Eight town halls, including one in the Alpes-Maritimes region, are temporarily removing tuna from their school canteen menus to "stop children's exposure to mercury."

In October 2024, the NGOs Bloom and Foodwatch warned of mercury contamination in tuna after having 148 cans of canned tuna randomly tested by an independent laboratory.

The study showed that 100% of the boxes tested were contaminated with mercury, classified by the World Health Organization (WHO) as one of the ten substances of greatest concern to public health.

Criticizing the lack of measures taken since this study, the signatory cities, which also include Mouans-Sartoux (Alpes-Maritimes), Bègles (Gironde), Grenoble, Lille, Montpellier and Rennes , have decided "not to serve tuna-based products in school menus."

"Children, the first victims of this standard, established without taking into account consumer health, can very quickly exceed the tolerable weekly intake (TWI), i.e. the maximum quantity that can be ingested regularly over the course of a lifetime before being exposed to a health risk," warn the eight signatory communities in a press release.

"Once ingested, this powerful neurotoxin can lodge in the brain and have devastating effects, particularly on the neuronal development of young children (lower IQ, neuromotor disorders, behavioral disorders, memory disorders, etc.)," ​​the press release continues.

According to Bloom, more than one in two cans tested had mercury levels that exceeded the maximum limit set for other fish species such as cod or anchovies, which is 0.3 mg/kg.

For tuna, the limit has been set at 1 mg/kg, but this threshold is calculated on the "fresh product".

However, according to the NGO's calculations, this amounts to a content of approximately 2.7 mg/kg in the can, because the mercury is more concentrated once the product is dehydrated.

"What's quite surprising is that tuna is entitled to an exemption from mercury levels compared to other fish. We want to apply the precautionary principle," Gilles Pérole, deputy mayor of Mouans-Sartoux, explained to AFP.

The absence of tuna from menus "cannot be reviewed without the maximum limit of mercury authorized in tuna being lowered to the strictest level existing for fish, namely 0.3 mg/kg," the authorities specify.

"Companies comply with current regulations and no product placed on the market exceeds the regulatory threshold of 1 mg/kg," the Federation of Preserved Food Industries reacted in a press release, estimating that the protocol used by Bloom's study "does not appear to comply with current standards, which would explain such discrepancies."

The profession also explains that it published in January "all the results of the controls of the last eight years", which show "rates observed on average three times lower than the regulatory threshold".