Radioactive tritium in tap water: more than 2,300 municipalities affected, including around twenty in Gard and Lozère

Le record de tritium retrouvé dans l’eau est à Châtellerault et Naintré, dans la Vienne.

Analyses carried out between 2016 and 2024 in France have revealed the presence of tritium in the drinking water of several thousand municipalities, reports Médiapart.

A survey Médiapart published on December 9th provides an update on the quality of drinking water in France. And the results are far from reassuring.

More than 2,300 municipalities concerned

An analysis carried out by our colleaguesand the Independent Research and Information Commission on Radioactivity (CRIIRAD) based on data from regional health agencies (ARS), reveals the presence of tritium, a radioactive element, in the tap water of more than 2,300 French municipalities between 2016 and 2024

Tritium is a radionuclide (radioactive atom) derived from hydrogen that is released by nuclear facilities. It emits very low-energy beta radiation. These are easy to block when they are outside a body, by metal or glass for example. But inside, “nothing prevents it from irradiating”, explains Médiapart.

Taking into account all the French municipalities where tritium has been detected at least once since 2016 above the background level of 2 Bq/l, a quarter of French people are affected, with 16.3 million people.

How to explain it?

According to Julien Syren, co-director of Criirad, the most affected municipalities are those “that are on the rivers along which there are nuclear power plants: the Seine, the Loire, the Vienne, the Garonne and the Rhône”.

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The record for tritium found in water is in Châtellerault and Naintré, in the Vienne, downstream from the Civaux power plant. In March 2017, 65 becquerels per liter (Bq/l) of tritium were measured in the water. The “Bq/l” corresponds to the unit of measurement of “volumic activity” of a substance (its number of nuclei).

However, the presence of this radioactive derivative is difficult to determine because it is sometimes detected several dozen kilometers from a power plant, emphasize our colleagues at Médiapart.

In Occitanie, for example, the town of Comps in the Gard is located nearly 76 km from the Tricastin nuclear power plant in the Drôme but close to a watercourse (the Rhône). On August 28, 11 Bq/l were detected in the drinking water. Inland, the towns of Calvisson, Congénies and Caveirac are even more affected by tritium.

Is it dangerous?

For the French authorities, the presence of tritium in water is considered almost risk-free: “If we use the official assessment models, the risk is very low for the health of these people”, explains Bruno Chareyron, scientific advisor to Criirad.

However, scientists explain that there “are many uncertaintieson the effects of very low doses, particularly for tritium” on the human body.

Recent expert studies, however, have demonstrated the opposite. After analyzing 250 scientific publications on the subject, researchers Timothy Mousseau and Sarah A. Todd, from the University of South Carolina (United States), conclude that internal exposure to tritium “can have biological consequences, by damaging DNA, causing physiological and developmental damage, reducing fertility and longevity, and increasing the risk of diseases, including cancers”.

The municipalities concerned in Occitanie

The list of municipalities in Gard where more than 10 Bq/l of tritium in the water have been measured:

– Nîmes

– Caveirac 

– Clarensac

– Saint-Côme-et-Maruéjols

– Saint-Dionisy

– Langlade

– Milhaud

– Bernis

– Nages-et-Solorgues

– Calvisson

– Congénies 

– Rodhillan

– Comps

– Beauvoisin

– Le Grau-du-roi 

The list of municipalities in Lozère where more than 10 Bq/l of tritium in the water have been measured:

– Monts-de-Randon

– Les Monts-Verts

– Terms

– Grandvals