Reacción a "Reactions: Study warns of PFAS contamination in global water systems"

Per- and polyfluoroalkyl substances (PFAS) are chemical compounds that due to some of their properties (they are highly resistant, thermodynamically stable and non-flammable) are used in a large number of industrial and commercial products (non-stick cookware, food packaging and waterproof fabrics). According to the most recent research, more than 200 use categories and subcategories have been identified for more than 14,000 PFAS compounds. Due to these same properties PFASs are considered to be extremely persistent in the environment ("everlasting chemicals"), highly toxic and with the potential to bioaccumulate and biomagnify up the food chain, have been detected in wildlife, and represent a clear potential hazard to human health. In general, these compounds may act as endocrine disruptors and may have many other toxic effects, such as hepatotoxicity, immunotoxicity, reproductive toxicity and tumourigenic effects, among others. All these reasons have led to the use and production of some PFASs being banned in the Stockholm Convention on Persistent Organic Pollutants, and many (generally developed) countries have introduced regulations restricting the levels of PFASs in drinking water.

However, a paper published in the prestigious journal Nature Geoscience by Australian and US researchers (University of New South Wales and University of Oklahoma, respectively) has concluded that the true distribution and extent of PFAS contamination in global water resources is still unknown, and that a large fraction of global water resources may be contaminated by these compounds at levels that may exceed laws and regulations in many countries.

The researchers analysed PFAS data from more than 45,000 samples collected worldwide since 2004 to determine whether PFAS contamination in surface and groundwater exceeds national regulations. According to its results, a large fraction of the water sampled exceeds drinking water limits, and these exceedances depend on the jurisdiction and sources of the PFASs. Thus, in samples without a known source of PFASs, 31% of groundwater samples exceeded the limits proposed by the US Environmental Protection Agency, while in Canada and the European Union, values of 69% and 6%, respectively, were reached. Moreover, these exceedances tend to increase when samples with known sources of contamination (such as industries involved in PFAS production) are considered.

The authors conclude that many of the current studies may be underestimating PFAS contamination in the environment, as a limited number of PFASs (usually the same families) are usually monitored, and the actual contamination in global water resources may be higher than previously thought. They cite for example the case of fluorotelomer alcohols (FTOH) which are not directly measured in almost any study, but which may represent up to 8 % of the mass of PFAS entering a sewage treatment plant, e.g. from household textile washing.