Chlorothalonil, a fungicide considered to be a “supposed” carcinogen, has been banned since 2020 in France. However, its proportion remains above the legal thresholds in one out of three drinking water samples.
Drinking water in France is largely contaminated by residues from a fungicide banned for several years, a sign of the persistence in the environment of traces of pesticides even long following the end of their use, according to a report from ANSES published on Thursday.
Present in one third of drinking water
The National Health Security Agency studied water samples throughout the country, including overseas territories, in particular looking for 157 pesticides and their metabolites, i.e. components resulting from their degradation. .
“Of the 157 compounds sought, 89 were quantified at least once in raw water and 77 in treated water”, indicates ANSES.
One case in particular caught the attention of the experts: the metabolite of chlorothalonil R471811 – the most frequently found, “in more than one out of two samples” – which led to the quality limit being exceeded (0.1 microgram/litre ) “in more than one in three levies”.
ANSES’s results are only partial and some territories are more affected than others. This would, for example, be the case for 90% of households in Loire-Atlantique. The investments needed to clean water run into the billions of euros and water stakeholders warn that consumers will have to pay for them in part.
A fungicide banned since 2020
This metabolite comes from the degradation in the environment of chlorothalonil, a fungicide that has been banned in France since 2020. The French authorities had been alerted to its frequent presence in Swiss drinking water. “These results show that, depending on their properties, certain pesticide metabolites can remain present in the environment for several years following the banning of the active substance from which they originated”, concludes ANSES.
The European Commission had not renewed the authorization for chlorothalonil in 2019marketed by the German Syngenta, and France had granted a grace period until May 2020 for the disposal of stocks of the product.
Brussels then underlined that it was “impossible to date to establish that the presence of metabolites of chlorothalonil in groundwater will not have harmful effects on human health”. The Commission quoted the conclusions of the European Food Safety Authority (EFSA), which considered that chlorothalonil “should be classified as a category 1B carcinogen”, that is to say a “suspected” carcinogen.
Kidney tumors in rodents
ANSES took up this argument in a note last year, recalling that studies on chlorothalonil had identified “kidney tumors in rats and mice”. The agency highlighted the “lack of data to prove that the metabolite chlorothalonil R471811 does not share the mode of action of the parent SA (active substance) leading to renal tumours”.
Contacted by AFP, the Professional Federation of Water Companies (FP2E), the Ministry of Ecological Transition and that of Agriculture had not reacted Thursday at the start of the followingnoon. These revelations come as the Minister of Agriculture, Marc Fesneau, wants to reconsider the procedure for banning another product, the agricultural herbicide S-metolachlor, not yet banned by the European Union.
ANSES announced on February 15 its desire to ban the main uses of this molecule, whose chemical derivatives have been detected beyond the authorized limits in groundwater.
“I will not be the minister who will abandon strategic decisions for our food sovereignty at the sole discretion of an agency”, then launched the Minister of Agriculture Marc Fesneau.