S-metolachlor is an organochlorine herbicide used in particular to weed maize crops but also sunflowers, soya, beetroot, sorghum, millets and beans.
What are the risks for the environment?
S-metolachlor is moderately persistent (long half-life) and moderately mobile in soil.
It is soluble in water and has a low adsorption coefficient on soils, so it readily contaminates groundwater. In 2015, S-metolachlor was quantified in 35% of the analyses carried out in surface water.
What are the health risks?
S-metolachlor replaces metolachlor, a closely related molecule that has been banned in France since 2003 for its dangerousness and classified as an endocrine disruptor by the United States Geological Survey.
In October 2019, Syngenta (the manufacturer), warned of the importance of limiting its use in areas vulnerable to pollution, which proves that this approach to the substitution of active ingredients is not a sustainable response to the problem of pollution of aquatic environments by pesticides.
Analysis of S-metolachlor :
The degradation of S-metolachlor in the soil produces 2 types of metabolites (ESA metolachlor and OXA metolachlor), compounds that can be detected in dust samples, on a surface with a wipe, but also in the organism by analysis of hair or blood in case of acute exposure.
The main registered products including this molecule are:
- Mercantor Gold, Elina, Dual Gold Safeneur, Aliseo Gold Safeneur, Camix, Calibra from Syngenta
- Deluge 960 EC from Belchim
- S-Metolastar from Life Science LTD
- Amplitec C from Ascenza France