You might not have heard of per- and polyfluoroalkyl substances, but you’ve almost certainly been exposed to them.
PFAS, as they’re better known, are used in a vast number of waterproof, non-stick and stain-resistant products.
Most of us unknowingly ingest or inhale PFAS chemicals, or rub them on our skin. But concerns about the environmental and potential health impacts of these chemicals have intensified in recent years.
In August, a parliamentary inquiry was called into PFAS to investigate its sources, potential consequences and the role of regulation.
“These chemicals already affect every single person in the world, yet not enough is being done to manage our exposure to them and reduce the risks,” Victorian senator Lidia Thorpe, chair of the inquiry, said.
So what do we know about the health effects of PFAS chemicals, and how worried should we be?
What exactly are PFAS chemicals?
PFAS are a class of almost 15,000 synthetic chemicals known for their ability to effectively resist heat, stains, grease and water.
In addition to being used for industrial purposes, such as in firefighting foams, pesticides, building materials and electronics, they’ve been found in a dizzying array of household and personal care products.
These include (but are not limited to) carpets, rugs, furniture, bedding, upholstery, cookware, food packaging, cleaning products, toilet paper, cosmetics, tampons, sanitary pads, dental floss, contact lenses, clothing, rain coats and shoes.
The exceptional durability of PFAS chemicals – which contain virtually unbreakable carbon-fluorine bonds – is also what makes them ‘forever chemicals’, says Martyn Kirk, professor of applied epidemiology at the Australian National University.
“They are essentially indestructible … and breaking them down takes a long, long time.”
This means PFAS chemicals can persist in the environment for decades, polluting waterways, soil and air, and build up in the bodies of animals and humans over time.
Two of the best-known types of PFAS are PFOS (perfluorooctane sulfonate), previously used in Scotchgard and firefighting foams, and PFOA (perfluorooctanoic acid), historically used to make Teflon cookware.
Today, both chemicals are recognised internationally as being toxic to humans and wildlife and have been discontinued (or are being progressively phased out) in many countries, including Australia. They still, however, remain in the environment and can be found in some imported commercial and consumer products.
In their place, manufacturers have developed new PFAS formulations, many of which we know little about, according to Nick Chartres, who studies the commercial determinants of health at the University of Sydney.
“They’re meant to be used as a substitution, and they’re meant to be less harmful,” Dr Chartres says.
“But very rarely do we get all the safety data on these chemicals.”
How much PFAS are we being exposed to?
Most people in Australia, according to the government’s PFAS Taskforce, have detectable levels of PFAS in their blood.
“We have a ubiquitous exposure, and when we look at people who live even in remote parts of Australia, we still find they have PFAS in their blood,” Professor Kirk says.
In some places, such as firefighter training grounds and defence force bases, the risk of exposure is much higher due to the historical use of toxic firefighter foams. Increased levels of PFAS have also been found near sewage treatment plants, landfills and airports.
Outside known contamination spots, the PFAS Taskforce says it’s unlikely elevated PFAS levels would be found in the environment.
But the recent detection of PFAS in water filtration plants across Sydney has some experts, including Western Sydney University environmental scientist Ian Wright, concerned that PFAS contamination could be much more widespread.
Dr Wright recently co-authored a study that found high levels of the forever chemicals in eight dead platypuses collected from several locations across NSW, including previously unknown PFAS hotspots.
“I do not think we are doing adequate investigations for PFAS,” Dr Wright says.
“I think we have a silent contamination crisis with PFAS creeping into rivers, groundwater, landscapes and ecosystems.”
For people in PFAS-affected areas, the highest risk of exposure is likely to be through consumption of contaminated groundwater and food grown using contaminated groundwater.
Outside these areas, most of us are exposed to low levels of PFAS through products that contain the chemicals or from eating food and drinking water with PFAS in it.
Research suggests dietary exposure to PFAS in Australia is low: in the most recent Australian Total Diet Study, researchers tested for 30 different types of PFAS in 112 commonly eaten foods, and found only one type – PFOS – in low levels in less than 2 per cent of foods.
A 2019 Australian study, co-authored by Prof. Kirk, also found PFAS levels had declined in the Australian population over the past 20 years in line with changes to chemical manufacturing. However, only a handful of PFAS chemicals (including PFOS and PFOA) were measured.
Australian researchers recently found 107 types of PFAS in more than 100 household products.
What do we know about the health impacts?
The relationship between PFAS exposure and human health effects is contested among scientists and public health experts, and scientific evidence remains limited.
Studies have consistently found associations between PFAS exposure and increased cholesterol, reduced kidney function, modified immune and liver function, altered levels of thyroid and sex hormones, lower foetal weight, delayed menstruation and earlier menopause.
But these health effects are “generally small and within normal ranges for the whole population”, according to an expert panel established by the Department of Health in 2017.
The panel, which was convened to advise the federal government on the potential health impacts of PFAS, concluded there was “mostly limited or no evidence for any link with human disease from these observed differences”.
Some animal PFAS studies have found adverse health effects, but often at doses much higher than what humans are typically exposed to. Inconsistent findings in human studies have also created a confusing picture, Prof. Kirk says.
One of the key challenges for researchers studying PFAS is the ubiquity of our exposure. It can be difficult to track – and separate – the effect of different chemicals at different levels when they are all around us, not to mention how they might interact with each other.
Most research has focused on assessing the impacts of just a handful of well-known PFAS chemicals, often in populations exposed to high doses. There is less information about the toxicity of these chemicals at low doses over time.
In populations with an increased risk of PFAS exposure (such as through occupational hazards or community contamination), exposure to PFOA and PFOS has been associated with an increased risk of testicular and kidney cancer.
And in 2023, the International Agency for Research on Cancer (the cancer agency of the World Health Organization) classified PFOA as carcinogenic and PFOS as possibly carcinogenic.
When Prof. Kirk and his colleagues investigated the health impacts of PFAS in three communities with known contamination in Australia, they found limited evidence of adverse health outcomes, aside from increased rates of psychological distress.
“For many chemicals, we expect to see what we call ‘dose response’, meaning the higher the dose, the greater the response to that chemical. But we haven’t seen that here [in Australia],” Prof. Kirk says.
He adds the “huge array” of PFAS chemicals and the multi-factorial nature of many diseases (caused by a combination of genetic, environmental and other risk factors) makes the evidence “very difficult to sort out”.
“While there are signals of concern there … [they] don’t look particularly strong compared to what we see with other chemicals and exposures we regularly have.”
Should I be concerned about PFAS in drinking water?
Reports of PFAS chemicals being detected in water filtration plants across Sydney last month have prompted the closure of a Blue Mountains dam while authorities investigate, as well as further testing across the state.
According to Sydney Water, PFAS levels in the city’s drinking water – which is diluted and filtered before it reaches our taps – remain within national water standards, and therefore safe.
But some experts, including Dr Chartres, believe Australia should adopt stricter standards like those recently introduced in the United States, where water providers are now mandated to reduce PFAS levels to near zero.
“The US Environmental Protection Agency have done a multi-year investigation … and they say there is no safe level [of PFAS exposure],” Dr Chartres says.
“We should not be accepting any level of risk.”
But Nick Osborne, an epidemiologist and toxicologist from the University of Queensland, says setting limits on PFAS levels is “pretty arbitrary” and that Australian guidelines are likely to be “well above what’s safe”.
“[Standards] are there to protect the public and it’s quite right to do that … But the debate becomes: if the chemical is present at all, is that [level of regulation] enough?,” Dr Osborne says.
“Finding a chemical in a water body is one thing. It being at sufficient levels to actually do any harm to humans is quite a different thing.”
A review is currently underway into Australia’s drinking water guidelines, including the thresholds in place for PFAS chemicals.
If you are concerned about your drinking water, Dr Wright recommends asking your local water supplier for their latest test results.
“I drink untreated water from the tap,” he said. “[But] if you are concerned, I would think about a water filter.”
How else can I reduce my PFAS exposure?
Despite the uncertainty around the health impacts of PFAS, experts agree that it’s sensible for people to reduce their exposure to forever chemicals where they can.
Research shows stain-proofing products (for example, those used on carpets and sofas) contain high levels of PFAS, so you may want to limit how much you use fabric protectors and other waxes and sealants around your home.
The same goes for waterproof clothing; there’s no need to throw out a perfectly good rain jacket, but the next time you’re in the market for outdoor gear, you might consider a brand that’s PFAS free.
When it comes to cooking, PFAS-coated non-stick pans are considered safe to use. But limiting how often you use plastic takeaway and disposable food packaging can help to reduce your exposure.
The Australian government is set to effectively ban three of the most prominent PFAS chemicals – PFOS, PFOA and PFHxS (perfluorohexane sulfonate) – from July 2025.
Dr Chartres says he hopes the newly launched Senate inquiry will lead to stronger national regulation, including a total ban on non-essential uses of PFAS.
“The only way that we can truly be protected from these chemicals is through regulating the entire family – all 15,000 of them.”
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