“50% to 75%” of tap water contaminated by pesticides in Deux-Sèvres “without risk to health”
The drinking water distributed at the taps of Deux-Sèvres is mostly contaminated by pesticide residues banned from use since 2020. Between 50% and 75% of drinking water sources” According to Elvier Aronica, director of the Deux-Sèvres delegation of the Nouvelle-Aquitaine Regional Health Agency (ARS), the department is concerned.
The pesticide residue in question is R471811, a sub-molecule of chlorothalonil that was considered a “probable carcinogen” in the past and therefore banned. But during research expeditions in 2023, ANSES found large amounts of this metabolite in its water analysis in France. His research into ARS health controls has therefore been streamlined since last summer.
“Exceeding does not endanger health”
At Deux-Sèvres, “We started searching for this metabolite R471811 in July 2023”. Result: “It is present in 50 to 75% of drinking water resources at varying levels but exceeds the threshold of 0.1 micrograms per liter”. This threshold of 0.1 micrograms per liter was set by health authorities “Quality Limit”. Cyril Cafiaux, Deputy Director of the ARS in Deux-Sèvres, says: “More than 0.1 micrograms per liter of water does not endanger the health of the consumer. There is no health hazard. »
Analyzes show that “With the exception of the two dams of Sebron and Touche-Poupard, the metabolite is present in both deep and surface water tables where we find traces only below the vigilance threshold of 0.1 micrograms per liter” . ARS representatives consider that “What is exceptional about the number of water tables affected by contamination, is the magnitude of this contamination and the relative effectiveness of those treatments.”
“Too hard to eradicate”
Though interconnected, the ten water unions of the department can hardly help each other by mixing their water as they are all more or less concerned. And the treatment is not very effective: “It is very difficult to remove metabolites in the treatment system. We get almost the same thing at the entrance and exit of the treatment plant”. And running out of possible treatments “Too expensive”.
According to representatives of the ARS in Deux-Sèvres, none of the analyzes showed a threshold higher than 3 micrograms per liter. The threshold at which water is officially considered no longer potable. Maximum? “About 2 micrograms per liter”, Cyril Kefiaks answers, without wanting to specify in which area of the department.
Expected release in April
as “Quality Limit Threshold” is exceeded, the water is forced to the unions “Submit Request for Exemption” To continue dispensing water to taps. “By the end of April 2024, water unions will submit these exemption requests which should include an action plan” To try to solve the problem. “Prefectural exemption order to be issued in early August 2024”, Announces the deputy director of the Deux-Sèvres delegation of the ARS who wishes to reassure: “In France, we have rules that are very protective. This is the principle of maximum precaution. We can grant this exemption because as long as we are below the value of 3 micrograms per liter, we can tolerate the consumption of this water during the exemption period. If there was a risk to subscribers’ health, we wouldn’t do it. »
What is the chlorothalonyl metabolite R471811?
> Chlorothalonil is a molecule present in insecticides, more precisely fungicides used in agriculture especially on cereal crops, vines or, for example, potato crops.
> This fungicide molecule has been banned since 2020 by the European Food Safety Authority after it was classified as a “substance considered to be potentially carcinogenic to humans”.
> When it degrades in the environment, it can be broken down into submolecules. Metabolite R471811 is one.
> The metabolite R471811 has been called for in water health checks conducted by regional health agencies from summer 2023 following a study by ANSES.
> This assay study showed that this pesticide metabolite was the most frequently detected, in more than one in two samples, the quality limit was exceeded in more than one in three samples.
> For the single metabolite R471811, two thresholds have been set by health authorities.
> The first is a “quality limit” set at 0.1 micrograms per liter. In addition, “the quality of the water delivered at the tap deteriorates”, suggests ANSES, which adds that “this does not in any way constitute a dangerous threshold for the health of consumers”.
> The second threshold is set at 3 micrograms per liter. When this “regulatory quality limit” is reached, the water is not considered potable.
