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THIS CONTENT IS BROUGHT TO YOU BY NGI - the Norwegian Geotechnical Institute - read more

PFAS: This could stop the dangerous chemicals from leaking into the environment

Most of the contamination can be contained in the soil for up to a hundred years, researchers believe.

Two researchers in a lab with lots of equipment.

From the right: Michel Hubert from NGI and Björn Bonnet from the Swedish University of Agricultural Sciences analyse soil and water samples for PFAS in the lab.

(Photo: NGI)

Per Olav Solberg Per Olav Solberg Per Olav Solberg Communications Adviser

Presented by: Presented by: Presented by: Norwegian Geotechnical Institute

Published 29 October 2025 - 00:01

"PFAS are extremely stable molecules. They spread easily in nature, are toxic, and can cause serious health effects," says Michel Hubert.

He is a senior engineer in NGI's Department of Environmental Geotechnics, and has recently published and defended his doctoral thesis on PFAS at NTNU.

Portrait of researcher. — "When environmental problems are invisible, they are easy to ignore," says Michel Hubert.

An invisible environmental threat

Since the 1950s, PFAS have been used in everything from firefighting foam and food packaging to rain jackets. They make surfaces water- and grease-repellent, but at a cost: they do not degrade. Instead, they accumulate in nature, and they are now found in blood samples of humans and animals worldwide.

"I often say that global PFAS pollution is just as serious as plastic pollution, which was recently focused in the media due to a possible global plastic treaty. The difference is that we cannot see them. When environmental problems are invisible, they are easy to ignore," says Hubert.

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Sutudies show that there are thousands of PFAS-contaminated sites across Europe, many linked to airports and firefighting training facilities.

In Norway, for example, Oslo Airport is one of the areas with high PFAS concentrations in the soil.

For years, the EU has worked to restrict the use of only a couple few of the most hazardous PFAS compounds – out of a family of more than 10,000. Meanwhile, the industry has managed to create many new variants.

"The result is that policy lags behind reality, the regulations cannot keep up with chemical development," says Hubert.

PFAS – the so-called 'forever chemicals'

What are PFAS?
PFAS stands for per- and polyfluoroalkyl substances – a large group of man-made chemicals used since the 1950s. They make materials water-, fat-, stain-repellent, and heat-resistant.

Where are they found?
PFAS are used in firefighting foam, food packaging, textiles, non-stick cookware, rainwear, and various industrial processes.

Why are they called 'forever chemicals'?
PFAS hardly break down in nature. Many are persistent, mobile, and toxic: They remain in the environment, spread easily through water, and can accumulate in water resources and living organisms.

How many are there?
A few years ago, the estimate by the OECD was about 4,700. More recent research suggests that there are now more than 10,000 different PFAS substances.

Why are they dangerous?
Several PFAS compounds have been linked to health problems such as increased risk of cancer, hormonal disorders, and weakened immune response. They are found in blood samples of humans and animals worldwide – from Oslo to the Arctic and Antarctic.

What is being done?
The EU is now discussing a ban on the entire PFAS family, with exceptions only for "essential use" where no alternatives exist in certain applications, such as specific medical equipment.

Remarkable use of sewage sludge

In his doctoral research, Hubert explored two methods to reduce the spread of PFAS from contaminated soil: soil stabilisation and soil washing.

The most remarkable discovery was that sustainable biochar made from sewage sludge can bind PFAS in the soil for a very long time – while also giving the sludge a new purpose instead of becoming waste.

“Many studies have shown that biochar works in laboratory experiments. We took the research out into the field and left soil mixed with biochar exposed to rain, wind, and snow for a year. The results were just as good as in the lab,” explains Hubert.

Soil washing was the second method. Hubert found that PFAS binds most strongly to the smallest soil particles – clay, silt, and organic matter.

“By separating out the coarser parts such as sand and gravel, the washing process can become more efficient. Equally important is to clean the wash water afterwards. We tested a special product that removed more than 99 per cent of the most hazardous PFAS compounds,” says Hubert.

From research to practice

Hubert stresses that neither method can "wash the world clean" – PFAS pollution is simply too widespread. Measures must be used strategically at the most contaminated sites, and preferably several measures at the same time.

"It's about hotspots – areas where contamination is so concentrated that it threatens drinking water and ecosystems. Airports, industrial sites, old paper mills. That's where we must act. Otherwise, these chemicals will keep spreading," he says.

At the same time, he points out that cleanup is only the final step.

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"Cleaning up PFAS contamination is expensive and demanding. The most important thing is to prevent emissions and reduce use. The EU is now discussing an 'essential use' concept, where PFAS would only be allowed in truly necessary areas, such as medical equipment," says Hubert.

He is now involved in new EU projects and consulting work for industry sites with PFAS problems.

"It's rewarding for me to work with applied research. Using knowledge directly in projects that help address the PFAS problem means a lot. We cannot solve it alone, but we can help prevent the situation from worsening," he says.

Reference:

Hubert, M. Remediation of PFAS-Contaminated Soils and Leachate: An Investigation of Desorption, Removal, and Immobiliziation Processes, Doctoral thesis at NTNU, 2025.