Orlando Bloom tried to ‘clean’ his blood to get rid of microplastics – here’s what the science says

Source: The Conversation – UK – By Rosa Busquets, Associate Professor, School of Life Sciences, Pharmacy and Chemistry, Kingston University

Tinseltown/Shutterstock

When actor Orlando Bloom revealed recently that he’d undergone a procedure to have his blood “cleaned”, many people raised eyebrows. The Pirates of the Caribbean star had turned to a treatment known as apheresis – a medical process in which blood is removed from the body, centrifuged or filtered to extract certain components, then returned in an attempt to flush out microplastics and other toxins.

Apheresis is typically used to treat conditions such as autoimmune diseases or abnormally high levels of blood cells or proteins. Its use as a detox for microplastics, however, is scientifically unproven.

Still, Bloom said he suspected his body had absorbed plastic through daily exposure, and wanted it out of his system.

He’s probably right about the exposure. Scientists have found microplastics – tiny plastic fragments less than 5mm in size – in our air, water, soil, food and even inside human tissue. But when it comes to removing them from the bloodstream, that’s where the science gets murky.

As researchers studying microplastic contamination, we’ve examined this issue in the context of dialysis – a life-saving treatment for patients with kidney failure. Dialysis filters waste products like urea and creatinine from the blood, regulates electrolytes, removes excess fluid and helps maintain blood pressure.

But our study found that while dialysis is a medical marvel, it can also have an ironic downside: it could be introducing microplastics into the bloodstream. In some cases, we found that patients undergoing dialysis were being exposed to microplastics during treatment due to the breakdown of plastic components in the equipment – a troubling contradiction for a procedure designed to cleanse the blood.

Apheresis is closely related to dialysis: both involve drawing blood from the body, circulating it through plastic tubing and filters, then returning it – so both procedures carry a similar risk of introducing microplastics from the equipment into the bloodstream.

What are microplastics?

Microplastics are plastic particles that range in size from about 5mm (roughly the length of a grain of rice) down to 0.1 microns – smaller than a red blood cell.

Some microplastics are manufactured deliberately, like the plastic microbeads once common in facial scrubs. Others form when larger plastic objects degrade over time due to sunlight, friction, or physical stress.

They’re everywhere: in the food we eat, air we breathe and water we drink. Plastic packaging, synthetic clothing such as polyester, and even artificial lawns contribute to the spread. Car tyres shed plastic particles as they wear down, and food heated or stored in plastic containers may leach microplastics.

One estimate suggests the average adult may ingest around 883 microplastic particles – over half a microgramme – per day.

So far, large-scale epidemiological studies have not established an association between microplastic exposure and specific diseases. Such studies are needed, but yet to be completed.

However, early research suggests that microplastics may be associated with inflammation, cardiovascular conditions, and DNA damage – a potential pathway to cancer.

What remains unclear is how microplastics behave inside the body: whether they accumulate, how they interact with tissues, and how (or if) the body clears them.

The irony of filtration

It’s tempting to believe, as Bloom seems to, that we can simply “clean” the blood, like draining pasta or purifying drinking water. Just as a sieve filters water from pasta, dialysis machines do filter blood – but using far more complex and delicate systems.

These machines rely on plastic components, including tubes, membranes and filters, which are exposed to sustained pressure and repeated use. Unlike stainless steel, these materials can degrade over time, potentially shedding microplastics directly into the bloodstream.

Currently, there is no published scientific evidence that microplastics can be effectively filtered from human blood. So, claims that dialysis or other treatments can remove them should be viewed with scepticism, especially when the filtration systems themselves are made of plastic.

While it’s tempting to chase quick fixes or celebrity-endorsed cleanses, we are still in the early stages of understanding what microplastics are doing to our bodies – and how to get rid of them. Rather than focusing solely on ways to flush plastics from the bloodstream, the more effective long-term strategy may be reducing our exposure in the first place.

Bloom’s story taps into a growing public unease: we all know we’re carrying the burden of plastic. But addressing it requires more than wellness trends: it calls for rigorous science, tougher regulation, and a shift away from our reliance on plastic in daily life.


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Rosa Busquets receives funding from UKRI, in a UKRI/ Horizons Staff exchanges Clean Water project (101131182). She is honorary Associate Professor at UCL and Honorary Professor at Al-Farabi Kazakh National University. She is panel member of the UNEP EEAP, where is work group lead in a field that includes microplastics. She is also funded by DASA.

Luiza C Campos is a Professor of Environmental Engineering at University College London.

ref. Orlando Bloom tried to ‘clean’ his blood to get rid of microplastics – here’s what the science says – https://theconversation.com/orlando-bloom-tried-to-clean-his-blood-to-get-rid-of-microplastics-heres-what-the-science-says-261203

Mysterious fossil may rewrite story of skin and feather evolution in reptiles

Source: The Conversation – UK – By Valentina Rossi, Postdoctoral researcher, Palaeontology, University College Cork

A delicate, innocuous little fossil reptile known as Mirasaura grauvogeli – “Grauvogel’s wonder reptile” – is forcing a rethink about the evolution of skin and its appendages such as feathers and hair.

These newly discovered fossils, from the Middle Triassic (247 million years old)
Grès à Voltzia site in northeast France, preserve evidence of some of the most astonishing soft-tissue features described to date in ancient reptiles. We are two of the authors of a new paper on these finds, published in Nature.

These fossils show that the tree dwelling Mirasaura had a large and startling crest along its back. The crest is formed by elongated appendages that are neither scales, feathers nor hair.

Until now, complex skin outgrowths such as feathers were thought to have evolved only much later – in birds, dinosaurs and pterosaurs. This probably occurred through a single origin in the common ancestor of these animals. In all other types of reptile, the only skin outgrowths present are scales.

Mirasaura has overthrown this paradigm in sensational fashion. Compared with the size of its body, the long blades of its tall dorsal crest are enormous. Closer inspection reveals this crest comprised individual, overlapping appendages, each with a narrow central ridge and a lobed outline, similar to the shaft and form of feathers.

However, the fossil structures seem to lack the fine branching architecture that characterises most feathers in modern birds. What’s more, Mirasaura is not related to birds, dinosaurs or pterosaurs, but instead belongs to a very ancient group of reptiles, the drepanosauromorphs, that are known only from the Triassic.

A complete fossils specimen of Mirasaura
The holotype of Mirasaura (State Museum of Natural History Stuttgart, Germany) showing its bird-like skull and crest along its back.
Copyright: Stephan Spiekman, CC BY-NC-ND

The soft tissues of Mirasaura are preserved as a thin brown film, rich in fossil melanosomes – cell structures that contain the pigment melanin during life. Research by our team at University College Cork and others has revealed widespread preservation of fossilised melanosomes in ancient vertebrates. These pigment granules can actually be used to reconstruct melanin-based colour patterns in extinct animals.

Our team’s research has shown that fossil melanosomes can also help reconstruct the soft tissue anatomy of fossil animals, because melanosomes from different body tissues have different shapes and sizes. Our comprehensive examination of the fossilised soft tissues in Mirasaura, coupled with rigorous statistical analysis of the preserved melanosomes, reveals that their geometry is consistent with melanosomes in feathers, but not with melanosomes found in hair and in reptilian skin. This strongly suggests the Mirasaura skin appendages share common developmental features with feathers.

Were the Mirasaura structures feathers, then? The solid, continuous blade of soft tissues either side of the central shaft shows no evidence for branching, which is a defining characteristic of most feathers in birds, dinosaurs and pterosaurs. The water is muddied, however, by the simple unbranched structure of some peculiar feathers in birds – such as the bristles of the turkey’s “beard”. Similar unbranched filaments are known in many dinosaurs and pterosaurs, and are widely considered to represent simple feathers.

Certain dinosaur fossils even have flattened, strip-like feathers that lack branching but possess a central shaft, considered by some experts to be an unusual – extinct – feather type. Whether the resemblance between these fossil structures and the Mirasaura skin outgrowths is superficial or belies closer evolutionary ties remains to be seen.

Large isolated crest of Mirasaura
Fossil specimen of a large crest of Mirasaura, hosted by the State Museum of Natural History Stuttgart.
Copyright: Stephan Spiekman, CC BY-NC-ND

Intriguingly, research on the developing chick embryo shows that feathers can lose their branched structure when certain genes are manipulated. We are currently examining in greater detail the morphology and composition of the Mirasaura structures to help us interpret their anatomy more definitively.

Irrespective of what type of skin outgrowth they represent, our analyses of the anatomy of Mirasaura consistently position it, as well as other drepanosauromorph reptiles, at the base of the reptile tree. This supports data from developmental biology indicating that the genetic basis for the growth of complex skin appendages probably originated in the Carboniferous period, over 300 million years ago.

Mirasaura therefore provides the first direct evidence that complex skin appendages did appear early during reptile evolution, and are not unique to pterosaurs, birds and other dinosaurs.

We owe these new insights to painstaking conservation efforts, which serve as a reminder of the critical importance of natural history collections in conserving our natural heritage.

The earliest discoveries of Mirasaura remains were unearthed in the 1930s by fossil collector Louis Grauvogel. After decades in the Grauvogel family, these specimens were donated to the State Museum of Natural History Stuttgart in 2019, where careful preparation revealed their true significance.

Now, the Mirasaura specimens force us to accept that even before the age of dinosaurs, reptiles were evolving striking anatomical traits normally associated with much younger fossils. This adds an intriguing dimension to future research into the origins of feathers, prompting palaeontologists to consider fossils from more diverse reptile groups – and from time periods before the appearance of dinosaurs and their direct ancestors.


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Valentina Rossi research is funded by the European Research Council. She is affiliated with University College Cork (UCC)

Maria McNamara receives funding from the European Research Council and Research Ireland.

ref. Mysterious fossil may rewrite story of skin and feather evolution in reptiles – https://theconversation.com/mysterious-fossil-may-rewrite-story-of-skin-and-feather-evolution-in-reptiles-261695

Trump takes lead role in Cold War Steve’s reimagining of Hogarth’s 18th-century satire, The Rake’s Progess

Source: The Conversation – UK – By Rebecca Anne Barr, Associate Professor in English Literature, University of Cambridge

A reimagining of the sixth cartoon in William Hogarth’s A Rake’s Progress depicting Trump pleading for divine assistance at a gambling den. Cold War Steve

British satirist Cold War Steve has published a series of images based on the British painter William Hogarth’s The Rake’s Progress (1733-35). Hogarth’s 18th-century original charts the catastrophic decline of an affluent young man, Tom Rakewell. Cold War Steve’s 2025 reimagining substitutes the foolish rake with the US president, Donald Trump.

Hogarth’s eight densely packed images are a forerunner of the modern comic script, a kind of condensed graphic novel. The works swarm with life and hidden meanings for viewers to decode.

Tom starts out in high life, flashing his cash and enjoying himself. But he is rapidly drawn into a vortex of late-night drinking, gambling and prostitution. Desperate to save himself from extreme poverty, he sells himself in marriage to an older woman (no cougar, alas, but a rather decrepit heiress).


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But he still cannot control his behaviour. Tom is eventually imprisoned for debt, loses his mind – either to syphilis or sorrow – and dies in Bedlam, the notorious 18th-century madhouse.

Hugely popular and culturally influential, A Rake’s Progress is a modern morality tale. It’s a warning against the perils of self-indulgence, and a devastating critique of those too wealthy and foolish to care about the damage they do.

drawing of men gambling.
The Gaming House, the sixth engraving in The Rake’s Progress, depicts the protagonist back to his profligate ways after marrying an older wealthy woman.
Wikimedia

Political satire as tragicomedy

Keeping close to the original narrative, Cold War Steve uses the 18th-century paintings as backdrops, while altering the object of the satire by making Trump the main target. Renamed Trump’s Progress, this is a pointed political satire, directed at those in power.

Steve’s is a 21st-century reimagining, not a pious homage. Instead, Trump’s Progress has an irreverent punk aesthetic: a horde of Trump-supporting celebrities (such as Don King, Hulk Hogan and Liberace) are photoshopped into his digital canvases, cavorting crazily alongside Trump as he moves from his immense wealth to political pre-eminence.

Cold War Steve's reimagining of A Rake's Progress with Trump as its protagonist.
Cold War Steve’s reimagining of A Rake’s Progress with Trump as its protagonist.
Cold War Steve

Both funny and dark, this is political satire as tragicomedy. The contemporary satirist takes Hogarth as precedent, suggesting a bad end lies in store for the president.

Just as the 18th-century rake ends up in the madhouse, Cold War Steve ends his sequence with an aged Trump lying in a prison cell. Trump is tended to by Israel’s prime minister, Benjamin Netanyahu, and his daughter Ivanka, while his other erstwhile friends look less than pleased to be incarcerated along with him.

Hogarth was a key figure in 18th-century culture. His images of late-night drunkenness , sleazy politicians, and the cheek-by-jowl of luxury living and extreme poverty encapsulated the irrepressible messiness of modern life.

Hogarth reflected Britain’s aspirations to liberty and progress, but also its ongoing struggles with consumerism, luxury, corruption, and greed. These are issues that dominate our present day too, and give Hogarth’s satires an urgent and unsettling relevance.

This is not the first time Cold War Steve has used historical images from the 18th century to indict the present. In a recent article, I explored how Hogarth became a powerful visual source for the satirist during the COVID-19 crisis.

Engravings of poor people drinking beer and gin.
Hogarth’s Beer Street and Gin Lane.
Wikimedia

In May 2020, Steve published an update of Hogarth’s famous print, Gin Lane. The original shows London as a drunken dystopia, as the poor turned to cheap imported gin to ease their daily grind.

But Cold War Steve’s version dramatically altered the image’s moral message. By populating the city street with members of the Tory party and Britain’s business elite, he accused the government of gross moral negligence in treating the pandemic as an opportunity to make money.

The choice of Hogarth is not accidental. Not merely familiar to students of art history, Hogarth has a cultural legibility that makes his work an influential satirical template for artists who want to comment on the social malaise of their times.

Being in conversation with Hogarth gives contemporary works added gravitas. The veteran cartoonist Steve Bell created numerous parodies of Hogarth throughout his time at the Guardian and other publications.

People in a prison
The penultimate scene in A Rake’s Progress, The Prison Scene, shows the vices of the protagonist having caught up with him.
Wikimedia

In 2016, English artist Thomas Moore created a version in which the 18th-century gin craze has been replaced by the obesity epidemic. Hogarth’s impoverished city street is now full of fast food shops, pubs and pawnbrokers. The manic energy and cultural anxiety of Hogarth’s satires resonates with our own accelerated culture and widespread sense of moral and social decline.

In his study of the cultural afterlives of the 18th century, scholar James Ward has shown that postmodern popular culture often invokes Hogarth to question the assumption that our distance from the past is the same as progress.

By splicing together images of the past with the present, Cold War Steve’s visual satires make the serious political point that society has failed to progress since the enlightenment. In his eyes, the vices that Hogarth showed ravaging his society are still part of a culture of political shamelessness, personified by Trump.

Steve’s energetically subversive reworking of 18th-century material shows how Hogarth’s satires continue to be understood and appreciated by diverse audiences.

Former prime minister Boris Johnson portrayed Hogarth as a patriotic British product. But by successfully translating Hogarth’s satires for a transatlantic audience, Cold War Steve shows that his appeal transcends both national and political divides. Current politics might be almost beyond parody on both sides of the pond, but Steve’s bleak humour shows us that satire is thriving.


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Rebecca Anne Barr does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

ref. Trump takes lead role in Cold War Steve’s reimagining of Hogarth’s 18th-century satire, The Rake’s Progess – https://theconversation.com/trump-takes-lead-role-in-cold-war-steves-reimagining-of-hogarths-18th-century-satire-the-rakes-progess-261701

Trump’s budget cuts could shut down local news outlets and reduce reporting on emergencies

Source: The Conversation – UK – By Colleen Murrell, Chair of the Editorial Board, and Full Professor in Journalism, Dublin City University

Donald Trump’s campaign against the “fake news” media continues largely unchecked, with a decision that is expected to reduce reporting and close down some local news stations around the US.

This follows a House of Representatives decision on July 18 to agree with the Senate and slash US$1.1 billion (£813 million) funding to the Corporation for Public Broadcasting (CPB), which manages the money for National Public Radio (NPR), the Public Broadcasting Service (PBS) and their member stations. These cuts will affect the next two years of their operations.

There are fears that some local and rural stations will be forced to lay off staff and may even have to close, if they haven’t amassed significant cash reserves or receive other funding. Don Dunlap, the president of KEDT-TV/FM in Texas, said in an interview: “There are ten public TV stations in Texas, and we’re thinking probably six of them will close down within a year.”

Experts are warning that in national emergencies such as wild fires and floods, local news media are “absolutely essential services” – and that they may not be able to help keep citizens well informed in future. “Nearly three-in-four Americans say they rely on their public radio stations for alerts and news for their public safety,” NPR’s CEO Katherine Maher said .

Trump has had these media outlets in his sights for a while, claiming they are a waste of taxpayers’ money and are ideologically biased against Republicans – a claim denied by NPR and PBS.




Read more:
PBS and NPR are generally unbiased, independent of government propaganda and provide key benefits to US democracy


Public broadcasting regularly sends out alerts related to extreme weather and emergency news. This appears particularly pertinent after the recent Texas floods which killed 135 people. Kate Riley, CEO of America’s Public Television Stations, said local news outlets provide “essential lifesaving public safety services, proven educational services and community connections to their communities every day for free”.

Republican senator from Alaska Lisa Murkowski said she recently received a tsunami warning from her local radio station after an earthquake. Murkowski has tried to introduce an amendment to reduce the cuts to local stations.

The more-than-1,000 NPR stations around the US are vulnerable precisely because significant funding comes from federal sources. According to figures from news organisation Politico: “Approximately 19% of NPR member stations count on CPB funding for at least 30% of their revenue.”

Ed Ulman, president and CEO of Alaska Public Media, told Politico that over a third of public media stations in his state will shut down “within three-to-six months”. He has begun a renewed public funding campaign on social media.

Small rural US radio stations are facing tough budget cuts.

Even at well-funded TV stations such as Arizona PBS, owned by Arizona State University and run by its Walter Cronkite School of Journalism and Mass Communications, some curtailing of plans is afoot. The station provides daily programming to the region, and has trained generations of journalism students to enter careers in TV and radio. Following the announcement of these federal cuts, I spoke to Scott Woelfel, the station’s general manager, who said:

Arizona PBS will lose about US$2.3 million per year over the next two years. That represents around 13% of our total budget. While that is a significant percentage, its loss will not prevent us from operating. In fact, we prepared a reduced budget in the likely event that the rescission would occur, and have been operating under it since July 1 … It contains cuts across the board in an equal amount to the lost revenue.

Following these federal cuts, 60% of the station’s funding will derive from charitable giving, 16% from corporate support and a further 24% from state grants for education services. Woelfel doesn’t plan on making any staff cuts, but said some unstaffed positions will remain open indefinitely – and that the station will be “delaying major new initiatives until new funding is found”.

What happens next?

Overall, these cuts are likely to create additional “news deserts” – regions of the US which don’t have access to important local news and information.

After President Lyndon B. Johnson signed the Public Broadcasting Act of 1967 into law to give funds to public broadcasting, he said: “While we work every day to produce new goods and to create new wealth, we want most of all to enrich man’s spirit. That is the purpose of this act.” But such touching sentiments now seem old-school in this era of Trump’s loud media wars.

In the past week, the US president has also announced he would sue “the ass off” Rupert Murdoch, founder of News Corp, and the Wall Street Journal, which News Corp owns. This follows the WSJ’s publication of a story concerning a 2003 birthday letter framed around the outline of a naked woman that Trump allegedly sent to sex offender Jeffrey Epstein. Trump said the letter was fake. His US$10 billion lawsuit also takes in the WSJ’s owner, Dow Jones, and two of its reporters.

As Trump pushes forward with significant changes to the media landscape, he is no doubt hoping that friendly television stations such as Fox News – also a part of Murdoch’s empire – as well as his influencer following will stay loyal to his brand.

His Maga followers will undoubtedly be supportive of budget cuts and his anti-PBS and NPR statements. But when it comes to reporting from a flood or fire, influencers tend not to be on the ground supplying local residents with up-to-date information. Voters may find those important, and sometimes life-saving, services hard to replace.


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Colleen Murrell received funding from Irish regulator Coimisiún na Meán (2021-4) for research for the annual Reuters Digital News Report Ireland.

ref. Trump’s budget cuts could shut down local news outlets and reduce reporting on emergencies – https://theconversation.com/trumps-budget-cuts-could-shut-down-local-news-outlets-and-reduce-reporting-on-emergencies-261493

Five ways professional athletes are redefining the limits of age in sport

Source: The Conversation – UK – By Paul Hough, Lecturer Sport & Exercise Physiology , University of Westminster

Maciej Rogowski Photo/Shutterstock

In elite sport, the phrase “past your prime” is rapidly being redefined.

At 38, Jess Fishlock just became the oldest goalscorer in UEFA Women’s Euro history. At Euro 2024, Portuguese defender Pepe made headlines not for a red card or faking injury — but for simply stepping onto the pitch at age 41, becoming the oldest player to feature in a European Championship. Fellow veterans Cristiano Ronaldo (39), Luka Modrić (38), and Keylor Navas (38) also made appearances.

And it’s not just football. Serena Williams won the Australian Open at 35 (while pregnant). Roger Federer won a Grand Slam at 36. Rafael Nadal became the oldest French Open champion at 36. Novak Djokovic, now 38, won Olympic gold in 2024 and reached the semi-finals of all three Grand Slams this 2025.

In American sports, Tom Brady retired at 45 after 23 physically punishing NFL seasons. LeBron James, at 39, is still dominating in the NBA, having won the inaugural NBA Cup with the LA Lakers in 2023.

These aren’t just feel-good stories; they reflect a growing trend. Athletes are staying competitive for longer and pushing the boundaries of peak performance. But how?

Research backs the shift. A study on Olympic athletes found that between 1992 and 2021, the average age of male Olympians rose from 25 to 27, and female athletes from 24 to 26. In football, a study of UEFA Champions League players found the average player age rose by nearly two years between 1992 and 2018.

So how are older athletes continuing to thrive in elite sport? Here are some of the key factors.

1. Smarter training

Modern athletes benefit from personalised training programmes informed by cutting-edge sports science. Tools like GPS tracking, heart rate variability (HRV), and biomarker analysis help coaches monitor performance, recovery and injury risk.

Metrics such as HRV, for example, can indicate when an athlete might need more rest, which is crucial for older athletes who take longer to recover after intense competition.

Athletes are no longer reliant on a single coach. Today, they work with integrated teams – sports scientists, strength and conditioning coaches, and performance analysts – all dedicated to improving their fitness and performance.

2. Better injury prevention and medical support

Athletes now undergo regular fitness testing and musculoskeletal screening to identify potential weaknesses before they lead to injury. And when injuries do occur, recovery methods have vastly improved.

Anterior cruciate ligament (ACL) injuries were once considered career-ending for older athletes. But thanks to advanced surgical techniques and biological therapies, recovery is now faster, and athletes return to play much sooner.

Zlatan Ibrahimović, at age 35, returned to top-level football just seven months after an ACL tear – a feat nearly unthinkable a decade earlier.

3. Optimised recovery and nutrition

Ageing athletes have different recovery needs — and sports science has stepped up. Cryotherapy, compression therapy, and advanced sleep protocols all help reduce muscle soreness and accelerate repair.

Nutrition plays a key role too. Ageing bodies experience more inflammation and slower repair, so diets rich in polyphenols (found in berries, leafy greens, and dark chocolate) are used to support vascular health and recovery. Athletes may also take approved supplements such as glucosamine and chondroitin to support joint health and slow degeneration.

The result? Older athletes can train more consistently and recover faster between games.

4. Experience and tactical intelligence

Speed and strength decline with age, but tactical intelligence often improves. Older athletes can compensate for age-related declines in physical capacity with their advanced game-reading skills and spatial awareness. For instance, footballers like Paul Scholes and Andrés Iniesta adapted their playing styles with age, relying more on positioning and passing intelligence than physical capacity.

5. Financial and legacy incentives

Today’s stars aren’t just competing for medals – they’re building brands. With massive financial rewards on offer, there’s a clear incentive to prolong careers.

Cristiano Ronaldo, for example, recently signed a two-year contract extension with Al-Nassr that will see him play until age 42 — reportedly earning an estimated £492 million. For many athletes, the chance to leave a lasting legacy and secure generational wealth keeps them in the game.

While we can’t stop the biological effects of ageing, today’s athletes are proving we can delay their impact – and even thrive later in life.

With smarter training, better recovery strategies and cutting-edge medicine, the upper age limit for peak performance continues to stretch. These advances may allow more veteran athletes to defy expectations and continue competing at the highest level.


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Paul Hough does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

ref. Five ways professional athletes are redefining the limits of age in sport – https://theconversation.com/five-ways-professional-athletes-are-redefining-the-limits-of-age-in-sport-261028

Subsidising e-bikes instead of cars could really kick the electric vehicle transition into high gear

Source: The Conversation – UK – By Noel Flay Cass, Research Fellow in Energy Demand Behaviour, University of Leeds

If you’re thinking of buying a new electric car worth up to £37,000, the UK government has offered to knock up to £3,750 off the price. The measure adds up to £650 million in grants for people to buy EVs (electric vehicles), but as a researcher who studies transport policy and climate change, I think this money would be better spent subsidising e-bikes.

Numerous questions surround the new government policy. Might people who can afford a new car buy one anyway, without the 10% discount? Might car dealers simply reduce the discounts they offer by a similar amount? Given the 20% VAT on an EV, doesn’t a sale actually result in a 200% immediate return for the government? And isn’t this mainly a bung to car manufacturers and company fleets?

The grants come on top of financial assistance for replacing cars, vans, taxis and motorbikes with electric options, announced in February – £120 million in total, including £500 grants for e-motorbikes. But almost no subsidies are available for two-wheeled, pedal-assisted EVs: e-bikes and e-cargo bikes.

The main financial help for buying e-bikes is the cycle to work salary-sacrifice scheme. The employer buys the bike and then instalments are deducted from a participant’s pay before tax, but the scheme’s eligibility is limited to employees on standard payroll tax (PAYE workers) whose sacrifices don’t drop their pay below minimum wage.

This also excludes those who are out of work, the low-paid, the self-employed and retired, arguably people who might benefit most from an e-bike.

Benefits beyond carbon savings

We know that e-bike owners replace lots of trips and miles driven by cars. We also know the upfront cost of around £2,000-£3,000 is a barrier to more people owning one, despite e-bikes being much cheaper than cars.

Estimates of annual carbon savings from e-bikers avoiding car trips vary, from as little as 87kg CO₂ in a 2016 study to 394kg in research published the following year. Estimates published in 2020 and 2023 put the annual climate dividend at 225kg and 168kg of CO₂ respectively – roughly in line with emissions for one person making a return short-haul flight.

A senior woman on an e-bike surrounded in a park.
E-bikes provide extra propulsion to make long or arduous journeys easier for more riders.
Umomos/Shutterstock

These might seem small savings compared to the tonnes of CO₂ that an EV can save. However, e-bike incentives would have two big advantages.

First, policies that encourage active travel, including cycling, have been assessed by the government multiple times to determine the payoff from investment. It turns out that they have huge benefit to cost ratios – 9:1 on average (internationally it’s 6:1).

Conservatively, policies to encourage cycling pay back £5.50 in social benefits for every £1 invested. These benefits are largely savings for the healthcare system. In a project I worked on, in which we lent e-cargo bikes for free to 49 households in Leeds, Brighton and Oxford for several months, e-cargo bike users cycled up to three times more than non-users in our surveys.

E-cargo bike borrowers also reported mental-health benefits on top of satisfaction at being able to combine fitness with functional everyday trips, which were longer than they would attempt on a conventional bike. The cargo bikes especially helped with combining trips – commutes with shopping and school runs, for instance – meaning that more than 50% of trips and miles replaced car usage.

A woman riding a bike with a large cargo hold on the front which a child is sitting in.
Precious cargo.
R.Classen/Shutterstock

Second, e-bike incentives can be designed to appeal especially to the lower-paid, who have been found to use their e-bikes more than wealthier buyers, which would also replace more car trips. The highest of a sliding scale of means-tested incentives in a Canadian study attracted poorer first-time e-bike buyers with existing high car-use.

This reaped average annual carbon savings of 1,456kg for those in receipt of the maximum CAN$1,600 (£868). As the authors suggest, these incentives may have helped low-income households realise their preferences for less dependence on cars.

E-bike grants could get more people out of cars

But how many drivers want to drive less? According to research that groups people into camps based on travel preferences, up to 50% of travellers in the UK are “malcontented motorists” and “active aspirers” (to travel differently).

A man in a suit and helmet attending his e-bike.
Research has shown great potential for wider e-bike ridership.
Halfpoint/Shutterstock

Our research also found that guilt, or trying to minimise car use, was a major motivator for nearly all of our participants. While the government has funded free e-(cargo) bike trials like ours, the main cycling organisations we talked to pointed out that use would “fall off a cliff” when the trial ends because of the cost barrier. Those who would struggle to buy one were back in the same position as before.

A government evaluation of free e-bike loans concluded they were poor value for money, but it tracked purchases made soon after with a tiny response rate. Our project followed up after a year and found 20% of our borrowers had bought an e-cargo bike. Trial loans and grants together might achieve even more.

The new EV grant money could provide nearly 750,000 e-bike or e-cargo bike purchase-incentives the size of the Canadian ones, which could lead to annual carbon savings of 1.125 million tonnes of CO₂, according to the weekly average savings they found in that group.

Given the conservative benefit to cost ratio of 5.5:1 from such a UK scheme, this investment could also reap more than £3.6 billion in social benefits – especially from a fitter car-dependent population. There would potentially be a massive boost to the struggling UK e-bike and e-cargo bike market as well.


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The Conversation

Noel Flay Cass receives funding from UK Research & Innovation grant EP/S030700/1 through the Elevate project: (Innovative Light ELEctric Vehicles for Active and Digital TravEl).

ref. Subsidising e-bikes instead of cars could really kick the electric vehicle transition into high gear – https://theconversation.com/subsidising-e-bikes-instead-of-cars-could-really-kick-the-electric-vehicle-transition-into-high-gear-261429

How the UK’s immigration system splits families apart – by design

Source: The Conversation – UK – By Nando Sigona, Professor of International Migration and Forced Displacement and Director of the Institute for Research into International Migration and Superdiversity, University of Birmingham

arda savasciogullari/Shutterstock

The letter that arrived for eleven-year-old Guilherme in June 2025 was addressed personally to him. The UK Home Office was informing him that he and his eight-year-old brother Luca must return to Brazil. Their parents, an academic and a senior NHS nurse, both long-term UK residents with valid visas were not included in the order.

“Whilst this may involve a degree of disruption in family life,” the letter stated, “this is considered to be proportionate to the legitimate aim of maintaining effective immigration control.”

The family’s difficulties with the Home Office began after the parents divorced a few years after arriving in the UK. Mother and children arrived in the UK as dependants on the father’s visa. After the divorce, the mother secured her own skilled worker visa, while the father was granted indefinite leave to remain in 2024.

Under current rules, skilled workers must wait five years before applying for settlement. For the children to qualify for settlement, both parents must be settled or one must have sole responsibility – neither condition applies here. Only after media attention did the Home Office reconsider the decision.

This case is just the latest example of how barriers to migrants’ family life are embedded in the UK’s immigration system – something I have been studying for years. The Labour government’s recently announced immigration plans extend and bolster these barriers.

Current rules require migrants to earn at least £29,000 to sponsor a spouse or child – a figure set to rise to £38,700 in early 2026 after changes introduced by the last government. The newest immigration plans propose doubling the path to settlement from five to ten years. And they restrict the rights to family reunion to only “nuclear” families: divorced parents, adult children and extended kin are left out.

These changes are aimed at reducing migration and restoring “public trust”. But in practice, they make family unity a luxury — harder to achieve for low-paid migrant workers and even for working-class British citizens with foreign partners.




Read more:
‘Just the rich can do it’: our research shows how immigration income requirements devastate families


The price of family life

Recent research my colleagues and I conducted — based on over 50 interviews with migrant domestic and food delivery workers and other experts — shows how the immigration system fractures families and puts children at risk.

Faith, a Zimbabwean domestic worker, explained how she was unable to bring her eldest daughter to the UK due to age restrictions on dependant visas. Her daughter was later trafficked into the UK and, though she eventually rejoined her mother, hasn’t recovered from the trauma of separation: “She’s struggling to sleep, can’t eat … always emotional, saying she feels dizzy, scared to be around people.”

Faith had been trapped in an abusive relationship for a long time because her visa was tied to her partner. When she eventually left her partner, her visa was withdrawn – leaving her in breach of immigration rules. Her younger child was placed in care while Faith was detained for breaching the terms of her visa.

Jamal, a food delivery rider from Eritrea, had a similar experience of legal dependency. He came to the UK on a dependant visa linked to his British wife. After their relationship deteriorated, his ability to remain in the country was threatened: “If we have problems, she can cancel my visa. This was her weapon.”

Susan, a Zimbabwean woman working in the care and cleaning sector, moved to the UK to look after her adult daughter who had cancer. When her six month visitor visa expired, she applied for asylum, but her application was refused and eventually she was detained for almost a month.

She faced deportation but was released after a legal aid lawyer helped her submit strong evidence of her daughter’s condition. Reflecting on her experience, she explained: “When it benefits them, they say I’ve had no contact [with my family in the UK]. When they want to deport me, they say I have family to return to [in Zimbabwe].”

Immigration status doesn’t just define one’s own legal position, it can determine who gets the right to have a family in the UK and who does not. While some of our interviewees secured status through a partner’s EU citizenship and reunited with family members already in the UK, others who rely on temporary visas are excluded.

Changes to the immigration in recent years have placed a higher value on how migrants can contribute or provide “value” – seeing them as workers (or students) first, not members of families. Many are allowed in the UK for a limited time and without the right to bring with them even the closest family members. The effect is particularly harsh on women in domestic work, whose visas are short-term and not renewable.

Many interviewees reported that immigration barriers delayed or obstructed their children’s education or healthcare. Samantha’s daughter waited over two months for a school placement because their legal status was still pending. Adriana was charged £8,000 for NHS maternity services because of her undocumented status, which restricts access to free healthcare to GP and emergency care.

Even in less extreme cases, legal insecurity takes a toll. Children grow up hearing their parents talk about “papers”, “Home Office letters” or the risk of being “sent back”.

That the Home Office sent a removal letter to an eleven-year-old is not a clerical error. It is the system working as designed. And even when public outrage forces a reversal — as in Guilherme’s case — the wider machinery of enforcement continues.


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The Conversation

Nando Sigona is Scientific Coordinator of “Improving the Living and Working Conditions of Irregularised Migrant Households in Europe” (www.i-claim.eu), a three-year six-country research project, funded by the European Commission’s Horizon Europe and UKRI.

ref. How the UK’s immigration system splits families apart – by design – https://theconversation.com/how-the-uks-immigration-system-splits-families-apart-by-design-261134

Canadian wetlands are treasures that deserve protection

Source: The Conversation – Canada – By Maria Strack, Professor, Department of Geography and Environmental Management, University of Waterloo

The Grande Plée Bleue bog, near Québec City in June 2023. This peatland with pools is one of the largest wetlands in eastern Québec. (Maria Strack)

Though Canada is often known as a land of lakes, it is also a country of wetlands. Stretching like a necklace of emeralds, sapphires and rubies across the Canadian landscape, wetlands cover 14 per cent of the Canadian land mass, accounting for almost twice as much area as lakes.

Canada is home to a quarter of the world’s remaining wetlands, yet they remain like hidden treasures that most Canadians rarely pay a second thought.

The importance of wetlands to a sustainable future has been recognized internationally. Signed in 1971 in the Iranian city of Ramsar, the Convention on Wetlands — often called the Ramsar Convention — supports international collaboration and national action for the conservation of wetlands.

This week, delegations from contracting parties to the convention, including Canada, have come together in Victoria Falls, Zimbabwe, for the 15th Conference of the Parties.

Despite decades of efforts, wetlands continue to be under threat around the world. Delegates will work this week to chart a path forward that further elevates wetlands in the global consciousness, highlighting the need to protect these ecosystems and meet international goals to safeguard biodiversity and slow climate warming.

Canada currently has 37 Wetlands of International Importance under the Ramsar Convention, covering more than 13 million hectares. Yet many of Canada’s wetlands remain unprotected.

Canada’s wetlands

The term “wetland” usually conjures an image of a shallow pond bordered by cattails. In fact, Canadian wetlands come in a range of shapes and sizes, all of which provide valuable services. Those reedy marshes provide critically important habitat and water storage, particularly in the Prairies, southern Ontario and Québec.

The vast majority of Canada’s wetlands are made up of swamps, fens and bogs, most of which also hold deep deposits of organic soils called peat. Bogs and fens can resemble vast mossy carpets. But they can also look a lot like forests, hiding their soggy soils beneath a canopy of trees.

This wetland diversity contributes to their value. At the interface of terrestrial and aquatic ecosystems, wetlands are often biodiversity hotspots.

They are home to weird and wonderful species, including carnivorous plants like sundews, pitcher plants and bladderworts. And if you’re hungry, peatlands are a great place for berry picking.

Interwoven in our boreal landscape, wetlands also support iconic Canadian species like beavers, moose and woodland caribou and are key habitats for waterfowl and other migratory birds.

Preserving wetlands is also a key flood mitigation strategy. Storm water can fill up pore spaces in mossy peat soils, or spread out across the flat expanse of swamps and marshes, reducing peak flows and helping to protect downstream infrastructure. As the water slows, water quality can also be improved. Sediments have time to settle, while plants and microbes can remove excess nutrients.

Carbon storage

In recent decades, wetlands have gained international attention for their role in carbon storage. Waterlogged sediment and soil lead to slow rates of decomposition. When plant litter falls in a wetland, it builds up over time, creating a bank of carbon that can be stored for millennia.

Peatlands are particularly good at accumulating carbon, as they are home to plants that inherently decompose slowly. Because of this, peatlands store twice the carbon of the world’s forests. Keeping this carbon stored in wetland soils, and out of the atmosphere, is important to climate change mitigation.

Yet, the buildup of carbon in wetlands is slow. Many of these ecosystems have been adding to this carbon bank since the last ice age; digging through metres of peat is like travelling back through time, with the deposits at the bottom often thousands of years old.

This means that the carbon stored in wetlands is irrecoverable within human lifetimes. Once lost, it will be many generations before the full value of this treasure can be returned.

The economic value of the water-filtering and carbon storage that Canadian wetlands provide has been estimated at $225 billion per year. It’s clear: healthy wetlands contribute to our society’s well-being.

But just as important, they are an integral component of the Canadian landscape. Wetlands are interwoven with our forests, fields, lakes and now even our cities. They link us to the land and water. They are places of wonder and spiritual connection.

Impact of climate change

Despite their value, wetlands in Canada face many threats. In southern regions of Canada, most wetlands have already been lost to drainage for agriculture and urban development. Further north, up to 98 per cent of Canadian peatlands remain intact.

However, climate change and resource development are already exacerbating wetland disturbance and loss. Warming temperatures have contributed to larger and more severe wildfire that also impact peatlands and lead to large carbon emissions.

Thawing permafrost is further changing wetland landscapes and how they function. Warming also allows for northward expansion of agriculture with the potential for loss of even more wetland area to drainage.

Natural resource extraction further contributes to wetland disturbance, often with unexpected consequences. Geologic exploration used to map oil and gas reserves has left a network of over one million kilometres of linear forest clearing across the boreal forest, much of which crosses peatlands.




Read more:
How climate change is impacting the Hudson Bay Lowlands — Canada’s largest wetland


This has contributed to declines in woodland caribou populations and led to increases in methane emissions from these ecosystems.

Mining often involves regional drainage or excavation of peatlands, resulting in the loss of their services. The recent push to fast-track production of critical minerals in Canada is putting vast areas of our wetlands at risk.

Wetland restoration research is ongoing, with some promising results. However, given the long time-scale of wetland development, avoiding disturbances in the first place is the best way to safeguard wetlands.

As stewards of a quarter of world’s wetland treasures, policymakers and everyday Canadians need to ensure wetlands are safeguarded and preserved for a prosperous future.

The Conversation

Maria Strack receives funding from the Natural Sciences and Engineering Research Council of Canada, Environment and Climate Change Canada, the Canadian Sphagnum Peat Moss Association, Ducks Unlimited Canada, Imperial Oil Ltd., Alberta Pacific Forest Industries Inc., Cenovus Energy, Canadian Natural Resources Limited, ConocoPhillips Canada, Natural Resources Canada, and the Alberta Biodiversity Monitoring Institute.

ref. Canadian wetlands are treasures that deserve protection – https://theconversation.com/canadian-wetlands-are-treasures-that-deserve-protection-261433

Interdire les munitions au plomb pour sauver les oiseaux de l’empoisonnement ? L’exemple britannique

Source: The Conversation – in French – By Deborah Pain, Visiting Academic, University of Cambridge; Honorary Professor, University of East Anglia, University of Cambridge

La majorité des grenailles tirées ne touchent pas leur cible et des milliers de tonnes de plomb se retrouvent dispersées dans l’environnement. Chuyko Sergey/Shutterstock

La Commission européenne a proposé le 27 février 2025 d’interdire l’usage du plomb dans les munitions de chasse. Au Royaume-Uni, une pareille interdiction vient d’être annoncée. Ces mesures devraient permettre de sauver des milliers d’oiseaux mais également de protéger les humains qui consomment du gibier.


Au Royaume-Uni, la sous-secrétaire d’État à l’eau et aux inondations, Emma Hardy, a annoncé l’interdiction des munitions toxiques au plomb afin de protéger les campagnes du pays. Cette interdiction concerne la vente et l’usage, à des fins de chasse, aussi bien des cartouches de fusils chargées de plomb (comportant des centaines de petites billes appelées « grenailles ») et utilisées pour chasser le petit gibier, que des balles de gros calibre en plomb, destinées à la chasse au grand gibier, comme les cerfs.

C’est une excellente nouvelle pour les oiseaux britanniques : cette mesure devrait permettre d’épargner chaque année la vie de dizaines de milliers d’entre eux, actuellement victimes d’empoisonnements au plomb. La majorité des grenailles tirées ne touchent pas leur cible et des milliers de tonnes de plomb se retrouvent dispersées dans l’environnement chaque année. Or, les oiseaux aquatiques comme terrestres les confondent avec de la nourriture ou du gravier, qu’ils consomment pour broyer leurs aliments dans leur gésier. Les grenailles s’y désagrègent et le plomb est alors absorbé dans le sang.

On estime qu’entre 50 000 et 100 000 oiseaux d’eau meurent chaque année au Royaume-Uni des suites de cette intoxication, souvent après de longues souffrances. D’autres oiseaux subissent des effets dits « sublétaux » : leur système immunitaire et leur comportement sont altérés, ce qui augmente leur vulnérabilité face à d’autres menaces.

L’utilisation de grenailles de plomb pour la chasse aux oiseaux d’eau et au-dessus de certaines zones humides est déjà interdite en Angleterre et au Pays de Galles. En Écosse, cette interdiction s’applique à l’ensemble des zones humides, sans exception.

Cependant, le respect de la réglementation en Angleterre n’atteint qu’environ 30 %, et il est également faible en Écosse, tandis qu’aucune donnée n’est disponible pour le Pays de Galles. Cette nouvelle interdiction générale, plus étendue, devrait améliorer considérablement la situation dans tous les milieux naturels à travers la Grande-Bretagne.

Les rapaces comme les aigles, les buses variables ou les milans royaux sont également touchés : ils ingèrent des fragments de plomb en se nourrissant d’animaux tués ou blessés par des munitions en plomb. L’acidité dans leur estomac favorise l’absorption du métal. Nos recherches montrent que, bien que l’on estime que moins de rapaces que d’oiseaux d’eau meurent directement d’un empoisonnement au plomb, les conséquences sur leurs populations peuvent être bien plus graves. Cela concerne en particulier les espèces qui commencent à se reproduire tardivement, dont le taux de reproduction annuel est naturellement faible et qui, en temps normal, bénéficient d’un taux élevé de survie annuelle chez les adultes.

Ce bannissement bénéficiera aussi bien aux oiseaux résidents qu’aux migrateurs de passage au Royaume-Uni. Mais tant que d’autres pays continueront à autoriser ces munitions , les oiseaux migrateurs resteront exposés ailleurs, pendant leur trajet ou sur leurs lieux de reproduction ou d’hivernage.

Au-delà des frontières

Pour protéger toutes les espèces, les munitions au plomb doivent être remplacées partout par des alternatives sans plomb. L’usage de grenailles de plomb est déjà interdit dans de nombreuses zones humides à travers le monde. Dans l’Union européenne, (en France notamment, ndlr), une interdiction de l’utilisation de grenailles de plomb dans ou à proximité des zones humides est entrée en vigueur en février 2023 .

Le Danemark a été le premier pays à interdire les munitions au plomb dans tous les milieux. En 1996, il a interdit l’usage des grenailles de plomb et, en avril 2024, il a interdit les balles en plomb. Nos recherches montrent que l’interdiction des grenailles de plomb au Danemark a été très efficace, avec un bon niveau de conformité.

Le Royaume-Uni s’apprête maintenant à devenir le deuxième pays à interdire la plupart des usages des munitions au plomb. Cela a été rendu possible grâce à la disponibilité croissante d’alternatives sans plomb, sûres, efficaces et abordables, principalement les grenailles en acier et les balles en cuivre.

En février 2025, la Commission européenne a publié un projet de règlement interdisant la plupart des usages des munitions et des plombs de pêche en plomb. Ce projet attend encore l’approbation dans le cadre des procédures de l’UE. S’il est adopté, cela constituera une avancée majeure.

Au-delà des oiseaux

Les oiseaux sont particulièrement sensibles aux effets du plomb issu des munitions qu’ils ingèrent, en raison de leur gésier musculeux et de l’acidité de leur estomac. Mais ce plomb met aussi en danger la santé de nombreux autres animaux, y compris les animaux domestiques et les humains.

Au Royaume-Uni, nous avons trouvé dans des aliments crus pour chiens à base de faisan, provenant de trois fournisseurs, des concentrations moyennes de plomb plusieurs dizaines de fois supérieures à la limite maximale autorisée de résidus de plomb dans les aliments pour animaux.

Le gouvernement britannique a fondé sa décision d’interdire les munitions au plomb sur un rapport de l’agence REACH pour la Grande-Bretagne, ou Health and Safety Executive, qui soulignait les risques pour la santé des jeunes enfants et des femmes en âge de procréer, en cas de consommation fréquente de viande de gibier chassé avec des munitions au plomb. Le système nerveux en développement des enfants est particulièrement sensible aux effets du plomb.

Nous avons récemment appelé le comité des États appliquant la réglementation sur les produits chimiques (REACH), le Parlement européen et le Conseil à soutenir pleinement la proposition de la Commission européenne visant à restreindre les munitions au plomb.

Nous avons également encouragé l’Autorité européenne de sécurité des aliments (EFSA) à recommander à la Commission européenne de fixer une limite légale maximale de plomb dans la viande de gibier commercialisée pour la consommation humaine, similaire à celle déjà établie pour la viande issue de la plupart des animaux d’élevage.

Tant que cela n’aura pas été mis en place, et tant que davantage de pays n’auront pas interdit tous les usages de munitions au plomb pour la chasse, la santé de la faune sauvage, des animaux domestiques et des groupes humains les plus vulnérables continuera d’être menacée par les effets toxiques du plomb issu de ces balles.

The Conversation

Deborah Pain est professeure honoraire à l’Université d’East Anglia (sciences biologiques) et chercheuse invitée au département de zoologie de l’Université de Cambridge. Elle est scientifique indépendante depuis avril 2018. Depuis cette date, elle n’a perçu aucune rémunération pour ses recherches sur l’intoxication au plomb, mais, avec ses collègues, elle a reçu des financements pour couvrir les coûts de la recherche et des analyses chimiques de la part de plusieurs sources, comme indiqué dans les publications scientifiques. Elle a été membre du groupe d’experts scientifiques indépendants du Royaume-Uni pour la réglementation REACH (RISEP), et dans ce cadre, du groupe de travail sur le plomb dans les munitions, ce pour quoi elle a été rémunérée. Cependant, ses travaux publiés sur l’intoxication au plomb ont été réalisés indépendamment de ce processus.

Rhys Green a reçu des financements pour ses recherches de la part de plusieurs organisations, dont la RSPB (Royal Society for the Protection of Birds), au sein de laquelle il a occupé le poste de principal scientifique en conservation jusqu’en 2017. Il est désormais à la retraite. Il est chercheur bénévole non rémunéré à la RSPB et professeur honoraire émérite en sciences de la conservation au département de zoologie de l’Université de Cambridge. Il est membre du groupe d’experts scientifiques indépendants du Royaume-Uni pour la réglementation REACH (RISEP), un groupe mis en place par une agence gouvernementale britannique, la Health & Safety Executive. Il reçoit ponctuellement des paiements pour les travaux réalisés dans le cadre de RISEP. Il siège également au conseil d’administration du zoo de Chester.

Niels Kanstrup ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d’une organisation qui pourrait tirer profit de cet article, et n’a déclaré aucune autre affiliation que son organisme de recherche.

ref. Interdire les munitions au plomb pour sauver les oiseaux de l’empoisonnement ? L’exemple britannique – https://theconversation.com/interdire-les-munitions-au-plomb-pour-sauver-les-oiseaux-de-lempoisonnement-lexemple-britannique-261617

Comment favoriser la réutilisation des eaux usées traitées en France ?

Source: The Conversation – in French – By Jérôme Harmand, Directeur de Recherche, Inrae

Le plan Eau de la France vise 10 % de réutilisation des eaux usées traitées à horizon 2030. Comment y parvenir sans augmenter la quantité d’eau consommée au total – c’est-à-dire, sans risquer un effet rebond ? Panorama des bonnes pratiques identifiées par la recherche scientifique.


En France, le plan Eau annoncé par le président de la République en 2023 affichait un objectif de développement de 1 000 projets de réutilisation des « eaux non conventionnelles (ENC) » en 2027. Il s’agit d’un objectif intermédiaire avant de viser 10 % de réutilisation des eaux usées traitées (REUT) à horizon 2030.

S’il est poursuivi sans suffisamment de discernement, cet objectif quantitatif national pourrait conduire à une maladaptation et à des projets inadéquats. Par exemple, à des projets qui auraient pour conséquence d’augmenter la quantité globale d’eau consommée à la faveur de l’« effet rebond ». Le risque serait de présenter la REUT comme une nouvelle ressource, alors même que cette eau remobilisée est susceptible de manquer aux milieux naturels.

Pourtant, l’état de l’art scientifique et l’analyse des retours d’expériences internationaux confirment l’intérêt du réusage de l’eau pour répondre à des situations de fortes tensions. Ces mêmes expériences démontrent aussi que les projets sont fortement conditionnés par les contraintes locales.

Autrement dit, leur réussite va dépendre de l’implication des acteurs, de l’adéquation entre la qualité de l’eau requise et le niveau de technologie des traitements, de la viabilité économique des projets, etc.

Les eaux usées, une ressource plutôt qu’un déchet

Pour aider nos sociétés à s’adapter au changement climatique et préserver notre environnement, une gestion maîtrisée et responsable de l’eau est essentielle, tant d’un point de vue quantitatif que qualitatif. Il s’agit d’un enjeu stratégique pour assurer des conditions de vie soutenables à tous.

Cela passe notamment par la sobriété et l’optimisation des usages et le partage de la ressource. Surtout, il ne faut pas oublier de prendre en compte de l’état des milieux aquatiques. Par exemple, en considérant le rôle environnemental des eaux usées traitées dans le maintien des débits d’étiage pendant les périodes de sécheresse.

Dans ce contexte, les eaux usées ne doivent plus être considérées comme un déchet à traiter et évacuer, mais comme une ressource. Ces eaux peuvent par exemple être riches en fertilisants utiles aux cultures agricoles. Dans une logique d’économie circulaire, on peut les considérer comme des flux de valeur, en fonction des spécificités territoriales (adéquation entre les besoins des cultures et l’eau disponible, proximité des usages…).

Les eaux usées domestiques constituent la principale ressource pouvant être mobilisée. Il est toutefois nécessaire d’élargir le concept d’économie circulaire de l’eau à l’ensemble des eaux non conventionnelles. Par exemple, les eaux de pluie, eaux de piscine ou encore les eaux évacuées du sous-sol pour permettre l’exploitation d’ouvrages enterrés tels les métros, tunnels ou parkings… Ceci permet d’équilibrer au mieux les usages et les prélèvements à l’échelle d’un territoire.

Boucler le « petit » et le « grand » cycle de l’eau

Pour faire face aux tensions sur la ressource, il nous faut donc inventer de nouvelles approches. L’enjeu est de repenser son utilisation tout au long des chaînes de valeur. Pour cela, on peut imaginer des usages en boucles (réusage après un usage précédent), là où ils étaient jusqu’à maintenant linéaires (mobilisation, utilisation, rejet).

Il s’agit de concevoir une gestion de l’eau plus intégrée à l’échelle d’un territoire, qui va contraindre ressources et besoins. L’objectif est que le cycle d’usage perturbe le moins possible le « grand » cycle (ou cycle naturel) de l’eau, aussi bien quantitativement que qualitativement.

Le contexte agricole, urbain ou industriel a également son importance. Il impose d’examiner les risques environnementaux et sanitaires. En effet, il s’agit de modifier le cycle de l’eau. La mise en place de solutions favorisant des cycles courts peut impacter les milieux et les populations à des degrés divers. C’est particulièrement vrai en périodes de sécheresse sévère.

Par exemple, la qualité microbiologique de l’eau peut poser question dans les situations de réutilisation indirecte. Dans ce cas, l’eau n’est pas prélevée directement en sortie de station (où elle serait alors soumise à des normes de qualité afin d’être réutilisée), mais en aval, dans le cours d’eau dans lequel la sortie de station s’est déversée. Ce type de prélèvement n’est réglementairement conditionné qu’à des contraintes quantitatives, et non plus qualitatives.

Quels sont les projets qui aboutissent ?

L’état de l’art scientifique et l’analyse des retours d’expériences internationaux sont utiles pour identifier les facteurs de réussite de ces projets.

Ils tirent tout d’abord parti d’un contexte géographique favorable. Par exemple, lorsque la distance entre les gisements et les usages potentiels est raisonnable ou que des aménagements hydrauliques existent déjà.

Ils organisent aussi la concertation des diverses parties prenantes concernées (gestionnaires, agriculteurs, consommateurs, financeurs…). L’enjeu est de les impliquer dans la gouvernance pour permettre de mieux aligner leurs intérêts respectifs.

Ils mettent également en place un plan de maîtrise des risques sanitaires et environnementaux, par exemple en adoptant une approche multibarrière.

Ces projets gagneraient à s’inscrire dans un cadre réglementaire et normatif clair et harmonisé, à une échelle dépassant le cadre national afin de tirer parti des retours d’expériences internationaux. À l’exception de la réutilisation à usage agricole, la réglementation sur les eaux usées pourrait être améliorée pour être mieux calibrée, plus cohérente, moins complexe et davantage inscrite dans la durée.

Enfin, ces projets doivent mobiliser des modèles économiques équilibrés entre les parties prenantes productrices et bénéficiaires. Ils devraient reposer sur une analyse au cas par cas de la rentabilité des infrastructures, dont le financement et l’exploitation croisent souvent acteurs privés et publics.

Les bonnes pratiques à adopter

Pour favoriser le succès des projets de REUT, il faut d’abord faire de la gestion responsable de l’eau une priorité dans chaque pays du monde. Cela implique d’inscrire dans la loi des instruments réglementaires de politique environnementale le permettant, sans alourdir et complexifier les cadres actuels.

Cela passe également par la promotion de mesures préalables. Notamment la sobriété, l’optimisation et le recyclage in situ des eaux lors de la conception puis l’exploitation de nouvelles d’infrastructures. Pour minimiser les impacts anthropiques de l’homme sur le cycle naturel de l’eau, il vaut mieux réutiliser un mètre cube d’eaux usées plutôt que de le puiser dans le milieu naturel.

Il convient d’intégrer dans l’analyse de rentabilité du projet, ses impacts et bénéfices sanitaires, sociaux et environnementaux sur l’ensemble de son cycle de vie, ainsi que le coût de renoncement global.

On pourrait également intégrer le recyclage de l’eau prélevée dans tous les schémas directeurs de l’aménagement et de gestion des eaux. La REUT peut ainsi être intégrée aux projets de territoire pour la gestion de l’eau (PTGE) et aux schémas d’aménagement et de gestion de l’eau (SAGE).

C’est à cette condition que l’on peut concevoir et planifier une réutilisation multiressource et multiusage (lorsqu’elle est possible et pertinente) des eaux usées. Cela permet de substituer la REUT à d’autres prélèvements sur le milieu ou à l’utilisation d’eau potable. Pour cela il faut prendre en compte de façon systématique les enjeux de restauration et de préservation des ressources et des écosystèmes

Cela nécessite également de repenser les appels d’offres et contrats de délégation de service public. Il faudrait tenir compte de la raison d’être et des fonctions diverses des stations de traitement des eaux usées, et élargir leur rôle de « stations d’épuration » à celui de véritables usines de valorisation, lorsque c’est pertinent.

Au-delà de la récupération de l’eau, on peut y prélever des nutriments, comme l’azote ou le phosphore, ou encore produire de la chaleur. Mais, pour que cela possible, il convient d’adapter en conséquence les instruments fiscaux, les modalités de tarification et plus largement les modèles économiques.

Renforcer le soutien financier à la recherche sur cette question est crucial. À diverses échelles, on peut par exemple citer le Défi Clé Water Occitanie (WOc), le projet REUTOSUD, le programme de financement Water4All ou encore le réseau européen de recherche Water4Reuse.

Cela passe aussi par la création et l’animation de structures de sensibilisation, d’échange de connaissances et de concertation. Celles-ci doivent impliquer les pouvoirs publics nationaux, régionaux et locaux aux côtés des autres parties prenantes. Ces dispositifs de recherche-action interdisciplinaire, appelés « Living Labs », sont ancrés dans les territoires et à l’interface science-politique-société. À l’image des Living Labs, mis en place dans le cadre du WOc déjà mentionné, ils doivent faciliter la conception d’outils, de services ou d’usages nouveaux autour du recyclage de l’eau.

Enfin, il convient de favoriser l’acculturation de toute la chaîne technique et administrative. Ceci passe par la formation initiale et continue des professionnels, des bureaux d’études, des élus et des fonctionnaires centraux et territoriaux. Ceci permettra une mise en œuvre plus aisée de ces nouvelles approches de gestion de l’eau, au service d’une économie circulaire de l’eau.


Les personnes suivantes ont collaboré à cet article, par ordre alphabétique :

Nassim Ait-Mouheb (Inrae ; Eau, Agriculture et Territoires), Claire Albasi (Université de Toulouse, Défi Clé Water Occitanie), Christophe Audouin (Suez), Gilles Belaud (Chaire EACC ; Eau, Agriculture et Territoires), Sami Bouarfa (Inrae ; Eau, Agriculture et Territoires), Frédéric Bouin (Université de Perpignan Via Domitia, UPVD), Pierre Compère (Explicite Conseil), Ehssan El Meknassi (Costea), Jérôme Harmand (Inrae ; Eau, Agriculture et Territoires), Marc Heran (Institut européen des membranes, Chaire SIMEV), Barbara Howes (SCP), Marie-Christine Huau (Veolia, Direction du Développement Eau), Vincent Kulesza (SCP ; Eau, Agriculture et Territoires), Rémi Lombard-Latune (Inrae ; EPNAC ; Groupe de travail national Eaux non conventionnelles), Alain Meyssonnier (Institut méditerranéen de l’eau), Bruno Molle (EIA/Inrae), Simon Olivier (Pôle de compétitivité Aqua-Valley), Carmela Orea (Eau, Agriculture et Territoires), Céline Papin (Eau, Agriculture et Territoires), Nicolas Roche (Aix-Marseille Université/University Mohammed VI Polytechnic, Eau, Agriculture et Territoires), Stéphane Ruy (Inrae, Institut Carnot), Pierre Savey (BRL ; Eau, Agriculture et Territoires) et Salomé Schneider (Chaire EACC).

The Conversation

Jérôme Harmand a reçu des financements de la Région Occitanie dans le cadre du financement du projet WOc WoD visant à étudier le traitement des eaux usées brutes pour les réutiliser. Il anime le réseau REUSE d’INRAE au niveau national et porte l’action COST CA23104 “Mainstreaming water reuse into the circular economy paradigm (Water4Reuse)”.

ref. Comment favoriser la réutilisation des eaux usées traitées en France ? – https://theconversation.com/comment-favoriser-la-reutilisation-des-eaux-usees-traitees-en-france-257141