University of Auckland researchers have discovered that native flax fibres can remove up to 99 per cent of toxic PFAS from water, offering a sustainable, locally sourced solution to a global contamination problem.

By Vincent Mathews
Technology and Science Writer
Zealandia News

April 1, 2026 — AUCKLAND

A team of scientists at the University of Auckland has made a significant breakthrough in the fight against toxic “forever chemicals” contaminating drinking water worldwide, demonstrating that fibres from harakeke — New Zealand flax — can remove between 70 and 99 per cent of these persistent pollutants from water samples .

The research, led by chemical scientist Professor David Barker and PhD student Shailja Data, offers a promising pathway toward a sustainable, locally sourced filtration technology that could address a growing public health concern. The findings come as New Zealand prepares to ban PFAS from cosmetics by the end of 2026, reflecting increasing global concern about these ubiquitous chemicals .

A Chance Discovery Rooted in Mātauranga Māori

The project began unexpectedly when Barker was helping at his children’s school after harakeke bushes had been cut down. While assisting students with weaving, he spoke with a Māori parent who explained that harakeke has natural water-cleaning properties. While living plants clean water through their root systems, Barker wondered whether the leaf fibres might be adapted for water treatment .

Initial experiments focused on nitrates and phosphates — common agricultural pollutants — but the fibres did not bind sufficiently to these chemicals. However, a separate team of researchers at the university spun off from Barker’s work and began testing harakeke against a more challenging target: perfluoroalkyl and polyfluoroalkyl substances, better known as PFAS .

“Its different chemical properties just seem to be a good match for the harakeke,” Barker said .

How It Works

PFAS are known as forever chemicals because the carbon-fluorine bonds that make them useful in manufacturing also make them virtually indestructible in the environment. These molecules take so long to degrade that scientists cannot even measure the length of time it takes .

The chemicals are used in the production of non-stick frypan coatings, waterproof raincoats, cosmetics such as mascara, and a vast array of other consumer products. While not acutely toxic, PFAS accumulate in the environment and the human body over time, where they are known to impede immune system function .

The University of Auckland team treated harakeke fibres to create a positive electrical charge. When the fibres are shaken with water samples, they attract negatively charged PFAS molecules. In laboratory tests, the method removed between 70 and 99 per cent of the chemicals .

Data explained the process simply: “It pulls [the PFAS] off the water” .

Harakeke fibres possess several properties that make them ideal for this application. They are sturdy and rigid, meaning they do not degrade quickly when immersed in water. Unlike plastic-based filters, they also do not create microplastics — a secondary pollution problem that can arise from conventional filtration materials .

Tackling the Short-Chain Problem

The team has focused particular attention on short-chain PFAS, which are increasingly being used as replacements when longer-chain PFAS are banned. While the molecules are smaller, they persist in the environment just as long — a phenomenon scientists call “regrettable substitution” .

“The short or ultra-short chain PFAS are super difficult to remove,” Data said. Most PFAS treatment methods have been developed for traditional, longer-chain variants, leaving drinking water supplies vulnerable to these newer compounds .

The research has focused on drinking water because this represents a primary exposure route for humans. While testing has shown relatively low levels of PFAS in New Zealand waters to date, PFAS-containing products continue to break down and enter the environment, and the chemicals have already been found in some drinking water supplies .

A Sustainable, Reusable Solution

One of the most promising aspects of the harakeke method is its sustainability. Conventional PFAS removal often uses petrochemical-treated single-use products, which create waste disposal challenges. By contrast, the PFAS captured by harakeke fibres can be washed off using a solvent, producing a concentrated form of the chemicals that can then be destroyed by breaking the carbon-fluorine bonds .

The fibres themselves can be reused for filtration, meaning a potential filter product would be longer lasting and generate significantly less waste than current alternatives .

From Lab to Reality

While the experimental results are promising, the researchers acknowledge that scaling the technology for practical use remains a long-term goal. New Zealand has an advantage in that no PFAS are manufactured domestically, meaning environmental concentrations are lower than in many other parts of the world .

However, Data emphasises that more research is needed to understand the full extent of PFAS contamination in New Zealand. “We have limited data about PFAS in New Zealand — we need to know how we’re getting exposed,” she said. Particular attention is needed for kaimoana, agriculture, and endemic species, as international studies may not be relevant to local conditions .

The team plans further experiments to test how harakeke performs with PFAS at low concentrations and in real-world conditions that include different variables, such as varying ions and organic matter .

“The experiments were in lab conditions — in the real world, there are different variables, different ions, more organic matter — it would be exciting to understand how it performs,” Data said .

A Potential New Industry

Barker sees enormous possibilities for harakeke as a commercial crop, noting that the plant grows across New Zealand and could support an affordable, sustainable, regenerative industry .

“We wanted to use fibres available locally so that if projects were successful then potentially we could develop locally,” he said. “There is a growing group of farmers, small companies and iwi who are very interested in growing harakeke as a commercial crop” .

Harakeke is already being used innovatively by New Zealand companies. Kiwifibre produces carbon-fibre replacement materials from the plant, while Biotenax creates yarns that could replace synthetic fibres. For centuries, Māori have used harakeke and its inner muka fibres to make baskets, traps, cloaks, and other essential items .

“Harakeke is a taonga species,” Barker said. “Working with Māori researchers, I’ve understood how deep the connections with the plants are” .

Global Context

The harakeke research comes amid growing international concern about PFAS contamination. The chemicals have been found in drinking water supplies, soil, and wildlife across the globe, prompting regulatory action in numerous countries. The European Union is considering a broad ban on PFAS, while individual US states have set increasingly stringent drinking water standards for the compounds.

The New Zealand government’s ban on PFAS in cosmetics, effective from the end of 2026, represents one piece of a broader effort to reduce the introduction of these chemicals into the environment .

In Brief

University of Auckland researchers have demonstrated that fibres from harakeke — New Zealand flax — can remove between 70 and 99 per cent of PFAS “forever chemicals” from water samples. The method involves treating the fibres to create a positive charge that attracts negatively charged PFAS molecules, which can then be washed off and destroyed while the fibres are reused. The research emerged from conversations with a Māori parent about the plant’s traditional water-cleaning properties, highlighting the value of mātauranga Māori in scientific innovation. While scaling the technology for practical use remains a long-term goal, the findings offer a promising pathway toward a sustainable, locally sourced solution to a global contamination problem. The team plans further experiments to test the method in real-world conditions and at lower contaminant concentrations.