Concern over Mercury levels in canned tuna sold in France

Concerns have been raised over the levels of mercury in canned tuna products in France following a report by two consumer watchdog organisations.

Bloom and Foodwatch said they carried out tests in independent laboratories on 148 cans of tuna across multiple brand types – which came from France, Spain, Italy, Germany, and the UK - and all were found to have traces of mercury, some of them significantly.

Over 50% of the tins had mercury levels above the thresholds given for fresh fish such as sardines, and one in ten had mercury levels above the legal limits on fresh tuna.

Of the 148 cans, the highest concentration was found in French brand Petit Navire at 3.9 mg of mercury per kg of fish. 

This is 13 times higher than the maximum amount for fish such as sardines, and almost four times the maximum for fresh tuna.

Ingestion of mercury can lead to “serious neurodevelopmental disorders in children and impair brain function in adults”, claim the NGOs, saying mercury consumption should be strictly limited.

It is also particularly dangerous for pregnant women.

The use of mercury for other purposes is gradually being banned, including in dentistry, where from next January it will be banned in fillings. 

Is it dangerous to eat? 

All of the cans tested did not breach EU rules for mercury levels in tuna, which are focussed on fresh tuna.

However, the organisations say in their report that this does not mean they are safe to consume. 

Tuna has a naturally higher mercury level than other fish, due to its position in the food chain (its diet contributes to the increased levels). 

Additionally, limits on mercury levels in fresh tuna are significantly lower than the levels of mercury actually found in canned tuna. 

The French government’s food safety agency Anses says the consumption of fish should be limited to twice per week, and people should specifically limit how much tuna they eat.

“The maximum mercury levels in tuna currently in force in Europe were established on the basis of the level of contamination found in the tuna and not on the basis of the danger that mercury represents for human health, in order to ensure the sale of 95% of the tuna,” say the organisations.

“Tuna is the most widely consumed fish in Europe: it should be all the more strictly regulated,” they add. 

They are calling for the maximum mercury levels allowed for tuna to align with the 0.3mg per kg rule in force for other fish. 

In addition, they want EU countries to “immediately activate a safeguard clause to ban the marketing of tuna products containing more than 0.3 mg/kg of mercury on their territory,” and withdraw meals containing canned tuna from school canteens, hospitals, care homes, and maternity wards. 

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