What are PFAS and are they toxic to humans and the environment? : Coups

Scientists are intensifying their research on the possible health effects of a large group of common but poorly understood chemicals used in water-resistant clothing, stain-resistant furniture, nonstick cookware and many other consumer products.

Per and polyfluoroalkyl substances are generally referred to by their plural acronym, PFAS. PFASs are resistant to water, oil and heat, and their use has developed rapidly since their development by companies in the mid-twentieth century. Today, the non-stick qualities of PFAS make them useful in products as diverse as food packaging, umbrellas, tents, carpets and fire-fighting foams. The chemicals are also used in the manufacture of plastic and rubber and in the insulation of cables.

In short, they are all around us. And as a result, they found themselves in the ground and, especially in some areas, in our drinking water.

"We find that they contaminate many rivers, many lakes, and many sources of drinking water supply," said Linda Birnbaum, director of the National Institute of Health Sciences of Canada. Environment and the National Toxicology Program. "And we find them not only in the environment, but we find them in people."

"Essentially, everyone has these compounds in our blood," she says.

This is partly because PFAS do not break down easily – a quality that has earned them the nickname "chemicals forever". Some varieties have been found to remain in the human body for years to decades. Others accumulate in the soil or in the water, creating a continuous source of exposure.

Despite their omnipresence, scientists know relatively little about the health effects of most types of PFAS.

No legal security limit PFAS for the moment

"Despite their daily use, the body of science needed to fully understand and regulate these chemicals is not yet as robust as it should be," acknowledged the deputy administrator of the Office. Water of the Environmental Protection Agency, David Ross, at a congressional hearing on the PFAS in March.

This year, the EPA has indicated that it is considering setting a legal safety limit for some PFAS in drinking water, but has not yet taken action.

At the same time, public spending on chemical research has increased. The National Institutes of Health, the Environmental Protection Agency, Centers for Disease Control and Prevention, and multiple university systems have all increased funding for their studies on PFAS in recent years .

"We have more and more beneficiaries studying PFAS in their studies – both mechanistic studies and animal studies," as well as epidemiological studies that analyze large populations, says Birnbaum. But the work is progressing slowly.

"It's a very broad class of chemicals – probably 5,000 or more – and it looks like new products are being produced all the time," she says.

In most cases, US chemicals regulations do not require companies to prove they are safe before they start selling them. It is up to the EPA to determine if a substance is dangerously unacceptable and under what circumstances. Such analyzes usually begin only after public health concerns have been raised.

As a result, "we really do not know much about the vast majority of these chemicals," says Birnbaum.

Scientists supported by the National Institutes of Health take an approach of simultaneously analyzing hundreds of PFAS varieties. The goal is to identify subgroups of PFAS with similar characteristics so that scientists do not have to do a battery of toxicity tests on each chemical.

"We will never be able to test 5,000 or more PFAS," says Birnbaum.

Early studies suggest some health risks

Some of the most important research in PFAS epidemiology conducted in the United States was conducted by a panel in early 2005 as part of a class action lawsuit against the DuPont chemical company. The case alleged that thousands of people living in West Virginia and Ohio had been injured by industrial releases of a chemical called PFFO, the PFAS.

The panel – made up of three career epidemiologists who both sides of the trial agreed to have evaluated the scientific evidence – have discovered a "probable link" between long-term exposure to the chemical and certain medical conditions, such as kidney cancer and thyroid disease.

Additional studies on humans and rodents have revealed similar associations.

"I think we have more and more information that at least some members of this class can pose a problem," Birnbaum said.

These results raised a host of new questions, first about the mechanism: how do PFAS chemicals work in the body? It's one thing to see an association between exposure to a substance and an illness. It is much more difficult to determine a likely path between chemical exposure to the symptoms of the disease.

"We still do not know what specific molecular way they produce toxicity," says Jamie DeWitt, a toxicologist who studies PFAS at East Carolina University.

For example, DeWitt and others have published studies on humans and rodents that suggest that exposure to a PFAS chemical – the APFO – may inhibit the body's response to vaccines.

"I'm pretty sure that a type of immune cell called cell B is involved" in this removal, DeWitt says. "But I do not know why cell B does not produce enough antibodies.It's a signaling molecule that says:" Hey, cell B, makes antibodies? & & # 39; Is it something that does not go inside the B cell itself – is it the amount of energy of the B cell? These are the molecular mechanisms that we are still trying to understand. "

Knowing these mechanisms for PFOA could help scientists estimate the potential risks of other PFAS systems with a similar structure, she says. "Honestly, I think we're still at the beginning."

According to Dr. Birnbaum, at the current pace of research, it will take about two years to fully understand the toxicity of the entire PFAS group. But there will always be a lot of questions for scientists and regulators.

"Realizing that these chemicals have escaped into the environment, how are we going to fix those problems, how are we going to get rid of those chemicals?" she says.

"One question we all need to ask is: what is essential?" she says. "Do we really need it?" Are there places where we need this class of chemicals to be safe? But if that's the case, we'd like them to be used in closed systems so that they do not escape and end up contaminating the whole world. "

Asked to comment on the importance of PFAS systems, a spokesperson for FluoroCouncil, which is part of the leading professional group representing chemical companies in the United States, defended their widespread use in consumer products.

"PFAS is an essential enabling technology that plays a vital role in products ranging from life-saving applications in pacemakers and defibrillators, to the design of reduced-emission automobiles with improved car safety, to the manufacturing of semiconductors, solar panels and high-performance electronic components "A FluoroCouncil spokesperson wrote in a statement sent by email to NPR.

"The vast differences within the PFAS chemistry family are not immediately obvious to many people," the statement said. "Although some names have the same name, PFAS have characteristics, formulations, intended uses, and different environmental and health profiles."

Living in uncertainty

Although two years are not long in the world of basic scientific research, it can seem like an eternity to people who care about their health. In response to public concern, some states are already acting alone, both to regulate emissions and exposure to PFAS and to collect public health information in communities where water is known to be contaminated.

"For people living in areas where one of their sources of drinking water has [of PFAS] this was high enough to cause concern, there is a very high demand for information, "says Alissa Cordner, a sociologist at Whitman College and organizer of a national list of contamination by the PFAS.

"There is so much uncertainty about the scale and consequences of the contamination," she says, and this uncertainty makes people scared. "As for people who want to know" What is in my drinking water? "The tests are always prohibitively expensive."

And even when scientists or officials test water in a community, the lack of scientific evidence on PFAS and health, so far, prevents people from knowing how to respond. According to the CDC, most household water filters do not effectively remove chemicals.

"I think it's confusing because you have so many chemicals that we know so little, except that they belong to this large class," Birnbaum said. "I think it's confusing, but it's also frustrating, so we're trying to fix those issues right now." Regulators, scientists and citizens all agree that research results can not come soon enough.