Radioprotection 2026, 61( 2), 171 – 177 © N. Blanchin et al., Published by EDP Sciences 2026 https:// doi. org / 10.1051 / radiopro / 2025031
Available online at: www. radioprotection. org
ARTICLE
Survey following uranium contamination
N. Blanchin 1,*, R. Grare 1, Ch. Guy 2 and L. Halladjian 3
1 CEA, Service de Prévention et Santé au Travail, 13115 Saint-Paul-Lez-Durance Cedex, France. 2 CEA, Département des Services de Santé et Sécurité, 13115 Saint-Paul-Lez-Durance Cedex, France. 3 CEA, Service de Protection contre les Rayonnements, 13115 Saint-Paul-Lez-Durance Cedex, France.
Received: 13 June 2025 / Accepted: 7 September 2025
Abstract – Any discrepancy between the initially hypothesis of an occupational exposure and the additional information collected from the facility and the radiation protection team should lead the exploration of other issues. In this specific case, the hypothesis of occupational intake in Uranium was selected based on the biokinetic models but not validated by the examination of the workplace. Additional information on the worker’ s dietary habits helped us understand the origin of the radiotoxicological monitoring results for Uranium exceeding the commonly accepted thresholds for the non-occupationally exposed general population.
Keywords: Uranium / dose assessment / dietary intake / phosphoric acid / chemical form
1 Introduction
Uranium is a ubiquitous atom in the Earth’ s crust. It is thus naturally found in food and drinking water( Ministère de la Santé � France, 2011). It is absorbed into the blood, from which it is filtered by the kidneys and eliminated in the urine. This mechanism leads to detectable activities in the excreta of the general population not professionally exposed. Uranium in the blood also deposits in the bone( cortical and trabecular zones) and in the liver. Its concentration due to diet varies greatly depending on the place of residence and dietary habits( ICRP, 1995). The solubility of the compound is the predominant factor to know the target organ and predict its toxicity. Unlike soluble uranium compounds from ore processing, whose toxicity is chemical in nature and notably affects the kidney, oxide forms are less soluble and the toxicity is rather radiological, historically responsible for bronchopulmonary cancers in case of inhalation, in combination with radon( Métivier, 2001).
Uranium is the main compound of nuclear fuels based on fission. Monitoring of workers professionally exposed to uranium relies, in addition to surface and atmospheric monitoring at the workplace, on individual monitoring from radiotoxicological analyses of excreta( urine and feces). Thus, the result of a radiotoxicological analysis of uranium in a person professionally exposed to uranium depends on the dietary intake to which may be added an incorporation of professional origin( Blanchin et al., 2013; Davesne et al., 2014).
* Corresponding author: nicolas. blanchin @ cea. fr
This case illustrates the difficulty, in certain situations, of determining the professional or non-professional origin of a uranium activity detected in a worker’ s excreta. When these activities exceed the thresholds commonly accepted in the general population, it is necessary to be systematic in the investigation allowing to determine the conditions and parameters of incorporation.
2 Discovery of abnormal uranium contamination in a decontamination worker
Mr CC, a worker employed by a company specializing in cleanup operations related to nuclear decommissioning has been working on various installations at Cadarache site since 2009. He is subject to systematic alpha radiotoxicological monitoring due to the risk of exposure to plutonium, americium, and uranium at the different worksites where he operates. This worker exhibited, in April 2015 and February 2016, urinary excretion of uranium slightly above the environmental background level. Subsequent tests returned results below the detection limit( see Tab. 2)
In July 2016, a radiotoxicological analysis of 24-hour urine showed a value of 11 mBq, exceeding levels considered normal in the general population and attributed to dietary intake. The reference document " Surveillance médico-professionnelle de l’ exposition interne aux radionucléides en INB”( SFMT, 2011) establishes a benchmark value of 1.25 mBq / L, which corresponds to an activity between 1 and 3 mBq over 24 hours depending on daily diuresis( Recommendation 54). This value is also much higher than the
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