The presence of “forever chemicals” like per- and polyfluoroalkyl substances (PFAS) in various environmental mediums, including drinking water, sea foam, rainwater, and even human blood, has spurred intensified efforts to detect, remove, and neutralise them.

With mounting evidence linking PFAS to detrimental health effects such as cancers, birth defects, and immune system disorders in both humans and animals, there is growing pressure to regulate these versatile waterproofing agents found in an array of products ranging from Teflon cookware and medical devices to cosmetics and food packaging.

Nijhuis Saur industries, a frontrunner in developing technologies to address PFAS contamination, notes the formidable challenges in eliminating and disposing of these substances, even after their banishment.

“They are called the forever chemicals, because they cannot be removed easily, they don’t break down very easily, so they will persist forever,” said Wilbert Menkveld, chief technology officer, at the Aquatech Amsterdam conference. “And we are talking about very small concentrations: one nanogram per litre is like one glass of cola in a million tankers.”

Removing lingering traces of PFAS from water sources poses difficulties due to varying pollutant concentrations and diverse national limits.

For instance, while the UK sets a guideline of 100 nanograms per litre for individual PFAS in drinking water, the Netherlands advises a maximum of 4.4ng/l. The United States Environmental Protection Agency has proposed similar limits for six PFAS chemicals in its “toxicity index.”

Despite ongoing efforts, many PFAS compounds persist in the environment, with no limits set for wastewater.

Dr. David Megson from Manchester Metropolitan University highlights gaps in testing protocols and legislative frameworks, underscoring the urgent need for standardised testing and updated regulations.

“There is no consistency in approach, especially on a global level,” he said. “The US have committed to doing a studies and testing, within Europe there’s a lot going on – in Sweden in particular – and five years ago in the UK we were really behind the ball. People are doing more routine monitoring, but the number of PFAS we need to be worried about has gone from two, to 17, to 47 and now we could have 14,000. By the time a two-year monitoring programme has been performed, it’s almost obsolete.”

Contributors to the Forever Pollution Project identify numerous manufacturing facilities and over 2,100 sites across Europe as PFAS hotspots.

Legal actions, including settlements totalling billions of dollars from companies like Chemours, DuPont, and 3M, reflect the financial toll of PFAS contamination on public water systems. However, remediation efforts remain complex and costly.

Treatment methods vary based on the type and combination of pollutants, as well as the desired outcome of separation or destruction. Established technologies like nanofiltration, reverse osmosis, and granular activated carbon filtration offer viable solutions for removing PFAS from water.

“The longer the chain is, the better it absorbs; short chains are quite hard to reach, so you need a very selective [technology],” said Menkveld. “You can concentrate PFAS, but you have to have a destruction technology at the end.”

Advanced coagulation methods and ion exchange resins can further concentrate and isolate pollutants, although disposal of concentrated waste remains a challenge.

“You need to have different solutions each and every time,” said Menkveld.

Efforts to neutralise PFAS waste include electrochemical oxidation, supercritical water oxidation, and high-temperature incineration.

Dr. Madeleine Bussemaker of the University of Surrey is pioneering an ultrasound-based method, sonolysis, to break down PFAS molecules into harmless byproducts.

“We have seen that ultrasound works with other organics or different cell concentrations: the next step is going to the bigger scale and employing it in real life,” she said. “An American study has shown hydrofluorocarbons around the incineration location: you don’t want to create another pollution stream that you have to deal with later. Sonolysis breaks down those bonds using sound waves.”

Despite these advancements, global stakeholders, including scientific bodies like the Royal Society of Chemistry and regulatory agencies such as the Health and Safety Executive, stress the need for continued research and action.

In Europe, impending directives and proposed bans signal a renewed commitment to tackling the PFAS crisis at both national and international levels.

“Funding, legislation and awareness all go hand in hand,” said Bussemaker. “One of the most alarming things for me is that in order to find a blood sample that does not have PFAS in it, one study had to get blood from [1948-1951 American] Korean war soldiers … it’s not going to go away on its own.”