Humans fill the world with trash, but not all of our trash is visible to the naked eye.
While plastic trash on the beach is easy to spot, microplastics and “forever chemicals” have leached everywhere without us barely noticing.
These two forms of pollution are now so pervasive in the environment that they come down with the rain. But while the potential threat of microplastics is a regular talking point, some researchers say the spread of other persistent synthetic compounds is relatively overlooked.
A team of scientists in Europe are now worried that we have crossed a critical line. They argue that the presence of chemicals forever in our hydrosphere at values that exceed key guidelines means that we have entered a dangerous operating space from which there is virtually no return.
The warning follows another warning document, which argues that the world has exceeded the planetary safe limit for synthetic chemicals.
As with microplastics, the potential health effects of durable per- and polyfluoroalkyl substances (PFAS) are still largely unknown.
While some types of PFAS are linked to potentially dangerous effects, such as cancer, rigorous research lags behind and government safety thresholds in the United States are largely not enforced.
Researchers in Europe fear that if certain forever chemicals turn out to have toxic effects in the future, it will be too late.
A worldwide analysis of PFAS levels over the past ten years found that PFAS levels in rainwater “often greatly exceed” US Environmental Protection Agency (EPA) advisory levels. They also often exceed Denmark’s guidelines (which, after the United States, are the strictest, globally).
Contamination is constant even in remote areas like the Tibetan Plateau, where researchers have found that some chemicals exceed EPA guidelines by 14 times.
“Based on the latest US guidelines for PFOA in drinking water, rainwater anywhere in the world would be deemed unsafe to drink,” says environmental chemist Ian Cousins from Stockholm University in Sweden.
“Although in the industrial world we do not often drink rainwater, many people around the world expect it to be safe to drink and to supply many of our drinking water sources. “
In Sweden, for example, a nationwide mapping of PFAS found that nearly half of municipal drinking water exceeded safe levels.
It’s not just the water that’s affected. PFAS also seep into soils, and this soil contamination regularly exceeds guideline values in Europe.
In fact, industry players in the Netherlands have had such difficulty meeting past safety standards that the Dutch government has simply relaxed its guidelines.
Meanwhile, in the United States, guidelines on PFAS are becoming stricter as scientists learn more about the effects of these chemicals on human health.
This year alone, the US EPA recently lowered its safety threshold for certain types of PFAS because they were found to be more dangerous than regulators thought.
In 2020, the Environmental Working Group, a government watchdog, warned that there were dangerous levels of PFAS in many drinking waters in the United States. This group, however, has a history of exaggerating the health effects of certain chemicals and, at the time, EWG’s safety levels for PFAS in drinking water were well below the guidelines of the EPA.
Not anymore. In 2020, the EPA’s health advisory for two classes of chemicals, called 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 new, barely detectable levels, about half of the US population would be exposed to potentially harmful chemicals, according to EWG research.
“There has been an astonishing decline in guideline values for PFAS in drinking water over the past 20 years,” Cousins says.
“The drinking water guideline value for a well-known PFAS substance that is possibly carcinogenic has apparently declined 37.5 million fold in the United States.”
It is not a good sign. This suggests that regulators have overlooked or underestimated the risks associated with certain types of long-lived, military-produced, manufactured chemicals contained in products like Teflon, Scotchguard and foam.
“Regardless of whether one agrees or disagrees with our conclusion that the planetary limit for PFAS has been exceeded, it is nevertheless highly problematic that wherever on Earth humans reside, the recently proposed health advisories cannot be achieved without significant investment in advanced cleaning technology,” the authors. conclude.
“Indeed, although PFOS and PFOA were phased out by one of the major manufacturers (3M) 20 years ago, it will be decades before land water and precipitation levels approach low levels of picograms per litre.”
The recent analysis only considered four types of PFAS, meaning these results are likely just the tip of the iceberg. Hundreds of other persistent chemicals are also leaching into the environment at the same time, and most of their risks are unknown.
Federal regulations simply do not keep up with the scale of the problem.
The study was published in Environmental science and technology.