Biokinetic data and models for occupational intake of lanthanoids

Abstract

Purpose: This paper reviews data related to the behavior of the lanthanoid elements (lanthanum through lutetium, atomic numbers 57–71) in the human body and proposes biokinetic models for internally deposited radio-lanthanoids in workers.

Materials and methods: Published data on the following topics are reviewed and analyzed: Physico-chemical properties of the lanthanoids as indicators of the potential behavior of these elements in body fluids; the concentrations of the stable lanthanoids in the environment and human body; and results of biokinetic studies of radio-lanthanoids in human subjects and laboratory animals. Respiratory and systemic biokinetic models and gastrointestinal absorption fractions are developed or selected in an effort to represent the typical behavior of lanthanoids in adult humans.

Results and conclusions: Generic (element-independent) absorption rates from the respiratory and alimentary tracts to blood and systemic biokinetic models are proposed. The systemic models are largely generic but include some element-specific parameter values to reflect regular changes with ionic radius in certain aspects of the behavior of the lanthanoids, particularly fractional deposition in liver and bone and early removal in urine.

Keywords::

• Lanthanoids
• lanthanides
• radionuclides
• biokinetics
• models
• workplace
• exposure

Acknowledgements

The work of the first author was sponsored by the Office of Radiation and Indoor Air, U. S. Environmental Protection Agency (EPA), under Interagency Agreement DOE No. 1824 S581-A1, under contract No. DE-AC05-00OR22725 with UT-Battelle. The submitted manuscript has been authored in part by a contractor of the U.S. Government under contract DE-AC05-00OR22725. Accordingly, the U.S. Government retains a nonexclusive, royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for U.S. Government purposes.

Declaration of interest

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