“Who pollutes our tap water? », Haro on the water

Critique More and more pollutants are present in drinking water… How is this possible and why? Hugo Clément leads the investigation in this new episode of “On the front”. Tonight at 9:05 p.m. on France 5.

It is part of our daily lives, seems almost banal to us, and yet water, to become drinkable, requires significant treatment and must meet specific criteria. It remains to be seen by what standards we define water suitable for consumption. This is what this new episode of “On the Front” effectively explores, where Hugo Clément takes us to the four corners of France to observe the massive presence of pollutants in our tap water: nitrates, pesticides, Pfas – substances in the name evocative of “eternal pollutants”…

Sleight of hand

He reveals to us a surprising method for treating overly polluted water: we mix it with cleaner water to dilute it below the limit thresholds. But who determines these thresholds? The case of chlorothalonil, a carcinogenic pesticide banned from spreading in France since 2010, is exemplary: a third of the collection points tested in 2022 were found to be above the limit of 0.1 microgram per liter. What to do? The public authorities have simply raised the standard to 0.9 micrograms, bringing almost all collection points to acceptable thresholds. This decision was taken on the basis of a study according to which the residues of this pesticide were not carcinogenic, a study carried out by Syngenta, the company manufacturing chlorothalonil! Our Swiss neighbors, who are more cautious, have maintained the standard of 0.1 micrograms: we therefore drink water that is prohibited in their country. The presentation of this French sleight of hand is one of the strong points of the magazine, which also evokes the etiquette games of mineral water sellers.

Another subject covered in this investigation: the sources of this pollution. Agriculture and industry are of course responsible, as are, more surprisingly, the vestiges of history. The war of 14-18, for example, continues to spread its poisons into the soil and then into our waters. As the main theme of the investigation, we follow the fight of Mickaël Derangeon, a professor of neuroscience, deputy mayor of Saint-Mars-de-Coutais, near Nantes. At the head of the local water union, he works to involve farmers: eliminating pollution upstream rather than treating it at great expense downstream, a logical idea, but still rare in France.

◗ Monday November 25 at 9:05 p.m. on France 5. On the front, presented by Hugo Clément. Directed by Thomas Raguet (2024). 1h00. (Available in replay on france.tv).