Last week, a New South Wales Health expert advisory panel delivered its report on the health impacts of PFAS, on the same day researchers confirmed 21 new PFAS chemicals had been detected in Sydney’s tap water<\/a>.<\/p>\n With a Senate inquiry into the extent, regulation and management of PFAS looming<\/a>, some academics are encouraging a rethink on the essential use of these substances.<\/p>\n To better understand how “forever chemicals” work, what the risks are, and what’s being done to address the problems, we sat down with three leading PFAS experts:<\/p>\n Dr Denis O’Carroll, managing director of the Water Research Laboratory at the University of NSW’s School of Civil and Environmental Engineering;Dr Brad Clarke, associate professor in environmental science and analytical chemistry at the University of Melbourne; andDr Jamie DeWitt, professor of environmental and molecular toxicology at Oregon State University.<\/p>\n These researchers, who have a combined six decades of experience in the fields of environmental science, engineering and molecular toxicology, are urging caution around what they’ve called a growing problem.<\/p>\n Have you got a question about PFAS? Dr O’Carroll will join us live from 11am to answer the common questions about forever chemicals.\u00a0<\/p>\n Dr Denis O’Carroll will be joining us live from 11am to answer all your questions about PFAS.<\/p>\n What are PFAS and what are they used for?<\/p>\n Per- and polyfluoroalkyl substances (PFAS) refers to a group of over 14,000 synthetic chemicals used in all sorts of industrial and domestic products since the 1950s.<\/p>\n They’re often used in firefighting foams, pesticides, building materials and electronics, as well as household products such as stain-resistant upholstery, waterproof clothing, cleaning products, cosmetics, food packaging and non-stick cookware.<\/p>\n Danish consumer group Forbrugerr\u00e5det T\u00e6nk detected PFAS in half of the rain jackets it tested in a study earlier this year. (ABC News\/Forbrugerr\u00e5det T\u00e6nk<\/a>\/Freepik)<\/p>\n Dr O’Carrol explains that the chemical properties of PFAS make them very effective at repelling water, oil and dirt.<\/p>\n “It’s a chemical that likes to be at interfaces \u2026 it doesn’t let water through jackets, doesn’t allow wine to stain our carpets,” he says.<\/p>\n “In fires it foams up and \u2026 goes to that interface so that the air can’t get to the oil and keep burning, so it extinguishes the fire rapidly.”<\/p>\n Dr Clarke adds “anything that is advertised as oil- or water-repellent is likely to have a PFAS in it”.<\/p>\n “It has a carbon-fluorine bond, which is very strong, and it doesn’t degrade easily in the environment \u2026 they get the term ‘forever chemicals’ because they don’t really degrade,” he says.<\/p>\n The durability of PFAS means they can persist in the environment \u2014 and in the bodies of humans and animals \u2014 for a long time, and this presents significant concerns.<\/p>\n How do PFAS get into our bodies?<\/p>\n According to the latest National Health Measures survey, most Australians have detectable levels of PFAS in our blood<\/a>.<\/p>\n The most common types detected are perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), and perfluorohexane sulfonic acid (PFHxS), found in more than 85 per cent of the population.<\/p>\n The Australian government’s PFAS taskforce notes these chemicals aren’t directly manufactured in Australia<\/a>, but we do know they are found in products we use and traces have been found in the environment.<\/p>\n PFAS used in firefighting foams at Australian defence bases until the early 2000s have been phased out, but have been detected in groundwater of surrounding communities. (ABC News: Jon Daly)<\/p>\n Dr DeWitt says most people are exposed to PFAS through ingestion \u2014 the water they drink or the food they eat.<\/p>\n Pioneering research by Dr O’Carroll, in collaboration with international scientists, tested 45,000 soil and groundwater samples from around the world, and found “a substantial fraction” had PFAS levels exceeding safe drinking water guidelines<\/a>.<\/p>\n The highest PFAS levels tended to be around known exposure sites, including training areas where firefighting foam had been in high use<\/a>, or around landfills.<\/p>\n Study shows prevalence of PFOA in the environment likely underestimated<\/a><\/p>\n Researchers of a new study into how a type of PFAS breaks down in the environment say their findings underline the need to better monitor a wider range of “forever chemicals”.<\/p>\n Levels of PFAS have also been detected in water filtration plants in Sydney<\/a>, in compost being sold to the public in Western Australia<\/a>, and in the nesting soils of little penguins around Tasmania<\/a>.<\/p>\n Last year, Australia updated its guidelines around safe drinking water<\/a> to reduce the accepted levels of several PFAS chemicals.<\/p>\n Dr DeWitt says less is known about other routes of exposure, such as skin absorption or inhalation.<\/p>\n “But we know that when PFAS are [ingested in food or drink] the bulk of what you take into the body can get absorbed across your intestines and get into your blood,” she says.<\/p>\n “When they are in your blood they can stick to proteins \u2026 that are designed to carry things around your body. So PFAS can get carried around the body.”<\/p>\n Dr DeWitt says once PFAS are distributed throughout the body, they can cross cell membranes and interact with proteins that affect various bodily functions.<\/p>\n “Some of these proteins can affect vitally important processes in our bodies, such as the production and action of hormones, the production of cholesterol. So they can interact with these physiological proteins in the body to produce toxicity,” she says.<\/p>\n The health effects of PFAS continue to be studied, but experts say PFOA and PFOS have the strongest links to cancer. (Source: European Environment Agency)<\/p>\n Researchers say one of the biggest concerns with PFAS is their persistence \u2014 that is, how long they hang around in our bodies.<\/p>\n “Many PFAS get excreted in the urine, so they travel from the blood to the kidneys, where they can get pushed out of the body whenever somebody urinates,” Dr DeWitt says.<\/p>\n But this can take a long time.<\/p>\n For some PFAS, the half-life \u2014 that is, the time it takes for half of the amount ingested to be excreted \u2014 is a matter of hours or days, but for most, it’s years.<\/p>\n “The problem is, even if you have low levels of exposure, you can still build up amounts in your body if what you rake in is greater than what you put out,” Dr DeWitt says.<\/p>\n What are the health risks?<\/p>\n The science on PFAS and the potential impact on human health has been the subject of much public debate in the past few years.<\/p>\n Not all of these 14,000 chemicals have been closely studied. Most research has focused on the effects of well-known PFAS, often in populations who have been exposed to high doses.<\/p>\n What are PFAS chemicals? And what do they mean for our health?<\/a><\/p>\n PFAS chemicals are used in a vast number of waterproof, non-stick and stain-resistant products. But concerns about their environmental and potential health impacts have intensified in recent years.<\/p>\n From that research, PFAS exposure has been associated with increased levels of cholesterol and uric acid in the blood, reduced kidney function, altered immune function and levels of thyroid hormones, delayed menstruation, earlier menopause and lower birth weight.<\/p>\n The Australian Health Department’s PFAS guidelines<\/a> note these differences have generally been small and unlikely to cause significant negative health outcomes.<\/p>\n And less is known about the toxicity of these chemicals at low doses over time.<\/p>\n However, Dr DeWitt notes several large-scale epidemiological studies of people who have been highly exposed to PFAS have led to some concerning findings.<\/p>\n “Right now, PFOA has the strongest evidence of links to cancer, followed by PFOS. For the others, there haven’t been enough studies to understand if they are linked to cancer,” Dr DeWitt says.<\/p>\n “But we also have evidence from experimental studies with animals like mice and rats to support what we observe in exposed people, which gives biological plausibility or credibility to those findings in people.”<\/p>\n Dr DeWitt says there is concerning evidence of links between various PFAS chemicals and cancer. (Supplied: East Carolina University)<\/p>\n The NSW Health advisory panel’s report on PFAS<\/a>, published last week, concluded that “health effects of PFAS appear to be small”, and cautioned authorities to “avoid using currently available epidemiological studies to derive threshold levels due to the higher risk of bias”.<\/p>\n Dr Clarke warns that while more research is needed, there are potential risks we should be mindful of.<\/p>\n “We know that there’s a lot of harm from particular types of pollutants, so I’m talking about cancers, reproductive health problems, impaired immune systems, and neurological damage.<\/p>\n “We’ve seen a 50 per cent decline in male fertility over the last century, which many researchers believe is associated with exposure to chemicals.”<\/p>\n Are some PFAS more dangerous than others?<\/p>\n In a group of more than 14,000 chemicals, not all PFAS are the same.<\/p>\n Researchers use several criteria to evaluate the harm of different PFAS chemicals, including how persistent they are in the environment, whether they accumulate in the bodies of humans or animals, and whether they produce toxicity.<\/p>\n The bulk of the research to this point has focused on the impact of what are known as longer-chain PFAS, including PFOA, PFOS and PFHxS.<\/p>\n The structure of these long-chain PFAS is understood to play a significant role in toxicity, and they are generally highly mobile in water, which means they can travel long distances in the environment.<\/p>\n The molecular structure of different PFAS chemicals. (Supplied: Carnero et al., Foods<\/a>, CC BY 4.0<\/a>)<\/p>\n Certain long-chain PFAS, such as those used in firefighting foams, have been phased out around the world and Australia introduced a ban on PFOA, PFHxS and PFOS in July.<\/p>\n But Dr DeWitt warns that PFAS with shorter carbon chains may still be harmful.<\/p>\n “A short-chain PFAS is as equally persistent in the environment as a longer-chain PFAS. So whether a PFAS has eight carbons or four carbons, it doesn’t break down,” she says.<\/p>\n “The difference is that the shorter-chain PFAS tend to get excreted more rapidly from the bodies of living organisms \u2026 that does mean that they have a lesser opportunity to interact with molecules in our bodies to produce toxicity, but they can still produce toxicity.”<\/p>\n Dr Clarke says there’s still a lot we don’t know about newer PFAS, including their effects on our bodies or the environment.<\/p>\n Brad Clarke is the chief investigator at the Australian Laboratory for Emerging Contaminants at the University of Melbourne. (ABC News: Matthew Holmes)<\/p>\n “But we can reasonably predict that they will be persistent [in the environment] because of that perfluoro\u2013carbon bond, which is very strong,” he says.<\/p>\n “So [while] we don’t have full scientific evidence to demonstrate that it causes an environmental harm, we can reasonably predict that it will, because it has similar properties to things that we’ve already banned or phased out.”<\/p>\n Can we live without PFAS?<\/p>\n Dr DeWitt wants the conversation to focus on what we really need PFAS for, and to consider limiting our use to chemicals that are “essential for the health, safety and functioning of society, and for which there are no alternatives”.<\/p>\n “So, do you have to have a sofa in your house that has a stain-resistant coating? Is it really that difficult to remove stains with soap and water?” she says.<\/p>\n “Do you have to have PFAS in your dental floss so that it glides perfectly between your teeth?<\/p>\n “I think we need to think about the essentiality of chemicals before we put them in products.”<\/p>\n<\/p>\n
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