-4878; 1475-3162
• DOI: 10.1093/annhyg/46.suppl_1.334

We have measured dissolution parameters of Pu and Am after inhalation exposure to industrial PuO2 or (U, Pu)O2 containing 5% Pu (MOX) aerosols for different initial deep lung deposits (IDLD) in four rat groups. The parameters are those described in the simplest dissolution model of ICRP66. The mean IDLD values were 1.7 and 3.7 κBq for PuO2 and 1.5 and 6.5 κBq for MOX. Although gross lung pathologies occurred in the highest IDLD groups, no significant difference in lung clearance parameters were observed as compared with the lowest IDLD groups. This was due to important individual variation. Dissolution parameters were obtained by a linear correlation analysis between individual lung cumulative deposits and transfer to blood, which was estimated from femur retention. Dissolution of Pu was significantly increased in the highest IDLD groups. In the case of PuO2 the main altered parameter was the fast dissolving fraction (fr), whereas in the case of MOX it was the dissolution rate of the slow dissolving fraction (ss). In both cases the difference corresponded to a factor of about 2. Preliminary results on Am dissolution suggested a similar response but with differences near a factor of 3.