Polar bears are greasier than you think. Here's why
Polar bears might be greasier than widely believed.
The bears' greasy fur is the secret to the popular species' survival in one of Earth's most punishing climates. The grease, also known as sebum, is made up of cholesterol, fatty acids and compounds that make it hard for ice to attach to the animals' fur.
'The sebum quickly jumped out as being the key component giving this anti-icing effect, as we discovered the adhesion strength was greatly impacted when the hair was washed,' Trinity College Dublin PhD candidate Julian Carolan said in a statement following new research.
'Unwashed, greasy hair made it much harder for ice to stick. In contrast, when the polar bear fur was washed and the grease largely removed it performed similarly to human hair, to which ice sticks easily whether it is washed or greasy,' he explained.
Carolan is the first author of the new research, which was published Wednesday in the journal Science Advances.
A group of international researchers analyzed the fur of six wild polar bears. They then performed a chemical analysis of the grease.
In addition, they measured how well ice sticks to fur, whether water can be shed before it freezes, and how long it takes for water to freeze at temperatures on a given surface, comparing the performance of polar bear fur to human hair and specialist human-made 'skins.'
The analysis revealed a surprise: Polar bear sebum did not have an ingredient found in human hair and in the hair of other aquatic animals, like sea otters.
The finding suggests sebum's presence in polar bears is very important from an anti-icing perspective, they said, shedding new light on our understanding of the species.
'This work not only represents the first study of the composition of polar bear fur sebum, but it also resolves the question of why polar bears don't suffer from ice accumulation,' noted assistant Professor Dr. Richard Hobbs, who is also a Royal Society-Science Foundation Ireland University research fellow in Trinity's School of Chemistry and the AMBER Research Ireland Centre.
In the future, Hobbs, the senior author of the journal article, said the sebum could help humans to develop anti-icing coats that could replace toxic 'forever chemicals' like PFAS.
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Telegraph
5 hours ago
- Telegraph
The chemicals in your drinking water that are harming your health (and how to avoid them)
Forever chemicals are part and parcel of modern life. Whether you're pulling on a waterproof jacket, grabbing a coffee in a paper cup, or unwrapping a takeaway, chances are your body's absorbing them. There's more than 10,000 of these synthetic compounds today, which are prized for their resistance to water, oil and stains. That makes them incredibly useful, but nearly impossible to avoid. First developed in the 1930s in both Germany and the United States, PFAS became widely commercialised in the 1950s when US company DuPont used PFOA (perfluorooctanoic acid) to create Teflon, the world's first non-stick coating. Their chemical structure – bonding carbon with fluorine – makes them nearly impossible to break down. As a result, they can persist in the environment for hundreds or even thousands of years, earning them the nickname 'forever chemicals'. Where are they? This persistence means PFAS are now ubiquitous. They are found in soil, air, drinking water, rainwater, and even the blood of nearly every person on Earth. Why do we need to avoid them? The use of the most dangerous PFAS chemicals, PFOA and PFOS (perfluorooctane sulfonic acid), were phased out in the United States, the UK and many other countries beginning in the early 2000s, after studies linked them to cancer, immune system suppression, thyroid disease, liver damage, developmental delays in children, and fertility issues. However, although they are not used in the manufacture of new products in the UK, those toxic, banned chemicals will never disappear from our environment. They exist in the water we drink and the soil that grows our food. More worrying is that these banned substances have been replaced by newer, supposedly less harmful, forever chemicals. These haven't been shown to cause health problems yet, but that doesn't mean we shouldn't be worried. Dr Dave Megson, a chemistry and environmental forensics scientist at Manchester Metropolitan University, says: 'I'm still concerned about them. We've banned the two chemicals we know the most about, but the replacement chemicals are very similar. They're just less understood and their toxicity hasn't been fully confirmed. That seems to be the loophole because we haven't proven they're harmful yet, they're still allowed.' He thinks they will be banned in time and 'we're just waiting for the toxicological data to catch up. We need time to prove how harmful these new PFAS are.' Ian Cousins, professor of environmental organic chemistry at Stockholm University, thinks that most uses are unnecessary. 'We should not be using them because they're so persistent, and there are alternatives on the market.' Last month, the UK's Environmental Audit Committee launched a formal inquiry into PFAS contamination and regulation across the UK. They're concerned that the evidence showing they harm human health is not being taken seriously enough. The UK is lagging behind most other developing countries when it comes to regulating forever chemicals. The EU is moving forward with a comprehensive proposal to restrict the manufacture, use and marketing of approximately 10,000 PFAS. Currently, the UK has banned several specific PFAS chemicals found in firefighting foams, such as Perfluorooctane Sulfonate (PFOS), banned over a decade ago, and Perfluorooctanoic Acid (PFOA), which will be banned from July this year. It's no surprise, given the UK's lack of regulation that a global study assessing blood serums containing PFAS, found UK concentrations to be amongst some of the highest in the world. But while we are waiting for the UK government to catch up with the rest of the world, there are measures that worried consumers can take to reduce their exposure. Ditch plastic bottles and get a water filter Despite water companies having to dilute contaminated water with purer water or use an alternative source, PFAS are still getting into drinking water. PFAS were found in more than half of samples of Scottish drinking water taken in 2023. PFAS have also been found in both bottled and tap water samples in the UK. The Environment Agency has identified over 10,000 sites across England as high-risk for PFAS contamination, many associated with firefighting foam which contained now banned PFAS. Prof Cousins says that people should be especially concerned if they live near an industrial or military site that may have used firefighting foam in the past. 'That is a particularly nasty PFAS and you don't want to be exposed to it. So if you live in that [kind of] area I would consider getting my water tested and install a water filter.' Several UK sites are under investigation for PFAS contamination from firefighting foam. At AGC Chemicals in Thornton-Cleveleys, Lancashire, over 100 tonnes of PFOA (now a banned chemical) were released between 1950 and 2012, prompting soil and water testing. In Norfolk, RAF Marham is being examined after PFAS were found in local drinking water, with bottled water now being supplied to residents. Duxford's former RAF base, now an Imperial War Museum site, is also being monitored due to potential contamination of nearby aquifers. The most effective water filters for removing PFAS use reverse osmosis, activated carbon, or ion exchange. Reverse osmosis systems can remove up to ninety-nine per cent of PFAS, while activated carbon filters also work well if the filters are changed regularly. Good examples include Berkey Water Filters, which use carbon elements tested for PFAS removal, and the Aquasana OptimH2O, which combines reverse osmosis and carbon filtration. Dr Megson offers some reassurance. 'The UK has some of the most tested and regulated water in the world. In known hotspots water is regularly blended and monitored to stay within guidelines. Get an air filter Carpets might be cosy and warm underfoot but increasingly researchers are raising concerns over them as a hidden source of PFAS. They are often added to carpets to make them stain and water resistant. Walking on them creates dust that can reach breathing height. 'People think of contamination as something outside, but indoor dust is significant. For example, carpets treated with Scotchgard in the 1990s are now breaking down releasing PFAS as the fibres degrade,' says Dr Megson. A recent study led by Dr Scott Bartell at the University of California, Irvine, found that people living with carpets consistently showed higher blood PFAS levels than those with bare floors. His conclusion? Carpets are a significant and underestimated source of exposure. Oliver Jones, professor of chemistry, at RMIT University in Melbourne says that 'if you really want to reduce exposure, you should start by looking at where the largest sources of PFAS to humans are. Evidence suggests it's dust in the air.' He recommends getting an air filter. While a standard mechanical air filter, known as an HEPA filter can trap particulate-bound PFAS (like those stuck to dust), a better choice would be an activated carbon air filter. The critical difference: they can remove gaseous PFAS from the air. For broader protection, a combination of both HEPA and activated carbon filtration is ideal. Activated carbon works by adsorbing chemicals at a molecular level, capturing many volatile PFAS compounds that might otherwise circulate freely in your home. Not all air purifiers are created equal, though. Look for units with large activated carbon beds and a high Clean Air Delivery Rate (CADR). Vacuum with a HEPA filter: a high-efficiency vacuum can reduce PFAS-laden dust. Models like Dyson's Gen5outsize (£1,000) or the more affordable Shark Detect and Empty (£350) both offer strong filtration, though only some include activated carbon filters to trap gases. Swap parchment and foil and consider alternatives to your non-stick pan Parchment paper, wax paper and foil are regular fixtures in most kitchens. They are the kind of supplies people use without thinking twice. But research has found that some of these everyday items may be coated with PFAS. When exposed to high temperatures, especially in ovens or on grills, PFAS can break down and potentially seep into the food. That means cooking something as simple as vegetables in foil, or lining a tray with treated paper, could become a source of unwanted chemical exposure over time. 'There are lots of kitchen items with PFAS, including baking paper, non-stick pans and even dishwasher tablets,', says Dr Megson. 'Not all of them transfer large amounts to your food, but some still do. Some parchment paper contains PFAS. But if you're baking a cake once a month, the exposure is minimal compared to what you get from your diet or potentially your water.' 'It's death by a thousand paper cuts. It might be small amounts, but it all adds up in burger wrappers, coffee cups, dishwasher tablets, makeup and workout clothes,' he says. A simple solution that creates a similar non-stick effect is to coat your pan with butter and cover it with flour. The following retailers provide some PFAS-free alternatives: Green Safe Products, Clondakin Group, Nordic Paper. Stop wearing Lycra leggings to the gym PFAS are also found in a lot of athletic clothing including popular Lycra leggings. They are added to fabrics to make them water and stain resistant, or to help wick sweat away from the skin, which is common in performance gear. A 2022 investigation by Toxic Free Future found that more than 70 per cent of sportswear tested contained PFAS, including items from well-known brands. Researchers at Birmingham University also found that sweating makes it easier for the body to absorb these chemicals into the body. There are plenty of PFAS-free options. Look for those made from natural fabrics, such as organic cotton, hemp and bamboo. These selections represent a range of PFAS-free sportswear options from reputable brands: Patagonia has been working to eliminate PFAS from its products, and offers items like the Cap Cool Daily Shirt. Sweaty Betty's Ultimate Studio Twin Strap Bra Vest is designed without PFAS. PFAS can be used to waterproof outdoor clothing. The performance clothing company Rab has been actively working to eliminate PFAS from its products. As of autumn/winter 2024, approximately 95 per cent of Rab's fabrics with durable water repellent (DWR) treatments are PFAS-free. Patagonia Torrentshell 3L rain jacket and North Face's Resolve 2 jacket are PFAS- free. Opt for natural nails 'I think the cosmetics industry has got away [with it] pretty lightly at the moment, whereas the clothing industry has had to do quite a lot,' said Dr Megson. He is worried about gym users applying make-up. 'I'd expect people to get more exposure through make-up than clothes. A lot of people now wear make-up in the gym because they want to look good while exercising. So they go for the really tough 72-hour formulas because they don't want it to run. The reason it stays on so well is because it's packed with PFAS, which resist sweat and water.' Many everyday cosmetics like nail polish, lipstick, mascara, and foundation contain chemicals PFAS, added because they help make products more durable, waterproof, and longer-lasting. Natural and organic beauty products often avoid these synthetic chemicals altogether. Several UK brands now offer PFAS-free nail varnishes and polishes that focus on safer, non-toxic ingredients. Popular options include Zoya, known for formulas free from harmful chemicals like PFAS and Piggy Paint, which provides non-toxic, water-based polishes safe for sensitive skin. Axiology offers clean beauty products with PFAS-free nail polishes. Ditch ready meals and plastic packaging 'Fast food packaging is another unnecessary use of PFAS. It's done purely for convenience. It's there to stop grease from soaking through. We don't want a greasy stain on our shorts or trousers when we're eating a burger. But in warm, moist conditions, like with a wrapped burger, more chemicals can transfer. So it's an extra load we really don't need,' says Dr Megson. 'Pizza boxes are some of the worst and most unnecessary use of PFAS,' says Prof Cousins. 'Instead of using chemicals to stop the fats from the pizza escaping the box, they should make thicker boxes.' Some PFAS-free alternatives include uncoated paper and cardboard, which are suitable for dry foods like sandwiches and pastries and can be recycled or composted. Bioplastic-coated paper, made with plant-based polylactic acid (PLA), offers compostable options. Containers made from sugarcane byproducts, known as bagasse, are naturally grease- and water-resistant, microwave-safe, and home compostable, making them ideal for takeaway plates and containers. However, the raised awareness about PFAS is having an impact on businesses. McDonald's has committed to eliminating them from its food packaging globally by 2025. While US Tex-Mex chain Chipotle committed to eliminating PFAS from all packaging by 2024 and has made significant progress. Stop using throw-away coffee cups To keep hot drinks from soaking through paper cups, they are lined with a thin layer of plastic-like material. 'These cups contain PFAS,' said Prof Cousins. 'Remember though that not all PFAS are the same. They have short chains unlike the older ones that were banned. These substances have not so far been linked to human health effects. However, they are persistent and will accumulate in the environment, which is not a good thing. Toxicity is about dose, so if they continue to accumulate, they are likely to be a problem in the future.' If you're concerned, a simple way to steer clear is to carry a reusable cup made from materials like stainless steel, glass or silicone. What else we should be aware of? Both Dr Megson and Prof Cousins says that we absorb a lot of PFAS through the food chain. 'I wouldn't eat any fish or shellfish from Morecambe Bay. I wouldn't touch the estuary because it is terribly contaminated, says Prof Cousins. I'd be suspicious of eggs reared at home or in these areas, and home-grown vegetables if you live near a hot spot. I would avoid freshwater fish from polluted rivers.' Strawberries sold in the UK have been found to contain high levels of pesticide residues that include PFAS. A 2022 review of government testing data, analysed by Pesticide Action Network UK (PAN UK), found that nearly all of the strawberry samples, 95 per cent, contained traces of PFAS-related pesticides. Strawberries appear to be particularly vulnerable due to the types of pesticides used, and the fruit's porous surface. Other fruits and vegetables, including grapes, spinach, cherries, and tomatoes were also found to carry PFAS residues. We even ingest PFAS through meat, butter and eggs 'We get a lot of our PFAS in our bodies from our diet,' says Dr Megson. Wastewater sludge or slurry which is used as a fertiliser is packed full of PFAS. Animals grazing on contaminated land or drinking polluted water can accumulate PFAS in their tissues, which then passes up to the food chain to humans. Going organic is the best solution to avoid PFAS. Washing fruit and vegetables thoroughly to try to remove as much of them as possible. Can you remove PFAS from the body? Recent research has shown that donating blood or plasma and taking specific medications can help reduce PFAS levels in the body. A 2022 Australian study found that regular blood donations lowered PFAS concentrations by about 10 per cent, while plasma donations, which remove more of the protein-bound PFAS, reduced levels by up to 30 per cent over a year. Additionally, clinical trials are exploring the use of cholestyramine, used to lower cholesterol. This medication binds to PFAS in the digestive system, helping eliminate them through the liver. While these methods don't eliminate PFAS entirely, they offer promising ways to reduce the body's chemical burden, especially for those with high exposure. How are microplastics and PFAS linked? PFAS and microplastics can be linked. Microplastics are tiny plastic particles (less than 5mm) that result from the breakdown of larger plastic waste or are manufactured at that size, commonly polluting oceans, soil, and even food. PFAS can bind to or coat microplastics in the environment, effectively hitching a ride on these tiny plastic particles. This combination may increase the potential for PFAS to enter the food chain, as microplastics are ingested by marine life and other organisms. So while they are chemically distinct, they can interact and amplify each other's environmental impact.
The Guardian
2 days ago
- The Guardian
Scientists warn against attempts to change definition of ‘forever chemicals'
A group of 20 internationally renowned scientists have issued a strong warning against attempts to narrow the definition of 'forever chemicals' in what they describe as a politically or economically motivated effort to weaken regulation of the potentially harmful chemicals. Per- and polyfluoroalkyl substances (Pfas) are a large group of synthetic chemicals used for their oil-, water- and stain-resistant properties in a range of consumer and industrial products from waterproof clothing and non-stick cookware to firefighting foams and electronics. Their molecular structure makes them resistant to degradation, earning them the nickname 'forever chemicals'. In the last few years there has been growing awareness of the problems associated with Pfas, and a push for more stringent regulation, resulting in the banning of certain forms. A group of scientists are now raising the alarm about efforts, including by some individuals and groups in the International Union of Pure and Applied Chemistry (IUpac), to narrow the current international definition of Pfas in ways that could exclude certain chemical subgroups. Last year IUpac launched a project aimed at providing 'a rigorous definition … and a harmonised communication on Pfas'. A paper authored by the chair of the project gives credibility to narrower classification proposals and says it is necessary to find 'a balance among scientific rigour, economic considerations, and social perspectives for effective Pfas regulation'. But in a paper published this week in Environmental Science & Technology Letters, the group of scientists defends the current definition, calling it 'scientifically grounded, unambiguous, and well-suited to identify these chemicals'. The effort to change the definition is 'politically and/or economically, rather than scientifically, motivated', the authors write. 'They are mixing up the chemical definition of Pfas with a regulatory definition of Pfas,' said Prof Ian Cousins from the University of Stockholm. 'The OECD [Organisation for Economic Co-operation and Development] definition was not intended to be a regulatory definition … the confusion it causes will also be damaging and I suspect that causing confusion is one of their objectives.' The authors warn: 'An IUpac-endorsed and potentially narrower Pfas definition could confer undue legitimacy … and influence regulatory bodies and others to adopt less protective policies.' If the definition of Pfas were narrowed, it could drastically reduce the scope of regulation regimes currently being worked out in the EU and UK, limiting the number of substances subject to control, undermining monitoring efforts and potentially weakening public health and environmental protections, according to the scientists. Prof Pierangelo Metrangolo, co-chair of the IUpac project, said 'the scientific rationale was the vibrant debate in the literature – reflecting differing opinions – and the fact that various regulatory agencies use different definitions. Therefore, we believed an IUpac project was timely. 'Currently, the TG [task group] has not finalised any conclusion, yet, and there are no indications that certain subgroups of chemicals would be excluded. More importantly, the IUpac has not 'endorsed' anything, yet.' Prof Alex Ford from the University of Portsmouth, said: 'Chemical industries and their lobbyists have used deny, deflect, sow doubt and delay tactics in the past to prevent and slow regulation on chemicals. 'The UK is still in the process of deciding how it will deal with Pfas compounds. Past experience has shown that confusion over the definition of harmful contaminants can cause substantial delays in their scrutiny and regulation.' The Department for Environment Food and Rural Affairs said it generally followed the OECD definition but that it did not discount the need for narrower definitions in certain contexts. In their paper, the scientists conclude by urging policymakers to continue using the OECD definition as the basis for harmonised regulation. 'Justified exemptions can be made … without changing the general definition of what constitutes a Pfas,' they write.
Daily Mirror
2 days ago
- Daily Mirror
Scientists baffled after finding 6,000 year-old skeletons with no link to humans
The discovery, made in the Bogotá Altiplano of Colombia, has complicated the already-debated story of South America's first inhabitants - who were thought to have crossed from Siberia into North America A mysterious group of ancient hunter-gatherers has left researchers puzzled after DNA analysis revealed they were genetically unlike modern humans. The discovery, made in the Bogotá Altiplano of Colombia, has complicated the already-debated story of South America's first inhabitants. While some theories once proposed that humans reached the continent through transoceanic voyages from Africa or Australia, the dominant view holds that early settlers crossed from Siberia into North America via an Alaskan ice bridge roughly 20,000 years ago. From there, successive waves of migration are believed to have moved southward. The earliest confirmed human remains in South America, including 'Luzia' - a 12,000-year-old skeleton found in Brazil - show ancestry linked to this migration. A second wave of migrants arrived around 9,000 years ago, and a third about 5,000 years after that. However, Colombia, the gateway between Central and South America, has been largely overlooked in ancient DNA studies - until now. Researchers analysed the remains of 21 individuals buried across five archaeological sites in the Bogotá highlands, with skeletons dating from 6,000 to 500 years old. The results, published in the journal Science Advances, were unexpected. 'We show that the hunter-gatherer population from the Altiplano dated to around 6000 yr B.P. lack the genetic ancestry related to the Clovis-associated Anzick-1 genome and to ancient California Channel Island individuals,' the study reports. 'The analysed Preceramic individuals from Colombia do not share distinct affinity with any ancient or modern-day population from Central and South America studied to date.' This means the group that first settled the high plains around Bogotá did not descend from the Clovis people, nor did they contribute genetically to later South American populations. Their DNA appears unique - and then it disappears entirely. The group seems to have vanished roughly 2,000 years ago, possibly as a result of incoming migration. DNA evidence shows that by this time, a new population had taken over the region - one that brought with it agriculture, pottery, and Chibchan languages still spoken in parts of Central America today. 'The genes were not passed on,' said Kim-Louise Krettek of the University of Tübingen. 'That means in the area around Bogotá there was a complete exchange of the population.' This genetic turnover coincides with the cultural shift from the Preceramic period to the Herrera period. The study describes this as a 'seemingly complete replacement' of the region's original inhabitants. 'That genetic traces of the original population disappear completely is unusual,' added Andrea Casas-Vargas of the Universidad Nacional de Colombia.
