11 percent of Switzerland’s population exposed to water contaminated with Chlorothalonil

Levels of the chemical Chlorothalonil exceeding 0.1 micrograms per litre have been detected in the water used by around 700,000 people in Switzerland, reported RTS.

Chlorothalonil is a chemical found in fungicides used to protect crops, preserve wood and to give paints antifungal properties. Typically among the top three most used agrochemicals it is used heavily in the production of peanuts, potatoes and tomatoes. It is also used on lawns.

Use of the chemical was banned in Switzerland on 1 January 2020. However, it is a highly persistent chemical that enters soil and waterways and lingers.

Recently published data collected between 2019 and 2021 show that around 700,000 people in Switzerland are exposed every year to water containing more than 0.1 micrograms per litre. 700,000 represents around 11% of the population in the 18 cantons that have sent data to the federal government. Exposure rates to the chemical in Switzerland’s 8 other cantons were not included.

The population on Switzerland’s plateau, where most intensive farming is, is the worst affected, in particular people in the cantons of Aargau (24% of the population), Schaffhausen (47%) and Solothurn (50%).

In French-speaking Switzerland, Fribourg (17%), Vaud (14%) and Bern (10%) had the highest levels of exposure. In Geneva, Neuchâtel and Valais none of the population was shown to be exposed to Chlorothalonil above the level of 0.1 micrograms per litre.

The cantons of Basel-City, Basel-Landschaft, Zurich, Zug, Schwytz, Obwalden, Nidwalden, St. Gallen did not report water Chlorothalonil levels.

Chlorothalonil is classified as a Group 2B “possible human carcinogen” by the International Agency for Research on Cancer (IARC), a division of the World Health Organisation (WHO). Chlorothalonil has been connected with cancers and tumors of the kidneys and forestomachs in laboratory animals fed diets containing Chlorothalonil. The IARC has a long list of possible human carcinogens, which include the human papillomavirus, lead, melamine (a type of hard plastic) and traditional asian pickled vegetables.

Following the ban in 2020, chemical company Syngenta challenged the ruling at Switzerland’s Federal Administrative Court (FAC). After two and a half years the FAC has not yet reached a decision.

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