The French National Agency for Food, Environmental and Occupational Health Safety (ANSES) proposes to ban the main uses of S-metolachlor herbicide. The substance and its breakdown products are highly toxic to water organisms. The herbicide is also a suspected carcinogen. Water and environmental organisations in France have asked for a ban for a long time. Now a new ANSES report shows that its concentrations in groundwater are expected to be above the quality limit set by European legislation. The proposed ban is welcomed, however it should have been much faster.
What is S-metolachlor?
S-metolachlor is a herbicide mainly used on field crops of maize, soya or sunflower. Authorised since 2005, it is the third most widely used herbicide in France after glyphosate and prosulfocarb. The metabolites of this substance that form in the soil strongly contaminate groundwater and drinking water. In 2021, 3.4 million French people drank non-compliant water due to the presence of ESA metolachlor, the main metabolite of S-metolachlor.
The EU authorisation expired on 31 March 2015. Ever since, the substance has been under re-evaluation (and authorisation prolonged) at European level, for 8 years now! In this context, new toxicological and epidemiological studies have been analysed. These new data have led the European Chemicals Agency (ECHA) to classify S-metolachlor as a suspected carcinogen in June 2022.
In 2021, ANSES, the National Agency for Food, Environmental and Occupational Health Safety, collected data on the toxicity of S-metolachlor and already concluded that: “In light of this risk to the quality of water resources, ANSES is initiating a procedure to withdraw authorisation of the main uses of plant protection products containing the active substance S-metolachlor. This will reduce environmental contamination by this substance and thus help gradually restore the quality of groundwater.”
It appeared however that data was available much earlier leading to the chemical classification as a suspected carcinogen. EU-wise, it was only classified as such in 2022 by ECHA.
When the active substance is classified as a suspected carcinogen, the industry must provide evidence that its metabolites are not carcinogenic themselves. As no data on metabolites were provided by manufacturer Syngenta, the metabolites are therefore considered by the Anses to be relevant as a precautionary measure, as evidence for their non-classification is lacking. However, for a product use to be authorised, relevant metabolites must have predictable concentrations in groundwater
Evaluation process too slow
How come it took 8 years since the expiration of the authorisation to finally ban this substance? The regulations have been criticised to be far too slow when it comes to toxic substances such as S-metolachlor.
“This slowness of the European evaluation process is responsible for so many years of contamination of groundwater and drinking water by metabolites," stated François Veillerette, spokesperson for Générations Futures.
The same took place in Denmark with the fungicide Cyazofamid, which only was proposed to be withdrawn after 20 years of heavy usage. "We have to recognise that the approval system is not safe and that we don't know enough about the pesticides that are approved today. It is simply not good enough," said Maria Reumert Gjerding.
Nonetheless, the ban of S-metolachlor remains a victory for Générations Futures because they asked the ANSES, following the European regulations and methodologies, to withdraw all S-metolachlor-based products since September 2022. Today, even if the withdrawal is not total, it will affect many uses.