La Rochelle disconnects water site after herbicide detection

Authorities in La Rochelle have disconnected the Fraise catchment site near Vérines from the drinking water network following the detection of two prohibited herbicide metabolites. The contamination was identified during routine checks in September 2026 after the Regional Health Agency (ARS) reported non-compliance.

Analyses revealed traces of flufénacet-ESA at 0.82 µg/L and metolachlor NOA at 1 µg/L. While the flufénacet concentration exceeds the quality threshold of 0.1 µg/L, it remains significantly below the potability limit of 8.8 µg/L. Local officials have stated there is no imminent health risk to the population.

As a precaution, the affected areas, including Bourgneuf-Montroy and parts of central La Rochelle, are being supplied by the Coulonge plant. The La Rochelle Agglomération has filed a legal complaint against unknown parties to determine the origin of the pollution and establish responsibility.