Since 2019, Health Canada has set targets that govern the concentration of ten perfluorinated substances in drinking water. The lowest targets are 200 nanograms per liter (ng/L). New stricter standards, which are the subject of public consultation until April, target around thirty perfluorinated substances. The sum of their concentration should not exceed 30 ng/L, which is much less.

In the United States, the Environmental Protection Agency (EPA) set in mid-March at 4 ng / L the limit for two perfluorinated in drinking water.

Four other perfluorines are also targeted by the EPA, according to a complicated calculation with thresholds ranging from 9 to 2000 ng / L, according to Mr. Sauvé. EPA standards must be enforced by all states, which may even adopt more stringent standards.

Some states – for example, Michigan since 2020 – already monitor perfluorides in drinking water. “I think in Canada we should go to lower limits, like in the United States,” said Scott Hopkins, a chemist at the University of Waterloo, specialist in the measurement of perfluorides in drinking water and sewers. .

Sébastien Sauvé applied the new EPA standards to his analysis of perfluorides in drinking water in Quebec, published in mid-February in the journal Water Research. The number of municipalities exceeding the thresholds is five under the proposed Canadian standard of 30 ng/L, but rises to eight when applying the EPA standard. Thus, the American standard would tip Sainte-Pétronille, Longueuil and Waterloo into the camp of cities where drinking water contains too many perfluorinated substances, in which Val-d’Or, Saint-Donat, Sainte-Adèle, L’ Epiphany and Sainte-Cécile-de-Milton according to the standard envisaged in Canada. It should be noted, however, that these measurements are fluctuating: at L’Épiphanie, a subsequent measurement reported levels below the standard of 30 ng/L.

“The City is following this file closely through its participation in the Industrial Chair in Drinking Water at Polytechnique Montréal, in collaboration with other municipal partners,” said Louis-Pascal Cyr, spokesperson for the City of Longueuil.

With the proposed new standards, Canada “is, in my view, more stringent than the US approach, which only covers a few perfluorines,” says Sébastien Sauvé.

The Canadian federal standard is not mandatory, but some provinces, including Ontario and British Columbia, are more advanced in this area than Quebec – which does not limit the presence of perfluorides in drinking water.

Quebec’s Direction Nationale de Santé Publique is following the case, according to Public Relations Officer Robert Maranda of the Ministry of Health and Social Services, who points to “uncertainties regarding the likelihood and significance of health effects” from perfluorides. At the end of February, the national director of public health, Luc Boileau, told Radio-Canada that the water in Quebec’s distribution networks was “very drinkable”, despite the presence of perfluorides.

Discovered in the 1940s, perfluorines are very resistant, which is positive for the industry, but it allows them to accumulate in the environment and living organisms without being degraded. They are notably used in stain repellents, anti-adhesives and high performance fire-fighting foams. An increased risk of certain cancers has been observed in populations living near highly contaminated sites, and more recently, immune problems at more widespread rates, driving the new norms.

The half-life (a technical measure of the elimination of half of a quantity of a product) of perfluorines sometimes approaches ten years. “We call them eternal pollutants, but that’s a bit of a misnomer, we’re not talking about hundreds or thousands of years,” Sauvé says. Good news: concentrations in the American population of certain perfluorinated substances banned in 2004 by the Stockholm Convention on Persistent Organic Pollutants, which notably covers PCBs, have started to drop, according to the Centers for Disease Control (CDC) of the American government. . Theoretically, the regulations do not only include perfluorines, but also polyfluorines. The English acronym PFAS is also used to designate them, or in French “substances alkylées perfluorées ou polyfluorées”.

The few private laboratories capable of analyzing the amount of perfluorides in drinking water in Quebec probably have a detection limit of 4 ng/L, according to Mr. Sauvé. “With a little effort, they should be able to get down to 1 ng/L. That should be enough to meet the new Canadian standard. Sauvé’s lab has a detection limit of 0.05 to 0.1 ng/L, depending on the molecule, and covers 75 kinds of perfluorines.

At the University of Waterloo, Mr. Hopkins is working on a new technology for detecting perfluorides in wastewater. “Current techniques work with relatively clean waters,” says Hopkins. With sewage, it is more difficult. If we want to identify the sources of perfluorides to eliminate the problem at the source, we will need new technologies. »

Molecules used since the 1950s as anti-stain and anti-adhesive agents, in particular in Teflon, as well as in military and airport fire-fighting foams, perfluorines do not degrade and accumulate in the environment and the body. They have carcinogenic potential and interfere with the immune system. Three perfluorines are banned by the Stockholm Convention on Persistent Organic Pollutants, signed by 152 countries in 2001 and coming into force three years later. This international agreement concerns 30 substances that persist for a long time in the environment and the human body.