Absorption of americium compounds in the respiratory tract

Abstract

Purpose: To improve the dosimetry of incorporated americium (Am) and to contribute to radiation protection by characterizing the absorption kinetics of inhaled Am compounds.

Material and methods: In vitro dissolution tests, animal experiments and human contamination cases published in the literature were reviewed. The data were analyzed with biokinetic models consistent with the current publications of the International Commission on Radiological Protection.

Results: Material-specific dissolution parameter values with consequent assignment to absorption Types are proposed as well as representative central values for the different chemical forms of Am.

Conclusions: The absorption of Am oxide is consistent with the moderate absorption Type M while Am nitrate appears more soluble. Am associated with plutonium oxide usually follows its slow absorption Type S. However, the large variability observed stresses the value of investigating the specific absorption kinetics for Am compounds which represent a significant risk of internal exposure.

Keywords::

• Americium
• respiratory tract
• lung
• HRTM
• inhalation
• absorption
• solubility
• dissolution
• kinetics

Acknowledgements

The authors are grateful to Dr Ray Guilmette for his insight into the americium bound fraction and to Dr Kim Eunjoo for initiating the analysis of americium studies during her stay in our group.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.