Officially, rainwater can no longer drink anywhere in the world. Although, far from what it may seem from some headlines or information, it is not that it has suffered an increase in its polluting values or, suddenly, a new agent has been detected. There is a certain ‘trap’.
A study carried out by researchers from the University of Stockholm (Sweden) and the ETH Zurich (Switzerland), published in the journal ‘Environmental Science & Technology’, is the origin of everything. The research, in general terms, concludes that, indeed, rainwater “would be considered unsafe everywhere”. The reason? A change of criteria.
Rainwater, for several decades, has contained a type of substance called PFAS: per- and polyfluoroalkyl substances -in general, that have large amounts of fluorine- that spread through the atmosphere. These are very harmful to health: they can cause cancer, infertility, learning disabilities, etc.
The “safe” value was set at 70 ppt (parts per trillion) since 2016. From that presence, the water was considered harmful.
In June of this year, 2022, the EPA (United States Environmental Protection Agency) regulators established a new criterion: from the previous 70 they lowered the safety level to 0,004 ppt in the case of PFOA and 0,02 ppt in that of PFOS. In other words, and as stated in the report, this means lowering the security level to “37.5 million times”.
“Under new US guidelines for PFOA in drinking water, rainwater would not be safe nowhere in the world. Although we don’t often drink rainwater in the industrial world, many people around the world expect it to be safe and supplied,” explains one of the researchers.
The report, and this is why it is established, tries to explain that a “global level” of this type of pollutant should be maintained. For example, in Spain a weekly PFOA consumption of 6 ng/Kg of body weight per week is established and in Europe the established standard for domestic water is 0.00065 µg/L. That is, 650 ppt.
“So now, due to the global spread of PFAs, environmental media everywhere will exceed environmental quality guidelines designed to protect human health and we will be able to do very little to reduce PFA pollution,” explains Professor Martin Scheringer. , one of the authors of the report. “In other words, it makes sense. define a specific planetary boundary for PFAS and, as we concluded in the paper, this limit has already been exceeded.”