On tap, bottled, filtered… what water to drink to stay healthy?

Even though she heard that the water from Parisian taps has a good reputation, Clémentine started buying bottles following two deliveries in 2022 and 2023. This stock takes up a little space in her small three-room apartment from Boulogne-Billancourt (Hauts-de-Seine), but he quickly established himself. The nursing staff met by this young mother immediately advised her to turn to bottled water suitable for filling the bottles of her two infants.

But a microscopic parameter sowed doubt in Clementine’s mind: nano plastic particles. These tiny fragments invisible to the naked eye which are present in quantity in plastic bottled water* raise suspicions about their possible effects on human health. “Because of plastic, I will be more likely to choose tap water for the oldest of my children,” now estimates this 37-year-old woman, who, like two thirds of French people, mainly drinks tap water. faucet.

* Study conducted by the American universities Columbia and Rutgers.

The advertising campaigns of bottled water manufacturers focused on its supposed benefits are weakened. Under the influence of Evian advertisements featuring healthy babies, Joël, Clémentine’s husband, had initially purchased bottles of this brand of mineral water from the Danone group before a midwife advised the couple towards spring water, less loaded with minerals and trace elements. “Natural mineral waters and spring waters do not undergo any chemical treatment,” assures the House of Natural Mineral Waters, keen to preserve the image of purity of bottled water. Revelations made by The echoes, on January 29, however, suggest the opposite. A third of brands do not respect this ban and illegally filter the precious liquid to mask its initial contamination. Should we stop drinking bottled water? “It is difficult to know which water is best for health, but when it comes to plastic, tap water is less polluted,” says Rachid Dris, researcher specializing in microplastics at Paris-Est Créteil University.

More in-depth analyzes

The match between faucet and bottle gets complicated when you take a bigger picture. Let’s take the last threat identified around water. It is called PFAS – pronounced “piface” – and constitutes a family of ultratoxic compounds that are found in many everyday products (packaging, firefighting foams, kitchen utensils, etc.). Various studies have shown that these eternal pollutants are present in tap water in abnormal doses, particularly in Auvergne-Rhône-Alpes. As no threshold is imposed on bottled water operators in this area, it is difficult to know the exact extent of this pollution. “However, there is no reason to think that only tap water would be affected by this problem,” believes Marc Laimer, consultant. Especially since certain sources are exploited by both the bottled water industry and a municipality. This is the case for the Campbon water table which supplies the agglomeration of Saint-Nazaire (Loire-Atlantique) and a bottling plant for the Cristaline brand.

The structure responsible for ensuring good water quality in France is called the Regional Health Agency (ARS). It verifies that the maximum health values ​​established by the National Agency for Food, Environmental and Occupational Health Safety (ANSES) are not exceeded and regularly tests new molecules. This expansion of controls to new pollutants has led to an increase in health alerts. For consumers, there is plenty to swim between two waters. “With all these expert debates, we don’t really know what to believe anymore,” Clémentine breathes, a little lost. This makes it seem like there is no silver bullet. » Even filter jugs have “questionable” effectiveness according to a 2017 Anses study. Their use can even be counterproductive if the water jug ​​is exposed to ambient air for more than 24 hours, which leads to a microbial contamination.

This feeling of dizziness is reinforced by the time required for researchers to establish scientific truths. The effect of plastic nanoparticles on human health is still largely unknown; research in this area has only recently been initiated. The only certainty: in the laboratory, these molecules participate in inflammatory processes in rodents, leading to intestinal permeability. Same problem on the PFAS side. Although these particles are suspected of causing kidney cancer and dyslipidemia (an abnormality in cholesterol levels), we will have to wait to know exactly their consequences on health.

A polluted environment

If the ARS notices that the authorized thresholds are exceeded, the sites close to comply, whether they are operated by an industrial company or a community. North of Poitiers (Vienne), two running water catchment areas supplying homes were disconnected from the network in 2023 after the discovery of chlorothalonil levels exceeding the set health threshold. This pesticide residue, also called a metabolite, is classified as “possibly carcinogenic” by the International Agency for Research on Cancer (IARC). But if tap water appears contaminated by this pollutant, bottled water is not spared. Researchers from the Swiss Federal Institute of Water Science and Technology thus found, in 2020, chlorothalonil residues in Evian bottles, although at a level “much lower than the regulatory threshold”, the brand reports. Following the uproar caused last week by the discovery of the misleading practices of plastic bottle manufacturers, Nestlé indicated that it would close two wells in the Vosges which supplied its Hépar brand and two others in the Gard used by Perrier.

It is all the more difficult to escape the pollution of our environment by chemical components as it is widespread. Traces of PFAS have even been found by researchers even in the icy wilderness of the Arctic on polar bears. From vegetables to clothing to makeup, toxic products are everywhere. “We mainly focus on tap water, because communication is public on this product,” says Jérôme Labanowski, research manager on environmental quality at the CNRS. But if you drink two liters of water a day, that exposure to pollutants isn’t that great compared to what you’re exposed to through the rest of your daily intake. » Vigilance, therefore!