People fill the world with garbage, but not all waste is visible to the naked eye. While plastic litter on the beach is easy to spot, microplastics and substances called “eternal chemicals” have traveled impressive distances without us noticing.
Both forms of pollution are now so ubiquitous in the environment because they fall at the same time as rain. But while the potential threat of microplastics is a common topic of discussion, some researchers argue that the spread of other persistent synthetic compounds is relatively overlooked.
A team of scientists in Europe is now worried that we have crossed a critical line. They argue that the presence of “eternal chemicals” in our hydrosphere, at levels exceeding permissible limits, means that we have entered an unsafe operating space from which there is virtually no return.
The warning follows another paper, which claims the world has breached the safe planetary limit for synthetic chemicals. Similar to microplastics, the potential health effects of long-lived per- and polyfluoroalkyl substances (PFAS) are still unknown.
Potential risks for the near future
While some types of PFAS are linked to potentially dangerous effects, such as cancer, rigorous research is lagging, and government safety thresholds in the United States are largely unenforced. Researchers in Europe are worried that if some ‘eternal chemicals’ prove to have toxic effects in the future, it will be too late, indicates Science Alert.
A global review of PFAS levels over the past ten years found that levels in rainwater “often far exceed” what the US Environmental Protection Agency (EPA) recommends. Contamination is constant even in remote areas like the Tibetan Plateau, where researchers have found some chemicals exceed EPA guidelines by 14 times. “Based on the latest US guidelines for PFOA in drinking water, rainwater everywhere would be considered unsafe to drink,” says environmental chemist Ian Cousins of Stockholm University in Sweden.
“Although we don’t often drink rainwater in the industrialized world, many people around the world expect it to be safe to drink and it supplies many of our drinking water sources.” In Sweden for example, a national PFAS mapping showed that almost half of the municipal drinking water exceeded the safe level. Meanwhile, in the US, PFAS guidelines are getting stricter as scientists learn more about what these chemicals do to human health. Just this year, the US EPA recently lowered its safety threshold for some types of PFAS because they were found to be more dangerous than regulators thought.
The situation is becoming increasingly worrying
In 2020, the Environmental Working Group, a government watchdog, warned that there are unsafe levels of PFAS in US drinking water. However, the group has a history of exaggerating the health impacts of certain chemicals, and at the time, the EWG’s safety levels for PFAS in drinking water were much lower than the EPA’s guidelines.
In 2020, the EPA’s health advisory for two classes of chemicals, known as PFOA and PFOS, was 70 parts per trillion. Now, it’s much, much lower, specifically 0.004 parts per trillion for PFOA and 0.02 parts per trillion for PFOS. At these barely detectable levels, about half of the U.S. population would be exposed to potentially harmful chemicals, based on EWG research.
“There has been an astonishing decline in benchmark values for PFAS in drinking water over the last 20 years,” says Cousins. It’s not a good sign. It suggests that regulators have overlooked or underestimated the risks associated with some types of chemicals manufactured by the military and contained in products such as Teflon and foam.
There is an urgent need to adopt effective measures
“Whether or not one agrees with the conclusion that the planetary boundary for PFAS has been exceeded, it is still very problematic that everywhere on Earth, where people live, the recently proposed health recommendations cannot be achieved without major investments in advanced technology cleaning”, conclude the authors of the study.
“Indeed, although PFOS and PFOA were phased out by one of the largest manufacturers (3M) 20 years ago, it will take decades for land water levels and precipitation to approach the low allowable levels” .
The recent analysis only considered four types of PFAS, meaning these results are likely the tip of the iceberg. Hundreds of other persistent chemicals are also leaking into the environment at the same time, and most of their risks are unknown. Federal regulations are simply not keeping up with the scale of the problem.