Mark Wilson / Getty Images
Scientists are raising research on possible health effects of a large group of commonly but less-understood chemicals used in water-resistant clothing, stain resistant appliances, nonstick cookware and many other consumer products.
The polyfluoroalkyl substance is commonly referred to by their plural acronym, PFAS. PFAS is resistant to water, oil and heat, and their use has expanded rapidly since they were developed by companies in the mid-20th century. Today, PFAS's nonstick qualities provide them with useful products that differ as food wraps, umbrellas, tents, carpets and fire foam. Chemicals are also used in the manufacture of plastic and rubber and insulation for wiring.
In other words, they are all around us. And because of this, they found their way to the ground and, especially in some regions, in our drinking water.
"We see them being exposed to many rivers, lakes, lots of drinking water," says Linda Birnbaum, director of the National Institute of Environmental Health Sciences and the National Toxicology Program. "And we not only find them in the environment, but we discover them to people."
"Everyone has these compounds in our blood," she explains.
This is part because PFAS don & # 39; easy to break – a quality that got them nicknamed "chemicals forever." Some varieties are found to be placed around in the human body for years, if not decades. Others gather in the ground or in water, creating a steady source of exposure.
However, despite their peculiarities, scientists know little about the health effects of most PFAS types. "
" Despite their daily use, the body of science needed to fully understand and correct these chemicals is not as needed, "the assistant administrator of the Environmental Office of Water's Protection Agency, David Ross, at a PFAS congressional hearing in March.
This year, the EPA has stated that it is considering setting a legal safety limit for some PFAS in drinking water, but it has not yet taken action. , public expenditure on chemical research is subjected. The National Institutes of Health, the Environmental Protection Agency, the Centers for Disease Control and Prevention and many state university systems have increased their funding for PFAS education over the years.
Bastiaan Slabbers / NurPhoto by Getty Images
"We have more of our grantees looking at PFAS in their studies – both mechanical study and animal studies," as well as epidemiological studies to study large populations, explains Birnbaum. But the job is slowly occurring.
"These are a wide variety of chemicals – maybe 5,000 or more – and this is something like this all the time," he said.
In most cases, US chemical regulations do not require companies to prove that a chemical is safe before they start selling it. It is up to the EPA to find out if a substance is unacceptable and under what circumstances, and usually such a diagnosis will begin only after public health concerns can be raised.
As a result, "we do not know much about the great majority of these chemicals," says Birnbaum.
An approach assisted by scientists supported by the National Institutes of Health is to study hundreds of PFAS types simultaneously. The purpose is to identify PFAS subgroups with similar characteristics, so scientists do not need to take battery toxicity tests on each individual chemical.
"There is no way we can certify 5,000 or more PFAS," Birnbaum says.
Early studies indicate health hazards
Some of the largest US epidemiology studies of PFAS are conducted by a science panel since 2005 as part of a class action against the DuPont chemical company. The case is suspected that thousands of people in West Virginia and Ohio have been hurt by PFAS chemicals release chemicals called PFOA.
The panel – composed of three career epidemiologists that both sides of the court case sustained scientific evidence – seeing a "possible link" between long-term chemical exposure and some medical conditions, such as kidney cancer and thyroid disease.
Further studies of both people and rodents see similar associations.
"I think information grows that some of these class members can be a problem," says Birnbaum.
Findings that raise a lot of new questions, first about the mechanism: How does PFAS chemicals work in the body ? It is something to see a relationship between exposure to a substance and disease. It is more difficult to determine the likely path from chemical exposure to the symptoms of the disease.
"We still do not know the exact molecular way they make toxicity," explains Jamie DeWitt, a toxicologist who studies PFAS in East For example, DeWitt and others publish the studies of both humans and rodents indicating exposure to a chemical of PFAS – PFOA – can suppress the body's response to vaccines.
"I am sure that a type of immune cell called a B cell is involved" in that detention, says DeWitt. "But I do not know why B cells do not provide enough antibody. Does it say the molecules that say, & # 39; Hey, B cells, produce antibody? & # 39; Is something wrong with within the B cell itself? Is it the amount of energy that cell B is these are the molecular mechanisms we are still trying to figure out. "
Knowing the mechanisms for PFOA can help Scientists estimate the potential risks of other PFASs with similar structures, he says. "Actually, I think we are in the beginning."
At current research rates, Birnbaum says, it takes two years to get the main toxicity of the entire PFAS team. But there are still many questions for both scientists and regulators.
"Realizing that these chemicals are getting into the environment, how can we try these problems? How do we get rid of these chemicals?" he says.
"One question we all need is asking: What is important?" he says. "Do we really need it? Are there areas where we need to have this safe type of chemicals? But if so, we want to use them in closed systems so that they can not escape and infect the whole"
Asked to comment on how important PFAS, a FluoroCouncil spokesperson, is part of a major trade group representing US chemical companies, defending their widespread use of consumer products.
"PFAS is a vital enabling technology that has an important role in products from life-saving applications to pacemakers and defibrillators, to design lower-emission vehicles with enhanced vehicle safety, in manufacturing semiconductors, solar panels and high-performance electronics, "a FluoroCouncil spokesperson said in an email statement in NPR.
"The vast difference within the PFAS family of chemistry is not immediately obvious to many people," continued the statement. "While some of the names sound the same, PFAS has different features, formulations, intended uses, and environmental and health profiles."
Life with uncertainty
While the two years are not too long in the world of basic scientific research, it can be as infinite in people who are worried about their health. In response to public concern, some states are taking action on their own, both to regulate PFAS emissions and exposure and to gather public health information in communities where water is known to be contaminated.
"For people who live in areas where one of their sources of drinking water has a level [of PFAS] high enough to raise concern, there is a strong need for information," said by Alissa Cordner, a sociologist at Whitman College and one of the organizers of a nationwide PFAS contamination list.
"There is so much uncertainty around what size and the consequences of contamination," she explains, and uncertainty is frightening to people. "In terms of individuals who want to know" What in my drinking water? "The test will still be prevented."
And even when scientists or officials have tried water in a community, the lack of scientific evidence has been gathered, today, about PFAS and health makes it difficult for people to know how to respond. Most in-home water filters are not effective in chemicals, according to the CDC.
"I think it's confusing, because there are many chemicals about what we know to be small, except for its large members," says Birnbaum. "I think it's confusing, but it's too frustrating. So we try to deal with those problems now." All regulators, scientists and citizens agree: The results of the research can not arrive soon.