New invention turns toxic forever chemicals (PFAS) into harmless molecules

In our quest to discover ways to rid our environment of “forever chemicals,” the focus is now shifting towards a worrying subclass of these pollutants that contain chlorine atoms within their chemical makeup.

These substances, officially referred to as PFAS or poly- and per-fluoroalkyl substances, have been the backbone of numerous products, spanning from potato chip bags to non-stick cookware. 

The durability of these forever chemicals, stemming from their robust fluorine-to-carbon chemical bonds, means they can linger in our environment for an unsettlingly long time.

PFAS are main components of forever chemicals

One of the main contributors to this forever chemical family are chlorinated PFAS. These compounds have various industrial applications such as serving as non-flammable hydraulic fluids and as chemically stable films providing moisture barriers. 

Recent discoveries of these previously unidentified chlorinated PFAS pollutants are now raising new alarm bells. The U.S. Environmental Protection Agency uncovered their presence in wells and tributaries close to a chemical plant in southwestern New Jersey.

Not only have these forever chemicals infiltrated our groundwater supplies across the country, but they have also been implicated in numerous health issues like cancer, kidney disease, and hormone disruption. To combat this, the EPA is now laying down new rules to prompt nationwide cleanup efforts.

New hope for the eradication of PFAS

A recent study led by Professor Jinyong Liu and graduate student Jinyu Gao from UC Riverside has shed new light on this issue. The research, published in the journal Nature Water, explores novel chemical reaction pathways that have the potential to break down and neutralize chlorinated forever chemicals.

Utilizing ultraviolet light and sulfite, Liu’s team managed to break the chlorine-to-carbon bonds, sparking off a chain of chemical reactions that also split carbon-to-carbon and carbon-to-fluorine bonds (see image here). This is a critical development for pollution cleanup efforts, as rapid and near-complete defluorination of PFAS compounds is necessary for this process.

“Our team is examining more pathways and strategies for PFAS degradation, and our ultimate goal is to cut all of the carbon-fluorine bonds to completely detoxify the PFAS pollutants,” said Liu.

Building upon the work that Liu’s team has been conducting since 2016, these new findings offer new hope for the destruction of various PFAS pollutants in contaminated water. Combining the use of ultraviolet light and sulfite, which has been detailed in seven scientific journal papers, the technique looks promising.

How the research team destroys forever chemicals

The process is appealing due to the low cost and availability of sulfite, which is commonly used as a food preservative, and the use of ultraviolet light, a staple in water treatment facilities for the elimination of harmful microbes. Notably, the process yields fluorine ions, commonly introduced to municipal water supplies to support dental health.

There’s no shortage of interest in Liu’s groundbreaking work, especially from industry. His team has partnered with three companies keen on bringing his lab work to a larger scale. They aim to carry out cleanups at US Air Bases and airports under government contracts.

One of the most significant sources of PFAS pollution in groundwater and beneath military air bases and commercial airports is the spillage of fire-suppressing foams. Originally developed by the US Navy in the 1960s to combat aviation fuel fires, these foams have now become part of the problem.

The new study was also co-authored by Professor Yujie Men, grad students Zekun Liu and Shun Che, and UCR postdoc researcher Dandan Rao.

Study uncovered two bacteria that can breakdown PFAS

In another exciting development, Liu, Goa, Men, and Che co-authored a different paper in Nature Water. The report unveiled the discovery of two bacteria species with the capacity to break down chlorinated PFAS compounds. This significant breakthrough gives newfound hope for biological cleanup strategies.

These bacterial species could be a powerful tool in the fight against the harmful effects of chlorinated PFAS, supplementing the chemical strategies that Liu’s team is pioneering. Combined, these approaches might just be the comprehensive solution that scientists, environmentalists, and public health officials have been desperately seeking.

Very successful study, but more work lies ahead

Chlorinated PFAS pollutants have posed an immense challenge due to their pervasiveness and potential health risks. The robust nature of these “forever chemicals,” their resilience in the environment, and their extensive use in various industrial applications have contributed to their widespread presence. Therefore, it’s vital that ongoing research continues to develop effective methods for their complete breakdown and neutralization.

Professor Liu’s work, along with that of his colleagues and graduate students, is pushing the boundaries of our understanding and capabilities in dealing with this pressing issue. Their dedication to discovering innovative, effective, and economically viable strategies is a beacon of hope in the fight against forever chemical pollution.

The techniques and methodologies they’re developing, whether it’s using ultraviolet light and sulfite reactions, or employing the newly discovered bacteria, could be the keys to unlocking more sustainable and cleaner environments for us and future generations.

More about forever chemicals (PFAS)

“Forever chemicals” is a colloquial term used to describe a class of man-made compounds known as per- and polyfluoroalkyl substances (PFAS). These chemicals earned their nickname because they do not naturally break down and can persist in the environment and in the human body for an exceptionally long time.

PFAS were first synthesized in the 1930s and have been produced and used in a variety of industries around the globe since the 1940s. They have been utilized in a wide range of consumer products such as stain- and water-resistant fabrics and carpeting, cleaning products, paints, cookware, food packaging, and firefighting foams. They’ve been incorporated into these products due to their ability to resist heat, water, and oil.

PFAS are incredibly toxic despite their usefulness 

However, despite their usefulness in industry and manufacturing, PFAS pose significant environmental and health risks. They are highly resistant to degradation, which allows them to persist in the environment for extended periods. They have been found in soil, surface water, groundwater, and even in the air. Some PFAS can accumulate and stay in the human body for many years.

Their extensive use and persistence in the environment mean that PFAS have been detected in the blood of people and wildlife worldwide. They can enter the human body through various routes, including ingestion of contaminated food or water, inhalation of contaminated air, and direct contact with PFAS-containing products.

Some of the health issues caused by forever chemicals

Health studies indicate that exposure to certain PFAS may have harmful effects on human health. These chemicals have been linked to an increased risk of cancer (especially kidney and testicular cancers), impacts on the liver, immune system suppression, thyroid hormone disruption. 

They have also been shown to cause developmental issues in infants and children, including low birth weight and developmental delays. The possible health outcomes depend on various factors such as the type of PFAS, the level and duration of exposure, and individual health and genetic characteristics.

The concern about PFAS has prompted new research to understand these compounds better, to discover ways to safely destroy them or accelerate their breakdown, and to identify safe alternatives. It has also led to regulatory efforts worldwide, including restrictions on their use and requirements for clean-up of contaminated sites.

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