Herbicide S-metolachlor to be withdrawn in France to protect groundwater

French health and safety agency ANSES on Wednesday ordered a halt to some uses of one of the most widely used weedkillers in France, S-metolachlor, which is produced by Swiss chemicals company Syngenta, after finding excessive levels in groundwater.

Residue of S-metolachlor, used mainly on maize (corn), sunflower, soy and beet crops, were frequently detected at concentrations exceeding quality limits set by European legislation, ANSES said.

The agency noted in its opinion that it had taken into account the classification of "suspected of causing cancer" for S-metolachlor issued by the European Chemical Agency's Risk Assessment Committee (RAC) in June 2022.

"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," it said in a statement.

"This will reduce environmental contamination by this substance and thus help gradually restore the quality of groundwater," it added.

ANSES did not specify which were the "main uses" that would be banned. It had already reduced maximum use rates for maize, sunflower, soybean and sorghum crops in 2021.

Syngenta France said it took note of the decision but was surprised by the move, stressing there was no proven health risk linked to products containing S-metolachlor.

"A link to cancer is only suspected, not confirmed," a spokesperson for the company told Reuters.

Farm office FranceAgriMer said it was too early to estimate the potential impact of the decision on crop production.

Alternatives to some crop treatments can sometimes be found, but not necessarily this time, Benoit Pietrement, head of FranceAgriMer's crop committee, told reporters.

S-metolachlor is currently being examined at the European level as its approval needs to be renewed this year. Conclusions of the European Food Safety Authority (EFSA) are expected early this year.

Anti-pesticide group Generations Futures welcomed ANSES' decision despite the withdrawal not being total, saying it anticipated a likely European ban on the substance.