Metolachlor: what we know about this herbicide whose ban is debated

Metolachlor what we know about this herbicide whose ban is

There was an announcement and then a confirmation. Thursday, before the congress of the majority agricultural union, the FNSEA, Marc Fesneau announced that he asked the French Agency for Health Security (Anses) to reconsider its desire to ban the main uses of S-metolachlor. Despite strong protests from NGOs, environmental MPs and his own camp, the Minister of Agriculture has chosen to persist. Because Saturday April 1, in a forum published on its twitter account, he said to assume his choice in the name of “food sovereignty”. In his text, Marc Fesneau calls for “posing the debate correctly” and “changing the method to move forward”.

The NGO Générations Futures immediately denounced a “scandal in terms of the protection of public health and the environment”. Several opposition elected officials, socialists and environmentalists, have deplored an attack on the independence of ANSES. MEP Pascal Canfin (Renaissance), quoted by The world, pointed out that the science was “now very clear about this herbicide” and that the priority was “to work on alternatives for farmers, not to fight the battles of the past”.

A herbicide known to be present in water

S-metolachlor is a herbicide widely used by French farmers, particularly for corn, soybean and sunflower crops. “Its degradation in the soil produces several metabolites, such as ESA metolachlor, OXA metolachlor or even NOA metolachlor, which are very easily found in underground waterways and in water intended for consumption”, indicates Hélène Blanchoud. , teacher-researcher on water contamination by pesticides, and president of the French group for research on pesticides (GFP). “We observe that the substance of S-metolachlor has a high mobility,” she adds.

In order to maintain a certain quality of the water distributed at the tap, European regulations set, for these substances, limits of presence in the water that must not be exceeded. Concerning the active substances of pesticides, such as S-metolachlor and its so-called relevant metabolites (i.e. those which are considered to pose an unacceptable health risk for the consumer), the quality limit is set at 0.1 microgram per liter . But this road line is often exceeded. “During the spreading periods, generally between the months of April and June, we are able to observe around 30 micrograms per liter of a metabolite of this pesticide”, notes Hélène Blanchoud.

In 2021, according to official figures, quoted by our colleagues from World, nearly 3.5 million French people received tap water that did not meet the quality criteria set by the European Union. In question: the presence of a metabolite of this pesticide beyond the regulatory threshold. If the study of pesticide substances in water shows their increasing number since 2018, it is in particular because the health control of the quality of water intended for human consumption (ECDH) has largely evolved in recent years, in particular in terms of performance of analytical methods. The finding of an almost generalized presence of these substances in groundwater was also established in autumn 2021 by ANSES.

A health risk?

In his opinion given on February 14 last, the French Health Security Agency (Anses) justified its decision to ban the pesticide because the presence of its metabolites (OXA, NOA and ESA) in groundwater “exceeds the quality limit set by the legislation European in the matter”. “In order to preserve the quality of water resources, ANSES is initiating the procedure to withdraw the main uses of plant protection products based on S-metolachlor”, wrote the agency.

Factually, in this opinion, although ANSES indicates that groundwater is indeed polluted by the metabolites of S-metolachlor, it does not mention any major risk for the health of consumers. According to Hélène Blanchoud, “the decision to ban S-metolachlor comes from the fact that we do not have enough knowledge about the toxicology of all the metabolites of this molecule. In other words, it is the precautionary principle which applies”. And to add: “It is not because we find a substance in large quantities in the water that it is necessarily dangerous to health.” Nevertheless, the teacher-researcher admits that if the toxicity of S-metolachlor has not yet been the subject of a completed study, it is because of the slowness of research, partly linked to the underfunding of the sector. “We spend more time looking for funds than developing our research. So the studies are progressing as best they can…”

Summoned before the Economic Affairs Committee of the National Assembly on March 29, the Director General of ANSES, Benoît Vallet, recalled that the prohibition of the product was motivated by “the very marked ubiquitous presence, in all types water, S-metolachlor and its metabolites”. Additionally, in June 2022, S-metolachlor was classified as a “suspected carcinogen” by the European Chemicals Agency.

In the text published on his Twitter account, Minister Marc Fesneau ensures that the expertise or the role of ANSES “have never been called into question”. He justifies his position by “the necessary synchronization and consistency” with the European calendar, without commenting on the health risks associated with this herbicide. Indeed, the European Commission is supposed to decide in the coming months on whether or not to maintain the herbicide in the EU.

“If we ban a substance like S-metolachlor, farmers will want to ensure their agricultural yield and therefore perhaps use other substances, which are potentially more harmful than those we know”, underlines Hélène Blanchoud . “It’s very complex. Sometimes you have to have the frankness to say that you don’t know while waiting for more details,” she concludes.



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