By Aria Bendix —
NBC News
Perfluoroalkyls (PFAS), a class of synthetic chemicals used in the manufacture of consumer products, can remain permanently in the air, water, and soil, which is why they are often referred to as "forever chemicals."
Research has indicated that they are connected to some problems that people may experience, such as low birth weight,
high cholesterol, thyroid disease, and an increased risk of certain cancers
.
A study published earlier this month found that
exposure to elevated levels
of PFOS—a type of PFAS once used to make items such as clothing and food packaging resistant to stains, grease, and water— was associated with an increased risk of liver cancer.
Its sister chemical, PFOA, has been linked to an increased risk of kidney cancer.
For this reason,
scientists have spent years trying to find ways to eliminate
PFAS, an acronym for perfluoroalkyl and polyfluorinated substances.
Researchers at Northwestern University released a study Thursday showing that PFAS can be
destroyed using two relatively harmless chemicals
: sodium hydroxide, or lye, a chemical used to make soap, and dimethyl sulfoxide, a chemical approved as a drug for bladder pain syndrome.
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The drinking water of 2,000 communities in the United States still contains elevated amounts of PFAS substances, which are associated with multiple health problems. NurPhoto / NurPhoto via Getty Images
Previously, the only operational way to break down PFAS was to expose the particles to extremely high temperatures—sometimes exceeding 1,800 degrees Fahrenheit—in an incinerator.
But this energy-intensive process can release harmful chemicals into the environment.
The new method appears to
be safer and more
energy efficient.
Northwestern scientists added PFAS molecules to a solution of bleach and dimethyl sulfoxide and exposed them to temperatures up to 248 degrees Fahrenheit.
The chemicals were broken down into fluoride ions and other harmless by-products.
“A specific portion of these molecules breaks off and triggers a cascade of reactions that ultimately breaks these PFAS compounds down into relatively benign products,” William Dichtel, a Northwestern University chemistry professor and co-author of the study, explained in a call with reporters. study.
PFAS are nearly impossible to destroy due to their strong carbon-fluorine bonds.
Brittany Trang, another co-author,
compared the process of breaking down molecules to breaking a Lego block into pieces
.
Currently, PFAS can leach into the water, but then they have to be destroyed somehow.
If the chemicals are dumped into a landfill or disposed of in an incinerator, they can continue to pollute the environment.
“The current way that people try to dispose of PFAS-containing firefighting foam is to incinerate it, but it has been shown that these incinerators actually just blow PFAS around the community that the incinerator is in,” Trang said. .
"So a method is needed to get rid of PFAS so that it doesn't continue to pollute."
Challenges in drinking water treatment
PFAS were invented in the 1930s and
were used in nonstick and waterproof coatings
for consumer goods beginning in the 1940s and 1950s.
Since then, the chemicals have been found in all kinds of household items, including
carpets, cookware, and personal care products
.
PFOA and PFOS
were largely phased out
of chemical manufacturing in the United States
in the mid-2000s
, but have since been replaced by a new group of PFAS chemicals called GenX.
However, older chemicals persist in the environment, including in drinking water.
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The Environmental Protection Agency published new limits for safe levels of PFAS in drinking water in June.
According to the agency, PFOA levels can be harmful above 0.004 parts per billion, while PFOS levels can be harmful above 0.02 parts per billion.
The agency also set a limit of 10 parts per billion for GenX.
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The EPA then acknowledged in a press release that "
some negative health effects may occur
at concentrations of PFOA or PFOS in water near zero and below EPA's detection capability."
The Northwestern researchers broke down PFAS molecules at higher concentrations than the EPA advises, though they believe the process could remove lower concentrations from the water as well.
However, while the new method was able to break down the PFOA and GenX chemicals, Dichtel said,
PFOS cannot be destroyed in the same way
.
Therefore, researchers are studying other methods for this.
The Environmental Working Group, a research and advocacy group focused on toxic chemicals, monitors contaminants in drinking water and estimated in June that
2,000 American communities had levels of PFAS in their drinking water
that exceeded new EPA limits. .
Sara Dean and her 2-year-old son, Patrick, at their home in Parchment, Michigan, one of the communities that discovered in 2018 that its drinking water was contaminated with high levels of PFAS. The Washington Post / The Washington Post via Getty Im
It will likely take several years for scientists to develop a solution that can be applied in these communities, said Christopher Sales, an associate professor of environmental engineering at Drexel University who was not involved in the new study.
"A lot of the methods used to destroy [PFAS] have not really shown that they can be destroyed at such low concentrations," he said.
If the new approach were to be applied to large-scale water treatment, the water would likely have to go from a treatment facility to an off-site location.
There the PFAS would be extracted and exposed to the necessary mixture of bleach and dimethyl sulfoxide.
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"The big question is whether or not this process can be scaled up," Sales said, adding that other researchers are also looking at ways to destroy PFAS at lower temperatures, perhaps even room temperature.
Overall, the problem may require multiple solutions, Sales said: "I don't think there's a single silver bullet to dealing with PFAS."