Cytogenetic damage analysis in mice chronically exposed to low-dose internal tritium beta-particle radiation

Abstract of the article in Oncotarget, 2018, 9(44), p. 27397-27411

Authors:

Institut de Radioprotection et de Sûreté Nucléaire, IRSN, Pôle Santé et Environnement, Direction de la Santé, Fontenay-aux-Roses, France

• Sandrine Roch-Lefèvre
• Eric Grégoire
• Cécile Martin-Bodiot
• Amélie Fréneau
• Laurence Roy
• Mohamed Benadjaoud

Radiobiology and Health, Canadian Nuclear Laboratories, Chalk River, Ontario, Canada

• Matthew Flegal
• Melinda Blimkie
• Laura Bannister
• Heather Wyatt
• Nick Priest
• Dmitry Klokov

Institut de Radioprotection et de Sûreté Nucléaire, IRSN, Direction des Affaires Internationales, Fontenay-aux-Roses, France

• Jean-René Jourdain

Department of Biochemistrty, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada

• Dmitry Klokov

Present address at: Autonomous University of Barcelona, Faculty of Biosciences, Cerdanyola del Vallès, Spain

• Joan-Francesc Barquinero

Abstract:

This peer reviewed research article describes the results of the cytogenetic damage experiments 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. Mice were exposed to gamma radiation, 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) for 1 or 8 months. The cytogenetic damage (DNA damage) was measured in bone marrow and peripheral blood lymphocytes (PBL) in order to assess the dose response and the relative biological effectiveness (RBE). The main conclusions were:

• Neither tritium nor gamma radiation produce increases in cytogenetic effects in bone marrow.
• Increases in DNA damage of PBLs due to chronic OBT exposure were observed (1,000 kBq/L and 20,000 kBq/L), but not at 10 kBq/L, the World Health Organization (WHO) limit.
• The RBE of OBT (endpoint: chromosome aberrations) is estimated at being significantly higher than 1 below cumulative doses of 10 mGy.

While the DNA damage potential of low doses of tritium (largely due to OBT) may be higher than estimated, no significant increase in DNA damage was measured at the WHO limit of 10 kBq/L. Thus, this study supports the WHO limit and therefore the Canadian guideline of 7 kBq/L for tritium in drinking water. This study was partly funded by the Canadian Nuclear Safety Commission and is part of a series of articles (Bannister et al, 2016; Priest et al, 2017; Guéguen et al, 2018) that have been and will be published soon.

For more information about tritium, please visit: CNSC.