Madjid Mohseni, left, professor of chemical and biological engineering, and postdoctoral fellow Ehsan Banayan Esfahani examine a pilot water treatment system in March. University of British Columbia photo by Lou Bosshart

Canadian researchers say they have developed a method to filter toxic “eternal chemicals” from water and potentially destroy the long-lasting compounds permanently.

Better known as “chemicals forever” Because they can persist in the environment for years, these dangerous compounds have long been of concern to environmentalists and regulators. Their deleterious effects on human health are well documented, but their ubiquitous use and difficulties in eliminating them have complicated efforts to eradicate them.

The pressure to do so is increasing. In March, the Environmental Protection Agency proposed the nation’s first drinking water standards that require water utilities to reduce PFAS levels: perfluoroalkyl and polyfluoroalkyl substances.

The new technology, described by one of its developers as a “Brita filter, but a thousand times better”, could help solve the problem, experts say.

“The potential impact will be huge”said Madjid Mohseni, a chemical and biological engineering professor at the University of British Columbia who led the research. “We look forward to taking this as part of the collective toolkit we have to combat PFAS contamination in our water supplies.”

The ace Polyfluoroalkyl and perfluoroalkyl substances are a class of thousands of different chemicals with varying properties.. The highly durable chemicals have been used for decades to make nonstick cookware, water-repellent fabrics and flame-retardant equipment, and are found in other commonly used consumer goods such as cosmetics and food packaging.

Several US states and other countries have banned certain types of PFAS, and many major companies claim to have discontinued their use, but the compounds have appeared in community water supplies across the country and around the world. The chemicals have been linked to infertility, thyroid problems and various types of cancer.

Water samples with different concentrations of contaminants.  University of British Columbia photo by Lou Bosshart
Water samples with different concentrations of contaminants. University of British Columbia photo by Lou Bosshart

Technologies to remove PFAS from water already exist, but Mohseni and other experts say these approaches have limitations.

Activated carbon, for example, can filter out so-called long-chain PFASs, but it doesn’t trap the shorter-chain variants of the chemicals as effectively. Short-chain PFASs, some of which can be toxic in low doses, are becoming more common as many manufacturers use them as replacements for long-chain compounds.

Existing methods also often create waste that contains high concentrations of PFAS, which often end up in landfills or are incineratedsaid Erik Olson, senior strategic director of the Natural Resources Defense Council.

Landfills, harmful chemicals could return to the environment. Burning them isn’t ideal either. “Only incineration at extremely high temperatures can begin to destroy PFAS,” Olson said. “Normal combustion just sends PFAS up the chimney.”

Mohseni said that the material developed by his team, which looks like small porous plastic balls, can remove both long and short chain chemicals at rates that meet or exceed industry standards. The PFAS it captures could be removed, also making the beads potentially reusable or recyclable, he said.

Additionally, Mohseni said, the team developed techniques designed to break down the remnants of PFAS into harmless compounds.

The beads could eventually be used in products to filter water in homes, industrial sites and at the municipal level, he added. However, for home applications, users would have to send used filters to centralized locations for regeneration or recycling, and for PFAS to break down completely, something like some used coffee pods are sent back to manufacturers for recycling, said Mohseni.

General view of one of the two laboratories where the Mohseni group works.  University of British Columbia photo by Lou Bosshart
General view of one of the two laboratories where the Mohseni group works. University of British Columbia photo by Lou Bosshart

His team’s findings have been published in several peer-reviewed journals.

Although the technology shows promise, experts not involved in the research say it has yet to be demonstrated in real-world, large-scale conditions. The UBC research team has started pilot trials in British Columbia, but none of the sites are yet sources of drinking water.

“We are very far from really having a clear solution”says Olson. “Our biggest concern remains that we don’t know exactly how to completely and effectively destroy PFAS on a commercial scale.”

Removing chemicals from water and breaking them down is only part of the solution to the PFAS problem, said Cora Young, an associate professor of chemistry at York University in Toronto who studies chemicals.

“Destroying PFAS that already exist is a useful thing, but many other approaches must be used to really reduce their impact as an environmental problem”said Young.

This includes regulations and other efforts to hold polluters accountable.

“The gold standard is to stop making these things,” Olson said, “and so we’re not polluting the whole environment with it.”

(c) The Washington Post

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