[Today, PFAS are pervasive in soil, dust and drinking water around
the world. Studies suggest they’re in 98% of Americans’ bodies,
where they’ve been associated with serious health problems. There
are now over 9,000 types of PFAS. ]
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HOW TO DESTROY A ‘FOREVER CHEMICAL’ – SCIENTISTS ARE
DISCOVERING WAYS TO ELIMINATE PFAS, BUT THIS GROWING GLOBAL HEALTH
PROBLEM ISN’T GOING AWAY SOON  
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A. Daniel Jones, Hui Li
August 18, 2022
The Conversation
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_ Today, PFAS are pervasive in soil, dust and drinking water around
the world. Studies suggest they’re in 98% of Americans’ bodies,
where they’ve been associated with serious health problems. There
are now over 9,000 types of PFAS. _

How long do we really need chemicals to last?, Sura Nualpradid/EyeEm
via Getty Images

 

PFAS chemicals seemed like a good idea at first. As Teflon
[[link removed]], they
made pots easier to clean starting in the 1940s. They made jackets
waterproof and carpets stain-resistant. Food wrappers, firefighting
foam, even makeup seemed better with perfluoroalkyl and
polyfluoroalkyl substances.

Then tests started detecting PFAS in people’s blood
[[link removed]].

Today, PFAS are pervasive in soil, dust and drinking water around the
world. Studies suggest they’re in 98% of Americans’ bodies
[[link removed]], where they’ve been associated
with health problems
[[link removed]] including
thyroid disease, liver damage and kidney and testicular cancer. There
are now over 9,000 types
[[link removed]] of PFAS.
They’re often referred to as “forever chemicals” because the
same properties that make them so useful also ensure they don’t
break down in nature.
[[link removed]]

Scientists are working on methods to capture these synthetic chemicals
and destroy them, but it isn’t simple.

The latest breakthrough [[link removed]],
published Aug. 18, 2022, in the journal Science, shows how one class
of PFAS can be broken down into mostly harmless components using
sodium hydroxide, or lye, an inexpensive compound used in soap. It
isn’t an immediate solution to this vast problem, but it offers new
insight.

Biochemist A. Daniel Jones
[[link removed]] and
soil scientist Hui Li
[[link removed]] work on
PFAS solutions at the Michigan State University and explained the
promising PFAS destruction techniques being tested today.

How do PFAS get from everyday products into water, soil and eventually
humans?

There are two main exposure pathways for PFAS to get into humans –
drinking water and food consumption.

PFAS can get into soil through land application of biosolids, that is,
sludge from wastewater treatment, and can they leach out from
landfills. If contaminated biosolids are applied to farm fields as
fertilizer
[[link removed]],
PFAS can get into water and into crops and vegetables.

For example, livestock can consume PFAS through the crops they eat and
water they drink. There have been cases reported in Michigan
[[link removed]],
Maine
[[link removed]]
and New Mexico
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of elevated levels of PFAS in beef and in dairy cows. How big the
potential risk is to humans is still largely unknown
[[link removed]].

[Two cows look over a wooden hay trough with a barn in the
background.]

Cows were found with high levels of PFAS at a farm in Maine. Adam
Glanzman/Bloomberg via Getty Images
[[link removed]]

Scientists in our group at Michigan State University are working on
materials added to soil that could prevent plants from taking up PFAS,
but it would leave PFAS in the soil.

The problem is that these chemicals are everywhere, and there is no
natural process
[[link removed]]
in water or soil that breaks them down. Many consumer products are
loaded with PFAS, including makeup, dental floss, guitar strings and
ski wax.

How are remediation projects removing PFAS contamination now?

Methods exist for filtering them out of water. The chemicals will
stick to activated carbon, for example. But these methods are
expensive for large-scale projects, and you still have to get rid of
the chemicals.

For example, near a former military base near Sacramento, California,
there is a huge activated carbon tank that takes in about 1,500
gallons
[[link removed]]
of contaminated groundwater per minute, filters it and then pumps it
underground. That remediation project has cost over $3 million
[[link removed]],
but it prevents PFAS from moving into drinking water the community
uses.

Filtering is just one step. Once PFAS is captured, then you have to
dispose of PFAS-loaded activated carbons, and PFAS still moves around.
If you bury contaminated materials in a landfill or elsewhere, PFAS
will eventually leach out. That’s why finding ways to destroy it are
essential.

What are the most promising methods scientists have found for breaking
down PFAS?

The most common method of destroying PFAS is incineration, but most
PFAS are remarkably resistant to being burned. That’s why they’re
in firefighting foams.

PFAS have multiple
[[link removed]]
fluorine atoms attached to a carbon atom, and the bond between carbon
and fluorine is one of the strongest. Normally to burn something, you
have to break the bond, but fluorine resists breaking off from carbon.
Most PFAS will break down completely at incineration temperatures
around 1,500 degrees Celsius
[[link removed]]
(2,730 degrees Fahrenheit), but it’s energy intensive and suitable
incinerators are scarce.

There are several other experimental techniques that are promising but
haven’t been scaled up to treat large amounts of the chemicals.

A group at Battelle has developed supercritical water oxidation
[[link removed](ASCE)EE.1943-7870.0001957] to destroy PFAS.
High temperatures and pressures change the state of water,
accelerating chemistry in a way that can destroy hazardous substances.
However, scaling up remains a challenge.

Others are working with
[[link removed]] plasma reactors,
[[link removed]]
which use water, electricity and argon gas to break down PFAS.
They’re fast, but also not easy to scale up.

The method described in the new paper
[[link removed]], led by scientists at
Northwestern, is promising for what they’ve learned about how to
break up PFAS. It won’t scale up to industrial treatment, and it
uses dimethyl sulfoxide
[[link removed]],
or DMSO, but these findings will guide future discoveries about what
might work.

What are we likely to see in the future?

A lot will depend on what we learn about where humans’ PFAS exposure
is primarily coming from.

If the exposure is mostly from drinking water, there are more methods
with potential. It’s possible it could eventually be destroyed at
the household level with electro-chemical methods, but there are also
potential risks that remain to be understood, such as converting
common substances such as chloride into more toxic byproducts.

The big challenge of remediation is making sure we don’t make the
problem worse by releasing other gases or creating harmful chemicals.
Humans have a long history of trying to solve problems and making
things worse. Refrigerators are a great example. Freon, a
chlorofluorocarbon, was the solution to replace toxic and flammable
ammonia in refrigerators, but then it caused stratospheric ozone
depletion
[[link removed]].
It was replaced with hydrofluorocarbons, which now contribute to
climate change
[[link removed]].

If there’s a lesson to be learned, it’s that we need to think
through the full life cycle of products. How long do we really need
chemicals to last?[The Conversation]

A. Daniel Jones
[[link removed]],
Professor of Biochemistry, _Michigan State University
[[link removed]]_
and Hui Li [[link removed]],
Professor of Environmental and Soil Chemistry, _Michigan State
University
[[link removed]]_

This article is republished from The Conversation
[[link removed]] under a Creative Commons license. Read
the original article
[[link removed]].

* Science
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* chemistry
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* forever chemicals
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* pollution
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* disease
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* environment
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*
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