The government considers that the discovery of a fungicide residue in drinking water does not present a health risk. But franceinfo has discovered at least one measure that contradicts the government’s position.
The widespread presence of fungicide residues in tap water does not “no health risk” but “more regular measures” of the product will be put in place. This is what the government assured on Friday April 7, the day after the revelations of the National Health Security Agency (Anses) on the significant presence in water of pesticides and their metabolites, that is to say say components resulting from their degradation.
>> Read also: what we know about pesticide residues in tap water in thousands of municipalities (and uncertainties about their toxicity)
One case in particular caught the attention of experts: the metabolite chlorothalonil R471811 – the most frequently found, “in more than one out of two samples” – which leads to the quality limit being exceeded, set at 0.1 micrograms per liter (µg/L), “in more than one out of three samples”. Chlorothalonil is a fungicide banned in France since 2020.
A measure beyond the health risk threshold
The detection campaign “showed maximum concentrations of 2µg/L”underlines the Ministry of Ecological Transition on Friday in a statement sent to the press, also shared by the Minister of Agriculture. “The transitory health value making it possible to prevent a health risk being 3µg/L, the water sampled and analyzed is thus non-compliant, but does not present a health risk”he insists.
However, at the beginning of March, a sample exceeding this health threshold of 3 µg/L was indeed observed. According to data from the ministry, in Cuhon (Vienne), located 20 km from Poitiers, the R471811 molecule was measured on March 8 at 3.4 µg/L. “The person in charge of water distribution was asked to immediately review the dilution rates of the various resources in order to return below the health limit of 3 µg/L”, notes the ministry’s website. Since then, two new samples have been taken and the rates are lower: R471811 was measured at 0.81 µg/L on March 17, but at 2.2 µg/L on March 28.
“Don’t cry wolf”
On the spot, the mayor of Cuhon assures franceinfo that the inhabitants continue to drink tap water, and that he did not have to put in place measures to restrict water consumption. “Don’t cry wolf”puts Philippe Garanger into perspective.
According to franceinfo calculations based on official data, R471811 has only been measured in France since the course of 2022, and in only a dozen departments. Of the approximately 700 samples analyzing this molecule, the quality threshold, set at 0.1µg/L, was exceeded 65 times. Contacted regarding the existence of other exceedances of the health threshold, ANSES did not respond to our requests.
Uncertainties about the toxicity of these molecules
“The long-term health effects of exposure to low doses of pesticides are difficult to assess”, notes the Ministry of Health on its website. For most of the molecules concerned, the health authorities explain that exceeding the quality threshold does not mean that drinking tap water is toxic. It is still declared “non-compliant with quality requirements”, and the manager is required to implement measures to stem the phenomenon. The water therefore continues to be distributed as long as it does not exceed a second threshold, called “maximum sanitary value”.
But for several molecules, including R471811, the authorities lack scientific data to set this maximum health value. In this case, they apply another threshold, called “transient health value”, and set at 3 μg/L. This new limit still does not provide, for the moment, the automatic prohibition of the consumption of tap water, but leads to reinforced monitoring.
Environmental NGOs reacted Thursday by calling for a change in the agricultural model, with less use of pesticides. This report comes as the Minister of Agriculture, Marc Fesneau, wants to slow down the procedure for banning another product, the agricultural herbicide S-metolachlor, not yet banned by the European Union. The ANSES report “invites the actors concerned to prepare as soon as possible for the end of the use of pesticides”underlines the Ministry of Ecological Transition.