In vivo animal studies help achieve international consensus on standards and guidelines for health risk estimates for chronic exposure to low levels of tritium in drinking water

Abstract of the article in Environ Mol Mutagen 59(7): 586-594, 2018

Author(s):

¹Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-SAN, Fontenay-aux-Roses, France

• Yann Guéguen
• Isabelle Dublineau
• Marc Benderitter
• Christelle Durand
• Teni G. Ebrahimian
• Eric Grégoire
• Stéphane Grison
• Chrystelle Ibanez
• Audrey Legendre
• Philippe Lestaevel>
• Sandrine Roch-Lefèvre
• Laurence Roy
• Karine Tack
• Jean-René Jourdain

²Radiobiology and Health, Canadian Nuclear Laboratories, Chalk River, ON, Canada

• Nicholas D. Priest
• Laura Bannister
• Heather Wyatt
• Dmitry Klokov

³Canadian Nuclear Safety Commission, Ottawa, ON, Canada

• Julie Leblanc

⁴Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada

• Dmitry Klokov

Abstract:

In vivo animal studies help achieve international consensus on standards and guidelines for health risk estimates for chronic exposure to low levels of tritium in drinking water

This commentary summarizes the results achieved through the Studies on the Toxicity of Tritium: Effects of Low Dose Tritium and Gamma Radiations. The research was conducted collaboratively between the Canadian Nuclear Laboratories (CNL) and the Institut de Radioprotection et de Sûreté Nucléaire (IRSN), using the mouse as an experimental model. The different issues regarding the dosimetry of tritium exposure, and consequently, the worldwide variations relating to the regulatory standards for tritium in drinking water are discussed. Detailed results will be published in several peer-reviewed journals, and focus on the following five conclusions:

1. The biokinetics of tritiated water (HTO) and organically bound tritium (OBT, in this case, tritiated amino acids) (10 kBq/L, 1,000 kBq/L, 20,000 kBq/L) were found to be similar. This is in contrast to the International Commission on Radiological Protection (ICRP) models where greater OBT retention was expected.
2. OBT exposures produce a larger dose-related biological response than equivalent doses of gamma radiation (more so than HTO).
3. Neither HTO, nor OBT produced significant biological effects at the World Health Organization (WHO) guidance level of 10 kBq/L (equivalent to 0.01 mSv and ~0.1 mSv, 1 and 8 month exposure, respectively).
4. Some biological effects may be protective, while others, detrimental.
5. Biological effects observed were tissue-specific.

This paper highlights these conclusions and provides an overall description of their scientific meaning, as well as their significance on radiation protection. Collaborative large-scale animal studies, like this one, are important in achieving worldwide consensus on standards and guidelines for tritium in drinking water. This study and further follow-up experiments were partly funded by the Canadian Nuclear Safety Commission.