Where exactly is the line between harmless and harmful? The contamination of the world by PFAS (per- and polyfluoroalkyl substances), a family of thousands, if not millions, of ultra-toxic compounds that do not degrade in the environment, raises pressing public health questions. Is there even a “safe” value?
For more than ten years, Philippe Grandjean (University of Southern Denmark and Harvard T.H. Chan School of Public Health, USA) has been saying that our drinking water should not contain more than a single nanogram per liter of these “pollutants”. eternal”. Already in 2012, the work of this renowned environmental health professor had shown a negative effect of PFAS on the immune response of children to vaccines. “For every doubling of PFAS exposure, children had, on average, 50% lower antibody levels,” he explains.
In other words, according to our calculations: a quarter of a drop of perfluorooctanoic acid (PFOA), which was used to manufacture Teflon, in an Olympic swimming pool would already be too much. A dose to which more than 200 million Americans, or nearly two-thirds of the population, are exposed every day by drinking tap water.
It was on the basis of this research that in June 2022 the United States Environmental Protection Agency established indicative health limit values ??so tiny that the detection tools used today are not able to detect them. identify, such as 0.004 ng/L for PFOA.
Revision of thresholds
All of the PFAS experts we interviewed are adamant that the limit values ??set by the European Union are far too high. In 2020, the EU Water Framework Directive set them at 100 ng/l for the sum of 20 PFAS “considered of concern” and 500 ng/l for the total sum of all PFAS. All for an entry into force which will not take place before… 2026.
“These limits were visionary at the time they were discussed [in 2017-2018],” comments Gretta Goldenman, an environmental lawyer and expert on PFAS, “but we’ve learned so much about PFAS since then. and their effects on health that they now seem obsolete. For her, unlike a guarantee of safety, a concentration of 100 ng/l constitutes the threshold which qualifies a site as a “hotspot”, a hot spot of pollution. “The limits will have to be revised at some point depending on the criteria for immunotoxicity or not,” said Ian Cousins, professor of environmental chemistry at Stockholm University. And, if so, they will have to be reduced. »
For its part, the European Food Safety Authority has advanced a very low tolerable weekly intake in 2020, which would correspond to 4.4 ng/l. An untenable dissonance in a country such as Denmark, which has adopted its own limit values, the lowest on the continent, with 2 ng/l for the sum of all the PFAS detected in a single sample.
Our survey shows that over 17,000 sites across Europe exceed 10 ng/l and over 2,100 hotspots are above 100 ng/l.
